Polyurea systems, processes for preparing the same and use thereof for postoperative adhesion barriers

A process for preparing a polyurea system, the process comprising:

• (i) providing (a) an amino-functional aspartic ester of the general formula (I)
• wherein
• X is an n-valent organic radical having 2 to 5 carbon atoms,
• R1 and R2 each independently represent an organic radical having no Zerevitinov active hydrogens and n represents an integer of at least 2;
• (ii) providing (b) an isocyanate functional prepolymer having a residual monomer content of less than 1% by weight, the prepolymer prepared by reacting:
• (b1) an aliphatic isocyante;
• and
• (b2) a polyol component comprising:
• a polyether polyol which has a number-average molecular weight of 100 to 2,000 g/mol;
• and
• a polyol component comprising one or more constituents selected from the group consisting of polyester polyols, polyester-polyether polyols and mixtures thereof having a number average molecular weight of ≥400 g/mol and an average OH functionality of 2 to 6;
• wherein the ether groups are derived from, 60% to 90% of ethylene oxide units, based on the amounts of alkylene oxide units that are present in total;
• (iii) providing (c) an organic filler comprising a hydroxy-functional polyether polyol compound having a DIN 53019 viscosity at 23° C. of 10 to 6000 mPas;
• and wherein the (c) organic filler is mixed with the (a) amino-functional aspartic ester and the (b) isocyanate functional prepolymer at a weight ratio of organic filler to amino-functional aspartic ester of 0:1 to 20:1;
• and
• (iv) mixing the (a) amino-functional aspartic ester and the (b) isocyanate functional prepolymer in a ratio of free or blocked amino groups to free NCO groups of 1:1.

A dispensing system comprising a first chamber and a second chamber;

• wherein the first chamber comprises (a) an amino-functional aspartic ester of the general formula (I)
• wherein
• X is an n-valent organic optionally branched or cyclic organic radical having 2 to 5 carbon atoms,
• R1 and R2 each independently represent an organic radical having no Zerevitinov active hydrogens and n represents an integer of at least 2;
• and wherein the second chamber comprises (b) an isocyanate functional prepolymer having a residual monomer content of less than 1% by weight, the prepolymer prepared by reacting:
• (b1) an aliphatic isocyante;
• and
• (b2) a polyol component comprising:
• a polyether polyol which has a number-average molecular weight of 100 to 2,000 g/mol;
• and
• a polyol component comprising one or more constituents selected from the group consisting of polyester polyols, polyester-polyether polyols and mixtures thereof having a number average molecular weight of ≥400 g/mol and an average OH functionality of 2 to 6;
• wherein the ether groups are derived from, 60% to 90% of ethylene oxide units, based on the amounts of alkylene oxide units that are present in total.