DE102008039279A1 - Transparency improvement of polypropylene with metallocene waxes - Google Patents

Abstract

The invention relates to polypropylene homopolymers having a transparency> = 81%, and a process for their preparation, comprising one or more metallocene polyolefin waxes in a concentration of 0.1 to 10 wt .-%, having a molecular weight Mn in the range of 500 to 15,000 g / mol and a viscosity in the range of 30 to 10,000 mPa.s (at 170 ° C PP or 140 ° C PE).

Description

These The invention relates to the improvement of the transparency of PP-H (polypropylene Homopolymer) through the use of metallocene catalyzed polyolefin waxes, so-called metallocene waxes.

conditioned by its semi-crystalline character, PP-H is on and for an opaque polymer and therefore for fully or semitransparent Applications not suitable. It was found that this disadvantage by the addition of a minimum concentration of certain metallocene waxes can be reduced.

PP (Polypropylene) is a versatile and globally available bulk polymer. In Germany alone, about 12 million tonnes are produced each year, of which around 25% flow into the PP-H-dominated packaging market. For some fields of application, such as packaging, containers or covers, there are often requirements for a minimum transparency. For example, in order to be able to read or recognize tags or packaged goods behind, or not to minimize the light output of a light source ( PlasticsEurope "Production and Consumption Data for Plastics in Germany including Utilization 2003", Study by Consultic Marketing & Industrieberatung GmbH of 27 August 2004, pages 25 ff ).

Examples of these applications are food packaging, wrapping film, Bottles, containers, drinking cups, luminaire housings, etc. Regular PP-H is in terms of mechanical requirements and barrier properties suitable for many applications. For those with the o. G. Transparency requirements, however is in most cases the opacity of PP-H an exclusion criterion.

Polypropylene homopolymer (PP-H) is known from the prior art, polymerized from only one, repeating monomer, the propylene:

The spatial arrangement of each second C atom located Methyl group may be different. One speaks in this case of the tacticity. One knows three tactics at PP-H: isotactic, all methyl groups are on the same Page; syndiotactic, the methyl groups are uniform alternately times on the one and the other side of the chain too find and atactic, with the methyl groups being statistically distributed and are arranged arbitrarily.

Of these three possible modifications, only the isotactic variant is the most relevant and technically most useful. The uniform construction of isotactic PP favors the formation of crystalline domains, e.g. B. during cooling from the melt ( "Hostalen PP" Product Data Sheet HFKR 102 D-9020-022 of Hoechst AG, February 1990 issue, page 2 ).

Of the crystalline proportion of PP depends on many other factors which is why one gets a degree of crystallinity for regular PP from 50-70%. In general, PP-H is therefore also called semi-crystalline polymer with low transparency.

builds in addition to propylene, a second monomer, namely ethylene, in the polymer chain, we obtain the so-called PP copolymer (PP-copo). This can be depending on the arrangement of the ethylene sequences in Random copolymers (PP-R) or block copolymers (PP-B) differ, what then also z. T. significant impact on certain properties Has.

Thus, PP-B has a high toughness, especially at low temperatures. On the other hand, PP-R types are predominantly made for use in highly transparent applications (Amemiya T, Kitade S, Kozai I, Minakami S, Takahashi K, Tayano T, Japan Polychem Corp., Application PRAI JP 2004-382168 , 28.12.2004).

The arbitrary arrangement of the ethylene sequences in the PP-R polymer chain leads to a high, Amorphous share and thus to a very good transparency. Thus, the copolymerization of propylene with ethylene to PP-R is a way to obtain a polypropylene with good transparency.

The schematic structure of a PP-R from the propyl (P) and ethyl (E) groups may be as follows:
.... [- PPPEPEEPEPPPPEP -] .....

• a) PP-H Typen mit gezielt eingestellter Kristallitform (z. B. γ-Form) oder optimierter Spherulitengröße und Spherulitenverteilung. Solche Einstellungen sind z. B. mit spezieller Abkühl- oder spezifischer Katalysatortechnik erreichbar ( Saechtling, Kunststoff Taschenbuch, 28. Auflage, S. 422 Kap. 4.1.5.2 ). Dadurch sind diese PP-H Typen aber an bestimmte Verarbeitungs- oder Herstellungsverfahren gebunden und nicht, oder nur unter gewissen Aufwendungen, der breiten Masse von Verarbeitern zugänglich.
• b) Die wohl am weitesten verbreitete Technik ist die Zugabe von Nukleierungsmitteln. Bei dieser Technologie ist darauf zu achten, dass sich nur PP-H mit einer α- oder β-Kristallitform sinnvoll nukleieren lassen. Von der Vielzahl von untersuchten Nukleierungsmittel, wie Metallstearate, Benzoate, Carbonate, Phosphate, etc., haben sich vor allem solche aus der Klasse der Sorbitolester als am wirksamsten erwiesen, insbesondere im Hinblick auf mechanische und optische Eigenschaften ( „Plastics Additive Handbook”, 5th edition, Chapter 18 „Nucleating Agents for Semi-crystalline Polymers”, pages 960 ff ).
• c) Nachteile der Sorbitolester sind in erster Linie die sehr hohen Preise. Aber auch organoleptische Beeinträchtigungen in Form von Geruch sowie relativ schmale Verarbeitungsfenster, also Temperaturbegrenzungen, repräsentieren stetige Probleme.
• c) Biaxiales, also zweidimensionales, verstrecken von PP findet vor allem bei Folien für Lebensmittelverpackungen Anwendung. Bei diesen sogenannten BOPP (biaxial orientiertes PP) Folien wird zum einen durch das Ausrichten der Polymerketten die Kristallinität erhöht und zum anderen der Brechungsindex in den unterschiedlichen Ebenen vergleichmäßigt. Aber wie schon beim Beispiel a) angemerkt, ist auch BOPP an dieses eine Verarbeitungsverfahren gebunden.

Understandably, this polymerization technique is not possible with a PP-H for lack of co-monomers. For this reason, to improve the transparency of PP-H, other technologies are commonly used, such as:

• a) PP-H grades with a specific crystallite form (eg γ-form) or optimized spherulite size and spherulite distribution. Such settings are z. B. with special cooling or specific catalyst technology achievable ( Saechtling, Plastic Paperback, 28th edition, p. 422 chap. 4.1.5.2 ). However, these PP-H grades are bound to specific processing or manufacturing processes and are not available to the broad masses of processors, or only at a certain expense.
• b) Perhaps the most widely used technique is the addition of nucleating agents. With this technology, it must be ensured that only PP-H with an α- or β-crystallite form can be usefully nucleated. Of the large number of nucleating agents studied, such as metal stearates, benzoates, carbonates, phosphates, etc., especially those from the class of sorbitol esters have proven to be the most effective, in particular with regard to mechanical and optical properties ( "Plastics Additive Handbook", 5th edition, Chapter 18 "Nucleating Agents for Semi-crystalline Polymers", pages 960 ff ).
• c) Disadvantages of sorbitol esters are primarily the very high prices. But also organoleptic impairments in the form of odor and relatively narrow processing windows, ie temperature limitations, represent constant problems.
• c) Biaxial, ie two-dimensional, stretching of PP is used primarily in films for food packaging. In these so-called BOPP (biaxially oriented PP) films, on the one hand, the crystallinity is increased by aligning the polymer chains and, on the other hand, the refractive index in the different planes is made uniform. But as noted in example a), BOPP is also bound to this one processing method.

outgoing from the prior art described above and here occurring problems, it is the object of the present invention to improve the transparency of polypropylene waxes so much that These are also suitable for applications that are not yet could be served.

• – Geruch und Farbe des PP dürfen durch die transparenzverbessernde Maßnahme nicht beeinträchtigt werden. Vor allem im Bereich von Lebensmittelverpackungen werden Verschlechterungen organoleptischer Eigenschaften nicht akzeptiert und stellen ein Ausschlusskriterium dar. Ein „riechender” PP Beutel als Brotverpackung ist undenkbar und inakzeptabel;
• – Die mechanischen Eigenschaften des PP-H Endartikels dürfen nicht verschlechtert werden, da ansonsten bestimmte Anwendungen nicht mehr, oder nur noch eingeschränkt, bedient werden können. Als Beispiele seien hier Verpackungen wie Kanister, Flaschen und Becher angeführt, welche u. a. auch eine Schutzfunktion gegen äußere, mechanische Einwirkungen ausüben;
• – Lebensmittelrechtliche Zulassungen müssen erhalten bleiben. Da ein erheblicher Anteil von transparenten PP Folien in den Bereich von Lebensmittelverpackungen fließt oder fließen könnte, dürfen durch eine transparenzverbessernde Maßnahme keine Zulassungen wegfallen. So ist es u. a. Ziel, die Palette an Anwendungsmöglichkeiten für PP-H auszuweiten und nicht einzuschränken;
• – Die Verarbeitungsbedingungen eines reinen PP-H, z. B. Temperaturbereiche, sollten idealerweise unverändert übernommen werden können. Maschinenkonstruktionen und Maschineneinstellungen müssen nicht abgeändert werden. Dies würde eine starke Vereinfachung der Handhabbarkeit darstellen, es würde dazu beitragen Verarbeitungsfehler zu vermeiden und die Flexibilität erhöhen.
• – Die transparenzverbessernde Maßnahme muss von allen, der PP Verarbeitung involvierten Prozessstellen, wie Polymerherstellern, Compoundeuren, Masterbatchern und Verarbeitern, anwendbar sein. Nur dadurch ist eine breite Akzeptanz erzielbar.

In order to achieve the suitability of PP-H for applications with a minimum requirement for transparency, an economically acceptable, technically easy-to-use procedure is necessary, which must take into account the following parameters:

• - Odor and color of the PP must not be affected by the transparency improvement measure. Especially in the area of food packaging deteriorations of organoleptic properties are not accepted and are an exclusion criterion. A "smelling" PP bag as a bread package is unthinkable and unacceptable;
• - The mechanical properties of the PP-H end article must not be impaired, as otherwise certain applications can no longer be operated, or only to a limited extent. Examples include packaging such as canisters, bottles and beakers, which among other things also exert a protective function against external, mechanical effects;
• - Food law approvals must be maintained. Since a significant proportion of transparent PP films may flow or flow into the area of food packaging, no authorization should be removed by a transparency improvement measure. One of the goals is to expand and not restrict the range of applications for PP-H;
• The processing conditions of a pure PP-H, z. As temperature ranges, should ideally be able to be taken over unchanged. Machine designs and machine settings do not need to be changed. This would greatly simplify manageability, it would help avoid processing errors and increase flexibility.
• - The transparency improvement measure must be applicable by all parties involved in PP processing, such as polymer manufacturers, compounders, masterbatchers and processors. Only then is wide acceptance achievable.

Surprisingly, it has now been found that by adding metallocene waxes, such as. As Licocene PP 1302, PP 6102, PP 2602, PE 4201 or PPSI 3262, the transparency of PP-H increased to over 81%, thus achieving a significant improvement to the PP-H produced by known methods that can.

This positive effect is achieved without the color or the mechanical Properties of the articles equipped with it. It is irrelevant whether the metallocene waxes in a compound be incorporated or as a masterbatch or pure substance in the Polymer processing are metered. The dosing may be gravimetric, or else by means of a physical premix, or as Preparation or in pure form by side dosing on the extruder. A change in PP-H processing conditions, such as temperature profile, Dwell times, shearing performance in the extruder, etc. is not necessary.

For the preparation of the invention used Metallocene polyolefin waxes become metallocene compounds of the formula I used.

der Formel Ib

und der Formel Ic

This formula also includes compounds of the formula Ia,

the formula Ib

and the formula Ic

In formulas I, Ia and Ib, M ^{1 is} a Group IVb, Vb or VIb metal of the Periodic Table, for example, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, preferably titanium, zirconium, hafnium.

R ¹ and R ² are identical or different and denote a hydrogen atom, a C ₁ -C ₁₀ , preferably C ₁ -C ₃ -alkyl group, in particular methyl, a C ₁ -C ₁₀ -, preferably C ₁ -C ₃ -alkoxy group, a C ₆ -C ₁₀ , preferably C ₆ -C _8, aryl group, a C ₆ -C ₁₀ , preferably C ₆ -C _8, aryloxy group, a C ₂ -C ₁₀ , preferably C ₂ -C ₄ alkenyl group, one C ₇ -C ₄₀ -, preferably C ₇ -C ₁₀ arylalkyl group, a C ₇ -C ₄₀ -, preferably C ₇ -C ₁₂ -alkylaryl group, a C ₈ -C ₄₀ -, preferably C ₈ -C ₁₂ -aryl-alkenyl group or a halogen, preferably chlorine atom.

R ³ and R ⁴ are identical or different and denote a mononuclear or polynuclear hydrocarbon radical which can form a sandwich structure with the central atom M ¹ . R ³ and R ⁴ are preferably cyclopentadienyl, indenyl, tetrahydroindenyl, benzoindenyl or fluorenyl, it being possible for the basic units to carry additional substituents or to bridge them with one another. In addition, one of the radicals R ³ and R ^{4 may be} a substituted nitrogen atom, wherein R ^{24 has} the meaning of R ¹⁷ and is preferably methyl, tert-butyl or cyclohexyl.

R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are identical or different and denote a hydrogen atom, a halogen atom, preferably a fluorine, chlorine or bromine atom, a C ₁ -C ₁₀ -, preferably C ₁ C ₄ alkyl group, a C ₆ -C ₁₀ , preferably C ₆ -C ₈ aryl group, a C ₁ -C ₁₀ , preferably C ₁ -C ₃ alkoxy group, an -NR ¹⁶ ₂ -, -SR ¹⁶ -, -OSiR ¹⁶ ₃ -, -SiR ¹⁶ ₃ - or -PR ¹⁶ ₂ radical, wherein R ^{16 is} a C ₁ -C ₁₀ -, preferably C ₁ -C ₃ alkyl group or C ₆ -C ₁₀ -, preferably C _6- C ₈ -aryl group or in the case of Si or P-containing radicals is also a halogen atom, preferably chlorine atom or two adjacent radicals R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ or R ¹⁰ form with the connecting them C- Atoms a ring. Particularly preferred ligands are the substituted compounds of the parent compounds cyclopentadienyl, indenyl, tetrahydroindenyl, benzoindenyl or fluorenyl.

=BR¹⁷, =AIR¹⁷, -Ge-, -Sn-, -O-, -S-, =SO, =SO₂, =NR¹⁷, =CO, =PR¹⁷ oder =P(O)R¹⁷, wobei R¹⁷, R¹⁸ und R¹⁹ gleich oder verschieden sind und ein Wasserstoffatom, ein Halogenatom, vorzugsweise ein Fluor-, Chlor- oder Bromatom, eine C₁-C₃₀-, vorzugsweise C₁-C₄-Alkyl-, insbesondere Methylgruppe, eine C₁-C₁₀-Fluoralkyl-, vorzugsweise CF₃-Gruppe, eine C₆-C₁₀-Fluoraryl-, vorzugsweise Pentafluorphenylgruppe, eine C₆-C₁₀-, vorzugsweise C₆-C₈-Arylgruppe, eine C₁-C₁₀-, vorzugsweise C₁-C₄-Alkoxy-, insbesondere Methoxygruppe, eine C₂-C₁₀, vorzugsweise C₂-C₄-Alkenylgruppe, eine C₇-C₄₀-, vorzugsweise C₇-C₁₀-Aralkylgruppe, eine C₈-C₄₀-, vorzugsweise C₈-C₁₂-Arylalkenylgruppe oder eine C₇-C₄₀, vorzugsweise C₇-C₁₂-Alkylarylgruppe bedeuten, oder R¹⁷ und R¹⁸ oder R¹⁷ und R¹⁹ bilden jeweils zusammen mit den sie verbindenden Atomen einen Ring.R is ¹³

= BR ¹⁷ , = AIR ¹⁷ , -Ge, -Sn, -O-, -S-, = SO, = SO ₂ , = NR ¹⁷ , = CO, = PR ¹⁷ or = P (O) R ¹⁷ , wherein R ¹⁷ , R ¹⁸ and R ^{19 are the} same or different and a hydrogen atom, a halogen atom, preferably a fluorine, chlorine or bromine atom, a C ₁ -C ₃₀ , preferably C ₁ -C ₄ alkyl, especially methyl group , a C ₁ -C ₁₀ fluoroalkyl, preferably CF ₃ , C ₆ -C ₁₀ fluoroaryl, preferably pentafluorophenyl, C ₆ -C ₁₀ , preferably C ₆ -C ₈ aryl, C ₁ -C ₁₀ -, preferably C ₁ -C ₄ alkoxy, especially methoxy, a C ₂ -C ₁₀ , preferably C ₂ -C ₄ alkenyl, a C ₇ -C ₄₀ -, preferably C ₇ -C ₁₀ aralkyl group , a C ₈ -C ₄₀ -, preferably C ₈ -C ₁₂ -aryl-alkenyl group or a C ₇ -C ₄₀ , preferably C ₇ -C ₁₂ -alkylaryl group, or R ¹⁷ and R ¹⁸ or R ¹⁷ and R ¹⁹ each form together with the atoms connecting them a ring.

M ² is silicon, germanium or tin, preferably silicon and germanium. R ¹³ is preferably = CR ¹⁷ R ¹⁸ , = SiR ¹⁷ R ¹⁸ , = GeR ¹⁷ R ¹⁸ , -O-, -S-, = SO, = PR ¹⁷ or = P (O) R ¹⁷ .

R ¹¹ and R ¹² are the same or different and have the meaning given for R ¹⁷ . m and n are the same or different and are zero, 1 or 2, preferably zero or 1, where m plus n is zero, 1 or 2, preferably zero or 1.

R ¹⁴ and R ¹⁵ have the meaning of R ¹⁷ and R ¹⁸ .

Examples of suitable metallocenes are:
Bis (1,2,3-trimethyl) zirconium,
Bis (1,2,4-trimethylcyclopentadienyl) zirconium dichloride,
Bis (1,2-dimethylcyclopentadienyl) zirconium dichloride,
Bis (1,3-dimethylcyclopentadienyl) zirconium dichloride,
Bis (1-methylindenyl) zirconium dichloride,
Bis (1-n-butyl-3-methyl-cyclopentadienyl) zirconium dichloride,
Bis (2-methyl-4,6-di-i.propyl-indenyl) zirconium dichloride,
Bis (2-methylindenyl) zirconium dichloride,
Bis (4-methylindenyl) zirconium dichloride,
Bis (5-methylindenyl) zirconium dichloride,
Bis (alkylcyclopentadienyl) zirconium,
Bis (alkylindenyl) zirconium,
Bis (cyclopentadienyl) zirconium,
(Indenyl) zirconium,
Bis (methylcyclopentadienyl) zirconium,
Bis (n-butylcyclopentadienyl) zirconium dichloride,
To (octadecylcyclopentadienyl) zirconium,
Bis (pentamethylcyclopentadienyl) zirconium,
Bis (trimethylsilyl) zirconium,
Biscyclopentadienylzirkoniumdibenzyl,
Biscyclopentadienylzirkoniumdimethyl,
Bistetrahydroindenylzirkoniumdichlorid,
Dimethylsilyl-9 fluorenylcyclopentadienylzirkoniumdichlorid,
Dimethylsilyl-bis-1- (2,3,5-trimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilyl-bis-1- (2,4-dimethyl-cyclopentadienyl) zirconium dichloride,
Dimethylsilyl-bis-1- zirconium dichloride (2-methyl-4,5-benzoindenyl)
Dimethylsilyl-bis-1- (2-methyl-4-ethylindenyl) zirconium dichloride,
Dimethylsilyl-bis-1- (2-methyl-4-i-propylindenyl) zirconium dichloride,
Dimethylsilyl-bis-1- (2-methyl-4-phenylindenyl) zirconium dichloride,
(2-methyl-indenyl) zirconium dichloride dimethylsilyl-bis-1,
Dimethylsilyl-bis-1- (2-methyltetrahydroindenyl) zirconium dichloride,
Dimethylsilyl-bis-1-indenylzirkoniumdichlorid,
Dimethylsilyl-bis-1-indenylzirkoniumdimethyl,
Dimethylsilyl-bis-1-tetrahydroindenylzirkoniumdichlorid,
Diphenylmethylene-9-fluorenylcyclopentadienylzirkoniumdichlorid,
Diphenylsilyl-bis-1-indenylzirkoniumdichlorid,
Ethylene-bis-1- zirconium dichloride (2-methyl-4,5-benzoindenyl)
Ethylene-bis-1- (2-methyl-4-phenylindenyl) zirconium dichloride,
Ethylene-bis-1- (2-methyl-tetrahydroindenyl) zirconium dichloride,
Ethylene-bis-1- (4,7-dimethyl-indenyl) zirconium dichloride,
Ethylene-bis-1-indenylzirkoniumdichlorid,
Ethylene-bis-1-tetrahydroindenylzirkoniumdichlorid,
Indenyl-cyclopentadienyl zirconium
Isopropylidene (1-indenyl) (cyclopentadienyl) zirconium dichloride,
Isopropylidene (9-fluorenyl) (cyclopentadienyl) zirconium dichloride,
(2-methyl-indenyl) zirconium dichloride phenylmethylsilyl-bis-1-,
and in each case the alkyl or aryl derivatives of these metallocene dichlorides.

To activate the single-center catalyst systems suitable cocatalysts are used. Suitable cocatalysts for metallocenes of the formula I are organoaluminum compounds, in particular alumoxanes or else aluminum-free systems such as R ²⁰ _x NH ₄ -x BR ²¹ ₄ , R ²⁰ _x PH _4-x BR ²¹ ₄ , R ²⁰ ₃ CBR ²¹ ₄ or BR ²¹ ₃ , In these formulas, x is a number from 1 to 4, the radicals R ²⁰ are identical or different, preferably identical, and are C ₁ -C ₁₀ -alkyl or C ₆ -C ₁₈ -aryl or two radicals R ²⁰ form together with the they join a ring and the radicals R ²¹ are the same or different, preferably the same, and are C ₆ -C ₁₈ -aryl which may be substituted by alkyl, haloalkyl or fluorine. In particular, R ^{20 is} ethyl, propyl, butyl or phenyl and R ^{21 is} phenyl, pentafluorophenyl, 3,5-bis-trifluoromethylphenyl, mesityl, xylyl or tolyl.

additionally Often a third component is required to get one To ensure protection against catalyst poisons. For this are organoaluminum compound such. Triethylaluminum, Tributylaluminum and other and mixtures suitable.

ever according to the method can also supported single-center catalysts come for use. Preference is given to catalyst systems in which the residual contents of support material and cocatalyst one Do not exceed a concentration of 100 ppm in the product.

to Improving the transparency of PP-H can be metallocene catalyzed, unmodified but also grafted polyolefin waxes are used. For reasons of compatibility in polypropylene unmodified polyolefin metallocene waxes are to be preferred, wherein Within this product range, the PP metallocene waxes as have been found particularly suitable.

Usable according to the invention Metallocene waxes have a molecular weight Mn in the range of 500 to 15000 g / mol, preferably in the range of 1000 to 13000 and / or a viscosity in the range of 30 to 10,000 mPa.s, preferably from 50 to 8000 (measured at 170 ° C for PP waxes and 140 ° C for PE (polyethylene) waxes). The metallocene waxes are in concentrations in the range of 0.1-10 % By weight, preferably from 1 to 5% by weight, based on the total weight the mixture used.

When adding the metallocene waxes shown in the diagram 1, such as. As Licocene ^® PP 1302, PP 6102, PP 2602, PE 4201 or PPSI 3262, it is irrelevant whether it is an isotactic, syndiotactic or atactic PP-H. Also, the effect is not limited to a certain viscosity range of the PP-H, so that a transparency improvement in an MFI (melt flow index) range of 0.2-50 g / 10 min., But especially in the range of 0.3-40 g / 10 min (at 230 ° C / 2.16 kg) is achieved.

The present invention also relates to a process for the preparation of the polypro according to the invention pylene homopolymer waxes having a transparency ≥ 81% by mixing polypropylene homopolymer waxes with 0.1 to 10 wt.% Of one or more metallocene waxes having a molecular weight Mn in the range of 500 to 15000 g / mol and a viscosity in the range of 30 to 10,000 mPa · s (at 170 ° C or 140 ° C), melting and then extruding and granulating the mixture.

The Premixing of the individual components can be advantageous and can be carried out at room temperature in a suitable mixing apparatus.

at The mixture can heat energy over friction, over separate heating of the mixing trough or introduced in both ways become. An advantage is a pre-tempering to about 25 ° C. considered. Higher starting temperatures during hot mixing lead to clumping of the carrier and to the formation of Bottom sediments. Cooling of the mixing trough after the Last mixing phase to the pre-temperature is also advantageous.

at the preparation of the highly transparent PP homopolymers becomes more convenient Also worked with an initial mixing process. First, a mixture of the individual components is produced. The mixture is done with appropriate mixing technique.

The However, blending can be omitted when considering the individual components a recipe directly feeds the extrusion line. The said mixture is then removed by means of a suitable metering device fed to an extrusion plant. In general, these are Single or twin screw extruder, but it can also be continuous and discontinuous kneaders or compactors find use. The subsequent granulation takes place via strand and Kopfgranulierung, but also spraying is possible.

The highly transparent polypropylene homopolymers according to the invention are particularly suitable for the production of polypropylene articles by injection molding, extrusion, thermoforming, extrusion blow molding, sintering, Rotomoulding, pressing or calendering.

A improved transparency of PP homopolymer plays a major role PP films in layer thicknesses of 25-1000 μm and PP thick wall articles in the thickness ranges above 1 mm a roll. Applications are films such. B. cover films, Protective films, packaging films, etc. with a blow-mold or Calendering be made, or containers such as canisters, bottles, cups, etc. which z. B. in Tiefzug-, injection molding or blow molding.

at Plates limit the application interests predominantly on those which are produced by extrusion or injection molding and Z. B. for covers, construction purposes or as Use carrier plates.

Examples:

The results of the study presented in Diagram 1 were generated with a regular PP-H extrusion type (Moplen HF 500 N), MFI 12 (230 ° / 2.16 kg). For this purpose, the additives were mechanically mixed with the polymer powder and then extruded once with a standard twin-screw extruder (Leistritz) and granulated. These granules were then sprayed into 1 mm thick test plates on an Arburg injection molding machine. The processing conditions corresponded to the usual practice for this polymer in all steps. Diagram 1

For a more detailed differentiation of the graphically displayed results in Diagram 1, the recipes are summarized in tabular form in the overview below. Table 1 Transparency [%] recipe 81.41 3.0 PP 1302 81.53 3.0 PP 6102 81.26 0.5 pp 6102 81.06 0.5 PE 4201 81.20 3.0 PP 6102 80.69 PP-H blank 81.27 3.0 PPSI 3262 81.25 3.0 PE 4201 81.46 3.0 PP 2602 81.31 0.5 PPSI 3262

By The addition of Licocene waxes will not be any other finishing process or their effects for PP-H. For example Dyeing with pigments, stabilizing with additives, such as Antioxidants or sunscreens, antistatic agents, Etc.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - JP 2004-382168 [0010]

Cited non-patent literature

• - PlasticsEurope "Production and Consumption Data for Plastics in Germany Including Recycling 2003", Study by Consultic Marketing & Industrieberatung GmbH of 27 August 2004, pages 25 et seq. [0003]
• - "Hostalen PP" Product Data Sheet HFKR 102 D-9020-022 of Hoechst AG, February 1990 edition, page 2 [0007]
• - Saechtling, Plastic Paperback, 28th edition, p. 422 ch. 4.1.5.2 [0013]
• - "Plastics Additive Handbook", 5th edition, Chapter 18 "Nucleating Agents for Semi-crystalline Polymers", pages 960 ff. [0013]

Claims (7)

Polypropylene homopolymer with a transparency ≥ 81%, containing one or more metallocene polyolefin waxes in one Concentration of 0.1 to 10% by weight, with a molecular weight Mn in the range of 500 to 15,000 g / mol and a viscosity in the range of 30 to 10,000 mPa · s (at 170 ° C PP or 140 ° C PE). Metallocene wax-containing polypropylene homopolymer according to claim 1, characterized in that the melt index (MFI) in the range of 0.2-50 g / 10 min. (at 230 ° C / 2.16 kg). Polypropylene homopolymer according to claim 1, characterized in that the molecular weight Mn of the metallocene waxes contained is in the range of 1000 to 13000 g / mol. Polypropylene homopolymer according to at least one of previous claims, characterized in that the viscosity the metallocene waxes contained, measured in the melt at 170 ° C. (PP) or 140 ° C (PE), in the range of 50 to 8000 mPa · s lies. Polypropylene homopolymer according to at least one of preceding claims, characterized in that the metallocene waxes contained therein by direct polymerization the monomers, for. As propylene and / or ethylene, with the aid of metallocene catalysts were manufactured. Process for the preparation of polypropylene homopolymer waxes having a transparency ≥ 81% by blending polypropylene homopolymer waxes with 0.1 to 10 wt.% Of one or more metallocene waxes with a Molecular weight Mn in the range of 500 to 15000 g / mol and a Viscosity in the range of 30 to 10,000 mPa · s (at 170 ° C or 140 ° C), melting and then Extrude and granulate the mixture. Use of polypropylene homopolymers after at least any one of claims 1 to 5 for the production of polypropylene articles by injection molding, extrusion, thermoforming, extrusion blow molding, sintering, Rotomoulding, pressing or calendering.