Abstract: Preform, made of plastic material for the manufacturing of hollow bodies through a blow-molding process, in which said preform comprises a substantially cylindrical body (1) having an open end (2) and a closed end {4), in which said closed end (4) has an outer surface with a varying curvature which is entirely enveloped within a hemispherical surface having a radius equal to the outer radius (R) of the cylindrical body (1) of the preform, said outer surface with varying curvature being tangent to the hemispherical surface in which it is enveloped in correspondence of the circular crown C and of the preform vertex.

Abstract: A preform (1) of plastic material for manufacturing bottles through a blow-moulding process includes a substantially cylindrical central body (3) having an open end (2) and a closed end (4). In correspondence of the central area of the closed end (4) there is provided a hollow appendix (5), projecting outwards of the preform, capable of internally housing the tip end of a stretching rod of the preform (1). Both the hollow appendix (5) and the remaining side portion of the closed end (4) of the preform may be spherical, conical, elliptical or parabolic.

Abstract: A preform (1) of plastic material for manufacturing bottles through a blow-moulding process includes a substantially cylindrical central body (3) having an open end (2) and a closed end (4). In correspondence of the central area of the closed end (4) there is provided a hollow appendix (5), projecting outwards of the preform, capable of internally housing the tip end of a stretching rod of the preform (1). Both the hollow appendix (5) and the remaining side portion of the closed end (4) of the preform may be spherical, conical, elliptical or parabolic.