KR100947800B1 - Propylene copolymer compositions having a good low-temperature impact toughness and a high transparency - Google Patents

Abstract

The present invention relates to propylene copolymer compositions comprising: A) at least one containing propylene polymer containing 0 to 10% by weight of olefins other than propylene and B) at least 5 to 40% by weight of olefins other than propylene. The propylene copolymer, where propylene polymer A and propylene copolymer B, are in separate phases and the propylene copolymer composition has a haze value of 30% or less, based on a path length of 1 mm of the propylene copolymer composition. And the brittle / tough transition temperature of the propylene copolymer composition is below -15 ° C.

Description

Propylene copolymer composition having excellent low temperature impact strength and high transparency {PROPYLENE COPOLYMER COMPOSITIONS HAVING A GOOD LOW-TEMPERATURE IMPACT TOUGHNESS AND A HIGH TRANSPARENCY}

The present invention relates to a propylene copolymer composition, a method for producing a propylene copolymer composition, and relates to the use of the propylene copolymer composition of the present invention for producing fibers, films or molds, and also to the propylene copolymer composition of the present invention. It relates to a fiber, a film or a mold to contain.

Propylene polymers are one of the most frequently used types of plastics at present. Commonly used propylene polymers have an isotactic structure. These can be processed to form shaped bodies having advantageous mechanical properties, in particular high strength, stiffness and shape stability. Consumer products consisting of propylene polymers are used in a wide variety of applications, for example as plastic containers, household or office supplies, toys or laboratory necessities. However, products known in the art do not have the combination of low temperature impact strength and good transparency and good stress whitening behavior required for many applications.                 

In particular, multiphase propylene copolymers having good impact strength at low temperatures can be produced by the Ziegler-Natta catalyst system in multistage polymerization reactions. However, the introduction of ethylene-propylene copolymers with high proportions of ethylene into the polymer matrix, which is necessary to increase the low temperature impact strength, makes the multiphase propylene copolymer cloudy. Poor miscibility of the flexible phase with the polymer matrix leads to phase separation and thus turbidity and poor transparency values of the heterogeneous copolymer. In addition, ethylene-propylene rubbers produced by conventional Ziegler-Natta catalysts also have very heterogeneous compositions.

It is also known that polyphase propylene copolymers can be prepared using metallocene catalyst systems. Propylene polymers prepared using metallocene catalyst systems have low extractable content, uniform comonomer distribution and good sensory performance.

The polyphase propylene copolymers disclosed in WO 94/28042 have the disadvantage that they have a very low melting point, which adversely affects the stiffness and thermal deformation resistance of the copolymer. The intensity is also not satisfactory yet.

EP-A 433 986 discloses polyphase propylene copolymers having a syndiotactic structure obtained using certain metallocene catalyst systems. The propylene copolymer composition has a relatively low melting point and nodically low stiffness and low heat distortion resistance.

 EP-A 1 002 814 describes polyphase propylene copolymers that show an excellent balance between stiffness, impact strength and thermal strain resistance.                 

WO 01/48034 relates to metallocene compounds which enable propylene copolymers having high molar mass and high copolymerized ethylene content to be obtained under industrially suitable polymerization reaction conditions.

However, the polyphase propylene copolymers disclosed in the prior art have the disadvantage that a satisfactory combination of low temperature impact strength and good transparency and at the same time good stress whitening has not been achieved. The product also has unsatisfactory strength at low temperatures or still unsatisfactory values for transparency and stress whitening.

Overcoming the disadvantages of the prior art described above, having a combination of good impact strength and good transparency and stress whitening at low temperatures, and also relatively high melting point, with low extractable content, uniform comonomer distribution and good sensory inspection, It is an object of the present invention to provide a propylene copolymer composition having high stiffness and good heat distortion resistance.

It has been found that this object is achieved by a propylene copolymer composition containing:

A) propylene polymers containing olefins other than propylene in 0 to 10% by weight and

B) at least one propylene copolymer containing from 5 to 40% by weight of olefins other than propylene,

Where propylene polymer A and propylene copolymer B are in separate phases

The propylene copolymer composition has a haze value of 30% or less, based on the path length of 1 mm of the propylene copolymer composition, and the brittle / tough transition temperature of the propylene copolymer composition is -15 degrees C or less.

Further, the method of producing the propylene copolymer composition, the use of the propylene copolymer composition of the present invention for producing fibers, films or molds, and also the fibers, films containing the propylene copolymer composition of the present invention, preferably as main components Or found a template.

Propylene polymer A and component B present in the propylene copolymer composition of the present invention are present in separate phases. Propylene copolymer compositions having the above structure are also referred to as multiphase propylene copolymers, heterogeneous propylene copolymers or propylene block copolymers.

In the multiphase propylene copolymer composition of the present invention, propylene polymer A usually forms a three-dimensional coherent phase into which the phase of propylene copolymer B is inserted. The in-phase, in which one or more other phases are dispersed, is often referred to as a matrix. The matrix also constitutes the major weight ratio of the polymer composition.

In the multiphase propylene copolymer composition of the present invention, propylene copolymer B is generally dispersed in finely divided form in the matrix. In addition, the diameter of the isolated region of propylene copolymer B then is usually between 100 nm and 1000 nm. Preference is given to structures having a length in the range from 100 nm to 1000 nm and a thickness in the range from 100 to 300 nm. Determination of the individual phase structure of the propylene copolymer composition can be performed, for example, by evaluation of a contrasted transmission electron microscope (TEM).

In order to prepare the propylene polymer present in the propylene copolymer composition of the present invention, one or more additional olefins are used as monomer in addition to propylene. As comonomers in propylene copolymer B and optionally propylene polymer A, all olefins other than propylene, in particular α-olefins, ie hydrocarbons with terminal double bonds, are possible. Preferred α-olefins are linear or branched C ₂ -C ₂₀ -1-alkenes other than propylene, in particular linear C ₂ -C ₁₀ -1-alkenes or branched C ₂ -C ₁₀ -1-alkenes, for example 4-methyl-1-pentene, conjugated and nonconjugated dienes such as 1,3-butadiene, 1,4-hexadiene or 1,7-octadiene or vinylaromatic compounds such as styrene or substituted styrene to be. Suitable olefins also include olefins in which the double bond is part of a cyclic structure that may comprise one or more ring systems. Examples are cyclopentene, norbornene, tetracyclododecene or methylnorbornene or diene, for example 5-ethylidene-2-norbornene, norbornadiene or ethylnorbornadiene. It is also possible to copolymerize mixtures of two or more olefins and propylene. Particularly preferred olefins are ethylene and linear C ₄ -C ₁₀ -1-alkenes, for example 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, in particular ethylene and / or 1 -Butene.

The propylene polymer A present in the propylene copolymer composition of the invention can be a propylene homopolymer or a propylene copolymer containing up to 10% by weight of olefins other than propylene. Preferred propylene copolymers contain 1.5 to 7% by weight of olefins other than propylene, in particular 2.5 to 5% by weight. As comonomer, preference is given to using ethylene or linear C ₄ -C ₁₀ -1-alkenes, or mixtures thereof, in particular ethylene and / or 1-butene. Propylene Polymer A preferably has an isotactic structure, which means that all methyl moieties are arranged on the same side of the polymer chain, with a few exceptions.

Component B present in the propylene copolymer composition of the present invention consists of at least one propylene copolymer containing from 5 to 40% by weight of olefins other than propylene. It is also possible for two or more propylene copolymers different from each other to be present as component B; They may differ in terms of both the amount and type of copolymerized olefin (s) other than propylene. Preferred comonomers are ethylene or linear C ₄ -C ₁₀ -1-alkenes or mixtures thereof, in particular ethylene and / or 1-butene. In a further preferred embodiment, monomers comprising two or more double bonds, for example 1,7-octadiene or 1,9-decadiene, are additionally used. The content of olefins other than propylene in the propylene copolymer is generally from 7 to 25% by weight, preferably from 10 to 20% by weight, particularly preferably from 12 to 18% by weight and in particular from 14% by weight to propylene copolymer B. 17 wt%.

The weight ratio of propylene polymer A to propylene copolymer B may vary. It is preferably 90:10 to 60:40, particularly preferably 80:20 to 60:40 and very particularly preferably 70:30 to 60:40. Here, propylene copolymer B includes all propylene copolymers forming component B.

The propylene copolymer composition of the present invention is 30% or less, preferably 25% or less, particularly preferably 15% or less and very particularly preferably 12% or less, based on the path length of the propylene copolymer composition of 1 mm. It has a haze value. The haze value is a measure of the turbidity of the material and is therefore a parameter characterizing the transparency of the propylene copolymer composition. The smaller the haze value, the higher the transparency. In addition, the haze value also depends on the path length. The thinner the layer, the smaller the haze value. Haze values are generally measured according to standard ASTM D 1003, and different test specimens may be used, for example injection-molded test specimens having a thickness of 1 mm, or films having a thickness of, for example, 50 μm. . According to the invention, the propylene copolymer composition is characterized by the haze value of injection-molded test specimens having a thickness of 1 mm.

In addition, the propylene copolymer composition of the present invention has a brittle / rigid transition temperature of -15 ° C or lower, preferably -18 ° C or lower and particularly preferably -20 ° C or lower. Very particular preference is given to brittle / rigid transition temperatures of -22 ° C or lower, in particular -26 ° C or lower.

The propylene polymer is a rigid material at room temperature, ie plastic deformation occurs only under mechanical stress before the material breaks. However, at lower temperatures, the propylene polymer shows brittle fractures, ie the fractures occur substantially without deformation or at high propagation rates. A parameter describing the temperature at which the deformation changes from stiff to brittle is the "brittle / stiff transition temperature".

In the propylene copolymer composition of the present invention, propylene polymer A is generally present as a matrix, and propylene copolymer B, which normally has a lower stiffness than the matrix and acts as an impact modifier, is dispersed therein in finely divided form. The impact modifier not only increases the strength at elevated temperatures, but also lowers the brittle / rigid transition temperature. For the purposes of the present invention, the brittle / rigid transition temperature is determined by a puncture test according to ISO 6603-2 in which the temperature is reduced in successive steps. The force / displacement graph recorded in the fracture test enables a conclusion regarding the deformation of the test specimen at each drawn temperature, thus enabling the brittle / stiffness transition temperature to be determined. To characterize the specimen according to the invention, the temperature is reduced in steps of 2 ° C. and the brittle / stiff transition temperature is defined as the temperature at which the total strain is at least 25% of the average total strain of the previous five measurements; Here, the total strain is the displacement that the punch moves through when the force passes through and falls to 3% of this maximum force. For specimens that do not show steep transitions and none of the measurements meet certain criteria, the total strain at 23 ° C. is used as reference and the brittle / stiffness transition temperature is at least 25 of the total strain at 23 ° C. Temperature less than%.

  In addition, the propylene copolymer composition of the present invention shows good stress whitening. For the purposes of the present invention, stress whitening is the occurrence of white pigmentation in stressed areas when the polymer is exposed to mechanical stress. In general, white pigmentation is assumed to be due to small voids that form in the polymer under mechanical stress. Good stress whitening means that there are no or only very few areas with white pigmentation under mechanical stress.

One way to measure stress whitening is to expose a defined test specimen to a defined impact stress and then measure the size of the resulting white spot. Thus, in the dome method, the falling dart falls onto the test specimen in the falling dart device according to DIN 53443 part 1. In this method, a falling dart having a mass of 250 g and a 5 mm diameter punch are used. The dome radius is 25 mm and the drop is 50 cm. The test specimen used is an injection-molded circular disk having a diameter of 60 mm and a thickness of 2 mm, each test specimen being subjected to a single impact test only. The stress whitening is reported as the diameter of the visible stress whitening area in mm: the value reported in each case is the average of five test specimens, each value on the injection molding phase on the opposite side of the circular disk on which the impact occurs. It is measured as the average of two values in the flow direction and its vertical direction.

The propylene copolymer composition of the present invention shows no or only very small stress whitening as measured by the dome method at 23 ° C. In the case of preferred propylene copolymer compositions, values of 0 to 8 mm, preferably 0 to 5 mm and in particular 0 to 2.5 mm are measured by the dome method at 23 ° C. Very particularly preferred propylene copolymer compositions show no stress whitening in tests conducted by the dome method at 23 ° C.                 

The propylene copolymer compositions of the present invention generally contain conventional amounts of conventional additives known to those skilled in the art, such as stabilizers, lubricants and mold release agents, fillers, nucleating agents, antistatic agents, plasticizers, salts, pigments or flame retardants. It further contains. In general, they are introduced upon the granulation of the powder product obtained in the polymerization reaction.

Conventional stabilizers include antioxidants such as sterically hindered phenols, treatment stabilizers such as phosphite or phosphonite, acid scavengers such as calcium stearate or zinc stearate or dehydrotalcite, steric hindrance Amines or UV stabilizers. Generally, the propylene copolymer composition of the present invention contains up to 2% by weight of one or more stabilizers.

Suitable lubricants and release agents are, for example, fatty acids, calcium or zinc salts of fatty acids, fatty acid amides or low molecular weight polyolefin waxes, which are usually used at concentrations up to 2% by weight.

Possible fillers are, for example, talc, chalk or glass fibers, which are usually used in amounts up to 50% by weight.

Examples of suitable nucleating agents are inorganic additives such as talc, silicon or kaolin, salts of monocarboxylic or polycarboxylic acids, for example sodium benzoate or aluminum tert-butylbenzoate, dibenzylidene sorbitol Or C ₁ -C ₈ -alkyl-substituted derivatives thereof, for example methyldibenzylidenesorbitol, ethyldibenzylidenesorbitol or dimethyldibenzylidenesorbitol or salts of diesters of phosphoric acid, for example sodium 2,2 '-Methylenebis (4,6-di-tert-butylphenyl) phosphate. The nucleating agent content of the propylene copolymer composition is generally at most 5% by weight.

Such additives are generally commercially available and are described, for example, in Gachter / Muller, Plastics Additives Handbook, 4th Edition, Hansa Publishers, Munich, 1993.

In a preferred embodiment, the propylene copolymer composition of the present invention comprises 0.1 to 1% by weight, preferably 0.15 to 0.25% by weight of the nucleating agent, in particular dibenzylidene sorbitol or dibenzylidene sorbitol derivatives, particularly preferably dimethyldibenzyl It contains lidene sorbitol.

The properties of the propylene copolymer composition of the present invention are essentially determined by the glass transition temperature of propylene copolymer B. One method of measuring the glass transition temperature of propylene copolymer B present in the propylene copolymer composition is the test of the propylene copolymer composition by DMTA (Dynamic Mechanical Thermal Analysis), where the deformation of the sample under the action of the flow vibration force Measured as a function of temperature. Here, both the amplitude and phase shift of the strain with respect to the applied force are measured. Preferred propylene copolymer compositions range from -20 ° C to -40 ° C, preferably from -25 ° C to -38 ° C, particularly preferably from -28 ° C to -35 ° C and very particularly preferably from -31 ° C to -34 ° C. Has a glass transition temperature of propylene copolymer B.

The glass transition temperature of propylene copolymer B is essentially determined by their composition, in particular by the proportion of copolymerized comonomers other than propylene. The glass transition temperature of propylene copolymer B can thus be controlled via the type of monomers used in the polymerization reaction of propylene copolymer B and their proportions. For example, in the case of a propylene copolymer composition prepared using propylene-ethylene copolymer as propylene copolymer B, the ethylene content of 16% by weight corresponds to a glass transition temperature of -33 ° C to -35 ° C.

The composition of propylene copolymer B present in the propylene copolymer composition of the present invention is preferably uniform. This distinguishes them from conventional heterogeneous propylene copolymers that are polymerized using Ziegler-Natta catalysts, since the use of Ziegler-Natta catalysts blocks the comonomers into the propylene copolymer at low comonomer concentrations regardless of the polymerization process. (blockwise) causes an introduction. For the purposes of the present invention, the term "blocked introduced" indicates that two or more comonomer units follow each other directly.

In the case of the preferred propylene copolymer composition obtained from propylene and ethylene, the structure of propylene-ethylene copolymer B can be measured by ¹³ C-NMR spectroscopy. Evaluation of the spectra is a prior art and is described, for example, in HN Cheng, Macromolecules 17 (1984), pp. 1950-1955 or in L. Abis et al., Makromol. Chemie 187 (1986), pp. 1877-1886, using the methods described by those skilled in the art. The structure can then be described by the ratio of "PE _X " and "PEP", where PE _X refers to propylene-ethylene units having two or more consecutive ethylene units, and PEP is isolated between two propylene units Reference is made to propylene-ethylene units having ethylene units. Preferred propylene copolymer compositions obtained from propylene and ethylene have a PEP / PE _X ratio of at least 0.75, preferably at least 0.85 and particularly preferably in the range from 0.85 to 2.5 and in particular in the range from 1.0 to 2.0.

Also preferred is a propylene copolymer B having an isotactic structure relative to the propylene units introduced thereafter.

The properties of the propylene copolymer composition of the present invention are also determined by the viscosity ratio of propylene copolymer B and propylene polymer A, ie the molar mass of the dispersed phase to the molar mass of the matrix. In particular, this affects transparency.

To determine the viscosity ratio, the propylene copolymer composition can be fractionated by TREF fractionation (Temperature Rising Elution Fractionation). Propylene copolymer B is then a mixed fraction which is eluted by xylene to temperatures up to and including 70 ° C. Propylene copolymer A is obtained from mixed fractions eluted by xylene at temperatures above 70 ° C. The shear viscosity of the polymer is measured on the components obtained by this method. The measurements are usually based on ISO 6721-10 using a rotary viscometer with a plate / plate structure, diameter = 25 mm, amplitude = 0.05-0.5, preheat time = 10-12 minutes, at a temperature of 200 to 230 ° C. Is performed by. The ratio of the shear viscosity of propylene copolymer B to the shear viscosity of propylene polymer A is then reported at a shear rate of 100 s ⁻¹ .

In a preferred propylene copolymer composition, the ratio of the shear viscosity of propylene copolymer B to propylene polymer A at a shear rate of 100 s ⁻¹ is in the range of 0.3 to 2.5, preferably 0.5 to 2 and particularly preferably 0.7 to 1.75.

The propylene copolymer composition of the present invention preferably has a narrow molar mass distribution M _w / M _n . For the purposes of the present invention, the molar mass distribution M _w / M _n is the ratio of weight average molar mass M _w to number average molar mass M _n . The molar mass distribution M _w / M _n is preferably in the range of 1.5 to 3.5, particularly preferably in the range of 2 to 2.5 and in particular in the range of 2 to 2.3.

The molar mass M _n of the propylene copolymer composition of the invention is preferably in the range of 20,000 g / mol to 500,000 g / mol, particularly preferably in the range of 50,000 g / mol to 200,000 g / mol and very particularly preferably 80,000 It is the range of g / mol-150,000 g / mol.

The present invention also provides for the production of propylene polymers present in the propylene copolymer compositions of the present invention. This is preferably carried out in a multistage polymerisation process which generally comprises at least two successive polymerisation stages which are carried out in a reactor cascade. It is possible to use conventional reactors used for the production of propylene polymers.

The polymerization reaction can be carried out by known methods in bulk, suspension, gaseous or supercritical media. This can be done batchwise or preferably continuously. Solution methods, suspension methods, stirred gas phase methods or gas phase fluidization-bed methods are possible. As solvent or suspension medium, it is possible to use inert hydrocarbons such as isobutane or the monomers themselves. It is also possible to carry out one or more reaction steps of the invention in two or more reactors. The size of the reactor is not essential to the process of the present invention. This depends on the emissions achieved in the individual reaction zone (s).

Preference is given to the process in which the polymerization reaction takes place from the gas phase in the second stage in which the propylene copolymer (s) B are formed. The above-mentioned polymerization of propylene polymer A can be carried out in blocks, ie liquid propylene as suspension medium, or else from the gas phase. If all polymerization reactions take place from the gas phase, they preferably comprise a stirred gas phase reactor connected in series, and the powder reaction bed is carried out in a cascade operated by a vertical stirrer. The reaction bed generally consists of a polymer that polymerizes in each reactor. If the initiation polymerization of propylene polymer A is carried out in bulk, preference is given to using a cascade consisting of at least one loop reactor and at least one gas phase fluidized-bed reactor. The preparation can also be carried out in a multizone reactor.

In order to produce the propylene polymer present in the propylene copolymer composition of the present invention, it is preferred to use a catalyst system based on metallocene compounds of transition metals of Group 3, 4, 5 or 6 of the Periodic Table of the Elements.

Particular preference is given to using catalyst systems based on metallocene compounds of formula (1):

[In the formula,

M is zirconium, hafnium or titanium, preferably zirconium,

X is the same or different and each independently of the other is hydrogen or halogen or a group -R, -OR, -OS0 ₂ CF ₃ , -OCOR, -SR, -NR ₂ or -PR ₂ , where R is linear or minute Terrain C ₁ -C ₂₀ -alkyl, C ₃ -C ₂₀ -cycloalkyl, C ₆ -C ₂₀ -aryl, C ₇ -C ₂₀ -alkylaryl, which may be substituted with one or more C ₁ -C ₁₀ -alkyl radicals, or C ₇ -C ₂₀ -arylalkyl, which may contain one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements, preferably C ₁ -C ₁₀ alkyl, for example methyl, ethyl, n -Propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl, or C ₃ -C ₂₀ -cycloalkyl, for example For example cyclopentyl or cyclohexyl, wherein the two radicals X can also be bonded to one another, preferably to form a C ₄ -C ₄₀ -dienyl ligand, in particular a 2,3-dienyl ligand, or an -OR'O- group. Have Wherein the substituent R ′ is selected from the group consisting of C ₁ -C ₄₀ -alkylidene, C ₆ -C ₄₀ -arylidene, C ₇ -C ₄₀ -alkylarylidene and C ₇ -C ₄₀ -arylalkylidene It is a divalent flag

Wherein X is preferably a halogen atom or an -R or -OR group, or both radicals X form an -OR'O- group, X is particularly preferably chlorine or methyl,

L may contain C ₁ -C ₂₀ -alkylidene radicals, C ₃ -C ₂₀ -cycloalkylidene radicals, C ₆ -C ₂₀ -arylidene radicals, which may contain heteroatoms of Groups 13-17 of the Periodic Table of Elements ₇ -C ₂₀ - alkyl, O-ylidene radical, and C ₇ -C ₂₀ - aryl alkylidene divalent bridge group selected from the group consisting of radicals, or -SiMe ₂ - or -SiPh ₂ - and silicon atoms of 5 or less, such as Silyylidene group having,

Wherein L is preferably -SiMe _2- , -SiPh _2- , -SiPhMe-, -SiMe (SiMe ₃ )-, -CH ₂ -,-(CH ₂ ) ₂ -,-(CH ₂ ) ₃ -and- A radical selected from the group consisting of C (CH ₃ ) _2- ,

R ₁ is linear or branched C ₁ -C ₂₀ -alkyl, C ₃ -C ₂₀ -cycloalkyl, C ₆ -C ₂₀ -aryl, C ₇ -which may be substituted with one or more C ₁ -C ₁₀ -alkyl radicals C ₂₀ -alkylaryl or C ₇ -C ₂₀ -arylalkyl, which may include one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements, wherein R ¹ is preferably not in the α position Branched, preferably linear or branched C ₁ -C ₁₀ -alkyl groups, in particular linear C ₁ -C ₄ -alkyl groups, for example methyl, ethyl, n-propyl or n-butyl, unbranched at the α position,

R ² is a group of the formula —C (R ³ ) ₂ R ⁴ , wherein

R ³ are the same or different and each independently of each other a linear or branched C ₁ -C ₂₀ -alkyl, C ₃ -C ₂₀ -cycloalkyl, which may be substituted with one or more C ₁ -C ₁₀ -alkyl radicals, C ₆ -C ₂₀ -aryl, C ₇ -C ₂₀ -alkylaryl or C ₇ -C ₂₀ -arylalkyl, which may comprise one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements, both radicals R ³ may combine with each other to form a saturated or unsaturated C ₃ -C ₂₀ -ring,

Wherein R ³ is preferably a linear or branched C ₁ -C ₁₀ -alkyl group,

R ⁴ is hydrogen or linear or branched C ₁ -C ₂₀ -alkyl, C ₃ -C ₂₀ -cycloalkyl, C ₆ -C ₂₀ -aryl, C which may be substituted with one or more C ₁ -C ₁₀ -alkyl radicals _7- C ₂₀ -alkylaryl or C ₇ -C ₂₀ -arylalkyl, which may include one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements,

Wherein R ⁴ is preferably hydrogen,

T and T 'are divalent groups of formula (II), (III), (IV), (V) or (VI):

Wherein the atoms represented by the symbols ^* and ^** are bonded to the atoms of the compound of formula (I) represented by the same symbol,

R ⁵ are the same or different and each independently of one another is hydrogen or halogen or a C ₃ -C ₂₀ -cyclo which may be substituted by linear or branched C ₁ -C ₂₀ -alkyl, one or more C ₁ -C ₁₀ -alkyl radicals Alkyl, C ₆ -C ₂₀ -aryl, C ₇ -C ₂₀ -alkylaryl or C ₇ -C ₂₀ -arylalkyl, which may comprise one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements There is,

Wherein R ⁵ is preferably hydrogen or a linear or branched C ₁ -C ₁₀ -alkyl group, in particular a linear C ₁ -C ₄ -alkyl group, for example methyl, ethyl, n-propyl or n-butyl,

R ⁶ are the same or different and each independently of each other hydrogen or C ₃ -C ₂₀ -cycloalkyl, which may be substituted by linear or branched C ₁ -C ₂₀ -alkyl, one or more C ₁ -C ₁₀ -alkyl radicals, C ₆ -C ₂₀ -aryl, C ₇ -C ₂₀ -alkylaryl or C ₇ -C ₂₀ -arylalkyl, which may comprise one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements,

Wherein R ⁶ is preferably an aryl group of the formula (VII):

R ⁷ are the same or different and each independently of one another is hydrogen or halogen or a C ₃ -C ₂₀ -cyclo which may be substituted by linear or branched C ₁ -C ₂₀ -alkyl, one or more C ₁ -C ₁₀ -alkyl radicals Alkyl, C ₆ -C ₂₀ -aryl, C ₇ -C ₂₀ -alkylaryl or C ₇ -C ₂₀ -arylalkyl, which may comprise one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements Or two radicals R ⁷ may combine with each other to form a saturated or unsaturated C ₃ -C ₂₀ ring,

R ⁷ is preferably a hydrogen atom,

R ⁸ is hydrogen or halogen or linear or branched C ₁ -C ₂₀ -alkyl, C ₃ -C ₂₀ -cycloalkyl, C ₆ -C ₂₀ -aryl which may be substituted by one or more C ₁ -C ₁₀ -alkyl radicals , C ₇ -C ₂₀ -alkylaryl or C ₇ -C ₂₀ -arylalkyl, and may comprise one or more heteroatoms or one or more unsaturated bonds of groups 13-17 of the Periodic Table of the Elements,

Wherein R ⁸ is preferably a branched alkyl group of formula -C (R ⁹ ) ₃ , wherein

R ⁹ are the same or different and each, independently of one another, is a linear or branched C ₁ -C ₆ -alkyl group, or two or three of the radicals R ⁹ are bonded to form one or more ring systems.

It is preferred that at least one T and T 'group is substituted with a radical R ⁶ of formula (VII); It is particularly preferred that both groups are substituted with said radicals. At least one T and T 'group is a group of formula (IV) substituted by radical R ⁶ of formula (VII), the remainder having formula (II) or (IV) likewise by radical R ⁶ of formula (VII) Very particular preference is given to substitution.

Most preferred are metallocene compound based catalyst systems of formula (VIII):

Particularly useful metallocene compounds and methods for their preparation are described, for example, in WO 01/48034 and European Patent Application 01204624.9.

The metallocene compound of formula (I) is preferably used in the form of rac or pseudorac, where the form of the monk is the two T and T 'groups with respect to each other when all other substituents are ignored. It is a complex that is a batch. The metallocene mainly results in polypropylene having an isotactic structure.

It is also possible to use mixtures of various metallocene compounds or mixtures of various catalyst systems. However, preference is given to using only one catalyst system comprising one metallocene compound used for the polymerization reaction of propylene polymer A and propylene copolymer B.

Examples of useful metallocene compounds are

Dimethylsilanediyl (2-ethyl-4- (4'-tert-butylphenyl) indenyl) (2-isopropyl-4- (4'-tert-butylphenyl) indenyl) zirconium dichloride,

Dimethylsilanediyl (2-methyl-4- (4'-tert-butylphenyl) indenyl) (2-isopropyl-4- (1-naphthyl) indenyl) zirconium dichloride,

 Dimethylsilanediyl (2-methyl-4-phenyl-1-indenyl) (2-isopropyl-4- (4'-tert-butylphenyl) -1 -indenyl) zirconium dichloride,

 Dimethylsilanediyl (2-methylthiapentenyl) (2-isopropyl-4- (4'-tert-butylphenyl) indenyl) zirconium dichloride,

 Dimethylsilanediyl (2-isopropyl-4- (4'-tert-butylphenyl) indenyl) (2-methyl-4,5-benzinyl) zirconium dichloride,

Dimethylsilanediyl (2-methyl-4- (4'-tert-butylphenyl) indenyl) (2-isopropyl-4- (4'-tert-butylphenyl) indenyl) zirconium dichloride,

Dimethylsilanediyl (2-methyl-4- (4'-tert-butylphenyl) indenyl) (2-isopropyl-4-phenylindenyl) zirconium dichloride,

Dimethylsilanediyl (2-ethyl-4- (4'-tert-butylphenyl) indenyl) (2-isopropyl-4-phenyl) indenyl) zirconium dichloride and                 

Dimethylsilandiyl (2-isopropyl-4- (4'-tert-butylphenyl) indenyl) (2-methyl-4- (1-naphthyl) indenyl) zirconium dichloride

And mixtures thereof.

Preferred catalyst systems based on metallocene compounds generally further contain compounds capable of forming metallocene ions as cocatalysts. Suitable compounds of this type include strong, non-charged Lewis acids, ionic compounds with Lewis acid cations and ionic compounds containing Bronsted acid as cations. Examples are tris (pentafluorophenyl) borane, tetrakis (pentafluorophenyl) borate or salts of N, N-dimethylanilinium. Likewise open-chain or cyclic aluminoxane compounds are suitable as compounds capable of forming metallocene ions and thus cocatalysts. They are usually prepared by the reaction of trialkylaluminum with water and are generally in the form of a mixture of straight and cyclic chain molecules of various lengths. Preferred catalyst systems based on metallocene compounds are usually used in supported form. Suitable supports are, for example, porous organic or inorganic inert solids such as finely divided polymer powders or inorganic oxides such as silica gels. The metallocene catalyst system may further contain organometallic compounds of Group 1, 2 and 13 metals of the periodic table, for example n-butyllithium or aluminum alkyl.

In the preparation of the propylene polymer present in the propylene copolymer composition of the present invention, first at a temperature of usually 40 ° C. to 120 ° C. and a pressure in the range of 0.5 bar to 200 bar, in the presence or absence of additional olefins, It is preferred to form propylene polymer A in the first step by polymerizing 90% to 100% by weight of propylene. The polymers obtainable by this reaction are then subjected to 5 to 98% by weight of additional olefins and 2 to 95% by weight, usually polymerized to it in a second step, at pressures ranging from 40 ° C. to 120 ° C. and from 0.5 bar to 200 bar. Has a mixture of propylene. The polymerization reaction of propylene polymer A is preferably carried out at a pressure of 60 to 80 ° C., particularly preferably 65 to 75 ° C., and 5 to 100 bar, particularly preferably 10 bar to 50 bar. The polymerization reaction of propylene copolymer B is preferably carried out at a pressure of 60 to 80 ° C., particularly preferably 65 to 75 ° C. and 5 to 100 bar, particularly preferably 10 bar to 50 bar.

In the polymerization reaction, it is possible to use customary additives, for example molar mass regulators such as hydrogen or inert gases such as nitrogen or argon.

The amount of monomer added in each step and also the treatment conditions, for example the addition of a molar mass control agent such as pressure, temperature or hydrogen, are chosen such that the polymer formed has the desired properties. The scope of the present invention is that propylene copolymer compositions having good impact strength at the low temperature and at the same time good transparency and good stress whitening, for example the defined comonomer content of propylene copolymer B and propylene polymer A to propylene copolymer B It includes the technical lesson that it is obtainable by adjusting the viscosity ratio of.

The composition of propylene copolymer B has a significant impact on the transparency of the propylene copolymer composition of the present invention. Reduction of the comonomer content of propylene copolymer B results in improved transparency, while at the same time, however, the low temperature impact strength decreases. Increasing the comonomer content of propylene copolymer B results in an improvement in low temperature impact strength, but at the expense of transparency. At the same time, it is also possible to improve the impact strength by increasing the proportion of propylene copolymer B. Thus, the product of the present invention shows an advantageous combination of the above properties, that is, a product which is transparent and has a good low temperature impact strength at the same time is obtained. When ethylene is preferably used as comonomer, it is particularly preferred to adjust the ethylene content of propylene copolymer B to 10 to 20% by weight, in particular 12 to 18% by weight and particularly preferably about 16% by weight. The transparency of the propylene copolymer composition of the present invention is substantially independent of the proportion of propylene copolymer B present therein.

Control of the viscosity ratio of propylene polymer A to propylene copolymer B affects the dispersion of propylene copolymer B in the polymer medium and thus the transparency and mechanical properties of the propylene copolymer composition.

The propylene copolymer composition of the present invention shows good impact strength at low temperatures, which is also combined with good transparency and very good stress whitening, and also with relatively high melting point, high stiffness and good heat deformation resistance. The propylene copolymer composition also has a low extractable content, homogeneous comonomer distribution and good sensory performance. Since the brittle / rigid transition temperature is below -15 ° C, the propylene copolymer composition of the present invention can also be used in a temperature range that places high demands on the material properties of the multiphase copolymer at temperatures below freezing point. This opens up a wide range of new possibilities for use in transparency applications in the low temperature range of the propylene copolymer compositions of the present invention.

The multiphase copolymers of the invention are, for example, for the production of fibers, films or molds by injection-molding or extrusion methods, in particular for the production of injection-molded parts, films, sheets or large hollow bodies. Suitable. Possible applications are in the fields of packaging, household goods, storage and transport containers, office supplies, electrical devices, toys, laboratory necessities, auto parts and garden necessities, and in each case are particularly suitable for applications at low temperatures.

The invention is illustrated by the following preferred examples which do not limit the scope of the invention.

Examples and comparative examples were carried out using a scheme similar to Examples 98 to 102 of WO 01/48034, and Comparative Examples A, B and C correspond to Examples 98, 99 and 100 of WO 01/48034.

Preparation of Metallocene Catalyst

3 kg of Sylopol 948 was placed in the treatment filter with the filter plate facing downwards and suspended in 15 L of toluene. A 7 L 30 weight strength% MAO solution (manufactured by Albemarle) was measured with stirring at a rate such that the internal temperature did not exceed 35 ° C. After stirring for an additional hour at low stirring speed, the suspension was first filtered without applying pressure and then under nitrogen pressure of 3 bar. In parallel with the treatment of the support material, 2.0 L of a 30% weight strength MAO solution was placed in the reaction vessel and 92.3 g of lac-dimethylsilyl (2-methyl-4- (para-tert-butylphenyl) indenyl ) (2-isopropyl-4- (para-tert-butylphenyl) indenyl zirconium dichloride was added, the solution was stirred for 1 hour and left for an additional 30 minutes. The solution was then preheated with the outlet closed It was operated on a support material, after the addition was complete, the outlet was opened and the filtrate was released The outlet was then closed, the filter cake was stirred for 15 minutes and allowed to stand for 1 hour. After the outlet was opened, it was compressed from the filter cake by nitrogen pressure of 3 bar 15 L of isododecane were added to the remaining solid, the mixture was stirred for 15 minutes and filtered. And the filter cake was then dried with compressed nitrogen pressure of 3 bar. For use in the polymerization, the total amount of the catalyst was resuspended in decane Figure 15 ℓ of isopropyl.

polymerization

The process was carried out in two stirred autoclaves connected in series and equipped with free-standing helical stirrers with usable capacity of 200 L each. Both reactors contained a stirred fixed bed of finely divided propylene polymer.

Propylene was passed into the first polymerization reactor in gaseous form and polymerized with the metallocene catalyst at the average residence time shown in Table 1 at the pressure and temperature shown in Table 1. The amount of metallocene catalyst measured allowed the amount of polymer transferred from the first polymerization reactor to the second polymerization reactor to, on average, correspond to that shown in Table 1. Metallocene catalysts were weighed with Frisch propylene added to control the pressure. Triethylaluminum in the form of a 1 molar solution in heptane was likewise weighed into the reactor.

The propylene copolymer obtained in the first gas phase reactor was transferred to the second gas phase reactor with the catalyst component still active. Here, propylene-ethylene copolymer B was polymerized thereto at the total pressure, temperature and average residence time shown in Table 1. Ethylene concentration in the reactor was monitored by gas chromatography. The weight ratio of propylene polymer A formed in the first reactor [A (I))] to propylene copolymer B formed in the second reactor [B (II)] is shown in Table 1. Isopropanol (in the form of a 0.5 molar solution in heptane) was likewise weighed into the second reactor. The weight ratio of the polymer formed in the first reactor to the polymer formed in the second reactor was controlled by isopropanol weighed into the second reactor in the form of a 0.5 molar solution in heptane, which is shown in Table 1. Hydrogen was metered into the second reactor as needed to control the molar mass. The proportion of propylene-ethylene copolymer B formed in the second reactor is the difference between the amount delivered and the amount emitted according to the relationship [(Emissions from the second reactor-emissions from the first reactor) / emissions from the second reactor]. Is presented.                 

The polymer powder obtained in the polymerization reaction was mixed with the standard additive mixture in the granulation step. Granulation was carried out using a twin screw extruder ZSK 30 from Werner & Pfleiderer at a melting temperature of 250 ° C. The propylene copolymer composition obtained was 0.05 wt% Irganox 1010 (Ciba Specialty Chemicals), 0.05 wt% Irgafos 168 (Ciba Specialty Chemicals), 0.1 wt% calcium stearate and 0.22 wt% Millad 3988 ( Bis-3,4-dimethylbenzylidene sorbitol, manufactured by Milliken Chemical). The properties of the propylene copolymer composition are shown in Tables 2 and 3. Data was measured on the propylene copolymer composition after addition of additives and granulation, or on test specimens prepared there.

Assay Results for Propylene Copolymer Compositions Example 1 Example 2 Comparative Example A Comparative Example B Comparative Example C C ₂ content ( ¹³ C-NMR) [wt%] 5.7 6.2 2.7 5.1 10.2 C ₂ content of propylene-ethylene copolymer B ( ¹³ C-NMR) [% by weight] 16.1 15.7 11.6 22.1 42.3 Limit Viscosity (ISO 1628) [cm ³ / g] Propylene Polymer A Propylene-Ethylene Copolymer B  160 177  148 150  175 152  164 157  185 191 PEP ( ¹³ C-NMR) [wt%] 3.97 3.94 1.5 1.7 1.7 PE _X ( ¹³ C-NMR) [wt%] 4.31 4.00 1.0 2.4 4.4 PEP / PE _X 0.92 0.99 1.5 0.71 0.39 Glass transition temperature [℃] (DMTA, ISO 6721-7) -2 ^* / -35 ^** -2 ^* / -33 ^** -6 ^*** -2 ^* / -42 ^** -2 ^* / -56 ^** Molar mass M _n [g / mol] 82000 81000 101000 95000 106000 Molar mass distribution [M _w / M _n ] 2.1 2.2 2.1 2.1 2.0 Shear Viscosity of Propylene-Ethylene Copolymer B η ₁₀₀ ^**** 162 311 293 382 1167 Shear Viscosity of Propylene Polymer A η ₁₀₀ ^**** 353 182 313 377 404 Ratio of shear viscosity of propylene-ethylene copolymer B / propylene polymer A (ω = 100s ^-1 ) ^**** 0.5 1.7 0.9 1.0 2.9 ^* ) Glass transition temperature of propylene polymer A ^** ) Glass transition temperature of propylene-ethylene copolymer B ^*** ) Only one value is measured. This value corresponds to the mixing temperature and indicates that in the comparative example propylene polymer A and propylene-ethylene copolymer B can be mixed ^**** ) in each case at a measurement temperature of 230 ° C. and a shear rate of 100 s ⁻¹ . Shear viscosity; Except Example 1, where the measurement temperature is 220 ° C.

Use-Related Tests for Propylene Copolymer Compositions Example 1 Example 2 Comparative Example A Comparative Example B Comparative Example C MFR (230 degreeC / 2.16 kg) [g / 10min] / ISO 1133 16.2 16.5 12.3 8.7 6.9 DSC melting point [℃] / ISO 3146 156.0 155.9 156 157.0 157.0 Bikat A softening point [℃] / ISO 306 VST / A50 128 127 141 139 140 Heat distortion resistance HDT B [° C.] / ISO 75-2 meth. B 66 64 81 76 78 Tensile E Modulus [Mpa] / ISO 527 602 609 1156 1006 1093 Brittleness / Stiffness Transition Temperature [℃] -28 -23 9 -15 <-30 Charpy impact strength (+ 23 ° C) [kJ / m ² ] / ISO 179-2 / 1eU NF NF NF NF NF Charpy impact strength (0 ° C) [kJ / m ² ] / ISO 179-2 / 1eU 194 NF 163 NF NF Charpy impact strength (-20 ° C) [kJ / m ² ] / ISO 179-2 / 1eU 265 NF 28 180 130 Charpy notched impact toughness (+ 23 ° C) [kJ / m ² ] / ISO 179-2 / 1eA 41.3 49.4 7.6 43.7 48.8 Charpy Notch Impact Strength (0 ° C) [kJ / m ² ] / ISO 179-2 / 1eA 28.9 12.6 2.0 6.9 19.4 Charpy Notch Impact Strength (-20 ° C) [kJ / m ² ] / ISO 179-2 / 1eA 2.6 2.1 1.4 1.5 3.3 Haze (1 ㎜ ^* ) [%] / ASTM D 1003 15 25 12 35 68 Haze (50 μm ^** ) [%] ASTM D 1003 15 17 10 20 17 Stress Whitening (23 ℃) [mm] / Dome Method 0 0 0 9.4 12.0 NF: No fracture ^* ) Injection-molded plate with 1 mm thickness ^** ) 50 μm thick film (no dependence of haze value observed)

Compared with Comparative Example A, the propylene copolymer composition according to the invention has an improved strength, especially at low temperatures. In comparison of Comparative Examples B and C, the strength was not severely degraded and a fairly good transparency was obtained.

analysis

The preparation of test specimens required for use-related tests and the tests themselves was performed according to the standards indicated in Table 3.

In order to determine the analytical data for product fractions, the prepared polymers or polymer compositions are described in L. Wild, "Temperature Rising Elution Fractionation", Advanced Polym. Sci. 98, 1-47, 1990, in xylene, fractionated by TREF. Fractions were eluted at 40, 70, 80, 90, 95, 100, 110 and 125 ° C. and assigned to propylene polymer A prepared in reactor I or propylene copolymer B prepared in reactor II. As propylene-ethylene copolymer B, a mixed fraction of TREF eluted at temperatures up to and including 70 ° C. was used. As propylene polymer A, a mixed fraction of TREF eluting above 70 ° C. was used.

Brittleness / stiffness transition temperature was determined by the fracture test described in ISO 66032/40/20 / C / 4.4. The speed of the punch was chosen to be 4.4 m / s, the diameter of the support ring was 40 mm and the diameter of the impact ring was 20 mm. The test specimen was clamped. The structure of the test specimen was 6 cm x 6 cm at 2 mm thickness. In order to determine the temperature dependent curve, measurements were carried out using test specimens preheated / precooled to each temperature in steps of 2 ° C. at temperatures ranging from 26 ° C. to −35 ° C.

In this example, the brittle / rigid transition temperature was measured from the total strain in mm defined as the displacement that the punch moves through when the force passes through and falls to 3% of this maximum force. For the purposes of the present invention, the brittle / stiff transition temperature is defined as the temperature at which the total strain is less than at least 25% of the average total strain of the previous five measurement points.

Measurement of the haze value was performed according to standard ASTM D 1003. The value was measured for a sample containing 2200 ppm Millad 3988. The test specimen was an injection-molded plate having a 6 × 6 cm corner length and a thickness of 1 mm. Test specimens were injection molded at a melt temperature of 250 ° C. and a tool surface temperature of 30 ° C. In order to measure the haze value of the film, a film having a thickness of 50 μm was produced by compression. After 7 days of storage time at room temperature for after-crystallization, the test specimen was clamped into a clamping device in front of the inlet orifice of Hazegard System XL 211 from Pacific Scientific and the measurements were then made. The test was performed at 23 ° C. and each specimen was tested once in the middle. To obtain an average, five test specimens were tested in each case.

Stress whitening was evaluated by the dome method. In the dome method, stress whitening was measured by the falling dart apparatus specified in DIN 53443 Annex 1 using a falling dart having a mass of 250 g, a punch diameter of 5 mm and a dome radius of 25 mm. The drop was 50 cm. As the test specimen, an injection molded circular disk having a diameter of 60 mm and a thickness of 2 mm was used. Test specimens were injection molded at a melting point of 250 ° C. and a tool surface temperature of 30 ° C. The test was performed at 23 ° C., and each test specimen was subjected to only one impact test. Test specimens were provided on the support ring without first clamping and the drop darts were then separated. Five or more test specimens were tested to obtain an average value. The diameter of the visible stress whitening area is recorded in mm, which was determined by measuring the area in the direction of flow on the opposite side of the circular disk on which the impact occurs and in the direction perpendicular thereto and forming an average of the two values.

The C ₂ content and structure of the propylene-ethylene copolymer were measured by ¹³ C-NMR spectroscopy.

 E coefficients were measured according to ISO 527-2: 1993. Type 1 test specimens having a total length of 150 mm and an equilibrium of 80 mm were injection molded at a melt temperature of 250 ° C. and a tool surface temperature of 30 ° C. In order for post-crystallization to occur, the test specimens were stored for 7 days under standard conditions of 23 ° C./50% atmospheric humidity. Test unit model Z022 from Zwick-Roell was used for the test. In the measurement of the E coefficient, the displacement measuring system had a resolution of 1 μm. The test rate in the measurement of the E factor was 1 mm / min, otherwise it was 50 mm / min. The output point in the measurement of the E coefficient was in the range of 0.05% -0.25%.

The melting point was measured by DSC (differential scanning calorimeter). A first heating step up to 200 ° C. at a heating rate of 20 ° C. per minute, dynamic crystallization up to 25 ° C. at a cooling rate of 20 ° C. per minute and a second heating step up to 200 ° C. again at a heating rate of 20 ° C. per minute Using, the measurement was carried out according to ISO standard 3146. Melting point is the temperature that shows the maximum in the enthalpy versus temperature curve measured during the second heating step.

Measurement of the molar mass M _n and the molar mass distribution M _w / M _n was carried out by gel permeation chromatography (GPC) at 145 ° C. in 1,2,4-trichlorobenzene using a GPC apparatus model 150C from Waters. . Data were evaluated by HS-Entwicklungsgesellschaft fur wissenschaftliche Hard- und Software mbH, Win-GPC software from Ober-Hilbersheim. The column was measured by polypropylene standard with a molar mass of 100 to 10 ⁷ g / mol.

The determination of the limit value of the limit viscosity, ie the number of viscosity at which the polymer concentration is extrapolated to zero, was carried out in decalin at 135 ° C. according to ISO 1628.

Shear viscosity was measured by a method based on ISO 6721-10 (RDS apparatus with plate / plate structure with diameter = 25 mm, amplitude = 0.05-0.5, preheating time = 10 -12 min, T = 200-230 ° C). . The ratio of the shear viscosity of propylene copolymer B to the shear viscosity of propylene copolymer A was measured at a shear rate of 100 s ⁻¹ . The measurement temperature was 220-230 ° C.

According to ISO 6721-7, a test specimen having a dimension of 10 mm x 60 mm and a thickness of 1 mm was measured for 7 minutes at 210 ° C., 30 bar from the melt, in order to measure the glass transition temperature by DMTA. It was then stamped from the compressed sheet at a cooling rate = 15 K / min. The test specimen was clamped in the apparatus and the measurement started at -100 ° C. The heating rate was 2.5 K / min and the measurement frequency was 1 Hz.

Claims (15)

Propylene Copolymer Compositions Containing: A) propylene homopolymer and B) at least one propylene copolymer containing from 12 to 18% by weight of olefins other than propylene, Wherein propylene homopolymer A and propylene copolymer B are present as separate phases and the weight ratio of propylene homopolymer A to propylene copolymer B is 80:20 to 60:40 and the path length of 1 mm of the propylene copolymer composition Based on, the propylene copolymer composition has a haze value of 30% or less, and the brittle / tough transition temperature of the propylene copolymer composition is -15 ° C or less. delete The propylene copolymer composition of claim 1, wherein the propylene homopolymer A has an isotactic structure. The propylene copolymer composition of claim 1, wherein the olefins other than propylene are ethylene only. The propylene copolymer composition of claim 1 wherein the stress whitening value is from 0 to 8 mm, as measured by the dome method at 23 ° C. The propylene copolymer composition of claim 1, wherein copolymer B is dispersed in matrix A in finely divided form. The propylene copolymer composition of claim 1 containing from 0.1 to 1% by weight of the nucleating agent relative to the total weight of the propylene copolymer composition. The propylene copolymer composition of claim 1 wherein the glass transition temperature of propylene copolymer B as measured by DMTA (Dynamic Mechanical Thermal Analyzer) is in the range of -20 ° C to -40 ° C. The propylene copolymer composition of claim 1 wherein the ratio of shear viscosity of propylene copolymer B to shear viscosity of propylene homopolymer A at a shear rate of 100 s ⁻¹ ranges from 0.3 to 2.5. The propylene copolymer composition of claim 1 wherein the molar mass distribution M _w / M _n is in the range of 1.5 to 3.5. A process for producing the propylene copolymer composition according to claim 1, wherein a two step polymerization reaction is carried out and a catalyst system based on a metallocene compound is used. A process using the propylene copolymer composition according to claim 1 for producing fibers, films or molds. A fiber, film or mold containing the propylene copolymer composition according to claim 1 as a component. delete delete