Pressure Sensitive Adhesive Tape for the Adhesion of Printing Plates and Method for the Production Thereof

Abstract

A pressure-sensitive adhesive tape made of a flat support material provided with a pressure sensitive adhesive comprising a polymer formed from a monomer mixture of acrylic acid ester and/or methyl acrylic acid ester or free acids thereof of the formula CH 2 =CH(R 1 )(COOR 2 ), acrylic acid ester and/or methyl acrylic acid ester having the formula CH 2 =CH(R 3 )(COOR 4 ) and acrylic aid ester and/or methyl acrylic acid ester having the formula CH 2 =CH(R 3 )(COOR 5 ).

1 . A pressure-sensitive adhesive tape having a flat carrier material which is coated on both sides with a pressure-sensitive adhesive, wherein at least one side of the carrier material is coated with a pressure-sensitive adhesive comprising polymers formed from a monomer mixture of at least the following components:
 i.a) 49.5%-89.5% by weight (based on the monomer mixture) of acrylic esters and/or methacrylic esters and/or the corresponding free acids with the following formula:
   CH 2 =CH(R 1 )(COOR 2 ), 
   where R 1 =H or CH 3  and R 2  is an alkyl radical having 1 to 10 carbon atoms or H and the homopolymer possesses a static glass transition temperature of <−30° C.;   i.b) 10% to 40% by weight (based on the monomer mixture) of acrylic esters and/or methacrylic esters with the following formula:
   CH 2 =CH(R 3 )(COOR 4 ), 
   where R 3 =H or CH 3  and R 4  is a cyclic alkyl radical having at least 8 carbon atoms or a linear alkyl radical having at least 12 carbon atoms and the homopolymer possesses a static glass transition temperature of at least 30° C.;   i.c) 0.5%-10% by weight (based on the monomer mixture) of acrylic esters and/or methacrylic esters with the following formula:
   CH 2 =CH(R 3 )(COOR 5 ), 
   where R 3 =H or CH 3  and R 5 =H or an aliphatic radical containing a functional group X, X comprising COOH, OH, —NH, NH 2 , SH, SO 3 H, and the homopolymer possesses a static glass transition temperature of at least 30° C.   
   
   
       2 . The pressure-sensitive adhesive tape of  claim 1 , wherein the polymers of the pressure-sensitive adhesive have a molar mass M n  of between about 10 000 and about 600 000 g/mol. 
   
   
       3 . The pressure-sensitive adhesive tape of  claim 1 , wherein the polymers of the pressure-sensitive adhesive are crosslinked. 
   
   
       4 . The pressure-sensitive adhesive tape of  claim 1 , wherein said polymers are present in a branched state as graft polymers. 
   
   
       5 . The pressure-sensitive adhesive tape of  claim 1 , wherein said pressure-sensitive adhesive comprises tackifier resins. 
   
   
       6 . The pressure-sensitive adhesive tape of  claim 5 , wherein the weight fraction of the tackifier resins as a proportion of the polymer is up to 40% by weight. 
   
   
       7 . The pressure-sensitive adhesive tape of  claim 1 , wherein the pressure-sensitive adhesive comprises additives selected from the group consisting of plasticizers, fillers, nucleators, expandants, compounding agents, aging inhibitors, and light stabilizers. 
   
   
       8 . The pressure-sensitive adhesive tape of  claim 1 , wherein the carrier material is a film, of polyester, PET, PE, PP, BOPP or PVC. 
   
   
       9 . The pressure-sensitive adhesive tape  claim 1 , wherein the carrier material is a polymer foam of PU, PVC or polyolefin. 
   
   
       10 . The pressure-sensitive adhesive tape  claim 1 , wherein the carrier material is a combination of a film and at least one foam carrier, the film being connected by adhesive bonding to the at least one foam carrier. 
   
   
       11 . The pressure-sensitive adhesive tape of  claim 8 , wherein the film is a film made of PET and has a thickness of 5 to 500 μm. 
   
   
       12 . The pressure-sensitive adhesive tape of  claim 1 , wherein the carrier material is pretreated by flame, corona and/or plasma, and/or chemically, and/or by provision with primer. 
   
   
       13 . The pressure-sensitive adhesive tape of  claim 1 , having a liner on one or both sides. 
   
   
       14 . The pressure-sensitive adhesive tape of  claim 1 , wherein two sides of the adhesive tape are coated with pressure-sensitive adhesive, and the two sides of the adhesive tape have pressure-sensitive adhesives differing in bond strength. 
   
   
       15 . A free-radical polymerization method of producing the pressure-sensitive adhesive tape of  claim 1 , wherein a reaction solution of a monomer mixture comprising at least the following components:
 i.a) 49.5%-89.5% by weight (based on the monomer mixture) of acrylic esters and/or methacrylic esters and/or the corresponding free acids with the following formula:
   CH 2 =CH(R 1 )(COOR 2 ), 
   where R 1 =H or CH 3  and R 2  is an alkyl radical having 1 to 10 carbon atoms or H and the homopolymer possesses a static glass transition temperature of <−30° C.;   i.b) 10% to 40% by weight (based on the monomer mixture) of acrylic esters and/or methacrylic esters with the following formula:
   CH 2 =CH(R 3 )(COOR 4 ), 
   where R 3 =H or CH 3  and R 4  is a cyclic alkyl radical having at least 8 carbon atoms or a linear alkyl radical having at least 12 carbon atoms and the homopolymer possesses a static glass transition temperature of at least 30° C.;   i.c) 0.5%-10% by weight (based on the monomer mixture) of acrylic esters and/or methacrylic esters with the following formula:
   CH 2 =CH(R 3 )(COOR 5 ), 
   where R 3 =H or CH 3  and R 5 =H or an aliphatic radical containing a functional group X, X comprising COOH, OH, —NH, NH 2 , SH, SO 3 H, and the homopolymer possesses a static glass transition temperature of at least 30° C.,   with the addition of an initiator having a grafting activity of ε<5 and of an initiator having a grafting activity of ε>5, is prepared and polymerized, and the resulting polymers are crosslinked.   
   
   
       16 . The method of  claim 15 , wherein first the initiator having a grafting activity of ε<5 is added for a linear polymerization and then the initiator having a grafting activity of ε>5 is added for a graft polymerization of the reaction solution. 
   
   
       17 . The method of  claim 16 , wherein after the initiator having a grafting activity of ε<5 is added and before the initiator having a grafting activity of ε>5 is added, initiation is repeated at least once with an initiator having a grafting activity of ε<5. 
   
   
       18 . The method of any one of  claims 15  to  17 , characterized in that the reaction is controlled by diluting the reaction solution in accordance with the viscosity of the polymer. 
   
   
       19 . The method of any one of  claims 15  to  17 , wherein the polymerization is carried out at a temperature of 50-90° C. 
   
   
       20 . The method of any one of  claims 15  to  17 , wherein the initiator having a grafting activity of ε>5 is used in an amount of up to 2% by weight, based on the monomer mixture. 
   
   
       21 . The method of any one of  claims 15  to  17 , wherein the initiator having a grafting activity of ε>5 has a grafting activity ofε>10. 
   
   
       22 . The method of any one of  claims 15  to  17 , wherein the initiator having a grafting activity of ε<5 is 2,2-azobis(2-methylbutyronitrile). 
   
   
       23 . The method of any one of  claims 15  to  17 , wherein the polymerization is carried out to a conversion of at least 90. 
   
   
       24 . The method of any one of  claims 15  to  17 , wherein the method is carried out as a controlled polymerization with the addition of regulator substances. 
   
   
       25 . The method of  claim 24 , wherein said regulator is selected from the group consisting of 2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (PROXYL), 3-carbamoyl-PROXYL, 2,2-dimethyl-4,5-cyclohexyl-PROXYL, 3-oxo-PROXYL, 3-hydroxylimine-PROXYL, 3-aminomethyl-PROXYL, 3-methoxy-PROXYL, 3-t-butyl-PROXYL, 3,4-di-t-butyl-PROXYL; 2,2,6,6-tetramethyl-1-piperidinyloxyl-(TEMPO), 4-benzoyloxy-TEMPO, 4-methoxy-TEMPO, 4-chloro-TEMPO, 4-hydroxy-TEMPO, 4-oxo-TEMPO, 4-amino-TEMPO, 2,2,6,6-tetraethyl-1-piperidinyloxyl, 2,2,6-trimethyl-6-ethyl-1-piperidinyloxyl, N-tert-butyl 1-phenyl-2-methylpropyl nitroxide, N-tert-butyl 1-(2-naphthyl)-2-methylpropyl nitroxide, N-tert-butyl 1-diethylphosphono-2,2-dimethylpropyl nitroxide, N-tert-butyl 1-dibenzylphosphono-2,2-dimethylpropyl nitroxide, N-(1-phenyl-2-methylpropyl) 1-diethylphosphono-1-methylethyl nitroxide, di-t-butyl nitroxide, diphenyl nitroxide, and tert-butyl tert-amyl nitroxide. 
   
   
       26 . The method of  claim 24 , wherein the controlled polymerization is a variant of the RAFT polymerization, in which the trithiocarbonates TTC1 and TTC2 or the thio compounds THI1 and THI2 or the thioesters THE are used, φ 
     
       
         
         
             
             
         
       
     
     being an unfunctionalized phenyl group or a phenyl group functionalized with alkyl or aryl substituents attached directly or via ester or ether bridges, a functionalized phenyl group, functionalized preferably with halogen, hydroxyl, epoxy and/or nitrogen-containing or sulfur-containing groups, a cyano group or a saturated or unsaturated aliphatic radical, and where R $1  and R$ 2  are chosen independently of one another and R $1  can be a radical from one of groups i) to iv) below, and R$ 2  a radical from one of groups i) to iii) below:
 i) C 1  to C 18  alkyl, C 2  to C 18  alkenyl, C 2  to C 18  alkynyl, each linear or branched; aryl, phenyl, benzyl, aliphatic and aromatic heterocycles. 
 
     
       
         
         
             
             
         
       
       ii) —NH 2 , —NH—R $3 , —NR $3 R $4 , —NH—C(O)—R $3 —NR $3 —C(O)—R $4 , —NH—C(S)—R $3 , —NR $3 —C(S)—R $4 , where R $3  and R $4  are radicals selected independently of one another from group i). 
       iii) —S—R $5  or —S—C(S)—R $5 , R $5  preferably being a radical from one of groups i) or ii). 
       iv) — 0 —R $6  or —O—C(O)—R $6 , R $6  preferably being a radical from one of groups i) or ii). 
     
   
   
       27 . The method of  claim 24 , wherein the controlled polymerization is a variant of ATRP polymerization. 
   
   
       28 . The method of  claim 15 , wherein radical stabilization is effected using polymer-bonded or non-polymer-bonded nitroxides of the type (NIT 1) or (NIT 2): 
     
       
         
         
             
             
         
       
       where R #1 , R #2 , R #3 , R #4, R   #5 , R #6 , R #7  and R #8  independently of one another can denote the following groups: 
       i) halides, 
       ii) linear, branched, cyclic and heterocyclic hydrocarbons having 1 to 20 carbon atoms, which may be saturated, unsaturated or aromatic; 
       iii) —COOR #9  ,—OR #10  and —PO(OR #11 ) 2 , where R #9 , R #10  and R #11  stand for radicals from group ii). 
     
   
   
       29 . The method of  claim 15 , wherein crosslinkers selected from the croup consisting of metal chelates, isocyanates, amines, alcohols and epoxides are added. 
   
   
       30 . The method of  claim 15 , wherein the polymers are crosslinked by actinic radiation. 
   
   
       31 . The method of  claim 15 , wherein the polymers are crosslinked by UV radiation. 
   
   
       32 . A method for mounting printing plates to printing cylinders or sleeves which comprises mounting said printer Plates with the adhesive tape of  claim 1 . 
   
   
       33 . The method of  claim 21 , wherein said initiator having a grafting activity of ε>10 is bis(4-tert-butylcyclohexyl) peroxide dicarbonate or dibenzoyl peroxide.