Table [17] lists the properties which affect appearance and gives in addition to the color range, the clarity, material, the burning rate, the effect of age and sunlight, the refractive index, and the machining quality of each synthetic resin.

Table [18] lists molding properties of synthetic resins. Of special interest are the possibilities of using a resin in injection molding. The thermoplastic resins and plastics (see softening point in table [20]) are generally preferred to the thermosetting materials for injection molding because they permit the reuse of material otherwise wasted.

Table [19] lists the strength properties of the synthetic resins; table [20] the heat properties; table [21] the electrical properties; and table [22] the resistance to acids, alkalies, and solvents. All of these qualities are important in some uses and each quality may be paramount in a few. Each material has its limitations and its special advantages and the consuming industry must choose the one best suited to its purposes. The tie-up between specific properties and particular uses is exemplified by vinyl resins, which because of their great elasticity at low temperatures, are used in safety glass, and by the polystyrene resins, which because of their electrical properties at high frequencies, are used in laminated electrical parts. As production of the various resins increases new uses will probably be found for most of them.

Table 19.—Synthetic resins and other plastics: Strength properties

TypeTensile strengthElongationModulus of elasticityCompressive strengthFlexural strengthImpact strength1 (foot pounds)Hardness2
Pounds per
square inch		PercentPounds per
square inch
× 10³		Pounds per
square inch		Pounds per
square inch		Brinell No
Synthetic resins:
Tar-acid—Formaldehyde:
Molded, wood flour filler6,000-11,00010-1516,000-36,0008,000-15,0000.10-0.28; I, N30-45
Molded, mineral filler5,000-10,00010-4518,000-36,0008,000-20,0000.11-0.36; I, N
Molded, fabric filler6,500-8,0007-1220,000-32,00010,000-13,0000.4-2.4; I, N
Laminated, paper base6,000-13,0005-2020,060-40,00013,000-20,0000.4-1.2; I, N24-40
Laminated, fabric base8,000-12,0005-1520,000-44,00013,000-20,0000.8-5.2; I, N30-45
Laminated, asbestos cloth base9,00018,000-40,00017,000
Cast5,000-12,0005-1515,000-30,0000.1-1.5; I, N30-45
Tar-acid—Furfural:
Wood flour filler5,000-12,00010-2528,000-36,00010,000-16,0000.08-0.52; C, N335-40
Mineral filler4,000-12,00010-4524,000-36,0008,000-14,0000.08-0.48; C, N344-46
Fabric filler5,000-10,0007-1226,000-30,00010,000-16,0001.6-3.1; C, N330-35
Urea—Formaldehyde8,000-13,0001624,000-35,00013,000-15,0000.7-1.5; C, U448-54
Vinyl, unfilled8,000-10,0003.5-4.110,000-13,0000.3-0.6; I, N15-25
Vinyl, filled6,000-12,0003.5-8.50.1-0.7; I, N15-25
Acrylate7,000-9,0001.068,00015,000-17,0000.25-0.5; C, N418-20
Polystyrene5,500-7,5001.04.6-5.113,000-13,5006,500-8,0000.16-0.25; I, N20-30
Other plastics:
Shellac compound900-2,000
Cold molded6,000-15,0005,300-7,5000.4; C
Nonrefractory}16,0006,0000.4; C
Refractory
Rubber compounds:
Chlorinated rubber3.0+; C, U
Modified isomerized rubber4,3000.0134.78,500-11,0007,000-9,0002.6-6.2; I, N585-90
Hard rubber4,000-10,0008-155.38,000-12,0000.5; I31
Casein7,6005.1-5.71.0; I23
Cellulose compounds:
Ethyl cellulose2,000-7,0002.81-4; I, N (per in. sq.)
Cellulose acetate sheet6,000-11,00020-551-34,000-16,0002-7; C, N (per in. sq.)66-11
Cellulose acetate molding3,500-10,00010-482-411,000-16,0005,200-8,8003-12; C, N (per in. sq.)66-7.5
Cellulose nitrate5,000-10,00010-402-43-12; C, N (per in. sq.)68-11

1 ASTM D256-34T. C = Charpy; I = izod; N = notched; U = unnotched.

2 2.5 mm ball; 25 kg. load unless otherwise noted.

3 50 kg. load.

4 10 mm. ball; 500 kg. load.