Underbody sealants

Nouybond 266 [Air ProdsJPerf. Chems.j Chem. Deserp. Modified polyamidoamine Uses PVC plastisol adhesion promoter for automotive sealants, underbody coatings, and anti-chip primers adhesion promoter for electrodeposition primers used in mfg. of automobiles, tmcks, and buses Features 120 C cure exc. color stabilily Properties Amber clear liq. vise. 5-20 poise amine no. 110-135 Use Level 1-2 parts... 

The hot dip process is used to coat wire baskets, brackets etc., and depends on preheating the object to be coated (100-120 °C) and dipping it into the plastisol where the PVC gels around the object. Cold dip and spray coating is used on fabrics, such as lined gloves, or metal, such as underbody sealant. These are subsequently gelled in an oven. The use of an infrared system to cure PVC sealant compound has also been introduced (343). 

Apart from underbody coating (usually PVC based), which is not explained further, the majority of bonding and sealing products in the paint shop are also PVC compounds. Acrylate plastisols are not often used and polyurethane-based sealants are rarely found. The main applications are in seam sealing and antiflutter bonding. On a small scale there are adhesive applications to bond and seal caps and to fix sound deadeners. In addition, foams and butyls as well as bituminous or acrylic-based sealants are used to fill car body holes. 

Typical products automotive underbody coatings and seam sealants, can coating, cap closures, carpet tiles, coated fabrics, floor coverings, gloves, insect and shade screening, mechanically expanded foams, toys ... 

Sealant applications are major commercial products, which fall into two categories PVC plastisols whieh do not have reactive components and PVC plastisols combined with blocked isoeyanates or isocyanurates. The first category of sealants is the most popular as an underbody sealant, whereas the seeond category includes construction and general purpose sealants. PVC gels are used occasionally as electrolytes, vibration reducing materials, and the like. 

Underbody sealant and coating. [Datafrompvc/acryiics plastisols. /vav.]... 

Automotive underbody sealant. [Data from Buess, P, Caers, R F, Colle, K S, Godwin, A, Saleh, R Y, Stanat, J E R, Less, D, European Patent EP2268727, Jan. 5, 2011, ExxonMobil Chemical Patents Inc.]... 

PVC underbody sealant. [Data from Godwin, A D, Gosse C, European Patent... 

Uses Extender for plastics, coatings, adhesives, sealants, patching compds., automotive underbody coatings, modeling clays, building materials, explosives, foams, textile printing inks, paper mfg., carpets, syn. wood, roof coatings, polymer concrete, wire and cable, cosmetics, pharmaceuticals... 

Uses Extender for plastisol and asphaltic underbody coatings, high mil-build industrial maintenance coatings, adhesives, spackles, caulks, sealants, high temp.-resist. cementitious and plastics composites Features Lightweight... 

Chem. Descrip. Modified poiyamidoamine Uses PVC plastisol adhesion promoter for automotive sealants and underbody coatings adhesion promoter for electrodeposition primers used... 

Chem. Descrip. Dicyclohexyl phthalate CAS 84-61-7 EINECS/ELINCS 201-545-9 Uses Plasticizer for delayed-tack heat-sealable coatings and adhesives PVC processing aid to reduce paste vise, in automotive underbody sealants gellant for PVC... 

In addition to these major market segments, plasticizers are used in a variety of smaller segments. Adhesives and sealants generally use lower molecular weight phthalate esters, benzoate esters and diesters, and dibutyl terephthalate because of improved solvency and lower fusion temperatures. One major use of plasticized PVC is automotive underbody coatings these products are highly filled plastisols that are mostly commonly based upon GP plasticizers often with a fast fusing plasticizer added to improve processability however, plasticizer volatility can be a major concern. 

Underbody sealants - PVC plastisols remain the dominant sealant coating to protect the underbody of cars, although some sprayable waterborne acrylic resins are also used. 

PVC plastisols are used in autobody undercoatings and gap sealants, using mainly precipitated calcium carbonate (PCC) to add slump resistance while maintaining ease of pressure injection. Stearate coated PCC with mean partiele size of 0.075 pm is the preferred product. It is used in underbody coatings at 25% by weight and at 50% in gap sealants. 

Automotive Sealants In filling underbody dead spaces, foamed plastisols compete with urethanes and other products. Such plastisols are highly filled, often with over 100 phr calcium carbonate, and plasticizer levels of 100-140 phr. Adhesion promoters for metal bonding (Chapter 12) are used with 2-4 phr of 5-7 p,m AZO, yielding expansion factors of 1.5-2. 

---