Plastics foil for the manufacture of audio-visual information carriers
AssigneeHoechst Aktiengesellschaft
InventorsHans-Joachim Andrascheck, Rainer Mucke, Werner Lorz, Heinz Borchard, Jurgen Buck, Herbert Knothe, Bruno Rybka
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Abstract
A rigid polyvinyl chloride foil with modified impact resistance and free from plasticizer especially suitable for the manufacture of audio-visual information carriers with stamped spiral grooves from which the information is played back by pressure scanning. The foil is characterized by a special combination of properties such as flow, reduction in length, toughness, surface resistance, elasticity, peak-to-valley height and surface deposit.
Claims3
Rigid polyvinyl chloride foil free from plasticizer and having modified impact resistance, suitable for the manufacture of audio-visual information carriers with stamped in spiral grooves carrying the information reproducible by pressure scanning characterized by the following properties:
- a. a flow corresponding to a melt viscosity in the range of from 20 to 72 g/10 minutes,
- b. a reduction in length of at most 20 % at 160.degree. C,
- c. a toughness corresponding to a factor of at least (25% . mm.sup.2)/newtons in longitudinal and transverse directions
- d. a surface resistance of at most 10.sup.10 ohms,
- e. an elasticity corresponding to an elastic modulus in the range of from 2,500 to 5,000 newtons/mm.sup.2,
- f. a peak-to-valley height corresponding to a Perth-O-Meter value of less than 0.4 .mu.m, and
- g. a surface deposit corresponding to a foil extraction residue of less than 0.012% by weight.
Dependencies are inferred from the claim text.