EP1611228B1 - Method for surface-metallizing wax objects, especially for silver-plating candles to give them a bright de luxe shine - Google Patents

Abstract

The invention relates to a method for surface-metallizing wax objects, especially for silver-plating candles to give them a bright de luxe shine. The inventive method comprises the steps of applying a base coat to the surface of the object to be finished, drying the base coat, treating the surface of the base coat layer with a presensitizing solution, applying a solution containing a metallization agent to the presensitized surface of the base coat layer while depositing a metallization layer, drying the metallization layer so produced, applying a transparent coating varnish and drying the coating varnish layer so produced.

Description

The invention relates to a process for the surface metallization of wax articles and in particular for the mirror-like silvering of candles.

From EP 0 308 921 B1 a method for the production of decorative candles with a metallic surface decor is known in which a wax candle is painted with an alcohol and then metallized under vacuum. In order to produce the most uniform and durable metallization, an aging process of at least 60 hours should be carried out between painting and metallizing. This means that in the production process of the candles a time-consuming storage step is provided, for which moreover the corresponding space must be available. Furthermore, in the known method of disadvantage that only laborious to be operated and limited in production throughput Vakuumbedampfungsanlage is used. This makes the manufacture of such decorative candles extremely expensive.

Based on the described problems of the prior art, the present invention seeks to provide a method for surface metallization of wax articles, in particular for mirror-silvering of candles, which is feasible with a comparable decor quality more rational and with significantly less equipment.

• Auftragen eines Grundlackes auf die zu veredelnde Oberfläche des Artikels,
• Trocknen des Grundlackes,
• Behandeln der Oberfläche der Grundlackschicht mit einer Vorsensibilisierungslösung,
• Auftragen einer ein Metallisierungsmittel enthaltenden Lösung auf die vorsensibilisierte Oberfläche der Grundlackschicht unter Abscheidung einer Metallisierungsschicht,
• Abtrocknen der gebildeten Metallisierungsschicht,
• Auftragen eines transparenten Decklackes und
• Trocknen der gebildeten Decklackschicht.

This object is achieved by the method steps indicated in the characterizing part of claim 1 as follows:

• Applying a base coat to the surface of the article to be finished,
• Drying the basecoat,
• Treating the surface of the base coat layer with a presensitization solution,
• Applying a metallization-containing solution to the presensitized surface of the base coat layer to deposit a metallization layer,
• Drying the formed metallization layer,
• Apply a transparent topcoat and
• Drying of the formed topcoat layer.

By applying a base coat on the surface of the wax article to be refined, all types of, for example, unpainted candles can be surface-finished. The base coat prepares the substrate for the metallization and in particular allows wetting. It also ensures good adhesion to the article surface.

The presensitization solution is used to ensure wetting of the substrate surface for the further wet chemical preparation steps and the subsequent metallization process. This improves the adhesion of the metallization layer to the substrate. This can be further improved by the preferred use of multiple presensitization solutions.

The actual metallization of the article surface then takes place by the application of a metallization solution which deposits a metallization layer. This is preferably done by spraying a two-component, a reducing solution and a metallizing solution made composite spray solution. The components are preferably mixed in the nozzle head of a spraying device directly during the spraying, the precipitation of the metallizing particles taking place during the spraying process. A thin, highly reflective layer is formed. The reduction solution is based on modified saccharides, in the case of silver plating the metallization solutions are those which mainly contain silver diamine nitrate and ammonium hydroxide and sodium hydroxide. In small amounts of conventional stabilizing additives are added.

The topcoat layer applied to the metallization layer protects the metallization against corrosion, in particular yellowing or blackening. It is also possible to produce a coloring of the mirror decoration or a glossy or matt design of the surface structure via the transparent topcoat layer. This allows the design to achieve a variety of design options for surface-metallized wax articles.

The topcoat is preferably composed of one or more binder dispersions based on polyurethane, polyester and / or polyacrylate. Furthermore, defoaming agents may be added to the topcoat as well as the basecoat to ensure complete bursting of any air bubbles resulting from the immersion of the wax articles into corresponding paint baths during the course of the finish of the article.

Further features, details and advantages of the method according to the invention will become apparent from the following

Embodiment:

It describes a refining process for all types of unpainted candles, which are provided with a mirror-finished silver layer.

In a first process step, a base coat of the following composition is applied by immersing the candles: component Type Quantity g ^-1 Polyester polyol CEL softener 1.93 L2 resin binder 15.83 Eastman CAB 553-0.4 binder 5.37 1-methoxy-2 solvent 7.37 Ethanol 99% solvent 67.78 acetone solvent 0.48 Efka - 2038 defoamers 0.50 Addid 131 Gradient and wetting agent 0.74 Σ basecoat 100.00

The solvent content of this basecoat is 76.48%, its solids content 23.52%. It is set to a viscosity of 15 s in the 4 mm DIN cup at 20 ° C. The fullness and luster of this base coat are decisive for the quality of the subsequent silvering and its brilliance.

In the case of the dip painting process carried out by hand or by machine, after the lacquer has drained off, the residual drop remaining at the base of the candle is dabbed off. Thereafter, a complete drying of the paint film is also carried out at the bottom of the candle. The through-drying can take place, for example, at room temperature in a suspended state over a period of at least 12 hours, that is to say overnight, for example.

Thereafter, the application of the silver plating is carried out in several steps. Thus, the surface of the through-dried base coat layer is treated with two Vorsensibilisierungslösungen. The first presensitization solution contains mainly modified saccharides and small amounts of regulatory additives present in an acidic, concentrated mixture. These presensitization solutions are available from Spraylat Corp. NT. Vernon, NY, USA and Aachen, Germany, under the name TL-30 and sold by the applicant under the item number 1275 1. This watery, clear, yellow-brown liquid is completely soluble in water and is acidic.

The first presensitization solution should be used in a 1: 9 dilution with deionized water.

The basecoated candles should be dipped into the presensitization solution and then rinsed with deionized water.

Subsequently, a second presensitization solution containing mainly tin-halogen compounds and hydrochloric acid is applied. It is an aqueous, clear, colorless to slightly yellowish liquid that smells pungent and is completely soluble in water. This second presensitization solution serves to optimize the adhesion of the silver layer to the base coat layer.

The second presensitization solution is used at a high dilution, for example one liter of deionized water is added to one milliliter of this solution.

The Vorsensibilisierungslösung 2 is sold by the company Spraylat under the name "SCS" or by the applicant under the number 1275 2.

For the subsequent silver plating, a wet-chemical silver plating process is used. Starting solutions are an acidic reduction solution containing mainly modified saccharides and small amounts of additives, and a silver solution consisting of two separate base solutions.

The reducing solution is sold by the company Spraylat under the name "BKR-5" or by the applicant under the number 1275 3. It has a pH (at 22 ° C) of about 0.5 to 1.0 and is a watery, clear, slightly pinkish liquid. The first base solution, which actually contains the silver, contains silver diamine nitrate, ammonium hydroxide and small amounts of stabilizing additives. It is an aqueous, clear, blue liquid that smells strongly ammoniacal. It is completely soluble in water. Its pH is about 11 to 12 at 22 ° C.

This base solution is mixed in equal parts by volume with the second base solution containing sodium hydroxide, ammonium hydroxide and small amounts of stabilizing additives. It is an aqueous, clear, slightly greenish liquid whose odor is also ammoniacal. Its pH is about 13 at 22 ° C. This second base solution is essentially a reaction accelerator solution, whereby the reaction rate can be increased by increased addition.

The two silver solutions are sold under the names "BKA-5" and "BKS-5" by the company Spraylat or under the numbers 1275 4 and 1275 5 by the applicant. The reducing solution, on the one hand, and the silver solution consisting of the two aforementioned base solutions, on the other hand, are each filled into separate pressure vessels of a spraying device in whose nozzle head the two solutions are mixed immediately before spraying. The precipitation of the silver particles takes place during the spray path from the nozzle head to the surface to be mirrored. The injection period is about 10 to 15 seconds until a fully silvered surface is achieved by forming a continuous silver layer. The spray pressure is about 2 bar, with the mixing nozzle head has a 1-mm nozzle.

After immersing the primed candles in the Vorsensibilisierungslösungen and after spraying the metallizing solution is rinsed in each case with deionized water by spraying. This water rinse is carried out with a cup spray gun or a spray gun with pressure vessel, with a nozzle size of 1.8 mm is used.

After applying the metallization layer, the candles are dried for at least four hours, but the painting process should be completed after 24 hours.

For this purpose, a transparent topcoat is applied, which serves to protect the silvering of corrosion, ie yellowing or blackening. The painting is done again in the immersion process, the final drying takes place under ambient conditions or can be abbreviated by heat support.

Through the topcoat layer, the finish of the candle can still be varied to the effect that the mirror layer is colored. Furthermore, a matting can take place.

The following are examples of compositions of various topcoats:
- Top coat glossy component FK ·% ^-1 Type Quantity g ^-1 Halwedrol OX 87/40 W 40.0 binder dispersion 773.00 (PURE) Joncryl95 30.0 binder dispersion 200.00 (PA) Tafigel PUR 40 -Lsg. 20.0 thickener 5.00 Surfynol DF-66 49.0 defoamers 5.40 Wasserdeion. 0.0 water 5.40 butylglycol 0.0 solvent 3.30 Surfynol 2502 0.0 wetting agent 1.10 Byk 347 82.0 wetting agent 1.50 butylglycol 0.0 solvent 4.50 Fisantrol 3010 50.0 Additive for improvement 2.00 the surface smoothness □ 39,80 Hydro paint glossy 1,001.20
- Topcoat matt (1st variant) component FK ·% ^-1 Type Quantity g ^-1 Halwedrol TN 6880-2 / 40 40.0 binder dispersion 783.40 W (PUR, polyester) Tafigel PUR 40 -Lsg. 20.0 thickener 22.00 Deuterone MK 100.0 Mattierungskunststoff 35,00 Syloid ED-30 100.0 matting agent 60,00 water 0.0 water 92,80 Byk 027 100.0 defoamers 6.80 Σ 44.31 Hydro paint mat 1 1,000.00
- Topcoat matt (2nd variant) component FK ·% ^-1 Type Quantity g ^-1 Halwedrol OX 87/40 W 40.0 binder dispersion 673.00 (PURE) Joncryl 95 30.0 binder dispersion 173.00 (PA) Deuterone MK 100.0 Mattierungskunststoff 50,00 Syloid ED-30 100.0 matting agent 38,00 water 0.0 water 51.00 Latekoll D 32% 32.0 thickener 10.00 Byk 027 100.0 defoamers 5.00 Σ 43.52 Hydro paint matt 2 1,000.00

The viscosities of the above-mentioned topcoats are adjusted to 27 seconds in a 4 mm DIN cup at 20 ° C. Each coloration is carried out by adding 10% solutions of the respective dyes in 1-Metoxipropanol-2. Subsequently, the viscosity is adjusted to 13 seconds in the 4 mm DIN cup by adding deionized water.

As is apparent from the above compositions, the topcoat is composed of one or more binder dispersions in a mixture based on polyurethane, polyester and / or polyacrylate. The binders show little or no yellowing when stored under standard conditions.

A matted topcoat additionally contains one or more matting agents, which can be composed of different classes of compounds.

Due to the thickener, the solids content of the topcoat can be lowered. Suitable wetting agents ensure adequate wetting of the silver layer by the topcoat.

The envisaged defoaming agents accomplish a complete bursting of all air bubbles generated by the immersion of the silvered candles in the topcoat during the course of the paint from the candle.

By the topcoat, the access of oxygen to the silver layer is largely prevented, which brings the desired corrosion protection with it. Thus, a loss of gloss (the so-called "tarnishing") of the silver layer is avoided.

The dried paint film also ensures sufficient burning of the candle, d. H. he does not tear when burning the candle, it does not cause pollution of the fire dish and is not flammable itself. The dried paint film is further characterized by a sufficient under normal storage conditions (below 35 ° C and 80 ° C relative humidity) sufficient water resistance, d. H. it does not detach itself and can not be removed without significant shearing forces parallel to the paint surface.

Claims (14)

1. Method for surface-metallising wax objects, especially for silver-plating candles to give them a bright de luxe shine, characterised by the following method steps:

   - applying a primer to the surface of the object to be finished,

   - drying the primer,

   - treating the surface of the primer coat with a presensitising solution,

   - applying a solution containing a metallisation agent to the presensitised surface of the primer coat, a metallisation coat being deposited,

   - drying off the metallisation coat which is formed,

   - applying a transparent top paint and

   - drying the top coat which is formed.
2. Method according to claim 1, characterised in that the primer is applied using the dipping method.
3. Method according to claim 2, characterised in that the primer is based on solvents, binders and additives, in particular plasticisers, flow promoters, wetting agents and defoaming agents.
4. Method according to claim 2 or 3, characterised in that the primer is dried for at least 12 hours, preferably at room temperature, until the primer coat has dried completely.
5. Method according to any one of the preceding claims, characterised in that for presensitising the surface of the primer coat, the object is dipped into at least one presensitising solution.
6. Method according to claim 5, characterised in that a first presensitising solution containing mainly modified saccharides and a second presensitising solution based on hydrochloric acid and tin/halogen compounds are used.
7. Method according to any one of the preceding claims, characterised in that the metallisation layer is applied by spraying a two-component spray solution composed of a reducing solution and a metallisation solution.
8. Method according to claim 7, characterised in that the reducing and metallisation solutions are mixed, immediately prior to spraying, in the nozzle head of a spray device.
9. Method for silver-plating wax objects according to claim 7 or 8, characterised in that the reducing solution contains mainly modified saccharides.
10. Method for silver-plating wax objects according to any one of claims 7 to 9, characterised in that the metallisation solution contains mainly silver diamine nitrate and ammonium hydroxide.
11. Method according to claim 10, characterised in that an accelerator solution containing mainly ammonium hydroxide and sodium hydroxide is added to the metallisation solution.
12. Method according to any one of the preceding claims, characterised in that the top coat is applied by dipping the object into a one-component or multicomponent binder dispersion based on polyurethane, polyester and/or polyacrylate.
13. Method according to claim 12, characterised in that the binder dispersion contains a defoaming agent.
14. Method according to claim 12 or 13, characterised in that flatting agents and/or dyes are added to the binder dispersion.