Patent ES-8603929-A1 (ES)
Title: Self-adhesive flat items, method of making them and their use.
IPC: C09J7/38
Filed: 1984-11-13
Abstract: Self adhesive surface structure consists of a carrier layer and an adhesive layer at least partly coated with a gel as the adhesive surface. The gel is based on (A) 15 - 62 wt.%, pref. 20 - 57, and esp. 25 - 47 wt.% of a covalent crosslinked polyurethane as the high mol. wt. matrix and (B) 85-38 wt.%, pref. 80 - 43, and esp. 75 - 53 wt.% of one or more polyhydroxy cpds. bound by secondary valencies in the matrix, with an average mol. wt. between 1000 and 12000, and an average OH no. =20 - 112 as liq. dispersing agent, and in which, in the substantially free state the dispersing agent has a mol. wt. below 800, pref. under 1000, and partic. below 1500, and (C) 0 - 100% fillers and other additives. - The hydroxy cpd. which in the substantially free state has a mol. wt. below 800, the average functionality of the polyisocyanate (F1) is pref. between 2 and 4, the average functionality of the polyhydroxy cpd. (Fp) is at least 3 and the isocyanate (K) is governed by the formula (I) in which X is less than or = 120, pref. less than or = 90. The gel is produced during or after a direct or conversion process on the surface of the carrier material. A process for the prodn. of self-adhesive surface structures as claimed above. Use of the surface structures as medical plaster, for binding tapes, repair material, adhesive strips, or insect traps is claimed. - Good skin tolerance for medical uses with no residues after removal. The plasters are easily removed and their is no skin reaction. Wound cushioning can be achieved with the use of foamed polymers e.g. polyurethane, PVC or polyethylene. The materials adhere well to uneven surfaces and are useful for marking and signs, educational materials, insect traps, protective foils for automobile windows and stationery. (0/0) EPAB- EP-147588 B Self-adhesive sheet-like structures containing at least one support layer and at least one adhesive layer at least one of the two surfaces of the sheet-like structure being at least partially covered with an adhesive layer, characterised in that this adhesive layer is a gel which contains (A) 15-62% by weight, relative to the total of and (B), of a covalently crosslinked polyurethane as the high molecular weight matrix and (B) 85-38% by weight, relative to the total of (A) and (B) of one or more polyhydroxy compounds which are firmly fixed in the matrix by secondary valence forces and have an average molecular weight between 1,000 and 12,000, and an average OH number between 20 and 112, as a liquid dispersing agent, the dispersing agent being essentially free of hydroxy compounds having a molecular weight below 800, and, (C) 0-100% by weight relative to the total of (A) and (B), of fillers and/or additives, and which can be obtained by reaction of a mixture of (a) one or more polyisocyanates, (b) one or more polyhydroxy compounds having an average molecular weight between 1,000 and 12,000 and an average OH number between 20 and 112, (c) where appropriate, catalysts for the reaction between isocyanate and hydroxyl groups and, where appropriate, (d) fillers and additives which are known per se from polyurethane chemistry, this mixture being essentially free of hydroxy compounds having a molecular weight below 800, the average functionality of the polyisocyanates (F1) being between 2 and 4, the average functionality of the polyhydroxy compound (Fp) being between 3 and 6, and the isocyanate number (K) obeying the formula (I) in which X up to 100, and particularly preferably X up to 90 and the number K is between 15 and 70.  (12pp) USAB- US4661099 A Novel adhesive sheet structure comprises 1 or more support layer and 1 or more adhesive layer, 1 of which is at least partially covered with an adhesive layer which is a gel. - Gel comprises (a) 15-62 wt.% of covalently crosslinked polyurethane as a high mol. wt. matrix; and (b) 85-38 wt.% of 1 or more polyhydroxy cpd. immobilised in (a) by van der Wall's forces, having mol. wt. 1,000-12,000 and OH-value 20-112 which serve as a liq. dispersing agent contg. no OH cpd. less than mol.wt. 800; and (c) 0-100 wt.% of fillers and/or additives (each w.r.t. (a) + (b)). Gel  is obtd. by reacting a mixt. of (i) 1 or more polyisocyanate, and (ii) 1 or more polyhydroxy cpd. of mol. wt. 1000-12,000 and OH-value 20-112; and opt. (iii) catalyst for the reaction; and (iv) fillers and additives. Mixt. has no OH-cpd. of mol.wt. less than 800.