Лако-красочные материалы — производство

Whilst this might seem obvious, it is essential that there is sufficient adhesive to fill the joint. Joint starvation can often be the reason for poor joint strength. In some applications air voids and cavities can often mean the difference between a ‘good’ or ‘bad’ joint, especially if the adhesive is required to act as […]

In this chapter the failure modes of adhesives are discussed and some practical hints and tips are included to help identify and rectify the reason for the failure mode. There are a whole host of reasons as to why an adhesive might fail for a particular joint and the list below is not necessarily complete […]

There is usually very little accurate durability data available for the bonding of engineering plastics and it has to be admitted that the specialist adhesive engineers Environmental resistance 100 200 300 400 500 600 700 800 900 1000 Time (hours) Figure 9.8 Three possible results from an environmental test can usually only offer the design […]

Epoxies cure to become thermoset adhesives and so show excellent humidity resistance, especially if one of the substrates is metal. For long-term, durable adhesively bonded metal-to-metal joints, toughened epoxies are hard to beat [6] but where plastics are involved, some of the other technology adhesives invariably offer benefits in terms of ease of application and […]

Two-part acrylics will often show slightly improved durability over cyanoacrylates, particularly where the gaps are bigger and one of the substrates is not a plastic. However, two-part acrylics do not bond well to elastomers and here cyanoacrylates will show much better durability. For impact resistance and peel strength, the tougheners in two-part acrylics will be […]

Typical application areas for UV adhesives in the medical industry include the assembly of blood collection devices, endoscopes, hearing aids, IV sets, infusion pimps, catheters and diagnostic imaging equipment. The UV adhesive is often used to bond a stainless steel guide wire inside a polycarbonate luer or similar moulded part. Other applications include cannula/hub bonding, […]

The durability of UV-curing acrylic adhesives will again depend very much on the substrates bonded, the joint design and the gap between the parts. Some UV adhesives with silane additives are specifically formulated for the bonding of glass, whereas other UV-curing adhesives are best suited for plastics. UV adhesives generally will show good adhesion and […]

Cyanoacrylates are quite widely used for the bonding of medical devices (especially small component parts, see Figure 9.5) as these adhesives show excellent adhesion to many of the plastics used in this industry. In this industry component parts are sterilised and, whilst cyanoacrylates will withstand gamma sterilisation and ethylene oxide (EtO) sterilisation processes, they would […]

A significant point to consider when selecting an adhesive is its moisture resistance. For this reason, the technical data of an adhesive frequently lists the durability of bonds in humid environments after prolonged time periods. Normally charts are included that list the percentage of initial resistance retained by the adhesive bond over time under known […]

Joint design is discussed in more detail in Chapter 5 and can have an important influence on the durability of the joint so a few general points relating to durability are discussed here. Adhesive bond lines will always be susceptible to environmental attack and a thick bond line (>0.2 mm) offers a ready path for […]