DE102006040200A1 - Process for coating a plastic part - Google Patents

Abstract

A method for coating a plastic part (10) with lacquer is proposed. In this method, in a flooding step, a surface of the plastic part (10) to be coated is provided with lacquer by impingement of an inflow region (A) of the surface to be coated and by drainage of the lacquer via a drainage region (B). In accordance with the invention, before the flooding step is carried out, the flooding area (A) is sprayed with paint in a spraying step so that a paint coating consisting of sprayed-on and flooded paint is formed in the flooding area, and in the drainage area (B). the surface to be coated a paint coating is formed, which consists only of flooded paint.

Description

The The invention relates to a device for coating a plastic part with a paint according to the preamble of patent claim 1.

flooding for forming coatings on plastic parts are known from Practice known and are usually carried out in such a way that a surface to be coated the plastic part in a so-called flooding area with paint or the like is applied. Then distributed in the Influx applied paint by gravity due to the remaining area to be coated, which is also referred to as Abflutbereich.

The coating formed in a flooding process has a wedge-shaped layer thickness distribution, wherein in the trough area a lower layer thickness than is present in the discharge area. For example, if the coated component As a body part of a motor vehicle is set, is layer thickness formed in the flooding region may not be sufficient, to protect the component sufficiently against weathering and other environmental influences.

Of Furthermore, it is known in the field of motor vehicle bodies, Use polycarbonate components. But polycarbonate has one low weather and media resistance and high scratch sensitivity and must therefore be provided with a coating. A after a conventional Flooding applied coating protects the plastic substrate made of polycarbonate but may not be sufficient.

A flood coating method for forming an abrasion and strength-resistant coating on a plastic substrate is also known from DE 10 2004 027 842 A1 known. This plastic substrate may be formed of polycarbonate.

Of Furthermore, it is known that abrasion and scratch resistant coatings after a spray process to apply to a plastic part to be coated. In the spraying process A paint to be applied in atomised form on the surface of the Applied plastic part. But this forms an orange peel-like surface structure so that this method is not suitable for large-area optical components or Glazing components of a motor vehicle is suitable.

Also It is known to apply coatings by a dipping method to apply plastic part to be coated. Here is the to be coated plastic part immersed in a dip, wherein the coating material or the paint when pulling out of the plastic part the dipping bath from above, i. from a header, down, i. over one footer the area to be coated expires.

Of the Invention is based on the object, a method for coating to provide a plastic part, wherein the produced coating high optical claims enough and the coated plastic substrate increased wear resistance is taught.

These Task is according to the invention by the Method solved with the features of claim 1.

Of the The core of the invention is therefore one of a flood process and a spraying process to use a combined method in which a to be coated Plastic part initially only in a critical area, which in the flooding step the tidal area shown, sprayed with paint and then a substantially full-surface Coating of the plastic part is done by a flood process. In the spraying step Therefore, a partial pre-coating of the plastic part takes place. Through the full-surface Flooding of the component, a visually pleasing component quality is achieved. By the partial spraying the plastic part with lacquer will be a partial layer thickness increase in the Created flooding area. In contrast to a so-called double flooding there is no increase the layer thickness in a so-called drainage area, d. H. the area of the plastic part, over the the applied paint runs off when flooding.

Basically the method of the invention for a variety of applications suitable in which a plastic workpiece with a paint or a Be coating to be provided. In particular, but that is suitable Method according to the invention for coating an example flat Plastic part with an abrasion and Scratch-resistant layer, leaving the plastic part as the body part of a Motor vehicle can be used. For example, that forms Plastic part made of polycarbonate roof of a motor vehicle. The plastic part can also be a cover element of a motor vehicle roof opening system, like a sunroof, be. It is also conceivable that the plastic part a diffuser of a vehicle headlight, a body cover strip or the like forms.

Of the Term floods is in its present context in its widest Meaning and also includes conventionally referred to as casting Application processes in which paint from a vessel in the trough area over the to be coated plastic part is poured.

at an expedient embodiment of the Method according to the invention is between the spraying step and the flooding step carried out a Lackabdunstschritt and in the flooding step, a dissolution occurs in the spraying step applied lacquer layer, so that one in the spraying step and the Lackabdunstschritt resulting surface structure is dissolved. Due to the flooding of the surface to be coated is therefore optionally optical requirements insufficient surface structure in the spraying step dissolved layer dissolved. A shine through of a so-called orange peel-like structure can thus be excluded.

Of the in the method according to the invention used lacquer can on Polysiloxane be formed paint, in its liquid state a sol forms. A Derar tiger, transparent executed paint is particularly suitable as an abrasion and scratch resistant coating a transparent polycarbonate component.

The Orientation of the plastic component during the coating with Lacquer is essentially dependent of its geometry. So can a substantially planar component while the coating have a vertical orientation. A curved component on the other hand is expediently inclined in a suitable for applying the coating paint shop brought in.

The Duration of the spraying step and the duration of the flooding step are also essentially dependent on the geometry and dimensions of the component, but also of the Properties of the paint used.

In usually the plastic part after its coating, d. H. after execution of the flooding step, subjected to a varnish curing step. at Using a conventional For this purpose, polysiloxane-based lacquers, for example, are the coated component a temperature of about 100 ° C up to 150 ° C exposed. It can but also polysiloxane paint systems are used which are exposed to ultraviolet Cure radiation. The coated component is then subjected to no heat treatment, but exposed only to ultraviolet radiation.

Of the Order of the coating on the plastic part is expedient in one Temperature range between 20 ° C and 40 ° C, d. H. essentially at room temperature, but is also dependent on the each used paint system.

The The invention also has a method of coating a plastic part with paint on the subject, in which in a dipping step to be coated area the plastic part is provided with paint. A head area of the Plastic part is before execution of the dipping step in a spraying step sprayed with varnish, so that a paint coating is formed in the head area, the sprayed out and by dipping applied paint, and in a foot area the area to be coated a paint coating is formed, which is applied only by dipping Paint exists. The head area of the surface to be coated Plastic part represents the area that in the dipping step is up and therefore pulled out of the dipping bath first. The foot area represents the remaining area to be coated and thus a drainage area lying down and over the paint runs off. In this drainage area is the layer thickness of the applied paint usually larger than in the head area, which is due to the upstream spraying of the Head area can be compensated with paint.

Further Advantages and advantageous embodiments of the subject after the Invention are the description, the drawings and the claims removed.

One embodiment of the method according to the invention will be described below with reference to FIG simplified drawing closer explained. It shows

1 a section through a sheet-like polycarbonate plastic part before its coating;

2 the polycarbonate plastic part when performing a spraying step;

3 the polycarbonate plastic part when performing a flooding step; and

4 the plastic part after execution of a Lackeinbrennschrittes.

In the drawing, a flat or plate-shaped plastic part 10 shown, which consists of transparent polycarbonate and is produced by an injection-compression molding process. The plastic part 10 forms a roof of a motor vehicle and is for producing a scratch-resistant and weather-resistant outer surface with a coating 12 to provide, which in particular in 4 is shown.

To produce the coating, the in 1 in the raw state shown polycarbonate plastic part 10 introduced in vertical alignment in a paint shop, not shown. There is at a first workstation, which is associated with a so-called spraying step, on the surface to be coated of the plastic part 10 in a region A via nozzles 13 more transparent, on butt Lysiloxane-based paint to form a spray layer 14 sprayed on ( 2 ). The area A, which is thus charged with atomized paint, provides a so-called flood area in a 3 Flood step shown in more detail.

After performing the in 2 spraying step is left in the form of the spray layer 14 briefly evaporate applied paint. At the spy layer 14 Forms a surface structure that is orange peel-like.

Then the plastic part 10 that with the spray layer 14 is provided in the 3 shown flooding step, in which the plastic part 10 in another work station in its tidal area A by means of an applicator 15 flooded over a large area with paint that corresponds to the paint that was previously sprayed in the flooding area A. The flooded in the trough area A paint passes over the vertically oriented plastic part 10 on the surface to be coated down over a region B of the plastic part, which represents a so-called discharge area. It thus forms on the plastic part 10 the entire surface here as a flood layer 16 designated paint layer with a wedge-shaped layer thickness distribution, which is the spray layer 14 superimposed in the flooding area A.

Subsequently, the provided with paint polycarbonate plastic part 10 heated to about 100 ° C to 150 ° C and thus fed to a Lackaushärtungsschritt.

The result is the coating 12 the plastic part 10 which satisfies, over its entire extent, a wear requirement placed in the region of a vehicle roof and is made sufficiently thick, even in the area of the tread A.

By the erfindungemäße combination a spraying process and a flood process can be a coating with a defined Layer thickness structure getting produced. In particular, in the tidal area A a layer thickness be achieved, which in the body exterior of a motor vehicle meets the requirements.

10

Plastic part

12

coating

13

jet

14

spray layer

15

applicator

16

flood layer

A

flow area

B

Abflutbereich

Claims (7)

Process for coating a plastic part ( 10 ) with paint, in which process in a flooding step to be coated surface of the plastic part ( 10 ) is provided with paint by impingement of an inflow region (A) of the surface to be coated and by drainage of the lacquer over a discharge region (B), characterized in that the inflow region (A) is sprayed with lacquer in a spraying step prior to the flooding step, then a varnish coating consisting of sprayed-on and flooded lacquer is formed in the tread area, and in the tapping area (B) of the surface to be coated a lacquer coating is formed which consists only of flooded lacquer. Process for coating a plastic part with Lack, in which process in a dipping step to be coated area the plastic part is provided with lacquer, characterized that a head area of the surface to be coated before execution of the Immersion step in a spray step sprayed with lacquer so that a paint coating is formed in the head area, the sprayed out and by dipping applied paint, and in a foot of the to be coated surface a paint coating is formed, which is applied only by dipping Paint exists. Method according to claim 1 or 2, characterized that between the spraying step and the flooding or dipping step takes place a Abdunstschritt and in the Flooding or dipping step the paint layer applied during the spraying step is dissolved, so one at the spraying step resulting surface structure disbanded becomes. Method according to one of claims 1 to 3, characterized the plastic part is a polycarbonate glazing component of a Motor vehicle is. Method according to one of claims 1 to 4, characterized that the polysiloxane-based paint is produced. Method according to one of claims 1 to 5, characterized in that the plastic part ( 10 ) is subjected to a paint curing step after being coated with the paint. Method according to one of claims 1 to 6, characterized that the plastic part at its coating a temperature between 20 ° C and 40 ° C has.