Лако-красочные материалы — производство

Perhaps one of the most fundamental and key properties associated with the selection of the adhesive is to make sure that it bonds well to the two materials selected. Cyanoacrylates generally have good affinity to plastics and a good number of ultraviolet (UV) adhesive grades are also particularly suited for plastics, whilst other UV adhesives (with silane additives) are more suitable for glass — the product data sheet should be studied carefully to ensure compatibility with both adherends. Epoxies are good general-purpose products and can show excellent adhesion but are slower cure.

Some guidelines as to the tensile shear performance on plastics and elastomers with a number of different adhesives are given in Sections 2.2, 3.2 and 4.2 but adhesive strengths are very dependent on the joint design and the thicknesses of the adherends.

For example, polyethylene terephthalate (PET) plastic can be bonded with many different types of adhesives, including cyanoacrylates, UV acrylics and epoxies, and good strengths can be obtained on standard lap shear parts (1.6 mm thick). However, if thin films (<0.75 mm thick) of PET are to be bonded then it will be much easier to subject the adhesive to a peel load and the measured strength of the adhesive on the same grade of PET will be considerably lower.

The toughened adhesives will show improved peel strength (see Section 1.1.1.5) but note that the peel strength of an adhesive will generally be less than 10% of the nominal shear strength and could be as low as 1%.

Impact resistance is often a key requirement for components operating under dynamic stresses but this property is not usually quoted by adhesive manufacturers as the joint design, materials bonded and type of loading will all affect the impact strength performance. Toughened or flexible adhesives would generally be expected to show improved impact resistance and the highly crosslinked toughened epoxy­based adhesives are often the material of choice for applications where high impact loads are present.