Trim Applications

The new steel panels used in vehicles are not as heavy as in older cars but, being thinner, are not as strong. The use of PU windshield adhesive/sealants to replace the traditional butyl sealants has enabled the windshield to become a structural part of the vehicle because it supports the roof. OEM adhesives are typically one-component moisture-cured urethanes that take several hours to cure and give bonds with tensile shear strengths of 5-8 MPa. The products are pigmented black to give resistance to UV. After-market adhesives 

Mirrors are sealed into their housings with RTV silicones. Electrochromic (self-darkening) mirrors need specially formulated epoxy adhesive-sealants to prevent diffusion of moisture and air into the electrochemical cells inside the mirrors. 

Adhesives for most of these applications are traditionally not of the structural loadbearing type and their choice is often dictated by ease of handling and assembly. 

Historically, solvent-based contact adhesives such as polychloroprene were used, but have been phased out for environmental reasons. 

PSA are widely used to attach labels and decals. They are increasingly used for trim bonding, particularly in the form of two-sided tapes or transfer tapes. New PSA show good adhesion to polyolefin-based substrates. 

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The finishes produced have very good light fastness and corrosion resistance, and, unlike integral colour finishes, the shade is largely independent of the aluminium alloy and the anodic film thickness used. The whole range of shades can be produced on films as thin as 5 /im, so the finishes are also being used in trim applications. Many patents and publications in the electrolytic colouring field now exist and they have been reviewed by many authors . 

Interior trim applications are decorative coverings with mechanical, safety and aesthetic functions. They include ... 

Table 47 shows typical material and jH ocess conditions for Elastolit SR low-density SRIM systems (36), and Table 48 shows the general mechanical ju operties for an Elastolit SR low-density SRIM system for interior trim applications. Elastolit is a trade mark for BASFs SRIM system (36). 

Table 48 Approximate Mechanical Properties for an ElastoUt SR-Based Low Density SRIM System for Interior Trim Applications (with 13 wt % OCF Glass Mat Reinforcement of 1.5 mjt (36)...

Celotex Corp. (35) has commercialized foamed composites consisting of a urethane-modified isocyanurate foam and continuous-glass-strand mat. The trade name of the composite is Thermax. Some physical properties of Thermax are shown in Table 52. The physical properties of a low-density SRIM system of urethane-isocyanurate foam for interior-trim applications are shown in Table 48. 

Initial attempts to use aluminum for automotive trim were unsuccessful due to the corrosion behavior of the metal. It is therefore anodized for automotive trim applications to provide a protective oxide surface which acts as a barrier coating for corrosion pro tec tion. > 2 Aluminum and its alloys are susceptible to pitting and crevice corrosion in chloride containing environments. The corrosion resistance of anodized aluminum is therefore highly dependent on the quality of the anodized surface and the absence of scratches and other damage sites. 

Solution Short- and long-glass-flber-relntorced PP for both structural and visible-trim applications. 

Other laser-materials interactions applied in the electronics industry involve the unique ability of laser light to be focused to very small areas and to heat only the areas irradiated. This allows lasers to serve a wide range of resistor and capacitor trimming applications. Also, when properly focused, lasers are able to remove unwanted bridges in microcircuits. If the atmosphere above the substrate is selected to form desired deposits when the substrate or the gas is heated, then lasers can be used to personalize microcircuit masks and to repair damaged circuits. Work with ultraviolet lasers may make it possible... 

In interior trim applications, impact copolymers with melt flow rates in the range of 20-35 g/10 min are most often seen, and they can be CR or reactor... 

In a flexible PVC compound the trimellitates are less volatile and have improved thermal stability over the phthalate and polymeric plasticizers. Their plasticizing effectiveness and compatibility are similar to phthalates. They offer better moisture and water resistance than the phthalates or polymeric plasticizers. Large volumes of trimellitate esters are used in 90°C and 105°C UL rated insulation compounds. Because of their extraction and migration resistance, thermal stability, and low volatility, the trimellitates are used in conjimction with 9IIP and DUP in automotive interior trim applications where windshield fogging is an issue. 

Decorative films for lamination to surfaces automotive trim applications aircraft interior surfaces in-mold lining processes (84)... 

General Motors commercialized the first exterior trim application of nanocomposite in their 2002 mid-sized vans. The part was stiffer, lighter, and less brittle in cold temperatures and more recyclable. Molded of a thermoplastic olefin clay nanocomposite, it offers weight savings and improved surface quality. About 540,000 Ibs/yr... 

In internal trim, many hard-trim applications are moving from plastics such as ABS toward TPO as the material of choice for performance and cost reasons. In addition to penetrating the hard-trim components, TPO are also moving into instrument panel skins (replacing vinyl) and into airbag covers (replacing urethane and... 

Interior trim applications encompass components such as door skins A, B, and C pillars as well as center consoles and add-on bezels. Several plastic types are utilized, with the majority of the applications now seeking lower cost through the use of mold-in-color polyolefins. 

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