Colored pencil lead, graphite lead, colored or graphite chalk

Abstract

Colored pencil lead, graphite lead, colored or graphite crayon for painting and / or drawing with a lead base containing waxes, at least one filler and at least one colorant, characterized in that the lead base further contains aluminium distearate and contains at least one functionalised metallocene polyolefin wax and at least one hardened wax.

Description

[0001] The invention relates to a colored pencil lead, graphite lead, colored or graphite chalk for painting and / or drawing with a lead base containing waxes, at least one filler, at least one colorant and aluminum distearate.

[0002] Waterproof leads or chalks are known from the state of the art, which are produced by extrusion processes from a lead base containing fats and / or waxes, fillers and color pigments and, if necessary, other additives.

[0003] EP 2 520 442 B1, for example, describes waterproof leads containing aluminum distearate, oxidized polyethylene wax, and fatty acid derivatives. While these leads are well suited for simple colored pencils, they are not easy to apply and exhibit poor coverage when applied to a painting surface.

[0004] EP 3 772 532 B1 discloses waterproof leads containing oxidized ethylene vinyl acetate wax (EVA) and at least one functionalized metallocene polyolefin wax. Although these colored pencil leads exhibit somewhat improved properties compared to the leads known from EP 2 520 442 B1 in terms of softness, they do not meet the expectations for very high-quality colored pencil leads, which are particularly desired for artists' pencils and other high-quality colored pencil leads.

[0005] It is therefore desirable to develop compositions for waterproof colored pencil leads, graphite leads, colored or graphite crayons that are softer to apply than state-of-the-art leads and that allow larger amounts of lead mass to be applied to the painting surface (paper, cardboard, or wood). Furthermore, better coverage should be possible when painting over different colors without compromising mechanical properties such as fracture strength compared to state-of-the-art leads.

[0006] It is therefore an object of the invention to provide colored pencil leads, graphite leads, colored or graphite crayons, in particular waterproof colored pencil leads, graphite leads, colored or graphite crayons, for painting and / or drawing, which have a soft application behavior and an opaque coating and can also be effectively produced by means of an extrusion process.

[0007] This object is achieved with a colored pencil lead, graphite lead, colored or graphite crayon, in particular a waterproof colored pencil lead, graphite lead, colored or graphite crayon, for painting and / or drawing, having the features according to claim 1. The colored pencil lead, graphite lead, colored or graphite crayon has a lead base containing waxes, at least one filler, and at least one colorant. According to the invention, the lead base further contains aluminum distearate, and the waxes comprise at least one functionalized metallocene polyolefin wax and at least one hardened wax, hardened oil, or hardened fat. Wax mixtures are thus also conceivable.

[0008] For the sake of simplicity, we will primarily refer to colored pencil leads or leads in the following.

[0009] Numerous tests led to the conclusion that a combination of aluminum disteart with functionalized metallocene polyolefin wax and hardened wax / hardened oil / hardened fat results in leads that are particularly soft to apply and also exhibit improved coverage compared to the described prior art. This was surprising, since a combination of components of the relatively hard and weakly applied leads from EP 2 520 042 B1 with components of an improved, but not sufficiently soft, manufacturable lead from EP 3 772 532 B1 resulted in a lead with significantly improved application properties compared to both of the patents cited in the prior art.

[0010] Hydrogenated waxes / oils / fats are waxes, oils, or fats that have undergone a "fat-hydrogenation" process. This involves hydrogenating oils or low-melting waxes and saturating existing double bonds. This increases the melting range of the "treated" wax / oil. Furthermore, hydrogenated waxes resinify significantly less than unhydrogenated waxes.

[0011] For the property profile of the mine, it has proven sufficient if the aluminum distearate is contained in the mine matrix in a proportion of 0.4 to 10.0 wt.%.

[0012] The functionalized metallocene polyolefin wax is preferably contained in the lead base mass in a proportion of 5.0 to 25.0 wt.%.

[0013] The at least one functionalized metallocene polyolefin wax preferably has a dropping point between 120 and 160 °C (ISO 2176) and an acid number between 16 and 50 mg KOH / g (ISO 2114).

[0014] In particular, the functionalized metallocene polyolefin wax used is ethylene-maleic anhydride copolymer (CAS No. 9006-26-2) or propylene-maleic anhydride copolymer (CAS No. 25722-45-6). Such functionalized metallocene polyolefin waxes are available, for example, under the trade names Licocene PP MA 6252 2) (Dropping point: 137 - 142°C; acid number: 38 - 45 mg KOH / g), Licocene PE MA 4221 2) (Dropping point: 120 - 126°C; acid number: 16 - 20 mg KOH / g) Licocene PE MA 4351 2) (Dropping point: 120 - 126°C; Acid number: 42 - 49 mg KOH / g) available.

[0015] The hardened wax or hardened wax mixture preferably has a dropping point between 50 and 120 °C (ISO 2176) and an acid number between 1 and 11 mg KOH / g (ISO 2114).

[0016] According to preferred embodiments, hydrogenated waxes or hydrogenated oils or hydrogenated fats from palm wax, rapeseed wax, sunflower wax, soy wax, ester wax, synthetic beeswax, mantan wax, paraffin wax, natural waxes, carnauba wax, and / or hydrogenated castor oil are mentioned, as well as hydrogenated vegetable triglycerides with wax-like structures based on the listed waxes. The addition of non-hydrogenated waxes is also conceivable. One such hydrogenated wax is available, for example, under the trade name Polycerin 9548. 1) (Dropping point: 65 - 72°C; Acid value: max. 3 mg KOH / g). Further examples are available under the trade name Polycerin 9542 1) (Dropping point: 68 - 72°C; Acid number: max. 3 mg KOH / g) Polycerin RD 1)(dropping point: 55 - 61°C; acid number: max. 3 mg KOH / g) available wax.

[0017] The hardened wax or the hardened wax mixture is preferably contained in the lead base mass in a proportion of 2.0 to 30.0 wt.%.

[0018] A portion of the colored pencil lead, graphite lead, colored or graphite chalk is formed by at least one filler, wherein the use of the at least one filler with a proportion of 5.0 to 80 wt.% in the lead base mass has proven advantageous.

[0019] Inorganic, finely powdered fillers, especially talc, pumice, kaolin, mica, aluminum silicate, clay and / or calcium carbonate are particularly suitable as fillers, as these are particularly well bound in the lead matrix due to their polarity.

[0020] As a colorant, the lead base mass contains, in particular, at least one dye and / or at least one inorganic pigment and / or at least one organic pigment, with inorganic and / or organic pigments being preferred over dyes. Examples of inorganic pigments present include titanium dioxide, manganese violet, ultramarine, ferriferrocyanide, iron oxides, carbon black, or metallic pigments, e.g., aluminum. Organic pigments are preferably selected from the group of phthalocyanine, azo, quinacridone, isoindoline, and diketopyrrolopyrrole pigments.

[0021] A proportion of 0.1 - 50 wt.%, in particular a proportion of 0.1 - 40 wt.%, particularly preferably a proportion of 0.1 - 30 wt.% in the lead base mass has proven to be an advantageous use concentration for the at least one colorant.

[0022] Finally, it is also advantageous if the lead base contains at least one additive, in particular a lubricant and / or a dispersing agent, e.g., CAS 85711-47-3, CAS 108-31-6, CAS 398475-96-2, CAS 57472-68-1, CAS 14431-03-8. Examples of lubricants include fatty acid salts such as calcium stearate, magnesium stearate, zinc stearate, sodium stearate, or magnesium myristate.

[0023] Preferably, the proportion of the additive in the lead base mass is limited to a maximum of 5.0 wt.%.

[0024] The colored pencil leads are waterproof and can be manufactured in a two-step process. The raw materials of the lead, or the components of the lead base, can be mixed and extruded at low temperatures of approximately 110 to 140°C. This softens the two waxes to a consistency such that, despite the additional fillers and color pigments, lead strands with a diameter of 3 to 5 mm for colored pencil leads and up to 20 mm for colored crayons can be extruded.

[0025] The colored pencil lead is thus made from a lead base or starting compound containing the aforementioned components or raw materials, which is thermoplastically processed and extruded to melt and bind the raw materials. The resulting lead strands are then cut to length if necessary. After the lead mass has cooled, the finished lead is available; laborious water removal is not necessary.

[0026] In summary, the following basic recipe can be given for the colored pencil lead, graphite lead, colored or graphite chalk according to the invention: Aluminum distearate 0.4 - 10.0 wt.% Functionalized metallocene polyolefin wax 5.0 - 25.0 wt.% Hardened wax / wax mixture 2.0 - 30.0 wt.% Fillers 5.0 - 80.0 wt.% Colorants 0.1 - 50 wt.% Additive up to 5.0 wt.%

[0027] Six sample recipes are listed below. The weight percentages given in the sample recipes refer to the proportions in the lead base mass. The lead or chalk is manufactured in a two-stage process. First, the raw materials are mixed and homogenized in high-speed mixers, kneaders, or compounding extruders at mixing temperatures of 110–140°C. After mixing, the homogeneous mass is cooled to produce granules that are solid at room temperature. If necessary, additional mechanical comminution is carried out. The resulting granules are then fed into an extruder, such as a screw extruder, and the lead or chalk is formed in the screw extruder at temperatures of 130–140°C. The lead base mass is extruded into lead strands, which are then cut to length. Example 1A:

[0028] Example recipe for a blue colored pencil lead with a diameter of 4.0 mm: Aluminum distearate (CAS No. 300-92-5) 1.2 wt.% Ethylene-maleic anhydride copolymer (CAS No. 9006-26-2) 9.5 wt.% Hard vegetable wax Polycerin 9548 1) 12.3 wt% mica 15.0 wt.% kaolin 57.0 wt.% Pigment Blue 15:1, CI 74160 5.0 wt.% Example 1B:

[0029] Example recipe for a red colored pencil lead with a diameter of 4.0 mm: Aluminum distearate (CAS No. 300-92-5) 1.1 wt.% Ethylene-maleic anhydride copolymer (CAS No. 9006-26-2) 9.1 wt.% Hard vegetable wax Polycerin 9548 1) 11.8 wt.% mica 15.0 wt.% kaolin 58.0 wt.% Pigment Red 254, CI 56110 5.0 wt.% Example 1C:

[0030] Example recipe for a green chalk with a diameter of 12.0 mm: Aluminum distearate (CAS No. 300-92-5) 3.0 wt.% Ethylene-maleic anhydride copolymer (CAS No. 9006-26-2) 15.0 wt.% Hard vegetable wax Polycerin 9548 1) 25.0 wt.% talc 50.0 wt.% Calcium stearate 4.0 wt.% Pigment Green 7, CI 74260 3.0 wt.% Example 1D:

[0031] Example recipe for a yellow colored pencil lead with a diameter of 3.3 mm: Aluminum distearate (CAS No. 300-92-5) 5.0 wt.% Propylene-maleic anhydride copolymer (CAS No. 25722-45-6) 16.0 wt.% Hard vegetable wax Polycerin 9542 1) 30.0 wt.% kaolin 28.0 wt.% Magnesium myristate 4.0 wt.% Dispersing agent BYK Dispersplast 1142 2) 2.0 wt.% Pigment Yellow 42, CI 77492 15.0 wt.% Example 1E:

[0032] Example recipe for a yellow colored pencil lead with a diameter of 3.8 mm: Aluminum distearate (CAS No. 300-92-5) 4.5 wt.% Ethylene-maleic anhydride copolymer (CAS No. 9006-26-2) 15.0 wt.% Hard vegetable wax Polycerin 9548 1) 3.0 wt.% Titanium dioxide 8.0 wt.% kaolin 62.5% by weight Pigment Yellow 185, CI 56290 7.0 wt.% Example 1F:

[0033] Example recipe for a graphite lead with a diameter of 3.0 mm: Aluminum distearate (CAS No. 300-92-5) 7.0 wt.% Ethylene-maleic anhydride copolymer (CAS No. 9006-26-2) 20.0 wt.% Hard vegetable wax Polycerin RD 828 1) 15.0 wt.% Graphite powder 18.0% by weight clay 40.0 wt.%

[0034] To demonstrate the improvements achievable with the inventive leads compared to the prior art, comparative tests were conducted with leads according to EP 2 520 442 B1, i.e., leads without functionalized metallocene polyolefin wax, and leads according to EP 3 772 532 B1, i.e., leads without aluminum distearate. The comparative formulations are listed below: Comparison example 2A:

[0035] Comparative formulation 2A according to EP 3 772 532 B1 for a blue colored pencil lead with a diameter of 4.0 mm: Ethylene-maleic anhydride copolymer (CAS 9006-26-2) 9.5% by weight Oxidized Ethylene Vinyl Acetate (EVA) Wax (CAS 104912-80-3) 1.2 wt.% Hard vegetable wax Polycerin 9548 1) 12.3% by weight mica 15.0 wt.% kaolin 57.0 wt.% Pigment Blue 15:1; CI 74160 5.0 wt.% Comparison example 2B:

[0036] Comparative formulation 2B according to EP 3 772 532 B1 for a red colored pencil lead with a diameter of 4.0 mm: Ethylene-maleic anhydride copolymer (CAS 9006-26-2) 9.1 wt.% Oxidized Ethylene Vinyl Acetate (EVA) Wax (CAS 104912-80-3) 1.1 wt.% Hard vegetable wax Polycerin 9548 1) 11.8% by weight mica 15.0 wt.% kaolin 58.0% by weight Pigment Red 254; CI 56110 5.0 wt.% Comparison example 3A:

[0037] Comparative formulation 3A according to EP 2 520 442 B1 for a blue colored pencil lead with a diameter of 4.0 mm: Aluminum distearate (CAS 300-92-5) 1.2 wt.% Polyethylene wax with oxygen-containing functional groups (CAS 68441-17-8) 9.5% by weight Hard vegetable wax Polycerin 9548 1) 2.3% by weight mica 15.0 wt.% kaolin 57.0 wt.% Pigment Blue 15:1; CI 74160 5.0 wt.% Comparison example 3B:

[0038] Comparative formulation 3B according to EP 2 520 442 B1 for a red colored pencil lead with a diameter of 4.0 mm: Aluminum distearate (CAS 300-92-5) 1.1 wt.% Polyethylene wax with oxygen-containing functional groups (CAS 68441-17-8) 9.1 wt.% Hard vegetable wax Polycerin 9548 1) 11.8% by weight mica 15.0 wt.% kaolin 58.0% by weight Pigment Red 254; CI 56110 5.0 wt.%

[0039] To enable reproducible application of the leads to paper, a device for applying the leads to paper was used. This device allows six coats of color to be applied simultaneously and under comparable conditions to a painting surface, in this case paper. For this purpose, the leads are held in holders, subjected to a weight, and moved across the paper using the holder to create the coating. Experimental procedure

[0040] The machine used to apply graphite and colored pencil leads had test areas (fields) for six leads. Each field covered an area of ​​20.25 cm 2 applied, resulting in a total application area of ​​121.5 cm 2The tested leads had a diameter of 4.0 mm, were sharpened and a plateau of 1 mm 2 was created. The lead pieces were then clamped into the device's brass holders and loaded with a total weight of 570 g per lead (holder 66 g + loading weight 500 g + 4 g lead weight). The machine applied six square areas (each 20.25 cm 2 ), with the paint being applied 10 times from left to right and back.

[0041] The temperature during application was 21 °C (+ / - 1 °C), and the humidity was 50% relative humidity (+ / - 5%). The surface used was an A4 drawing pad, item no. 212046, Faber-Castell AG, D-90546 Stein near Nuremberg. Results of the comparative tests

[0042] First, the leads according to the inventive formulations 1A, 1B and according to the comparative formulations 2A, 2B, 3A and 3B were applied to the paper using the device shown.

[0043] From a purely visual perspective, a comparison of the variants according to 1A, 1B, 2A, 2B, 3A and 3B showed that the lead coatings according to the invention of the formulations 1A and 1B were more color-intensive than the comparison coatings of the previous state of the art (2A, 2B, 3A, 3B).

[0044] The results are summarized in the table below, with higher color intensity indicated by a higher number of “+”s: Table 1: Inventive mine Mines according to EP 3 772 532 B1 Mines according to EP 2 520 442 B1 1A (color "blue") 1B (color "red") 2A (color "blue") 2B (color "red") 3A (color "blue") 3B (color "red") Color intensity +++ +++ + + + +

[0045] By comparing the applied lead mass, an objective comparison can be demonstrated, as shown in the table below. To determine the applied lead mass, the paper was weighed before and after the lead was applied. The weight difference then corresponds to the applied lead mass: Table 2: Inventive mine Mines according to EP 3 772 532 B1 Mines according to EP 2 520 442 B1 1A (color "blue") 1B (color "red") 2A (color "blue") 2B (color "red") 3A (color "blue") 3B (color "red") applied lead mass 107 mg 84 mg 99 mg applied lead mass 110 mg 77 mg 97 mg • (1A+1B) 217 mg 161 mg 197 mg

[0046] The inventive leads thus allow higher lead mass quantities to be applied to paper. The inventive leads thus exhibit a softer application behavior.

[0047] In order to compare the covering power of the leads according to the invention with the cited prior art, the red leads were first applied to the test areas and then the blue leads were applied over them.

[0048] A visual comparison made it possible to demonstrate that the leads according to the invention produce more homogeneous surfaces and also offer better coverage than the leads according to the cited prior art. Here, too, better homogeneity or better coverage is indicated by a higher number of "+" symbols. Table 3: Inventive mine Mines according to EP 3 772 532 B1 Mines according to EP 2 520 442 B1 First, red 1B leads were applied. Then, blue 1A leads were drawn over them. First, red 2B leads were applied. Then, blue 2A leads were used to draw over them. First, red 3B leads were applied. Then, blue 3A leads were used to draw over them. homogeneity +++ + ++ Coverage +++ + ++

[0049] Here, too, the applied lead masses were compared to demonstrate an objective comparison: Table 4: Inventive mine Mines according to EP 3 772 532 B1 Mines according to EP 2 520 442 B1 First, red 1B leads were applied. Then, blue 1A leads were drawn over them. First, red 2B leads were applied. Then, blue 2A leads were used to draw over them. First, red 3B leads were applied. Then, blue 3A leads were used to draw over them. applied lead mass 173 mg 81 mg 127 mg

[0050] The test showed that significantly more lead mass was applied to the paper with the inventive leads than with the leads from the comparison formulations. The significantly higher total lead mass applied also indicates that the covering power of the inventive leads is higher than that of the comparison formulations.

[0051] In a further test with first applied blue leads and then overpainted with the red leads, the result could be confirmed according to Table 4. Table 5: Inventive mine Mines according to EP 3 772 532 B1 Mines according to EP 2 520 442 B1 First, blue 1A leads were applied. Then First, blue mi- First, blue mi- was drawn with red leads 1B over it 2A was applied. Then 2B was drawn over it with red leads 3A was applied. Then 3B was drawn over it with red leads applied lead mass 162 mg 116 mg 132 mg Manufacturer: 1) Wax & Ceresin-Fabriken Th. C. Tromm GmbH, D-50735 Cologne 2) BYK-Chemie GmbH, D 46462 Wesel QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2 520 442 B1 [0003, 0004, 0034, 0037, 0038, 0044, 0045, 0048, 0049, 0051] EP 3 772 532 B1 [0004, 0009, 0034, 0035, 0036, 0044, 0045, 0048, 0049, 0051] EP 2 520 042 B1

[0009]

Claims

[1] Coloured pencil lead, graphite lead, coloured or graphite chalk for painting and / or drawing with a lead base containing waxes, at least one filler and at least one colourant, characterized by that the lead base also contains aluminum distearate and at least one functionalized metallocene polyolefin wax and at least one hardened wax are contained as waxes. [2] Coloured pencil lead, graphite lead, coloured or graphite chalk according to claim 1, characterized by that aluminum distearate is contained in the mine matrix in a proportion of 0.4 to 10.0 wt.%. [3] Colored pencil lead, graphite lead, colored or graphite chalk according to one of claims 1 or 2, characterized by that at least one functionalized metallocene polyolefin wax is contained in the lead base mass in a proportion of 5.0 to 25.0 wt.%. [4] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized bythat the at least one functionalized metallocene polyolefin wax has a dropping point between 120 and 160 °C and an acid number between 16 and 50 mg KOH / g. [5] Colored pencil lead, graphite lead, colored or graphite chalk according to one of the preceding claims, characterized by that ethylene-maleic anhydride copolymer (CAS No. 9006-26-2) or propylene-maleic anhydride copolymer (CAS No. 25722-45-6) is contained as functionalized metallocene polyolefin wax. [6] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized by that the hardened wax has a dropping point between 50 and 120 °C (ISO 2176) and an acid number between 1 and 11 mg KOH / g (ISO 2114). [7] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized bythat the hardened wax contains palm wax, rapeseed wax, sunflower wax, soy wax, ester wax, synthetic beeswax, mantan wax, paraffin wax, natural waxes, carnauba wax and / or hydrogenated castor oil and / or hardened vegetable triglycerides with wax-like structures based on the listed waxes. [8] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized by that the hardened wax is contained in the lead base mass in a proportion of 2.0 to 30.0 wt.%. [9] Colored pencil lead, graphite lead, colored or graphite chalk according to one of the preceding claims, characterized by that at least one filler is contained in the lead matrix in a proportion of 5.0 to 80 wt.%. [10] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized bythat at least one inorganic filler, in particular talc, pumice powder, kaolin, mica, aluminum silicate, clay and / or calcium carbonate, and / or at least one organic filler, in particular cellulose fibers, wood fibers and / or textile fibers, and / or at least one inorganic pigment, in particular titanium dioxide, zinc oxide and / or barium sulfate, are contained as filler. [11] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized by that at least one dye and / or at least one inorganic pigment and / or at least one organic pigment (in the lead base mass) is contained as a colorant. [12] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized bythat the at least one colorant is contained in the lead base mass in a proportion of 0.1 - 50 wt.%, in particular a proportion of 0.1 - 40 wt.%, particularly preferably a proportion of 0.1 - 30 wt.%. [13] Coloured pencil lead, graphite lead, coloured or graphite chalk according to one of the preceding claims, characterized by that the lead base contains at least one additive, in particular a lubricant and / or a dispersing agent. [14] Coloured pencil lead, graphite lead, coloured or graphite chalk according to claim 13, characterized by that the additive is contained in the mine base mass at a maximum proportion of 5.0 wt.%.