Patent Description:
In automobile compounding industry, it is very common to have shrinkage change challenges when automobile OEM want to use the formulations to produce different components or produce a component by using different equipment. There will always be small shrinkage differences due to either the component design or the total short size or even different injection equipment. Those shrinkage differences can be in the range from <NUM>% to <NUM>%. To eliminate the shrinkage difference, current practice in the market is to adjust the amount of talc or polyolefin or polypropylene in the formulation to reformulate the formulation and re-test and re-qualify it according to different shrinkage requirement. This brings extra cost, extra time and extra resource requirement. <CIT> discloses a polymer composition comprising (i) a propylene polymer comprising a polymeric nucleating agent (e.g., a vinyl compound), and (ii) a heterophasic propylene polymer which comprises less (e.g., no) polymeric nucleating agent.

There is still a need for a new composition or process to prepare a component having suitable shrinkage rate with reduced cost and time.

In a first general aspect, this disclosure provides a composition comprising a first propylene-based polymer and a second propylene-based polymer, wherein the shrinkage rate of the first propylene-based polymer is higher than the shrinkage rate of the second propylene-based polymer by at least <NUM>%, based on the shrinkage rate of the second propylene-based polymer, wherein the shrinkage rate is measured as disclosed herein, and wherein the first propylene-based polymer and the second propylene-based polymer are both impact copolymers (ICP).

In a second general aspect, this disclosure provides a process for making a component, comprising the steps of:.

Certain aspects of the first, and second general aspects may include one or more of the following features.

In some aspects, the shrinkage rate of the first propylene-based polymer is higher than the shrinkage rate of the second propylene-based polymer by at least <NUM>%, preferably by at least <NUM>%, more preferably by at least <NUM>%, based on the shrinkage rate of the second propylene-based polymer.

In some aspects, the first and the second propylene-based polymers satisfy the following: (i) the difference in the notched izod impact strength between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, preferably no more than <NUM>%, based on the lower notched izod impact strength, wherein the notched izod impact strength is tested according to ISO180 at <NUM>; and (ii) the difference in flexural modulus between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, preferably no more than <NUM>%, based on the lower flexural modulus, wherein the flexural modulus is tested at <NUM>/min strain rate according to ISO178.

In some aspects, the first and the second propylene-based polymers satisfy at least one of the following: (i) the difference in melt flow rate of the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, preferably no more than <NUM>%, based on the lower melt flow rate, wherein the melt flow rate is determined according to ASTM D1238 at <NUM> and <NUM>; (ii) the difference in the tensile strength at yield between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, preferably no more than <NUM>%, based on the lower tensile strength at yield, wherein the tensile strength at yield is tested according to ISO527 at <NUM>; and (iii) the difference in the tensile stress at yield between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, preferably no more than <NUM>%, based on the lower tensile stress at yield, wherein the tensile stress at yield is tested according to ISO527 at <NUM>.

In some aspects, the first and the second propylene-based polymers satisfy at least one of the following: (i) the difference in the notched izod impact strength between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, preferably more than <NUM>%, based on the lower notched izod impact strength, wherein the notched izod impact strength is tested according to ISO180 at <NUM>; and (ii) the difference in flexural modulus between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, preferably more than <NUM>%, based on the lower flexural modulus, wherein the flexural modulus is tested at <NUM>/min strain rate according to ISO178.

In some aspects, the first and the second propylene-based polymers satisfy at least one of the following: (i) the difference in melt flow rate of the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, preferably more than <NUM>%, based on the lower melt flow rate, wherein the melt flow rate is determined according to ASTM D1238 at <NUM> and <NUM>; and (ii) the difference in the tensile strength at yield between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, preferably more than <NUM>%, based on the lower tensile strength at yield, wherein the tensile strength at yield is tested according to ISO527 at <NUM>; and (iii) the difference in the tensile stress at yield between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, preferably more than <NUM>%, based on the lower tensile stress at yield, wherein the tensile stress at yield is tested according to ISO527 at <NUM>.

The first propylene-based polymer and the second propylene-based polymer are both impact copolymers (ICP).

In some aspects, the ICP as the first propylene-based polymer comprises a polypropylene homopolymer and within the range of from <NUM> to <NUM> wt% of a propylene copolymer based on the weight of the ICP, wherein the propylene copolymer comprises from <NUM> to <NUM> wt% ethylene and/or C<NUM> to C<NUM> α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer.

In some aspects, the ICP as the second propylene-based polymer comprises a polypropylene homopolymer and within the range of from <NUM> to <NUM> wt% of a propylene copolymer based on the weight of the ICP, wherein the propylene copolymer comprises from <NUM> to <NUM> wt% ethylene and/or C<NUM> to C<NUM> α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer.

In some aspects, the propylene copolymer is an ethylene-propylene copolymer present in an amount of <NUM> to <NUM> wt%, based on the weight of ICP as the second propylene-based polymer.

In some aspects, ethylene-propylene copolymer comprises <NUM> to <NUM> wt% ethylene-derived units, based on the weight of ethylene-propylene copolymer.

In some aspects, the weight ratio of the first propylene-based polymer to the second propylene-based polymer is in the range from <NUM>:<NUM> to <NUM>:<NUM>.

In some aspects, the composition further comprises at least one component selected from polyolefin plastomers, polyolefin elastomer and filler.

In some aspects, the total content of the first propylene-based polymer and the second propylene-based polymer is in the range from <NUM> to <NUM> wt%, preferably from <NUM> to <NUM> wt%, based on the weight of the composition.

In the second aspect, step (c) comprises increasing the weight ratio of the first propylene-based polymer to the second propylene-based polymer when the shrinkage rate of the component in step (b) is lower than the target shrinkage rate.

In the second aspect, step (c) comprises decreasing the weight ratio of the first propylene-based polymer to the second propylene-based polymer when the shrinkage rate of the component in step (b) is higher than the target shrinkage rate.

Various specific embodiments, versions, and examples are described herein; including exemplary embodiments and definitions that are adopted for purposes of understanding the claimed invention. While the following detailed description gives specific preferred embodiments, those skilled in the art will appreciate that these embodiments are exemplary only and that the invention can be practiced in other ways. For purposes of determining infringement, the scope of the invention will refer to any one or more of the appended claims, including their equivalents, and elements or limitations that are equivalent to those that are recited. Any reference to the "invention" may refer to one or more, but not necessarily all, of the inventions defined by the claims.

As used herein, the term "copolymer" is meant to include polymers having two or more monomers, optionally, with other monomers, and may refer to interpolymers, terpolymers, etc. The term "polymer" as used herein includes, but is not limited to, homopolymers, copolymers, terpolymers, etc., and alloys thereof. The term "polymer" as used herein also includes impact, block, graft, random, and alternating copolymers. The term "polymer" shall further include all possible geometrical configurations unless otherwise specifically stated. Such configurations may include isotactic, syndiotactic and atactic symmetries.

"Propylene-based", as used herein, is meant to include any polymer comprising propylene, either alone or in combination with one or more comonomers, in which propylene is the major component (i.e., greater than <NUM> wt% propylene).

All numerical values within the detailed description and the claims herein are modified by "about" the indicated value, and take into account experimental error and variations that would be expected by those skilled in the art.

The shrinkage rate can be tested as follows:.

The shrinkage rate is the average of flow/cross flow direction. The shrinkage rate reported for each material is the average shrinkage rate of four sample bars prepared under above mentioned four different holding pressure.

For example, the shrinkage rate can be tested by Shrink Plaque Checking Fixture (Manufacturer: U-Micro tooling Co.

In the present invention, the shrinkage rate of the first propylene-based polymer is higher than the shrinkage rate of the second propylene-based polymer by at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, or at least <NUM>%, based on the shrinkage rate of the second propylene-based polymer. Usually, the shrinkage rate of the first propylene-based polymer is higher than the shrinkage rate of the second propylene-based polymer by no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>% , based on the shrinkage rate of the second propylene-based polymer.

In one embodiment, the first propylene-based polymer and the second propylene-based polymer have similar physical properties, such as notched izod impact strength, flexural modulus, melt flow rate, tensile strength at yield and/or tensile stress at yield. They are called as twin propylene-based polymers. By using these propylene-based polymers, the compounder can easily adjust the shrinkage rate of the component with its physical properties keeping unchanged.

In one embodiment, the difference in the notched izod impact strength between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, or no more than <NUM>%, based on the lower notched izod impact strength. The notched izod impact strength is tested according to ISO180 at <NUM>.

In one embodiment, the difference in flexural modulus between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, or no more than <NUM>%, based on the lower flexural modulus. The flexural modulus is tested at <NUM>/min strain rate according to ISO178.

In one embodiment, the difference in melt flow rate (MFR) of the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, or no more than <NUM>%, based on the lower melt flow rate. MFR is determined according to ASTM D1238, at <NUM> and <NUM>.

In one embodiment, the difference in the tensile strength at yield between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, or no more than <NUM>%, based on the lower tensile strength at yield. The tensile strength at yield is tested according to ISO527 at <NUM>.

In one embodiment, the difference in the tensile stress at yield between the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, no more than <NUM>%, or no more than <NUM>%, based on the lower tensile stress at yield. The tensile stress at yield is tested according to ISO527 at <NUM>.

In one embodiment, the first and the second propylene-based polymers satisfy at least one, preferably at least two, more preferably at least three, most preferably all of the following: the difference in (i) notched izod impact strength, (ii) flexural modulus, (iii) melt flow rate and (iv) tensile strength at yield (or tensile stress at yield) of the first propylene-based polymer and the second propylene-based polymer is no more than <NUM>%, no more than <NUM>%, or no more than <NUM>%, in each case based on the lower value.

In one embodiment, the first propylene-based polymer and the second propylene-based polymer have different physical properties, such as at least one of notched izod impact strength, flexural modulus, melt flow rate, tensile strength at yield and tensile stress at yield. They are called as partner propylene-based polymers. By using these propylene-based polymers, the compounder can easily adjust the shrinkage rate of the component and change the physical properties of the component at the same time.

In one embodiment, the difference in the notched izod impact strength between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, or more than <NUM>%, based on the lower notched izod impact strength.

In one embodiment, the difference in flexural modulus between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, or more than <NUM>%, based on the lower flexural modulus.

In one embodiment, the difference in melt flow rate of the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, or more than <NUM>%, based on the lower melt flow rate.

In one embodiment, the difference in the tensile strength at yield between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, or more than <NUM>%, based on the lower tensile strength at yield.

In one embodiment, the difference in the tensile stress at yield between the first propylene-based polymer and the second propylene-based polymer is more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, more than <NUM>%, or more than <NUM>%, based on the lower tensile stress at yield.

The first propylene-based polymer and the second propylene-based polymer are both ICP.

The propylene copolymer can be copolymers of propylene and ethylene or C4 to C10 α-olefins.

ICP comprises a polypropylene homopolymer and within a range of from <NUM> or <NUM> or <NUM>, or <NUM>, or <NUM> wt% to <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM> wt% of propylene copolymer based on the weight of the ICP, wherein the propylene copolymer comprises from <NUM>, or <NUM>, or <NUM>, or <NUM> wt% to <NUM> or <NUM>, or <NUM>, or <NUM> or <NUM> wt% ethylene and/or C<NUM> to C<NUM> α-olefin (for example <NUM>-butene, <NUM>-hexene, and/or <NUM>-octene) derived units and from <NUM> to <NUM> wt% propylene-derived units based on the weight of the propylene copolymer. The propylene copolymer is imbedded in a continuous phase of polypropylene homopolymer.

The ICP can have an MFR (<NUM>/<NUM> ASTM D1238) of at least <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>/<NUM>, or within a range from <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>/<NUM> to <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>/<NUM>. The ICP typically has a heat deflection temperature (HDT) (<NUM> MPa) within a range from <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM> to <NUM>, or <NUM>, or <NUM>. The HDT can be tested according to ISO <NUM>. The ICP can have a flexural modulus of at least <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM> or <NUM> MPa, or within a range from <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM> MPa to <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM> MPa. The ICP can have a notched Izod impact strength of at least <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM> kJ/m<NUM>.

In one embodiment, the ICP as the first propylene-based polymer comprises a polypropylene homopolymer and within the range of from <NUM> to <NUM> wt%, preferably from <NUM> to <NUM> wt% of a propylene copolymer based on the weight of the ICP, wherein the propylene copolymer comprises from <NUM> to <NUM> wt%, preferably from <NUM> to <NUM> wt% ethylene and/or C<NUM> to C<NUM> α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer.

In one embodiment, the ICP as the second propylene-based polymer comprises a polypropylene homopolymer and within the range of from <NUM> to <NUM> wt%, preferably from <NUM> to <NUM> wt% of a propylene copolymer based on the weight of the ICP, wherein the propylene copolymer comprises from <NUM> to <NUM> wt% ethylene and/or C<NUM> to C<NUM> α-olefin derived units and the remainder propylene-derived units based on the weight of the propylene copolymer. This ICP can have an MFR (<NUM>/<NUM> ASTM D1238) within a range from <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>/<NUM> to <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>/<NUM>. The propylene copolymer can be an ethylene-propylene copolymer present in an amount of <NUM> to <NUM> wt%, based on the weight of ICP as the second propylene-based polymer. The ethylene-propylene copolymer can comprise <NUM> to <NUM> wt%, preferably <NUM> to <NUM> wt% ethylene-derived units, based on the weight of the ethylene-propylene copolymer.

The ICPs suitable for use in the present invention may be prepared by conventional polymerization techniques. For example, the ICP may be produced using a two-step gas phase process using Ziegler-Natta catalysis, an example of which is described in <CIT>.

The ICPs described herein can also be produced in series reactors wherein the polypropylene homopolymer is first produced in one or more slurry reactors by contacting a catalyst and monomers, preferably propylene, such as in slurry-loop reactors well known in the art, followed by combining the same catalyst and formed homopolymer in a single gas-phase reactor with monomers, preferably propylene and ethylene and/or C<NUM> to C<NUM> α-olefins, to produce the propylene copolymer such that the copolymer imbeds itself in the homopolymer as discrete domains with the homopolymer as a matrix or "continuous" phase. The MFR of the individual components can be controlled by, for example, addition and removal of hydrogen from the reactors. Most preferably, the homopolymer is produced in two loop-slurry reactors in series and each as a similar or same amount of hydrogen, producing homopolymer of nearly the same or the same MFR. The amount of hydrogen in the gas phase reactor may be the same or different from the loop slurry reactor, such level controlled by removing the hydrogen from the homopolymer stream entering the gas phase reactor or at some other stage. A suitable process and apparatus are described in <CIT> and <CIT> (column <NUM>, line <NUM> to column <NUM>, line16). The systems and processes disclosed therein can be used in a "balanced" reactor scheme where two slurry loop reactors in series forming the polypropylene homopolymer are under the same or similar conditions, followed by transfer of the crystalline polymer (polypropylene homopolymer) to a single gas phase reactor to form the semi-crystalline polymer (propylene copolymer).

In one embodiment, the ICP is prepared by using a Ziegler-Natta catalyst system with a blend of electron donors as described in <CIT> or <CIT>. In one embodiment, the ICP may be prepared using a succinate Ziegler-Natta type catalyst system.

Metallocene-based catalyst systems may also be used to produce the ICP described herein. Current particularly suitable metallocenes are those in the generic class of bridged, substituted bis(cyclopentadienyl) metallocenes, specifically bridged, substituted bis(indenyl) metallocenes known to produce high molecular weight, high melting, highly isotactic propylene polymers. Generally speaking, those of the generic class disclosed in <CIT> are suitable.

In one embodiment, the weight ratio of the first propylene-based polymer to the second propylene-based polymer can be in the range from <NUM>:<NUM>, or <NUM>:<NUM>, or <NUM>:<NUM>, or <NUM>:<NUM> to <NUM>:<NUM>, or <NUM>:<NUM>, or <NUM>:<NUM>, or <NUM>:<NUM>.

A further aspect of the present invention is directed to a composition comprising the combination of the present invention.

The total content of the first propylene-based polymer and the second propylene-based polymer can be in the range from <NUM>, or <NUM>, or <NUM>, or <NUM> to <NUM>, or <NUM>, or <NUM>, or <NUM> wt%, preferably from <NUM> to <NUM> wt%, based on the weight of the composition.

The composition of the present invention can further comprise other polymeric materials and common additives. Desirable polymeric materials include polyolefin plastomers, such as polypropylene homopolymers, polyethylenes (LLDPE, HDPE, LDPE); polyolefin elastomer, such as propylene-based elastomers, elastomers such as EP rubber, EPDM, ethylene-butene copolymer elastomers, butyl rubber, styrenic copolymers and block copolymers, and other impact copolymers, especially so called "high-comonomer" impact copolymers, which are defined as propylene-based impact copolymers having greater than <NUM> wt% comonomer-derived units in the copolymer portion. Common "additives" include fillers such as talc, carbon black, clay, silica, fatty acids, and other well-known materials, as well as antioxidants, anti-slip agents, pigments, cavitating agents (e.g., calcium carbonate), nucleating agents, curatives for added polymers that are curable, and any other of one or more well-known additives.

In one embodiment, the composition further comprises at least one component selected from polyolefin plastomers, polyolefin elastomer and filler.

Usually, the content of the other polymeric material such as polyolefin plastomers and polyolefin elastomer is less than <NUM> wt%, or less than <NUM> wt%, or within the range from <NUM> wt%, or <NUM> to <NUM> wt%, or <NUM> wt%, based on the weight of the composition.

The content of filler, such as the talc can be in the range from <NUM> to <NUM> wt%, or from <NUM> to <NUM> wt%, or from <NUM> to <NUM> wt%.

In one embodiment, the first propylene-based polymer and the second propylene-based polymer in the composition are both ICP and the composition comprises a further ICP, a polyolefin elastomer, such as ethylene-butene copolymer and a filler such as talc.

In one embodiment, the further ICP comprises a polypropylene homopolymer and within the range of from <NUM> to <NUM> wt% of a propylene copolymer based on the weight of the ICP and the propylene copolymer comprises greater than <NUM> wt% ethylene-derived units based on the weight of the propylene copolymer.

These polymeric materials and additives may be compounded with the polypropylene-based polymer by traditional blending such as in a Brabender mixer, or extruded in a single or double screw extruder.

A further aspect of the present disclosure is directed to a component comprising the composition of the present invention.

The composition described herein is suitable for use in processes such as injection molding, blow molding and thermoforming for making useful articles for automotives and appliances. In particular, the inventive composition can be formed into automotive components, either alone or in a mixture with other polymers, exemplary components can include the interior dashboard, interior side trim, handles, interior door facing and components, exterior bumpers, wheel trim, and various fascia used for decorative purposes.

A further aspect of the present invention is directed to a process for making a component, comprising the steps of:.

In one embodiment, step (c) comprises increasing the weight ratio of the first propylene-based polymer to the second propylene-based polymer when the shrinkage rate of the component in step (b) is lower than the target shrinkage rate.

In one embodiment, step (c) comprises decreasing the weight ratio of the first propylene-based polymer to the second propylene-based polymer when the shrinkage rate of the component in step (b) is higher than the target shrinkage rate.

A further aspect of the present disclosure is directed to a propylene-based impact copolymer (ICP) comprising a polypropylene homopolymer and within the range of from <NUM> to <NUM> wt% of a propylene copolymer based on the weight of the ICP, wherein the propylene copolymer is an ethylene-propylene copolymer comprising from <NUM> to <NUM> wt%, preferably from <NUM> to 40wt% ethylene-derived units and the remainder propylene-derived units, based on the weight of the propylene copolymer. The content of polypropylene in this ICP can be in the range from <NUM> to <NUM> wt%, based on the weight of the ICP.

In one embodiment, the shrinkage rate of the ICP is less than <NUM>%, preferably less than <NUM>%, or less than <NUM>%.

In one embodiment, the ICP has at least one of the following properties: (i) a melt flow rate (MFR) (<NUM>/<NUM>, ASTM D1238) of <NUM> to <NUM>/<NUM>, (ii) an MFR of the polypropylene homopolymer of <NUM> to <NUM>/<NUM>, and (iii) an intrinsic viscosity of the propylene copolymer of <NUM> to <NUM> dL/g. The intrinsic viscosity can be measured according to ISO <NUM>-<NUM>:<NUM>.

The ICP can further comprises a filler in an amount of from <NUM> to <NUM> wt%, preferably from <NUM> to <NUM> wt%, based on the total weight of ICP.

The filler can be talc, glass, and other minerals.

The ICP in this further aspect can be prepared as follows:.

The "amino-silane" donor is an external electron donor having at least one amine or alkylamine moiety and at least one silane, alkylsilane or siloxane moiety.

The ICP in the further aspect of the present disclosure has low shrinkage rate and good mechanical performance and can be used as the second propylene-based polymer.

The combination, the composition comprising the combination and the process according to the present invention enable the compounder to produce the component having the desired shrinkage rate with reduced cost and time in a very simple way. Meanwhile, the present invention enables the compounder to maintain the mechanical properties, such as notched izod impact strength, flexural modulus, melt flow rate, tensile strength and/or tensile stress, especially notched izod impact strength and flexural modulus of the component when adjusting the shrinkage rate by using two propylene-based polymers having similar mechanical properties, or change the above mentioned mechanical properties of the component when adjusting the shrinkage rate by using two propylene-based polymers having different mechanical properties.

ICP 1P: containing <NUM> wt% polypropylene homopolymer (PP), and <NUM> wt% ethylene-propylene copolymer (EP) having <NUM> wt% ethylene-derived unit; the shrinkage rate is <NUM>%; ICP 2P: containing <NUM> wt% PP, and <NUM> wt% EP having <NUM> wt% ethylene-derived unit; the shrinkage rate is <NUM>%;.

The properties of ICPs and testing method are summarized in the following table <NUM>:.

Methodology: Shrinkage rate is calculated according to following equation: <MAT> wherein L<NUM> is the size of mold cavity and L<NUM> is the size of sample bar.

The sample bars are prepared by Injection Molding Machine (Type: DEMAG Multi <NUM>/<NUM> --<NUM>/80v) according to ASTM standard D4101 at <NUM>. Four different holding pressure, i.e. <NUM> MPa, 30MPa, 40MPa and <NUM> MPa are used for each material in the to produce four sample bars, wherein holding pressure is the pressure that holds the material feed after the material has been injected into mold cavity. The size of the mold cavity for preparing the sample bar is <NUM>*<NUM> and the thickness of the sample bar is <NUM>. The sample bars are conditioned at <NUM>±<NUM> for <NUM> hours before testing. The shrinkage rate test is taken under the same condition of <NUM>±<NUM>.

The equipment used for testing shrinkage is Shrink Plaque Checking Fixture (Manufacturer: U-Micro tooling Co. ) (see <FIG>).

<NUM> tests are carried out for each sample bar. The shrinkage rate is the average of flow/cross flow direction. The shrinkage rate reported for each material is the average shrinkage rate of four sample bars prepared under above mentioned four different holding pressure.

Propylene was combined with an amino-silane donor, diethylamino-triethoxysilane, <NUM> mppm hydrogen (relative to the propylene and other olefins), and <NUM> ppm titanium/magnesium-based Ziegler-Natta catalyst (relative to the propylene and other olefins) in a slurry-type polymerization reactor (flow loop reactor). The polypropylene was produced in a series of two continuous flow loop reactors. The amino-silane donor was present at <NUM> ppm, an aluminum alkyl (triethylaluminum) was present at <NUM> ppm (relative to the propylene and other olefins), and the components were combined at a temperature of <NUM> and pressure of <NUM> psig (<NUM> MPa). The loop reactor pressure and temperature were maintained such that the system remained at or below the bubble point. The residence time in the first loop reactor is about <NUM> and the residence time in the second loop reactor is about <NUM>.

The polypropylene that was produced in the loop reactors was then transferred to a downstream gas phase reactor (GPR) to add an ethylene-propylene copolymer to produce the final impact copolymer product. Hydrogen was removed from the polypropylene containing slurry by a cycling pressure method prior to re-pressurizing and entering the GPR. The pressure in the GPR is <NUM> KPaG and the residence time in the GPR is about <NUM>. The temperature of GPR is controlled to about <NUM> for low odor. Finally, <NUM> ppm talc is added to obtain ICP 2T.

The ICPs, talc and POE are fed to a twin-screw extruder (Leistritz Twin--screw extruder ZSE <NUM> HP) via different hopper. The amounts of ICPs, talc and POE are shown in table <NUM>. The extruder is operated at <NUM>. An underwater pelletizing system is used to cut and prepare the final pellets. The shrinkage rate of each composition tested according to the above method are also shown in table <NUM> and <FIG>.

According to our results shown in table <NUM>, by changing the ratio between ICP 1P and ICP 2P, the shrinkage rate can vary from <NUM> to <NUM>, which is a <NUM>% flexibility range. This provides good flexibility to adjust the shrinkage rate of the components.

The ICPs, talc and POE are fed to a twin-screw extruder (Leistritz Twin--screw extruder ZSE <NUM> HP) via different hopper. The amounts of ICPs, talc and POE are shown in table <NUM>. The extruder is operated at <NUM>. An underwater pelletizing system is used to cut and prepare the final pellets. The shrinkage rate of each composition tested according to the above method are also shown in table <NUM>.

Claim 1:
A composition comprising a first propylene-based polymer and a second propylene-based polymer, wherein the shrinkage rate of the first propylene-based polymer is higher than the shrinkage rate of the second propylene-based polymer by at least <NUM>%, preferably by at least <NUM>%, preferably by at least <NUM>%, more preferably by at least <NUM>%, based on the shrinkage rate of the second propylene-based polymer, wherein the shrinkage rate is measured as disclosed herein, and wherein the first propylene-based polymer and the second propylene-based polymer are both impact copolymers (ICP).