General Purpose Resin

Structures present in cured polyester resin. Cross-linking via an addition copolymerisation reaction. The value of n 2-3 on average in general purpose resins... 

Most conventional general purpose resins employ either maleic acid (usually as the anhydride) or its fra/jj-isomer fumaric acid (which does not form an anhydride) as the unsaturated acid (Figure 25.3). 

Because of its low price, compatibility, low viscosity and ease of use styrene is the preferred reactive diluent in general purpose resins. Methyl methacrylate is sometimes used, but as it does not copolymerise alone with most unsaturated polyesters, usually in conjunction with styrene in resins for translucent sheeting. Vinyl toluene and diallyl phthalate are also occasionally employed. The use of many other monomers is described in the literature. 

A number of photopolymer printing plates are already known. Their basic structures are to combine one of the general purpose resins such as cellulose (1), polyamide (2J, polyester, poly urethane (3j, polyvinyl alcohol (4), synthetic rubber (5) and the like with photopolymerizing vinyl monomer, photopolymerization initiator and so on. Any one of the plates of such structures can be used as a press plate, but they can not be used as an original plate for duplicate plate owing to their insufficient hardness, toughness and the similar negative properties. 

Commercial polystyrene, one of the most representative general-purpose resins, is an amorphous atactic polymer with no melting point (softening temperature ca 100 °C, glass transition temperature ca 70-100 °C). Since the discovery of Ziegler-Natta catalysts, many efforts to produce stereoregular polystyrenes have been made. 

General Purpose Resins. Homopolymer and copolymer resins produced by suspension, emulsion, bulk, or solution techniques are included... 

In 1960, the American Society for Testing and Materials (ASTM) completed work on tests and standardizations and issued D1755, "Specification for Poly(Vinyl Chloride) Resins. In this specification, type GP refers to general purpose resins, and type D refers to dispersion resins (which will be discussed later). A similar specification for copolymer resins has been issued as ASTM D2427-78. 

Polyesters of this class vary from heavy, sticky gums to brittle but tacky solids. For this reason they are seldom handled in this form but are immediately diluted with the monomer of choice. The resins are available in a wide range of viscosities. Most of the marketed resins yield rigid materials when cured. Flexible resins are available but are used for blending with rigid ones to impart flexibility. The properties of a typical general-purpose resin for matched die-molding work are lisied in Table 15-9. 

FIGURE 4.12 Curing of unsaturated polyesters, (a) Species in polyester resin ready for laminating, (b) Structures present in cured polyester resin. Cross-linking takes place via an addition copolymerization reaction. The value of n 2-3 on average in general-purpose resins. (After Brydson, J. A. 1982. Plastics Materials. Butterworth Scientific, London, UK.)... 

General purpose polyesters are based on phthalic anhydride as the saturated monomer and are the lowest-cost class of resin. These general purpose resins are not normally recommended for use in corrosive service. They are adequate for use with nonoxidizing mineral acids and corrodents that are relatively mild. Tests have indicated that general purpose resins will provide satisfactory service with the following materials up to 125°F (52°C) ... 

General purpose resins are not satisfactory in contact with the following Oxidizing acids. 

This is a premium corrosion-resistant grade resin. It costs approximately twice as much as a general purpose resin and approximately one-third more than an isophthalic resin. The structural formula is shown in Figure 3.3. 

Can, Z.Y. ed., Handbook of General-Purpose Resins, Chinese Petrochemicals Publisher, Beijing, China, 1999. 

Chem. Descrip. Phenolic modified alkyd (TOFAoil type) in xylene Uses Alkyd for metal/wood primers, automotive/industrial primers, aerosol finishes, aluminum paints, machine enamels, flooring finishes, marine finishes, lawnmower/toy enamels Features General purpose resin fast drying and nonlifting Properties Gardner 12 max. color dens. 8.3 Ib/gal vise. W-Y acid no. 35 50% NV... 

Uses Polyamide for inks, coatings, adhesives Features General purpose resin exc. adhesion, water resist., gloss, high vise. neutral termination... 

An experiment sample is the polypropylene which is one of the four major general- purpose resin. It shows the different polypropylene (PP) of three kinds of proporties in Table 1. A polypropylene film as prep>ared (PPl) and the polypropylene drawn film (PP2) to two axes (Futamura Chemicals) were used as base polymers. The porous film containing pores of several micro meters in radius prep>ared (PP3) was drawn to the thickness of 75pun. 

For weatherability it has been reported that after outdoor exposure of ASA resin, there is extremely little deterioration of the mechanical properties such as impact and elongation, and there is substantially no change in appearance. ASA resin can endure the conditions of outdoor use for a long time in comparison to the general-purpose resin. 

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