1 Specified refractive degree.
Note.—The values for the properties in this table are based upon maximum and minimum figures submitted to Modern Plastics by a number of manufacturers of each type of material. Differences in test procedures and sizes of test specimens may lead to erroneous conclusions in some cases if direct comparisons are attempted. Special grades of materials are often available which excel in one particular property.
Source: Modern Plastics, vol. 15, no. 2, opp. p. 120. October 1937.
Table 18.—Synthetic resins and other plastics: Molding properties
| Type. | General molding qualities | Compression molding temperature | Compression molding pressure | Injection molding temperature | Injection molding pressure | Compression ratio | Mold shrinkage | Effect on metal inserts |
|---|---|---|---|---|---|---|---|---|
| °F. | Pounds per square inch | °F. | Pounds per square inch | Inches per inch | ||||
| Synthetic resins: | ||||||||
| Tar-acid—Formaldehyde: | ||||||||
| Molded, wood flour filler | Excellent | 280-360 | 1,600-4,500 | 275-375 | 2,000-10,000 | 2.5-3.0 | 0.006-0.010 | Inert. |
| Molded, mineral filler | Excellent to fair | 270-350 | 1,600-6,000 | 275-350 | 2,000-15,000 | 2.2-7.1 | .002-.006 | Do. |
| Molded, fabric filler | Good to fair | 270-330 | 3,000-8,000 | 2.5-11.0 | .003-.007 | Do. | ||
| Laminated, paper base | 250-365 | 1,000-3,000 | 1.5-3.0 | Do. | ||||
| Laminated, fabric base | 250-365 | 1,000-3,000 | 1.5-3.0 | Do. | ||||
| Laminated, asbestos cloth base | 250-325 | 1,000-3,000 | Do. | |||||
| Cast | Do. | |||||||
| Tar-acid—Furfural: | ||||||||
| Wood flour filler | Excellent | 330-400 | 1,000-3,000 | 250-290 | 300-5,000 | 2.5-3.0 | .005-.009 | Do. |
| Mineral filler | do | 330-360 | 1,000-3,000 | 250-290 | 300-5,000 | 2.5-6.0 | .002-.006 | Do. |
| Fabric filler | Good to fair | 300-360 | 1,000-3,000 | 250-290 | 300-50,000 | 4.0-15.0 | .0025-.006 | Do. |
| Urea—Formaldehyde (alpha cellulose filler) | Excellent | 290-325 | 1,500-6,000 | 3.0 | .007-.011 | Do. | ||
| Vinyl, unfilled | Good | 240-275 | 1,500-2,000 | 2.0 | .001 | Not used. | ||
| Vinyl, filled | Excellent | 250-300 | 2,000-2,500 | 1.5-3.5 | .000 | Inert. | ||
| Acrylate | do | 285-315 | 1,500-5,000 | 325-475 | 3,000-30,000 | 2.0 | .002-.003 | |
| Polystyrene | Good | 280-325 | 300-2,000 | 300-375 | 3,000-30,000 | 2.5 | .002-.0025 | |
| Other plastics: | ||||||||
| Shellac compound | do | 240 | 1,000-1,200 | .002 | Do. | |||
| Cold molded: | ||||||||
| Nonrefractory | Fair | 4,000-12,000 | 2.5 | .000-.022 | Do. | |||
| Refractory | do | 4,000-12,000 | 3.5 | .000 | Do. | |||
| Rubber compounds: | ||||||||
| Chlorinated rubber | do | 200-225 | 2,000-5,000 | 2.0-3.0 | ||||
| Modified isomerized rubber | Good | 260-300 | 1,200-4,000 | 3.0 | .000 | Do. | ||
| Hard rubber | Fair | 285-350 | 1,200-1,800 | 180-220 | 2,000-5,000 | 4.0-6.0 | ||
| Casein | Poor | 200-225 | 2,000-2,500 | |||||
| Cellulose compounds: | ||||||||
| Ethyl cellulose | Excellent | 212-300 | 1,000-5,000 | 2.2-2.9 | .0003-.0007 | Do. | ||
| Cellulose acetate sheet | do | 210-320 | 500-5,000 | (1) | Do. | |||
| Cellulose acetate molding | do | 250-350 | 500-5,000 | 300-440 | 3,000-30,000 | 2.0-2.8 | (1) | Do. |
| Cellulose nitrate | Good | 185-250 | 2,000-5,000 |
1 Positive and injection 0.002-0.003; semipositive 0.005-0.007; flash 0.008-0.009.
Note.—The values for the properties in this table are based upon maximum and minimum figures submitted to Modern Plastics by a number of manufacturers of each type of material. Differences in test procedures and sizes of test specimens may lead to erroneous conclusions in some cases if direct comparisons are attempted. Special grades of materials are often available which excel in one particular property.
Source: Modern Plastics, vol. 15, No. 2, opp. p. 120. October 1937.