DE7919836U1 - HEAT PLATE - Google Patents

Description

-z-

Heating plate

: 'Heat plates are known in various designs, as in ; the shape of flat plates with handles for placing on a table. Other hot plates have legs or themselves Rolls in the shape of a side table or Teewa.yans. the Legs can also be foldable.

As is known, hot plates are usually heated electrically and have an electrical connection for this purpose. But there are also hot plates, especially for restaurants, which are in be preheated in an electric oven and have their own heating device.

What all these hot plates have in common is that they are a heating surface, usually made of thermally conductive metal, on which a vessel with the food to be heated or the »to be heated Drink is put on.

It is also already known to provide the heating surface of such heating plates with a heat-resistant plastic coating. Such plastic coatings cannot be provided with pictures or at best equipped with simple line ornaments will.

The task on which the innovation is based now consisted of
To get hot plates, on their heating surface at least
a dye is arranged to image-wise or pattern-shaped, _t that halftone technique, and thus a high quality image is möglicn.

According to the innovation are the hot plates, the hot surface of which one
Has plastic coating, characterized in that in the
Plastic cover lying directly on the heating surface
adjacent to its free surface in limited areas; at least one dye is arranged. j

Such hot plates are clearly different from product!

i sen, which were decorated by screen printing, as the screen printing process \

drive the dye rests directly on the heating surface

and over it there would be a layer of varnish. At the \

The subject of the innovation, however, are the dyes as such

art arranged in the plastic coating itself that it is of \

its free surface in the direction of the heating surface, |

usually a metal surface, are diffused. §

It is useful here that the dye or dyes * are arranged in the plastic coating in such a way that they adjoin each other on its free surface over only part of the
Extend thickness of the plastic coating. That is, the art *
The fabric cover is free of dye in its area adjacent to the heating surface, while this is in the area of the

Concentrated free surface of the plastic coating facing away from the heating surface.

• · ♦ ♦ · · I

• · «■

The heating plates according to the invention can be produced in such a way that they are first coated on the heating surface with a suitable, ie preferably abrasion-resistant, hard and heat-resistant plastic and then the dye or dyes are printed on in the transfer printing process with the application of heat. The per se known transfer printing process is followed in that the desired figure initially reversed to an auxiliary support such as paper, printed 'is. To transfer this image to the heating surface of the heating plate, the auxiliary carrier with the imprint on the plastic coating of the heating surface is placed on the latter, whereupon the dyes are transferred to the surface of the plastic coating of the heating surface by applying a hot roller or plate and from there via a diffuse into the plastic coating in a limited area.

With this method you can get images with the highest print quality and transferring sharpness to the hot surface of the hot plate, preferably using a half-tone technique.

The hot plates can be any of the type described at the outset and, for example, have legs or rollers. The heating surface usually consists of steel or another thermally conductive material, such as a ceramic material.

The plastic coating on the heating surface of the heating plate can consist of a thermoplastic material, the opposite

- 6 -

is affine to the printing inks to be used and prevents migration of the printing inks after printing as much as possible to prevent the images from becoming unscreened over time. Examples of such plastics are polyacrylonitrile, polyesters, polyurethanes, cellulose derivatives such as cellulose acetate and nitrocellulose, Phenoplasts and aminoplasts, epoxy resins, polyamides, such as polycaprolactam, polyundecanamide, polyhoxamethylene adipamide and others, and among these plastics, nonlinear polyurethanes and polyesters are particularly preferred.

It is particularly useful to use plastic coatings from a cross-linked To use thermosets. These cross-linked thermosets can be, for example, phenoplasts, aminoplasts, epoxy resins, Be silicone resins, acrylic resins, alkyd resins or unsaturated polyester resins. The networking of these or other thermosets can be done in different ways. Crosslinking agents are used which are capable of breaking the linear molecular chains of the precursor of the crosslinked thermoset initially applied to the heating surface with reactive centers through formation to convert intermolecular bridges into networks of three-dimensional structure. The crosslinking agents can either can themselves be built into the network as intermolecular bridges or a direct union of reactive centers of Activate chain to chain.

A particularly favorable group of thermosets is that of the silicone resins, especially those with methyl, ethyl and phenyl substituents. Depending on the substituents, they are water-repellent and

hardly flammable, show good dimensional stability at high temperatures and have a good surface hardness in addition to an excellent affinity for those to be used Disperse dyes.

The embedded in the plastic coating dyes are useful, those above 220 ⁰ C, particularly above 250 ⁰ C, preferably sublimate above 3OG ⁰ C and particularly preferably above 350 ° C. When using such dyes, especially in connection with cross-linked thermosetting plastics as a plastic coating, images are obtained on the heating surface that, even with prolonged and frequent heating, as inevitably occurs when using the heating plate, no dye migration in the plastic coating and thus no blurring of the printed matter Images. In other words, the use of the preferred dyes and plastic coatings results in the dyes in the plastic coating retaining the position in which they were placed in the transfer printing process. For manufacturing reasons, however, it is advisable to select those dyes which do not sublime ^{above 500 °} C., preferably not above 400 ^{° C.}

The disperse dyes used are expediently to high molecular weight disperse dyes with molecular weights above 280, preferably above 340 and up to Molecular weights of 1000. A preferred group of such disperse dyes are certain anthraquinone, monoazo and azomethine dyes, but the process of the invention is not

limited to these dye groups. ||

While the | Colorants no ionic, highly water-solubilizing | Groups such as —SO ₃ H or —COOH may be included, such dyes can be used successfully in the process according to the invention. The number of non-ionic polar groups, such as -NO ₂ , -CN, -SO ₂ R (R = alkyl), -OH, -NH ₂ or -NHR (R = alkyl), can also be higher than the previously usable ones Dyes. In addition to alkyl-substituted amino groups, such as isobutylamino groups, linear pests can also be present, which has hitherto been avoided in the transfer printing process. For azo dyes, cyano groups are preferred to nitro groups, and fluorine atoms are better than chlorine atoms. Trimethylsilyl groups can increase the vapor pressure in the azo dyes.

In summary, with regard to the disperse dyes which can be used say that in the process according to the invention, in contrast to known transfer printing processes, now so-called Sublime-fast disperse dyes can be used. Anthraquinone, monoazo and azomethine dyes are preferred, whose molecules are heavily occupied with amino, alkoxy, oxalkyl, nitro, halogen and cyano groups. These dye groups are defined in Color Index, Volume 1, pages 1655 to 1742.

# I I ti

• ■% f

Other useful dyes are anthraquinone dyes, such as hydroxy and / or aminoanthraquinones, azo dyes, quinophthalone dyes, Azomethine dyes, sti.lben dyes, Ni trodiarylaminf arbs tof fe, etc. Such dyes are at-r for example in "Journal of the Society of Dyers and Colourists", Volume 70, pages 69-71 (1954) and in Volume 74, page 389 (3958).

The main advantage of the ney-eration-appropriate hot plates is in the fact that they are photographically faithful images on their warmth surface can have, can be produced in a simple and inexpensive manner, and are excellent in terms of image sharpness Since the printing ink is embedded in the plastic coating, the image will also be worn if it is rubbed off not scuffed, so that there is increased wear resistance.

In the drawing shows

Fig. 1 is a perspective view of an embodiment cxner hot plate according to the innovation and

Fig. 2 is a broken away enlarged section of an arbitrary Cross-section through the heating surface of the heating plate.

The hot plate 4 shown in Figure 1 of the drawing has a grip strip 6 at both ends, between which

- 10 the heating element 5 with the printed heating surface is located.

Figure 2 of the drawing shows that the heating surface 1 has a plastic coating 2, which rests directly on the heating surface 1. Dyes 3 are in the plastic coating 2 in such a way stored that they border on its free surface, the case depicted only over a limited part of the Extend the thickness of the plastic coating, the plastic coating is free of dyes in its area directly adjacent to the heating surface 1.

Claims (4)

- A-L C I 1 Dr. Hans-HeinrichWilkath.t ·. ·· '- "·': D-l 6200 Wiesbaden ι 27.8.197 Dr. Dieter Weber Postfach 6145 DiOL-irhys. Klaus Seilten: <s! 06121) 372720 TdegramnudrtEc: WIIXPATENT PATENTANWÄLTE G 79 19 836.0 Kolloid Chemie GmbH protection claims 1.Heating plate, the heating surface of which has a plastic coating, characterized in that in the plastic coating (2) lying directly on the heating plate (1) the free surface of which is arranged adjacent in limited areas at least one dye (3). 2. Heat gap according to claim 1, characterized in that the plastic coating (2) consists of a cross-linked thermoset stands. 3. Heating plate according to claim 1 and 2, characterized in that that the dyes (3) are those which su- more blind. 4. Warming plate according to claim 1 T-> is 3, characterized in that that the dyes (3) are arranged in the plastic coating (2) in such a way that they adjoin its free surface only over part of the thickness of the plastic cover (2) extend. Postjdicdt: Frankfurt / Main 67O3-6C2 j * _t * PjnkiBresdn BjJik "^ G, Wiesbaden, Komo-# 276 807th