Propylene random copolymer composition with reduced seal initiation temperature

Abstract

The present invention relates to a polyolefin composition suitable as a sealing layer for multilayer films, providing improved (i.e. Reduced) seal onset temperature. The polyolefin composition comprises a random copolymer of propylene and a polymer of 1-butene. The invention also relates to oriented and non-oriented films comprising said polyolefin composition and to the use of a polymer of 1-butene in a polyolefin composition comprising a propylene random copolymer for reducing the seal initiation temperature of an oriented or non-oriented film comprising the polyolefin composition. The invention allows the use of polyolefin compositions based on propylene random copolymers as sealing layers for multilayer films for high-speed packaging lines, and at the same time also provides good thermal stickiness and optical properties.

Description

[0001] This application is a divisional application of a patent application with application number 201880028761.4 filed on May 18, 2018 and invention name “Propylene random copolymer composition with reduced sealing initiation temperature”.

[0002] The present invention relates to a polyolefin composition suitable for use as a sealant layer of a multilayer film, providing an improved (i.e., reduced) seal initiation temperature. The polyolefin composition comprises propylene and one or more selected from ethylene and C4-C 12 The present invention also relates to an oriented and unoriented film comprising the polyolefin composition and a polyolefin composition (which comprises propylene and one or more selected from ethylene and C4-C 12 Use of a polymer of 1-butene in a random copolymer of propylene with a monomer of a polyolefin composition (i.e., a propylene random copolymer) for lowering the sealing initiation temperature of an oriented or non-oriented film comprising the polyolefin composition.

[0003] As is known in the art, films based on polyolefin compositions are widely used in a variety of applications. One of these applications is packaging, especially food packaging such as packaging films and containers. Such films are known for their well-balanced properties such as strength, stiffness, transparency and impact resistance.

[0004] WO 2014 / 191506 discloses a bimodal random propylene copolymer and its use for the preparation of cast films for packaging applications and thereby provides a solution which is cheaper than a comparable solution based on terpolymers, e.g. propylene polymers having both ethylene and an α-olefin as comonomers.

[0005] However, current industrial practice for high-speed packaging lines requires films, such as the seal layer of a multilayer film, with a suitably low seal initiation temperature (SIT), such as about 105° C. Likewise, there are solutions based on polyolefin terpolymers. However, comparable solutions based on propylene copolymers, such as propylene ethylene random copolymers, are not known.

[0006] Attempts have been made to reduce the sealing initiation temperature of propylene ethylene random copolymers by adding elastomers or plastomers. The shortcoming of this method is that efficiency is limited and still better results are obtained by utilizing terpolymers. It has been proven that efficiency also depends on process parameters to a great extent, such as the type of equipment used and the composition of the production line. These difficulties have all been observed for unoriented films and oriented films such as bidirectional polypropylene (BOPP) films.

[0007] Furthermore, after the addition of elastomers or plastomers, not only is it difficult to reduce the seal initiation temperature, but other important properties such as optical properties and hot tack are often degraded. In order to achieve an acceptable reduction in the seal initiation temperature, it is usually necessary to add much more than 10% by weight of the elastomer or plastomer. This results in very high costs and / or feeding difficulties in the converter.

[0008]

[0006] Therefore, there remains a need for improved and economical polyolefin compositions that provide reduced seal initiation temperatures without compromising other important properties such as optics and hot tack.

[0009] Therefore, an object of the present invention is to overcome the drawbacks of the prior art.

[0010] The present invention is based on the finding that said object can be achieved by providing a polyol as further defined below comprising propylene and one or more selected from ethylene and C4-C 12 A polyolefin composition comprising a random copolymer of propylene and a polymer of 1-butene is provided.

[0011] Therefore, the present invention relates in one aspect to a polyolefin composition comprising

[0012] (A) propylene and one or more selected from ethylene and C4-C 12 - a random copolymer of propylene (R-PP) containing monomers of α-olefins, having

[0013] - a comonomer content of 1.0 to 10 wt.-%, based on the weight of the random propylene copolymer (R-PP), and

[0014] (B) a polymer of 1-butene having

[0015] - Weight average molecular weight M from 100,000 to 300,000 g / mol w ,and

[0016] - Molecular weight distribution M below 6.0 w / M n .

[0017] Polyolefin compositions according to the present invention provide improved (i.e. reduced) seal initiation temperature without deteriorating other important properties of the polyolefin compositions such as optical properties and hot tack. Preferably, polyolefin compositions of the present invention also provide industrially feasible and economical solutions, i.e. can achieve avoiding the use of expensive terpolymers or copolymers comprising a large amount of expensive additives.

[0018] The term "random" indicates that the comonomers of the random propylene copolymer (R-PP) are randomly distributed within the propylene copolymer. The term random is understood according to IUPAC (Glossary of Basic Terms in Polymer Science; IUPAC Recommendations 1996).

[0019] Thus the random propylene copolymer (R-PP) comprises a xylene insoluble fraction, i.e. a xylene cold insoluble (XCU) fraction, in an amount of at least 80 wt.-%, still more preferably at least 85 wt.-% and most preferably at least 90 wt.-%, based on the total amount of the random propylene copolymer (R-PP).

[0020] Thus, the xylene cold solubles (XCS) content of the random propylene copolymer (R-PP) is below 20 wt.%, more preferably below 15 wt.%, still more preferably below 10 wt.%, such as in the range of 2.0 to 8.0 wt.%. The XCS content is typically at least 0.5 wt.%. The weight percentages are based on the total weight of the random propylene copolymer (R-PP).

[0021] As known to the skilled person, random copolymers are different from heterophasic polypropylenes. Typically, heterophasic polypropylenes are propylene copolymers comprising a propylene homopolymer or random copolymer matrix component (1) and an elastomeric copolymer component (2) of propylene with one or more of ethylene and C4-C8-olefin comonomers, wherein the elastomeric (non-crystalline) copolymer component (2) is dispersed in the propylene homopolymer or random copolymer matrix polymer (1). The presence of the elastomeric phase or the presence of so-called inclusions is visible, for example, by high-resolution microscopy, such as electron microscopy or atomic force microscopy. Random copolymers do not contain an elastomeric polymer phase dispersed therein.

[0022] Thus, the term "random propylene copolymer" according to the present invention excludes all multiphase systems. In other words, the random propylene copolymer (R-PP) does not comprise an elastomeric phase. Thus, the random propylene copolymer (R-PP) is monophasic.

[0023] As indicated above, the presence of second phases or so-called inclusions is visible, for example, by high-resolution microscopy such as electron microscopy or atomic force microscopy, but also by dynamic mechanical thermal analysis (DMTA). Specifically, in DMTA, the presence of a multiphase structure can be determined by the presence of at least two different glass transition temperatures.

[0024] Accordingly it is preferred that the random propylene copolymer (R-PP) does not have a glass transition temperature below -30 °C, preferably below -25 °C, more preferably below -20 °C.

[0025] The random propylene copolymer (R-PP) may be any commercially available polymer that meets the above requirements. The random propylene copolymer (R-PP) may be produced using conventional catalyst systems such as Ziegler-Natta catalysts or single-site catalysts such as metallocene catalysts.

[0026] As indicated above, the random propylene copolymer (R-PP) has a comonomer content in the range of 1.0 to 10 wt%. Preferably, the random propylene copolymer (R-PP) has a comonomer content of at least 1.6 wt%, more preferably at least 2.0 wt%, still more preferably at least 3.0 wt%, further preferably at least 4.0 wt%. The preferred range of comonomer content can be, for example, 2.0 to 10 wt% or 3.0 to 10 wt%, preferably 3.0 to 8.3 wt%, further preferably 3.5 to 8.0 wt%, even further preferably 4.0 to 6.0 wt%. It is further preferred that the comonomer content is not higher than 8.3 wt%, more preferably not higher than 6.0 wt%. The weight percentage is based on the gross weight of the random propylene copolymer (R-PP).

[0027] The random propylene copolymer (R-PP) preferably has a melt flow rate MFR2 as measured according to ISO 1133 at 230°C (2.16 kg) of 1.0 to 50 g / 10 min, more preferably 5.0 to 15 g / 10 min, even more preferably 5.0 to 11 g / 10 min.

[0028] The random propylene copolymer (R-PP) preferably exhibits two melting temperatures T 20 different from each other as determined by differential scanning calorimetry according to ISO 11357-3. m .

[0029] Preferably, the two melting temperatures T of the random propylene copolymer (R-PP) are m They differ from each other by at least 4.0°C, more preferably by 5.0 to 40°C, even more preferably by 5.0 to 20°C, still more preferably by 5.0 to 15°C.

[0030] For example, a higher melting temperature (T m ) may be in the range of 142 to 165°C, preferably 142 to 155°C, more preferably 146 to 152°C.

[0031] For example, a lower melting temperature (T m ) may be in the range of 125 to below 141°C, preferably 130 to below 141°C, more preferably 137 to 141°C.

[0032] It is believed that the bimodal melting temperature (Tm ) arise from two different populations of crystallites within the propylene random copolymer (R-PP).

[0033] In an especially preferred embodiment of the present invention the random propylene copolymer (R-PP) is a random propylene ethylene copolymer (R-PP), i.e. the comonomer is ethylene and only one comonomer is present.

[0034] Thus, the term "propylene ethylene random copolymer" means that the copolymer consists of only two monomer units, namely propylene and ethylene units. In other words, the propylene ethylene random copolymer (R-PP) does not contain additional comonomers and therefore does not include terpolymers.

[0035] As indicated above, the comonomer content of the propylene random copolymer (R-PP) is in the range of 1.0 to 10 wt%, i.e., the ethylene content of the preferred propylene ethylene random copolymer (R-PP) is in the range of 1.0 to 10 wt%. It is preferred herein that the ethylene content of the propylene ethylene random copolymer (R-PP) is at least 1.6 wt%, more preferably at least 2.0 wt%, still more preferably at least 3.0 wt%. The preferred range of ethylene content is the range of 3.0 to 10 wt%. It is further preferred that the ethylene content is not higher than 8.3 wt%, more preferably not higher than 6.0 wt%. The weight percentage is based on the gross weight of the propylene ethylene random copolymer (R-PP).

[0036] In a preferred embodiment, the propylene ethylene random copolymer (R-PP) comprises a propylene ethylene random copolymer fraction (R-PP1) and a propylene ethylene random copolymer fraction (R-PP2) in a weight ratio [(R-PP1) / (R-PP2)] of 30 / 70 to 70 / 30, wherein the ethylene content of the propylene ethylene random copolymer fraction (R-PP1) is the same as or different from the ethylene content of the propylene ethylene random copolymer fraction (R-PP2), preferably different.

[0037] Therefore, in a preferred embodiment of the present invention, the propylene ethylene random copolymer (R-PP) comprises, preferably comprises only as polymer components, more preferably consists of only as polymer components, 30 to 70 wt% of R-PP1, preferably 30 to 60 wt% of R-PP1, more preferably 40 to 50 wt% of R-PP1, and 30 to 70 wt% of R-PP2, preferably 40 to 70 wt%, more preferably 50 to 60 wt% of R-PP2.

[0038] The melt flow rate MFR2 of the two fractions R-PP1 and R-PP2, as measured according to ISO 1133 at 230°C (2.16 kg), may be approximately the same or may differ, such as by 0.1 to 5.0 g / 10 min or by 0.1 to 3.0 g / 10 min.

[0039] The ethylene content of the two fractions R-PP1 and R-PP2 may be substantially the same or may be different. Preferably, the ethylene content of the two fractions R-PP1 and R-PP2 differs by 0 to 5 wt%. For example, the ethylene content of the propylene ethylene random copolymer fraction (R-PP1) differs from the ethylene content of the propylene ethylene random copolymer fraction (R-PP2) in the range of 0 to 2.55 wt%, or preferably in the range of 0 to 1.45 wt%, or preferably in the range of 0.36 to 1.45 wt%.

[0040] In a preferred embodiment, one fraction R-PP1 has an ethylene content in the range of 1.0 to 8.0 wt.-%, more preferably in the range of 1.0 to 6.0 wt.-%, even more preferably in the range of 1.6 to 4.0 wt.-%, based on the weight of R-PP1. Then, the other fraction R-PP2 has an ethylene content in the range of 1.0 to 10 wt.-%, more preferably in the range of 1.0 to 8.0 wt.-%, even more preferably in the range of 1.6 to 6.0 wt.-%, based on the weight of R-PP2.

[0041] In a preferred embodiment, the xylene cold solubles (XCS) content of the propylene ethylene random copolymer fraction (PP1) with lower ethylene comonomer content is preferably equal to or lower than 10 wt.-%, more preferably equal to or lower than 8.0 wt.-%, such as in the range of 2.0 to 8.0 wt.-%, such as in the range of 2.8 to 6.0 wt.-%. The XCS content will typically be at least 0.5 wt.-%. The weight percentages are based on the total weight of the propylene ethylene random copolymer fraction (PP1).

[0042] In a preferred embodiment, the xylene cold solubles (XCS) content of the propylene ethylene random copolymer fraction (R-PP2) is preferably equal to or lower than 12 wt%, such as in the range of 2.0 to 12 wt%, such as in the range of 2.8 to 11.5 wt%, for example in the range of 3.5 to 9.0 wt%. The XCS content will typically be at least 0.5 wt%. The weight percentages are based on the total weight of the propylene ethylene random copolymer fraction (R-PP2).

[0043] In a preferred embodiment the random propylene copolymer (R-PP) is non-visbroken. As known to the person skilled in the art, visbreaking can be achieved e.g. by using peroxides.

[0044] As already indicated above, the polyolefin composition according to the present invention comprises a polymer of 1-butene.

[0045] The polymer of 1-butene according to the present invention has a weight average molecular weight M w It is 100,000 to 300,000 g / mol, preferably 150,000 to 250,000 g / mol, and more preferably 175,000 to 225,000 g / mol.

[0046] The polymer of 1-butene according to the present invention has a molecular weight distribution M w / M n The molecular weight distribution M is less than 6.0, preferably less than 4.5, and more preferably less than 3.5. w / M n The molecular weight distribution as used herein is the weight average molecular weight M w and number average molecular weight M n ratio.

[0047] The polymer of 1-butene according to the invention preferably has a melt flow rate MFR2 of at least 1 g / 10 min, more preferably at least 2 g / 10 min, even more preferably at least 3 g / 10 min, as measured at 190° C. (2.16 kg) according to ISO 1133. The polymer of 1-butene according to the invention will generally have a melt flow rate MFR2 of 10 g / 10 min or less, such as 8 g / 10 min or less, or 6 g / 10 min or less, as measured at 190° C. (2.16 kg) according to ISO 1133. The polymer of 1-butene according to the invention may for example have a melt flow rate MFR2 of 2.0 g / 10 min to 10 g / 10 min, preferably 2.5 g / 10 min to 8.0 g / 10 min, further preferably 3.0 to 6.0 g / 10 min, as measured at 190° C. (2.16 kg) according to ISO 1133.

[0048] The polymer of 1-butene according to the present invention may be a homopolymer of 1-butene or preferably a copolymer of 1-butene and one or more comonomers (preferably selected from ethylene and C3-C4 12-α-olefin), especially preferably a copolymer of 1-butene and ethylene or propylene, and further preferably a copolymer of 1-butene and ethylene. The polymer of 1-butene according to the present invention can be preferably, for example, a copolymer of 1-butene and one or more comonomers, so that the content of 1-butene is, for example, 1% by weight to <50% by weight, preferably 10% by weight to 40% by weight, and further preferably 20% by weight to 35% by weight, based on the weight of the copolymer. The polymer of 1-butene according to the present invention can further be, for example, a copolymer of 1-butene and ethylene or propylene, so that the content of 1-butene is, for example, 1% by weight to <50% by weight, preferably 10% by weight to 40% by weight, and further preferably 20% by weight to 35% by weight, based on the weight of the copolymer. The polymer of 1-butene according to the present invention can be, for example, a copolymer of 1-butene and ethylene, so that the content of 1-butene is, for example, 1% by weight to <50% by weight, preferably 10% by weight to 40% by weight, and further preferably 20% by weight to 35% by weight, based on the weight of the copolymer.

[0049] Such 1-butene polymers according to the present invention may be commercially available products, such as TAFMER BL2491M available from Mitsui, or may be produced in a conventional manner using conventional polymerization processes and polymerization reactors described in the polymer literature. The choice of process conditions is within the technical knowledge of the skilled person.

[0050] The sum of the random propylene copolymer (R-PP) and the polymer of 1-butene constitutes the main part of the polyolefin composition of the present invention. Therefore, preferably, based on the gross weight of the polyolefin composition of the present invention, the amount of the sum of the random propylene copolymer (R-PP) and the polymer of 1-butene is at least 80 wt %, more preferably at least 90 wt %, still more preferably at least 95 wt %. The remainder up to 100 wt % is preferably an additive as defined in more detail below.

[0051] It is preferred that the polyolefin composition of the present invention does not contain any further polymeric material besides the random propylene copolymer (R-PP) and the polymer of 1-butene.

[0052] As used herein, "polymeric material" does not include any carrier polymers for optional additives, such as additives optionally present in the polyolefin composition and masterbatches of carrier polymers. Such optional carrier polymers are calculated as the amount of the corresponding additive based on the amount of the polyolefin composition (100%). Therefore, polymers that are part of an additive mixture, such as carrier polymers in a masterbatch, are excluded from the definition of "polymeric material".

[0053] Taking into account the absolute and relative amounts of the random propylene copolymer (R-PP) and the polymer of 1-butene in the polyolefin composition of the present invention, the following preferred ranges apply.

[0054] Based on the weight of the polyolefin composition of the present invention, the amount of the random propylene copolymer (R-PP) is preferably at least 80 wt%, more preferably at least 85 wt%. Based on the weight of the polyolefin composition of the present invention, the amount of the random propylene copolymer (R-PP) is generally at most 98 wt%. Based on the weight of the polyolefin composition of the present invention, the amount of the random propylene copolymer (R-PP) can be, for example, 80 wt% to 99 wt%, preferably 85 wt% to 98 wt%, more preferably 85 wt% to 95 wt%, more preferably 88 wt% to 93 wt%.

[0055] The amount of polymer of 1-butene is preferably at least 1.0 wt%, more preferably at least 5.0 wt%, still more preferably at least 7.0 wt%, based on the weight of the polyolefin composition of the present invention.

[0056] The amount of polymer of 1-butene is generally at most 20 wt%, preferably at most 15 wt%, more preferably at most 12 wt%, based on the weight of the polyolefin composition of the present invention.

[0057] Therefore, the particularly preferred range of the amount of the polymer of 1-butene in the polyolefin composition of the present invention may be 1.0 to 20 wt%, preferably 5.0 to 15 wt%, further preferably 7.0 to 12 wt%, based on the weight of the polyolefin composition of the present invention.

[0058] Additionally or alternatively and preferably, the weight ratio between the polymer of 1-butene and the random propylene copolymer (R-PP) is from 0.01 to 0.25, more preferably from 0.05 to 0.20 and even more preferably from 0.08 to 0.14.

[0059] Since it is believed that according to a preferred embodiment of the present invention the bimodal melting temperature (T m ) arise from two different crystallite populations within the random propylene copolymer (R-PP), so preferably, the random propylene copolymer (R-PP) is obtainable by a continuous polymerization process comprising at least two reactors connected in series, wherein the process comprises the following steps:

[0060] (A) polymerizing propylene and ethylene in a first reactor (R-1), and

[0061] Obtaining the propylene ethylene random copolymer fraction (R-PP1),

[0062] (B) transferring the propylene ethylene random copolymer fraction (R-PP1) and unreacted comonomer from the first reactor to a second reactor (R-2),

[0063] (C) feeding propylene and ethylene into the second reactor (R-2),

[0064] (D) polymerizing propylene and ethylene in the second reactor (R-2) and in the presence of the propylene ethylene random copolymer fraction (R-PP1), and

[0065] The propylene ethylene random copolymer fraction (R-PP2) is obtained, that is, the propylene ethylene random copolymer (R-PP) comprises a propylene ethylene random copolymer fraction (R-PP1) and a propylene ethylene random copolymer fraction (R-PP2),

[0066] Further,

[0067] (i) the temperature in the first reactor (R-1) is preferably higher than 65°C and equal to or lower than 95°C, more preferably higher than 70°C and equal to or lower than 90°C,

[0068] (ii) the temperature in the second reactor (R-2) is preferably 75° C. or higher and 100° C. or lower, more preferably 80° C. or higher and 95° C. or lower,

[0069] (iii) in the first reactor (R-1) and the second reactor (R-2), polymerization is carried out at a temperature of less than 30 m / s as measured according to ASTM D 3662. 2 / g surface area of ​​the solid catalyst system (SCS),

[0070] Further,

[0071] (I) The solid catalyst system (SCS) comprises

[0072] (Ia) a transition metal selected from one of Groups 4 to 6 of the Periodic Table (IUPAC),

[0073] (Ib) a metal selected from one of Groups 1 to 3 of the Periodic Table (IUPAC), and

[0074] (Ic) Internal electron donor (ID).

[0075] Thus, the random propylene copolymer (R-PP) of the present invention is preferably produced in a continuous polymerization process. If the comonomer of the random propylene copolymer (R-PP) is not ethylene, the above preferred processes are also applicable accordingly.

[0076] The term "continuous polymerization process" means that the propylene random copolymer (R-PP) is produced in at least two reactors connected in series. More precisely, the term "continuous polymerization process" means in this article that the polymer of the first reactor (R-1), i.e. the propylene ethylene random copolymer fraction R-PP1, is directly transferred with unreacted comonomer to the second reactor (R-2), in which the propylene ethylene random copolymer fraction R-PP2 is produced. Therefore, the decisive aspect of the process of the present invention is the preparation of the propylene ethylene random copolymer (R-PP) in two different reactors, wherein the reaction material of the first reactor (R-1) is directly transferred to the second reactor (R-2), and the propylene random copolymer (R-PP) thus contains two different fractions, i.e. R-PP1 and R-PP2. Therefore, the process of the present invention comprises at least a first reactor (R-1) and a second reactor (R-2). In a specific embodiment, the process of the present invention consists of two polymerization reactors (R-1) and (R-2). The term "polymerization reactor" shall mean the place where the main polymerization takes place. Therefore, in the case where the process consists of two polymerization reactors, this definition does not exclude the option that the entire process includes a prepolymerization step, for example in a prepolymerization reactor. The term "consisting of" is a closed expression only from the perspective of the main polymerization reactor. In the case of including a prepolymerization reactor, R-PP1 means the sum of the copolymers produced in the prepolymerization reactor and the first polymerization reactor (R-1).

[0077] The first reactor (R-1) is preferably a slurry reactor (SR) and can be any continuous or simple stirred batch tank reactor or loop reactor operating in bulk or slurry. Bulk means polymerization in a reaction medium comprising at least 60 wt.-%, preferably 100 wt.-% monomers. The slurry reactor (SR) is preferably a (bulk) loop reactor (LR).

[0078] The second reactor (R-2) and any subsequent reactors are preferably gas phase reactors (GPR). Such a gas phase reactor (GPR) may be any mechanically mixed or fluidized bed reactor. Preferably, the gas phase reactor (GPR) comprises a mechanically stirred fluidized bed reactor, wherein the gas velocity is at least 0.2 m / sec. Thus, it will be understood that the gas phase reactor is a fluidized bed type reactor, preferably with a mechanical stirring device.

[0079] A preferred multi-stage process is a "loop-gas phase" process, such as that developed by Borealis A / S, Denmark (called technology), as described, for example, in the patent literature, for example in EP 0 887 379 or WO 92 / 12182.

[0080] Preferably in the first reactor (R-1), preferably in the slurry reactor (SR), like in the loop reactor (LR), the temperature is above 65°C, preferably equal to or higher than 68°C, still more preferably in the range of equal to or higher than 65°C to equal to or lower than 95°C, still more preferably in the range of equal to or higher than 65°C to equal to or lower than 90°C, more preferably in the range of 65 to 80°C, and more preferably in the range of 70 to 75°C.

[0081] The pressure in the first reactor (R-1), preferably in the slurry reactor (SR), such as in the loop reactor (LR), is in the range from 25 to 80 bar, preferably from 30 to 70 bar, more preferably from 40 to 60 bar. Hydrogen can be added for controlling the molar mass in a manner known per se.

[0082] Subsequently, the reaction mixture from the first reactor (R-1) is transferred to the second reactor (R-2), i.e. to the gas phase reactor (GPR-1), whereby the temperature in the second reactor (R2) is preferably in the range of equal to or higher than 75°C to 100°C, more preferably in the range of equal to or higher than 80°C to 95°C, more preferably 80 to 90°C.

[0083] Furthermore, it is preferred that in the second reactor (R-2), preferably in the gas phase reactor (GPR-1), the pressure is in the range from 5 bar to 50 bar, preferably from 15 bar to 40 bar, more preferably from 20 to 30 bar. Hydrogen can be added for controlling the molar mass in a manner known per se.

[0084] The residence time can be varied in both reactor zones.

[0085] In a preferred embodiment of the process for the production of the random propylene copolymer (R-PP), the residence time in the bulk reactor, e.g. a loop reactor, is in the range of 0.2 to 4 hours, e.g. 0.3 to 1.5 hours, more preferably in the range of 0.6 to 1.5 hours and the residence time in the gas phase reactor (GPR) will typically be 0.2 to 6.0 hours, such as 0.5 to 4.0 hours, more preferably 1 to 1.9 hours.

[0086] The conditions in the other gas phase reactor (GPR), if present, are similar to the second reactor (R-2).

[0087] In particular, good results can be obtained by the process of the present invention in case the process of the present invention encompasses a prepolymerization (P) before the polymerization in the first reactor (R-1). The prepolymerization (P) can be carried out in the first reactor (R-1), however it is preferred that the prepolymerization (P) takes place in a separate reactor, the so-called prepolymerization reactor (PR). The prepolymerization reactor has smaller dimensions compared to the first (R-1) and second (R-2) reactors, respectively. Preferably, the reaction volume of the prepolymerization reactor (PR) will be 5% to 30% of the reaction volume of the first reactor (R-1), such as a loop reactor. In the prepolymerization reactor (PR), the prepolymerization (P) is carried out in bulk or in slurry as defined above for the first reactor (R-1).

[0088] It should also be understood that the prepolymerization temperature is quite low, i.e. 50°C or below, more preferably 10°C or above to 50°C or below, still more preferably 12 to 45°C, even more preferably 15 to 40°C, such as 18 to 35°C.

[0089] The pressure during the prepolymerization may be from 20 to 80 bar, preferably from 25 to 75 bar, such as from 30 to 70 bar or from 30 to 50 bar. The residence time may be from 0.1 to 1.5 hours, such as from 0.2 to 0.8 hours.

[0090] As indicated above in relation to the general description of preferred polymerization processes, a further preferred aspect of the present invention is the use of specific catalyst systems in the polymerization processes of the present invention.

[0091] The solid catalyst system (SCS) used comprises

[0092] (a) a transition metal selected from Groups 4 to 6 of the Periodic Table (IUPAC), in particular a transition metal from Group 4, preferably Ti,

[0093] (b) a metal selected from Groups 1 to 3 of the Periodic Table (IUPAC), preferably Mg,

[0094] (c) internal electron donor (ID),

[0095] (d) optionally a co-catalyst, such as an aluminum compound, and

[0096] (e) Optional external donors such as organosilane intermetallic compounds, especially hydrocarbyloxysilane compounds.

[0097] The metal is preferably introduced into the solid catalyst system (SCS) as a metal compound (CM) which forms a complex (C) with the internal electron donor (ID) or a precursor thereof (P-ID). The transition metal is further preferably introduced into the solid catalyst system (SCS) as a transition metal compound (CT). Further information in this regard is provided below.

[0098] A notable feature of the preferred catalyst system (SCS) is that it is in solid form. In other words, for the random propylene ethylene copolymer (R-PP) polymerization, heterogeneous catalysis is applied, i.e. the aggregate state (solid state) of the catalyst system (SCS) is different from the aggregate state of the reactants (i.e. propylene and ethylene). Unlike known solid catalyst systems, the catalyst system (SCS) preferably used in the present invention is a so-called self-supported catalyst system, or in other words, the solid catalyst system (SCS) used does not contain a large amount of catalytically inert materials commonly used as carrier materials. The inert carrier material according to the present invention is any material used to reduce the solubility of the catalyst system in the medium commonly used in polymerization processes and in conventional solvents such as pentane, heptane and toluene. Typical inert carrier materials are organic and inorganic carrier materials, such as silica, MgCl2 or porous polymer materials. These carrier materials are generally used in an amount of at least 50% by weight, more preferably at least 70% by weight. Therefore, in the preparation of the solid catalyst system (SCS) preferably used in the present invention, no external support material is used, and therefore the amount of such inert support material within the solid catalyst system (SCS) does not exceed 10.0 wt. %, still more preferably below 5.0 wt. %, still more preferably is undetectable.

[0099] Typically, the solid catalyst system (SCS) has a molecular weight of less than 30 m / s as measured according to the commonly known BET method (ASTM D 3663) using N2 gas as the analytical adsorbent. 2 / g surface area, for example less than 20m 2 In some embodiments, the surface area is more preferably less than 15 m 2 / g, and more preferably less than 10m 2 In some other embodiments, the solid catalyst system exhibits a surface area of ​​5 m 2 / g or less, which is the lowest detection limit in the case of the method used in the present invention.

[0100] The solid catalyst particles (SCS) may additionally or alternatively be defined by a pore volume measured according to ASTM 4641. Thus, it will be appreciated that the solid catalyst particles (SCS) have a pore volume of less than 1.0 ml / g. In some embodiments, the pore volume is more preferably less than 0.5 ml / g, still more preferably less than 0.3 ml / g and even less than 0.2 ml / g. In other preferred embodiments, the pore volume is not detectable when measured according to ASTM 4641.

[0101] Furthermore, the solid catalyst particles (SCS) typically have an average particle size of not more than 500 μm, i.e. preferably in the range of 2 to 500 μm, more preferably 5 to 200 μm. It is particularly preferred that the average particle size is less than 80 μm, still more preferably less than 70 μm. The preferred range of average particle size is 5 to 80 μm, more preferably 10 to 60 μm.

[0102] The solid catalyst system (SCS) is preferably obtainable, i.e. obtained, by a process comprising contacting (a) with (b):

[0103] (a) a solution of a complex (C) of a metal selected from one of Groups 1 to 3 of the Periodic Table (IUPAC) and an internal electron donor (ID), said complex (C) being obtained by reacting a compound (CM) of said metal with said internal electron donor (ID) or a precursor (P-ID) thereof,

[0104] (b) A liquid transition metal compound (CT), or a solution of a transition metal compound (CT).

[0105] An important aspect of the preparation of the preferred solid catalyst system is therefore that the complex (C) and the transition metal compound (CT) are not present in solid form during the preparation of the solid catalyst system (SCS), as this is the case for supported catalyst systems.

[0106] A solution of a complex (C) of a metal selected from one of Groups 1 to 3 of the Periodic Table (IUPAC) and an internal electron donor (ID) is obtained by reacting a compound (CM) of said metal with said internal electron donor (ID) or a precursor (P-ID) thereof in an organic solvent.

[0107] The metal compound (CM) used to prepare the complex (C) may be any metal compound (CM) selected from one of Groups 1 to 3 of the periodic table (IUPAC). However, it is preferred that the complex (C) is a Group 2 metal complex, even more preferably a magnesium complex. Thus, it is understood that the metal compound (CM) used to prepare the complex (C) is a Group 2 metal compound, such as a magnesium compound.

[0108] Therefore, firstly a metal compound (CM) selected from one of Groups 1 to 3 of the periodic table (IUPAC), preferably a Group 2 metal compound, such as selected from magnesium compounds, preferably containing an alkoxy moiety is prepared. More preferably, the metal compound (CM) to be prepared is selected from the group consisting of a Group 2 metal dialkoxide (such as a magnesium dialkoxide), a complex containing a Group 2 metal dihalide (such as a magnesium dihalide) and an alcohol, and a complex containing a Group 2 metal dihalide (such as a magnesium dihalide) and a Group 2 metal dialkoxide (such as a magnesium dialkoxide).

[0109] Thus, the metal compound (CM) selected from one of Groups 1 to 3 of the Periodic Table (IUPAC), preferably a Group 2 metal compound, such as selected from magnesium compounds, is typically titanium-free.

[0110] Most preferably, the magnesium compound is provided by reacting an alkyl magnesium compound and / or a magnesium dihalide with an alcohol. Thus, at least one magnesium compound precursor is reacted with at least one alcohol, the magnesium compound precursor being selected from dialkyl magnesium R2Mg, alkyl magnesium alkoxide RMgOR (wherein each R is the same or different C1 to C 20 alkyl) and magnesium dihalide MgX2 (wherein X is a halogen), the alcohol is selected from the group consisting of a monohydric alcohol R'OH and a polyhydric alcohol R'(OH) m (where R' is C1 to C 20 hydrocarbon group, and m is an integer selected from the group consisting of 2, 3, 4, 5 and 6), to obtain the magnesium compound (CM). R' in the formula R'OH and R'(OH) m The R of the dialkyl magnesium is preferably the same or different C4 to C 12 Alkyl. Typical alkyl magnesium is ethylbutyl magnesium, dibutyl magnesium, dipropyl magnesium, propylbutyl magnesium, dipentyl magnesium, butylpentyl magnesium, butyloctyl magnesium and dioctyl magnesium. Typical alkyl-alkoxy magnesium compounds are ethylbutoxy magnesium, dibutoxy magnesium, butylpentyl magnesium, dipentyl magnesium, octylbutoxy magnesium and octyloctyl magnesium. Most preferably, one R of R2Mg is butyl and the other R is octyl, i.e. the dialkyl magnesium compound is butyloctyl magnesium.

[0111] The alcohol used in the reaction with the magnesium compound precursor as described in the previous paragraph is a monohydric alcohol (typically C1 to C 20 The magnesium-rich complex can be obtained by replacing a portion of the monohydric alcohol with a polyol. In one embodiment, it is preferred to use only one monohydric alcohol.

[0112] Preferred monohydric alcohols are those of the formula R'OH, wherein R' is C2 to C 16Alkyl, most preferably C4 to C 12 Alkyl, such as 2-ethyl-1-hexanol.

[0113] Typical polyols are ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, pinacol, diethylene glycol, triethylene glycol, glycerol, trimethylolpropane and pentaerythritol. Most preferably, the polyol is selected from the group consisting of ethylene glycol, 2-butyl-2-ethyl-1,3-propanediol and glycerol.

[0114] The reaction conditions for obtaining a metal compound (CM) selected from one of Groups 1 to 3 of the Periodic Table (IUPAC), preferably a metal compound (CM) of Group 2, even more preferably a magnesium compound, may vary depending on the reactants and reagents used. However, according to a preferred embodiment of the present invention, the magnesium compound precursor is reacted with the at least one alcohol at a temperature of 30 to 80° C. for 10 to 90 min, preferably about 30 min.

[0115] After having obtained a metal compound (CM) selected from one of the groups 1 to 3 of the periodic table (IUPAC), preferably a metal compound (CM) of group 2, even more preferably a magnesium compound, said compound (CM) is further reacted with an internal electron donor (ID) or an electron donor precursor (P-ID). The internal electron donor (ID) is preferably a monoester or diester of a carboxylic acid or a diacid, said carboxylic acid or diacid being able to form a complex with a chelate-like structure, preferably a monoester or diester of an aromatic carboxylic acid or diacid. The carboxylic acid ester or diester, preferably a monoester or diester of an aromatic carboxylic acid or diacid, can be reacted by reacting a carboxylic acid halide or a diacid halide (i.e. a preferred internal electron donor precursor (P-ID)) with a C2-C 16 The metal compound (CM) is preferably reacted with an internal electron donor precursor (P-ID), ie with a dicarboxylic acid dihalide preferably having the following formula (I), to obtain the complex (C),

[0116]

[0117] in

[0118] Each R" is the same or different from C1 to C 20 The hydrocarbon group or two R" together with the two unsaturated carbons seen in formula (I) form a C5 to C 20 aliphatic or aromatic ring, and

[0119] X' is a halogen.

[0120] Among the non-aromatic dicarboxylic acid dihalides, the group consisting of maleic acid dihalides, fumaric acid dihalides and their respective R"-substituted derivatives such as citraconic acid dihalides and mesaconic acid (methylfumaric acid) dihalides is the most important.

[0121] Among the cyclic (preferably aromatic) dicarboxylic acid dihalides, the group consisting of phthalic acid dihalides (1,2-benzenedicarboxylic acid dihalides), its hydrogenated 1,2-cyclohexanedicarboxylic acid dihalides and their derivatives is of the greatest importance. Most preferably, the dicarboxylic acid dihalide is phthaloyl dichloride.

[0122] Preferably, the magnesium compound and the dicarboxylic acid halide are mixed at a molar ratio of Mg 添加的总量 The ratio of the carbonyl group to dicarboxylic acid halide is 1:1 to 1:0.1, preferably 1:0.6 to 1:0.25.

[0123] Preferably, a metal compound (CM) selected from one of Groups 1 to 3 of the Periodic Table (IUPAC), more preferably a metal compound of Group 2, even more preferably a magnesium compound, is reacted with an internal electron donor (ID) or with an internal electron donor precursor (P-ID), i.e. a dicarboxylic acid dihalide, under at least one of the following conditions:

[0124] - adding the dicarboxylic acid dihalide at room temperature, and

[0125] - heating the obtained reaction mixture to a temperature of 20 to 80°C, preferably 50 to 70°C

[0126] - The temperature is maintained for 10 to 90 min, preferably 25 to 35 min.

[0127] The organic solvent used to prepare the complex (C) may be any organic solvent as long as it ensures that the complex (C) dissolves at ambient temperature, i.e., at a temperature up to 80° C. (20 to 80° C.). 10 Hydrocarbons, more preferably C6 to C 10 Aromatic hydrocarbons such as toluene, preferably C5 to C 10 Hydrocarbons, more preferably C6 to C 10 Aromatic hydrocarbons such as toluene.

[0128] Suitable transition metal compounds (CT) are in particular transition metal compounds (CT) of transition metals of groups 4 to 6 of the periodic table (IUPAC), in particular of group 4 or 5. Suitable examples include Ti and V, particularly preferred are compounds of Ti, such as TiCl4.

[0129] In addition to the above compounds, the solid catalyst system (SCS) may also contain, for example, a reducing agent, such as a compound of Group 13, preferably an Al-compound containing an alkyl and / or alkoxy group and optionally a halogen group. These compounds may be added to the solid catalyst system (SCS) preparation at any step before final recovery.

[0130] In addition to the catalyst components, the solid catalyst system (SCS) preferably used in the present invention may also contain conventional cocatalysts, for example those based on compounds of Group 13 of the Periodic Table (IUPAC) may be mentioned, for example organoaluminum, such as aluminum compounds, such as alkylaluminum, aluminum halides or alkylaluminum halide compounds (for example triethylaluminum) compounds.

[0131] Additionally, one or more external donors may be used, which may be typically selected, for example, from silanes or any other external donors known in the art. External donors are known in the art and are used as stereoregulating agents in propylene polymerization. The external donor is preferably selected from diethylamino-triethoxy-silane (U-donor), hydrocarbyloxysilane compounds and hydrocarbyloxyalkane compounds.

[0132] Typical hydrocarbyloxysilane compounds have the formula (II)

[0133] R'0Si(OR") 4-0 (II)

[0134] in

[0135] R' is an a- or b-branched C3 to C 12 - a hydrocarbon group,

[0136] R" is C1 to C 12 - a hydrocarbon group, and

[0137] 0 is an integer from 1 to 3.

[0138] More specific examples of hydrocarbyloxysilane compounds that can be used as external electron donors in the present invention are diphenyldimethoxysilane, dicyclopentyldimethoxysilane (D-donor), dicyclopentyldiethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentylmethyldiethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, cyclohexylmethyldimethoxysilane (C-donor), cyclohexylmethyldiethoxysilane, methylphenyldimethoxysilane, diphenyldiethoxysilane, cyclopentyltrimethoxysilane, phenyltrimethoxysilane, cyclopentyltriethoxysilane, phenyltriethoxysilane. Most preferably, the organosilane compound is diethylamino-triethoxy-silane (U-donor), cyclohexylmethyldimethoxysilane (C-donor) or dicyclopentyldimethoxysilane (D-donor), the latter being particularly preferred.

[0139] After contacting the solution of the complex (C) with the liquid of the transition metal compound (CT) or the solution of the transition metal compound (CT), the solid catalyst system (SCS) will precipitate spontaneously or, alternatively, form an emulsion, the latter being preferred. Whether an emulsion is obtained or immediate precipitation occurs depends on the specific conditions chosen. Reference is made in particular to international patent applications WO 03 / 000754, WO 03 / 000757 and WO 2007 / 077027 and to European patent application EP 2 251361. The emulsion process is described in more detail hereinafter.

[0140] The solid catalyst system according to the emulsion method is obtained by:

[0141] (a) preparing a solution of a complex (C) of a metal selected from one of Groups 1 to 3 of the Periodic Table (IUPAC) and an internal electron donor (ID), said complex (C) being obtained by reacting a compound (CM) of said metal with said internal electron donor (ID) or a precursor thereof (P-ID) in an organic solvent,

[0142] (b) mixing a solution of the complex (C) with a liquid transition metal compound (CT),

[0143] (c) thereby obtaining an emulsion of a continuous phase and a dispersed phase, the dispersed phase being in the form of droplets and comprising the complex (C) and the transition metal compound (CT),

[0144] (d) solidifying the droplets of the dispersed phase to obtain a solid catalyst system (SCS).

[0145] Therefore, for the emulsion method, it is preferred to dissolve the complex (C) in a C6 to C 10 Aromatic hydrocarbons (such as toluene), and in contact with a liquid transition metal compound (CT), preferably a liquid transition metal compound (CT) of transition metals of Groups 4 to 6 of the Periodic Table (IUPAC), especially Group 4, such as Ti (e.g. TiCl4). Due to the contact of the solution of the complex (C) with the liquid transition metal compound (CT), an emulsion is formed. The contact is carried out at low temperatures, especially at a temperature above 10°C but below 60°C, preferably at a temperature above 20°C to below 50°C, to promote the generation of two phases (i.e., emulsion). The emulsion comprises a continuous phase and a dispersed phase in the form of droplets. In the dispersed phase, there are complexes (C) and transition metal compounds (CT).

[0146] Can be at any step before final recovery solid catalyst system, other catalyst component, such as aluminum compound, such as alkyl aluminum, alkyl aluminum halide or alkoxy aluminum or alkoxy alkyl aluminum or aluminum halide, or other compound that serves as reducing agent is added in reaction mixture.In addition, during preparation, can add any reagent that strengthens emulsion formation.As an example, can mention emulsifier or emulsion stabilizer, such as surfactant, such as acrylic acid or methacrylic acid polymer solution and turbulence minimizing agent, such as alpha-olefin polymer without polar group, such as polymer of alpha-olefin of 6 to 20 carbon atoms.

[0147] Suitable methods for mixing the obtained emulsion include mixing using machinery as well as using ultrasound as known to the skilled person. Process parameters, such as the time of mixing, the intensity of mixing, the type of mixing, the power used for mixing (such as mixer speed or the wavelength of ultrasound used), the viscosity of the solvent phase, the additives used (such as surfactants), etc., are used to adjust the size of the solid catalyst system (SCS) particles.

[0148] The solid catalyst system (SCS) particles can then be formed and recovered in a conventional manner, including solidification of the catalyst particles by heating (e.g. at a temperature of 70 to 150° C., more preferably at a temperature of 90 to 110° C.) and a separation step (for recovering the catalyst particles). In this regard, reference is made to the disclosure in International Applications WO 03 / 000754, WO 03 / 000757, WO 2007 / 077027, WO 2004 / 029112 and WO 2007 / 077027 which disclose suitable reaction conditions. This disclosure is incorporated herein by reference. The obtained solid catalyst particles (SCS) may also be subjected to further post-treatment steps, such as washing, stabilization, prepolymerization, before final use in a polymerization process.

[0149] In a preferred embodiment of the preparation of the catalyst, the solid catalyst component is prepared by the following method, which comprises: reacting an alkoxy magnesium compound with an electron donor or a precursor thereof in a C6-C 10The invention relates to a method for preparing a solution of a magnesium complex by reacting the magnesium complex with at least one compound of a tetravalent Group 4 metal at a temperature greater than 10°C and less than 60°C to produce an emulsion having a dense, TiC14 / toluene-insoluble oil dispersed phase, the emulsion having a Group 4 metal / Mg molar ratio in the oil dispersed phase of 0.1 to 10, the oil dispersed phase having a Group 4 metal / Mg molar ratio of 10 to 100; stirring the emulsion, optionally in the presence of an emulsion stabilizer and / or a turbulence minimizer, to maintain the droplets of the dispersed phase within an average size range of 5 to 200 μm. Catalyst particles are obtained after solidifying the particles of the dispersed phase by heating. In the method, before recovering the final solid particles, or during a washing step of the solidified particles, a catalyst of the formula AlR is added. 3-n X n An alkylaluminum compound of 1 to 20, preferably 1 to 10, carbon atoms is prepared and brought into contact with the droplets of the dispersed phase of the stirred emulsion, wherein R is an alkyl and / or alkoxy group having 1 to 20, preferably 1 to 10 carbon atoms, X is a halogen and n is 0, 1, 2 or 3. The alkylaluminum compound is preferably a trialkylaluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum or tri-n-octylaluminum. However, it may also be an alkylaluminum halide such as diethylaluminum chloride, dimethylaluminum chloride and ethylaluminum sesquichloride.

[0150] Typical examples used as external donors are dicyclopentyldimethoxysilane (DCPDMS), cyclohexylmethyl-dimethoxysilane (CHMDMS) and dicyclopentadienyldiethoxysilane (DCPDES).

[0151] The polyolefin composition according to the present invention may further comprise additives.

[0152] The polyolefin composition may contain additives known in the art, such as antioxidants, acid scavengers, nucleating agents, antiblocking agents and antistatic agents. Typically, the total amount of additives is not higher than 5.0 wt%, still more preferably not higher than 3.0 wt%, such as not higher than 2.0 wt%.

[0153] In one embodiment of the invention, the polyolefin composition comprises 0.1 to 5.0 wt % of one or more additives selected from the group consisting of antiblocking agents (AB), antioxidants, acid scavengers, nucleating agents and antistatic agents. Preferred additives are antiblocking agents, antioxidants and / or acid scavengers.

[0154] Another embodiment preferably contains antiblock agents, antioxidants, and / or acid scavengers, but no slip agents.

[0155] It should be understood that the addition of additives is common in the art. Therefore, it is considered to be disclosed and known to the skilled person that any additive mentioned herein may be added alone or in combination with other additives to the polyolefin composition according to the present invention in the amounts mentioned herein.

[0156] Antioxidants are commonly used in the art, examples being hindered phenols (such as CAS No. 6683-19-8, also marketed by BASF as Irganox 1010FF TM Phosphorus-based antioxidants (such as CAS No. 31570-04-4, also marketed by Clariant as Hostanox PAR 24 (FF) TM Sold or sold by BASF as Irgafos 168 (FF) TM Sold), sulfur-based antioxidants (such as CAS No. 693-36-7, sold by BASF as Irganox PS-802FL TM (sold by ), nitrogen-based antioxidants (such as 4,4'-bis(1,1'-dimethylbenzyl)diphenylamine), or antioxidant blends.

[0157] Acid scavengers are also well known in the art. Examples are calcium stearate, sodium stearate, zinc stearate, magnesium and zinc oxide, synthetic hydrotalcite (eg SHT, CAS-No. 11097-59-9), lactates and esters of lactylate and calcium and zinc stearate.

[0158] Common anti-adhesive agents are natural silica such as diatomaceous earth (such as CAS-no.60676-86-0 (SuperfFloss TM ), CAS-no.60676-86-0(SuperFloss E TM ) or CAS-no.60676-86-0(Celite 499 TM)), synthetic silica (such as CAS-no.7631-86-9, CAS-no.7631-86-9, CAS-no.7631-86-9, CAS-no.7631-86-9, CAS-no.7631-86-9, CAS-no.7631-86-9, CAS-no.7631-86-9, CAS-no.112926-00-8, CAS-no.7631-86-9, or CAS-no.7631-86-9), silicates (such as aluminum silicate (high kaolin) CAS-no.1318-74-7, sodium aluminum silicate CAS-no.1344-00-9, calcined kaolin CAS-no.92704-41-1, aluminum silicate CAS-no.1327-36-2 or calcium silicate CAS-no.1344-95-2), synthetic zeolite (such as sodium calcium aluminosilicate hydrate CAS-no.1344-01-0, CAS-no.1344-01-0 or sodium calcium aluminosilicate hydrate CAS-no.1344-01-0).

[0159] It is particularly preferred that the anti-blocking agent (AB) is silicon dioxide and / or a silicate. Preferably the anti-blocking agent (AB) is silicon dioxide (SiO2), such as synthetic silicon dioxide. Typically, the silicon dioxide has a pore volume in the range of 0.8 to 1.2 ml / g and / or a particle size of 3.5 to 6.0 μm.

[0160] Nucleating agents are also known in the art. They can be selected from the group consisting of benzoates such as sodium benzoate or lithium benzoate, sorbitol compounds such as 2,4-di(methylbenzylidene)sorbitol, phosphorus-based compounds such as sodium di(4-tert-butylphenol)phosphate, and beta-nucleating agents such as N,N'-dicyclohexyl-2,6-naphthalene dicarboxamide, rosins such as calcium resinates, and the like, such as talc.

[0161] Antistatic agents are also known in the art. They can be selected from the group of: glycerides such as CAS-no.97593-29-8, CAS-no.97593-29-8 or CAS-no.97593-29-8, ethoxylated amines such as Hostastat FA 18 from Clariant TM , ethoxylated amides such as N,N-bis(2-hydroxyethyl)dodecanoamide, permanent antistatic agents such as Irgastat from BASF TM category, or sorbitan-based products such as sorbitan monooleate.

[0162] The present invention in another aspect relates to the use of a polyolefin composition according to the invention as defined above for the preparation of an unoriented or oriented film, preferably an unoriented film, more preferably a cast film.

[0163] Furthermore, the present invention relates in a further aspect to a film, ie an unoriented or oriented film, preferably an unoriented film, more preferably a cast film, comprising the polyolefin composition according to the present invention as defined above.

[0164] Preferably, the film according to the present invention comprises at least 80 wt%, more preferably comprises at least 95 wt%, still more preferably consists of the polyolefin composition according to the present invention as described above.

[0165] An unoriented film is also often referred to as a non-oriented film.

[0166] One can distinguish between unoriented films and oriented films (see for example Handbook of Polypropylene, Nello Pasquini, 2nd edition, Hanser). Oriented films are typically uniaxially or biaxially oriented films, whereas unoriented films are cast, blown or tubular films. Thus, unoriented films are not intentionally (deliberately) stretched in the solid state or close to the solid state in the longitudinal and / or transverse directions as oriented films, i.e., unoriented films in this context mean that the film is not intended to be oriented. Thus, unoriented films are not uniaxially or biaxially oriented films as would be apparent to the skilled person.

[0167] Unoriented films include cast films, tubular quenched films and blown films. Cast films are particularly preferred.

[0168] The oriented film according to the present invention is preferably a biaxially oriented film comprising the polyolefin composition according to the present invention, such as a biaxially oriented polypropylene (BOPP) film.

[0169] The film of the present invention, ie, an unoriented film or an oriented film, preferably a cast film, can be a monolayer or a multilayer film.

[0170] The thickness of the film is not critical but will typically be 20-200 μm.

[0171] The monolayer film of the present invention comprises at least 80% by weight, preferably at least 95% by weight, of the polyolefin composition of the present invention, preferably consists of the polyolefin composition of the present invention.

[0172] The thickness of the single-layer film of the present invention is typically 20-200 μm, suitably 20-100 μm.

[0173] The multilayer film of the present invention comprises at least one layer comprising the inventive polyolefin composition as defined above. Said layer of the multilayer film comprising the polyolefin composition according to the present invention as described above may be any layer(s), such as a core layer or an outer layer.

[0174] According to a particularly preferred embodiment, the multilayer film of the present invention comprises at least one layer comprising the inventive polyolefin composition as defined above as outer layer, more preferably as sealant layer, and at least one, preferably two further film layers.

[0175] The multilayer film according to this particularly preferred embodiment of the invention may be a cast film or a BOPP film, preferably a cast film.

[0176] In this respect, it is more preferred that the multilayer cast film or BOPP film of the present invention, preferably the cast film, is a film comprising at least three layers, even more preferably a film consisting of at least three layers, wherein one outer layer is a sealant layer comprising the polyolefin composition of the present invention as defined above, even more preferably a sealant layer consisting of the polyolefin composition of the present invention as defined above, and wherein the multilayer film further comprises a core layer, preferably comprising a propylene homopolymer, and wherein the multilayer film further comprises a second outer layer, the second outer layer being a non-sealable skin layer, preferably comprising a propylene random copolymer. Most preferably, in this embodiment, the multilayer film is a cast film of at least three layers, preferably consisting of three layers as described above.

[0177] In this respect, in a further embodiment, the multilayer cast film or BOPP film of the present invention, preferably cast film, is a film comprising more than three layers, preferably at least five layers, even more preferably a film consisting of more than three layers, preferably at least five layers, wherein one outer layer is a sealant layer comprising the polyolefin composition of the present invention as defined above, even more preferably a sealant layer consisting of a composition comprising the polyolefin composition of the present invention as defined above, and wherein the multilayer film further comprises a core layer, preferably comprising a propylene homopolymer, and wherein the multilayer film further comprises a second outer layer, which is a non-sealable skin layer, preferably comprising a propylene random copolymer, and wherein the multilayer film further comprises two so-called subskin layers, one of which is between the core layer mentioned above and the non-sealable skin layer, and the other subskin layer is between the core layer mentioned above and the sealant layer. Most preferably, in this embodiment, the multilayer film is a cast film of at least five layers, preferably a cast film of five layers as defined above.

[0178] The thickness of the layer of multilayer film (each layer comprises the polyolefin composition according to the present invention as described) can be between 1-200 μm, suitably change between 1-190 μm, this depends on the function of this layer, i.e. whether this layer works as outer layer (skin layer) or as core layer, and selects accordingly as known to those skilled in the art. For example, the thickness that outer layer has can be 2-8 μm, and the thickness of core layer can be for example 14-200 μm, as 16-100 μm.

[0179] At least one layer of the multilayer film of the present invention comprises, preferably consists of, at least 80% by weight, preferably at least 95% by weight, of the polyolefin composition of the present invention.

[0180] The film of the present invention, preferably an unoriented film, more preferably a cast film, is preferably transparent.

[0181] The films of the present invention, preferably unoriented films, more preferably cast films, preferably have excellent optical properties, for example, exhibit one, more or all of reduced haze, increased gloss and increased transparency (the amount of light passing through the film), preferably all of the properties.

[0182] The unoriented film, preferably cast film, according to the present invention can be conventionally prepared, as is well known in the art, by extruding the polyolefin composition of the present invention, ie a previously obtained melt mixture thereof, through a die having the dimensions required for the final film application.

[0183] After leaving the die in the extrusion step, the molten film immediately enters a cooling step in which the temperature of the molten film is lowered to solidify the film.

[0184] In a preferred embodiment, the unoriented film, such as a cast film, is obtained by a process comprising the steps of:

[0185] (a) providing a composition for producing a film, comprising components (A) and (B),

[0186] (b) blending the components before or during melt mixing in an extruder for producing the film,

[0187] (c) extruding a film by means of the extruder,

[0188] (d) cooling the obtained film, and

[0189] (e) recovering the obtained thin film.

[0190] In the extrusion step (c), the molten mixture of the polyolefin composition is extruded through a die having the dimensions required for the final film application, as is well known in the art.

[0191] After leaving the die in the extrusion step (c), the molten film immediately enters the cooling step (d), in which the temperature of the molten film is reduced to solidify the film. In the case of cast film, the cooling step (d) of the extruded film is achieved by a cooling roll having a suitable temperature.

[0192] The cast film process is well known to those skilled in the art and is well described in the literature.

[0193] According to an alternative but still preferred embodiment of the present invention, the unoriented film is a blown film and the cooling step (d) carried out on the extruded film is achieved by air.

[0194] According to an alternative but still preferred embodiment of the present invention, the unoriented film is a tubular quenched film and the cooling step (d) carried out on the extruded film is achieved by water.

[0195] The processes for producing blown films with air cooling and for producing tubular quenched films with water cooling are known to the person skilled in the art and are well described in the literature.

[0196] In another aspect, the present invention relates to a random copolymer of propylene and one or more selected from ethylene and C4-C 12 -α-olefins, preferably 1-butene polymers in propylene ethylene random copolymers (R-PP), for reducing the sealing initiation temperature of an oriented or unoriented film, preferably a cast film, comprising the polyolefin composition, the sealing initiation temperature being reduced by at least 5.0°C, preferably by at least 8.0°C, compared to another film which differs only in that the polyolefin composition does not contain 1-butene polymers, wherein

[0197] (A) The random propylene copolymer (R-PP) has

[0198] - a comonomer (ethylene) content of 1.0 to 10 wt.-%, based on the weight of the propylene random copolymer,

[0199] and

[0200] (B) The 1-butene polymer has

[0201] - Weight average molecular weight M from 100,000 to 300,000 g / mol w ,and

[0202] - Molecular weight distribution M below 6.0 w / M n .

[0203] With regard to further preferred embodiments of this aspect of the use of the polymer of 1-butene according to the invention, reference is made to the description of the preferred embodiments of the polyolefin composition according to the invention and the film according to the invention as described above.

[0204] In the following, the present invention is further illustrated by means of examples. Example

[0205] 1. Definition / Measurement Method

[0206] Unless defined otherwise, the following definitions of terms and assay methods apply to the above general description of the invention as well as to the following examples.

[0207] Calculation of the comonomer content of the second propylene ethylene random copolymer fraction (R-PP2):

[0208]

[0209] in

[0210] w(PP1) is the weight fraction (based on the weight of R-PP) of the propylene ethylene random copolymer fraction (R-PP1), i.e. the product of the first reactor (R1),

[0211] w(PP2) is the propylene ethylene random copolymer fraction (R-PP2), i.e. the weight fraction of the polymer produced in the second reactor (R2) (based on the weight of R-PP),

[0212] C(PP1) is the comonomer content [wt%] of the propylene ethylene random copolymer fraction (R-PP1), i.e. the product of the first reactor (R1),

[0213] C(R2) is the comonomer content [wt%] of the product obtained in the second reactor (R2), i.e. the propylene ethylene random copolymer (R-PP),

[0214] C(PP2) is the calculated comonomer content [wt%] of the propylene ethylene random copolymer fraction (R-PP2).

[0215] Calculation of xylene cold soluble (XCS) content of propylene ethylene random copolymer fraction (R-PP2):

[0216]

[0217] in

[0218] w(PP1) is the weight fraction of the propylene ethylene random copolymer fraction (R-PP1), i.e. the product of the first reactor (R1),

[0219] w(PP2) is the weight fraction of the propylene ethylene random copolymer fraction (R-PP2), i.e. the polymer produced in the second reactor (R2),

[0220] XS(PP1) is the xylene cold soluble (XCS) content [wt%] of the propylene ethylene random copolymer fraction (R-PP1), i.e. the product of the first reactor (R1),

[0221] XS(R2) is the xylene cold soluble (XCS) content [% by weight] of the product obtained in the second reactor (R2), i.e. the propylene ethylene random copolymer (R-PP),

[0222] XS(PP2) is the calculated xylene cold soluble (XCS) content of the propylene ethylene random copolymer fraction (R-PP2) [wt. %].

[0223] Calculation of the melt flow rate MFR2 (230°C) of the propylene ethylene random copolymer fraction (R-PP2):

[0224]

[0225] in

[0226] w(PP1) is the weight fraction of the propylene ethylene random copolymer fraction (R-PP1), i.e. the product of the first reactor (R1),

[0227] w(PP2) is the weight fraction of the propylene ethylene random copolymer fraction (R-PP2), i.e. the polymer produced in the second reactor (R2),

[0228] MFR(PP1) is the melt flow rate MFR2 (230°C) [g / 10 min] of the propylene ethylene random copolymer fraction (R-PP1),

[0229] MFR(PP) is the melt flow rate MFR2 (230°C) [g / 10min] of the product obtained in the second reactor (R2), i.e. the propylene ethylene random copolymer (R-PP),

[0230] MFR(PP2) is the calculated melt flow rate MFR2 (230°C) [g / 10min] of the propylene ethylene random copolymer fraction (R-PP2)

[0231] Density was measured according to ISO 1183-1 - Method A (2004). Sample preparation was done by compression molding according to ISO 1872-2:2007.

[0232] MFR2 is measured according to ISO 1133 (2.16 kg load) at 230°C for propylene random copolymers and at 190°C for polymers of 1-butene.

[0233] Ethylene content / comonomer content is calculated using 13 Fourier transform infrared spectroscopy (FTIR) calibrated with C-NMR was used for measurement. When measuring the ethylene content in polypropylene, a thin film (thickness about 0.3 mm) of the sample was prepared by hot pressing. The absorption peaks at 720 and 733 cm were measured using a Bruker Tensor 27 FTIR spectrometer.-1 The area of 13 The method was calibrated based on the presence of ethylene content data from C-NMR. -1 The presence or absence of a comonomer such as ethylene in a polymer of 1-butene can be identified by detecting the additional absorption of ethylene at the position of

[0234] Xylene cold insolubles (XCS, wt. %): The content of xylene cold insolubles (XCS) is determined according to ISO 16152 1st edition 2005-07-01 at 25°C.

[0235] Melting temperature T m , crystallization temperature T c : Measured using Mettler TA820 differential scanning calorimetry (DSC) on 5 to 10 mg samples. DSC was run in a heating / cooling / heating cycle at a scanning rate of 10°C / min in the temperature range of +23 to +210°C according to ISO 11357 / Part 3 / Method C2. The crystallization temperature and enthalpy were determined from the cooling step, while the melting temperature and melting enthalpy were determined from the second heating step.

[0236] Glass transition temperature T g Determined by dynamic mechanical analysis according to ISO 6721-7. 3 ) were measured in torsion mode with a heating rate of 2°C / min and a frequency of 1 Hz.

[0237] Tensile test of thin films: ASTM D882

[0238] Flexural modulus test of base resin or its pellets:

[0239] ISO178. The size of the specimen is 80x 10x 4.0mm 3 (length x width x thickness) and was produced by injection molding according to EN ISO 1873-2. The length of the span between the brackets was 64 mm, the test speed was 2 mm / min and the tensile force was 100 N.

[0240] Number average molecular weight (M n ), weight average molecular weight (M w ) and polydispersity (M w / M n ) was determined by gel permeation chromatography (GPC) according to the following method:

[0241] Weight average molecular weight M w and polydispersity (M w / M n, where Mn is the number average molecular weight and Mw is the weight average molecular weight) is measured by a method based on ISO 16014-1:2003 and ISO 16014-4:2003. At 145 ° C and at a constant flow rate of 1 mL / min, a Waters Alliance GPCV 2000 instrument equipped with a refractive index detector and an online viscometer is used with 3 × TSK-gel columns (GMHXL-HT) from TosoHaas and 1,2,4-trichlorobenzene (TCB, stabilized with 200 mg / L 2,6-di-tert-butyl-4-methyl-phenol as solvent). 216.5 μ L of sample solution was injected for each analysis. The column setting was calibrated using a relative calibration using 19 narrow MWD polystyrene (PS) standards in the range of 0.5 kg / mol to 11 500 kg / mol and a set of well-characterized broad polypropylene standards. All samples were prepared by dissolving 5-10 mg of polymer in 10 mL (at 160° C.) of stabilized TCB (same as mobile phase) and kept under continuous shaking for 3 hours before sampling into the GPC instrument.

[0242] Film thickness is measured according to ISO 4593.

[0243] Transparency, haze and clarity: All optical parameters were measured on 30 μm thick cast films. Transparency, haze and clarity were determined according to ASTM D 1003.

[0244] Gloss was measured to DIN 67530 / ISO 2813 on 30 μm thick cast films at an angle of 60°.

[0245] The seal initiation temperature (SIT) is the seal temperature that produces a heat seal with significant strength (here the seal force is 5 N) measured on an OttoBrugger according to ASTM F 2029 and ASTM F 88 under the following conditions: seal width 25 mm, seal pressure 3 bar, 1 second dwell time, 2 heated flat jaws, seal force 5 N, peel speed 100 mm / s, test speed 250 mm / min.

[0246] Hot tack was measured on a DTC according to ASTM F 1921 under the following conditions: 3 bar, sealing time 1 s, cooling time 0.1 s (release), 2 teflonized jaws, hot tack force 1 N, peel speed 200 mm / s, sealing pressure 0.25 N / mm 2 , dwell / seal time 1 s, delay time 100 ms; test / peel speed 200 mm / s; flat jaws covered with Teflon tape.

[0247] 2. Example

[0248] a) Preparation of propylene ethylene random copolymer (R-PP) according to the present invention:

[0249] The catalyst used in the polymerization process of the examples was the catalyst prepared as in Example 8 of WO 2004 / 029112 A1 (see pages 22-23), except that diethylaluminum chloride was used as the aluminum compound instead of triethylaluminum.

[0250] An external donor, dicyclopentyldimethoxysilane, was used. The ratio of aluminum to donor was 7.5. Polypropylene and ethylene were copolymerized in a pilot bimodal multireactor system for polymerization mode consisting of prepolymerization, loop reactor and gas reactor using the catalyst of the above system and under the polymerization conditions shown in Table 1. Table 2 lists the technical characteristics of the random copolymer of propylene and ethylene obtained.

[0251] In Table 1, "H2 / C3 / mol / kmol" means a feed ratio of H2 / C3, and "C2 / C3 / mol / kmol" means a feed ratio of C2 / C3. The volume of the prepolymerization reactor is very small, and the productivity is much lower than those of the loop reactor and the gas reactor. In this case, R-PP1 means the sum of copolymers as produced in the prepolymerization reactor and the loop reactor, and R-PP2 means a fraction as produced in the gas reactor.

[0252] Table 2 lists the technical characteristics of the final copolymer product and two fractions (R-PP1 and R-PP2) as produced in different reactors. The "C2-content", "XS" and "MFR2" of the 45% fraction (R-PP1) of the final copolymer and the corresponding technical characteristics of the final copolymer are obtained by directly measuring the products of the loop reactor and the gas reactor (i.e. the last reactor), respectively. The "C2-content", "XS" and "MFR2" of the 55% fraction (R-PP2) are obtained by calculation according to the calculation formulas as described in the definitions / measurement methods above.

[0253] Table 1: Polymerization conditions of propylene ethylene random copolymer (R-PP)

[0254]

[0255] Table 2: Technical characteristics of the final propylene ethylene random copolymer (R-PP) and the two fractions as produced in different reactors

[0256]

[0257] b) Preparation of polyolefin composition

[0258] After polymerization, the copolymer is granulated in an extruder. The formulation contains conventional additives such as commonly used acid scavengers (e.g. calcium stearate), antioxidants (e.g. Irganox 1010, Irgafos 168), anti-slip agents and anti-blocking agents (e.g. synthetic silica) in conventionally used amounts.

[0259] In the example of the present invention (Example 2), 10 wt% of Tafmer BL2491M was also added to the polyolefin composition in this step.

[0260] Tafmer BL2491M is a polymer of 1-butene with a weight average molecular weight of 197,000 g / mol as determined by GPC and a molecular weight distribution of w / M n Tafmer BL2491M is commercially available from Mitsui.

[0261] In Reference Example (Example 1), no polymer of 1-butene was added.

[0262] c) Preparation of cast film

[0263] The compositions of Examples 1 and 2 were extruded separately in a casting machine to obtain 30 μm 3-layer films having the following composition.

[0264] Core layer: HD601CF, MFR2 (230°C) is 8.0 g / 10 min and melting temperature T m It is a propylene homopolymer at 164° C. It is commercially available from Borouge / Borealis.

[0265] Non-sealable surface layer: RD265CF, MFR2 (230°C) is 8.0 g / 10 min and melting temperature T m It is a random copolymer of propylene at 151° C. It is commercially available from Borouge / Borealis.

[0266] Sealable skin: COLLIN cast construction as above for the polyolefin composition described in Example 1 (MFR2, 230°C, 2.16 kg, 8.0 g / 10 min) and the polyolefin composition described in Example 2 (MFR2, 230°C, 2.16 kg, 8.1 g / 10 min) for 30 μm 3-layer film (6-18-6 μm)

[0267] Sealable skin on the cold roll side

[0268] No corona treatment

[0269] Table 3 shows the properties of the corresponding cast films of Examples 1 and 2

[0270] Table 3:

[0271]

[0272] As can be seen from the values ​​of Example 2, with the addition of only 10% by weight of the polymer of 1-butene according to the invention, the seal initiation temperature (SIT) is significantly reduced by 8°C. This strong improvement enables a highly viable alternative to high-speed packaging lines with high demands on the selection of polymer materials. In addition, the hot tack is also improved, and the optical properties such as haze and gloss are comparable to the reference, i.e. still very good. The haze is even slightly improved.

Claims

1. A polyolefin composition, comprising (A) propylene and one or more selected from ethylene and C4-C 12 - a random copolymer of propylene containing monomers of α-olefins, which has - a comonomer content of 1.0 to 10 wt.-%, based on the weight of the propylene random copolymer, and (B) a polymer of 1-butene having - Weight average molecular weight M from 100,000 to 300,000 g / mol w ,and - Molecular weight distribution M below 6.0 w / M n .

2. The polyolefin composition according to claim 1, wherein the propylene random copolymer has a xylene cold soluble content of less than 10 wt%.

3. The polyolefin composition according to claim 1 or 2, wherein the random propylene copolymer has a comonomer content of 2.0 to 10 wt% or 3.0 to 10 wt%, preferably 3.0 to 8.3 wt%, more preferably 3.5 to 8.0 wt%, even more preferably 4.0 to 6.0 wt%, based on the weight of the random propylene copolymer.

4. The polyolefin composition according to any one of claims 1 to 3, wherein the comonomer of the propylene random copolymer is ethylene and only one comonomer is present, and / or the polymer of 1-butene is 1-butene with one or more preferably selected from ethylene and / or C3-C 12 - Copolymers of comonomers of α-olefins, whereby the 1-butene content is from 1% to <50% by weight, preferably from 10% to 40% by weight, more preferably from 20% to 35% by weight, based on the weight of the copolymer.

5. The polyolefin composition according to any one of claims 1 to 4, wherein the propylene random copolymer has a melt flow rate MFR2 measured according to ISO 1133 at 230°C (2.16 kg) of 1.0 to 50 g / 10 min, preferably 5.0 to 15 g / 10 min.

6. The polyolefin composition according to any one of claims 1 to 5, wherein the propylene random copolymer exhibits two melting temperatures T 20 different from each other as determined by differential scanning calorimetry according to ISO 11357-3. m .

7. The polyolefin composition according to claim 6, wherein the two melting temperatures T of the propylene random copolymer are m Differ from each other by at least 4.0°C.

8. The polyolefin composition according to any one of claims 1 to 7, wherein the polymer of 1-butene has a melt flow rate MFR2 measured at 190°C (2.16 kg) according to ISO 1133 of 2.0 to 10 g / 10 min or 3.0 to 10 g / 10 min, preferably 2.5 to 8.0 g / 10 min, further preferably 3.0 to 6.0 g / 10 min.

9. The polyolefin composition according to any one of claims 1 to 8, wherein the polymer of 1-butene has a weight average molecular weight M w 150,000 to 250,000 g / mol.

10. The polyolefin composition according to any one of claims 1 to 9, wherein the polymer of 1-butene has a molecular weight distribution M w / M n Below 4.

5.

11. The polyolefin composition according to any one of claims 1 to 10, wherein the amount of the random propylene copolymer is at least 80 wt%, preferably at least 85 wt%, based on the weight of the inventive polyolefin composition, and / or the amount of the polymer of 1-butene is at least 1.0 wt%, preferably at least 5.0 wt%, more preferably at least 7.0 wt%, and the amount of the polymer of 1-butene is at most 15 wt%, preferably at most 12 wt%, and / or the amount of the random propylene copolymer is from 80 to 99 wt%, preferably from 85 to 98 wt%, further preferably from 85 to 95 wt%, further preferably from 88 to 93 wt%, based on the weight of the inventive polyolefin composition, and / or the amount of the polymer of 1-butene is from 1.0 to 20 wt%, preferably from 5.0 to 15 wt%, further preferably from 7.0 to 12 wt%, based on the weight of the inventive polyolefin composition.

12. The polyolefin composition according to any one of claims 1 to 11, wherein the weight ratio between the polymer of 1-butene and the random propylene copolymer is 0.01-0.25, preferably 0.05-0.20, more preferably 0.08-0.

14.

13. A film, preferably an unoriented film or a biaxially oriented film, still more preferably a cast film, comprising the polyolefin composition according to any one of claims 1 to 12.

14. A multilayer film comprising a film according to claim 13 as a sealing layer and at least one, preferably two, further film layers.

15. Use of a polymer of 1-butene in a polyolefin composition for reducing the seal initiation temperature of an oriented or unoriented film comprising the polyolefin composition, the polyolefin composition comprising propylene and one or more selected from ethylene and C4-C 12 - a random copolymer of propylene with monomers of -α-olefins, which reduces the seal initiation temperature by at least 5°C, preferably at least 8°C, compared to another film which differs only in that the polyolefin composition does not contain a polymer of 1-butene, wherein (A) The propylene random copolymer has - a comonomer content of 1.0 to 10 wt.-%, based on the weight of the propylene random copolymer, and (B) The 1-butene polymer has - Weight average molecular weight M from 100,000 to 300,000 g / mol w ,and - Molecular weight distribution M below 6.0 w / M n .

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