EP2452827A1 - Method for coating the surface of a pin and pin with a surface coating - Google Patents

Abstract

The method involves applying a coating (5) on a part of a surface (3), where a partial surface area (6) of the coating comprises a carrier layer. The partial surface area emerges from the coating as a raised structure by the expansion of the particles. The thermoplastic polymer is softened at the expansion temperature, where a transfer layer comprises a transfer film. An independent claim is also included for a pin with a color layer.

Description

The invention relates to a method for coating the surface of a pin and a pin with a surface coating. Surfaces of pens, such as pens for writing, drawing and drawing purposes and cosmetic pens, are often provided with a paint coating, for example by spraying or dipping. For a visually pleasing surface of an object, further measures for surface design are usually required. It is also common for a coating to have special haptic properties, for example increased grip. The application of a coherent, the grip-increasing coating prepares usually no special difficulties. This is different if the grip of the surface is to be achieved by protruding surface regions of the coating, for example raised structures of non-slip masses in the form of knobs, ribs or the like.

At one off EP 1700713 B1 Known methods, a coating is applied to the surface of a pin, are contained in the thermally expandable particles, wherein a partial surface region of the coating is heated while at least a portion of the particles is brought to expand, whereby the partial surface regions protrude from the coating as raised structures. The raised areas enhance the grip of the pen and offer the possibility of the Stylus also in optical terms. However, they have the same color as the unexpanded areas of the coating, so that they do not differ visually from these clearly.

On this basis, it is the object of the invention to propose a method with which can produce in a technically simple manner on pens high-quality, optically and haptically pleasing coatings with raised areas of the type mentioned, which have a different color than non-raised areas of coating. Task is also to propose a pen with such a coating.

These objects are achieved by a method according to claim 1 and a pin according to claim 16. In the method according to the invention, a coating is applied to at least part of the pin surface, are contained in the thermally expandable particles. A partial area region of the coating is covered with a transfer film facing a carrier film and a thermoplastic polymer softening at the expansion temperature and a transfer film containing at least one colorant and heated to at least the expansion temperature of the particles by means of heat transfer through the transfer film whereby the partial surface area emerges from the coating as a raised structure due to the expansion of the particles and a part of the transfer layer is transferred to the raised structure.

An advantage of this approach is first that the staining of the raised structures in a single operation in the course The expansion of the corresponding partial surface areas can be done so that additional steps and necessary preparations are not required. A further advantage is that the raised structures can be colored with high accuracy. At the acted upon by the transfer film during the expansion process surface of the partial surface areas or the raised structures only one of the size of the contact surface of the heated body corresponding thermoplastic softened part of the transfer layer adhere, which in turn corresponds exactly to the size and shape of the raised structures. These always stand out with a sharp-edged outer contour from the unexpanded surface areas of the coating, even if they form filigree patterns on the pencil. In a subsequent coloring of the expanded surface areas by printing this would possibly be possible with a considerable procedural effort. Thus, an inaccurate orientation of the pen relative to the printing device and a different height of the expanded structures lead to an inaccurate and unclean appearance. As the partial surface areas of the coating expand, their volume increases, resulting in a relative movement between their surface and the transfer layer. At the moment of expansion, however, the thermoplastic-adjusted transfer layer is softened so that it can compensate for said relative movement. In contrast, commercially available hot stamping foils (eg Kurz, Nuremberg) can compensate for these relative movements only poorly and show cracking or adhesion problems. After removal of the heated body, the transfer layer cools rapidly, while it adheres firmly and stress-free to the raised structures. The adhesion is essentially ensured by the polymer of the transfer layer softened thermoplastic during the expansion process, so that one is free in this respect in the selection of the other components of the transfer layer, in particular the colorant. The thickness of the transfer layer is likewise freely selectable, with thinnest possible transfer layers being advantageous for maintaining the feel of the raised structures.

It is also advantageous that the feel of the raised areas is only very slightly influenced by the color layer. Decisive for the haptic is the surface structure, which must have sensible elevations of a certain size in order to achieve a pleasant grip for the fingers. The protruding from the surface after expanding, such as the spherical surfaces of hollow microspheres, lie in this area. There are soft touch, or velvety surfaces possible. If conventional hot stamping foils are used for coloring, the color layer transferred from the foil to the surface of the pen lies on top of the surface and covers these elevations. The grip effect is lost. When transferring a material that is liquid at the transfer temperature, the material flows into the surface or between the raised expanded particles, as a result of which they continue to protrude out of the surface, thus retaining the feel.

A further advantage is that the thermoplastically adjusted transfer layers behave relatively tolerantly with regard to their adhesion to the raised structures, ie that they form a material bond with a large number of different coating materials.

The proposed procedure results in a variety of design options, by producing in a technically simple manner on a surface of a pen, in particular a lead, color, drawing and cosmetic pencil, raised structures such as to increase the grip and / or for design purposes can be that stand out in color from unexpanded coating areas.

The expansion of the particles is preferably carried out in contact technology. In this case, a body is brought into thermal contact with a corresponding to the contour shape and area of the raised surface area of the coating, heated at least to the required expansion temperature contact surface of a body with the interposition of the transfer film, wherein the body or its contact surface expediently with a force against the coating to promote heat transfer and adhesion of the transfer layer to the raised structure produced. In a variant of the method, the body is moved away from the surface of a pin towards and after the expansion of the particles of a partial surface area. This variant, where the body is e.g. Is part of a Hubstempels, is particularly suitable for polygonal pins, such as for pens with triangular outline.

The expansion of the particles can also be effected without contact, for example by applying a high-energy light beam, for example a laser beam, to the partial area to be expanded, wherein at least one surface area intended for expansion is covered with a transfer film. To the transfer of heat-softened transfer layer to facilitate a raised structure, it may be convenient to push or pull the foil against the coating. The light spot produced by the light beam on the coating can be adapted to the desired shape of the raised structures by means of an optical system, for example.

A transfer film is produced in a simple manner by applying to a carrier film serving as a film, for example from a plastic, a flowable, containing a thermoplastic polymer and a solvent paint formulation or a paint or ink in the desired thickness and then dried. Preferably, an organic solvent is used, for example, to shorten the drying process. The viscosity of the preparation and the consistency can be influenced in a simple manner by adding a filler and the choice of the thermoplastic polymer or its concentration. Suitable fillers are, for example, talc, kaolin, barium sulfate, calcium carbonate, mica, silica, quartz powder and pumice.

As expandable particles are used in a preferred procedure, those having an expansion temperature of 110 ° C to 220 ° C. By expansion temperature is meant the temperature at which the particles increase their volume. Within the temperature range mentioned melt a plurality of thermoplastic polymers, so that there is a wide range of variation in the design of the transfer layer with respect to the polymers.

As expandable particles are preferably hollow microspheres, in particular those used in the unexpanded Condition have a mean particle size of 2 microns to 45 microns, with their diameter increases in the expanded state to about ten times. Hollow microspheres consist, for example, of a thermoplastic softenable polymer sheath, which encloses an easily evaporable liquid. When heated, the polymer material softens and the hollow microsphere is inflated by the liquid evaporating inside. The expanding hollow microspheres thus lead to an increase in volume of the coating, resulting in raised structures or surface areas.

Apart from hollow microspheres, however, the use of inorganic particles such as expanded mica or, in particular, expandable graphite or of particles of expandable plastics is also conceivable. There may also be several different expandable particles, such as those of the type mentioned, in the coating of a pen.

The application of the coating on the pin surface is easily possible for example by dipping, spraying, brushing, with the puncture process or by screen printing. The latter method is suitable, for example, if only partial areas of the surface are to be provided with a coating containing expanding particles. In a puncture method, for example, wood-sheathed pins are inserted via an input opening into a container containing liquid coating material, the pins leaving the container again via an exit opening, on which superfluous coating material is stripped off. After drying or already in the uncured state of the coating, the particles of a certain partial surface area are converted into their expanded state by the action of heat. In cases of pins with a round or oval cross-section, the expansion of the particles is preferably carried out by unrolling the object to be treated on the contact surface of a body heated at least to the expansion temperature. With this rolling technique, it is also possible to produce raised structures in complex patterns in a technically simple manner.

Fig. 1A,B

eine erste Verfahrensvariante zur Oberflächenbeschichtung eines Stiftes,

Fig. 2

eine zweite Verfahrensvariante zur Oberflächenbeschichtung eines Stiftes,

Fig. 3

den Ausschnitt III aus Fig. 2.

A solving the above-mentioned object pin is at least partially provided on its surface with a coating, which contains expandable particles. In one or more sub-area regions, the particles are expanded, whereby the sub-area regions protrude from the coating as raised structures. These are provided on their surface with a layer containing a thermoplastic softenable polymer and a colorant. As already described above, in addition to the advantageous simple production in particular the design degree of freedom for the surface design of the pins should be emphasized. For example, the respective proportion of the raised or non-raised partial surface areas may vary. Raised partial surface areas can, for example, form the much larger part of the coated pin surface, ie the flavor-influencing elements of the coated surface are formed by the non-raised coating areas which appear as depressions, for example in the form of a lettering. On the other hand, the raised areas may form a more or less filigree pattern, contrasting with the color of the non-raised coating and shaping the overall visual impression. The invention will now be explained in more detail with reference to the accompanying drawings. Shown schematically in each case:

Fig. 1A, B

a first process variant for the surface coating of a pencil,

Fig. 2

a second process variant for the surface coating of a pencil,

Fig. 3

the section III Fig. 2 ,

A pin 1, comprising a, for example made of wood, centrally a mine 2-bearing shaft 11, the surface 3, ie its peripheral surface to be provided with raised surface areas or structures 4.4 a, is first with a coating containing expandable particles. 5 Provided. In this case, the coating is applied to the entire surface 3 or only to a surface region forming, for example, a shaft longitudinal section. By way of example, reference will be made below to a coating 5 containing hollow microspheres as expandable particles. For example, hollow microspheres with a sheath of a mixed polymer (CAS No. 25214), which are available from Akzo Nobel Chemicals GmbH, D-46446 Emmerich, are suitable. For example, a preparation according to the examples given below can be used as starting material for the coating. In the case of a pen 1, which is to be provided with a total coating 5, the above briefly described puncture method is suitably used. If, on the other hand, only partial areas of the surface 3 are to be provided with a coating 5, this can be done, for example, by means of a screen-printing or spraying process. After the coating 5 approximately by air drying at a temperature above room temperature Temperature is hardened, a selective expansion is made. For this purpose, a partial surface region 6 of the coating 5 is heated to a temperature which is above the expansion temperature of the particles or hollow microspheres used in each case. The size of the partial area 6 corresponds essentially to the size or area of a later raised structure 4, 4a.

At the in Fig. 1 shown method variant, a punch 7 with a plurality of heatable contact surfaces 8 having bodies 9 is used for the expansion of the particles. The heating of the contact surfaces can be done for example by means of an electrical resistance heater. The punch is moved in the direction of the pen, which is indicated by the arrow 10. Between the contact surfaces 8 and the coating 5, a transfer film 13 is arranged. The heat supply to the coating thus takes place through the transfer film. This is acted upon by the bodies 9 and their contact surface 8 and pressed against the coating 5 with a certain force. The bodies 9 or their contact surfaces 8, 8a are heated to a temperature which is equal to or greater than the expansion temperature of the hollow microspheres. The expansion temperature is in a range of 110 ° C to 220 ° C. The hollow microspheres given in Examples 1 to 3 have an expansion temperature of about 180 ° C.

The contact surfaces 8 are substantially adapted to the contour of the surface to be treated, for example, in a circular cylindrical pin shaft cylindrical in shape, wherein the axis of curvature in the direction of the central longitudinal axis 10 of the pin 1 extends. The cross-sectional shape of a raised structure 4,4a can be explained to some extent by the shape of the Influence contact area 8. As in Fig. 1 is indicated by the dashed line, the contact surface 8a can be tolerated approximately cup-shaped, whereby a raised structure 4a is formed with a spherical shape.

The above-mentioned transfer film 13 is composed of a carrier layer 14 and a transfer layer 15. The carrier layer 14 is a film of a plastic, for example with a thickness of 12 microns. Such a film is e.g. available from the company Leonhard Kurz Foundation & Co KG, Nuremberg. The transfer layer 15 is prepared by applying a thermoplastic, i. at least one thermoplastic polymer-containing paint preparation, such as an ink or a paint, produced on the carrier layer 14. The color preparation is, for example, knife-coated or sprayed onto the carrier layer 14 and then dried, for example in a circulating-air oven at 60 ° C. The color preparation may e.g. be sprayed onto the carrier film via nozzles, with doctor blades, with fiber tips, but also via conventional inkjet printing systems. The transfer layer 15 has, after drying, e.g. a thickness of 8 microns.

The at least one thermoplastic polymer contained in the transfer layer softens at the above-mentioned expansion temperatures, whereby the softened transfer layer regions with a size corresponding to the contact surface 8, 8a connect to the raised structures in a material-locking manner, at least to a certain extent. Subsequently, when the punch 7 and the body 9 are removed from the pin 1, a corresponding to the size of the contact surface 8, 8a, at this time thermoplastic softened area of the transfer layer 15 dissolves, wherein a color layer 16 on the surface of a raised structure 4, 4a forms. At the location of the original transfer layer 15, from which the color layer 16 has peeled off, a depression 17 with a size corresponding to the detached color layer is formed.

In order to change the haptics of the raised structures as little as possible, the transfer layer 15 and, accordingly, the color layer 16 removed from the carrier layer 14 and adhering to the structures should be as thin as possible. The molten ink layer 16 in the heated state flows mainly between the hollow hollow microspheres 18 projecting from the surface of the raised structures 4, 4a (see FIG Fig. 3 ), so that the feel of the raised structures 4, 4a is caused substantially by the regions of the hollow microspheres 18 projecting from the surface of the structures 4, 4a and less by the color layer 16. The thinner the transfer layer 15 is, the easier it is to transfer a color layer 16 to a raised structure 4, 4a and the greater the edge sharpness of the color layer 16. The melting point or the lower temperature value of the melting range of the polymers present in the transfer layer 15 should be as far as possible be low, best clearly below 150 ° C, so that the transfer layer 15 softens as quickly as possible.

In Fig. 2 is a method variant which is particularly suitable for the coating of pins 1 with circular cylindrical or oval cross-sectional shape is shown schematically. The pin 1 is unrolled on the heated contact surface 8a of a body 9a, wherein between the coating 5 and the contact surface 8a, the transfer film 13 is arranged. When unrolling the pin 1 is provided with a partial surface area intended for expansion 6 slightly pressed against the contact surface 8a, whereby the adhesion of a detaching from the transfer layer 15 of the transfer film 13 ink layer 16 on a raised structure 4, 4a is favored. In the method variant shown, a plate-shaped tool 19 is used, in which a plurality of bodies 9a are integrated in a pattern corresponding to the pattern to be achieved from raised structures 4, 4a. The contact surfaces 8a of the body 9a are aligned with an eg flat surface 20 of the tool 19. The size of the contact surfaces 8a corresponds to the size of the raised structures to be generated 4. The relative speed between the pin 1 and the tool 19 depends on the desired contact duration between the Coating 5 and the contact surface 8a of a body 9a. The thermal treatment in the coating 5 can also be carried out so that the pin is held stationary and rotatable about its central longitudinal axis 10, wherein the tool 10 is moved, for example in the direction of the arrow 23.

As coating 5, the following formulations may be considered (percentages are by weight):

Water-based paint:

For the puncture process suitable paint. Binder: aqueous polyurethane dispersion (Alberdingk APU 1061) 1) 83% Polyurethane thickener (Rheolate 255) 2) 1 % Polyurethane thickener (Rheolate 244) 2) 2.3% Dispersing additive (Disperbyk-192) 3) 1 % Expandable hollow microspheres (Expancel 551 DU40) 4) 9% Wetting agent (Tego Wet 510) 5) 0.3% Mineral oil-based defoamer (Drewplus T 4202) 6) 0.4% aqueous pigment preparation (Levanyl Blue G-LF) 7) 3%

Colorless water-based topcoat:

Binder: aqueous polyurethane dispersion (Alberdingk U 210) 1) 80% expandable hollow microspheres (Expancel 820 SL 40) 4) 18% Polyurethane thickener (Rheolate 244) 2) 1.5% Thickener (DSX 3290) 8th) 0.2% Mineral oil-based defoamer (Drewplus T 4202) 6) 0.3%

Colored UV-curable lacquer:

UV binder: (Genome 1343) 9) 13% Polymerization inhibitor (Genorad 16) 9) 0.3% UV binder (Genome 5275) 9) 11% Thickener (Aerosil 380) 10) 0.3% UV binder, (Specialty Resin 01-554) 9) 16% UV photoinitiator (Irgacure 819) 11) 1 % UV photoinitiator, (Darocur 1173) 11) 2% UV pigment preparation, (Microlith Black C-K) 11) 0.5% Defoamer (Byk 020) 3) 0.2% Softfeeling additive (Daiplacoat RHC-731 Clear) 12) 11% Matting agent (Syloid Rad 2105) 13) 3% UV binder, (Genomer 6050 / TM) 9) 29% Expandable hollow microspheres (Expancel 551 DU 40) 4) 12.7%

Colorless solvent-based topcoat:

Binding agent (nitrocellulose H 22) 14) 19% Plasticizer based on tributyl citrate (Citrofol A 1) 4) 5% Resin binder, (Kunstkarz SK) 15) 6% Solvent (acetone) 16) 60% expandable hollow spheres (Expancel 091 DU 120) 4) 10%

Water-based paint:

For the screen printing suitable paint. Binder: aqueous polyurethane dispersion (Liopur 97-282) 17) 50.6% Polyurethane thickener (Rheolate 244) 2) 3% aqueous pigment preparation (Levanyl Blue G-LF) 7) 0.7% aqueous pigment preparation (Levanox white RNZ-SF) 7) 5% Solvent (1,2-propanediol) 18) 10% Defoamer (EFKA 2526) 19) 0.7% Expandable hollow microspheres (Expancel 091 DU 140) 4) 30%

The following formulations are considered as examples for the transfer layer:

Recipe 1:

Butyglycol acetate (solvent) 20) 27.1% GB ester (solvent) 20) 10.6% Anon pure (solvent) 20) 26.3% Microlith Green G-T (colorant) 22) 2.1% Microlith Yellow 2G-T (colorant) 22) 2.5% Microlith White R-K (colorant) 22) 3.0% Finntalc M03-AW (filler) 23) 5.9% Synthetic resin AP (polymer) 10) 14.0% Mowital B 20 H (polymer) 24) 8.5%

Recipe 2:

Alcohol (solvent) 21) 56.6% 3-methoxy-1-butanol (solvent) 30.4% Savinyl Red 2BLSE (colorant) 25) 4.3% Mowital B 20 H (polymer) 24) 1.1% Rokrapol 7160 (polymer) 26) 7.6%

Recipe 3:

Alcohol (solvent) 21) 72.0% 3-methoxy-1-butanol (solvent) 18.0% Savinyl Red 2BLSE (colorant) 25) 2.0% Resin SK (polymer) 10) 8.0%

Manufacturer:

1. 1) Alberdingk Boley GmbH, D-47829 Krefeld
2. 2) Elementis, Ambachtsweg 8, 4906 CH Oosterhout, The Netherlands
3. 3) Byk Chemie GmbH, D-46462 Wesel
4. 4) Akzo Nobel Chemicals GmbH, D-46446 Emmerich
5. 5) Tego Chemie Service GmbH, D-45127 Essen
6. 6) Drew Ameroid Germany GmbH, D-63073 Offenbach
7. 7) Bayer AG, D-51368 Leverkusen
8. 8) Cognis Germany GmbH, D-40551 Dusseldorf
9. 9) Rahn AG, CH-8050 Zurich
10. 10) Degussa AG, D-60287 Frankfurt a. M.
11. 11) Ciba, CH-4002 Basel
12. 12) Gustav Grolman GmbH & Co. KG, D-41468 Neuss
13. 13) Grace Davison Europe, D-67547 Worms
14. 14) Hagedorn AG, D-49078 Osnabrück
15. 15) Degussa Hüls / Creanova Spezialchemie GmbH,
    D 53859 Niederkassel
16. 16) Biesterfeld Spezialchemie GmbH, D-20095 Hamburg
17. 17) Synthopol Chemistry, D-21605 Buxtehude
18. 18) Merck KGaA, D-64293 Darmstadt
19. 19) EFKA Additives B.V., 8440 AN Heerenveen, Netherlands
20. 20) CSC Jäcklechemie, D-90431 Nuremberg
21. 21) Staufen Chemie, D-73110 Hattenhofen
22. 22) BASF, Ludwigshafen
23. 23) MONDO MINERALS B.V., NL-1041 AR, Amsterdam
24. 24) Kuraray, D-65926 Frankfurt a. M.
25. 25) Clariant, Frankfurt a. M.
26. 26) Robert Kraemer GmbH & Co. KG, D-26180 Rastede

Claims (20)

Process for the surface coating of a pin (1), in which at least on a part of the surface (3) a coating (5) is applied in which thermally expandable particles are contained, - A partial surface area of the coating (5) with a carrier layer (14) and one of the coating (5) facing, a softening at the expansion temperature thermoplastic polymer and at least one colorant-containing transfer layer (15) having covered transfer film (13) and with help a heat input through the transfer film is heated at least to the expansion temperature of the particles, whereby the partial surface area emerges from the coating (5) due to the expansion of the particles as a raised structure (4, 4a) and a part of the transfer layer (15) to the raised one Structure is transferred. Method according to claim 1,
characterized,
that the partial surface area of the coating (5) with a heated at least to the expansion temperature contact surface (8, 8a) of a body (9, 9a) with the interposition of the transfer foil (13) brought into thermal contact. Method according to claim 2,
characterized,
in that the body (9) is moved away from the partial surface area towards the coating (5) and after the expansion of the particles. Method according to claim 3,
characterized,
that it is used for cross-section polygonal pins. Method according to claim 2,
characterized,
in that a pin (1) with a round or oval cross-section is unrolled on a heated contact surface (8a) of a body (9a). Method according to claim 1,
characterized,
that the heat supply is contactless. Method according to claim 6,
characterized,
in that a partial area covered by a transfer film (13) is exposed to a light beam. Method according to claim 7,
marked by
the use of laser light. Method according to one of the preceding claims,
marked by
the use of a transfer film (13) having a transfer layer (15), the latter containing, by applying a flowable, a thermoplastic polymer and a solvent paint formula is applied to the carrier layer (14) and generated by subsequent drying of the paint formula. Method according to claim 9,
characterized,
that the ink composition contains an organic solvent. Method according to one of the preceding claims,
marked by
the use of a transfer film (13) whose transfer layer (15) contains a filler. Method according to one of the preceding claims,
marked by
the use of thermally expandable particles with an expansion temperature of 110 ° C to 220 ° C. Method according to claim 12,
characterized,
that hollow microspheres are used as thermally expandable particles. Method according to claim 13,
characterized by hollow microspheres with an average size of 2 microns to 45 microns in the unexpanded state. Method according to one of the preceding claims,
characterized,
that on the surface (3) of a wood-filled pin (1) raised structures (4, 4a) are generated. Pin whose surface (3) is at least partially provided with a coating (5),
characterized,
in that the coating (5) contains expandable particles such that the particles are expanded in a partial surface area of the coating (5), whereby the partial surface area protrudes out of the coating as a raised structure (4, 4a) and the raised structure forms a surface on its surface thermoplastic softenable polymer and a colorant-containing ink layer (16) is provided. A pen according to claim 16,
characterized,
that the layer contains a filler. A pen according to claim 16 or 17,
characterized,
that the coating (5) contains hollow microspheres as expandable or expanded particles. A pen according to claim 18,
characterized,
that the hollow microspheres in the initial state have an average particle size of 2-45 microns and are at least doubled in the expanded state. A pen according to any one of claims 16 to 19,
characterized,
that the pin (1) is a wood-clad pin.

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