Laminates joined by polyurethane hot-melt adhesive and process for bonding plasticizer-containing plastics

Abstract

The present invention relates to laminates of a plasticizer-containing plastic, obtained by bonding by means of a moisture-reactive hot-melt adhesive which comprises at least one aldimine and at least one polyurethane polymer which contains isocyanate groups and is solid at room temperature. The bonded assembly is notable for improved adhesive, particularly following heat/moisture storage or alternating storage. Preferred embodiments of such laminates are bonded films or film-laminated supports, the film preferably being a pPVC film.

1 . Laminate having
 a) at least one substrate S 1 ;   b) at least one hot-melt adhesive K comprising   at least one polyurethane polymer P which contains isocyanate groups and is solid at room temperature, and   at least one aldimine A;   c) at least one substrate S 2 ,   the substrate S 1  and/or the substrate S 2  being a plasticizer-containing plastic, the substrate S 1  and/or the substrate S 2  having been pretreated, where appropriate, with a primer; and   the substrate S 1  being joined to the substrate S 2  via the hot-melt adhesive K.   
     
     
         2 . Laminate according to  claim 1 , wherein the substrate S 1  and/or the substrate S 2  is plasticized polyvinyl chloride (pPVC). 
     
     
         3 . Laminate according to  claim 1 , wherein that the substrate S 1  and/or the substrate S 2  is a polycarbonate (PC) or an acrylonitrile-butadiene-styrene copolymer (ABS) or a PC/ABS blend or a PC/ABS composite. 
     
     
         4 . Laminate according to  claim 1 , wherein the polyurethane polymer P which contains isocyanate groups and is solid at room temperature is prepared from at least one polyisocyanate and at least one polyol, more particularly a polyol which is solid at room temperature, preferably a polyester polyol which is solid at room temperature. 
     
     
         5 . Laminate according to  claim 1 , wherein the aldimine A has the formula (I-A) 
       
         
           
           
               
               
           
         
         where X P  is a polyamine having w primary amino groups following removal of w primary amino groups, 
         w is an integer 2-8, more particularly 2-4, preferably 2 or 3, 
         and Y is a radical of the formula (I a) or (I b) 
       
       
         
           
           
               
               
           
         
         where 
         Y 1  and Y 2  either 
         independently of one another are each a monovalent hydrocarbon radical having 1 to 12 C atoms, 
         or together are a divalent hydrocarbon radical having 4 to 20 C atoms which is part of an unsubstituted or substituted carbocyclic ring having 5 to 8, preferably 6, C atoms; 
         Y 3  is a monovalent hydrocarbon radical which where appropriate has at least one heteroatom, more particularly oxygen in the form of ether, carbonyl or ester groups; and 
         Y 4  either 
         is a substituted or unsubstituted aryl or heteroaryl group which has a ring size of 5 to 8, preferably 6, atoms, 
         or is 
       
       
         
           
           
               
               
           
         
         where R 1  is a hydrogen atom or an alkoxy group, 
         or is a substituted or unsubstituted alkenyl or arylalkenyl group having 1-30 C atoms. 
       
     
     
         6 . Laminate according to  claim 5 , wherein the polyamine deriving from the radical X P  is selected from the group consisting of 1,6 hexamethylenediamine, 1,5-diamino-2-methylpentane (MPMD), 1,3 diaminopentane (DAMP), 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (i.e. isophoronediamine or IPDA), 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 4-aminomethyl-1,8-octanediamine, 1,3- and 1,4-xylylenediamine, 1,3- and 1,4-bis(aminomethyl)cyclohexane, bis-(4-aminocyclohexyl)methane, bis-(4-amino-3-methylcyclohexyl)methane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6 ]decane, 1,2-, 1,3- and 1,4-diaminocyclohexane, polyoxyalkylene-diamines and -triamines, and also mixtures of two or more of the aforementioned polyamines. 
     
     
         7 . Laminate according to  claim 1 , wherein the aldimine A has the formula (I-B) 
       
         
           
           
               
               
           
         
         where 
         Q is the radical of a polyisocyanate containing (u+v) terminal isocyanate groups following removal of all the isocyanate groups; 
         u is 0 or 1 or 2; 
         v is 1 or 2 or 3; 
         s is 1 or 2, preferably 1; 
         Y is the radical of the formula (I a) or (I b) 
       
       
         
           
           
               
               
           
         
         where 
         Y 1  and Y 2  either 
         independently of one another are each a monovalent hydrocarbon radical having 1 to 12 C atoms, 
         or together are a divalent hydrocarbon radical having 4 to 20 C atoms which is part of an unsubstituted or substituted carbocyclic ring having 5 to 8, preferably 6, C atoms; 
         Y 3  is a monovalent hydrocarbon radical which where appropriate has at least one heteroatom, more particularly oxygen in the form of ether, carbonyl or ester groups; and 
         Y 4  either 
         is a substituted or unsubstituted aryl or heteroaryl group which has a ring size of 5 to 8, preferably 6, atoms, 
         or is 
       
       
         
           
           
               
               
           
         
       
       where R 1  is a hydrogen atom or an alkoxy group,
 or is a substituted or unsubstituted alkenyl or arylalkenyl group having 1-30 C atoms; 
 and 
 X either 
 is an (s+1)-valent hydrocarbon radical having preferably 2 to 20 C atoms and containing heteroatoms where appropriate, 
 or, if Z is N—R 7 , is together with R 7  an (s+2)-valent hydrocarbon radical having preferably 3 to 20 C atoms and containing, where appropriate, at least one heteroatom, more particularly in the form of ether oxygen or tertiary amine nitrogen; 
 Z is O, S, NH, NR 2  or NR 7 , 
 where R 2    
 either 
 is a monovalent hydrocarbon radical having 1 to 20 C atoms which where appropriate has at least one carboxylic ester, nitrile, nitro, phosphonic ester, sulphone or sulphonic ester group, 
 or 
 is a substituent of the formula (X) 
 
       
         
           
           
               
               
           
         
         where 
         n is 1 or 2, 
         R 8  is an (n+1)-valent hydrocarbon radical which where appropriate contains heteroatoms, more particularly in the form of ether oxygen or tertiary amine nitrogen, and contains, where appropriate, active hydrogen in the form of hydroxyl groups, secondary amino groups or mercapto groups; and 
         R 7  together with X is an (s+2)-valent hydrocarbon radical having preferably 3 to 20 C atoms which contains, where appropriate, at least one heteroatom, more particularly in the form of ether oxygen or tertiary amine nitrogen; 
         with the proviso that u+(v*s) has a value of ≧2. 
       
     
     
         8 . Laminate according to  claim 7 , wherein Q is a polyurethane polymer PUP containing (u+v) terminal isocyanate groups following removal of all of the isocyanate groups and is obtainable more particularly from the reaction of at least one polyol with at least one polyisocyanate, preferably of at least one diol and at least one diisocyanate. 
     
     
         9 . Laminate according to  claim 8 , wherein the polyurethane polymer PUP containing (u+v) terminal isocyanate groups is a polyurethane polymer PUP1 which contains isocyanate groups and is solid at room temperature. 
     
     
         10 . Laminate according to  claim 7 , wherein the amine deriving from the radical X is selected from the group consisting of N-methyl-1,2-ethanediamine, N-ethyl-1,2-ethanediamine, N cyclohexyl-1,2-ethanediamine, N-methyl-1,3-propanediamine, N-ethyl-1,3-propanediamine, N-butyl-1,3-propanediamine, N-cyclohexyl-1,3-propanediamine, 4-aminomethyl-piperidine, 3-(4-aminobutyl)piperidine, diethylenetriamine (DETA), bishexamethylenetriamine (BHMT), dipropylenetriamine (DPTA), fatty diamines, such as N-cocoalkyl-1,3-propanediamine, N-oleyl-1,3-propanediamine, N-soyaalkyl-1,3-propanediamine and N-tallowalkyl-1,3-propanediamine; 5-amino-1-pentanol, 6-amino-1-hexanol, 4-(2-aminoethyl)-2-hydroxyethylbenzene, 3 aminomethyl-3,5,5-trimethyl-cyclohexanol, 2-(2-aminoethoxy)ethanol, triethylene glycol monoamine, 3-(2-hydroxyethoxy)propylamine, 3-(2-(2-hydroxyethoxy)ethoxy)propylamine and 3-(6-hydroxyhexyloxy)propylamine. 
     
     
         11 . Laminate according to  claim 7 , wherein Z is NH and X is the radical of an asymmetric diamine having two primary amino groups following removal of these two amino groups. 
     
     
         12 . Laminate according to  claim 11 , wherein the asymmetric diamine is selected from the group consisting of 1,2-propanediamine, 2 methyl-1,2-propanediamine, 1,3-butanediamine, 1,3-diaminopentane (DAMP), 2,2,4-trimethylhexamethylenediamine (TMD), 1,5-diamino-2-butyl-2-ethylpentane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (i.e. isophoronediamine or IPDA) and 1,4-diamino-2,2,6-trimethylcyclohexane (TMCDA). 
     
     
         13 . Laminate according to  claim 5 , wherein Y is the radical of the formula (I a). 
     
     
         14 . Laminate according to  claim 5 , wherein Y 1  and Y 2  are each methyl. 
     
     
         15 . Laminate according to  claim 5 , wherein Y 3  is a radical of the formula (II) or (III), preferably a radical of the formula (III) 
       
         
           
           
               
               
           
         
         where R 3  is a hydrogen atom or is an alkyl or arylalkyl group, more particularly having 1 to 12 C atoms, preferably a hydrogen atom; 
         R 4  is a hydrocarbon radical having 1 to 30, more particularly 11 to 30, C atoms which where appropriate contains heteroatoms; and 
         R 5  either 
         is a hydrogen atom 
         or 
         is a linear or branched alkyl radical having 1 to 30, more particularly 11 to 30, C atoms, where appropriate with cyclic fractions and where appropriate with at least one heteroatom, 
         or 
         is a singly or multiply unsaturated, linear or branched hydrocarbon radical having 5 to 30 C atoms 
         or 
         is an unsubstituted or substituted, aromatic or heteroaromatic 5- or 6 membered ring. 
       
     
     
         16 . Laminate according to  claim 1 , wherein the hot-melt adhesive K is substantially free from plasticizers. 
     
     
         17 . Laminate according to  claim 1 , wherein the hot-melt adhesive K has been crosslinked under the influence of water, more particularly in the form of atmospheric moisture. 
     
     
         18 . Coated polymeric film obtained by applying a hot-melt adhesive K as described in a laminate according to  claim 1  in a melted state to a film of a plasticizer-containing plastic, more particularly to a pPVC film. 
     
     
         19 . Process for the adhesive bonding of a plasticizer-containing plastic, comprising the steps of
 i) melting a hot-melt adhesive K   ii) applying the melted hot-melt adhesive K to a substrate S 1     iii) contacting the surface of a substrate S 2  with the hot-melt adhesive K within its open time;   or   i′) melting a hot-melt adhesive K   ii′) applying the melted hot-melt adhesive K to a substrate S 1     iii′) cooling the hot-melt adhesive K to room temperature   iv′) melting the hot-melt adhesive K located on the substrate S 1     v′) contacting the surface of a substrate S 2  with the hot-melt adhesive K;   or   i″) melting a hot-melt adhesive K   ii″) applying the melted hot-melt adhesive K into a gap confined laterally substantially by the surfaces of the substrate S 1  and the substrate S 2 ;   at least one of the substrates S 1  or S 2 , being a plasticizer-containing plastic and the substrate S 1  being composed of the same material as or a different material to the substrate S 2 ;   and the hot-melt adhesive K comprising at least one aldimine A and at least one polyurethane polymer P which contains isocyanate groups and is solid at room temperature.   
     
     
         20 . Process according to  claim 19 , wherein step iii) or v′) or ii″) is followed by a step of crosslinking the hot-melt adhesive K by reacting the isocyanate groups with water, more particularly in the form of atmospheric moisture. 
     
     
         21 . Process according to  claim 19 , wherein the plasticizer-containing plastic is in the form of a film. 
     
     
         22 . Process according to  claim 19 , wherein the plasticizer-containing plastic is plasticized polyvinyl chloride (pPVC). 
     
     
         23 . Process according to  claim 19 , wherein both substrates, S 1  and S 2 , are plasticized polyvinyl chloride (pPVC). 
     
     
         24 . Process according to  claim 19 , wherein one of the two substrates, S 1  or S 2 , is plasticized polyvinyl chloride (pPVC) and the other of the two substrates, S 2  or S 1 , is a polycarbonate (PC) or an acrylonitrile-butadiene-styrene copolymer (ABS) or a PC/ABS blend or a PC/ABS composite. 
     
     
         25 . Process according to  claim 19 , wherein the polyurethane polymer P which contains isocyanate groups and is solid at room temperature is prepared from at least one polyisocyanate and at least one polyol, more particularly a polyol which is solid at room temperature, preferably a polyester polyol which is solid at room temperature. 
     
     
         26 . Process according to  claim 19 , wherein the aldimine A has the formula (I-A) 
       
         
           
           
               
               
           
         
         where X P  is a polyamine having w primary amino groups following removal of w primary amino groups, 
         w is an integer 2-8, more particularly 2-4, preferably 2 or 3, 
         and Y is a radical of the formula (I a) or (I b) 
       
       
         
           
           
               
               
           
         
         where 
         Y 1  and Y 2  either 
         independently of one another are each a monovalent hydrocarbon radical having 1 to 12 C atoms, 
         or together are a divalent hydrocarbon radical having 4 to 20 C atoms which is part of an unsubstituted or substituted carbocyclic ring having 5 to 8, preferably 6, C atoms; 
         Y 3  is a monovalent hydrocarbon radical which where appropriate has at least one heteroatom, more particularly oxygen in the form of ether, carbonyl or ester groups; and Y 4  either 
         is a substituted or unsubstituted aryl or heteroaryl group which has a ring size of 5 to 8, preferably 6, atoms, 
         or is 
       
       
         
           
           
               
               
           
         
       
       where R 1  is a hydrogen atom or an alkoxy group,
 or is a substituted or unsubstituted alkenyl or arylalkenyl group having 1-30 C atoms. 
 
     
     
         27 . Process according to  claim 26 , wherein the polyamine deriving from the radical X P  is selected from the group consisting of 1,6 hexamethylenediamine, 1,5-diamino-2-methylpentane (MPMD), 1,3 diaminopentane (DAMP), 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (i.e. isophoronediamine or IPDA), 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 4-aminomethyl-1,8-octanediamine, 1,3- and 1,4-xylylenediamine, 1,3- and 1,4-bis(aminomethyl)cyclohexane, bis-(4-aminocyclohexyl)methane, bis-(4-amino-3-methylcyclohexyl)methane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6 ]decane, 1,2-, 1,3- and 1,4-diaminocyclohexane, polyoxyalkylene-diamines and -triamines, and also mixtures of two or more of the aforementioned polyamines. 
     
     
         28 . Process according to  claim 19 , wherein the aldimine A has the formula (I-B) 
       
         
           
           
               
               
           
         
         where 
         Q is the radical of a polyisocyanate containing (u+v) terminal isocyanate groups following removal of all the isocyanate groups; 
         u is 0 or 1 or 2; 
         v is 1 or 2 or 3; 
         s is 1 or 2, preferably 1; 
         Y is the radical of the formula (I a) or (I b) 
       
       
         
           
           
               
               
           
         
         where 
         Y 1  and Y 2  either 
         independently of one another are each a monovalent hydrocarbon radical having 1 to 12 C atoms, 
         or together are a divalent hydrocarbon radical having 4 to 20 C atoms which is part of an unsubstituted or substituted carbocyclic ring having 5 to 8, preferably 6, C atoms; 
         Y 3  is a monovalent hydrocarbon radical which where appropriate has at least one heteroatom, more particularly oxygen in the form of ether, carbonyl or ester groups; and Y 4  either 
         is a substituted or unsubstituted aryl or heteroaryl group which has a ring size of 5 to 8, preferably 6, atoms, 
         or is 
       
       
         
           
           
               
               
           
         
         where R 1  is a hydrogen atom or an alkoxy group, 
         or is a substituted or unsubstituted alkenyl or arylalkenyl group having 1-30 C atoms; 
         and 
         X either 
         is an (s+1)-valent hydrocarbon radical having preferably 2 to 20 C atoms and containing heteroatoms where appropriate, 
         or, if Z is N—R 7 , is together with R 7  an (s+2)-valent hydrocarbon radical having preferably 3 to 20 C atoms and containing, where appropriate, at least one heteroatom, more particularly in the form of ether oxygen or tertiary amine nitrogen; 
         Z is O, S, NH, NR 2  or NR 7 , 
         where R 2    
         either 
         is a monovalent hydrocarbon radical having 1 to 20 C atoms which where appropriate has at least one carboxylic ester, nitrile, nitro, phosphonic ester, sulphone or sulphonic ester group, 
         or 
         is a substituent of the formula (X) 
       
       
         
           
           
               
               
           
         
         where 
         n is 1 or 2, 
         R 8  is an (n+1)-valent hydrocarbon radical which where appropriate contains heteroatoms, more particularly in the form of ether oxygen or tertiary amine nitrogen, and contains, where appropriate, active hydrogen in the form of hydroxyl groups, secondary amino groups or mercapto groups; and 
         R 7  together with X is an (s+2)-valent hydrocarbon radical having preferably 3 to 20 C atoms which contains, where appropriate, at least one heteroatom, more particularly in the form of ether oxygen or tertiary amine nitrogen; 
         with the proviso that u+(v*s) has a value of ≧2. 
       
     
     
         29 . Process according to  claim 28 , wherein Q is a polyurethane polymer PUP containing (u+v) terminal isocyanate groups following removal of all of the isocyanate groups and is obtainable more particularly from the reaction of at least one polyol with at least one polyisocyanate, preferably of at least one diol and at least one diisocyanate. 
     
     
         30 . Process according to  claim 29 , wherein the polyurethane polymer PUP is a polyurethane polymer PUP1 which contains isocyanate groups and is solid at room temperature. 
     
     
         31 . Process according to  claim 28 , wherein the amine deriving from the radical X is selected from the group consisting of N-methyl-1,2-ethanediamine, N-ethyl-1,2-ethanediamine, N cyclohexyl-1,2-ethanediamine, N-methyl-1,3-propanediamine, N-ethyl-1,3-propanediamine, N-butyl-1,3-propanediamine, N-cyclohexyl-1,3-propanediamine, 4-aminomethyl-piperidine, 3-(4-aminobutyl)piperidine, diethylenetriamine (DETA), bishexamethylenetriamine (BHMT), dipropylenetriamine (DPTA), fatty diamines, such as N-cocoalkyl-1,3-propanediamine, N-oleyl-1,3-propanediamine, N-soyaalkyl-1,3-propanediamine and N-tallowalkyl-1,3-propanediamine; 5-amino-1-pentanol, 6-amino-1-hexanol, 4-(2-aminoethyl)-2-hydroxyethylbenzene, 3 aminomethyl-3,5,5-trimethyl-cyclohexanol, 2-(2-aminoethoxy)ethanol, triethylene glycol monoamine, 3-(2-hydroxyethoxy)propylamine, 3-(2-(2-hydroxyethoxy)ethoxy)propylamine and 3-(6-hydroxyhexyloxy)propylamine. 
     
     
         32 . Process according to  claim 28 , wherein Z is NH and X is the radical of an asymmetric diamine having two primary amino groups following removal of these two amino groups. 
     
     
         33 . Process according to  claim 32 , wherein the asymmetric diamine is selected from the group consisting of 1,2-propanediamine, 2 methyl-1,2-propanediamine, 1,3-butanediamine, 1,3-diaminopentane (DAMP), 2,2,4-trimethylhexamethylenediamine (TMD), 1,5-diamino-2-butyl-2-ethylpentane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (i.e. isophoronediamine or IPDA) and 1,4-diamino-2,2,6-trimethylcyclohexane (TMCDA). 
     
     
         34 . Process according to  claim 26 , wherein Y is the radical of the formula (I a). 
     
     
         35 . Process according to  claim 26 , wherein Y1 and Y 2  are each methyl. 
     
     
         36 . Process according to  claim 26 , wherein Y 3  is a radical of the formula (II) or (III), preferably a radical of the formula (III) 
       
         
           
           
               
               
           
         
         where R 3  is a hydrogen atom or is an alkyl or arylalkyl group, more particularly having 1 to 12 C atoms, preferably a hydrogen atom; 
         R 4  is a hydrocarbon radical having 1 to 30, more particularly 11 to 30, C atoms which where appropriate contains heteroatoms; and 
         R 5  either 
         is a hydrogen atom 
         or 
         is a linear or branched alkyl radical having 1 to 30, more particularly 11 to 30, C atoms, where appropriate with cyclic fractions and where appropriate with at least one heteroatom, 
         or 
         is a singly or multiply unsaturated, linear or branched hydrocarbon radical having 5 to 30 C atoms 
         or 
         is an unsubstituted or substituted, aromatic or heteroaromatic 5- or 6 membered ring. 
       
     
     
         37 . Process according to  claim 19 , wherein the hot-melt adhesive K is substantially free from plasticizers. 
     
     
         38 . Article obtained by a process according to  claim 19 . 
     
     
         39 . Article according to  claim 38 , wherein the article is a support laminated with pPVC film.