Patent ID: 11873429
Assignee: BOSTIK SA
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 9:
10. A hot-melt, pressure-sensitive adhesive composition comprising:
a) at least one polyurethane comprising at least two end functional groups T of following formula (I):
wherein Rv represents a hydrogen atom or a methyl radical and X represents —O— or —NR′N— with R′N representing a hydrogen atom or a linear or branched alkyl radical comprising from 1 to 20 carbon atoms;
b) at least one tackifying resin chosen from the following resins:
(b1) terpene/phenolic resins;
(b2) resins resulting from polymerization of a-methylstyrene, optionally followed by a reaction with at least one phenol;
(b3) polymeric resins resulting from mainly C9 aromatic fractions; and

c) at least one polymerization inhibitor;

wherein the polyurethane(s) (a):tackifying resin(s) (b) ratio by weight ranges from 4: 6 to 6: 4, and wherein the polyurethane (a) is obtained by a process comprising the following stages:
E1) preparing a polyurethane comprising at least two NCO end functional groups by polyaddition reaction:
i. of at least one diisocyanate chosen from the group consisting of toluene diisocyanate, meta-xylylene diisocyanate, isophorone diisocyanate, HDI allophanates and their mixtures;
ii. with at least one polyether diol having a number-average molecular weight (Mn) of greater than or equal to 4,000 g/mol, or with a mixture of polyether diol having a number-average molecular weight (Mn) of greater than or equal to 4,000 g/mol with a polyether triol having a number-average molecular weight (Mn) of greater than or equal to 2,000 g/mol;

E2) reacting the product formed on conclusion of stage E1) with at least one hydroxylated ester of acrylic acid of formula (II-1-1):

CH2═CH—C(═O)—O—CH2—CH2—OH,

in amounts such that the OH/NCO molar ratio (denoted r2) is less than or equal to 1.00.