Two-layer mold for machines for manufacturing lipsticks and the like and related manufacturing methods

Abstract

The mold (1) for a machine for manufacturing lipstick or similar stick cosmetics is formed of two coaxial layers (5, 6) of different types of silicone chemically bonded, the inner layer (5) of which consists of a hard silicone with a small thickness and the outer layer (6) consists of a soft silicone with a large thickness.

Description

Technical Field

[0001] The present invention relates to a two-layer mold and related manufacturing methods that can be used in machines for manufacturing rod-shaped cosmetics such as lipsticks.

Background Art

[0002] As is well known, in the manufacture of lipsticks or similar cosmetics, machines having cavities made of materials with thermal rigidity and mechanical resistance are used, and each cavity is covered inside by a hollow mold with an ogive shape. The mold is made of a malleable plastic material and has an internal cavity with a shape complementary to the desired shape of the outer surface of the lipstick. When an appropriate amount of cosmetic composition is introduced into the cavity, a lipstick (or similar cosmetic) of the desired shape is formed and removed from the mold after cooling.

[0003] Ogive-shaped molds are known for the aforementioned applications and are made of silicone that requires both sufficient rigidity to withstand the mechanical stresses the mold undergoes during the manufacture of cosmetics and sufficient flexibility to allow the mold to expand or open laterally by the generation of a vacuum for removing the cosmetics.

[0004] Unfortunately, the standard silicone currently used in the manufacture of such molds undergoes mechanical wear even after several filling cycles (depending also on the components included in the formulation of the chemical filling composition). Therefore, lipstick manufacturers need to frequently replace the molds to enable production in compliance with regulations and minimize production waste.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to produce a mold of a silicone material that can fully meet the above two requirements.

Means for Solving the Problems

[0006] According to the present invention, such an object is achieved by a mold characterized in that it is formed by two coaxial layers of chemically bonded different types of silicone, the inner layer thereof being a hard silicone with a smaller thickness and the outer layer being a soft silicone with a larger thickness.

[0007] Compared with the conventional single-layer mold, the inner layer of the mold according to the present invention enhances the resistance to mechanical wear of the mold, improves the resistance to heat exchange and chemicals present in the lipstick formulation, and also gives a stronger gloss to the surface of the lipstick, while the outer layer enables the mold to be opened by the conventional vacuum generation by the existing machine.

[0008] In order to manufacture the two-layer mold according to the present invention, advantageously, a male element is introduced into the first cavity to form a first space having a shape and size corresponding to the shape and size of the inner layer of the mold to be manufactured, a first fluid silicone material is introduced into the first space to form the mold inner layer, the mold inner layer is cooled until it adheres to the male element, the male element with the adhered mold inner layer is taken out of the first cavity, the male element with the adhered mold inner layer is introduced into a second cavity having a size larger than that of the first cavity so as to form a second space having a shape and size corresponding to the shape and size of the outer layer of the mold to be manufactured, a second fluid silicone material is introduced into the second space to form a mold outer layer chemically bonded to the inner layer of the mold so as to form a two-layer mold, the two-layer mold is cooled, the male element is taken out of the two-layer mold while holding the two-layer mold in the second cavity, and the two-layer mold is taken out of the second cavity. A manufacturing method including the above is envisioned.

[0009] The features and related manufacturing method of the two-layer mold according to the present invention will become more apparent from the following detailed description of the embodiments shown as non-limiting examples in the accompanying drawings.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0011] The ogive-shaped two-layer mold illustrated in Figures 1 to 3 is indicated as a whole by reference numeral 1, and has a hollow body 2 having a substantially frustoconical outer shape. The body 2 has an internal cavity 3 that is open at the top and closed at the bottom. The shape of the internal cavity 3 corresponds to the outer shape of a lipstick or other cosmetic for which the mold 1 is intended. The body 2 terminates at the top with a flat flange 4.

[0012] As clearly emphasized in FIG. 3, the mold 1 is formed by an inner layer 5 with a smaller thickness and an outer layer 6 with a larger thickness, which are chemically bonded to each other. The thickness of the inner layer 5 may be, for example, 1 mm, and the thickness of the outer layer 6 may be, for example, 2 mm. The inner layer 5 is made of a hard and rigid silicone material (preferably with a hardness of ShA 20 / 25), and the outer layer 6 is made of a soft silicone material (preferably with a hardness of ShA 10 / 12).

[0013] Advantageously, the manufacturing method of the mold 1 with the inner layer 5 and the outer layer 6 follows the embodiments shown in FIGS. 4 to 7.

[0014] In particular, the male element 7 is introduced into the cavity 8 of the mold 9 to define a space having the same shape and size as the desired shape and size of the inner layer 5 of the mold 1. By introducing a first suitable fluid silicone material into such a space and then cooling it, a thin, hard, and rigid layer 5 in the shape of an ogive that adheres to the male element 7 is formed (FIG. 4).

[0015] Next, the male element 7 with the adhering layer 5 is removed from the mold 8 (FIG. 5), and subsequently, it is introduced into a wider cavity 10 of a rigid mold 11 together with the layer 5 to define a second space having the same shape and size as the desired shape and size of the outer layer 6 of the mold 1. By introducing a second suitable fluid silicone material into such a second space and cooling it, a thick, soft layer 6 in the shape of an ogive that is chemically bonded to the layer 5 adhering to the male element 7 is formed (FIG. 6).

[0016] Next, the male element 7 is removed from the rigid mold 11, but within the mold 11, instead, two layers, namely the layer 5 and the layer 6, remain held by vacuum formation due to the air pressure outside the cavity 10 (this technique itself is well-known in the machinery of this field) (FIG. 7). By releasing the vacuum, finally, the ogive-shaped mold 1 having the integrated two-layer coaxial layers 5 and 6 as shown in FIGS. 1 to 3 can be taken out from the mold 11.

Description of Reference Numerals

[0017] 1 Mold 5 Inner layer 6 Outer layer 7 Male element 8 First cavity 10 Second cavity

Claims

1. A mold (1) for a machine for manufacturing lipstick or similar stick-shaped cosmetics, characterized in that it is formed by two coaxial layers (5, 6) of different types of chemically bonded silicone, the inner thin layer (5) being made of hard silicone and the outer thick layer (6) being made of soft silicone.

2. A method for manufacturing a mold (1) having the two coaxial layers (5, 6) according to Claim 1, comprising: introducing a male element (7) into a first cavity (8) to form a first space having a shape and size corresponding to the shape and size of the inner layer of the mold to be manufactured; introducing a first fluid silicone material into the first space to form a mold inner layer (5); cooling the mold inner layer (5) until it adheres to the male element (7); removing the male element (7) with the adhered mold inner layer (5) from the first cavity (8); introducing the male element (7) with the adhered mold inner layer (5) into a second cavity (10) having a size larger than that of the first cavity (8) to form a second space having a shape and size corresponding to the shape and size of the outer layer of the mold to be manufactured; introducing a second fluid silicone material into the second space to form a mold outer layer (6) chemically bonded to the mold inner layer (5) so as to constitute a mold (1) having two layers (5, 6); cooling the mold (1) having the two layers; removing the male element (7) from the mold (1) while holding the mold (1) having the two layers in the second space; sequentially removing the mold (1) having the two layers (5, 6) from the second cavity (10).

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