Stick of cosmetic product comprising two compositions having a surface in relief, method and device for manufacturing such a stick of cosmetic product
Stick of cosmetic product, in particular of lipstick, comprising two compositions A and B extending along a longitudinal axis, method and device for manufacturing such a stick of cosmetic product, the stick of cosmetic product, the stick of cosmetic product having a side surface presenting a decorative surface portion in relief.
1 . A method for manufacturing a stick of cosmetic product, in particular of lipstick, comprising two compositions A and B, extending along a longitudinal axis, the stick having a side surface presenting a decorative surface portion in relief, the method including:
a step of placing a core in an elastic cup having a surface portion in relief, the core coming into contact with the bottom of the cup,
a step of pouring or injecting a composition A between the core and the cup so as to form a first member,
a step of removing the core from the cup,
a step of pouring or injecting a composition B so as to form a second member, thereby forming a stick of cosmetic product, and
a step of deforming the cup so as to demold the stick of cosmetic product.
2 . The method according to claim 1 , enabling the manufacture of a stick of cosmetic product, in particular of lipstick, of the central part-sheath type, the two compositions A and B being arranged relative to one another to form a central part surrounded by a sheath along the longitudinal axis, the sheath having a side surface presenting the decorative surface portion in relief, the method including:
said sheath is formed during said step of pouring or injecting a composition A between the core and the cup,
said central part is formed during said step of pouring or injecting a composition B into the sheath.
3 . The method for manufacturing a stick of cosmetic product according to claim 1 , further comprising a step of lubricating the core.
4 . The method of claim 1 , using a device comprising:
a base having a cavity formed in the base,
said elastic cup received in the cavity, the cup having a surface in relief,
said core movable in translation between:
an inserted position in which the core is positioned in the cup, for pouring or injecting said composition A between the core and the cup so as to form a first member, the core coming into contact with the bottom of the cup,
and a withdrawn position in which the core is withdrawn from the cup for pouring or injecting said composition B so as to form a second member, thereby forming a stick of cosmetic product, and
a vacuum pump for deforming the cup so as to demold the stick of cosmetic product.
5 . The method of claim 4 , wherein the cup is of a size smaller than that of the cavity so as to define a space between the cup and the cavity, and wherein at said step of deforming the cup, said vacuum pump creates negative pressure in said space.
6 . The method of claim 4 , wherein the core has an air outlet channel leading between: the end of the core in contact with the inner surface of the cup, and a portion of the core outside the cup when the core is inserted into said cup.
7 . The method of claim 4 , wherein the device further comprises a pressure adjustment device which adjusts a pressure of the core in the cup when said core is inserted in said elastic cup.
8 . The method of claim 7 , wherein said pressure adjustment device comprises a spring.
9 . The method of claim 4 , wherein said device further comprises at least one ring guiding the core in translation and centering said core in the cup.
10 . The method according to claim 9 , wherein said at least one ring is retractable.
11 . The method according to claim 10 , wherein the device further comprises at least one magnet which maintains the at least one ring in a retracted position.
12 . The method according to claim 9 , wherein the core and the at least one ring are mounted on a block.
13 . The method according to claim 9 , wherein said at least one ring comprises a centering ring which engages with a housing provided in the base.
14 . The method according to claim 4 , wherein the device comprises a plurality of cavities, a plurality of elastic cups each having a surface in relief, and a plurality of cores, wherein the plurality of cavities are formed in the base, wherein each of the cups is received in each cavity, and wherein each of the cores is movable in translation between said inserted position in which the cores are positioned in the cups and said withdrawn position in which the cores are withdrawn from the cups.