Container preform made of plastics material

A method for manufacturing a container by blow molding or stretch-blow molding, comprising at least the following steps:

• providing a preform;
• heating the body of the preform by exposure to monochromatic or quasi-monochromatic infrared radiation of predetermined intensity to form a preheated preform;
• and
• forming the container by injecting a pressurized fluid into the preheated preform,
• wherein the preform comprises:
• a body that is rotationally symmetrical about a vertical central axis, the body having an outer wall and an inner wall, a radial distance between the outer wall and the inner wall defining a wall thickness;
• an open neck that extends as a continuation of the body from an upper end thereof, the neck being separated from the body by an annular collar;
• and
• a base that closes the body from a lower end thereof, the base being rotationally symmetrical about the central axis;
• wherein the body has a substantially cylindrical shape in which the wall thickness increases from the collar towards the base over a cone height Hc, the cone height Hc being a mean of a cone height Hc1 of the outer wall of the body and a cone height Hc2 of the inner wall of the body,
• the body comprising a first wall thickness E2 under the collar at an under-neck reference height Hr, a second wall thickness E of at the cone height Hc, and a third wall thickness E1 at the lower end of the body, such that the third wall thickness E1 is between 0.7 E and 1.2 E and such that the first wall thickness E2 is between 0.5 E and 1.0 E, wherein the second wall thickness E corresponds to the greatest thickness of the wall of the body at the cone height Hc1 or Hc2.

A mold for forming a preform, the mold comprising at least:

• a mold body having a lateral wall with an impression of an outer face of a body of the preform and a mold base with an impression of an outer face of the base of the preform and a core with an impression of an inner face of the preform,
• wherein the preform comprises:
• the body, the body being rotationally symmetrical about a vertical central axis, the body having an outer wall and an inner wall, a radial distance between the outer wall and the inner wall defining a wall thickness;
• an open neck that extends as a continuation of the body from an upper end thereof, the neck being separated from the body by an annular collar;
• and
• the base, wherein the base closes the body from a lower end thereof, the base being rotationally symmetrical about the central axis;
• wherein the body has a substantially cylindrical shape in which the wall thickness increases from the collar towards the base over a cone height Hc, the cone height Hc being a mean of a cone height Hc1 of the outer wall of the body and a cone height Hc2 of the inner wall of the body,
• the body comprising a first wall thickness E2 under the collar at an under-neck reference height Hr, a second wall thickness E of at the cone height Hc, and a third wall thickness E1 at the lower end of the body, such that the third wall thickness E1 is between 0.7 E and 1.2 E and such that the first wall thickness E2 is between 0.5 E and 1.0 E, wherein the second wall thickness E corresponds to the greatest thickness of the wall of the body at the cone height Hc1 or Hc2.