Лако-красочные материалы — производство

Richard D. Rich Loctite Corporation, Rocky Hill, Connecticut, U. S.A. I. INTRODUCTION Anaerobic adhesives are mixtures of acrylic esters that remain liquid when exposed to air but harden when confined between metal surfaces. These mixtures can be used for a large number of industrial purposes, such as locking threaded fasteners, sealing threaded pipe connections, retaining […]

Worldwide use and sales for acrylic adhesives of the types discussed here are difficult to determine, particularly since so many of the chemistries involved are nowadays hybrids of more than one type. Acrylics would, no doubt, not be considered the major chemical family of adhesives, when compared to epoxies and urethanes. Nevertheless, due to the […]

A separate class of acrylic adhesives, not always listed with this family of materials, is the systems that will cure via exposure to light of various wavelengths. Of most interest are the ultraviolet (UV) radiation (below 300 nm wavelength) and, to some extent, the visible range (400 to 700 nm wavelength). These types of adhesives […]

A disadvantage of many acrylic adhesive products on the market today is that those that require mixing may require an awkward mix ratio. The first generation products, for instance, generally required a mix of 20 parts adhesive to 1 part curing agent, making highly automated production very difficult to achieve effectively. As the various genera­tions […]

Another advancement in acrylic adhesives has been in the area of acrylics with improved low temperature properties, sometimes called ‘‘HI’’ or ‘‘high impact’’ acrylics. These variants of the technology not only offer outstanding low temperature properties, but also significant heat resistance makes them ideal for applications where product perfor­mance over a wide temperature range is […]

The emergence of the DH acrylic adhesives occurred concurrent with the introduction of the so-called ‘‘HP’’ or ‘‘high performance” acrylic adhesives. This type of system, as with the DH types, offered users the ability to bond through oily metals, but did not require the use of awkward oily primers. They also were based on formulations […]

‘‘Conventional’’ or ‘‘first generation’’ acrylic adhesives are the earliest examples of this technology. They contain methacrylated monomers, a variety of polymers, an Table 1 Conventional, or First Generation, Acrylic Adhesives Component Parts by weight Styrene-methyl methacrylate copolymer syrup 40 Methacrylic acid 9 Poly(methyl methacrylate) syrup 49 Accelerator-stabilizer package 2 Table 2 Bond Performance of First […]

Acrylic adhesives, like many other adhesive types on the market today, have had a series of technical improvements often referred to as “generations” or ‘‘families.’’ These so-called ‘‘generations’’ of acrylic adhesives originally did represent fundamental changes in the formulations and significant improvement options to potential users. In recent years, these distinctions have been blurred considerably. […]

The polymerization of acrylic adhesives via free radicals (chain reaction) allows acrylic adhesives to be dispensed and cured using unique techniques. Other types of adhesive products often cure by condensation polymerization reactions which dictate certain cure characteristics and handling techniques. Different curing possibilities for acrylics follow from the fact that the free radicals, once formed, […]

As has been noted above, in order for adhesive systems containing methacrylated monomers to cure, a free radical must be generated. A typical means of generating afree radical is shown in Fig. 3. This method of initiating the cure of acrylic adhesives is also known as a redox reaction. Redox reactions for acrylics typically involve […]