FIELD: process engineering.
SUBSTANCE: invention relates to preform for production of plastic containers by two-step blowing and stretching. This preform ahs elongated case with one lengthwise end closed by bottom and opposite end abutting on lengthwise filler neck section provided with threaded segments or similar positive ledges. Said preform is made of plastic suitable for blowing and stretching. Said plastic features refractive index of 1.3-1.6 at 100°C to 120°C. Preform bottom is configured so that its outer wall and inner wall make a flat diverging lens. Preform bottom outer and inner wall that make diverging lens feature radii of curvature (c, b) that is 1.4 times larger than those of curvature (s, r) of connected outer or inner wall in preform case area.
EFFECT: higher accuracy of forming.
18 cl, 2 dwg
