EP1404520A2

EP1404520A2 - Multi-layered systems containing anti-static moulding materials

Info

Publication number: EP1404520A2
Application number: EP02735232A
Authority: EP
Inventors: Rüdiger Gorny; Siegfried Anders; Wolfgang Nising; Martin Döbler; Jürgen Röhner
Original assignee: Bayer MaterialScience AG
Current assignee: Covestro Deutschland AG
Priority date: 2001-04-20
Filing date: 2002-04-08
Publication date: 2004-04-07
Also published as: WO2002085613A2; TW584598B; IL158323A0; JP2004525004A; DE10119416A1; RU2003133922A; CN1518497A; MXPA03009480A; US20030031844A1; WO2002085613A3; KR20030090757A; CA2444606A1; BR0209044A

Abstract

The invention relates to layered systems made of thermoplastic moulding materials and products produced according to said layered systems, particularly boards, which have a reduced tendency for attracting dust and which do not become electrostatically charged during the production and the use thereof.

Description

Multi-layer systems containing antistatic molding compounds

The invention relates to multilayer systems made of thermoplastic molding compositions, in particular sheets, which have a lower tendency to accumulate dust and do not become electrostatically charged during manufacture and use.

Thermoplastic extruded molded articles such as Polycarbonate sheets are known, for example, from EP A 0 110 221 and are provided for a large number of applications. They are produced by extrusion and, if appropriate, coextrusion of the thermoplastics.

With plastic moldings in general and with polycarbonate sheets in particular, the accumulation of dust with the formation of dust figures is a widespread problem. See e.g. Saechtling, plastic paperback, 26th edition, Hanser Verlag, 1995, Munich, pp. 140 f. They originate from an electrostatic charge on the moldings during manufacture. Dust deposits are particularly troublesome in the case of transparent, translucent and colored thermoplastic molded bodies in bright or bright colors. Furthermore, the accumulation of dust can reduce the transparency and thereby impair the function. After all, electrostatic charges per se can pose a risk, especially when dealing with flammable substances or flammable dusts.

A known method of electrostatic charging and thus reducing dust accumulation on plastic bodies is the use of antistatic agents. Antistatic agents are described in the literature for thermoplastics (see e.g. Gächter, Müller, Plastic

Additives, Hanser Verlag, Munich, 1996, p. 749 ff), which restrict dust accumulation. These antistatic agents improve the electrical conductivity of the plastic molding compounds and thus dissipate surface charges that form during manufacture and use. This means that dust particles are less attracted and consequently there is less dust accumulation. In the case of antistatic agents, a distinction is generally made between internal and external antistatic agents. An external antistatic is applied to the plastic molding after processing, an internal antistatic is added to the plastic molding compound as an additive. For economic reasons, the use of internal antistatic agents is usually desirable, since no further steps are required

Application of the antistatic after processing is necessary. So far, few internal antistatic agents have been described in the literature, which also form completely transparent moldings, in particular with polycarbonate. JP-A 06 228 420 describes aliphatic sulfonic acid ammonium salts in polycarbonate as an antistatic. However, these compounds lead to in the polycarbonate melt

Molecular weight loss and / or turbidity due to intolerance. JP-A 62 230 835 describes the addition of 4% nonylphenylsulfonic acid tetrabutylphosphonium in polycarbonate. WO-A 01/12713 describes the use of tetraethylammonium perfluorooctane sulfonate as an antistatic in polycarbonate. A disadvantage of this compound is the appearance of a yellow color after the

Splashing.

A disadvantage of the known antistatic agents is that they have to be used in relatively high concentrations in order to achieve the antistatic effect. However, this makes the material properties of the thermoplastics undesirable

Way changed.

Extruded molded parts from thermoplastics such as polycarbonate sheets are mainly used as clear-transparent, translucent or opaque colored sheets. For reasons of cost, the sheets colored in this way are produced by adding color masterbatches to undyed or lightly blued polycarbonate during the extrusion.

As described at the beginning, many antistatic agents in polycarbonate cause yellowing or a reduction in molecular weight. If a masterbatch that is yellowish due to the antistatic agent is added during plate extrusion, the color impression of the plates changes. To compensate for this color impression, color pigments have to be readjusted. In addition, in the case of colored plates, the color is diluted by adding an antistatic masterbatch.

The maximum usable concentration of the antistatic in the polycarbonate matrix is limited by the molecular weight reduction of the polycarbonate caused by the antistatic. In the case of colored plates in particular, the color is then thinned by adding the antistatic masterbatch.

Many antistatic agents also cloud the polycarbonate.

The invention is therefore based on the object of providing moldings and extrudates from antistatic thermoplastic molding compositions whose optical quality, but also their other properties, such as e.g. their mechanical properties and heat resistance do not differ significantly from non-antistatic molding compounds and bodies.

Surprisingly, this object is achieved by producing a layer system from thermoplastic molding compositions which contain at least one special antistatic. This layer system is characterized in that it contains at least two layers and at least one of these layers contains at least one thermoplastic molding composition according to the invention, containing at least one special antistatic.

In the sense of the invention, the layer system consists of at least two layers of one or different thermoplastics, at least one layer containing a thermoplastic which contains at least one of the special antistatic agents according to the invention. The thickness of the entire layer system is preferably 21 μm to 10 cm, particularly preferably 40 μm to 15 mm and very particularly preferably 100 μm to 12 mm.

The thickness of the individual layers of the layer system is preferably 1 μm to 10 cm. The thickness of the layer or layers which the antistatic contains is preferably between 1 μm and 200 μm, preferably 20 μm to 100 μm, particularly preferably 40 μm to 60 μm. The thickness of the layer or layers which the antistatic according to the invention does not contain is between 20 μm and 10 cm. In the case of foils, the preferred thickness is between 20 and 600 μm, in the case of solid sheets between 600 μm and 15 mm and in the case of multi-wall sheets between 0.4 and 10 cm.

The following two layer structures (arrangement in the order described) are particularly preferred:

1. Layer structure

A layer containing the antistatic thermoplastic molding composition according to the invention

A layer containing thermoplastic molding compositions without the antistatic according to the invention

2. Layer structure

A layer containing the antistatic thermoplastic molding composition according to the invention. - A layer containing thermoplastic molding compositions without the antistatic agent according to the invention

A layer containing the antistatic thermoplastic molding composition according to the invention.

The individual layer systems can furthermore each independently further

Additives such as UV absorbers, thermal stabilizers, antioxidants, mold release agents medium, flame retardant additives, dyes, pigments, brighteners, glass fibers, foaming agents, nucleating agents, plasticizers, processing aids, fillers or other additives customary in the respective thermoplastics in amounts between 0.001 and 30% by weight. Those skilled in the art are familiar with the types of additives suitable and their amount (such as, for example, Gächter; Müller, Plastics Additives, Hanser Verlag, Munich 1996 or described in EP 0 839 623 AI or EP 0 500 496 AI)

The salts of type (I) are suitable as antistatic agents in the sense of the invention.

RA-SO ₃ X (I) in which

R perfluorinated linear or branched carbon chains with 1 to 30 carbon atoms, preferably 4 to 8 carbon atoms;

A is a direct bond or an aromatic nucleus, for example and preferably fluorinated or non-fluorinated o-, m- or p-phenylene;

X alkylated and / or arylated ammonium ion NR'R "R '" R "", phosphonium ion PR'R "R'" R "", sulfonium ion SR'R "R '", and substituted or unsubstituted imidazolinium ion, pyridinium ion or tropylium ion , in which

R \ R ", R" \ R "" each independently of one another or unsubstituted

Halogen, hydroxy, cycloalkyl or alkyl, in particular substituted, aromatic, cyclic or linear, branched or unbranched carbon chains with 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms, in the case of Ci to C ₃ alkyl or C ₅ -C cycloalkyl Cyclic radicals preferably those with 5 to 7 carbon atoms, particularly preferred

Methyl, ethyl, propyl, 1-butyl, 1-pentyl, hexyl, isopropyl, isobutyl, tert- Butyl, neopentyl, 2-pentyl, iso-pentyl, iso-hexyl, cyclohexyl, cyclohexylmethyl, cyclopentyl, phenyl or benzyl,

mean.

Quaternary ammonium salts NR'R "R '" R' "\

Particularly preferred quaternary ammonium salts in the sense of the invention are:

- Perfluorooctanesulfonic acid tetraethylammonium salt

Perfluorbutansulfonsäuretetraethylylammoniumsalz

Perfluoroctansulfonsäuretetrapropylammoniumsalz,

Perfluorbutansulfonsäuretetrapropylammoniumsalz,

Perfluorooctanesulfonic acid tetrabutylammonium salt, - perfluorobutanesulfonic acid tetrabutylammonium salt,

Perfluoroctansulfonsäuretetrapentylammoniumsalz,

Perfluorbutansulfonsäuretetrapentylammoniumsalz,

Perfluoroctansulfonsäuretetrahexylammoniumsalz,

Perfluorobutanesulfonic acid tetrahexylammonium salt, - N-methyl-tripropylammonium perfluorobutylsulfonate,

N-methyl-tripropylammoniumperfluoroctansulfonat,

N-ethyl perfluorobutyl sulfonate,

N-ethyl-tripropylammoniumperfluoroctansulfonat

Dimethyldiisopropylammonium perfluorobutyl sulfonate, dimethyldiisopropylammonium perfluorooctane sulfonate,

Ethyldiisopropylmethylammoniumperfluorbutylsulfonat,

Ethyldiisopropylmethylammoniumperfluoroctansulfonat,

N-methyl-tributylammoniumperfluorbutylsulfonat,

N-methyl-tributylammonium perfluorooctane sulfonate, - cyclohexyldiethylmethylammonium perfluorobutyl sulfonate,

Cyclohexyldiethylmethylammoniumperfluoroctansulfonat, Cyclohexyltrimethylammonium perfluorobutyl sulfonate, cyclohexyltrimethylammonium perfluorooctane sulfonate,

as well as the corresponding trifluoromethanesulfonates.

In particular, each of the salts mentioned is also preferably suitable.

Mixtures of sulfonic acid salts, in particular the sulfonic acid salts mentioned above, are also preferred.

The perfluoroalkylsulfonic acid ammonium salts are known or can be prepared by known methods. The salts of the sulfonic acids can be prepared by combining equimolar amounts of the free sulfonic acid with the hydroxy form of the corresponding cation in water at room temperature and concentrating the solution. Other manufacturing processes are described e.g. in DE A 19

66 931 and NL A 7 802 830 or in Pomaville et al., J. Chromatogr. (1989), Volume Date 1988, 468, pages 261-278.

The perfluoroalkylsulfonic acid ammonium salts are preferably added to the plastics in amounts of 0.001 to 2% by weight, preferably 0.1 to 1% by weight.

Thermoplastics suitable for the purposes of the invention are in particular transparent thermoplastics. Polymers of ethylenically unsaturated monomers and / or polycondensates of bifunctional reactive compounds are preferred.

Particularly suitable plastics are polycarbonates or copolycarbonates based on bisphenols, the poly- or copolyacrylates and poly- or copolymethacrylates such as by way of example and preferably polymethyl methacrylate, poly- or copolymers with styrene such as by way of example and preferably transparent polystyrene or polystyrene-acrylonitrile (SAN), transparent thermoplastic Polyurethanes, as well as polyolefins, such as exemplary and preferably transparent types of polypropylene or poly- olefins based on cyclic olefins (eg TOPAS ^® , Hoechst), poly- or copolycondensates of terephthalic acid with or without isophthalic acid, with ethylene glycol and / or cyclohexanedimethanol such as by way of example and preferably poly- or copolyethylene terephthalate (PET or CoPET) or cyclohexanedimethanol or modified PET (PETG).

Polycarbonates or copolycarbonates, in particular non-halogenated polycarbonates and / or copolycarbonates with weight-average molecular weights M _{w of} from 5000 to 100,000, preferably from 10,000 to 50,000, particularly preferably from 15,000 to 40,000, are particularly preferred.

Homopolycarbonates, copolycarbonates and thermoplastic polyester carbonates are particularly suitable. They have weight average molecular weights M _{w of} 18,000 to 40,000, preferably from 26,000 to 36,000 and in particular from 28,000 to 35,000, determined by measuring the rel. Solution viscosity in dichloromethane or in

Mixtures of equal amounts by weight of phenol / o-dichlorobenzene calibrated by light scattering.

The melt viscosity of the molding compositions containing the antistatic should preferably be lower than the melt viscosity of the molding compositions of the others

Layers.

For the production of polycarbonates for the molding compositions according to the invention, see, for example, "Schnell", Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, Interscience Publishers, New York, London, Sydney 1964, on D.C.

PREVORSEK, B.T. DEBONA and Y. KESTEN, Corporate Research Center, Allied Chemical Corporation, Moristown, New Jersey 07960, "Synthesis of Poly (ester) - carbonate Copolymers" in Journal of Polymer Science, Polymer Chemistry Edition, Vol. 19, 75-90 (1980 ), on D. Freitag, U. Grigo, PR Müller, N. Nouvertne, BAYER AG, "Polycarbonates" in Encyclopedia of Polymer Science and

Engineering, Vol. 11, Second Edition, 1988, pages 648-718 and finally on Dres. U. Grigo, K. Kircher and PR Müller "Polycarbonate" in Becker / Braun, Plastic Manual, Volume 3/1, Polycarbonate, Polyacetale, Polyester, Cellulose Ester, Carl Hanser Verlag Munich, Vienna 1992, pages 1 17 The production is preferably carried out according to the phase interface process or the melt transesterification process and is described using the phase interface process as an example.

Compounds which are preferably to be used as starting compounds are bisphenols of the general formula HO-Z-OH, in which Z is a divalent organic radical having 6 to 30 carbon atoms and containing one or more aromatic groups.

Examples of such compounds are bisphenols which belong to the group of dihydroxydiphenyls, bis (hydroxyphenyl) alkanes, indane bisphenols, bis (hydroxyphenyl) ethers, bis (hydroxyphenyl) sulfones, bis (hydroxyphenyl) ketones and α, α'-bis (hydroxy- phenyl) diisopropylbenzenes belong.

Particularly preferred bisphenols belonging to the abovementioned connecting groups are bisphenol-A (2,2-bis (4-hydroxyphenyl) propane), tetraalkylbisphenol-A, 4,4- (meta-phenylenediisopropyl) diphenol (bisphenol M), 4,4- (para-phenylene-diisopropyl) diphenol, l, l-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (BP-TMC) and optionally their mixtures. Homopolycarbonates based on bisphenol-A and copolycarbonates based on the monomers bisphenol-A and l, l-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane are particularly preferred. The bisphenol compounds to be used according to the invention are reacted with carbonic acid compounds, in particular phosgene, or diphenyl carbonate or dimethyl carbonate in the melt transesterification process.

Polyester carbonates are obtained by reacting the bisphenols already mentioned, at least one aromatic dicarboxylic acid and optionally carbonic acid equivalents. Suitable aromatic dicarboxylic acids are, for example, phthalic acid, terephthalic acid, isophthalic acid, 3,3'- or 4,4'-diphenyldicarboxylic acid and

Benzophenone. A part, up to 80 mol%, preferably from 20 to 50 mol% of the carbonate groups in the polycarbonates can be replaced by aromatic dicarboxylic acid ester groups.

Inert organic solvents used in the interfacial process are, for example, dichloromethane, the various dichloroethanes and chloropropane compounds, carbon tetrachloride, trichloromethane, chlorobenzene and chlorotoluene; chlorobenzene or dichloromethane or mixtures of dichloromethane and chlorobenzene are preferably used.

The phase interface reaction can be accelerated by catalysts such as tertiary amines, in particular N-alkylpiperidines or onium salts. Tributylamine, triethylamine and N-ethylpiperidine are preferably used. In the case of the melt transesterification process, the catalysts mentioned in DE A 42 38 123 are used.

The use of small amounts of branching agents allows the polycarbonates to be deliberately and controlled branched. Some suitable branching agents are: phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -hepten-2; 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) heptane; 1,3,5-tri- (4-hydroxyphenyl) benzene; 1,1,1-tri- (4-hydroxyphenyl) ethane; Tri- (4-hydroxyphenyl) -phenylmethane; 2,2-bis- [4,4-bis- (4-hydroxyphenyl) cyclohexyl] propane; 2,4-bis (4-hydroxyphenyl-isopropyl) -phenol; 2,6-bis (2-hydroxy-5'-methylbenzyl) -4-methylphenol; 2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) propane; Hexa- (4- (4-hydroxyphenyl-isopropyl) phenyl) orthoterephthalic acid ester; Tetra (4-hydroxyphenyl) methane; Tetra- (4- (4-hydroxyphenyl-isopropyl) phenoxy) methane; α, α α ', α α α "-Tris- (4-hydroxyphenyl) - 1,3,5 -triisopropylbenzene; 2,4-dihydroxybenzoic acid; trimesic acid; cyanuric chloride; 3,3-bis- (3-methyl- 4-hydroxyphenyl) -2-oxo-2,3-dihydroindole; 1,4-bis- (4 ', 4 "-dihydroxy-triphenyl) -methyl) -benzene and in particular: l, l, l-tri- (4th -hydroxyphenyl) ethane and 3,3-bis (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole. The optionally used 0.05 to 2 mol%, based on diphenols, of branching agents or mixtures of the branching agents can be used together with the diphenols but can also be added at a later stage in the synthesis.

As chain terminators, phenols such as phenol, alkylphenols such as cresol and 4-tert-butylphenol, chlorophenol, bromophenol, cumylphenol or mixtures thereof are preferably used in amounts of 1-20 mol%, preferably 2-10 mol% per mol of bisphenol. Phenol, 4-tert-butylphenol and cumylphenol are preferred.

Chain terminators and branching agents can be added to the syntheses separately or together with the bisphenol.

The preparation of the polycarbonates for the molding compositions according to the melt transesterification process is described by way of example in DE A 42 38 123.

Additives suitable as UV absorbers in the sense of the invention are e.g. in

EP A 0 839 623 (page 23f) and EP A 0 500 496 (page 2, connection I, and page 6f, chapter 2).

Derivatives of benzotriazole, benzophenone, triazine, and arylated cyanoacrylates and other conventional UV absorbers are particularly suitable.

UV absorbers which are particularly suitable according to the invention for the molding compositions to be used are those compounds which, owing to their absorption capacity below 400 nm, are able to effectively protect polycarbonate from UV light.

Suitable UV absorbers are in particular the compounds of the formula (I) described in WO 99/05205

wherein R ¹ and R ² are identical or different and are H, halogen, Cι-Cι ₀ alkyl, C5-C10-cycloalkyl, C ₇ -Cι ₃ aralkyl, C ₆ -Cι ₄ aryl, -OR ⁵ or - ( CO) -OR ⁵ mean with R ⁵ - H or CC ₄ alkyl,

R ³ and R ^{4 are} likewise the same or different and are H, CrC-alkyl, C ₅ -C ₆ - cycloalkyl, benzyl or C ₆ -Cι ₄ -aryl,

m is 1, 2 or 3 and n is 1, 2, 3 or 4,

as well as those of the formula (II)

where the bridge

- (CHR ³ ) _P - c- -O- (Y-0) _q - C (CHR ⁴ ) - means

R ¹ , R ² , m and n have the meaning given for formula (II),

wherein p is also an integer from 0 to 3,

q is an integer from 1 to 10,

Y -CH ₂ -CH ₂ -, - (CH ₂ ) ₃ -, - (CH ₂ ) ₄ -, - (CH ₂ ) ₅ -, - (CH ₂ ) ₆ -, or

Is CH (CH ₃ ) CH ₂ and

R ³ and R ^{4 have} the meaning given for formula (II).

Other UN absorbers suitable according to the invention are those which are substituted

Represent triazines such as 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-n-octyloxy-ρhenyl) -l, 3,5-triazine (CYASORB® UV-1164) or 2 - (4,6-Diphenyl-l, 3,5-triazin-2-yl) -5- (hexyl) oxy-phenol (Tinuvin® 1577). A particularly preferred UV absorber is 2,2-methylenebis (4- (1, 1, 3, 3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), which is commercially available under the name Tinuvin® 360 or Adeka Stab ^® LA 31 is sold. The UN absorbers mentioned in EP 0500496 AI are also suitable. The UV absorber Uvinul 3030 from BASF AG obtained in WO 96/15102, Example 1 can also be used.

Other UV absorbers suitable according to the invention are hydroxy-benzotriazoles, such as

2- (3 ', 5-' bis (l, l-dimethylbenzyl) -2'-hydroxyphenyl) benzotriazole (Tinuvin ^® 234, Ciba Specialty Chemicals, Basel), 2- (2'-hydroxy-5'- (tert-octyl) phenyl) benzotriazole (Tinuvin ^® 329, Ciba Specialty Chemicals), 2- (2'-hydroxy-3 '- (2-butyl) -5' - (tert-butyl) phenyl) benzotriazole ( Tinuvin ^® 350, Ciba Specialty Chemicals), bis (3- (2H-benzotriazolyl) -2-hydroxy-5-tert-octyl) methane, (Tinuvin ^® 360, Ciba Specialty Chemicals), 2- (4-hexoxy-2-hydroxyphenyl ) -4,6-diphenyl-1, 3,5-triazine (Tinuvin ^® 1577, Ciba Specialty Chemicals), and 2,4-dihydroxy-benzophenone (Chimasorb22 ^® , Ciba Specialty Chemicals) and 2-hydroxy-4- (octyloxy) benzophenone

(Chimasorbδl ^® , Ciba specialty chemicals).

The UV absorbers are preferred in amounts of in each case between 0.001% by weight and 20% by weight, preferably 0.01% by weight and 1% by weight, preferably between 0.1-1% by weight and very particularly preferably between 0.2 and 0.6 wt .-% used. For outdoor applications, preferably 2 to 11% by weight, preferably 3 to 10% by weight and very particularly preferably between 3 and 7% by weight are used.

Suitable stabilizers for the polycarbonates for the molding compositions according to the invention are, for example, phosphines, phosphites or Si-containing stabilizers and further compounds described in EP-A 0 839 623 (page 21, chapter 1). Examples include triphenyl phosphites, diphenylalkyl phosphites, phenyl dialkyl phosphites, tris (nonylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene diphosponite and triaryl phosphite. Triphenylphosphine and tris (2,4-di-tert-butylphenyl) phosphite are particularly preferred.

The molding composition according to the invention can also contain 0.01 to 0.5% by weight of the (partial) esters of monohydric to hexavalent alcohols, in particular glycerol, pentaerythritol or Guerbet alcohols.

Monohydric alcohols are, for example, stearyl alcohol, palmityl alcohol and Guerbet alcohols.

For example, a dihydric alcohol is glycol.

A trihydric alcohol is, for example, glycerin.

Tetravalent alcohols are, for example, pentaerythritol and mesoerythritol. Examples of pentavalent alcohols are arabite, ribite and xylitol.

Hexahydric alcohols are, for example, mannitol, glucitol (sorbitol) and dulcitol.

The esters are the monoesters, diesters, triesters, tetraesters, optionally pentaesters and hexaesters or their mixtures, in particular statistical mixtures, of saturated, aliphatic C ₁₀ to C ₃₆ monocarboxylic acids and optionally hydroxy monocarboxylic acids, preferably with saturated, aliphatic C ₁₄ to C. ₃ -monocarboxylic acids and optionally hydroxy-monocarboxylic acids.

The commercially available fatty acid esters, in particular pentaerythritol and glycerol, may contain <60% different partial esters due to the manufacturing process

Saturated, aliphatic monocarboxylic acids with 10 to 36 carbon atoms are, for example, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid,

Hydroxystearic acid, arachic acid, behenic acid, lignoceric acid, cerotinic acid and montanic acids.

Preferred saturated, aliphatic monocarboxylic acids with 14 to 22 carbon atoms are, for example, myristic acid, palmitic acid, stearic acid, hydroxystearic acid,

Arachidic acid and behenic acid.

Saturated, aliphatic monocarboxylic acids such as palmitic acid, stearic acid and hydroxystearic acid are particularly preferred.

The saturated, aliphatic to C ₃₆ -carboxylic acids and the fatty acid esters to be used according to the invention are either known as such or can be prepared by processes known from the literature. Examples of pentaerythritol fatty acid esters are those of the particularly preferred monocarboxylic acids mentioned above. Esters of pentaerythritol and glycerol with stearic acid and palmitic acid are particularly preferred.

Esters of Guerbet alcohols or of glycerol with stearic acid and palmitic acid and optionally hydroxystearic acid are also particularly preferred.

The molding composition according to the invention can furthermore contain organic dyes, inorganic color pigments, fluorescent dyes and particularly preferably optical brighteners.

All starting materials and solvents used for the synthesis of the molding compositions according to the invention which can be contaminated from their production and storage with corresponding impurities, such as particles, gel bodies, ions, solvent residues, monomer or oligomer residues or other compounds should be used as cleanly as possible.

The individual constituents can be mixed in a known manner both successively and simultaneously, both at room temperature and at elevated temperature.

The additives are incorporated into the molding compositions according to the invention, in particular the antistatic agents and UN absorbers and other additives mentioned above, in a known manner by mixing polymer granules with the additives at temperatures of about 200 to 350 ° C. in conventional units such as internal kneaders, single-screw extruders and twin-screw extruders, for example by melt compounding or melt extrusion or by mixing the solutions of the polymer with solutions of the additives in suitable organic solvents such as CH ₂ Cl ₂ , haloalkanes, halogen aromatics, chlorobenzene and xylenes and subsequent evaporation of the solvents in a known manner. The proportion of additives in the molding composition can be varied within wide limits and depends on the desired properties of the molding composition. The total proportion of additives in the molding composition is approximately up to 30% by weight, preferably 0.1 to 12% by weight, based on the weight of the molding composition.

The invention thus relates to moldings and extrudates which have been produced using the molding compositions according to the invention. The molding compounds can be used to produce foils, solid plastic sheets and multi-skin sheets (e.g. double skin sheets, triple-skin sheets etc.) and corrugated sheets. The layer systems according to the invention also include those which have an additional cover layer on one or both sides with the molding compositions according to the invention with an increased UV absorber content.

The layer systems according to the invention allow the production of shaped bodies and extrudates on which no dust figures are deposited over time, in particular of plates and shaped bodies made from them, e.g. Glazing for winter gardens, bus stops, machine covers, billboards, signs,

Protective windows, automotive glazing, windows and roofing.

Subsequent processing of the extrusion body coated with the molding composition according to the invention, such as Deep drawing or surface processing are possible and the molded bodies produced by these processes are also the subject of the patent.

Coextrusion as such is known from the literature (see, for example, EP A 0 110 221 and EP A 0 110 238). In the present case, the procedure is preferably as follows:

Extruders for producing the core layer and cover layer (s) are connected to a coextrusion adapter. The adapter is constructed in such a way that the melt forming the cover layers) is adhered to the melt of the core layer as a thin layer. The multilayer melt strand thus produced is then brought into the desired shape (multi-wall or solid sheet) in the nozzle connected subsequently. The melt is then cooled in a known manner by means of calendering (solid plate) or vacuum calibration (multi-wall plate) under controlled conditions and then cut to length. If necessary, a tempering furnace can be installed after the calibration to eliminate stresses. Instead of the adapter attached in front of the nozzle, the nozzle itself can also be designed such that the melts are brought together there.

Examples

The invention is intended to be illustrated further by the following examples, but without restricting it thereby.

Example KAdditive):

396.2 g of perfluorobutanesulfonyl fluoride (1.311 mol, Aldrich) and 78.8 g of dimethyldimethoxysilane (0.655 mol, Fluka) are placed in tert-butyl methyl ether (Aldrich) and slowly at room temperature with 151.1 g of N, N-diisopropylmethylamine

(1.311 mol, Fluka) added. The reaction solution is then stirred at room temperature for 7 h until the evolution of gas subsides and finally the precipitated product is filtered off, washed with tert-butyl methyl ether and dried. Yield 525 g of white crystals of dimethyldiisopropylammonium perfluorobutyl sulfonate.

Example 2 (additive polymer)

Makrolon ^® 2808 (linear bisphenol-A polycarbonate from Bayer AG, Leverkusen with a melt flow index (MFR) of 10 g / 10 min at 300 ° C and 1.2 kg load) is mixed with 0.05% triphenylphosphine, 0.3% 2- (2nd '-Hydroxy-3' - (2-butyl) -5'- (tert-butyl) phenyl) benzotriazole, 0.1% octadecyl-3- (3 ', 5'-di-tert-butyl-4' -hydroxyphenyl) propionate and 1.5% dimethyldiisopropylammonium perfluorobutylsulfonate (Ex. 1) compounded as described below.

Example 3 (plate production)

3 mm solid sheets A to G were made from the following molding compounds: As

Base material was Makrolon ^® 3103 (linear bisphenol-A polycarbonate of Bayer AG Leverkusen having a melt flow rate (MFR) of 6.5 g / 10 min at 300 ° C and 1, 2 kg load) are used. This was coextruded with those in Table 1 specified compounds based on Makrolon ^® 3103 (linear bisphenol-A polycarbonate from Bayer AG, Leverkusen with a melt flow index (MFR) of 6.5 g / 10 min at 300 ° C and 1.2 kg load).

The compounds were produced as follows: at 310 ° C. and 80 rpm, the UV absorber and the antistatic according to Table 1 were incorporated into the polycarbonate on a twin-screw extruder (ZSK 32, Werner & Pfleiderer) and the extrudate was then granulated.

The thickness of the coex layer is approximately 50 μm in each case.

Table 1: Composition of the compounds for the coex layers

*) Commercially available, perfluoro-1-octanesulfonic acid, tetraethylammonium salt from Bayer AG, Leverkusen

**) Commercially available, 2- (2H-benzotriazol-2-yl) -4- (l, l-dimethylethyl) -6- (2-methylpropyl) phenol from Ciba

Specialty Chemicals, Lampertheim ***) Commercially available, 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] from Ciba

Specialty Chemicals, Lampertheim ****) Manufactured by mixing granules of Makrolon 3103 and Masterbatch **** ^♦ ) Commercially available from Clariant, Muttenz, Switzerland. Antistatic masterbatch based on non-fluorinated aliphatic

Sulfonates. Example 4 (Molding Compound According to the Invention Not Coextruded):

It is an additive-free, unstabilized polycarbonate (Makrolon ^® 2808 from Bayer AG, Leverkusen) was compounded at 340 ° C on a Zweiwellenextuder with the specified amount in Table 1 of Perfluoroctansulfonsäuretetraethylammoniumsalz and the other indicated additives and then granulated.

Rectangular sheets are then sprayed from this granulate at a melt temperature of 300 ° C (155 mm x 75 mm x 2 mm) and subjected to the dust test.

Table 2: Plastic compositions

The machines and apparatus used for the production of multilayer

Solid panels are described below:

The facility consists of

the main extruder with a screw of length 33D and a diameter of 60 mm with degassing the coex adapter (feed block system), one layer on both sides a coextruder for applying the top layers with a screw

Length 25D and a diameter of 30 mm of the slot die with a width of 350 mm, the 3-roller smoothing calender, vertical roller arrangement of the roller conveyor of the protective film lamination of the take-off device of the cutting device (saw) and the deposit table.

The polycarbonate granulate of the base material is fed to the hopper of the main extruder, the coextrusion material to that of the coextruder. The respective material is melted and conveyed in the respective plasticizing system cylinder / screw. Both material melts are brought together in the coex adapter and form a bond between the rollers after leaving the nozzle and cooling. The other facilities are used for transport, surface protection and cutting the extruded sheets to length.

The plates obtained were then subjected to a colorimetric evaluation. The following measurement procedure was used:

Transmission (based on the standards ASTM E 308 / ASTM D 1003) Device: Pye-Unicam (measurement geometry: 0 ° / diffuse, calculated according to illuminant C) Yellowness index YI according to ASTM E 313.

The dust-repellent effect was tested as follows and evaluated with a standard evaluation: In order to investigate the dust accumulation in the laboratory test, the sprayed plates are exposed to an atmosphere with whirled up dust. For this purpose, a 2-1 beaker with an 80 mm long magnetic stirring bar with a triangular cross section with dust (coal dust / 20 g activated carbon, Riedel-de

Haen, Seelze, Germany, Article No. 18003) approx. 1 cm high. With help of a The dust is whirled up with a magnetic stirrer. After stopping the stirrer, the test specimen is exposed to this dust atmosphere for 7 sec. Depending on the test specimen used, more or less dust settles on the test specimen. The assessment of the dust deposits (dust figures) is carried out visually.

The table below shows that sheets which are coextruded with the molding compositions according to the invention have approximately the same yellowing (Yellowness Index) as those compared to sheets made from known, non-additive molding compositions (1), and to sheets made from other than those according to the invention Additive molding compounds (2 and 3) are clearly superior in terms of transparency or dust. Compared to plates (9-11), which use the molding compositions according to the invention, ie additives, but do not have the layer system according to the invention, the plates according to the invention show a significantly lower yellowness index.

Table 3:

As can be seen from the tables above, the desired combination of dust repellency and little impairment of the optical properties can only be achieved with the layer systems according to the invention. Furthermore, the layer systems according to the invention show excellent weather stability.

Claims

claims

1. Layer system composed of at least two layers of one or different thermoplastics, at least one layer containing a thermoplastic which contains at least one antistatic of the formula (I)

RA-SO ₃ X (I)

in which

R perfluorinated linear or branched carbon chains with 1 to 30 carbon atoms;

A is a direct bond or an aromatic nucleus;

R \ R ", R '", R "" each independently of one another unsubstituted or substituted by halogen, hydroxyl, cycloalkyl or alkyl, aromatic, cyclic or linear, branched or unbranched carbon chains with 1 to 30 carbon atoms

mean contains.

Molded bodies or extrudates, characterized in that they contain a layer system according to claim 1. A process for producing the layer system according to claim 1 by coextrusion.