Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
2001-01-22
2003-04-29
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S3550EN, C428S3550AC, C428S343000, C156S345420, C156S332000, C156S327000, C524S056000, C524S058000
Reexamination Certificate
active
06555217
ABSTRACT:
The invention relates to a support-free pressure-sensitively adhesive shaped article having a glass transition temperature of less than 10° C. which comprises a binder and a nonionic surfactant or a mixture of two or more nonionic surfactants, the binder present comprising an addition polymer or addition copolymer. The invention further relates to a process for producing such support-free, pressure-sensitively adhesive shaped articles and to the use of nonionic surfactants for adjusting the bond strength of a pressure-sensitively adhesive shaped articles.
For the decorative or functional outfitting of spaces for private or commercial use, one frequent task is to fasten information materials of paper or relatively lightweight functional articles, of metal, glass or plastic, for example, to vertical, inclined or horizontal surfaces, for example, to tables, cupboards or walls, in a durable but redetachable fashion. Whereas with heavy and compact articles which exceed a weight of about 1 kg, for example, mechanical fastening in the form of screws or nails, for example, is generally indispensable, there are various methods appropriate for the fastening of relatively lightweight paper articles, in the form of webs or sheets, for example.
For instance, thumbtacks or adhesive tapes with a pressure-sensitive adhesive coating on one or two sides are frequently used for the fastening of paper articles, examples being wall-mounted calendars, posters, photographs and the like. In practice, however, such fastening methods are frequently accompanied by disadvantages. Thumbtacks, for example, leave behind unsightly holes on the surfaces selected for the fastening, these holes generally having to be eliminated again following removal of the fastened article in order to re-establish the original visual appearance of the surface selected for fastening. This form of fastening has the further disadvantage that when used to fasten materials in web or sheet form which have a relatively high weight per unit area, examples being posters or calendars, a frequent occurrence is that the fastening is torn out at at least one fastening point, especially if the fastened article is subjected, deliberately or otherwise, to a load.
The use of adhesive strips with a pressure-sensitive adhesive coating has great disadvantages in particular when this fastening form is employed on papered walls. In general, the tensile strength and tensile shear strength of the pressure-sensitive adhesives are so great that the removal of the adhesive tape from the wall in question frequently entails removal of parts of the wallpaper as well, either leaving the wall with an unsightly overall appearance or requiring remedy by wallpapering or at least—possibly colored—covering of the area thus damaged.
For example, DE-C 43 19 023 describes a pressure-sensitive, carrierless, double-sidedly self-adhesive tape and the use of a polyacrylate pressure-sensitive adhesive for its production.
The tape is described, for example, for the durable fastening of photographs to different substrates such as Plexiglass, aluminum, polystyrene, PVC or paper. Importance is attached merely to the redetachability from specially siliconized films: redetachability from paper is not envisaged and is not mentioned. DE-A 28 04 942 relates to a process for producing crosslinked pressure-sensitive adhesive films from aqueous polymer emulsions or polymer dispersions. In this case, aqueous polymer emulsions or polymer dispersions which after drying give a self-adhesive film with good adhesion to the substrate are admixed with a water-soluble polyacrylic hydrazide crosslinking agent, the mixture obtained is applied to a flexible substrate, which may consist, for example, of paper, fiber nonwoven, a woven fabric or a film of plastic or modified natural material, and the applied mixture is crosslinked on this substrate by brief heat exposure at a temperature of from 60 to 160° C.
WO 97/14510 relates to water-based adhesives which comprise microbeads. The document describes a water-based adhesive composition which comprises a mixture of an aqueous concentrate of solid, self-adhesive, elastomeric, polymeric microbeads, an aqueous, acrylic-based pressure-sensitively adhesive binder, from 0.01 to 5% by weight of a surfactant and from 0.01 to 3% by weight of a viscosity modifier. The adhesive compositions described feature asymmetric distribution of the bond strength and the surfactants they comprise may include nonionic surfactants.
DE-A 33 19 78 describes the use of the reaction products of ethylene oxide with aliphatic vicinal diols as emulsifiers for emulsion polymerization. The use is described of ring opening products of 1,2-epoxyalkanes with ethylene glycol, which have been subsequently reacted with ethylene oxide, in the emulsion polymerization of compounds having an olefinically unsaturated double bond.
DE-T 693 09 202 (corresponding to EP-B 0 587 332) relates to an acrylic sealing compound which comprises an acrylic emulsion copolymer binder having a glass transition temperature of from about 0 to about −60° C., zinc oxide and solid silicon dioxide. The document mentions sealing compounds which comprise a nonionic surfactant based on octylphenol.
Adhesive tapes which are also intended to be redetachable from sensitive surfaces frequently comprise a large amount of low molecular mass plasticizers. When such adhesive tapes are put to long-term use on absorbent surfaces, they often leave behind marks and discolorations on the substrate in question, owing to the migration of the plasticizer molecules. Although such adhesive tapes circumvent the mechanical destruction of the substrate at the time of fastening or of detachment, they nevertheless leave the fastening site in a usually unsightly state. Where such adhesive tapes are additionally colored, for decorative purposes, a further frequent observation is migration of the dye into the bonded material, further intensifying the unattractive overall appearance of the former fastening site following detachment. There is therefore a need for a pressure-sensitively adhesive shaped article which does not have the abovementioned disadvantages. In particular, there was a need for a pressure-sensitively adhesive shaped article which permits durable fastening of even relatively heavy articles on surfaces of a very wide variety of types and with vertical, inclined or horizontal orientation. Furthermore, there was a need for pressure-sensitively adhesive shaped articles which are redetachable from a wide variety of surfaces and which following detachment may be used again for the durable fastening of articles. There was a need, moreover, for pressure-sensitively adhesive shaped articles which in the case of falling bond strength may be reset to the original bond strength, or at least to a value close to the original bond strength, by simple cleaning. Moreover, there was a need for pressure-sensitively adhesive shaped articles which following detachment, even after long-term use for fastening, cause no marking or discoloration of the substrate or of the fastened object.
It was therefore an object of the present invention to provide a pressure-sensitively adhesive shaped article which meets the needs described above. It was also an object of the present invention to provide a pressure-sensitively adhesive shaped article production process which leads to pressure-sensitively adhesive shaped articles which meet the above needs. Moreover, it was an object of the invention to provide a method which permits the bond strength of pressure-sensitively adhesive shaped articles to be adjusted within a wide range.
The abovementioned objects are achieved by means of a support-free pressure-sensitively adhesive shaped article which has a glass transition temperature of less than 10° C. and comprises at least one binder and a certain amount of an aliphatic or cycloaliphatic nonionic surfactant.
The invention accordingly provides a support-free pressure-sensitively adhesive shaped article having a glass transition temperature of less tha
Kuhn Joerg
Mueller Wolf-Ruediger
Peters Bernd W.
Dawson Robert
Harper Stephen D.
Henkel Kommanditgesellschaft auf Aktien
Keehan Christopher
Murphy Glenn E. J.
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