Self-adhesive multi-layer item and method for the production thereof

Abstract

A self-adhesive multi-layer item comprising:1) a dorsal support DO having a top face SI1 and a bottom face SI2,2) at least one layer of silicone release coating RC applied to the top face SI1 of the dorsal support DO and which is prepared by irradiation of a curable silicone composition C not containing any solvent and comprising, as constituents:a) at least one functionalized organopolysiloxane Ab) an effective amount of at least one type I photoinitiator P of the family of acylphosphine oxide derivatives of formula (III)3) at least one adhesive PSA, preferably at least one pressure-sensitive adhesive PSA, applied on the layer of silicone release coating,4) a frontal support FR applied on the adhesive PSA of the component 3), and 5) optionally at least one layer of silicone release coating RC applied on the bottom face SI2 of the dorsal support DO and which is prepared by application and irradiation of said curable silicone composition C, and on this same layer, there is at least one adhesive PSA, preferably at least one pressure-sensitive adhesive PSA.

1 . A process for preparing a self-adhesive multi-layer item comprising a dorsal support DO having a top face SI 1  and a bottom face SI 2  and a first layer of silicone release coating RC, the process comprising a) to d):
 a) applying between 0.1 and 5 g per m 2  of the composition C on the top face SI 1  of the dorsal support DO to obtain the dorsal support DO coated with composition C, wherein composition C is a curable silicone composition not containing any solvent comprising 1 and 2: 
 1) at least one functionalized organopolysiloxane A comprising:
 i) at least one unit of formula (I):
   R a Z b SiO (4-a-b)/2   (I)
 
 wherein 
 R, which may be identical or different, each represent a linear or branched C 1  to C 18  alkyl group, a C 6  to C 12  aryl or aralkyl group, which is optionally substituted, optionally with halogen atoms, or an alkoxy radical —OR 4  with R 4  being a hydrogen atom or a hydrocarbon-based radical comprising from 1 to 10 carbon atoms,
 represents a monovalent radical of formula -y-(Y′) n  in which: 
  y represents a linear or branched C 1 -C 18  polyvalent alkylene radical optionally extended by C 1  to C 4  oxyalkylene or polyoxyalkylene divalent radicals, which is optionally substituted with a hydroxyl radical, 
  Y′ represents an alkenylcarbonyloxy monovalent radical, and 
  n is equal to 1, 2 or 3, and 
 a is an integer equal to 0, 1 or 2, b is an integer equal to 1 or 2 and the sum a+b=1, 2 or 3; and 
 
 
 ii) optionally units of formula (II) below:
   R a SiO (4-a)/2   (II)
 
 in which formula:
 the symbols R, which may be identical or different, each represent a linear or branched C 1  to C 18  alkyl group, a C 6  to C 12  aryl or aralkyl group, which is optionally substituted, optionally with halogen atoms, and 
 a is an integer equal to 0, 1, 2 or 3, and 
 
 
 
 2) an effective amount of at least one type I photoinitiator P of the family of acylphosphine oxide derivatives of formula (III) below: 
 
       
         
           
           
               
               
           
         
         
           in which formula:
 the symbol R 5  is a monovalent radical —O—R 8  with the symbol R 8  being a hydrocarbon-based radical comprising from 1 to 8 carbon atoms; 
 the symbol R 6  is a phenyl radical optionally substituted with:
 one or more halogen atom(s), 
 a hydrocarbon-based radical comprising from 1 to 8 carbon atoms, 
 a hydrocarbon-based alkoxy radical comprising from 1 to 8 carbon atoms, and/or 
 a hydrocarbon-based thio radical comprising from 1 to 8 carbon atoms; and 
 
 the symbol R 7  represents a hydrocarbon-based radical comprising from 1 to 12 carbon atoms, a benzyl radical or a phenyl radical optionally substituted with one or more halogen atom(s), a hydrocarbon-based radical comprising from 1 to 8 carbon atoms, a hydrocarbon-based alkoxy radical comprising from 1 to 8 carbon atoms and/or a cycloalkyl radical; 
 
         
         b) subjecting the dorsal support DO coated with the composition C to ultraviolet radiation in order to cure, by polymerization and/or crosslinking, the composition C to obtain a layer of silicone release coating RC, and 
         c) applying at least one adhesive PSA, optionally a pressure-sensitive adhesive PSA on the layer of silicone release coating RC, and then applying a frontal support FR on the adhesive PSA, 
         d) preparing an adhesive construction AD by applying, on a frontal support FR, at least one adhesive PSA, optionally one pressure-sensitive adhesive PSA, then joining the adhesive construction AD with the dorsal support DO coated with the composition C prepared in a) in such a way that the adhesive PSA is located between the dorsal support DO and the frontal support FR, and 
         e) optionally, applying the composition C on the bottom face SI 2  of the dorsal support DO and then subjecting it to ultraviolet radiation to cure, by polymerization and/or crosslinking, the composition C, to obtain a layer of silicone release coating RC on the bottom face SI 2  of the dorsal support DO, and subsequently applying at least one adhesive PSA, optionally at least one pressure-sensitive adhesive PSA, on the same layer of silicone release coating RC. 
       
     
     
         2 . The process as claimed in  claim 1 , wherein, in c), d), and/or e), an adhesive PSA, optionally a pressure-sensitive adhesive PSA, is applied in the form of an aqueous emulsion and is then dried. 
     
     
         3 . The process as claimed in  claim 1 , wherein, in b), the ultraviolet radiation has a wavelength of between 100 and 400 nanometers, limits included. 
     
     
         4 . An irradiation-curable silicone composition C which does not contain any solvent and which comprises as constituents:
 1) at least one functionalized organosiloxane or organopolysiloxane A comprising:
 i) at least one unit of formula (I) below:
   R a Z b SiO (4-a-b)/2   (I)
 
 in which formula:
 the symbols R, which may be identical or different, each represent a linear or branched C 1  to C 18  alkyl group, a C 6  to C 12  aryl or aralkyl group, which is optionally substituted, optionally with halogen atoms, or an alkoxy radical —OR 4  with R 4  being a hydrogen atom or a hydrocarbon-based radical comprising from 1 to 10 carbon atoms, 
 the symbols Z are monovalent radicals of formula -y-(Y′) n  in which: 
  y represents a linear or branched C 1 -C 18  polyvalent alkylene radical optionally extended by C 1  to C 4  oxyalkylene or polyoxyalkylene divalent radicals, which is optionally substituted with a hydroxyl radical, 
  Y′ represents an alkenylcarbonyloxy monovalent radical, and 
  n is equal to 1, 2 or 3, and 
 a is an integer equal to 0, 1 or 2, b is an integer equal to 1 or 2 and the sum a+b=1, 2 or 3; and 
 
 
 ii) optionally units of formula (II) below:
   R a SiO (4-a)/2   (II)
 
 in which formula:
 the symbols R, which may be identical or different, each represent a linear or branched C 1  to C 18  alkyl group, a C 6  to C 12  aryl or aralkyl group, which is optionally substituted, optionally with halogen atoms, and 
 a is an integer equal to 0, 1, 2 or 3, and 
 
 
   2) an effective amount of at least one type I photoinitiator P of the family of acylphosphine oxide derivatives of formula (III) below:   
       
         
           
           
               
               
           
         
         
           in which formula:
 the symbol R 5  is a monovalent radical —O—R 8  with the symbol R 8  being a hydrocarbon-based radical comprising from 1 to 8 carbon atoms; 
 the symbol R 6  is a phenyl radical optionally substituted with:
 one or more halogen atom(s), 
 a hydrocarbon-based radical comprising from 1 to 8 carbon atoms, 
 a hydrocarbon-based alkoxy radical comprising from 1 to 8 carbon atoms, and/or 
 a hydrocarbon-based thio radical comprising from 1 to 8 carbon atoms; and 
 
 the symbol R 7  represents a hydrocarbon-based radical comprising from 1 to 12 carbon atoms, a benzyl radical or a phenyl radical optionally substituted with one or more halogen atom(s), a hydrocarbon-based radical comprising from 1 to 8 carbon atoms, a hydrocarbon-based alkoxy radical comprising from 1 to 8 carbon atoms and/or a cycloalkyl radical. 
 
         
       
     
     
         5 . The irradiation-curable silicone composition C as claimed in  claim 4  wherein the photoinitiator P is ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate. 
     
     
         6 . A substrate at least partially coated with a release coating prepared by application of the curable silicone composition C as defined in  claim 4  and irradiation by ultraviolet radiation so as to bring about crosslinking thereof. 
     
     
         7 . The substrate at least partially coated with a release coating as defined in  claim 4 , wherein the substrate is selected from one or more of self-adhesive labels, of bands including envelopes, of graphic arts, of medical and hygiene care and of construction and insulation. 
     
     
         8 . A substrate at least partially coated with a release coating as defined in  claim 6 , in the field of one or more of self-adhesive labels, of bands including envelopes, of graphic arts, of medical and hygiene care and of construction and insulation.