WO1997005100A1 - Compose photoreticulant chromophore - Google Patents

Compose photoreticulant chromophore Download PDF

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Publication number
WO1997005100A1
WO1997005100A1 PCT/US1995/009600 US9509600W WO9705100A1 WO 1997005100 A1 WO1997005100 A1 WO 1997005100A1 US 9509600 W US9509600 W US 9509600W WO 9705100 A1 WO9705100 A1 WO 9705100A1
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WIPO (PCT)
Prior art keywords
compound
benzophenone
anthraquinone
chromone
thioxanthone
Prior art date
Application number
PCT/US1995/009600
Other languages
English (en)
Inventor
Steven M. Heilmann
Gaddam N. Babu
Larry R. Krepski
Howell K. Ii Smith
Daniel E. Mickus
Original Assignee
Minnesota Mining And Manufacturing Company
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Filing date
Publication date
Application filed by Minnesota Mining And Manufacturing Company filed Critical Minnesota Mining And Manufacturing Company
Priority to PCT/US1995/009600 priority Critical patent/WO1997005100A1/fr
Priority to EP96925546A priority patent/EP0837844B1/fr
Priority to JP50780797A priority patent/JP4344863B2/ja
Priority to CA002228010A priority patent/CA2228010A1/fr
Priority to PCT/US1996/012355 priority patent/WO1997005101A1/fr
Priority to DE69607620T priority patent/DE69607620T2/de
Publication of WO1997005100A1 publication Critical patent/WO1997005100A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
    • C07D311/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings ortho- or peri-condensed with carbocyclic rings or ring systems
    • C07D311/04—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring
    • C07D311/22—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring with oxygen or sulfur atoms directly attached in position 4
    • C07D311/26—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring with oxygen or sulfur atoms directly attached in position 4 with aromatic rings attached in position 2 or 3
    • C07D311/28—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring with oxygen or sulfur atoms directly attached in position 4 with aromatic rings attached in position 2 or 3 with aromatic rings attached in position 2 only
    • C07D311/30—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring with oxygen or sulfur atoms directly attached in position 4 with aromatic rings attached in position 2 or 3 with aromatic rings attached in position 2 only not hydrogenated in the hetero ring, e.g. flavones
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C233/00—Carboxylic acid amides
    • C07C233/01—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms
    • C07C233/34—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by amino groups
    • C07C233/42—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by amino groups with the substituted hydrocarbon radical bound to the nitrogen atom of the carboxamide group by a carbon atom of a six-membered aromatic ring
    • C07C233/44—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by amino groups with the substituted hydrocarbon radical bound to the nitrogen atom of the carboxamide group by a carbon atom of a six-membered aromatic ring having the carbon atom of the carboxamide group bound to a carbon atom of an unsaturated carbon skeleton
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C233/00—Carboxylic acid amides
    • C07C233/57—Carboxylic acid amides having carbon atoms of carboxamide groups bound to carbon atoms of rings other than six-membered aromatic rings
    • C07C233/60—Carboxylic acid amides having carbon atoms of carboxamide groups bound to carbon atoms of rings other than six-membered aromatic rings having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by singly-bound oxygen atoms
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • C08F20/52—Amides or imides
    • C08F20/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52—Amides or imides
    • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/58—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2603/00—Systems containing at least three condensed rings
    • C07C2603/02—Ortho- or ortho- and peri-condensed systems
    • C07C2603/04—Ortho- or ortho- and peri-condensed systems containing three rings
    • C07C2603/06—Ortho- or ortho- and peri-condensed systems containing three rings containing at least one ring with less than six ring members
    • C07C2603/10—Ortho- or ortho- and peri-condensed systems containing three rings containing at least one ring with less than six ring members containing five-membered rings
    • C07C2603/12—Ortho- or ortho- and peri-condensed systems containing three rings containing at least one ring with less than six ring members containing five-membered rings only one five-membered ring
    • C07C2603/18—Fluorenes; Hydrogenated fluorenes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2603/00—Systems containing at least three condensed rings
    • C07C2603/02—Ortho- or ortho- and peri-condensed systems
    • C07C2603/04—Ortho- or ortho- and peri-condensed systems containing three rings
    • C07C2603/22—Ortho- or ortho- and peri-condensed systems containing three rings containing only six-membered rings
    • C07C2603/24—Anthracenes; Hydrogenated anthracenes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2603/00—Systems containing at least three condensed rings
    • C07C2603/02—Ortho- or ortho- and peri-condensed systems
    • C07C2603/04—Ortho- or ortho- and peri-condensed systems containing three rings
    • C07C2603/30—Ortho- or ortho- and peri-condensed systems containing three rings containing seven-membered rings
    • C07C2603/32—Dibenzocycloheptenes; Hydrogenated dibenzocycloheptenes

Definitions

  • This invention relates to photoactive crosslinking compounds prepared by reacting an electrophilic 2-alkenyl azlactone compound and a nucleophilic aromatic ketone. These photoactive compounds can be used to crosslink, for example, acrylic polymers.
  • PSAs Background Information Pressure sensitive adhesives
  • U.S. Patent Nos. RE 24,906, 4,181,755, 4,364,972, and 4,243,500 Acrylic-based PSAs exhibit good adherence to high energy (i.e., polar) substrates.
  • Solvent-processed acrylic PSA compositions can be crosslinked by adding a polyfunctional crosslinking agent that reacts with a reactive group present in the polymer. See, e.g., Japanese Kokoku 58[1983]-046236 in which is described a solvent-processed crosslinked acrylic PSA wherein incorporated isocyanate groups are available for reaction with the crosslinking agent.
  • Hot melt coating a PSA composition eliminates the necessity of solvent processing.
  • the composition must be uncrosslinked during the coating process; however, to achieve a PSA with balanced properties (i.e., peel and shear adhesion), the composition eventually must be crosslinked.
  • high energy radiation e.g., E-beam or high intensity ultraviolet radiation.
  • a photoactive crosslinking species such as benzophenone is added to the composition.
  • a more efficient method of photocrosslinking involves inco ⁇ orating hydrogen abstracting moieties into the polymer backbone prior to coating.
  • Such polymers can be hot melt coated and subsequently cured by conventional irradiation techniques. This process is typified by U.S. Patent No. 4,737,599 where a PSA with good adhesion to skin is described.
  • the cohesive strength of an acrylic PSA can be increased without unduly affecting its compliance by utilizing a photoactive crosslinking agent in conjunction with a photoinitiator.
  • a photoactive crosslinking agent in conjunction with a photoinitiator.
  • Useful photoactive crosslinking agents include various aldehydes, quinones, and particularly certain chromophore- substituted halomethyl-.s-triazines (because they provide desirably shortened reaction times and somewhat greater tolerance to oxygen over the non- halomethyl-containing agents), although their use can result in evolution of HCl.
  • Copolymerizable photoinitiators such as 2-[4-(2-hydroxy-2,2-dimethyl-l- oxopropyl)phenoxy]ethyl 2-propenoate and their use in the polymerization of ethylenically unsaturated compounds is disclosed in U.S. Patent No. 4,922,004.
  • Japanese Kokai 2[1990]-248482 describes a photocurable PSA obtained by reacting (a) 30 to 50 parts by weight (pbw) of a copolymer of an acrylic acid alkyl ester, a copolymerizable ethylenically unsaturated monomer having a polar group, and a copolymerizable monomer with a photosensitizing group (such as 2- acryloyloxybenzophenone or 1 -acryloyloxy-2- [4-(4-chlorobenzoyl)benzoyl- oxy]ethane); (b) 40 to 60 pbw of an aryloxy acrylic monomer such as phenoxyethyl acrylate or nonylphenoxyethyl acrylate; and (c) a tackifying resin.
  • a photosensitizing group such as 2- acryloyloxybenzophenone or 1 -acryloyloxy-2- [4-(4-chlorobenz
  • composition is cured using a total dose of energy of 300 to 800 mJ/cm 2 from a high pressure mercury lamp.
  • high intensity ultraviolet radiation is likely to produce an adhesive that has a shear strength value less than 100 minutes.
  • DE 42 03 183 Cl Germany discloses a method for producing
  • PSA layers comprising the steps of thickening a monomer mixture that includes a photoinitiator with a separately made solvent-free saturated UN-reactive polyacrylate, coating the thickened mixture onto a substrate, and irradiating the coated substrate.
  • the separately made polymer comprises side chains that, when irradiated, participate in crosslinking reactions.
  • the sole example involves the addition of a commercially available polymer having a molecular weight of about 200,000 to a monomer mixture that is then polymerized.
  • PSAs prepared by actinically irradiating acrylic monomers can be enhanced by the addition of polyacrylic crosslinking agents. See, e.g., U.S. Patent No. 4,379,201.
  • Such PSAs involve networks and are sensitive to processing conditions.
  • An ultraviolet (UN) radiation-curable composition that includes a copolymer of ethylenically unsaturated monomers, ethylenically unsaturated monomers, and optionally one or more polyethylenically unsaturated compounds is described in U.S. Patent No. 5,180,756.
  • photocrosslink acrylic PSA compositions When attempting to photocrosslink acrylic PSA compositions, one of two broad categories of photoactive crosslinking agents is generally used: an ⁇ - cleaving agent or a hydrogen abstracting agent. Ofthe latter category, the most commonly used example is probably acryloylbenzophenone (ABP).
  • ABSP acryloylbenzophenone
  • Acrylic derivatives of anthraquinone, benzophenone, xanthone, thioxanthone, and 9-fluorenone have been described previously, as has an acrylamide derivative of anthraquinone.
  • none of these compounds has been described as being useful as a reactive crosslinker for PSA compositions. What has not been previously described is an easily prepared, effective hydrogen abstracting-type photocrosslinking agent that exhibits enhanced solubility in relatively non-polar monomers.
  • the present invention provides an easily synthesizable photoactive crosslinking compound that has the general formula
  • R 1 is H or a Ci to C 3 alkyl group, preferably H or a methyl group
  • R 2 and R 3 are independently H, an alkyl group having 1 to 14 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, an aryl group having 5 to 12 ring atoms, an arenyl group having 6 to 26 carbon and 0 to 3 S, N, and nonperoxidic O heteroatoms, or R 2 and R 3 taken together with the carbon to which they are attached form a carbocyclic ring containing 4 to 12 ring atoms; n is O or 1;
  • A is XCR 4 R 5 , p ⁇ CH CHR 1 )].,, or X— ⁇ (CHZCHR'Y)].
  • X is O, S, NH, or NR 4 ;
  • Y is O, C(O)O, OC(O)NH, OC(O)O, or NHC(O)O;
  • R 4 and R 5 are independently H, a Ci to C ⁇ alkyl group, or an aryl group; and m is 0 or 1;
  • Z is a moiety derived from an acetophenone, benzophenone, anthraquinone, 9- fluorenone, anthrone, xanthone, thioxanthone, acridone, dibenzosuberone, benzil, or chromone.
  • the present invention provides a method of making the above photoactive crosslinking compound comprising the steps of solubilizing and allowing to react a z-alkenyl azlactone compound and a nucleophilic aceto ⁇ phenone, benzophenone, anthraquinone, 9-fluorenone, anthrone, xanthone, thioxanthone, acridone, dibenzosuberone, benzil, or chromone.
  • This reaction can be facilitated by the addition of a catalyst comprising a nitrogen-containing base, preferably a bicyclic amidine or guanidine, or a trivIER phosphorous compound.
  • group or “compound” or “moiety” or “monomer” or “polymer” means, unless otherwise noted, a chemical species that can be substituted by conventional substituents that do not interfere with the desired product, e.g., alkyl, alkoxy, aryl, dialkylamino, halo, nitro, and cyano groups;
  • alkyl means the monovalent residue remaining after removal of one hydrogen atom from a saturated linear or branched chain hydrocarbon having 1 to 14 carbon atoms;
  • aryl means the monovalent residue remaining after removal of one hydrogen atom from an aromatic or heteroaromatic compound that can consist of one ring or two fused or catenated rings having 5 to 12 ring atoms which can include up to 3 heteroatoms selected from S, N, and nonperoxidic O, and in which the carbon atoms can be substituted by up to three halogen atoms, Ci to C 4 alkyl groups, Ci to C 4 alkoxy groups, N,N-di(C ⁇ to C alkyl)amino groups, nitro groups, cyano groups, and C ⁇ -C 4 alkyl carboxylic ester groups; and
  • n, R 1 , R 2 , and R 3 are defined as before.
  • the photoactive crosslinking compound ofthe present invention can be used to crosslink, for example, acrylic adhesive compositions in much the same way as ABP.
  • the synthesis ofthe photoactive crosslinking compound ofthe present invention involves a simple addition reaction of an electrophilic azlactone and a nucleophilic aromatic ketone with no side products being created.
  • addition products are acrylamidoacetyl- (or propionyl-) functional and, accordingly, are very reactive in free radical-initiated mono- and copolymerization reactions. Also, the addition products are more hydrolytically stable than their acrylate counterparts.
  • a significant advantage of using the 2-alkenyl azlactone instead of acryloyl chloride as an acylating agent is that the azlactone nucleophile reaction involves ring-opening addition; no smaller by-product molecule (such as hydrogen chloride) is displaced or generated in the reaction.
  • the acrylamide functionality can offer certain advantages as a polymerizable group over the acrylate.
  • the amide group is known to be more difficult to hydrolyze than the ester group; therefore, amide-functional polymers are expected to be more environmentally stable.
  • acrylamides enjoy rates of free radical polymerization substantially faster than corresponding acrylates or methacrylates.
  • N,N-Dimethylacrylamide exhibits a rate of bulk polymerization (k p 2 /k t ) at 50°C 1142 times faster than methyl acrylate and 457 times faster than methyl methacrylate.
  • the acrylamide derivatized compounds ofthe present invention also provide an advantage over the previously described acrylamide derivative of anthraquinone in that the compounds ofthe present invention are more soluble in non-polar monomers because ofthe longer chain length between the unsaturated group and the carbocycle moiety.
  • the carbon atoms in the chain aid in solubilizing the compounds ofthe present invention when used in conjunction with non-polar monomers.
  • the nucleophilic group (from A) is separated from the ring system of Z by at least one, preferably two, methylene groups.
  • the various compounds from which Z can be derived are all aromatic ketones. Such ketones are known to be "hydrogen abstracting agents". When activated by abso ⁇ tion of ultraviolet light, these Z groups can act to crosslink various polymer systems.
  • Z is a moiety derived from an acetophenone, benzophenone, anthraquinone, 9-fluorene, anthrone, xanthone, thioxanthone, acridone, dibenzosuberone, benzil, or chromone.
  • nucleophilic aromatic ketones can be substituted with any functional group that is not a nucleophile (which would interfere in the reaction ofthe nucleophilic group ofthe aromatic ketone with the electrophilic azlactone).
  • Potentially useful functional groups include alkyl, alkoxy, aryl, dialkylamino, halo, nitro, and cyano groups.
  • Preferred Z groups include those derived from an acetophenone, benzophenone, anthraquinone, thioxanthone, chromone, and benzil. Particularly preferred are benzophenone and anthraquinone.
  • Preferred photoactive crosslinking compounds include those where X (in A) is oxygen or NH, and where n is 0. Examples of preferred crosslinking compounds have the general formula
  • R 1 is H or a methyl group (preferably H)
  • D is — (OCH 2 CH 2 O) — or — (NHCH 2 CH 2 O) —
  • Z is a moiety derived from those compounds listed previously, preferably from an acetophenone, benzophenone, anthraquinone, thioxanthone, chromone, or benzil.
  • Particularly preferred among those compounds ofthe above formula are those where D is — (OCH 2 CH 2 O) — -
  • the photoactive crosslinking compound ofthe present invention can be prepared by the ring-opening of an electrophilic 2-alkenyl azlactone compound and simultaneous reaction with a nucleophile-substituted aromatic ketone.
  • Suitable nucleophiles include hydroxyl, primary amine, secondary amine, and thiol groups.
  • Alkenyl azlactones can be prepared by methods well known in the art. See, e.g., Iwakura et al., Tetrahedron, 23, 3363 (1967); Hubner et al., Makromol. Chem., 11, 109 (1970); Taylor et al., J. Poly. Sci., Poly. Let. Ed, 7, 597 (1969); and U.S. Patent Nos. 4,304,705 and 4,777,276.
  • acylating agent preferably containing a polymerization inhibitor such as hydroquinone
  • an acid absorber e.g., aqueous NaOH
  • aqueous solution of an equimolar amount of an alkali metal salt ofthe amino acid, followed by neutralization with an aqueous acid (e.g., 6 N HCl), and isolation ofthe unsaturated peptide carboxylic acid product.
  • This product is then dehydrated by introduction of a dehydrating agent (such as, for example, acetic anhydride, ethyl chloroformate, or dicyclohexylcarbodiimide) to give a 2-alkenyl azlactone.
  • a dehydrating agent such as, for example, acetic anhydride, ethyl chloroformate, or dicyclohexylcarbodiimide
  • 5-membered ring species are preferred.
  • suitable 5-membered ring azlactones include 2- ethenyl- 1 ,3-oxazolin-5-one; 2-ethenyl-4-methyl- 1 ,3-oxazolin-5-one; 2- isopropenyl- l,3-oxazolin-5-one; 2-isopropenyl-4-methyl-l,3-oxazolin-5-one; 2- ethenyl-4,4-dimethyl-l,3-oxazolin-5-one; 2-isopropenyl-4,4-dimethyl-l,3- oxazolin-5-one; 2-ethenyl-4-methyl-4-ethyl- 1 ,3-oxazolin-5-one; 2-isopropenyl-4- methyl-4-ethyl-l,3-oxazoltone
  • Preferred azlactones are 2-ethenyl-4,4-dimethyl-l,3- oxazolin-5-one and 2-isopropenyl-4,4-dimethyl-l,3-oxazolin-5-one.
  • Nucleophile-substituted aromatic ketones that can be used in the present invention include, but are not limited to, the following compounds:
  • chromone flavone (a type of chromone)
  • the ring-opening reaction ofthe electrophilic azlactone compound and the nucleophile-substituted aromatic ketone can be catalyzed by nitrogen-containing bases, such as bicyclic amidines and guanidines, or trivending phosphorus compounds.
  • bases such as bicyclic amidines and guanidines, or trivending phosphorus compounds.
  • Bases that have been found to be particularly useful catalysts are selected from the group consisting of
  • R 6 and R 7 independently represent an alkylene group or an alkyl- or aryl- substituted alkylene group of 2 to 12 carbon atoms
  • R 8 is an alkyl or aryl group
  • m is 0 when the base is an amidine or 1 when the base is a guanidine
  • amidines examples include l,5-diazabicyclo[4.3.0]non-5-ene
  • DBU l,8-diazabicyclo[5.4.0]undec-7-ene
  • TBD l,5,7-triazabicyclo[4.4.0]dec-5-ene
  • DBN and DBU are available from Aldrich Chemical Co. (Milwaukee, Wis.) while TBD is available from Fluka Chemical Co ⁇ . (Ronkonkoma, NY). These and other amidines can also be prepared by methods well known in the art.
  • Examples of useful trivarri phosphorus compounds include trimethylphosphine, triethylphosphine, triethylphosphite, tributylphosphine, trioctylphosphine, tris(dimethylamino)phospine, dimethylphenylphosphine, diphenylmethylphosphine diphenylphosphine, dipropylphosphine, l,2-bis(di-n- propylphosphino)ethane, l,3-bis(diphenylphosphino)propane, diethylmethoxyphosphine, and triphenylphosphine.
  • the amount of catalyst utilized in the instant process can vary from about 0.1 mole percent (based on the amount of azlactone present) to about 50 mole percent or more. However, 0.5 to 5 mole percent is sufficient to provide a reasonable reaction rate in most instances.
  • the reactants are preferably allowed to react at room temperature (about 25 °C) to form the photactive crosslinking compound ofthe present invention.
  • room temperature about 25 °C
  • reaction temperatures from about 0°C to about 100°C or so can be utilized to carry out the process ofthe instant invention.
  • nonreactive solvents or diluents can be utilized to facilitate or mediate the reaction.
  • nonreactive is meant that the solvents do not contain functional groups that can react with either the azlactone, the aromatic ketone, or the catalyst (when present) under the conditions utilized.
  • Suitable nonreactive organic solvents include, for example, ethyl acetate, toluene, xylene, acetone, methyl ethyl ketone, acetonitrile, tetrahydrofuran, hexane, heptane, dimethylformamide, dimethylacetamide, and combinations thereof.
  • an effective amount e.g., 0.00005 to 0.5 weight percent based on the combined weight of azlactone and aromatic ketone
  • an antioxidant or free radical inhibitor such as a hindered phenol
  • the photoactive crosslinking compounds ofthe present invention can be used in the preparation of viscoelastomeric materials, preferably PSAs. This can be accomplished by mixing from about 0.0001 to about 5 parts by weight (pbw) of a photoactive crosslinking compound into 95 to 99.9999 pbw ethylenically unsaturated monomer(s) (such as, for example, acrylic acid and isooctyl acrylate). This can be done either before or after the monomer(s) have been partially polymerized to form a monomer-polymer syrup.
  • pbw ethylenically unsaturated monomer(s)
  • monomer(s) such as, for example, acrylic acid and isooctyl acrylate
  • This syrup is preferably of a coatable viscosity and is polymerizable to a viscoelastomeric material that can be crosslinked directly or hot-melt coated (for example, when no polyethylenically unsaturated monomer is present) and then crosslinked.
  • the viscoelastomeric material is preferably a PSA having high shear at both ambient and elevated temperatures.
  • the syrup comprises a solute polymer in a solvent monomer mixture.
  • the polymer preferably has a very high molecular weight (e.g., at least about 100,000), preferably at least 500,000, more preferably at least 750,000, even more preferably at least 1,000,000, most preferably at least 1,500,000.
  • One or both ofthe polymer and monomer contains at least one radiation-sensitive hydrogen abstracting group (from the photoactive crosslinking compound that, upon exposure to UN radiation, is activated to enable curing.
  • the cured product is a crosslinked viscoelastomeric material.
  • the polymer ofthe syrup contains side chains that comprise radiation- sensitive hydrogen abstracting groups activatable by UN radiation, resulting in a crosslinked viscoelastomeric product.
  • some polymer that includes side chains comprising the aforementioned radiation-sensitive hydrogen abstracting groups or some photoactive crosslinking compound must be added to the syrup prior to formation ofthe viscoelastomeric material therefrom, i.e., polymerization ofthe monomer(s) ofthe monomer mixture.
  • the solute polymer is prepared in situ, i.e., directly from the solvent monomer mixture. This eliminates the need for solubilizing a separately made polymer in a monomer mixture and allows very high molecular weight polymers to be formed and solubilized.
  • Crosslinked viscoelastomeric materials produced from such a syrup can be used as PSAs, vibration damping materials, transfer adhesives, structural adhesives, protective coatings, and the like.
  • a syrup can have a coatable viscosity and can therefore be applied to a substrate prior to curing, thus allowing for the simple production of articles comprising one or more layers ofthe aforementioned viscoelastomeric material.
  • a saturated energy-activated initiator of polymerization is used in forming the polymer component ofthe syrup from the solvent monomer component.
  • energy-activated sources can be either heat- or UN radiation- activated. Examples of heat-activated sources include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, azobis(isobutyronitrile), and methyl ethyl ketoperoxide.
  • Useful UN radiation-activated initiators include the benzoin ethers such as benzoin methyl ether and benzoin ispropyl ether; substituted acetophenones such as 2,2-diethoxyacetophenone, commercially available as IrgacureTM 651 photoinitiator (Ciba-Geigy Co ⁇ .; Ardsley, ⁇ Y), 2,2-dimethoxy-2- phenyl-1-phenylethanone, commercially available as EsacureTM KB-1 photo ⁇ initiator (Sartomer Co.; West Chester, PA), and dimethoxyhydroxyacetophenone; substituted ⁇ -ketols such as 2-methyl-2-hydroxy propiophenone; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; and photoactive oximes such as l-phenyl-l,2-propanedione-2-(O-ethoxycarbonyl)oxime.
  • benzoin ethers such
  • a saturated energy-activated source of free radicals can be present in an amount from 0.0001 to about 3 pbw, preferably from about 0.001 to about 1.0 pbw, more preferably from about 0.005 to about 0.5 pbw, per 100 pbw ofthe solvent monomer mixture.
  • the saturated energy-activated initiator of polymerization initiates the polymerization ofthe free radically-polymerizable ethylenically unsaturated monomers.
  • a photoactive crosslinking compound is also present, it also can be inco ⁇ orated into the backbone chain ofthe polymer, resulting in radiation- sensitive hydrogen abstracting groups pendent from the backbone chain.
  • the syrup can be exposed to heat only or to heat and UN radiation so as to initiate polymerization ofthe monomer mixture.
  • One or more free radically-polymerizable polyethylenically unsaturated monomers can be included in the monomer mixture or, preferably, added to the syrup. Use of such monomer(s) allows for a reduction in the amount of photoactive crosslinking compound necessary to produce a viscoelastomeric material.
  • viscoelastomeric films can be prepared directly from the solvent monomer mixture (by quickly polymerizing a coated layer ofthe monomer to a polymer/monomer mixture), increasing the viscosity ofthe monomer mixture to a level more suitable for coating is preferred. This is readily accomplished by exposing the monomer(s) to a source of energy until about 0.1 to 35% (by wt.), preferably about 1 to 10% (by wt.), more preferably about 3 to 7% (by wt.), ofthe monomers have polymerized. If the source of energy is heat, a heat-activated initiator of free radicals can be included in the composition.
  • a radiation-activated source of free radicals can be used but is not absolutely required where a monomer ofthe monomer mixture contains a radiation sensitive group that produces free radicals on exposure to suitable radiation. Use of a radiation-activated source of free radicals is preferred in such situations, however.
  • the syrup is preferably prepared in situ by mixing one or more free radically-polymerizable ethylenically unsaturated monomers and 0 to 3 pbw of one or more ofthe photoactive crosslinking compounds and then polymerizing the monomer(s) to form a solute polymer.
  • the monomers can be added in any order. Where no radiation-sensitive hydrogen abstracting groups are present in either the solute polymer or the solvent monomer mixture, some of these groups must be introduced into the syrup prior to formation ofthe viscoelastomeric material.
  • a syrup of a coatable viscosity can be applied to a substrate, preferably a flexible carrier web, using any conventional coating means such as roller coating, dip coating, knife coating, and extrusion coating.
  • the substrate can further comprise a release coating between the substrate and the syrup or on the side of the substrate opposite the side on which the syrup is coated.
  • a crosslinked viscoelastomeric material can be prepared therefrom in a variety of ways. In each method, however, the remaining monomer(s) in the syrup are polymerized by exposure to radiation that activates the hydrogen abstracting groups and facilitates crosslinking.
  • One way to make the viscoelastomeric material from the remaining monomer(s) is to irradiate the syrup with both high and low intensity UN radiation.
  • Low intensity radiation is defined as 10 mW/cm 2 or less (as measured in accordance with procedures approved by the United States National Institute of Standards and Technology as, for example, with a UVTMAPTM UM 365 L-S radiometer manufactured by Electronic Instrumentation & Technology, Inc., in Sterling, VA), preferably in the wavelength region of 200 to 600 nm, preferably 280 to 400 nm.
  • High intensity radiation is defined as anything greater than 10 mW/cm 2 , preferably between 15 and 450 mW/cm 2 . When such radiation is used, the viscoelastomeric material can be formed directly from the syrup.
  • Polymerization is preferably performed in an inert (i.e., oxygen free) atmosphere, such as a nitrogen atmosphere.
  • an inert atmosphere i.e., oxygen free
  • Tolerance to oxygen can be increased by including in the syrup an oxidizable tin compound, as is taught in U.S. Patent No. 4,303,485.
  • a monomer-polymer syrup can be cured in air by covering a layer ofthe photoactive coating with a plastic film that is substantially transparent to UV radiation but impervious to oxygen and irradiating the composition through that film using UV lamps that emit light in the wavelength range corresponding to the abso ⁇ tion maximum ofthe hydrogen abstracting groups and saturated photoinitiator.
  • UV lamps that emit light in the wavelength range corresponding to the abso ⁇ tion maximum ofthe hydrogen abstracting groups and saturated photoinitiator.
  • Several different commercially available lamps including medium pressure mercury lamps and low-intensity fluorescent lamps, can be used.
  • the radiation intensity of these lamps is preferably adjusted so that the radiation intensity at the surface ofthe coating is less than 20 mW/cm 2 , preferably 0.5 to 6 mW/cm 2 , each having emission maxima between 200 and 600 nm, preferably between 280 and 400 nm.
  • the syrup preferably is exposed to a heat source either before or simultaneously with exposure to radiation of a wavelength that activates the hydrogen abstracting groups present in the monomer and/or the polymer ofthe syrup.
  • the energy-activated initiator in the syrup is a saturated UV radiation-activated initiator
  • the syrup preferably is exposed first to a wavelength of radiation that activates the saturated initiator until the monomers polymerize to a coatable viscosity so that the syrup can be coated on a substrate.
  • This coated composition is exposed to radiation of a wavelength to which at least the hydrogen abstracting group ofthe photoactive crosslinking compound is sensitive at an intensity of less than 10 mW/cm 2 (for a total dose of 30 to 800 mJ/cm 2 ) so as to further polymerize the monomers as well as crosslink the polymer chains.
  • ABSP acryloxybenzophenone
  • Examples 2-6) or AcBP (Examples 12-16).
  • ABP or AcBP was not added until after the contents of the jar had been partially polymerized so as to provide a syrup.
  • Each jar was purged with nitrogen and the contents exposed to low intensity UV radiation so as to partially polymerize the monomers and form coatable mixtures.
  • To each mixture was added an additional 0.12 pph 2,2-dimethoxy-2-phenyl-l-phenylethanone, 0.05 pph HDDA, and, to the jars to which no ABP or AcBP had previously been added, varying amounts of ABP (Examples 7-11) or AcBP (Examples 17-21).
  • each mixture was coated on polyethylene-coated silicone treated paper release liner at a thickness of 0.13 mm while the oxygen level ofthe curing chamber was maintained at about 200 ppm, each coated mixture was exposed to low intensity radiation for about 104 seconds at an average intensity of 2.0 mW/cm 2 . Both shear strength and peel strength measurements were then taken. A 200 mJ/cm 2 high intensity exposure at an average intensity of 18 mW/cm 2 was thereafter applied and the peel strength values were again measured.
  • test procedures were the same as described above with the exception that the stainless steel peel test were performed 20 minutes after the adhesive films were applied to the substrates.
  • Syrups including AcAc were coated, polymerized, and tested in the same manner as described in Examples 2-21. The results are given below in Table II. (All samples were exposed to high intensity radiation).

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

L'invention concerne un composé photosensible qui est le produit de réaction d'un composé alcényl-azlactone et d'une cétone aromatique nucléophile. On peut utiliser ce composé, par exemple, pour réticuler des polymères acryliques via un mécanisme d'extraction de l'hydrogène.
PCT/US1995/009600 1995-07-28 1995-07-28 Compose photoreticulant chromophore WO1997005100A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
PCT/US1995/009600 WO1997005100A1 (fr) 1995-07-28 1995-07-28 Compose photoreticulant chromophore
EP96925546A EP0837844B1 (fr) 1995-07-28 1996-07-26 Derives d'acrylamide a composes chromophores, servant d'agents de photoreticulation
JP50780797A JP4344863B2 (ja) 1995-07-28 1996-07-26 発色団光架橋化合物としてのアクリルアミド誘導体
CA002228010A CA2228010A1 (fr) 1995-07-28 1996-07-26 Derives d'acrylamide a composes chromophores, servant d'agents de photoreticulation
PCT/US1996/012355 WO1997005101A1 (fr) 1995-07-28 1996-07-26 Derives d'acrylamide a composes chromophores, servant d'agents de photoreticulation
DE69607620T DE69607620T2 (de) 1995-07-28 1996-07-26 Acrylamid-derivate als chromophore lichtvernetzbare verbindungen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1995/009600 WO1997005100A1 (fr) 1995-07-28 1995-07-28 Compose photoreticulant chromophore

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WO1997005100A1 true WO1997005100A1 (fr) 1997-02-13

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996005249A2 (fr) 1994-07-29 1996-02-22 Minnesota Mining And Manufacturing Company Sirop acrylique donnant apres durcissage une matiere viscoelastomere reticulee
US6139770A (en) * 1997-05-16 2000-10-31 Chevron Chemical Company Llc Photoinitiators and oxygen scavenging compositions
WO2010065355A1 (fr) * 2008-12-02 2010-06-10 3M Innovative Properties Company Composés de réticulation photoactifs à fonction aziridine
US8067504B2 (en) 2009-08-25 2011-11-29 3M Innovative Properties Company Acrylic pressure-sensitive adhesives with acylaziridine crosslinking agents
US8148471B2 (en) 2009-11-23 2012-04-03 3M Innovative Properties Company Acrylic pressure-sensitive adhesives with aziridinyl-epoxy crosslinking system
US8263711B2 (en) 2009-12-23 2012-09-11 3M Innovative Properties Company (Meth)acryloyl-aziridine crosslinking agents and adhesive polymers
US8420214B2 (en) 2008-06-09 2013-04-16 3M Innovative Properties Company Acrylic pressure-sensitive adhesives with aziridine crosslinking agents
US8524836B2 (en) 2010-01-20 2013-09-03 3M Innovative Properties Company Crosslinkable acrylate adhesive polymer composition
US9758547B2 (en) 2010-03-03 2017-09-12 3M Innovative Properties Company Ligand functionalized polymers

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995010552A1 (fr) * 1993-10-13 1995-04-20 Lowell Engineering Corporation Photo-initiateurs a base d'acetylarylcetones disubstituees fonctionnelles acrylamide

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995010552A1 (fr) * 1993-10-13 1995-04-20 Lowell Engineering Corporation Photo-initiateurs a base d'acetylarylcetones disubstituees fonctionnelles acrylamide

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996005249A2 (fr) 1994-07-29 1996-02-22 Minnesota Mining And Manufacturing Company Sirop acrylique donnant apres durcissage une matiere viscoelastomere reticulee
US6139770A (en) * 1997-05-16 2000-10-31 Chevron Chemical Company Llc Photoinitiators and oxygen scavenging compositions
US6852894B2 (en) 1997-05-16 2005-02-08 Chevron Phillips Chemical Company Lp Tribenzoyl compounds
US8420214B2 (en) 2008-06-09 2013-04-16 3M Innovative Properties Company Acrylic pressure-sensitive adhesives with aziridine crosslinking agents
CN102292317B (zh) * 2008-12-02 2015-01-28 3M创新有限公司 氮丙啶官能化光活性交联化合物
CN102292317A (zh) * 2008-12-02 2011-12-21 3M创新有限公司 氮丙啶官能化光活性交联化合物
US7838110B2 (en) 2008-12-02 2010-11-23 3M Innovative Properties Company Aziridine-functional photoactive crosslinking compounds
WO2010065355A1 (fr) * 2008-12-02 2010-06-10 3M Innovative Properties Company Composés de réticulation photoactifs à fonction aziridine
US8067504B2 (en) 2009-08-25 2011-11-29 3M Innovative Properties Company Acrylic pressure-sensitive adhesives with acylaziridine crosslinking agents
US8349962B2 (en) 2009-08-25 2013-01-08 3M Innovative Properties Company Acrylic pressure-sensitive adhesives with acylaziridine crosslinking agents
US8148471B2 (en) 2009-11-23 2012-04-03 3M Innovative Properties Company Acrylic pressure-sensitive adhesives with aziridinyl-epoxy crosslinking system
US8263711B2 (en) 2009-12-23 2012-09-11 3M Innovative Properties Company (Meth)acryloyl-aziridine crosslinking agents and adhesive polymers
US8524836B2 (en) 2010-01-20 2013-09-03 3M Innovative Properties Company Crosslinkable acrylate adhesive polymer composition
US9758547B2 (en) 2010-03-03 2017-09-12 3M Innovative Properties Company Ligand functionalized polymers
US10005814B2 (en) 2010-03-03 2018-06-26 3M Innovative Properties Company Ligand functionalized polymers
US10526366B2 (en) 2010-03-03 2020-01-07 3M Innovative Properties Company Ligand functionalized polymers

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