Grades of resin

An interest has been developed in the use of vanadium naphthenates as accelerators. In 1956 the author found that if MEKP was added to a polyester resin containing vanadium naphthenate the resin set almost immediately, that is, while the peroxide was still being stirred in. Whereas this effect was quite reproducible with the sample of naphthenate used, subsequent workers have not always obtained the same result. It would thus appear that the curing characteristics are very dependent on the particular grade of resin and of vanadium naphthenate used. It was also observed by the author that the gelation rate did not always increase with increased temperature or accelerator concentration and in some instances there was a retardation. Subsequent workers have found that whilst the behaviour of the naphthenate varies according to such factors as the resin and catalyst used, certain vanadium systems are of value where a high productivity in hand lay-up techniques is desired. 

If we investigate demineralization, for example, then from each OEM there are more than a dozen possible design configurations, with a further half-dozen or more grades of resin that can be potentially specified. Thus, it cannot be emphasized enough that higher purity water IX design projects must be undertaken by specialists. 

Spread in ratios reflects the influence of grade of resin and orientation of production (in or normal to machine direction). 

Properties often used by epoxy resin manufacturers to specify particular grades of resin include the epoxy content, viscosity or softening point, and color. In addition, properties such as density, vapor pressure, flash point, refractive index, solubility characteristics, and hydroxyl content are often reported. The important properties of uncured epoxy formulations with regard to most adhesive applications are... 

In some instances a much purer diglycidylhydantoin species has been isolated. Pure Resin Ila, 1,3-diglycidyl-5,5-dimethyl-hydantoin, was a readily crystallizable solid, m. 72-73 C ( ), epoxy content 8.25 eq/kg. The less pure sample described in Table I tended to supercool for a limited time, and could then be handled as a liquid. A distilled grade of Resin Ilb,... 

In long term exposure at high temperatures, there is the possibility of gradual oxidative embrittlement. Such applications should make use of a heat-stabilized grade of resin. 

A typical separation is shown in Figure 6.2 [10]. Acaroid resin is a component of a pyrotechnic composition, and was suspected to be the cause of a processing defect. Two grades of resin were compared by a number of analytical techniques. The resin is a natural product described as a resinotannic ester of cinnamic and p-coumaric acids . It is a polymeric material containing phenolic and aromatic residues. It is also said to contain up to 10% of benzoic, p-coumaric, and cinnamic acids. It was suggested that batch-to-batch variations might account for the differences in performance. 

Examination of the grades of resin showed virtually identical results, indicating that such a complex natural material was, in fact, very consistent in composition. In no case was any trace of the three free acids detected. 

A leading automobile manufacturer switched to the use of recycled poly(ethylene terephthalate) (PET)(from soda botdes) to fabricate components such as grille reinforcements, window frames, engine covers, and trunk carpets. The use of recycled grade of resin as opposed to virgin resin not only reduced the cost of production but also provided a significant (in 1999, 7.5 million pounds) annual market for recycled PET resin. 

The best known product made from aromatic polyester, however, is the blow-molded soda bottle, where the growth has been particularly dramatic during the past few years.This application accounts for 70-80% of the resin consumption and exploits the excellent barrier properties of the resin to carbon dioxide. It also requires the resin to be processed under conditions that would yield an amorphous (transparent) polymer with good gas barrier properties. The number-average molecular weight of the grade of resin used in bottles is about 80,000 (that used in fibers and films is about 45,000). 

To ensure the desired properties and for facile processing of the material, additives are mixed in with the resin during compounding. Some of these are inert fillers or recycled plastic used to bring down the cost of the manufactured product, while others are used to ensure specific functionalities. Table 4.8 indicates the ranges of levels at which these additives are typically used. The exact level depends on the grade of resin as well as on the properties demanded of the compound. The main classes of additives in plastics are shown in Figure 4.12 ... 

With more than 15,000 grades of resins to choose from in the United States alone, over 6000 grades in Europe, and nearly 10,000 grades in Japan, it is not difficult to appreciate the magnitude of this problem. It is further compounded by the fact that the data for many of the products often lacks sufficient information regarding test conditions, specimen details, etc., in commercial databases or even resin manufacturers product literature. 

Figure 93 Variation of wdght-aveiage molecular weig of LDPE versus melt flow index for autoclave and tubular grades of resin (O) A series ( ) B series, (A) C series, and ( ) T series. (From Ref. 3.)...

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