ERASABLE, UNBURNT COLORED LEAD FOR WRITING, DRAWING AND PAINTING DEVICES OR ERASABLE, UNBURNT COLORED CHALK, WRITING, PAINTING OR DRAWING DEVICE COMPRISING AN ERASABLE, UNBURNT COLORED LEAD AND METHOD FOR MANUFACTURING AN ERASABLE, COLORED LEAD OR CHALK

Abstract

The invention relates to an erasable, unburnt colored lead for writing, drawing and painting devices or erasable, unburnt colored chalk containing at least one filler material, graphite, at least one colorant, at least one binding agent and at least one wax, wherein boron nitride is present as a filler material and at least on pigment is present as colorant. The invention further relates to a writing, painting or drawing device comprising an erasable, unburnt colored lead and a method for manufacturing such a colored lead or colored chalk.

Claims

1. Erasable, unburnt colored lead for writing, drawing and painting devices or erasable, unburnt colored chalk containing at least one filler material, graphite, at least one colorant, at least one binding agent and at least one wax, in particular at least two types of waxes, wherein boron nitride is present as a filler material and at least one pigment is present as colorant.

2. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein the at least one colorant is present in an amount between 0.5 and 25% by weight, preferably in an amount between 0.5 and 20% by weight.

3. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein at least one dye and at least one pigment are present as colorant.

4. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein at least one pH stabilizing agent is present, in particular wherein the at least one pH stabilizing agent is present in an amount between 0.1 and 4.0% by weight.

5. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein the at least one filler material is present in an amount between 40 and 80% by weight.

6. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein graphite is present in an amount between 1.0 and 3.0% by weight.

7. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein the at least one wax is present in an amount between 10.0 and 50.0% by weight.

8. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein the at least one wax has a melting point below 70 C.

9. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein at least two types of waxes with different length of carbon chains are present, in particular waxes comprising a C16 chain and waxes comprising a C18 chain are present.

10. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 9, wherein waxes comprising a C16 chain are present in an amount between 20.0 and 35.0% by weight and waxes comprising a C18 chain are present in an amount between 60.0 and 80.0% by weight within the total percentage of weight of the amount of waxes in the lead or chalk.

11. The erasable, unburnt colored lead or erasable, unburnt colored chalk according to claim 1, wherein the at least one binding agent is present in an amount between 5.0 and 20.0% by weight and/or wherein cellulose derivatives or other derivatives of natural polymers are present as binding agent.

12. A writing, painting or drawing device comprising an erasable, unburnt colored lead according to claim 1, wherein the device is a mechanical pencil or a pencil comprising a sheath made of wood or made of a wood substitute material surrounding the erasable, unburnt colored lead.

13. A method for manufacturing an erasable, colored lead or erasable, colored chalk, in particular according to claim 1, comprising the following method steps: a) mixing and homogenizing the at least one filler material, the at least one colorant, the graphite, the at least one binding agent and the at least one wax thereby forming a lead- or chalk base mass, b) extruding the lead- or chalk base mass, in particular by means of hydraulic pressing thereby forming lead or chalk strands, c) drying the extruded lead or chalk strands.

14. The method for manufacturing an erasable colored lead or erasable, colored chalk according to claim 13, wherein step a) comprises the following sub-steps: a1) mixing the at least one filler material, the graphite, the binding agent and the at least one colorant, in particular for 25-35 min, a2) adding the at least one wax and water, a3) heating the mixture to a temperature 50-60 C. and maintaining the temperature for 120 min, a4) cooling the mixture to a temperature of 40-46 C.

15. The method for manufacturing an erasable colored lead or erasable, colored chalk according to claim 13, wherein step c) comprises drying the extruded lead or chalk strands at a temperature between 40-70 C.

Description

Example 1: Erasable Part: Pink/Permanent Part: Pink

TABLE-US-00003 Raw Material Percentage (%) Boron Nitride .sup.1) 42.30 Pigment Red 122 .sup.4) 2.00 Sanolin Ponceau Dye .sup.7) 1.40 Graphite .sup.3) 1.40 Hydrogenated Palm Oil .sup.9) 20.40 Stearic Acid .sup.11) 10.00 Paraffin Wax .sup.8) 17.20 Lactic Acid .sup.15) 0.30 Cellulose Derivative .sup.14) 5.00 TOTAL: 100.00

[0065] A colored lead according to example 1 shows great softness, good erasability and good lightfastness.

Example 2: Erasable Part: Green/Permanent Part: Green

TABLE-US-00004 Raw Material Percentage (%) Boron Nitride .sup.1) 75.9 Pigment Blue 15:3 .sup.5) 0.90 Pigment Yellow 13 .sup.6) 0.60 Tartrazine Dye (Yellow 5) .sup.18) 1.10 Brilliant Blue Dye .sup.16) 1.50 Graphite .sup.3) 2.00 Stearic Acid .sup.11) 2.20 Hydrogenated Soybean 3.80 Oil .sup.10) Hydrogenated Palm Oil .sup.9) 4.20 Lactic Acid .sup.15) 0.50 Cellulose Derivative .sup.14) 7.30 TOTAL: 100.00

[0066] A colored lead according to example 2 comprises boron nitride in an amount of 75.9 wt.-% and therefore shows high erasability.

Example 3: Erasable Part: Purple/Permanent Part: Blue

TABLE-US-00005 Raw Material Percentage (%) Boron Nitride .sup.1) 43.00 Calcium Stearate .sup.19) 3.40 Graphite .sup.3) 1.00 Pigment Red 122 .sup.4) 9.10 Brilliant Blue Dye .sup.16) 5.00 Hydrogenated Castor Oil .sup.13) 10.00 Hydrogenated Soybean 10.00 Oil .sup.10) Beeswax .sup.12) 2.30 Lactic Acid .sup.15) 1.20 Cellulose Derivative .sup.14) 15.00 TOTAL: 100.00

[0067] A colored lead according to example 3 has great mechanical resistance and great lightfastness.

Example 4: Erasable Part: Blue/Permanent Part: Blue

TABLE-US-00006 Raw Material Percentage (%) Boron Nitride .sup.1) 56.20 Kaolin .sup.2) 2.50 Graphite .sup.3) 2.60 Pigment Violet 23 .sup.17) 3.10 Pigment Blue 15:3 .sup.5) 6.60 Brilliant Blue Dye .sup.16) 2.00 Hydrogenated Castor Oil .sup.13) 6.00 Hydrogenated Soybean 5.00 Oil .sup.10) Hydrogenated Palm Oil .sup.9) 5.40 Lactic Acid .sup.15) 0.35 Cellulose Derivative .sup.14) 10.25 TOTAL: 100.00

[0068] A colored lead according to example 4 shows great lightfastness and good erasability.

[0069] The amounts are in percent by weight and indicate the proportion of each individual substance in the raw materials as well as in the lead itself.

Product Names/Manufacturers

[0070] Boron nitride (CAS No. 10043-5; example 1: Trs BN PUPH500, Saint Gobain; example 2: Boron Nitride Powder LN05, Zibo Kevins Ceramic Materials Co., Ltd.), [0071] Kaolin (CAS No. 1332-58-7; example 1: SAZ003, Imerys; example 2: ASP 602, Basf), [0072] Graphite (CAS No. 7782-42-5; example 1: Natural Flake Graphite, MG94, Unimate; example 2: Micrograf 9425MA, Nacional de Grafite), [0073] Pigment Red 122 (CAS No. 16043-40-6, CI 73915; example 1: PV Fast Pink E 01, Heubach; example 2: Alpafast Pink E PL-2745, Meghamani Pigments) [0074] Pigment Blue 15:3 (CAS No 147-14-8, CI 74160; example 1: Pigment Heliogen Blue D 7079, BASF; example 2: Monolite Blue 515303, Heubach), [0075] Pigment Yellow 13 (CAS No. 5102-83-0, CI 21100; example 1: Pigment Sunbrite Yellow 13, SunChemical Corporation; example 2: Pigment Lilyperm Yellow 1148 A, Lilly Group CO, Ltd.) [0076] Sanolin Ponceau (CI 16255; example: Sanolin Ponceau 4RC 82, Heubach Colorants Brasil Ltda) [0077] Paraffin Wax (CAS No. 63231-60-7; example 1: Solven Wax 170, Solven; example 2: ISOCER A07-2, Isogama) [0078] Hydrogenated palm oil (CAS No. 68514-74-9; example 1: Hydrogenated palm oil, Industrias Xhara Ltda.; example 2: Hydrogenated palm oil, A. Azevedo Ind. E Com. De leos Ltda.) [0079] Hydrogenated soybean oil (CAS No. 8016-70-4; Manufacturers examples: Industrias Xhara Ltda.; A. Azevedo Ind. E Com. De leos Ltda.) [0080] Stearic acid (CAS No. 93028-76-3; example 1: Stearic Acid-TPOS, Vegetallis Indstria E Comrcio Ltda.; example 2: Azecid 1885, A. Azevedo Ind. E Com. De leos Ltda.) [0081] Beeswax (CAS No. 8012-89-3), Manufacturers examples: Wenzel [0082] Castor Oil Hydrogenated (CAS No. 8001-78-3, Manufactures example: A. Azevedo Ind. E Com. De leos Ltda.; Campestre [0083] Cellulose derivatives: Example 1: HPMC hydroxypropyl methyl cellulose (CAS No. 9004-65-3), Shandong Head Group Co., Ltd.; example 2: Carboxymethylcellulose (CAS 9004-32-4), Denvercell, Denver Especialidades Qumicas) [0084] LACTIC ACID PA (CAS No. 50-21-5), Manufacturers examples: Exodo; MERCK [0085] Brilliant Blue dye (CI 42090), Manufacturers examples: Plury Qumica Ltds.; Plentychem Indstria e Comercial [0086] Pigment Violet 23 (CAS No. 6358-30-1), Example 1: Pigment Alpafast Violet RL AS 3609, Meghamani Organics Ltd; example 2: Pigment Chromophtal Violet D 5800, BASF [0087] Tartrazine Dye, Yellow 5 (CAS No. 1934-21-0, CI 19140); example 1: PLURY QUMICA LTDA, example 2: Heubach Colorants Brasil Ltda. [0088] Calcium Stearate (CAS No. 1592-23-0), Manufacturers example: ADVANT INDSTRIA COMRCIO IMPORTAO E EXPORTAO DE PRODUTOS QUMICOS; BAERLOCHER.