Permanent adhesive

There are many obstacles to permanent adhesion under oral conditions. The substrate is a biological tissue and subject to change, and the presence of moisture represents the worst kind of situation for adhesion. Water is the great barrier to adhesion. It competes for the polar surface of tooth material against any potential polymer adhesive. It also tends to hydrolyse any adhesive bond formed. These twin obstacles gave rise to considerable doubt as to whether materials adhesive to tooth material could be developed at all (Cornell, 1961). 

Required on front folder in a clear, sharp, permanent-type print in black ink. Permanent adhesive labels may be used in a clear, sharp print. Printing must withstand a Scotch Tape Test, which consists of pressing a strip of Scotch tape firmly on the printed area and removing it. There should be no transfer of the printed area on the tape. 

After intimate contact is achieved between adhesive and adherend through wetting, it is believed that permanent adhesion results primarily through forces of molecular attraction. Four general types of chemical bonds are recognized as being involved in adhesion and cohesion electrostatic, covalent, and metallic, which are referred to as primary bonds, and van der Walls forces, which are referred to as secondary bonds. 

Attach graphs, charts, etc., to notebook pages with permanent adhesive. When unfolded, attached documents should be within the confines of the opened notebook. 

Pressure-sensitive adhesive Adhesive present in solvents or available as dispersion, which remains permanently adhesive after setting. 

Pressure-sensitive adhesives like those used on Post-It-Notes often contain the same adhesive material used in more permanent adhesives like Scotch Tape except in lesser amounts. 

The basic mechanism of tumble/growth agglomeration is shown in Fig. 6.1. Adhesion of individual particles to each other or to solid surfaces is controlled by the competition between volume and surface related forces (see also Section 5.4). To cause permanent adhesion, certain criteria must be fulfilled. The most important of all is that any system force (e.g. caused by gravity, inertia, drag, etc.) must be smaller than the attraction forces between the adhering partners. According to Fig. 6.2 and Equation 6.1, the ratio between the binding forces Bj(x) and the sum of the active components of all ambient forces F y(x) is a measure for the adhesion tendency T ... 

Permanent Adhesives—Provides high tack, ultraviolet resistance and strong ultimate adhesion. 

Permanent adhesion to a solid base. Among the higher animals there are, for example, the larvae of Plecoptera or macroscopic Ephydatia fluviatilis. Stones, wood, tree branches, tufts of plants, etc. can sei-ve as the substrate. 

A variety of different pressure-sensitive formulations are available, many of which have already been mentioned. Some formulations provide permanent adhesion. 

The invention of sticky notes occurred over a period of about 10 years and involved a great deal of serendipity. The adhesive for Post-it Notes was discovered by Dr. Spencer F. Silver of 3M in 1968. Silver found that when an acrylate polymer material was made in a particular way, it formed crosslinked microspheres. When suspended in a solvent and sprayed on a sheet of paper, this substance formed a sparse monolayer of adhesive after the solvent evaporated. Scanning electron microscope images of the adhesive show that it has an irregular surface, a little like the surface of a gravel road. In contrast, the adhesive on cellophane tape looks smooth and uniform, like a superhighway. The bumpy surface of Silver s adhesive caused it to be sticky but not so sticky as to produce permanent adhesion because the number of contact points between the binding surfaces was limited. 

Engineered pressure-sensitive laminates are formulated to adhere to specific substrates and can either be permanent or removable, depending on the end-use application. Permanent adhesives possess high ultimate adhesion to a variety of surfaces and are intended to last the lifecycle of the end-use product. Removable adhesives, on the other hand, are characterized by low ultimate adhesion to surfaces and are intended for applications that require... 

The use of anti-stripping agents applies both to surface dressings (Cawsey and Gourlet 1989 Woodside and Macoal 1989), where excellent and permanent adhesion is required, and to hot or cold bituminous mixtures (Anderson et al. 1982 Christensen and Anderson 1985). In both cases, the bitumen-aggregate adhesion is improved and the mixture resistance to the disastrous impact of water is increased, in case hydrophilic aggregates are used. 

WHEN PROPERLY INSTALLED, THIS SURFACE PROTECTED, PERMANENT ADHESIVE VINYL LABEL IS WEATHER RESISTANT AND DURABLE FOR REFERENCE BASED ON THE 12 MONTH ANNUAL VEHICLE INSPECTION REQUIREMENT. 

Pressure-sensitive adhesives (PSAs)— Adhesive materials which bond to adherend surfaces at room temperature immediately as low pressure is applied. Adhesives which require only pressure application to effect permanent adhesion to an adherend. 

Roth, J. Albrecht, V. Nitschke, M. Bellmann, C. Simon, F. Zschoche, S. Michel, S. Luhmann, C. Grundke, K. Voit, B., Self Functionalization of Silicone Rubber for Permanent Adhesion Improvement. Langmuir 2008,24, 12603-12611. 

Good wetting is very important in adhesive bonding. After intimate contact is achieved between the adhesive and adherend through wetting, it is believed that permanent adhesion resnlts primarily through forces of molecular attraction. 

Durable closures/fasteners merely require positioning on the fabric, pressing firmly, and it is done. No sewing, ironing, or messy glues are required. The permanent adhesive bond withstands laundering. These are used for low-profile knit drapes with fabrics. 

The story of Post-It Notes identifies 3M s organizing mode and illustrates how it works. In 1969, while Spencer Silver was conducting experiments in search of a more permanent adhesive, he stumbled upon a new substance - glue that did not glue. While Silver admired the structural properties of the new substance under a microscope, he could not imagine how it might be useful ... 

In contrast, the adhesive on cellophane tape looks smooth and uniform, like a superhighway. The bumpy surface of Silver s adhesive caused it to be sticky but not so sticky to produce permanent adhesion, because the number of contact points between the binding surfaces was limited. 

---