Double-layer mold for machine for producing lipsticks and like, and associated manufacturing process

Abstract

A mould (1) for a machine for producing lipsticks or similar stick-like cosmetic products is formed from two coaxial layers (5, 6) made of different chemically bonded silicone resins, in which the inner layer (5) of the smaller thickness is made of hard silicone resin, and the inner layer (6) of the smaller thickness is made of hard silicone resin. And the outer layer (6) with larger thickness is made of soft silicon resin.

Description

Technical Field

[0001] The present invention relates to a double-layer mould and a related manufacturing process for a machine that can be used for producing lipstick or similar stick-shaped cosmetics. Background Art

[0002] As is known, the manufacture of lipstick or similar cosmetics requires the use of a machine having cavities made of a thermally rigid and mechanically resistant material, each of which is lined internally with a hollow ogive-shaped mold made of a pliable plastic material, wherein the shape of the internal cavity is complementary to the desired shape of the outer surface of the lipstick. An appropriate amount of cosmetic composition is introduced into the interior of the cavity so as to form a lipstick (or similar cosmetic) of the desired shape, and the lipstick is removed from the mold after cooling the lipstick.

[0003] Arched moulds for the above-mentioned purpose are known, which are made of silicone, which has the dual requirement of being hard enough to withstand the mechanical stresses to which the mould is subjected during the production of the cosmetic product; and at the same time being flexible enough to allow the mould to be expanded or opened laterally by means of the creation of a vacuum in order to remove the cosmetic product from the mould.

[0004] Unfortunately, the standard silicones currently used to make such molds are susceptible to mechanical wear, even after several filling cycles (also depending on the ingredients included in the formulation of the chemical filling composition), and this forces lipstick manufacturers to frequently replace molds to allow compliant production and minimize production waste. Summary of the invention

[0005] The purpose of the present invention is to manufacture a mold of silicone material that can fully meet the above two requirements.

[0006] According to the invention, this object is achieved with the aid of a mould, characterised in that it is formed by two coaxial layers made of different chemically bonded silicones, wherein an inner layer of smaller thickness is made of hard silicone and an outer layer of greater thickness is made of soft silicone.

[0007] Compared to conventional single-layer moulds, the inner layer of the mould according to the invention increases the resistance of the mould to mechanical wear, improves heat exchange and resistance to chemicals present in the lipstick formula and also makes the lipstick surface glossier, while the outer layer makes it possible to open the mould with the aid of conventional forming vacuum of existing machines.

[0008] In order to manufacture a double-layer mold according to the present invention, the following method is advantageously envisaged, which method includes: introducing a male element into the interior of a first cavity to form a first space, which has a shape and size corresponding to the shape and size of the inner layer of the mold being manufactured; introducing a first fluid silicone material into the interior of the first space to form a mold inner layer; cooling the mold inner layer until the mold inner layer adheres to the male element; removing the male element with the adhered mold inner layer from the first cavity; introducing the male element with the adhered mold inner layer into the interior of a second cavity larger in size than the first cavity to form a second space, which has a shape and size corresponding to the shape and size of the outer layer of the mold being manufactured; introducing a second fluid silicone material into the interior of the second space to form a mold outer layer, which is chemically bonded to the mold inner layer to form a double-layer mold; cooling the double-layer mold; removing the male element from the double-layer mold while keeping the double-layer mold inside the second cavity; and removing the double-layer mold from the second cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The characteristics of the double-layer mould according to the invention and of the associated manufacturing process will become more apparent from the following detailed description of an embodiment of the invention shown by way of non-limiting example in the accompanying drawings, in which:

[0010] Figure 1 A two-layer mold is shown in perspective view;

[0011] Figure 2 The same mould is shown in a top plan view;

[0012] Figure 3 In accordance with Figure 2 An axial cross-sectional view of the line III-III shows the mold;

[0013] Figures 4 to 7 The sequence of manufacturing steps for a two-layer mold is shown. DETAILED DESCRIPTION

[0014] Figures 1 to 3 , a double-layer pointed arch mold is shown by way of example, wherein the double-layer pointed arch mold is indicated as a whole by the number 1, and the double-layer pointed arch mold has a hollow body 2 with a substantially truncated cone outer shape, and the hollow body 2 has an inner cavity 3, which is open at the upper part and closed at the lower part, and the shape of the inner cavity 3 corresponds to the outer shape of the lipstick or other cosmetics to be produced by the mold 1. The body 2 ends with a flat flange 4 at the upper part.

[0015] like Figure 3As clearly highlighted in FIG. 1 , the mold 1 is formed by a thin inner layer 5 of relatively small thickness and an outer layer 6 of relatively large thickness, which are chemically bonded to each other. The thickness of the inner layer 5 may be, for example, 1 mm, while 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 ShA20 / 25), while the outer layer 6 is made of a soft silicone material (preferably with a hardness of ShA10 / 12).

[0016] Advantageously, the manufacturing process of the mold 1 with the inner layer 5 and the outer layer 6 follows Figures 4 to 7 The pattern shown in .

[0017] Specifically, the male element 7 is introduced into the interior of the cavity 8 of the mold 9 to define a space having the same shape and size as that required for the inner layer 5 of the mold 1. A first suitable fluid silicone material is introduced into the interior of the space, and then the first suitable fluid silicone material is cooled to form a thin, hard and rigid pointed arched layer 5 ( Figure 4 ).

[0018] The male component 7 with the adhered layer 5 is then removed from the mold 8 ( Figure 5 ), and then the male element 7 is introduced together with the layer 5 into the interior of the wider cavity 10 of the rigid mold 11 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. A second suitable fluid silicone material is introduced into the second space and then cooled to form a thick and soft pointed arch layer 6, which is chemically bonded to the layer 5 adhered to the male element 7 ( Figure 6 ).

[0019] The male element 7 is then removed from the rigid mould 11, while the two layers 5 and 6 are retained by means of a pneumatic vacuum being formed outside the cavity 10 (a technique known per se in the field of this machine). Figure 7 ). After the vacuum is removed, the pointed arch mold 1 with two coaxial layers 5 and 6 forming a single body can finally be removed from the mold 11, for example Figures 1 to 3 Pointed arch mold 1.

Claims

1. A mould (1) for a machine for producing lipstick or similar stick-shaped cosmetics, characterized in that the mould (1) is formed by two coaxial layers (5, 6) made of different chemically linked silicone resins, wherein: The thinner inner layer (5) is made of hard silicone and the thicker outer layer (6) is made of soft silicone.

2. A method for manufacturing a mold (1) having two coaxial layers (5, 6) according to claim 1, the method comprising in sequence: The method comprises introducing a male component (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 being manufactured; introducing a first fluid silicone material into the first space to form the inner layer of the mold; cooling the inner layer of the mold (5) until it adheres to the male component (7); removing the male component (7) with the adhered inner layer of the mold (5) from the first cavity (8); introducing the male component (7) with the adhered inner layer of the mold (5) into a second cavity (10) having a size larger than the first cavity (8) to form a second space, the second space The invention relates to a method for manufacturing a mold having a shape and size corresponding to that of an outer layer of the mold being manufactured in the second cavity (10); introducing a second fluid silicone material into the second space to form an outer mold layer (6), the outer mold layer (6) being chemically bonded to the inner mold layer (5) to form a mold (1) having two layers (5, 6); cooling the mold (1) having two layers; removing the male element (7) from the mold (1) having two layers while keeping the mold (1) inside the second cavity (10); and removing the mold (1) having two layers (5, 6) from the second cavity (10).

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