阅读说明：本技术 具有零下抗冲击性的聚丙烯共聚物组合物 (Polypropylene copolymer compositions having sub-zero impact resistance ) 是由 约翰·卡莱维·卡托 钟京 阿玛伊娅·蒙托亚-戈尼 于 2020-04-03 设计创作，主要内容包括：本发明公开了聚丙烯聚合物组合物,所述聚丙烯聚合物组合物可被配制为具有优异的清晰度特性连同零下温度处优异的抗冲击特性。所述聚丙烯聚合物组合物是含有与第二相聚合物组合的第一相聚合物的异相组合物。所述第一相聚合物是聚丙烯和α-烯烃共聚物,而所述第二相聚合物也是聚丙烯和α-烯烃无规共聚物。所述第二相聚合物含有相对较高含量的乙烯。发现在所述第二相聚合物中增加乙烯的量显著改善零下温度处的抗冲击性。(Disclosed are polypropylene polymer compositions that can be formulated to have excellent clarity characteristics along with excellent impact resistance characteristics at subzero temperatures. The polypropylene polymer composition is a heterophasic composition comprising a first phase polymer in combination with a second phase polymer. The first phase polymer is a polypropylene and alpha-olefin copolymer and the second phase polymer is also a polypropylene and alpha-olefin random copolymer. The second phase polymer contains a relatively high level of ethylene. It was found that increasing the amount of ethylene in the second phase polymer significantly improved the impact resistance at sub-zero temperatures.)

1. A polypropylene composition, comprising:

a first polymer phase comprising a polypropylene polymer having a xylene solubles content of less than about 10 wt% and having a melt flow rate of from about 20g/10min to about 50g/10 min;

a second polymer phase combined with the first polymer phase, the second polymer phase comprising a propylene and a-olefin copolymer; and is

Wherein the polypropylene composition has a melt flow rate of 3g/10min or greater, and wherein the ratio of the melt flow rate of the first polymer phase to the melt flow rate of the polypropylene composition is greater than or equal to 1, the polypropylene composition having a xylene soluble fraction and a xylene insoluble fraction, the polypropylene composition having a total xylene soluble content of from about 12 wt% to about 25 wt%, the xylene soluble fraction containing the alpha-olefin in an amount of from about 55 wt% to about 70 wt%, the xylene insoluble fraction containing the alpha-olefin in an amount of from about 15 wt% to about 40 wt%, the polypropylene composition having a Gardner impact strength at-20 ℃ of greater than about 200 in-lbs.

2. The polypropylene composition of claim 1, wherein the composition further comprises a clarifying agent, and wherein the polypropylene composition has a haze of less than about 45% at 1 mm.

3. The polypropylene composition of claim 1 or 2, wherein the second polymer phase is in the form of polymer particles dispersed within the first polymer phase, the polymer particles having an average particle size of greater than or equal to about 1 micron.

4. The polypropylene composition according to claim 1 or 2, wherein the polypropylene polymer contained in the first polymer phase comprises a polypropylene random copolymer comprising ethylene, and wherein the second polymer phase comprises a propylene ethylene copolymer.

5. The polypropylene composition according to claim 4, wherein the ethylene content in the xylene soluble fraction of the polypropylene composition is from about 60 wt% to about 70 wt%.

6. The polypropylene composition according to claim 4, wherein the ethylene content in the xylene insoluble fraction of the polypropylene composition is from about 20 wt% to about 38 wt%.

7. The polypropylene composition according to any one of the preceding claims, wherein the composition has a flexural modulus of from about 500MPa to about 1000MPa, such as from about 650MPa to about 800 MPa.

8. The polypropylene composition of any one of the preceding claims, wherein the composition has a gardner impact strength of from about 300 inch-lbs to about 500 inch-lbs at-20 ℃.

9. The polypropylene composition of claim 4, wherein the polypropylene random copolymer in the first polymer phase contains ethylene in an amount of about 1 wt% to about 4 wt%.

10. The polypropylene composition according to claim 4, wherein the propylene ethylene copolymer in the second polymer phase contains ethylene in an amount of more than about 75 wt%, such as in an amount of more than about 80 wt%.

11. The polypropylene composition according to any one of the preceding claims, wherein the second polymer phase is present in the polypropylene composition in an amount of from about 15 wt% to about 50 wt%, such as from about 15 wt% to about 35 wt%.

12. The polypropylene composition according to any one of the preceding claims, wherein the polypropylene composition has a total xylene solubles content of from about 15 wt% to about 21 wt%.

13. The polypropylene composition according to any one of the preceding claims, wherein the polypropylene composition has a haze at 1mm of from about 15% to about 45%.

14. The polypropylene composition according to any one of the preceding claims, wherein the polypropylene composition has a clarity of more than about 90%, such as more than about 92%.

15. The polypropylene composition according to any one of the preceding claims, wherein the polypropylene composition has a melt flow rate of from about 15g/10min to about 30g/10 min.

16. The polypropylene composition according to any one of the preceding claims, wherein the polypropylene polymer in the first polymer phase has been Ziegler-Natta catalyzed, and wherein the propylene ethylene copolymer in the second polymer phase has also been Ziegler-Natta catalyzed.

17. The polypropylene composition according to claim 16, wherein the ziegler-natta catalyst used to produce the polypropylene polymer of the first polymer phase and the propylene ethylene copolymer of the second polymer phase comprises an internal electron donor comprising a substituted phenylene aromatic diester.

18. The polypropylene composition of claim 16, wherein the second polymer phase is formed in the presence of the first polymer phase.

19. The polypropylene composition according to any one of the preceding claims, wherein the polypropylene composition exhibits at least three tan delta peaks at three different temperatures.

20. The polypropylene composition according to any one of the preceding claims, wherein the composition further comprises an antacid and an antioxidant.

21. A molded article formed from the polypropylene composition of any of the preceding claims.

22. The molded article of claim 21, wherein the molded article is an injection molded article.

23. A storage container formed from the polypropylene composition according to any one of claims 1 to 20.

24. The storage container of claim 23, wherein the storage container is a food container.

Background

Transparency and impact resistance are very desirable characteristics for many polymer applications. For example, polymers can be used to produce a variety of different products, such as packages or containers where transparency can be very beneficial to the user. For example, in many cases it is highly advantageous to view the contents of the package or container through the walls of the package or container. On the other hand, high impact resistance makes the container durable.

One type of polymer that can be made highly transparent is a semi-crystalline polypropylene homopolymer. Polypropylene homopolymers are generally very translucent due to high crystallinity and large spherulites. The transparency of polypropylene polymers can be improved by incorporating ethylene or another alpha-olefin into the polymer chain to produce a polypropylene random copolymer. Nucleating and/or clarifying agents may also be incorporated into the polymer to further reduce crystal size and increase clarity.

While polypropylene random copolymers have excellent transparency characteristics, the polymers tend to have relatively low impact resistance, especially in sub-zero environments. Therefore, greater impact resistance is required for refrigerator or freezer storage containers and/or for long-term storage containers. However, when attempting to increase the impact resistance of polypropylene polymers, other characteristics of the polymers may be reduced.

In the past, polypropylene impact copolymers have been designed to include a homopolymer matrix blended with a rubbery propylene- α -olefin copolymer. The copolymer phase is intended to increase impact resistance, such as impact resistance at low temperatures. The propylene- α -olefin copolymer may be largely amorphous and, therefore, have elastomeric properties that form a rubbery phase within the polymer composition. Incorporation of propylene- α -olefin copolymers does improve impact resistance but sacrifices clarity.

In order to improve the transparency of heterophasic polypropylene compositions containing a rubber phase, the skilled person has tried to reduce the rubber phase size. For example, adding ethylene to the matrix polymer and minimizing the ethylene content in the rubber phase can be used to improve the compatibility between the matrix phase and the rubber phase. However, past attempts have failed to adequately provide polymer compositions having the desired combination of transparency and impact strength. More specifically, past attempts have failed to produce polypropylene polymer compositions having sufficient impact resistance at sub-zero temperatures.

Disclosure of Invention

In general, the present disclosure relates to a polypropylene polymer composition having an improved balance of properties. For example, polypropylene polymer compositions prepared according to the present disclosure can be formulated to have excellent clarity characteristics and excellent sub-zero impact properties. In one embodiment, the polypropylene polymer composition comprises a polypropylene polymer in combination with a propylene and alpha-olefin copolymer containing a relatively high amount of alpha-olefin. The alpha-olefin (such as ethylene) content of each polymer phase can be controlled within desired limits. In addition, the relative amounts of each polymer phase may be selected to maximize certain properties. In one embodiment, the polymers blended together are all prepared using a Ziegler-Natta catalyst system that enables careful control of different parameters and variables during polymer processing.

In one embodiment, for example, the present disclosure relates to a polypropylene composition comprising a first polymer phase combined or blended with a second polymer. The first polymer phase comprises a polypropylene polymer, such as a polypropylene random copolymer. The polypropylene random copolymer may contain an alpha-olefin (such as ethylene or butene) in an amount up to about 4 wt%, such as in an amount of about 1 wt% to about 4 wt%. The polypropylene random copolymer may have a xylene solubles fraction of less than about 10%, such as less than about 8% by weight. The polypropylene random copolymer is typically present in the polymer composition in an amount of greater than about 50 wt%, such as in an amount of greater than about 60 wt%, such as in an amount of greater than about 65 wt%. The first polymer phase may have a melt flow rate generally from about 20g/10min to about 50g/10 min.

The second polymeric phase blended with the first polymer typically comprises propylene and alpha-olefin copolymers, such as propylene ethylene copolymers, containing relatively high amounts of alpha-olefins, such as ethylene. It was found that increasing the amount of ethylene in the elastomeric or rubbery copolymer can significantly and unexpectedly improve the impact properties of the polymer composition at sub-zero temperatures, such as at temperatures below 0 ℃, such as at temperatures of-20 ℃. The amount of ethylene contained in the copolymer can be characterized by the amount of ethylene in the xylene soluble fraction and the amount of ethylene in the xylene insoluble fraction of the polypropylene composition. For example, the polypropylene composition (both the first polymer phase and the second polymer phase) may have a total xylene solubles content of from about 12 wt% to about 25 wt%. The xylene soluble fraction can contain ethylene in an amount from about 55 wt% to about 70 wt%, such as from about 60 wt% to about 70 wt%. Ethylene may be contained in the xylene insolubles portion in an amount from about 15 wt% to about 40 wt%, such as in an amount from about 20 wt% to about 38 wt%. In this regard, the propylene ethylene copolymer in the second polymer phase typically contains ethylene in an amount greater than about 75 wt%, such as in an amount greater than about 80 wt%, and typically in an amount less than about 95 wt%, such as in an amount less than about 92 wt%. In one embodiment, the ethylene is included in the second polymer phase in an amount from about 75 wt.% to about 85 wt.% (such as from about 77 wt.% to about 83 wt.%).

The heterophasic polypropylene compositions described above have excellent various physical properties. For example, the polypropylene composition may have a gardner impact strength of greater than about 200 inch-pounds (such as greater than about 250 inch-pounds, such as greater than about 300 inch-pounds, such as greater than about 350 inch-pounds) and typically less than about 500 inch-pounds when tested at-20 ℃. Additionally, the polypropylene composition may have a flexural modulus of less than about 1000MPa (such as less than about 800MPa) and typically greater than about 500MPa (such as greater than about 650 MPa). Additionally, the polypropylene composition may have a haze of less than about 45% at 1 mm. For example, the haze can be about 5% to about 45%. In addition, the polypropylene composition may have a relatively high clarity. For example, the clarity of the composition may be greater than about 90%, such as greater than about 92%.

The polypropylene composition may typically have a melt flow rate of greater than about 3g/10min (such as greater than about 5g/10min, such as greater than about 10g/10min) and typically less than about 50g/10 min. In one embodiment, the melt flow rate may be from about 15g/10min to about 25g/10 min. The ratio of the melt flow rate of the first polymer phase to the melt flow rate of the polypropylene composition is generally greater than or equal to 1. The second polymer phase is typically included in the polypropylene composition in an amount of about 15 wt% to about 50 wt%. In one embodiment, the composition may further comprise a clarifying agent for improving the transparency characteristics.

The polymer compositions of the present disclosure can be used to prepare a variety of different types of products. In one embodiment, the polymer composition can be used to form a variety of different molded articles, such as injection molded articles. In one embodiment, the polymer composition may be used to form a container, such as a storage container. The storage containers may be configured to hold food, for example, or may be used to form long-term storage containers for warehouses, attics, garages, and the like. The polymer compositions of the present disclosure are particularly useful for producing storage containers and other packaging for freezer applications or for applications where the containers will be exposed to sub-zero temperatures.

Other features and aspects of the present disclosure are discussed in more detail below.

Drawings

A full and enabling disclosure of the present disclosure, including the reference to the accompanying figures, is set forth more particularly in the remainder of the specification, in which:

fig. 1 is a perspective view of one embodiment of a container made according to the present disclosure.

Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.

Defining and testing programs

As used herein, the term "propylene-ethylene copolymer" is a copolymer containing a majority weight percent of propylene monomer with ethylene monomer as a minor component. A "propylene-ethylene copolymer" (also sometimes referred to as polypropylene random copolymer, PPR, PP-R, RCP, or RACO) is a polymer having a single repeat unit of ethylene monomer, which is present in the polymer chain in random or statistical distribution.

The Melt Flow Rate (MFR) as used herein of the propylene-based polymer is measured with a 2.16kg weight at 230 ℃ according to ASTM D1238 test method.

Xylene Solubles (XS) is defined as the weight percentage of resin that remains in solution after a polypropylene random copolymer resin sample is dissolved in hot xylene and the solution is cooled to 25 ℃. This is also referred to as the XS method using gravimetric 90 minute settling time according to ASTM D5492-06 and is also referred to herein as the "wet process". XS can also be measured according to the Viscotek method as follows: 0.4g of polymer was dissolved in 20ml of xylene and stirred at 130 ℃ for 60 minutes. The solution was then cooled to 25 ℃ and after 60 minutes the insoluble polymer fraction was filtered off. The resulting filtrate was analyzed by flow injection Polymer analysis using a Viscotek ViscoGEL H-100-3078 column with THF as the mobile phase at a flow rate of 1.0 ml/min. The columns were coupled to a Viscotek model 302 triple detector array operating at 45 ℃ with light scattering, viscometer, and refractometer detectors. Using Viscotek PolyCAL^TMPolystyrene standards maintain instrument calibration. Polypropylene (PP) homopolymer, such as biaxially oriented polypropylene (BOPP) grade Dow 5D98, was used as a reference material to ensure that the Viscotek instrument and sample preparation procedure provided consistent results by using 5D98 as a control inspection method performance. The value of 5D98 was originally derived from testing using the ASTM method specified above.

The above ASTM D5492-06 method may be suitable for determining the xylene soluble fraction. Generally, the procedure consists of the following steps: 2g of sample was weighed and dissolved in a 400ml flask with 24/40 adapterDissolved in 200ml o-xylene. The flask was connected to a water cooled condenser and placed under nitrogen (N)₂) The contents were stirred and heated to reflux under conditions, and then maintained at reflux for an additional 30 minutes. The solution was then cooled in a temperature-controlled water bath at 25 ℃ for 90 minutes to crystallize the xylene insoluble fraction. Once the solution was cooled and the insoluble fraction precipitated from the solution, separation of the xylene soluble fraction (XS) from the xylene insoluble fraction (XI) was achieved by filtration through 25 micron filter paper. 100ml of the filtrate was collected in a pre-weighed aluminum pan and o-xylene was evaporated from this 100ml of filtrate under a stream of nitrogen. After evaporation of the solvent, the pan and contents were placed in a vacuum oven at 100 ℃ for 30 minutes or until dry. The pan was then cooled to room temperature and weighed. The xylene soluble fraction was calculated as XS (wt%) [ (m)₃-m₂)*2/m₁]100, wherein m₁Is the initial weight of the sample used, m₂Is the weight of an empty aluminum pan, and m₃Is the weight of the disc and residue (asterisk multiplication of the indicated terms or values is indicated here and elsewhere in this disclosure).

By passing¹³C-NMR measured the ethylene content of the Xylene Solubles (XS) fraction and Xylene Insolubles (XI). The sample was prepared by adding approximately 2.7g of a 50/50 mixture of tetrachloroethane-d 2/o-dichlorobenzene containing 0.025M Cr (AcAc)3 to 0.20g of the sample in a Norell 1001-710mm NMR tube. The sample was dissolved and homogenized by heating the tube and its contents to 150 ℃ using a heating block. Each sample was visually inspected to ensure uniformity. Data were collected using a Bruker 400MHz spectrometer equipped with a Bruker Dual DUL high temperature CryoProbe (CryoProbe). Data was collected using 500 transients per data file, 6 second pulse repetition delay, 90 degree flip angle, and back-gated decoupling with a sample temperature of 120 ℃. All measurements were performed on a non-rotating sample in locked mode. The samples were heat equilibrated for 10 minutes prior to data acquisition.

Ethylene content was calculated based on the triad distribution. The chemical shift assignments for the triads are shown in table 1.

PPP＝(F+A-0.5D)/2

PPE＝D

EPE＝C

EEE＝(E-0.5G)/2

PEE＝G

PEP＝H

The ethylene content was calculated based on:

molar number P-sum of triads centred on P

Molar number E ═ sum of triads centred on E

TABLE 1 chemical Shift assignment of ethylene propylene copolymers to triads

	Chemical | Displacement δ (ppm)	Three-part body	Carbon type	Chemical shift range	Region(s)
						1	44-49	PPE	CH2	44.0-49.0	A
2		PPP	CH2
						3	37.8	EPE(P)	CH2	36.0-39.0	B
4	37.4	EPE(E)	CH2
						5	33.2	EPE	CH	32.8-34.0	C
6	31.0	PPE	CH	31.00	D
						7	30.8	PEE(P)	CH2	29.7-30.8	E
8	30.4	PEE(E)	CH2
						9	30.0	EEE	CH2
10	28.8	PPP	CH	28.0-29.7	F
						11	27.3	EEP	CH2	26.0-28.3	G
12	24.6	PEP	CH2	24.0-26.0	H
						13	21.6	PPP	CH3	19.0-23.0	I
14	20.8	PPE	CH3
						15	20.0	EPE	CH3

The Koenig B value (which is a measure of the degree of randomness or blockiness in the copolymer) is calculated by: koenig B ═ EP ]/(2[ P ] [ E ]), where [ EP ] is the total molar fraction of EP dimers (EP + PE). ("Spectroscopy of Polymers" 2 nd edition, Jack L. Koenig, 1999, Elsevier; pages 17-18).

Flexural modulus was determined according to ASTM D790-10 method A using type 1 specimens at 1.3mm/min according to ASTM 3641 and molded according to ASTM D4101.

Mw/Mn (also referred to as "MWD") and Mz/Mw are measured by Gel Permeation Chromatography (GPC) for polypropylene according to GPC analysis methods. The polymers were analyzed on a PL-220 series high temperature Gel Permeation Chromatography (GPC) apparatus equipped with a refractometer detector and four PL gel Mixed A (PLgel Mixed-A) (20 μm) columns (Polymer Laboratory Inc.). The oven temperature was set to 150 ℃ and the temperatures of the hot and warm zones of the autosampler were set to 135 ℃ and 130 ℃ respectively. The solvent was 1,2, 4-Trichlorobenzene (TCB) containing about 200ppm of 2, 6-di-tert-butyl-4-methylphenol (BHT) purged with nitrogen. The flow rate was 1.0mL/min and the injection volume was 200. mu.l. Samples were prepared at a concentration of 2mg/mL by: the sample was dissolved in TCB (containing 200ppm BHT) purged with N2 and preheated for 2.5 hours at 160 deg.C with gentle stirring.

The GPC column set was calibrated by running 20 narrow molecular weight distribution polystyrene standards. The Molecular Weight (MW) of the standard ranged from 580 to 8,400,000g/mol, and the standard was contained in 6 "cocktail" mixtures. The individual molecular weights in each standard mixture are at least ten times apart. For the case where the molecular weight is equal to or greater than 1,000,000g/mol, 0.005g is dissolved in 20mL of the solvent to prepare a polystyrene standard, and for the case where the molecular weight is less than 1,000,000g/mol, 0.001g is dissolved in 20mL of the solvent to prepare a polystyrene standard. The polystyrene standards were dissolved at 150 ℃ for 30 minutes with stirring. The narrow standard mixture was run first and in order of decreasing highest molecular weight component to minimize degradation effects. A fourth order polynomial fit was used to generate the log molecular weight correction as a function of elution volume. The polypropylene equivalent molecular weight was calculated by using the following formula and reported Mark-Ha temperature coefficients for polypropylene (Th.G.Scholte, N.L.J.Meijerink, H.M.Schofflers and A.M.G.Brands, J.appl.Polym.Sci., 29, 3763-:

wherein M is_ppIs PP equivalent MW, M_PSThe log K and α values for the Mark-Hough temperature coefficients for PP and PS for the PS equivalent MW are listed in Table 2 below.

Izod (IZOD) impact strength was measured according to ASTM D256.

Gardner impact testing was measured according to ASTM D5420.

Haze and clarity were measured according to ASTM test D1003 procedure A and D1746 using BYK Gardner Haze-Gard Plus 4725 and injection molded plaques having a thickness of 1 mm.

Tan δ was measured by DMA testing using a TA instrument Q800 with a double cantilever clamp. Specimens with dimensions of 12.7mm by 3.2mm by 60mm were cut from the flexural modulus specimens. The sample was first equilibrated at-150 ℃ and isothermally held for 5 minutes, and then heated to 100 ℃ at a heating rate of 3 ℃/min.

The term β/α relates to the ratio of the molecular weight of the copolymer of the discontinuous phase to the molecular weight of the propylene-based polymer of the continuous phase, where β and α are the values of intrinsic viscosity of the copolymer and the propylene-based polymer fraction, respectively, as measured in decalin at 135 ℃ (ASTM D1601). For the purposes of this disclosure, the value of β/α is calculated from the MFR of the matrix polymer, the MFR of the bulk impact copolymer, and the Fc prior to visbreaking as follows:

the rubber particle size was measured by Scanning Electron Microscopy (SEM) machine Hitachi Tabletop Microscope (TM) 3030 Plus. The samples were first cut from the center of the Izod impact test plate (ASTM D4101) in the flow direction, then the sections were frozen at-20 ℃ and RuO₄Staining and further freezing the sections at-20 ℃. SEM images were observed in a Backscattering (BSE) mode, in which the highly stained regions (EPR rubber) are the brighter phase, andand the lightly stained areas are the darker phases. ByThe Premier software captures and analyzes particle size. D50 was calculated with the meaning of particle size at 50% cumulative volume fraction.

Detailed Description

One of ordinary skill in the art will understand that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present disclosure.

Generally, the present disclosure relates to polypropylene compositions having a unique combination of physical properties. For example, in one embodiment, the polymer composition can be formulated to have not only excellent transparency characteristics, but also excellent impact resistance characteristics. In addition, the polymer composition can be formulated to have good flow characteristics. Thus, the polymer composition is particularly suitable for forming injection molded articles. In one embodiment, for example, the polymer composition may be used to form a container, particularly a storage container in which a product or item placed in the container may be viewed through the container or a wall of the package. The polypropylene compositions of the present disclosure are particularly useful for producing freezer packaging and containers.

Generally, the polypropylene compositions of the present disclosure comprise a heterophasic composition. In particular, the polypropylene composition comprises a first polymer phase blended with a second polymer phase. Both polymer phases are formed from polypropylene copolymers containing controlled amounts of alpha-olefins, such as ethylene or butylene. For example, in one embodiment, the first polymer phase comprises a polypropylene random copolymer containing ethylene in an amount up to about 4 wt%. The first polymer phase is typically present in the polymer composition in an amount greater than the second polymer phase, thereby forming the matrix polymer. In another aspect, the second polymer phase comprises a polypropylene copolymer having elastomeric or rubbery characteristics. According to the present disclosure, the second polymer phase comprises a greater amount of ethylene than propylene. It was found that a large increase in the ethylene level in the second polymer phase can significantly improve the impact properties of the polymer composition at sub-zero temperatures. Unexpectedly having improved toughness properties at low temperatures and having excellent clarity properties makes the polypropylene composition very suitable for producing containers to be used in low temperature environments.

For example, the polymer composition may exhibit a gardner impact resistance of greater than about 200 inch-pounds (such as greater than about 225 inch-pounds, such as greater than about 250 inch-pounds, such as greater than about 275 inch-pounds, such as greater than about 300 inch-pounds, such as greater than about 325 inch-pounds) and typically less than about 500 inch-pounds at-20 ℃ when tested according to the gardner impact test.

As described above, in addition to excellent impact strength properties, the polymer compositions of the present disclosure may also have very good transparency properties. For example, the polymer composition may have a haze at 1mm of less than about 45% (such as less than about 40%, such as less than about 35%, such as even less than about 30%). Haze at 1mm is typically greater than about 10%.

In addition to relatively low haze, the polypropylene compositions of the present disclosure may also exhibit excellent clarity characteristics. For example, the polymer composition can exhibit a clarity of greater than about 80% (such as greater than about 85%, such as greater than about 90%, such as greater than about 92%).

The flexible nature of the polymer composition can vary depending on a number of factors, including the relative amounts of the first and second polymer phases and the amount of comonomer in the first and second phases. Generally, the generally disclosed polymeric compositions can have a flexural modulus of less than about 1000MPa (such as less than about 850MPa, such as less than about 800MPa, such as less than about 750 MPa). Generally, the flexural modulus is greater than about 500MPa, such as greater than about 550MPa, such as greater than about 600 MPa.

The term β/α relates to the ratio of the molecular weight of the copolymer to the molecular weight of the matrix polymer or the polymer of the first polymer phase. The molecular weight of each polymer is proportional to the intrinsic viscosity of each polymer. Intrinsic viscosity indicates the viscosity of a solution of a polymer in a given solvent at a given temperature. The polymer compositions of the present disclosure can have a beta/alpha ratio greater than about 1 (such as greater than or equal to 1.1). For example, the β/α ratio may be greater than about 1.2, such as greater than about 1.3. Typically, the beta/alpha ratio is less than about 2, such as less than about 1.8, such as less than about 1.6.

Polymer compositions formulated according to the present disclosure may also have excellent flow characteristics while maintaining relatively high impact strength. For example, the polymer compositions of the present disclosure can have a melt flow rate of greater than about 3g/10min (such as greater than about 15g/10min, such as greater than about 17g/10min, such as greater than about 18g/10 min). The melt flow rate is typically less than about 80g/10min, such as less than about 70g/10min, such as less than about 50g/10min, such as less than about 35g/10min, such as less than about 30g/10 min. The above-mentioned flow characteristics make the polymer composition very suitable for use in injection molding applications.

As noted above, the polypropylene compositions of the present disclosure generally comprise a first phase polymer in combination with a second phase polymer. The first phase polymer comprises a polypropylene polymer, such as a random copolymer of polypropylene. The random copolymer may be, for example, a copolymer of propylene and an alpha-olefin, such as ethylene or butene. The polypropylene random copolymer forms the matrix polymer in the polypropylene composition and may contain alpha-olefins in an amount up to about 4 wt%, such as in an amount less than about 3.8 wt%, such as in an amount less than about 3.5 wt%, and typically in an amount greater than about 0.5 wt%, such as in an amount greater than about 1 wt%, such as in an amount greater than about 1.5 wt%, such as in an amount greater than about 2 wt%. The first phase polymer may have a xylene solubles content typically less than about 12 wt% (such as in an amount less than about 10 wt%, such as in an amount less than about 8 wt%, such as in an amount less than about 7 wt%). The xylene solubles content is typically greater than about 0.5 wt.%, such as greater than about 3 wt.%.

As will be described in more detail below, the first phase polymer may comprise a ziegler-natta catalyzed polymer and may have a relatively broad molecular weight distribution. For example, the molecular weight distribution (Mw/Mn) is greater than about 3.8 (such as greater than about 4, such as greater than about 4.3, such as greater than about 4.5, such as greater than about 4.8, such as greater than about 5, such as greater than about 5.2, such as greater than about 5.5, such as greater than about 5.7, such as greater than about 6) and typically less than about 9 (such as less than about 8.5, such as less than about 8). The weight average molecular weight of the first phase polymer (as determined by GPC) is typically greater than about 100,000, such as greater than about 120,000.

In one embodiment, the polypropylene random copolymer comprising the first phase polymer has a relatively high melt flow rate. For example, the first phase polymer may have a melt flow rate of greater than about 15g/10min (such as greater than about 18g/10min, such as greater than about 20g/10min, such as greater than about 22g/10min, such as greater than about 25g/10 min). The melt flow rate of the first phase polymer is typically less than about 80g/10min, such as less than about 50g/10 min.

The second phase polymer is a copolymer of propylene and an alpha-olefin. In addition, the second phase polymer has elastomeric or rubbery properties. Thus, the second phase polymer can significantly improve the impact strength resistance of the polymer composition.

In accordance with the present disclosure, the second phase polymer contains a relatively higher amount of alpha-olefin relative to the amount of propylene contained in the second polymer phase. For example, in one embodiment, the second phase polymer contains ethylene in an amount greater than the amount of propylene present. It has been found that increasing the ethylene content in the second polymer phase unexpectedly and significantly improves the impact properties of the polymer composition at sub-zero temperatures.

The amount of ethylene contained in the second polymer phase can be characterized or quantified by examining the amount of ethylene in the xylene solubles and xylene insolubles. For example, the polypropylene compositions of the present disclosure may have a total xylene solubles content typically of more than about 12 wt% (such as more than about 15 wt%, such as more than about 18 wt%, such as more than about 20 wt%) and typically of less than about 40 wt% (such as less than about 30 wt%, such as less than about 25 wt%, such as less than about 21 wt%). Thus, the polypropylene composition comprises a xylene soluble fraction and a xylene insoluble fraction. In accordance with the present disclosure, ethylene may be included in the xylene solubles portion in an amount greater than about 55 wt% (such as in an amount greater than about 58 wt%, such as in an amount greater than about 60 wt%) and typically in an amount less than about 70 wt% (such as in an amount less than about 68 wt%). On the other hand, the amount of ethylene contained in the xylene insolubles portion can generally be greater than about 15 wt% (such as greater than about 18 wt%, such as greater than about 20 wt%) and generally less than about 50 wt% (such as less than about 40 wt%, such as less than about 38 wt%).

Based on the above ranges, ethylene is believed to be contained in the second polymer phase in an amount greater than about 75 wt%, such as in an amount greater than about 80 wt%, such as in an amount greater than about 85 wt%, and typically in an amount less than about 95 wt%, such as in an amount less than about 90 wt%.

The second phase polymer may have a weight average molecular weight of at least about 130,000 (such as at least about 140,000, such as at least about 150,000) and typically less than about 500,000.

The first phase polymer generally forms a matrix and the second phase polymer forms particles within the matrix. In the past, various attempts have been made to reduce the size of the second phase polymer particles. However, in the polymer compositions of the present disclosure, the second phase polymer particles have a relatively large size. It has been unexpectedly found that excellent physical properties, including clarity and haze, can be obtained while still having relatively large second phase polymer particles. For example, the second phase polymer particles may have an average particle size (D50) of greater than about 1 micron (such as greater than about 1.1 microns) and typically less than about 8 microns (such as less than about 6 microns, such as less than about 4 microns). The average particle size may be, for example, greater than about 1.5 microns, such as greater than about 2 microns, such as greater than about 2.5 microns, such as even greater than 3 microns. For example, in one embodiment, the average particle size may be from about 1 micron to about 5 microns. In one embodiment, greater than 50% of the particles contained in the second phase polymer may be greater than about 2 microns, such as greater than about 3 microns, based on volume fraction. For example, in one embodiment, 50% of the particles have a particle size in volume fraction of about 3 microns to about 5 microns.

The relative amounts of the different phases contained in the polymer composition can vary depending on a variety of factors and desired results. Generally, the second polymer phase may be included in the polypropylene composition in an amount of greater than about 15 wt%, such as in an amount of greater than about 20 wt%, such as in an amount of greater than about 25 wt%, such as in an amount of greater than about 30 wt%, such as in an amount of greater than about 35 wt%, and typically in an amount of less than about 60 wt%, such as in an amount of less than about 50 wt%, such as in an amount of less than about 40 wt%, such as in an amount of less than about 35 wt%. For example, the second phase polymer may be present in the composition in an amount greater than about 15% by weight and in an amount less than about 60% by weight (including all increments therebetween of 1% by weight).

The polypropylene compositions of the present disclosure may contain various other additives and ingredients in addition to the first phase polymer and the second phase polymer. For example, the polypropylene composition may contain nucleating agents, mold release agents, slip agents, antiblocking agents, UV stabilizers, heat stabilizers (e.g., DSTDP), colorants/colorants, and the like. In one embodiment, the polymer composition may contain an antioxidant, such as a hindered phenol antioxidant. The polymer composition may also contain an acid scavenger. Each of the additives is typically present in the polymer composition in an amount of less than about 3 wt.%, such as less than about 2 wt.%, such as less than about 1 wt.%, such as less than about 0.5 wt.%, and typically greater than about 0.001 wt.%.

In one embodiment, the polypropylene composition may further contain a clarifying agent. Clarifying agents may be added to further improve the transparency characteristics of the composition. The clarifying agent may, for example, comprise a compound capable of creating a gelled network within the composition.

In one embodiment, the clarifying agent may include a sorbitol compound, such as a sorbitol acetal derivative. In one embodiment, for example, the clarifying agent can include dibenzyl sorbitol.

With respect to sorbitol acetal derivatives, which may be used as additives in some embodiments, the sorbitol acetal derivatives are shown in formula (I):

wherein R1-R5 comprise the same or different moieties selected from hydrogen and C1-C3 alkyl.

In some embodiments, R1-R5 are hydrogen, such that the sorbitol acetal derivative is 2, 4-dibenzylidene sorbitol ("DBS"). In some embodiments, R1, R4, and R5 are hydrogen, and R2 and R3 are methyl groups, such that the sorbitol acetal derivative is 1, 3: 2, 4-di-p-methyldibenzylidene-D-sorbitol ("MDBS"). In some embodiments, R1-R4 are methyl groups and R5 is hydrogen such that the sorbitol acetal derivative is a 1, 3: 2, 4-bis (3, 4-dimethylol benzylidene) sorbitol ("DMDBS"). In some embodiments, R2, R3, and R5 are propyl groups (-CH2-CH2-CH3), and R1 and R4 are hydrogen, such that the sorbitol acetal derivative is a 1,2, 3-trideoxy-4, 6: 5, 7-bis-O- (4-propylphenylmethylene) nonanol ("TBPMN").

Other embodiments of clarifying agents that may be used include:

1,3: 2, 4-dibenzylidene sorbitol

1,3: 2, 4-bis (p-methylbenzylidene) sorbitol

Bis (p-methylbenzylidene) sorbitol

Bis (p-ethylbenzylidene) sorbitol

Bis (5 ', 6', 7 ', 8' -tetrahydro-2-naphthylidene) sorbitol

In one embodiment, the fining agent may further comprise a bisamide, such as a benzenetriamide. The above clarifying agents may be used alone or in combination.

When present in the polymer composition, the one or more clarifying agents are typically added in an amount greater than about 200ppm (such as an amount greater than about 1,800ppm, such as an amount greater than about 2,000ppm, such as an amount greater than about 2,200 ppm). The one or more fining agents are typically present in an amount less than about 5,000ppm (such as less than about 4,000ppm, such as less than about 3,000ppm, such as less than about 2,000 ppm). The amount of clarifying agent present in the composition can depend on a variety of factors, including the type of clarifying agent used.

Various different polymerization methods and procedures can be used to produce the first phase polymer and the second phase polymer. In one embodiment, a ziegler-natta catalyst is used to produce the polymer composition. For example, olefin polymerization can occur in the presence of a catalyst system comprising a catalyst, an internal electron donor, a cocatalyst, and optionally an external electron donor.Formula CH₂Olefins of ═ CHR, where R is hydrogen or a hydrocarbon group having 1 to 12 atoms, can be contacted with the catalyst system under suitable conditions to form a polymer product. Copolymerization may occur during the process steps in order to produce the heterophasic composition of the present disclosure. The polymerization process may be carried out using known techniques, in the gas phase using a fluidized or stirred bed reactor, or in the slurry phase using an inert hydrocarbon solvent or diluent or liquid monomer.

In one embodiment, the first phase polymer and the second phase polymer may be produced in a two-stage process comprising a first stage in which the propylene random copolymer of the continuous polymer phase is produced and a second stage in which the propylene copolymer is produced. The first stage polymerization may be carried out in one or more bulk reactors or in one or more gas phase reactors. The second stage polymerization may be carried out in one or more gas phase reactors. The second stage polymerization is usually carried out directly after the first stage polymerization. For example, the polymerization product recovered from the first polymerization stage may be passed directly to the second polymerization stage. In this regard, the polymerization may be carried out according to a sequential polymerization process. Producing a heterophasic copolymer composition.

In one embodiment of the present disclosure, the polymerization is carried out in the presence of a stereoregular olefin polymerization catalyst. For example, the catalyst may be a ziegler-natta catalyst. For example, in one embodiment, a catalyst sold under the trade name CONSISTA and commercially available from W.R. Grace & Company may be used. In one embodiment, the electron donor is selected to be phthalate free.

In one embodiment, the catalyst comprises a procatalyst composition containing a titanium moiety, such as titanium chloride, a magnesium moiety, such as magnesium chloride, and at least one internal electron donor.

The procatalyst precursor may include (i) magnesium, (ii) a transition metal compound from groups IV through VII of the periodic table, (iii) a halide, oxyhalide, and/or alkoxide of (i) or (i) and/or (ii), and (IV) a combination of (i), (ii), and (iii). Non-limiting examples of suitable procatalyst precursors include halides, oxyhalides, alkoxides, and combinations thereof of magnesium, manganese, titanium, vanadium, chromium, molybdenum, zirconium, hafnium.

In one embodiment, the procatalyst precursor contains magnesium as the sole metal component. Non-limiting examples include anhydrous magnesium chloride and/or its alcohol adducts, magnesium alkoxides and/or aryl ether magnesium, mixed alkoxy magnesium halides and/or carboxylated magnesium diols or aryl ether magnesium.

In one embodiment, the procatalyst precursor is an alcohol adduct of anhydrous magnesium chloride. Anhydrous magnesium chloride adducts are generally defined as MgCl₂-nROH, wherein n has a range of 1.5-6.0, preferably 2.5-4.0, and most preferably 2.8-3.5 moles of total alcohols. ROH is straight-chain or branched C₁-C₄An alcohol, or a mixture of alcohols. Preferably, ROH is ethanol, or a mixture of ethanol and a higher alcohol. If the ROH is a mixture, the molar ratio of ethanol to higher alcohol is at least 80: 20, preferably 90: 10, and most preferably at least 95: 5.

In one embodiment, the substantially spherical MgCl can be formed by a spray crystallization process₂-nEtOH adduct. In one embodiment, the MgCl is in spherical form₂Average particle size of precursor (Malvern d)₅₀) Between about 15-150 microns, preferably between 20-100 microns, and most preferably between 35-85 microns.

In one embodiment, the procatalyst precursor contains a transition metal compound and a magnesium metal compound. The transition metal compound has the general formula TrXx, wherein Tr is a transition metal, and X is halogen or C_1-10Hydrocarbyloxy or hydrocarbyl groups, and X is the number of such X groups in the compound, as well as in the magnesium metal compound. Tr may be a group IV, group V or group VI metal. In one embodiment, Tr is a group IV metal, such as titanium. X can be chloride ion, bromide ion, C_1-4Alkoxide or phenoxide or mixtures thereof. In one embodiment, X is chloride.

The precursor composition can be prepared by chlorination of the above-described mixed magnesium compound, titanium compound, or a mixture thereof.

In one embodiment, the precursor composition is of the formula Mg_dTi(OR^e)_fX_gIn which R is a mixed magnesium/titanium compound of^eIs an aliphatic or aromatic hydrocarbon radical having from 1 to 14 carbon atoms or COR ', wherein R' is an aliphatic or aromatic hydrocarbon radical having from 1 to 14 carbon atoms; each OR^eThe radicals are identical or different; x is independently chlorine, bromine or iodine; d is 0.5 to 56; or 2-4, or 3; f is 2 to 116, or 5 to 15; and g is 0.5 to 116, or 1 to 3.

According to the present disclosure, the above-described procatalyst precursor is combined with at least one internal electron donor. The internal electron donor may comprise a substituted phenylene aromatic diester.

In one embodiment, the first internal electron donor comprises a substituted phenylene aromatic diester having the following structure (I):

wherein R is₁-R₁₄Are the same or different. R₁-R₁₄Each of which is selected from the group consisting of hydrogen, substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, heteroatoms, and combinations thereof. R₁-R₁₄At least one of which is not hydrogen.

In one embodiment, the substituted phenylene aromatic diester can be any substituted phenylene aromatic diester as disclosed in U.S. patent application serial No. 61/141,959, filed 12/31/2008, which is incorporated herein by reference in its entirety.

In one embodiment, the substituted phenylene aromatic diester can be any substituted phenylene aromatic diester as disclosed in WO12088028, filed 12/20/2011, the entire contents of which are incorporated herein by reference.

In one embodiment, R₁-R₄At least one of(or two, or three, or four) R groups are selected from substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, heteroatoms, and combinations thereof.

In one embodiment, R₅-R₁₄At least one (or some, or all) of the R groups in (a) are selected from substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, heteroatoms, and combinations thereof. In another embodiment, R₅-R₉At least one of (1) and R₁₀-R₁₄At least one of which is selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, heteroatoms, and combinations thereof.

In one embodiment, R₁-R₄At least one of (1) and R₅-R₁₄At least one of which is selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, heteroatoms, and combinations thereof. In another embodiment, R₁-R₄At least one of (1), R₅-R₉At least one of (1) and R₁₀-R₁₄At least one of which is selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, heteroatoms, and combinations thereof.

In one embodiment, R₁-R₄Any consecutive R groups in (a), and/or R₅-R₉Any consecutive R groups in (a), and/or R₁₀-R₁₄Any consecutive R groups in (a) may be linked to form an inter-ring structure or an intra-ring structure. The structure between/within the rings may or may not be aromatic. In one embodiment, the inter-ring structure/intra-ring structure is C₅Or C₆A membered ring.

In one embodiment, R₁-R₄At least one of which is selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, and combinations thereof. Optionally, R₅-R₁₄At least one of which may be a halogen atom or an alkoxy group having 1 to 20 carbon atoms. Optionally, R₁-R₄And/or R₅-R₉And/or R₁₀-R₁₄May be joined to form an inter-ring structure or an intra-ring structure. The structures in the rings may or may not be aromatic.

In one embodiment, R₁-R₄And/or R₅-R₉And/or R₁₀-R₁₄Wherein any consecutive R groups may be C₅-C₆A member of a membered ring.

In one embodiment, structure (I) includes R₁、R₃And R₄Is hydrogen. R₂Selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, and combinations thereof. R₅-R₁₄Are the same or different, and R₅-R₁₄Each of which is selected from the group consisting of hydrogen, substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, halogens, and combinations thereof.

In one embodiment, R₂Is selected from C₁-C₈Alkyl radical, C₃-C₆Cycloalkyl or substituted C₃-C₆A cycloalkyl group. R₂There may be mentioned methyl groups, ethyl groups, n-propyl groups, isopropyl groups, tert-butyl groups, isobutyl groups, sec-butyl groups, 2,4, 4-trimethylpent-2-yl groups, cyclopentyl groups and cyclohexyl groups.

In one embodiment, structure (I) includes R₂Is methyl, and R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₂Is ethyl, and R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₂Is tert-butyl, and R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₂Is ethoxycarbonyl, and R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₂、R₃And R₄Are all hydrogen, and R₁Selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, and combinations thereof. R₅-R₁₄Are the same or different and are each selected from the group consisting of hydrogen, substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, halogens, and combinations thereof.

In one embodiment, structure (I) includes R₁Is methyl, and R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₂And R₄Is hydrogen, and R₁And R₃Are the same or different. R₁And R₃Each of which is selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, and combinations thereof. R₅-R₁₄Are the same or different, and R₅-R₁₄Each of which is selected from the group consisting of substituted hydrocarbyl groups having 1 to 20 carbon atoms, unsubstituted hydrocarbyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, halogens, and combinations thereof.

In one embodiment, structure (I) includes R₁And R₃Are the same or different. R₁And R₃Each of which is selected from C₁-C₈Alkyl radical, C₃-C₆Cycloalkyl radicals or substituted C₃-C₆A cycloalkyl group. R₅-R₁₄Are the same or different, and R₅-R₁₄Each of which is selected from hydrogen, C₁-C₈Alkyl groups and halogens. Suitable C₁-C₈Non-limiting examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, and neopentyl,

Tert-amyl, n-hexyl and 2,4, 4-trimethylpent-2-yl groups. Suitable C₃-C₆Non-limiting examples of cycloalkyl groups include cyclopentyl and cyclohexyl groups. In another embodiment, R₅-R₁₄At least one of is C₁-C₈An alkyl group or a halogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₂、R₄And R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁And R₃Is an isopropyl group. R₂、R₄And R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁、R₅And R₁₀Each of which is a methyl group, and R₃Is a tert-butyl group. R₂、R₄、R₆-R₉And R₁₁-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁、R₇And R₁₂Each of which is a methyl group, and R₃Is a tert-butyl group. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is an ethyl group. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁、R₅、R₇、R₉、R₁₀、R₁₂And R₁₄Each of which is a methyl group, and R₃Is a tert-butyl group. R₂、R₄、R₆、R₈、R₁₁And R₁₃Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₅、R₇、R₉、R₁₀、R₁₂And R₁₄Each of which is an isopropyl group. R₂、R₄、R₆、R₈、R₁₁And R₁₃Each of which is hydrogen.

In one embodiment, the substituted phenylene aromatic diester has structure (II) comprising R₁Is a methyl group, and R₃Is a tert-butyl group. R₂And R₄Each of which is hydrogen. R₈And R₉Is C forming a 1-naphthoyl moiety₆A member of a membered ring. R₁₃And R₁₄Is C forming another 1-naphthoyl moiety₆A member of a membered ring. Structure (II) is provided below.

In one embodiment, the substituted phenylene aromatic diester has structure (III) comprising R₁Is a methyl group, and R₃Is a tert-butyl group. R₂And R₄Each of which is hydrogen. R₆And R₇Is C forming a 2-naphthoyl moiety₆A member of a membered ring. R₁₂And R₁₃Is C forming a 2-naphthoyl moiety₆A member of a membered ring. Structure (III) is provided below.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is an ethoxy group. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is a fluorine atom. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is a chlorine atom. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is a bromine atom. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, the knotR comprised in structure (I)₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is an iodine atom. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₆、R₇、R₁₁And R₁₂Each of which is a chlorine atom. R₂、R₄、R₅、R₈、R₉、R₁₀、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₆、R₈、R₁₁And R₁₃Each of which is a chlorine atom. R₂、R₄、R₅、R₇、R₉、R₁₀、R₁₂And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₂、R₄And R₅-R₁₄Each of which is a fluorine atom.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is a trifluoromethyl group. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is an ethoxycarbonyl group. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is an ethoxy group. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a tert-butyl group. R₇And R₁₂Each of which is a diethylamino group. R₂、R₄、R₅、R₆、R₈、R₉、R₁₀、R₁₁、R₁₃And R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group, and R₃Is a 2,4, 4-trimethylpentan-2-yl radical. R₂、R₄And R₅-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁And R₃Each of which is a sec-butyl group. R₂、R₄And R₅-R₁₄Each of which is hydrogen.

In one embodiment, the substituted phenylene aromatic diester has structure (IV) whereby R₁And R₂Is C forming a 1, 2-naphthalene moiety₆A member of a membered ring. R₅-R₁₄Each of which is hydrogen. Structure (IV) is provided below.

In one embodiment, the substituted phenylene aromatic diester has the structure (V), whereby R₂And R₃Is to form 2, 3-naphthalenePart C₆A member of a membered ring. R₅-R₁₄Each of which is hydrogen. Structure (V) is provided below.

In one embodiment, structure (I) includes R₁And R₄Each is a methyl group. R₂、R₃、R₅-R₉And R₁₀-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁Is a methyl group. R₄Is an isopropyl group. R₂、R₃、R₅-R₉And R₁₀-R₁₄Each of which is hydrogen.

In one embodiment, structure (I) includes R₁、R₃And R₄Each of which is an isopropyl group. R₂、R₅-R₉And R₁₀-R₁₄Each of which is hydrogen.

In one embodiment, R₁And R₄Each of which is selected from a methyl group, an ethyl group, and a vinyl group. R₂And R₃Each of which is selected from hydrogen, a secondary alkyl group or a tertiary alkyl group, wherein R is₂And R₃Not hydrogen at the same time. In other words, when R2 is hydrogen, R3 is not hydrogen (and vice versa).

In one embodiment, a second internal electron donor may be used, which typically comprises a polyether that can coordinate in a bidentate fashion. In one embodiment, the second internal electron donor is a substituted 1, 3-diether having structure VI:

wherein R is₁And R₂Are identical or different and are methyl, C₂-C₁₈Straight or branched alkyl, C₃-C₁₈Cycloalkyl radical, C₄-C₁₈Cycloalkyl-alkyl, C₄-C₁₈Alkyl-cycloalkyl, phenyl, organosilicon, C₇-C₁₈Arylalkyl radical or C₇-C₁₈An alkylaryl group; and R is₁Or R₂And may also be a hydrogen atom.

In one embodiment, the second internal electron donor may comprise a 1, 3-diether having a cyclic or polycyclic structure VII:

wherein R is₁、R₂、R₃And R₄Is as for R of structure VI₁And R₂Said, or may be combined to form one or more C₅-C₇A fused aromatic or non-aromatic ring structure optionally containing N, O or S heteroatoms. Specific examples of the second internal electron donor include:

4, 4-bis (methoxymethyl) -2, 6-dimethylheptane, 9-bis (methoxymethyl) fluorene, or a mixture thereof.

The precursor is converted to a solid procatalyst by further reaction (halogenation) with an inorganic halide compound, preferably a titanium halide compound, and incorporation of an internal electron donor.

One suitable method for halogenating the precursor is by reacting the precursor at elevated temperature with a tetravalent titanium halide, optionally in the presence of a hydrocarbon or halocarbon diluent. The preferred tetravalent titanium halide is titanium tetrachloride.

The resulting procatalyst composition may generally contain titanium in an amount from about 0.5 wt.% to about 6 wt.%, such as from about 1.5 wt.% to about 5 wt.%, such as from about 2 wt.% to about 4 wt.%. The solid catalyst may contain magnesium typically in an amount of greater than about 5 wt.%, such as in an amount of greater than about 8 wt.%, such as in an amount of greater than about 10 wt.%, such as in an amount of greater than about 12 wt.%, such as in an amount of greater than about 14 wt.%, such as in an amount of greater than about 16 wt.%. Magnesium is contained in the catalyst in an amount of less than about 25 wt.%, such as less than about 23 wt.%, such as less than about 20 wt.%. The internal electron donor may be present in the catalyst composition in an amount of less than about 30 wt%, such as in an amount of less than about 25 wt%, such as in an amount of less than about 22 wt%, such as in an amount of less than about 20 wt%, such as in an amount of less than about 19 wt%. The internal electron donor is typically present in an amount greater than about 5 wt.%, such as greater than about 9 wt.%.

In one embodiment, the procatalyst composition is combined with a cocatalyst to form a catalyst system. The catalyst system is a system that forms an olefin-based polymer when contacted with an olefin under polymerization conditions. The catalyst system may optionally comprise an external electron donor, an activity limiting agent, and/or various other components.

As used herein, a "cocatalyst" is a substance capable of converting a procatalyst into an active polymerization catalyst. The promoter may comprise hydrides, alkyls, or aryls of aluminum, lithium, zinc, tin, cadmium, beryllium, magnesium, and combinations thereof. In one embodiment, the cocatalyst is of the formula R₃A hydrocarbyl aluminum cocatalyst represented by Al, wherein each R is an alkyl, cycloalkyl, aryl, or hydride group; at least one R is a hydrocarbyl group; two or three R groups may be joined in a cyclic group, thereby forming a heterocyclic structure; each R may be the same or different; and each R that is a hydrocarbyl group has from 1 to 20 carbon atoms, and preferably from 1 to 10 carbon atoms. In another embodiment, each alkyl group may be straight or branched chain, and such hydrocarbyl groups may be mixed groups, i.e., the groups may contain alkyl, aryl, and/or cycloalkyl groups. Non-limiting examples of suitable groups are: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, 2-methylpentyl, n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, 5-dimethylhexyl, n-nonyl, n-decyl, isodecyl, n-undecyl, n-dodecyl.

Non-limiting examples of suitable hydrocarbylaluminum compounds are as follows: triisobutylaluminum, tri-n-hexylaluminum, diisobutylaluminum hydride, di-n-hexylaluminum hydride, isobutylaluminum dihydride, n-hexylaluminum dihydride, diisobutyhexylaluminum, isobutyldihexylaluminum, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, tri-n-octylaluminum, tri-n-decylaluminum, tri-n-dodecylaluminum. In one embodiment, the preferred cocatalyst is selected from the group consisting of triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, diisobutylaluminum hydride, and di-n-hexylaluminum hydride, and the most preferred cocatalyst is triethylaluminum.

In one embodiment, the cocatalyst is represented by the formula R_nAlX_3-nThe hydrocarbylaluminum compounds of wherein n ═ 1 or 2, R is an alkyl group, and X is a halide or alkoxide. Non-limiting examples of suitable compounds are as follows: methylaluminoxane, isobutylaluminoxane, diethylaluminum ethoxide, diisobutylaluminum chloride, tetraethyldialuminoxane, tetraisobutyldialuminoxane, diethylaluminum chloride, ethylaluminum dichloride, methylaluminum dichloride and dimethylaluminum chloride.

In one embodiment, the catalyst composition comprises an external electron donor. As used herein, an "external electron donor" is a compound that is added independently of the formation of the procatalyst and contains at least one functional group capable of donating an electron pair to a metal atom. Without being bound by a particular theory, it is believed that the external electron donor enhances the catalyst stereoselectivity (i.e., reduces xylene solubles material in the derivative polymer).

In one embodiment, the external electron donor may be selected from one or more of the following: alkoxysilanes, amines, ethers, carboxylates, ketones, amides, carbamates, phosphines, phosphates, phosphites, sulfonates, sulfones, and/or sulfoxides.

In one embodiment, the external electron donor is an alkoxysilane. The alkoxysilane has the general formula: SiR_m(OR′)_4-m(I) Wherein each occurrence of R is independently hydrogen or a hydrocarbyl or amino group, optionally substituted with one or more substituents containing one or more group 14, group 15, group 16 or group 17 heteroatoms, and R' contains up to 20 atoms (hydrogen and halogen are not counted amongInner); r' is C_1-4An alkyl group; and m is 0, 1,2 or 3. In one embodiment, R is C_6-12Aryl, alkyl or aralkyl, C_3-12Cycloalkyl radical, C_3-12Branched alkyl or C_3-12A cyclic or acyclic amino group, R' is C_1-4Alkyl, and m is 1 or 2. Non-limiting examples of suitable silane compositions include dicyclopentyldimethoxysilane, di-t-butyldimethoxysilane, methylcyclohexyldimethoxysilane, methylcyclohexyldiethoxysilane, ethylcyclohexyldimethoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, di-n-propyldimethoxysilane, diisobutyldimethoxysilane, diisobutyldiethoxysilane, isobutylisopropyldimethoxysilane, di-n-butyldimethoxysilane, cyclopentyltrimethoxysilane, isopropyltrimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, ethyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, diethylaminotriethoxysilane, cyclopentylpyrrolidindimethoxysilane, bis (pyrrolidine) dimethoxysilane, bis (perhydroisoquinolino) dimethoxysilane, and dimethyldimethoxysilane. In one embodiment, the silane composition is dicyclopentyldimethoxysilane (DCPDMS), methylcyclohexyldimethoxysilane (MChDMS), diisopropyldimethoxysilane (DIPDMS), n-propyltrimethoxysilane (NPTMS), Diethylaminotriethoxysilane (DATES), or n-Propyltriethoxysilane (PTES), and any combination thereof.

In one embodiment, the external donor may be a mixture of at least 2 alkoxysilanes. In further embodiments, the mixture may be dicyclopentyldimethoxysilane and methylcyclohexyldimethoxysilane, dicyclopentyldimethoxysilane and tetraethoxysilane, or dicyclopentyldimethoxysilane and n-propyltriethoxysilane.

In one embodiment, the external electron donor is selected from one or more of the following: benzoate esters and/or glycol esters. In another embodiment, the external electron donor is 2,2, 6, 6-tetramethylpiperidine. In another embodiment, the external electron donor is a diether.

In one embodiment, the catalyst composition comprises an Activity Limiting Agent (ALA). As used herein, an "activity limiting agent" ("ALA") is a material that reduces the activity of a catalyst at elevated temperatures (i.e., temperatures above about 85 ℃). ALA suppresses or otherwise prevents a polymerization reactor from malfunctioning and ensures that the polymerization process is continuously running. Generally, as the reactor temperature increases, the activity of the Ziegler-Natta catalyst increases. Ziegler-Natta catalysts also typically maintain high activity near the melting point temperature of the polymer being produced. The heat generated by the exothermic polymerization reaction can cause the polymer particles to form agglomerates and can ultimately lead to disruption of the continuity of the polymer production process. ALA reduces catalyst activity at elevated temperatures, thereby preventing reactor upsets, reducing (or preventing) particle agglomeration, and ensuring that the polymerization process is continuously conducted.

The activity limiting agent can be a carboxylic acid ester, a diether, a poly (alkylene glycol) ester, a glycol ester, and combinations thereof. The carboxylic acid ester may be an aliphatic or aromatic monocarboxylic or polycarboxylic acid ester. Non-limiting examples of suitable monocarboxylic acid esters include ethyl and methyl benzoates, ethyl p-methoxybenzoate, methyl p-ethoxybenzoate, ethyl acrylate, methyl methacrylate, ethyl acetate, ethyl p-chlorobenzoate, hexyl p-aminobenzoate, isopropyl naphthenate, n-pentyl toluate, ethyl cyclohexanoate, and propyl pivalate.

In one embodiment, the external electron donor and/or the activity limiting agent may be added separately to the reactor. In another embodiment, the external electron donor and the activity limiting agent may be mixed together in advance and then added to the reactor as a mixture. In this mixture, more than one external electron donor or more than one activity limiting agent may be used. In one embodiment, the mixture is dicyclopentyldimethoxysilane and isopropyl myristate, dicyclopentyldimethoxysilane and poly (ethylene glycol) laurate, dicyclopentyldimethoxysilane and isopropyl myristate and poly (ethylene glycol) dioleate, methylcyclohexyldimethoxysilane and isopropyl myristate, n-propyltrimethoxysilane and isopropyl myristate, dimethyldimethoxysilane and methylcyclohexyldimethoxysilane and isopropyl myristate, dicyclopentyldimethoxysilane and n-propyltriethoxysilane and dicyclopentyldimethoxysilane and tetraethoxysilane, isopropyl myristate, n-pentyl valerate, and combinations thereof.

In one embodiment, the catalyst composition comprises any of the foregoing external electron donors in combination with any of the foregoing activity limiting agents.

The catalyst system as described above has been found to be particularly suitable for producing the heterophasic polymer composition of the present disclosure.

Due to the physical properties of the polypropylene composition of the present disclosure, in particular the flow properties of the composition, the composition is particularly suitable for the production of molded articles. For example, polypropylene compositions are useful in injection molding, blow molding and rotational molding applications.

The polypropylene polymer compositions of the present disclosure can be used to make a wide and varied range of articles and products. The polymer composition is particularly suitable for the production of storage containers due to its combination of high transparency characteristics and excellent impact resistance characteristics. The storage container may be, for example, a food package. Due to the impact resistant properties of polymers, storage containers can be used, for example, to place food items in freezers. Referring to fig. 1, for example, one embodiment of a storage container made in accordance with the present disclosure is shown. As shown, the storage container 10 includes a container portion 14 defining a hollow interior for receiving one or more items. The container portion 14 may mate with the closure 12. Closure 12 may include channels and flanges that interlock with the edges of container portion 14. According to the present disclosure, the contents of the container 10 may be viewed through the walls of the container.

In addition to food containers, various other storage containers may be manufactured in accordance with the present disclosure. For example, larger storage containers can be made using the polymer compositions of the present disclosure. For example, larger storage containers may be designed to store different items in attics, garages, or other storage facilities where temperature swings may occur.

The disclosure may be better understood with reference to the following examples.

Examples

Two different heterophasic polypropylene copolymer samples were produced according to the present disclosure and tested for various properties including impact strength and haze. Comparative examples were also produced containing lower amounts of ethylene in the second phase polymer. The above-described methods are generally used in conjunction with the above-described catalysts to prepare heterophasic copolymers. Specifically, the copolymer is produced in a dual reactor setup, where the matrix polymer is produced in a first gas phase reactor, and then the contents of the first reactor are transferred to a second gas phase reactor. Ethylene was used as comonomer. The ethylene content in the first phase polymer and the second phase polymer is controlled.

A sample of polymer pellets was produced which was injection molded into a specimen. Adding an additive package to the polymer, the additive package comprising 1000ppm of pentaerythritol tetrakis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate); 1000ppm of tris (2, 4-di-tert-butylphenyl) phosphite; 180ppm of acid scavenger (hydrotalcite); 2000ppm of glyceryl monostearate; and 4000ppm of a clarifying agent. For example, specimens are prepared according to ASTM test D4101 to produce specimens for flexural and izod impact testing.

The polymerization conditions for the three samples are as follows. Gas phase reactors are used to produce polymers.

The following polypropylene compositions were produced:

the above compositions were tested for various properties. The following results were obtained:

	sample No. 1	Sample No. 2	Sample No. 3
				Flexural modulus, MPa	970	708	721
Gardner impact strength at 0 ℃ in-lbs	300	227	246
				Gardner impact strength at-20 ℃ in-lbs	230	338	374
Haze at 1 mm%	99	42	21
				Resolution at 1 mm%	＜50	92	98
Tan. delta. Peak,. degree.C	-45，0	-105，-40，5	-100，-45，5
				Ratio of crystallinity	＜3	58.3	42.3
Average particle size	1.2	3.4	2.2

Sample No. 2 and sample No. 3 above were prepared according to the present disclosure. These samples showed significantly better impact properties at a temperature of-20 ℃.

These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. Further, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Additionally, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.