Pen Having an Integrally Injection-Moulded Coating Sleeve
AssigneeA.W. Faber-Castell Cosmetics GmbH
InventorsWolfgang Kaul, Christina Zech
Life of this patent
Estimating the term…
Abstract
A pencil for applying a coloring and/or cosmetic substance, having a pigment core composed of the substance that is to be applied and a one-piece injection-molded casing encompassing the pigment core that is composed of a thermoplastic material that consists of a mix of a first plastic and a second plastic, wherein the casing, respectively viewed in the radial direction, has an outer enrichment zone with a higher concentration of the first plastic than in the middle region and the casing, respectively viewed in the radial direction, has an inner enrichment zone with a higher concentration of the first plastic than in the middle region.
Claims24
A pencil for applying a coloring and/or cosmetic substance, having a pigment core composed of the substance that is to be applied and a one-piece injection-molded casing encompassing the pigment core that is composed of a thermoplastic material that consists of a mix of a first plastic and a second plastic, characterized in that the casing, respectively viewed in the radial direction, has an outer enrichment zone with a higher concentration of the first plastic than in the middle region and the casing, respectively viewed in the radial direction, has an inner enrichment zone with a higher concentration of the first plastic than in the middle region.
The pencil according to one of the preceding claims, characterized in that over at least 80% or better still, at least 90% of its cross-section area, the plastic casing is composed of oth the first and the second plastics, with the two plastics being encountered in percentages by weight that differ by location.
The pencil according to the preceding claims, characterized in that the casing consists predominantly, at least up to 85%, or preferably exclusively, of the first and second plastics, plus any fillers and auxiliary materials such as pigments.
The pencil according to one of the preceding claims, characterized in that a plastic and preferably the first plastic comprises a weakly polar plastic with an electronegativity difference ΔEN in the range between 0.3 and 0.5, inclusive.
The pencil according to one of the preceding claims, characterized in that a plastic and preferably the second plastic is a strongly polar plastic with an electronegativity difference ΔEN in the range between greater than 0.5 and 1.7.
The pencil according to one of the preceding claims, characterized in that the first plastic is an AES or preferably a SAN.
The pencil according to one of the preceding claims, characterized in that the second plastic is a TPE or preferably a TPC-ET.
The pencil according to one of the preceding claims, characterized in that the material system comprising the casing is set up so that the first plastic has a weight proportion of at least 45% by weight or better still, at least 55%.
The pencil according to one of the preceding claims, characterized in that the upper limit for the first plastic in the injection-ready mix is 85% by weight or better still, 70% by weight.
The pencil according to one of the preceding claims, characterized in that at the outer circumference surface, the casing has a mathematically determined gloss level GU of more than 30 GU or better still, more than 40.
The pencil, preferably according to one of the preceding claims, characterized in that the casing has a structure composed of two layers that can be separated from each other and preferably, the one of these two layers that is closer to the surface is thinner.
The pencil according to one of the preceding claims, characterized in that the plastic casing consists of a non-foamed plastic.
The pencil according to one of the preceding claims, characterized in that the casing is embodied in the form of a tube that is open at both ends.
The pencil according to one of the preceding claims, characterized in that at one end, the casing tapers conically, preferably with a cone angle (Pi) of 25° to 35° relative to the longitudinal axis L of the casing.
The pencil according to one of the preceding claims, characterized in that at one end, the casing has a shoulder with a reduced diameter.
A method for producing a pencil with a casing according to one of the preceding claims, characterized in that
- a plasticized, injection-moldable compound is produced, composed of a first and second plastic material that are completely mixed with each other,
- the plastic materials are chosen so that they have solidification behaviors that differ from each other such that they separate when they come into contact with a cooled mold surface,
- the compound is injected at a high pressure of at least 900 bar or better still, at least 1100 bar, —preferably in an axial direction from one end of the subsequent casing—into a mold cavity of an injection mold forming the casing of the pencil,
- with the injection mold being intensively cooled such that directly against its wall surface that produces the mold cavity and over the entire length of the mold cavity, predominantly the first plastic material solidifies and is thus enriched against the wall surface,
- and then the two plastic materials in the region underneath this solidify together with less separation than in the region of the wall surface or without any separation.
The method according to one of the preceding claims, characterized in that the surface of the injection mold that forms the outer circumference surface has a roughness depth Rz≤5 μm.
The method according to one of the preceding claims, characterized in that the pigment core is cast in that the casing is inserted into a mold that seals the casing at its tapering end and that forms the subsequent shape of the unused tip of the pigment core and the compound that forms the pigment core is poured in at the other end of the casing.
Dependencies are inferred from the claim text.