Polymer film with multiphase film morphology

The polymer film according to either of the preceding claims, wherein the glass transition temperature of the first polymer is in the range from −60° C. to less than or equal to −10° C. and the glass transition temperature of the second polymer is in the range from −50° C. to less than or equal to 10° C., and

• the glass transition temperature of the second polymer is at least 2° C. greater than the glass transition temperature of the first polymer.

The polymer film according to any of the preceding claims, wherein the weight fraction of the tackifier in the polymer film is at least 20% greater in the regions of the first polymer than the weight fraction of the tackifier in the regions of the second polymer.

The polymer film according to any of the preceding claims, wherein the tackifier is selected from the group consisting of natural-resin-based tackifiers, phenolic resins, coumarone-indene resins, polyterpene resins, terpene oligomers, and hydrocarbon resins based on unsaturated CH compounds.

The polymer film according to any of the preceding claims, wherein the first polymer and the second polymer are obtainable by free-radical polymerization of ethylenically unsaturated compounds and are composed to an extent of at least 60% by weight of principal monomers which are selected from C1 to C20 alkyl (meth)acrylates, vinyl esters of carboxylic acids comprising up to 20 C atoms, vinylaromatics having up to 20 C atoms, ethylenically unsaturated nitriles, vinyl halides, vinyl ethers of alcohols comprising 1 to 10 C atoms, aliphatic hydrocarbons having 2 to 8 C atoms and one or two double bonds, or mixtures of these monomers, the nature and amount of the monomers being adjusted such that the glass transition temperature of the second polymer is at least 2° C. greater than the glass transition temperature of the first polymer.

The polymer film according to the preceding claim, wherein the first polymer and the second polymer are each composed to an extent of at least 60% by weight of C1 to C10 alkyl (meth)acrylates.

The polymer film according to any of the preceding claims, wherein the second polymer has a higher degree of crosslinking than the first polymer, and/or the monomer mixture from which the second polymer is formed comprises a higher fraction of polyunsaturated crosslinking monomers than the monomer mixture from which the first polymer is formed.

The polymer film according to the preceding claim, wherein the crosslinking monomers are selected from divinylbenzene, alkanediol diacrylates, alkanediol dimethacrylates, allyl acrylates and allyl methacrylates.

The polymer film according to any of the preceding claims, which is a pressure-sensitive adhesive.

The polymer film according to any of the preceding claims, wherein the maximum solubility of the tackifier in the phase of the first polymer is at least 20% greater than the maximum solubility of the tackifier in the phase of the second polymer.

The process according to the preceding claim, which is a process of adhesively bonding two substrates, the first substrate, following the application of the aqueous dispersion, being contacted with a second substrate, and an adhesive bond being produced between the two substrates.