The present invention relates to a process for bonding substrates, wherein the bond is a bond that can be released by heat treatment at a temperature of 50° C. to less than 200° C. and a composition is used to produce the bond, said composition containing a polymer of formula (I): Q-(O—C(O)—CR′R″—C(O)—R)x, where: Q=a polymer group, selected from a polyester group and/or a polyolefin group, wherein the polymer group does not contain any components that result from the use of molecules having (meth)acrylic acid units as monomers; x is greater than or equal to 1; R1═R2 or O—R3; R2=a hydrocarbon group, which can be substituted with halogen atoms, comprising 1 to 10 carbon atoms; R3=a hydrocarbon group, which can be substituted with halogen atoms, comprising 1 to 10 carbon atoms, or a polymer group; R′=—H, or a hydrocarbon group, which can be substituted with halogen atoms, comprising 1 to 10 carbon atoms, or a group of formula (II): —C(O)—NH-Q′, where Q′=an organic group which can also have one or more silicon atoms; and R″=—H or a group of formula (II), with the proviso that if neither of the groups R′ and R″ is a group of formula (II), then at least one of the groups R′ or R″ is —H.