WO2012143334A1

WO2012143334A1 - Method for increasing wipe resistance and scratch resistance of plastic surfaces

Info

Publication number: WO2012143334A1
Application number: PCT/EP2012/056934
Authority: WO
Inventors: Heinrich Gruenwald; Rüdiger FOEST; Jan Schaefer
Original assignee: Leibniz-Institut für Plasmaforschung und Technologie e.V.; Neoplas Gmbh
Priority date: 2011-04-16
Filing date: 2012-04-16
Publication date: 2012-10-26
Also published as: DE102011007557B4; DE102011007557A1

Abstract

The invention relates to a method for increasing wipe resistance or scratch resistance of plastic surfaces, in which method first a silicon oxide layer and subsequently a friction-reducing substance are applied. In this connection, a silicon oxide layer is understood to mean a layer which essentially consists of SiO₂, however which can have deviations in the oxygen content and otherwise can contain a residual content of hydrocarbons. A typical formula is: SiO_1,8 to _2,4C_xH_y.

Description

Process for increasing the wipe resistance or scratch resistance of

Plastic surfaces

description

The invention relates to a method for increasing the wipe resistance or

Scratch resistance of plastic surfaces, in which first a silicon oxide layer and then a friction-reducing substance is applied. Under one

Silicon oxide layer is understood here as a layer consisting essentially of Si0 ₂ , but may have deviations in the oxygen content and otherwise may have a residual content of hydrocarbons. A typical formula is: Si0 _{1; 8 b} i _s

Plastics in addition to their technical function often still have a decorative. Thus, covers or frames of screens for complacent design can be made in high gloss. The same applies to other commodities, for example in the household sector. High-gloss decorative surfaces are also in high demand in the passenger car sector and can also be found here as plastics that are galvanically coated with metals. These surfaces can also be very sensitive to wiping or scratching.

However, stains such as fingerprints are particularly unpleasant on high-gloss surfaces, since they are particularly visible and destroy the optical effect achieved with the high gloss. It is therefore obvious to the user of such objects to rid the affected surface by wiping off such soiling. Many of the plastics used, especially polycarbonate (PC) or else

High-gloss paints are not resistant to this, but are also rubbed off with light rubbing or wiping with a cloth, even scratching them, which disturbs the original gloss of the surface in the sense of a uniform reflection pattern. With permanent rubbing stress, the surface can be rubbed off in such a way that it becomes dull there. Very disadvantageous are such abrasion and scratching on plastic surfaces with optical function, for example. Of lenses or transparent panes such as the covers of electronic displays. Not only the decorative, but also the technical function is at stake here. State of the art:

According to the prior art, this problem is often solved with scratch-resistant paints whose hardness more or less prevents the abrasion or scratching of the plastic surface. The cost of such coatings can be very high, considering the reject rates. Recently, significant scratch-protective effects have also been reported by quartz-like coatings of a few μπι (R.Hora, C. Wohlrab, "Plasma Polymerization: A New Technology for Functional Coatings on Plastic", SVC, 36 th Ann., Tech., Proc ), Pp. 51-55 and R. Beckmann, K.-D. Nauenburg, T. Naumann, U. Patz, G. Ickes, H. Hagedorn, J. Snyder, "New High-Rate Deposition Process for Scratch and Wipe-Resistant Coatings for Optical and Decorative Plastics, "SVC, 44th Ann., Tech. Conf, April 21-26 (2001) pp. 288-294.), Which are supported by plasma-assisted chemical

However, this process is cumbersome in that it requires the introduction of the parts to be coated into a closed vacuum chamber, which inhibits the flow of parts in the production process the devices for this considerably.

The method is now also with atmospheric plasma devices

Schäfer, R. Foest, A. Quade, A. Ohl, KD Weltmann, "Carbon-free SiOx films deposited on octamethylcyclotetrasiloxane (OMCTS) by An atmospheric pressure plasma jet (APPJ ), Eur. Phys., J. D 54, 211-217 (2009). Although the disturbance of the material flow and also the investment costs are lower, the productivity is often too high due to the long duration of producing layers of a few μm thickness low.

Also known is the adhesion-repellent effect of so-called

Nursing care substances which are used especially in the spectacle (EP 0963 797 A2) or sports optics (US 6542302) for the protection of coated surfaces. These substances are composed of more or less long, hydrophobic or even oleophobic molecular chains, which are equipped with chemical, functional groups, the

Bonding oxide surfaces firmly.

Under hydrophobic is understood here the property of a surface to repel water. This property shows, for example, that such a surface opposite to an attached drop of water forms a contact angle of about 90 ° and higher. Water and aqueous solutions or mixtures do not wet such a surface. At a contact angle of 100 ° and higher is often spoken of superhydrophobia or oleophobia. Such a surface is not wetted by hydrocarbons such as paraffins or mineral oils and also rejects skin oils and fats. However, it is also known that the mentioned care substances can not be used on plastics. Because on the latter they can not bind chemically and thus be wiped off, whereby the hydrophobing and the friction-reducing effect is not permanent.

Object of the invention:

The invention has the object to eliminate the disadvantages of the prior art.

Solution of the task

The object has been solved according to the features of the claims.

Surprisingly, it was found that the wiping and scratch resistance of

Plastic surfaces can increase decisively if they were coated by means of a plasma with a very thin oxide layer and then covered with a care substance. The surfaces of sensitive plastics or high-gloss coatings can be inventively with little effort from damage such as scratches,

To protect marks and abrasion. Under wiper marks are here understood scratches or indented grooves of small extent, which in areal

Frictional stress, for example with a wipe result.

The oxide layer can according to the invention with PECVD, sputtering

("Sputtering") or plasma-based vapor deposition on the protected

Plastic surfaces are produced. Silica is particularly suitable as oxides, but it is also possible to use titanium oxide or aluminum oxide and other oxides which can be applied as a layer by a plasma technique. As care textiles commercially available for this purpose materials such as "Optool DSX" (Daikin Industries Ltd.), "Duralon" or "Duralon Ultratec" (each of the Cotec GmbH, Karl Stein, Germany), "Everclean" (Umicore , Balzers, Liechtenstein) or "Satin" (by Satisloh, Baar, Switzerland).

The term "known easy care material" is used in the context of the invention, a commercially available easy care material consisting of an oligomer or

Polymer chain and at least one substituted silyl group with the general formula R Si X3- _X RH _X understood in the art, wherein R is an oligomer or

Polymer chain, Si is a silicon atom, X is a substituent from the group Cl, alkoxy or acetoxy and RH is a hydrogen atom or an alkyl radical.

The oligomer or polymer chain may be a substantially perfluorinated alkyl or alkyl ether chain or an unsubstituted alkyl or alkyl ether chain.

The substituted silyl group may preferably be a halosilane or an alkoxysilane or an acetoxy silane.

An additional advantage here is that the invention protected

Plastic surfaces are easy to care for. In this respect, they even hold oily or greasy soiling such as skin marks far less firm and dry

Wiping will provide less friction than the unprotected surface. As a result, the surfaces are much less damaged by cleaning procedures.

EXAMPLES

1. Atmospheric pressure plasma, 2.5 μm SiO 2 layer (comparative example)

10 nozzles according to J. Schaefer, R. Foest, A. Quade, A. Ohl, K.D. Weltmann, "Carbon-free SiOx films deposited from octamethylcyclotetrasiloxane (OMCTS) by An Atmospheric Pressure Plasma Jet (APPJ)", Eur. Phys. J. D 54, 211-217 (2009) were placed in line and a PC-plate from Makroion 2407 (Bayer) was hereby repeated

Covering coated with an approximately 2.5 μπι thick SiOx layer.

After a storage period of 7 days, the plate was loaded with a Abriebprüfgerät the Karl-Fischer Maschinenbau GmbH by moving back and forth a wool felt disc of 10 mm diameter with increasing weight load and increasing stroke rate. To 1000 strokes with a load of 8N showed the first scratches during visual inspection under daylight (D65) and standard light A. This was the case on an untreated plate after only 1000 strokes with IN load.

With the hardness test of Erichsen first injuries were observed with a spring preload of 6 N.

2. Atmospheric pressure plasma, 50 nm SiOx layer with subsequent vapor deposition of the care substance

A PC-plate from Makroion 2407 (Bayer) was coated as described in Example 1 with a 50 nm thick SiOx layer and 3 days later in a

Vacuum drying cabinet with a volume of 50 dm ³ with a care substance ETC1 from Surface Chemistry, Niddatal evaporated from the supplied, porous support material.

After a storage period of 7 days, the plate was tested with the Stroke tester as described in Example 1. After 1000 strokes with a load of 8 N, the first 3 scratches were visible during visual inspection under daylight (standard light D65) and standard light A.

3. Low-pressure PECVD with subsequent vapor deposition of the care substance in a vacuum

A test plate made of polycarbonate macroion 2407 from Bayer was coated in a cylindrical plasma reactor R300 (plasma electronic GmbH, Filderstadt, year of construction ca. 1990), volume about 10 dm ³ with a thin SiOx layer (plasma excitation with 50 W at 13, 56 MHz, process gases tetramethyldisiloxane and oxygen in the ratio of 1 to 5 at 50 Pa process pressure, duration: 5 min).

The sample plate was removed and then in a vacuum oven (wall temperature 70 ° C) with a thermal evaporator (temperature rising from 20 to 380 ° C) at a pressure of 5 mbar with the easy-care material ETC 1 of Surface Chemistry (Niddatal, Germany ) steamed. For this purpose, a porous filter body made of brass, soaked with 100 μΐ of the care substance ETC1, was placed in the thermal evaporator

After a storage period of 7 days, the plate with a Abriebprüfgerät Karl-Fischer Maschinenbau GmbH by moving herzogen and a Wollfilzscheibe of 10 mm diameter loaded with increasing weight load and increasing number of strokes. After 1000 strokes with a load of 8N, the first scratches were visible under visual examination under daylight (D65).

In contrast, untreated panels of the same material withstood just 1000 strokes with 1 N weight load before first scratches became visible under the same conditions.

Another test was carried out using a hardness test of the company Erichsen. Here, a test probe with a ball diameter of 1 mm was passed once in a line across the surface. The load on the surface is set by the bias of the test probe with a spring between 1 and 20 N. The scratches or impressions of the surface were tested under the illumination conditions described above. A macroion 2407 PC plate treated according to the present invention showed traces at a spring bias of x 5 N while an untreated plate at 3 N had first traces.

4. Application of the SiO x layer with cathode sputtering with subsequent vapor deposition of the easy-care substance in a vacuum

5. Atmosphere plasma and subsequent high-vacuum vaporization in Syrus

Another PC board from Makroion 2407 was coated with the Atmosphärenplasmagerät as in Example 1, the layer thickness, however, set to about 50 nm. Subsequently, as in Example 1, the care substance ETC 1 of Surface Chemistry was vapor-deposited. In the stroke test, the first injuries were found after 1000 strokes with 4 or elsewhere with 8 N load.

The test with the hardness test according to Erichsen revealed first injuries from a spring preload of 4 or 5 N.

6. Atmospheric plasma / vaporization

7. Possibly. Plasma-assisted steaming and easy-care steaming in Syrus.

Claims

claims:

1. A method for increasing the wipe resistance or scratch resistance of

Plastic surfaces, characterized by the following steps

the plastic surface to be protected is coated by means of a plasma with a thin, between 2 and 100 nm thick, consisting essentially of an oxide layer and

- At least one per se known easy care material is applied to this layer.

2. The method according to claim 1, characterized in that an atmospheric pressure plasma or vacuum plasma is used.

3. The method according to claim 1 or 2, characterized in that the oxide layer with PECVD, cathode sputtering ("sputtering") or plasma-assisted vapor deposition is brought to the plastic surface.

4. The method according to any one of claims 1 to 3, characterized in that it is the oxide to silica, titania or alumina.

5. The method according to any one of claims 1 to 3, characterized in that the application of the easy-care material takes place by means of vapor deposition.

6. The method according to any one of claims 1 to 5, wherein the plastic surface

was metallized by electroplating.

7. Wipe- and scratch-resistant plastic surfaces, obtainable by applying a 2 to 100 nm thick oxide layer on these plastic surfaces by means of a plasma and then applying a known easy-care material on these plastic surfaces.