GB644291A - Improvements in or relating to normally tacky and pressure-sensitive eucohesive adhesive and method of preparing the same, and the improved adhesive tape employing the improved adhesive - Google Patents

Abstract

Pressure sensitive tacky adhesive compositions comprise 100 parts of a synthetic rubbery polymer consisting of acrylate ester, vinyl ester and vinyl ether polymers having side chains of at least 4 carbon atoms linked to individual carbon atoms through an oxygen atom, and 2-15 parts of a compatible, oil-soluble heat-and-oil-reactive phenol-aldehyde resin. Up to 16 parts of a resinous tackifier, e.g. zinc resinate, rosin, ester gum, hydrogenated rosin terpene resin, may be added. Polymers specified are those obtained by polymerizing (1) 75 parts 2-ethylbutyl acrylate and 25 parts ethyl acrylate in aqueous solution and hardening with alum; (2) 425 parts vinyl butyrate and 2.13 parts di-isoamyl ethylene dimaleate in solution in 425 parts tert.-butyl alcohol with benzoyl peroxide as catalyst; (3) vinyl-n-butyl ether. The oil-soluble reactive phenol-aldehydes are obtained by reacting substituted phenols, e.g. p-tert.-amyl, p-tert.-butyl and p-phenyl phenols with formaldehyde, e.g. 1345 parts p-tert.-amyl-phenol are added to a cooled solution of 130 parts NaOH, 200 parts water and 1300 parts 37 per cent formaldehyde and the mixture reacted with gentle heating until the free formaldehyde is reduced to 1 per cent. The pH is then brought to 1-2 by addition of acid and the resin separated from the aqueous phase, washed and distilled under vacuum until a brittle resin is obtained. The following compositions are given: (1) 100 parts acrylate polymer, 5 parts TiO2, 5 parts phenol-aldehyde resin, 10 parts ester gum, 1 part Zn resinate, 300 parts heptane, 6 parts ethyl alcohol; (2) 84 parts cross-linked polyvinyl butyrate, 4.2 parts phenol resin, 2.5 parts Zn resinate; (3) 100 parts polyvinyl-n-butyl ether, 7.5 parts "Bakelite" (Registered Trade Mark) resin, 4 parts "Zitro" resin (pale Zn resinate), 450 parts toluol. The adhesives may be used for coating "Cellophane" (Registered Trade Mark) tape. The Specification as open to inspection under Sect. 91 included any synthetic rubbery polymer having active hydrogen groups, as shown by the following examples (Cancelled): (1) butadiene-styrene copolymer, ZnO, TiO2, and yellow pigment, ester gum, terpene resin, oil-soluble phenol-aldehyde resin, and heptane; (2) butadiene-isobutylene copolymer, terpene resin, hydrogenated methyl abietate, phenol resin and heptane; (5) as in (1) the terpene resin being replaced by a coumarone-indene resin; (7) and (8) polymerized chloroprene and polymerized methyl pentadiene, respectively, as the synthetic rubber. This subject-matter does not appear in the Specification as accepted.ALSO:Pressure-sensitive tacky adhesive compositions comprise 100 parts of a synthetic rubbery polymer consisting of acrylate ester, vinyl ester and vinyl ether polymers having side chains of at least 4 carbon atoms linked to individual carbon atoms through an oxygen atom, and 2-15 parts of a compatible, oil soluble heat-and-oil-reactive phenol-aldehyde resin. Up to 16 parts of a resinous tackifier, e.g. zinc resinate, rosin, estergum, hydrogenated rosin, terpene resin, may be added. Polymers specified are those obtained by copolymerizing (1) 75 parts 2-ethylbutyl acrylate and 25 parts ethyl acrylate in aqueous solution and hardening with alum; (2) 425 parts vinyl butyrate and 2.13 parts di-isoamyl ethylene dimaleate in solution in 425 parts tert-butyl alcohol with benzoyl peroxide as catalyst, and (3) vinyl-n-butyl ether. The oil soluble reactive phenol-aldehydes are obtained by reacting substituted phenols, e.g. p-tertamyl, p-tert-butyl and p-phenyl phenols with formaldehyde, e.g. 1345 parts p-tert-amylphenol are added to a cooled solution of 130 parts NaOH, 200 parts water and 1300 parts 37 per cent formaldehyde and the mixture reacted with gentle heating until the free formaldehyde is reduced to 1 per cent. The pH is then brought to 1-2 by addition of acid and the resin separated from the aqueous phase, washed and distilled under vacuum until a brittle resin is obtained. The following compositions are given: (1) 100 parts acrylate polymer, 5 parts TiO2, 5 parts phenolaldehyde resin, 10 parts ester gum, 1 part Zn resinate, 300 parts heptane, 6 parts ethyl alcohol; (2) 84 parts cross-linked polyvinyl butyrate, 4.2 parts phenol resin, 2.5 parts Zn resinate; (3) 100 parts polyvinyl-n-butyl ether, 7.5 parts "Bakelite" (Registered Trade Mark) resin, 4 parts "Zitro" (Registered Trade Mark) resin (pale Zn resinate), 450 parts toluol; the adhesives may be used for coating "Cellophane" (Registered Trade Mark) tape. The Specification as open to inspection under Sect. 91 included any synthetic rubbery polymer having active hydrogen groups as shown in the following examples (Cancelled): (1) butadiene-styrene, copolymer, ZnO, TiO2, and yellow pigment, ester gum, terpene resin, oil soluble phenol-aldehyde resin, and heptane; (2) butadiene-isobutylene copolymer, terpene resin, hydrogenated methyl abietate, phenol resin and heptane; (5) as in (1), the terpene resin being replaced by a coumarone-indene resin; (7 and 8) specify polymerized chloroprene and polymerized methyl pentadiene respectively as the synthetic rubber. This subject-matter does not appear in the Specification as accepted.