DE4433626A1 - Multilayer antistatic polyolefin-based plastics film - Google Patents

Abstract

Electrically conductive multilayer polyolefin based plastics film in which the conductive additive is incorporated as a filler into the plastic of an outer layer in reticular fashion to render the outer layer penetrably conductive. Pref. conductive additive is carbon black and/or antistatics and/or conductive inorganic pigments. Suitable antistatic is a nonionic cpd. in the form of uncharged surface active molecules. The active layer contains 2-40 (pref. 20-30) wt.% carbon black and 0-5 wt.% antistatics w.r.t. 100 wt.% of the plastic. The concn. of conductive additive incorporated is adjusted to give a conductivity of \- 10<-11> 1/ohm (Siemens), esp. 10<-5>-10<-9> 1/ohm (Siemens).

Description

The invention relates to an electrically conductive multi-layer plastic film on polyo lefine basis, the plastic conductive additives having.

Such multilayer films, in the form of rolls, Elbows, half tubes and especially hoods for use dung as covers for motor vehicles, for example around Lac to carry out cations are already known. The ther mix and electrical properties of these foils however, are not satisfactory. In particular is the conductivity of the known films is uneven formed over the film, creating a uniform Discharge of electrical charges is not ensured.

The invention therefore proposes that the conductive Additives in the plastic as an outer layer Fillers are embedded in a network, such that the outer layer consistently conductive is. Such storage of electrically conductive gene additives ensures that over this layer electrical charges can be discharged evenly nen. In particular, the network-like Storage one evenly over the entire slide distributed surface conductivity ensured.

Suitable, storable in the polyolefin plastic Ge conductive additives are especially carbon black and / or Antistatic and / or electrically conductive inorganic Pigments. It was surprisingly found that the Combination of soot parts in the plastic with one Antistatic to increase the lead significantly  ability leads without the mechanical properties the plastic film are too badly affected.

The invention advantageously enables the conductivity of the film to be stepped down to a conductivity of up to 10 ^-11 1 / ohm (Siemens), but preferably to a conductivity of 10 ^-5 to 10 ^-9, by controlling the concentration of the conductive additive 1 / Ohm (Siemens).

It is envisaged that the proportion of the antistatic 0 to 5 weight percent, or that the proportion of carbon black between 0 and 40 percent by weight, preferably around 20 up to 25 percent by weight based on 100 percent by weight percent of the plastic. Preferred is further a combination of carbon black with antistatic agents, the Soot content about 25 percent by weight including about 2 Weight percent antistatic based on 100 weight percent percent of the plastic.

There is also an outer layer in the plastic Color pigment stored as a filler, which on the one hand the conductive color due to different colors Layer can be recognized immediately and the other one preferred white color pigment that is temperature resistant speed of a film according to the invention of 120 degrees Celsius increases for at least 5 minutes.

In particular, special soot concentrates are used the aftertreated, conductive carbon black parts used. These soot concentrates are in the form of a soot master batch, as a carbon black paste, as a carbon black dispersion or the like in the Plastic granules mixed through an extruder puts. In addition or as an alternative, An tistatics, such as fatty acid esters, fatty acid amine and / or  -amides, glycerol monostearate, -oleate etc. are added. The soot concentration required for this is dependent of the carbon blacks used, the matrix, the processing method and the requirements. When adding the Soot and / or the antistatic agents used is in usually a soot content of 3 to 65% is required. Preferably a soot content of 15 to 30%, further before preferably from 20 to 25%. The method of familiarization and the distribution of soot in the matrix play a role an essential role. Antistatic agents can be used individually initially cation-active compounds with mostly a long alkyl radical containing cation (a quaternary res ammonium, phosphonium or sulphonium salt) for Deployed, with the quaternary group also in a ring system (e.g. imidazole) can occur.

The antistatic agents can also contain anion-active compounds be, mostly an alkyl sulfonate, sulfate or -phosphate, a dithiocarbamate or carboxylate.

Furthermore, the antistatic can be non-ionic endings. These are uncharged, surfactant molecules of much less Polarity as ionogenic compounds, such as. Polyethy lenglycol esters or ethers, fatty acid esters or ethano lamids, homo- or diglycerides or ethoxylated fatty amines no

External antistatic agents can also be used the. Here, the antistatic agents are not in the art contain granulate, but will only be added later Lich applied to the finished film. E.g. it is are hygroscopic substances such as glycerin, Polyols or polyglycols which have the characteristic of the interface activity is missing.  

While it is already known that the same Soot concentration different values with regard to the festge electrical properties of such a film what, for example, on unforeseeable Wed. or demixing operations is the soot concentration in a outer film is also much more predictable. It a good dispersion of the soot is foreseeable reached.

In addition or as an alternative to the soot parts mentioned and antistatic agents can also be conductive, inorganic Pigments (mixed pigments) may be contained in the film. The amount of carbon black added is based on the weight the film, at 2 to 40%, preferably in the range of 20 to 30, more preferably 25%.

The plastic films can be individually from the art substances PE, PP, PB and their recyclates exist. she are free from migrating lubricants.

It is further preferred that at least one layer of PP consists.

In addition, it is preferred that an inner layer the film Corona is untreated or coated with adhesive is. This is intended to ensure better liability on a Motor vehicle body can be reached about.

The adhesive coating can be made on a rubber basis or as a solvent-based acrylic adhesive or water based.

The total thickness of the film is at least 10 µm and maximum about 50 µm.  

The film can be made by cast or blown film be generated.

The invention will be further explained with the aid of the drawing tert, the

Fig. 1 to 4 increases the microstructure of plastics with embedded network-like conductive additives show

Fig. 5 shows a schematic section through a film according to the invention and

FIG. 6 to illustrate the inventive film is used.

In Figs. 1 to 4 four scanning electron micrographs are microscope photographs, which correspond to approximately one hundred thousand times magnification is shown. There, Figs. 1 and 2 SEM micrographs of an etched press plate PP, Figs. 3 and 4 SEM micrographs of a angeätz th PP-plate injection molding, each having a conductive Rußcompound. There are soot particles (black) and plastic parts (mainly white) to be distinguished. The embedding of the soot in the spaces / valleys of the plastic parts explains the network-like structure shown.

As shown in FIG. 5, the film 1 can have three layers, a first layer 2 having a thickness 3 of 7 μm, a second layer 4 having a thickness 5 of 11 μm and a third layer 6 having a thickness 7 of 7 μm . The layers 2, 4 and 6 are co-extruded or laminated onto one another. The first layer 2 is formed by the incorporation of electrically conductive additives 8 and is particularly conductive. The additives 8 are added as fillers in the plastic 9 of the first layer 2 to one another in a network-like manner, as a result of which the good conductivity according to the invention is achieved. It is also preferred that the film 1 by embedding color pigments 10 in the plastic 11 z. B. the third layer 6 is colored so that the front 12 and back 13 can be distinguished. It is essential that the conductive first layer 2 not on z. B. a body 14 rests, but is in the position of use outside, see. Fig. 6. It is shown how the body 14 of a motor vehicle 15 can be covered by means of the film 1 according to the invention, for B. to allow painting of a fender 16 . The film 1 can be used as covers 17 for covering z. B. the tire 18 may be formed or as a sheet or cut from a roll to cover individual vehicle parts such as bumpers, lamps, etc. of the motor vehicle 15 . For such a use in particular, the back 13 of the film 1 is coated with an adhesive 19 , cf. Fig. 5, whereby a self-adhesion of the film on the addressed parts of the body 14 is achieved.

The in the above description, the drawing and Features of the invention disclosed in the claims can both individually and in any combination for the realization of the invention may be of importance. All the features disclosed are essential to the invention. In the disclosure of the application is hereby also the Disclosure content of the associated / attached priori full documents (copy of the pre-registration) included.

Claims (15)

1. Electrically conductive, consisting of several layers existing polyolefin-based plastic film, the plastic having conductive additives, characterized in that the conductive additives ( 8 ) in the plastic ( 9 ) of an outer layer ( 2 ) as fillers are network-like stored are such that the outer layer ( 2 ) is continuously conductive. 2. Plastic film according to claim 1 or in particular afterwards, characterized in that the conductive Additive carbon blacks and / or antistatic agents and / or conductive are inorganic pigments. 3. Plastic film according to one or more of claims 1 to 2 or in particular according thereto, characterized in that by controlling the concentration of the conductive additive ( 8 ), the conductivity to at least 10 ^-11 1 / ohm (Siemens), preferably to 10 ^-5 to 10 ^-9 1 / Ohm (Siemens) is set. 4. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the antistatic is a non-ionic Compound in the form of uncharged surfactant Is molecules. 5. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the proportion of the antistatic 0 to 5 Weight percent, based on 100 weight percent of Plastic.   6. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the proportion of soot is between 0 and 40 Weight percent, preferably at about 20 to 20 weight percent, based on 100 percent by weight of the plastic fes is. 7. Plastic film according to one or more of the previous existing claims or in particular characterized thereby records that the soot content at about 25 weight percent including about 2 weight percent antistatic, bezo to 100 percent by weight of the plastic. 8. Plastic film according to one or more of the preceding claims or in particular characterized in that in the plastic ( 11 ) of an outer layer ( 6 ) a color pigment ( 10 ), preferably a white color pigment, is incorporated as a filler. 9. Plastic film according to one or more of the preceding claims or in particular according thereto, characterized in that the conductive layer ( 2 ) against the outer layer ( 6 ) is corona-untreated and / or coated with an adhesive ( 19 ). 10. Conductive multilayer plastic film on polyo lefin basis, the plastic has soot parts, characterized in that in addition to the soot in the Plastic contains an antistatic. 11. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the antistatic is a cation active Connection is.   12. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the antistatic is an anionic Connection is. 13. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the antistatic is a non-ionic Compound in the form of uncharged surfactant Is molecules. 14. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the antistatic as an external An tistatic is applied to the film. 15. Plastic film according to one or more of the previous existing claims or in particular according thereto, thereby ge indicates that the external antistatic is a hygrosko The chemical substance is that it is, for example, glycerol, Polyols or polyglycols.