METHOD FOR PRODUCING POWDER LEADS AND PRODUCTS PRODUCED THEREWITH

Abstract

A method for producing a powder lead is disclosed, wherein at least one colourant, at least one filler and at least one binder are mixed with a carrier liquid, leads are shaped from the wet compound, the leads shaped in step b) are guided through a chamber in which they are exposed to a pulverulent covering agent, and the powdered leads are guided into a drying apparatus and dried therein.

Claims

1. A method for producing a powder lead, comprising: a. mixing at least one colourant, at least one filler, and at least one binder with a carrier liquid to form a wet compound, b. shaping leads from the wet compound to form shaped leads, c. guiding the shaped leads through a chamber, d. exposing the shaped leads to a pulverulent covering agent in the chamber to form powdered leads, e. guiding the powdered leads into a drier, and f. drying the powdered leads in the drier.

2. The method according to claim 1, wherein the at least one colourant comprises at least one pigment present in powder form.

3. The method according to claim 1, wherein the pulverulent covering agent is a wax, a polymer, or a wax and a polymer, and wherein the pulverulent covering agent melts at a temperature of from 50 C. to 120 C.

4. The method according to claim 1, wherein the shaped leads are exposed to the pulverulent covering agent in a proportion of from 0.5% to 10% by weight, based on the weight of the shaped leads.

5. The method according to claim 1, wherein the shaping leads comprises shaping the leads in an extrusion apparatus.

6. The method according to claim 1, wherein, during the exposing of the shaped leads, the shaped leads are powdered with the pulverulent covering agent using a corona gun.

7. The method according to claim 1, wherein the drying of the powdered leads comprises drying at a temperature of from 50 C. to 120 C. over a period of from 8 hours to 24 hours.

8. The method according to claim 1, further comprising covering the powdered leads with a shrink sleeve.

9. A powder lead obtained according to the method of claim 1.

10. A stabilized powder lead, consisting of: a lead core containing at least one colourant, at least one filler, and at least one binder; and a sheath composed of a stabilizing covering agent consisting of a wax, a waxy substance, or a polymer, the stabilizing covering agent melts at a temperature between 50 C. and 120 C., and wherein the stabilizing covering-agent proportion of the finished lead is less than 10% by weight and the depth of penetration of the covering agent into the lead core is less than 0.05 m.

11. The stabilized powder lead according to claim 10, wherein the sheath has a thickness within the range of from 0.05 mm to 0.2 mm, or the depth of penetration of the covering agent into the core is not more than 0.05 m for 95% of the covering agent, or the sheath has a thickness within the range of from 0.05 mm to 0.2 mm and the depth of penetration of the covering agent into the core is not more than 0.05 m for 95% of the covering agent.

12. The stabilized powder lead according to claim 10, wherein the stabilized powder lead is covered with a shrink sleeve.

13. The stabilized powder lead according to claim 10, wherein the stabilized powder lead is a cantilevered lead.

14. A use of the stabilized powder lead according to claim 10 for the production of a cosmetic pencil.

15. The use according to claim 14, wherein the stabilized powder lead is inserted into a rotary device as cantilevered lead or is inserted into a blank as pencil lead.

16. The stabilized power lead of claim 10, wherein the depth of penetration of the covering agent into the lead core is less than 0.02 m.

Description

EXAMPLE 1

[0058] A compound for a powder lead was produced. To this end, a dry phase composed of silica, kaolin, mica and/or mica-like constituents and polymethyl methacrylate, pigments and pearls with a binder phase containing magnesium aluminium silicate, align, and sorbitan laurate and preservatives was kneaded with water to form a moist compound. Said moist compound was guided into an extrusion apparatus and, by means of pressure through the cylinder, leads were pressed out of the apparatus.

Core length: 627 mm
Cutting interval: 2 s per 627 mm, or 313.5 mm/s

[0059] The leads pressed out of the extrusion apparatus were then conducted into a chamber in which there was permanent circulation of fine-particulate hydrogenated castor oil having a melting range of 85-88 C. as covering agent, with the result that the lead was uniformly covered by this powder. The layer thickness of the cover substance was set by means of the amount of covering agent in the chamber and the circulation rate as well as the rate of movement of the leads. Coating was achieved by using a corona gun, as is also used for the application of automotive paint. Charge strength and flow-through speed were set such that the desired layer thickness was achieved.

[0060] After leaving the chamber, the powdered leads were dried to constant weight in a drying oven at a temperature of 90 C. for at least 8 hours.

[0061] The dried leads were then cut to the desired length and subsequently provided with a shrink sleeve.

[0062] In the case of leads which were produced in a comparative test with the same composition and the same method, but without addition of the covering agent, it was not possible to overlay a shrink sleeve, since the leads crumbled. In addition, there were problems with cutting to length.

[0063] The finished leads were then inserted into shell blanks made of wood and glued. After decoration and sharpening, finished pencils were obtained which could be applied very easily to the skin and provided a strongly coloured application, with the application being experienced as highly pleasant.

EXAMPLE 2

[0064] Lead compounds were produced from the ingredients listed in Table 1 below.

TABLE-US-00001 TABLE 1 NAME OF RAW MATERIAL [INCI] PARTS BY WEIGHT Pigments 71.650 Water 30.001 Filler, e.g. synthetic fluorphlogopite, kaolin 20.410 Moisturizer, e.g. pentylene glycol 17.970 Silica 10.480 Optical modifier, e.g. polymethyl methacrylate beads 10.470 Plasticizer, e.g. caprylyl glycol; dipropylene glycol; 1.899 glyceryl caprylate Preservative, e.g. dehydroacetic acid 0.800 Emulsifier, e.g. sorbitan laurate 0.610 Thickener, e.g. Mg Al silicate, algin 0.500 pH modifier, e.g. citric acid 0.420 Flavourings, e.g. triethyl citrate 0.407 TOTAL AMOUNT 165.617

[0065] Leads having a diameter within the range from 3.77 mm to 4.08 mm were extruded from the lead compound, with the upstream pressure being within a range from 55 to 65 bar. The speed of the extruded lead strand was about 310 mm s.sup.1. The covering agent was electrostatically charged with a voltage of 45 kV and at a current of 4.5 A. The electrostatically charged covering agent adhered upon contact with the lead strand. Non-adherent covering agent was sucked off in the chamber. After leaving the chamber, the covered lead strand was cut to length, yielding lead pieces having a length of 627 mm each. The lead pieces were placed onto a metal sheet and dried in a drying cabinet at 90 C. for 16 hours. After drying, the leads had a diameter within the range from 3.85 to 3.95 mm.

[0066] As described in Example 1, the leads were inserted into shell blanks and glued. Using the pencils obtained, a line was drawn on skin on a test person. The application was experienced as highly pleasant. The line was strongly coloured.