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

A coated polymeric film obtained by applying a hot-melt adhesive K in a melted state to a film of a plasticizer-containing plastic, wherein the hot-melt adhesive K comprises at least one aldimine A and at least one polyurethane polymer P that contains isocyanate groups and is solid at room temperature, wherein

• the hot-melt adhesive K reduces a gradual loss of adhesion between the adhesive and the plasticizer-containing plastic as compared to a same hot melt adhesive that does not contain the at least one aldimine A,
• wherein the aldimine A has formula (I-A):
• wherein XP is a polyamine having w primary amino groups following removal of w primary amino groups.,
• w is an integer of from 2 to 8, and
• Y is a radical of formula (I a) or formula (I b):
• wherein Y1 and Y2 are either
• independently of one another, each a monovalent hydrocarbon radical having 1 to 12 C atoms, or
• together, a divalent hydrocarbon radical having 4 to 20 C atoms that is part of an unsubstituted or substituted carbocyclic ring having 5 to 8 C atoms:
• Y3 is a monovalent hydrocarbon radical that optionally has at least one heteroatom;
• and
• Y4 is either
• a substituted or unsubstituted aryl or heteroaryl group which has a ring size of 5 to 8 atoms, or
• wherein R1 is a hydrogen atom, an alkoxy group, or is a substituted or unsubstituted alkenyl or arylalkenyl group having 1 to 30 C atoms, and
• the polyurethane polymer P is prepared from at least one polyisocyanate and a mixture of at least one amorphous polyester diol with at least one polyester diol that is liquid at room temperature.

A process for 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 S1, and
• iii) contacting the surface of a substrate S2 with the hot-melt adhesive K within its open time;
• or
• i′) melting the hot-melt adhesive K,
• ii′) applying the melted hot-melt adhesive K to the substrate S1,
• iii′) cooling the hot-melt adhesive K to room temperature,
• iv′) melting the hot-melt adhesive K located on the substrate S1, and
• v′) contacting the surface of the substrate S2 with the hot-melt adhesive K;
• or
• i″) melting the hot-melt adhesive K, and
• ii″) applying the melted hot-melt adhesive K into a gap confined laterally substantially by the surfaces of the substrate S1 and the substrate S2;
• wherein at least one of the substrates S1 or S2 is a plasticizer-containing plastic;
• the substrate S1 is composed of the same material as or a different material to the substrate S2;
• the hot-melt adhesive K comprises at least one aldimine A and at least one polyurethane polymer P which contains isocyanate groups and is solid at room temperature,
• wherein the aldimine A has formula (I-A):
• wherein XP is a polyamine having w primary amino groups following removal of w primary amino groups;
• w is an integer of from 2 to 8:
• and
• Y is a radical of formula (I a) or formula (I b):
• wherein Y1 and Y2 are either
• independently of one another, each a monovalent hydrocarbon radical having 1 to 12 C atoms, or
• together, a divalent hydrocarbon radical having 4 to 20 C atoms that is part of an unsubstituted or substituted carbocyclic ring having 5 to 8 C atoms;
• Y3 is a monovalent hydrocarbon radical that optionally has at least one heteroatom;
• and
• Y4 is either
• a substituted or unsubstituted aryl or heteroaryl group that has a ring size of 5 to 8 atoms, or
• wherein R1 is a hydrogen atom, an alkoxy group, or is a substituted or unsubstituted alkenyl or arylalkenyl group having 1 to 30 C atoms;
• the hot-melt adhesive K reduces a gradual loss of adhesion between the adhesive and the substrate that is the plasticizer-containing plastic as compared to a same hot melt adhesive that does not contain the at least one aldimine A;
• and
• the polyurethane polymer P is prepared from at least one polyisocyanate and a mixture of at least one amorphous polyester diol with at least one polyester diol that is liquid at room temperature.