Polyolefin blend and cutting tape backing film

Abstract

This invention relates to polypropylene blends comprising a propylene-based elastomer and a propylene copolymer, wherein the propylene-based elastomer comprises at least 60 wt% propylene-derived units and 1 to 35 wt% of at least one type selected from ethylene and C4-C4 copolymers. 20 The unit is derived from the comonomer of an α-olefin, based on the total weight of the propylene-based elastomer, wherein the heat of melt of the propylene-based elastomer is less than 80 J / g, and wherein the propylene copolymer is propylene and at least one copolymer selected from ethylene and C4-C4. 20 Copolymers of α-olefin comonomers, with a weight-average molecular weight ranging from greater than 8000 g / mol, or greater than 10000 g / mol, or greater than 12000 g / mol, or greater than 20000 g / mol to less than 1,000,000 g / mol, or less than 800,000 g / mol.

Description

Technical Field

[0001] The disclosure of this application relates to polypropylene blends comprising propylene-based elastomers and propylene copolymers; and the resulting cut-band backing film. Background Technology

[0002] Dicing tape is a special adhesive tape used in semiconductor wafer dicing processes. This tape firmly holds the wafer in place and maintains stability during dicing, preventing movement or damage. Dicing tape plays a crucial role in the manufacture of integrated circuits and other semiconductor devices because it helps ensure precise cut dimensions and shapes, such as… Figure 6 As shown.

[0003] The dicing tape can be made of materials such as polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyolefin backing material, and adhesive to hold the wafer or substrate in place. In some cases, the dicing tape has a release liner that is removed before the dicing tape is mounted onto the back side of the wafer, and has various adhesive strengths designed for various wafer sizes and materials.

[0004] PVC and PET are commonly used as backing materials for cutting tapes. PVC exhibits excellent performance in terms of colorability, processability, scratch resistance, and weather resistance. Plasticizers are added to PVC to impart flexibility because the inherent rigidity of PVC film can easily cause damage during wafer grinding. However, depending on the plasticizer used, problems include poor compatibility with adhesives, poor stability of the adhesive film, and significant plasticizer leakage. PET also has high stiffness and tends to cause warping problems.

[0005] CN113811565B discloses a substrate film for cutting tape that combines heat resistance and isotropy. The substrate comprises (1) linear low-density polyethylene; and (2) block polypropylene copolymerized with ethylene or homopolymer polypropylene polymerized by polymerizing propylene alone. The substrate film has a storage modulus (E′) of 20–200 MPa at 100°C, stresses (at 100% elongation) in the MD and TD directions of 5 MPa or more and less than 20 MPa, and a thickness of 50–300 μm. However, compared to polypropylene resins, polyethylene resins have a lower melting point, and therefore still suffer from a lack of heat resistance and thermal deformation during exothermic processes such as high-temperature cutting or grinding of wafers.

[0006] JP4916290B2 provides a substrate film for dicing, characterized by minimal residual debris during the dicing process of semiconductor wafers, reducing waste, and exhibiting excellent static charge removal properties. This technical solution primarily utilizes multiple components such as styrene-butadiene copolymer (SEBS) and polypropylene resin (PP). However, due to the significant differences in the chemical structures of SEBS and PP, defects in formulation compatibility and performance stability are easily caused.

[0007] JP2008153586A also provides a cutting substrate film for reducing residual debris during the cutting process of the base film, but there is still room for further optimization in terms of the comprehensive improvement of other key properties of the base film and the uniformity of transverse and longitudinal properties.

[0008] WO2020218468A1 primarily proposes a solution based on polypropylene and polyolefin elastomers to address the requirements for the flexibility and optical properties of the base film. This solution requires an internal turbidity of less than 20%, a gloss level of less than 40% on at least one side, and a tensile modulus of elasticity in the machine direction of less than 600 MPa. However, there is still room for further optimization in terms of the comprehensive improvement of other key properties of the base film, as well as the uniformity of transverse and longitudinal properties.

[0009] JP6472972B2 and CN114603961A also report resin compositions for producing dicing tape substrates and protective film substrates for cutting integrated circuit packaging substrates, respectively. The former uses multiple components such as ethylene α,β-unsaturated carboxylic acid copolymers, multi-component copolymers, and polyolefins. The latter uses multiple components such as low-density polyethylene, metallocene linear low-density polyethylene, ethylene-vinyl acetate copolymers and / or polyethylene elastomers, nano-zinc oxide, coupling agents, and diluents. The formulations are complex, and there are significant differences in chemical structure and compatibility issues among the components, which can easily cause fluctuations and anisotropy in the performance of the base film.

[0010] Therefore, there is still a need in the art for cutting tape backing films with improved performance, especially cutting tape backing films with good compatibility, tensile strength, flexibility, elongation, tear strength and excellent optical properties.

[0011] Technology Development

[0012] Polyolefin-based films are a new type of base film made from polyolefin copolymers, exhibiting good light transmittance, a soft texture, a waterproof surface, and limited small molecule deposits to ensure wafer-level cleanliness. Simultaneously, the softness of the film facilitates good compatibility with wafer processing, absorbing some of the machine vibrations during the dicing process. Compared to PE films, these films offer better heat resistance, making them suitable for the high-temperature conditions of adhesive coating and drying processes. The excellent tensile properties and abrasion resistance of the polyolefin matrix also make it a strong alternative to traditional backing materials.

[0013] The technical problem to be solved by this invention:

[0014] Therefore, this invention was made in view of the above-mentioned problems, and its object is to provide a substrate film solution based on a casting process. By adding a propylene-based elastomer, such as the propylene-based elastomer provided by the brand name Vistamaxx, to the propylene random copolymer system, the compatibility of the components can be greatly improved. Simultaneously, while reducing the thickness of the base film, the overall performance of the base film in multiple key indicators such as flexibility, tensile properties, and elongation is enhanced. Furthermore, excellent light transmittance is maintained, while balancing transverse and longitudinal properties. These properties are crucial for dicing applications. Summary of the Invention

[0015] In one embodiment, the present invention provides a polypropylene blend comprising a propylene-based elastomer and a propylene copolymer, wherein the propylene-based elastomer comprises at least 60 wt% propylene-derived units and 1 to 35 wt% of at least one compound selected from ethylene and C4-C4 copolymers. 20 The unit is derived from the comonomer of an α-olefin, based on the total weight of the propylene-based elastomer, wherein the heat of melt of the propylene-based elastomer is less than 80 J / g, the melting point of the propylene-based elastomer is less than or equal to 105°C, and wherein the propylene copolymer is propylene and at least one selected from ethylene and C4-C 20 Copolymers of α-olefin comonomers, with a weight-average molecular weight ranging from greater than 8000 g / mol, or greater than 10000 g / mol, or greater than 12000 g / mol, or greater than 20000 g / mol to less than 1,000,000 g / mol, or less than 800,000 g / mol.

[0016] In another embodiment, the present invention provides a cutting strip backing film obtained from the above-described polypropylene blend.

[0017] The present invention also relates to the following embodiments:

[0018] 1. A polypropylene blend comprising a propylene-based elastomer and a propylene copolymer, wherein the propylene-based elastomer comprises at least 60 wt% propylene-derived units and 1 to 35 wt% of at least one compound selected from ethylene and C4-C4 copolymers. 20 The unit is derived from the comonomer of an α-olefin, based on the total weight of the propylene-based elastomer, wherein the heat of melt of the propylene-based elastomer is less than 80 J / g, the melting point of the propylene-based elastomer is less than or equal to 105°C, and wherein the propylene copolymer is propylene and at least one selected from ethylene and C4-C 20 Copolymers of α-olefin comonomers, with a weight-average molecular weight ranging from greater than 8000 g / mol, or greater than 10000 g / mol, or greater than 12000 g / mol, or greater than 20000 g / mol to less than 1,000,000 g / mol, or less than 800,000 g / mol.

[0019] 2. The polypropylene blend according to embodiment 1, wherein the content of propylene-derived units in the propylene-based elastomer is from a lower limit of 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 84 wt%, 85 wt% to an upper limit of 85 wt%, 90 wt%, 92 wt%, 94 wt%, 95 wt%.

[0020] 3. The polypropylene blend according to any one of the above embodiments, wherein at least one of the propylene-based elastomers is selected from ethylene and C4-C4. 20 The content of the comonomer-derived units of the α-olefin is 5-35 wt%, or 7-30 wt%, or 8-25 wt%, or 8-20 wt%, or 8-18 wt%.

[0021] 4. The polypropylene blend according to any one of the above embodiments, wherein the crystallinity of the propylene-based elastomer is 2% to 65% of the crystallinity of isotactic polypropylene.

[0022] 5. The polypropylene blend according to any one of the above embodiments, wherein the graded melt flow rate (MFR) of the propylene-based elastomer is 2-20 g / 10 min.

[0023] 6. The polypropylene blend according to any one of the above embodiments, wherein at least one of the propylene-based elastomers is selected from ethylene and C4-C4. 20 The comonomer of the α-olefin is selected from ethylene, 1-hexene or 1-octene, with ethylene being preferred.

[0024] 7. The polypropylene blend according to any one of the above embodiments, wherein the heat of melt of the propylene-based elastomer is from a lower limit of 1.0 J / g, 1.5 J / g, 3.0 J / g, 4.0 J / g, 6.0 J / g to an upper limit of 35 J / g, 40 J / g, 50 J / g, 60 J / g, 70 J / g, 75 J / g, 80 J / g.

[0025] 8. The polypropylene blend according to any one of the above embodiments, wherein the propylene-based elastomer may further comprise diene-derived units.

[0026] 9. The polypropylene blend according to embodiment 8, wherein the diene is selected from 1,4-hexadiene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,7-cyclododecadiene, tetrahydroindene, norbornene, methyl-tetrahydroindene, cyclopentadiene, bicyclo-(2.2.1)-hept-2,5-diene, alkenyl norbornene, Ethylidene norbornene, 5-methylene-norbornene, 5-ethylidene-2-norbornene, 5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene, vinylcyclohexene, allylcyclohexene, vinylcyclooctene, 4-vinylcyclohexene, allylcyclodecene, vinylcyclododecene.

[0027] 10. The polypropylene blend according to embodiment 8, wherein the content of the propylene-based elastomeric diene-derived unit ranges from a lower limit of 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.5 wt%, 1 wt%, 3 wt%, 5 wt% to an upper limit of 1.5 wt%, 2.5 wt%, 3 wt%, 4.5 wt%, 5 wt%, 7 wt%, 10 wt%, 15 wt%.

[0028] 11. The polypropylene blend according to any one of the above embodiments, wherein the content of the propylene-based elastomer is 6 wt% to 30 wt%, 10 wt% to 30 wt%, or 10 wt% to 25 wt%, based on the total weight of the polypropylene blend.

[0029] 12. The polypropylene blend according to any one of the above embodiments, wherein the content of the propylene copolymer is 70 wt% to 94 wt%, 70 wt% to 90 wt%, or 75 wt% to 90 wt%, based on the total weight of the polypropylene blend.

[0030] 13. The polypropylene blend according to any one of the above embodiments, wherein the polypropylene blend is in the form of a single-layer film or a multilayer film.

[0031] 14. The polypropylene blend according to any one of the above embodiments, wherein the 1% secant flexural modulus of the propylene copolymer is 100 MPa to 2300 MPa, preferably 200 MPa to 2100 MPa, more preferably 300 MPa to 2000 MPa and most preferably 400 MPa to 1800 MPa.

[0032] 15. The polypropylene blend according to any one of the above embodiments, wherein the melt flow rate (MFR) of the propylene copolymer is from 0.1 dg / min to 2500 dg / min, preferably from 0.3 dg / min to 500 dg / min.

[0033] 16. A cut-band backing film comprising a polypropylene blend according to any one of the above embodiments.

[0034] 17. Use of the polypropylene blend according to any one of embodiments 1-15 in integrated circuits, chips, and semiconductor materials.

[0035] 18. A polypropylene blend comprising a propylene-based elastomer and a propylene copolymer, wherein the propylene-based elastomer has a weight-average molecular weight of 100,000 to 300,000 g / mol, a melt flow rate of 2.5 g / 10 min to 10 g / 10 min at 230 °C and 2.16 kg according to ASTM 1238, and a density of 0.85 g / cm³ according to ASTM D-1505. 3 Up to 0.88 g / cm 3 The content is 6 wt% to 30 wt%, based on the total weight of the polypropylene blend, wherein the propylene copolymer is prepared using a catalyst system comprising an activator and a quinolinyl diamino catalyst or a group 4 bis(phenolate) complex, and contains 4 to 16 wt% ethylene with a content of 70 wt% to 94 wt%, based on the total weight of the polypropylene blend. Attached Figure Description

[0036] Figure 1 The 1% secant modulus of commercially available products and blends prepared in the technical solution of this invention is shown.

[0037] Figure 2 The tensile strength of commercially available products and blends prepared in the technical solution of this invention is demonstrated.

[0038] Figure 3 The elongation at break of commercially available products and blends prepared in the technical solution of this invention are shown.

[0039] Figure 4 The Elmandorf tear of the blend prepared in the technical solution of the present invention is shown.

[0040] Figure 5 The optical properties of the blends prepared in the technical solution of this invention are demonstrated.

[0041] Figure 6 This is a schematic diagram involving semiconductor cutting. Invention Details

[0042] Before disclosing and describing the compounds, components, compositions, and / or methods of the present invention, it should be understood that, unless otherwise stated, the invention is not limited to specific compounds, components, compositions, reactants, reaction conditions, ligands, metallocene structures, catalyst structures, or the like, as these can be varied unless otherwise specified. It should also be understood that the various terms used herein are for describing particular embodiments only and are not intended to be limiting.

[0043] In several embodiments of the present invention, this application discloses polypropylene blends comprising a propylene-based elastomer and a propylene copolymer, wherein the propylene-based elastomer comprises at least 60 wt% propylene-derived units and 1 to 35 wt% of at least one selected from ethylene and C4-C 20 The unit is derived from the comonomer of an α-olefin, based on the total weight of the propylene-based elastomer, wherein the heat of melt of the propylene-based elastomer is less than 80 J / g, the melting point of the propylene-based elastomer is less than or equal to 105°C, and wherein the propylene copolymer is propylene and at least one selected from ethylene and C4-C 20 Copolymers of α-olefin comonomers, with a weight-average molecular weight ranging from greater than 8000 g / mol, or greater than 10000 g / mol, or greater than 12000 g / mol, or greater than 20000 g / mol to less than 1,000,000 g / mol, or less than 800,000 g / mol.

[0044] According to the polypropylene blend of the present invention, the content of propylene-derived units in the propylene-based elastomer is from a lower limit of 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 84 wt%, 85 wt% to an upper limit of 85 wt%, 90 wt%, 92 wt%, 94 wt%, 95 wt%.

[0045] According to the polypropylene blend of the present invention, at least one of the propylene-based elastomers is selected from ethylene and C4-C. 20 The content of the comonomer-derived units of the α-olefin is 5-35 wt%, or 7-30 wt%, or 8-25 wt%, or 8-20 wt%, or 8-18 wt%.

[0046] According to the polypropylene blend of the present invention, the crystallinity of the propylene-based elastomer is 2% to 65% of the crystallinity of isotactic polypropylene.

[0047] According to the polypropylene blend of the present invention, the graded melt flow rate (MFR) of the propylene-based elastomer is 2-20 g / 10 min.

[0048] According to the polypropylene blend of the present invention, at least one of the propylene-based elastomers is selected from ethylene and C4-C. 20 The comonomer of the α-olefin is selected from ethylene, 1-hexene or 1-octene, with ethylene being preferred.

[0049] According to the polypropylene blends of the present invention, the heat of melt of the propylene-based elastomer is from a lower limit of 1.0 J / g, 1.5 J / g, 3.0 J / g, 4.0 J / g, 6.0 J / g to an upper limit of 35 J / g, 40 J / g, 50 J / g, 60 J / g, 70 J / g, 75 J / g, 80 J / g.

[0050] According to the polypropylene blend of the present invention, the propylene-based elastomer may further comprise diene-derived units.

[0051] According to the polypropylene blend of the present invention, the diene is selected from 1,4-hexadiene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,7-cyclododecadiene, tetrahydroindene, norbornene, methyl-tetrahydroindene, cyclopentadiene, bicyclo-(2.2.1)-hept-2,5-diene, alkenyl norbornene, ethylenediene, etc. 5-Methylene-norbornene, 5-ethide-2-norbornene, 5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexide-2-norbornene, 5-vinyl-2-norbornene, vinylcyclohexene, allylcyclohexene, vinylcyclooctene, 4-vinylcyclohexene, allylcyclodecene, vinylcyclododecene.

[0052] According to the polypropylene blends of the present invention, the content of the propylene-based elastomeric diene-derived units ranges from a lower limit of 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.5 wt%, 1 wt%, 3 wt%, 5 wt% to an upper limit of 1.5 wt%, 2.5 wt%, 3 wt%, 4.5 wt%, 5 wt%, 7 wt%, 10 wt%, 15 wt%.

[0053] According to the polypropylene blend of the present invention, the content of the propylene-based elastomer is 6 wt% to 30 wt%, 10 wt% to 30 wt%, or 10 wt% to 25 wt%, based on the total weight of the polypropylene blend.

[0054] According to the polypropylene blend of the present invention, the content of the propylene copolymer is 70 wt% to 94 wt%, 70 wt% to 90 wt%, or 75 wt% to 90 wt%, based on the total weight of the polypropylene blend.

[0055] According to the polypropylene blend of the present invention, the molecular weight distribution (Mw / Mn) of the propylene copolymer is 1.5 to 10, preferably 1.6 to 7, more preferably 1.7 to 5 and most preferably 1.8 to 4.

[0056] According to the polypropylene blend of the present invention, the 1% secant flexural modulus of the propylene copolymer is 100 MPa to 2300 MPa, preferably 200 MPa to 2100 MPa, more preferably 300 MPa to 2000 MPa and most preferably 400 MPa to 1800 MPa.

[0057] According to the polypropylene blend of the present invention, the melt flow rate (MFR) of the propylene copolymer is from 0.1 dg / min to 2500 dg / min, preferably from 0.3 dg / min to 500 dg / min.

[0058] Propylene-based elastomers

[0059] The propylene-based elastomer may be a propylene-derived unit with C2 and C3. 4-10 A copolymer of α-olefin-derived units having: (a) C2 and / or C 4-10 The α-olefin-derived unit content ranges from about 5-30 wt%, preferably about 5-25 wt%, more preferably about 8-25 wt%, and even more preferably 8-15 wt%; (b) the ICD is greater than or equal to 75%, greater than 80%, greater than 85%, preferably greater than 90%; (c) the Tm ranges from about 25°C to about 110°C, preferably about 25°C to about 85°C, 25°C to about 75°C, about 25°C to about 65°C, and about 3... 0°C to about 75°C, more preferably about 30°C to about 60°C; (d) Hf ranges from about 0.5 to about 70 J / g, preferably about 0.5 to about 50 J / g, or more preferably about 5 to about 40 J / g; (e) Mw / Mn ranges from about 1.2 to about 4.5; and (f) MFR ranges from about 0.1 to about 40 g / 10 min, preferably about 1 to about 20 g / 10 min, more preferably about 2 to about 5 g / 10 min.

[0060] Propylene-derived units and one or more C2 and C3 compounds4-10 In copolymers of α-olefin-derived units, C2 and / or C 4-10 The content of α-olefin-derived units ranges from about 5-30 wt%, preferably about 5-25 wt%, more preferably about 8-25 wt%, and even more preferably 8-15 wt%, based on the weight of the copolymer. The balance of the propylene copolymer may be one or more of the C2 and C3 groups specified above. 4-10 α-olefin-derived units. Therefore, propylene-derived units that can be used in this invention are with one or more C2 and C3 groups. 4-10 The average propylene content in the copolymer of α-olefin-derived units is about 70 to about 95 wt%, more preferably about 75 to about 95 wt%, even more preferably about 75 to about 92 wt%, and most preferably about 85 to about 92 wt%, based on the weight of the copolymer.

[0061] Propylene-derived units with one or more C2 and C3 groups 4-10In copolymers of α-olefin-derived units, the intermolecular density (ICD) is greater than 75%, greater than 80%, greater than 85%, and preferably greater than 90%. ICD is an indicator of intermolecular uniformity. The intermolecular composition distribution of the copolymer is determined by thermal fractionation in a solvent. Typical solvents are saturated hydrocarbons, such as hexane or heptane. The thermal fractionation process is as follows: The ICD can be determined by the weight of polymer separated in one or two adjacent soluble fractions, and the remaining polymer in immediately or continuously fractions; and in each of these fractions, the difference in the weight % content of copolymer monomers is not greater than 20 wt% (relative) of the average weight % of copolymer monomers in the copolymer, preferably 10 wt% (relative). Each fraction is obtained by increasing the temperature by about 8°C between fractions. The ICD of the copolymer was determined by thermal fractionation in hexane as described below: Approximately 30 g of the semi-amorphous polymer was cut into small cubic pieces of approximately 1 / 8 inch (0.32 cm) on the side and introduced together with 50 mg of Irganox 1076 (an antioxidant commercially available from Ciba Specialty Chemicals (Basel, Switzerland)) into a screw-capped, thick-walled glass vial. Then, 425 ml of hexane (the main mixture of the n- and iso-isomers) was added to the contents of the vial, and the sealed vial was maintained at approximately 23°C for 24 hours. At the end of this period, the solution was gently poured out, and the residue was treated with additional hexane at 23°C for an additional 24 hours. At the end of this period, the two hexane solutions were combined and evaporated to obtain a polymer residue soluble at 23°C. Sufficient hexane was added to the residue to bring the volume to 425 ml, and the bottle was maintained at approximately 31°C for 24 hours in a covered circulating water bath. The soluble polymer was gently poured out, and an additional amount of hexane was added at approximately 31°C for another 24 hours before gently pouring out. In this manner, soluble semi-amorphous polymer fractions at 40°C, 48°C, 55°C, and 62°C were obtained by increasing the temperature by approximately 8°C between the fractions. The soluble polymer was dried, weighed, and its composition was analyzed in the form of wt% ethylene content. For the production of copolymers with the desired narrow intermolecular compositional distribution, it is advantageous if (1) a metallocene catalyst is used, preferably a metallocene catalyst that behaves as if only the first and second monomer sequences were added, and (2) the copolymer is thoroughly mixed in a continuously flowing stirred tank polymerization reactor, which provides a single polymerization environment for substantially all polymer chains in the copolymer.

[0062] Propylene-derived units and one or more C2 and C4-C 10The Tm range of the copolymer of α-olefin-derived units is about 25°C to about 110°C, preferably about 25°C to about 85°C, 25°C to about 75°C, about 25°C to about 65°C, about 30°C to about 75°C, and more preferably about 30°C to about 60°C. Tm is measured using the DSC process described above.

[0063] Propylene-derived units and one or more C2 and C4-C 10 H of copolymers of α-olefin-derived units f The concentration ranges from about 0.5 to about 70 J / g, preferably from about 0.5 to about 50 J / g, or more preferably from about 5 to about 40 J / g. Preferably, the propylene-derived unit and one or more C2 and C4-C atoms... 10 The copolymer of α-olefin-derived units also has a heat of fusion Hf greater than or equal to about 1 J / g, preferably greater than or equal to about 2.5 J / g, and more preferably greater than or equal to about 5 J / g. As described above, Hf is determined using a differential scanning calorimeter (DSC) according to the procedure described in ASTM E794-06. The heat of fusion (Hf once melted, or heat of crystallization Hc once crystallized) is determined using the area under the DSC curve; if the Hf value from melting differs from the Hf value obtained for the heat of crystallization, the value from melting (Tm) should be used.

[0064] Propylene-derived units and one or more C2 and C4-C 10 The Mw / Mn ratio of copolymers of α-olefin-derived units ranges from about 1.2 to about 4.5. Techniques for determining molecular weight (Mn, number-average molecular weight, and Mw, weight-average molecular weight) and molecular weight distribution (Mn / Mw) can be found in U.S. Patent No. 4,540,753 (incorporated herein by reference) and Macromolecules 1988, 21,3360 (also incorporated herein by reference). Mw and Mn can be determined by size exclusion chromatography (SEC), for example, 3D SEC, also known as GPC-3D. Mn / Mw, also known as the polydispersity index, is the ratio of Mw to Mn.

[0065] Propylene-derived units and one or more C2 and C4-C 10 The MFR of copolymers of α-olefin-derived units ranges from about 0.1 to about 40 g / 10 min, preferably from about 1 to about 20 g / 10 min, and more preferably from about 2 to about 5 g / 10 min. Similarly, the MFR is measured at 230°C and 2.16 kg using ASTM D-1238.

[0066] In a preferred embodiment, the propylene-derived unit and one or more C2 and C4-C atoms... 10The copolymer of α-olefin-derived units has a g' greater than or equal to about 0.99. As previously stated, g' is determined. Similarly, it is well known in the art that as the g' value decreases, long-chain branching increases.

[0067] Propylene-derived units and one or more C2 and C4-C 10 Copolymers of α-olefin-derived units can be characterized by other properties as described below, such as Tc, density, crystallinity %, and essentially the absence of regio-errors corresponding to approximately 14.6 and 15.7 ppm. 13 C NMR peak (the intensity of the peak is approximately the same), mm three-unit stereoregularity index, propylene stereoregularity index m / r, and Mooney viscosity.

[0068] In a particular embodiment, the propylene-derived unit and one or more C2 and C4-C 10 The copolymer of α-olefin-derived units may have any one of the following: (i) a Tc less than or equal to about 200°C, more preferably less than or equal to 150°C; (ii) a density in the range of about 0.85 to about 0.92 g / cm³. 3 More preferably, approximately 0.87-0.90 g / cm³ 3 More preferably, about 0.88-about 0.89 g / cm³ 3 (iii) Crystallinity % ranges from 0.25% to 40%, preferably from about 0.25% to about 25%, more preferably from about 0.5% to about 22%, and most preferably from about 0.5% to about 20%; (iv) The ternary unit stereoregularity index is greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 82%, greater than or equal to 85%, or greater than or equal to 90%; (v) There are substantially no regions of error corresponding to about 14.6 and about 15.7 ppm. 13 C NMR peaks with approximately equal intensities; (vi) m / r greater than 1; and (vii) Mooney viscosity less than 100, more preferably less than 75, even more preferably less than 60, and most preferably less than 30.

[0069] Propylene-derived units and one or more C2 and C4-C 10 The temperature coefficient (Tc) of copolymers of α-olefin-derived units can be less than or equal to about 200°C, more preferably less than or equal to 150°C. Tc is measured using the DSC method discussed above.

[0070] At room temperature, propylene-derived units and one or more C2 and C4-C 10 The density range of copolymers of α-olefin-derived units can be about 0.85 to about 0.92 g / cm³. 3 More preferably, about 0.87-0.90 g / cm³3 More preferably, about 0.88-about 0.89 g / cm³ 3 This is measured using the ASTM D-1505 test method.

[0071] Propylene-derived units and one or more C2 and C4-C 10 The crystallinity % of the copolymer of α-olefin-derived units can range from 0.25% to 40%, preferably from about 0.25% to about 25%, more preferably from about 0.5% to about 22%, and most preferably from about 0.5% to about 20%, wherein the crystallinity % is determined using the DSC method described above. The heat of transition (Hf once melting, or Hc once crystallizing; if the Hf value from melting differs from the Hf value obtained for the heat of crystallization, the value from melting (Tm) should be used) is determined using the area under the DSC curve. Crystallinity (also known as % crystallinity) can be calculated using the heat of transition. % crystallinity (X%) is calculated using the following formula: [Area under the curve (in J / g) / H° (in J / g)] * 100, where H° is the heat of fusion of the homopolymer of the major monomer component. These values ​​for H° were obtained from John Wiley and Sons' Polymer Handbook, 4th edition, New York, 1999, with the exceptions of 290 J / g used as the equilibrium heat of fusion (H°) for 100% crystalline polyethylene, 140 J / g used as the equilibrium heat of fusion (H°) for 100% crystalline polybutene, and 207 J / g (H°) used as the heat of fusion for 100% crystalline polypropylene.

[0072] Propylene-derived units and one or more C2 and C4-C 10 The copolymers of α-olefin-derived units essentially lack regions corresponding to approximately 14.6 and 15.7 ppm – incorrect. 13 The C NMR peaks are approximately equal in intensity, corresponding to regions of approximately 14.6 and 15.7 ppm – this is incorrect. 13 The C10 NMR peaks are considered to be the result of stereoselective 2,1-misintercalation of propylene units into the grown polymer chain. In typical propylene-ethylene copolymers produced via shape-limited non-metallocene catalysts, these peaks have approximately equal intensity and represent about 0.02–7 mol% propylene intercalation into the homopolymer or copolymer chain. The propylene-derived units are associated with one or more C2 and C4-C6 groups. 10 The copolymers of α-olefin-derived units do not have regions corresponding to approximately 14.6 and approximately 15.7 ppm - incorrect. 13 The C NMR peaks were obtained using a metallocene catalyst.

[0073] Propylene-derived units and one or more C2 and C4-C 10 The copolymer of α-olefin-derived units also has a content of 75% or more, 80% or more, 82% or more, 85% or more, or 90% or more as described above. 13 The mm ternary stereoregularity index of three propylene units was measured using C10 NMR technology. 13 C-NMR spectroscopy was used to determine the microstructure of the polymer discussed here, including the concentrations of isotactic and syndiotactic binary units ([m] and [r]), tripartite units ([mm] and [rr]), and pentatomic units ([mmmm] and [rrrr]). The sample was dissolved in d2-1,1,2,2-tetrachloroethane. Spectra were recorded at 125 °C using a 100 MHz NMR spectrometer. The resonance peak of the polymer was noted as [mmmm] = 21.8 ppm. The calculations involved in the NMR characterization of the polymer followed the work of F.A. Bovey in "Polymer Conformation and Configuration," Academic Press, New York, 1969, and J. Randall in "Polymer Sequence Determination, 13C-NMR Method," Academic Press, New York, 1977. The percentage of methylene sequences of length 2 is calculated as follows, %(CH2)2: the integral of methyl carbon in the range of 14-18 ppm (which corresponds to the concentration of methylene sequences of length 2) divided by the sum of the integrals of methylene sequences of length 1 in the range of 45-49 ppm and the integrals of methyl carbon in the range of 14-18 ppm, multiplied by 100. This is the minimum calculated value for the amount of methylene contained in two or more sequences, because methylene sequences greater than 2 are excluded. These assignments are based on HNCheng and JAEwen, Makromol. Chem. 1989, 190, 1931. The m-triatriate stereoregularity index of a polymer is the relative stereoregularity of three adjacent propylene unit sequences (a chain composed of head-tail bonds), expressed as a binary combination of m and r sequences. For the copolymers of the present invention, it is generally expressed as the ratio of the number of units with the specified stereoregularity to all propylene triunits within the copolymer. This can be determined according to the propylene copolymer's... 13 CNMR spectroscopy and the following formula were used to determine the stereoregularity index (mm fraction) of the propylene copolymer's three-unit assembly:

[0074]

[0075] Where PPP(mm), PPP(mr), and PPP(rr) represent the peak areas obtained from the methyl group in the second unit within the following three propylene unit chains (which consist of head and tail bonds):

[0076]

[0077] As described in U.S. Patent Nos. 5,504,172 and 6,642,316 (column 6, lines 38 through 9, line 18), the propylene copolymer is measured. 13 C10 NMR spectra. The spectra involving the methyl carbon region (19-23 parts per million (ppm)) can be divided into three regions: a first region (21.2-21.9 ppm), a second region (20.3-21.0 ppm), and a third region (19.5-20.3 ppm). Referencing articles in *Polymer*, Vol. 30 (1989), p. 1350, or *Macromolecules*, 17 (1984), 1950, each peak within this spectrum was determined (in case of conflict between the *Polymer* and *Macromolecules* articles, the *Polymer* article should be considered dominant). In the first region, the methyl group in the second unit resonates within the three propylene-derived unit chains expressed in PPP (mm). In the second region, among the three propylene-derived unit chains represented by PPP(mr), the methyl group in the second unit resonates, and in the propylene-derived unit where its adjacent units are propylene-derived and ethylene-derived units, the methyl group (PPE-methyl) resonates (around 20.7 ppm). In the third region, among the three propylene-derived unit chains represented by PPP(rr), the methyl group in the second unit resonates, and in the propylene-derived unit where its adjacent unit is an ethylene unit, the methyl group (EPE-methyl) resonates (around 19.8 ppm). The calculation of the stereoregularity index of the mm ternary set is outlined in the technique shown in U.S. Patent No. 5,504,172. The peak areas of erroneously inserted propylene (both 2,1 and 1,3) can be obtained from the total peak area of ​​the second and third regions (based on the peak areas of the three propylene unit chains (PPP(mr) and PPP(rr)) consisting of head and tail bonds). Therefore, the peak areas of PPP(mm), PPP(mr), and PPP(rr) can be evaluated, and the stereoregularity index of the mm ternary unit group composed of head-tail bonds can be determined. JAEwen, "Catalytic Polymerization of Olefins", (Ewen Method), Eds.T.Keii, K.Soga, Kodanska Elsevier Pub., Tokyo, 1986, p. 271, describes how this can be determined based on the polymer's...13 Further information on the stereoregularity of the mm ternary unit group determined by C-NMR spectroscopy, and as described in detail in paragraphs

[0046] -

[0054] on page 8 of U.S. Patent No. 6,884,850, all of which are incorporated herein by reference.

[0078] Propylene-derived units and one or more C2 and C4-C 10 The propylene stereoregularity index of copolymers of α-olefin-derived units, expressed as the ratio of m to r (m / r), can be greater than 1. Based on the above... 13 The stereoregularity index m / r of propylene was determined using 1 / 2 C NMR. As discussed in HNCheng, Macromolecules, 17, 1950 (1984), the stereoregularity index m / r of propylene was calculated. The designation "m" or "r" describes the stereochemistry of the paired, continuous propylene groups, where "m" indicates meso and "r" indicates racemic. An m / r ratio of 0 to less than 1.0 generally describes syndiotactic polymers, and an m / r ratio of 1.0 describes atactic materials, while a ratio greater than 1.0 describes isotactic materials. Isotactic materials can theoretically have near-infinite ratios, and many byproduct atactic polymers have sufficient isotactic content, resulting in ratios greater than 50. Propylene-derived units are associated with one or more C2 and C4-C groups. 10 Copolymers of α-olefin-derived units can have isotactic stereoregular propylene crystallinity. The term “stereoregular” as used herein refers to a majority, i.e., more than 80% of the propylene-derived units in the polypropylene (excluding any other monomers, such as ethylene) having the same stereochemical orientation of 1,2-intercalated and side-mounted methyl groups, either meso or racemic.

[0079] Propylene-derived units and one or more C2 and C4-C compounds as determined according to ASTM D1646. 10 The Mooney viscosity ML(1+4)@125°C of the copolymer of α-olefin-derived units can be less than 100, more preferably less than 75, even more preferably less than 60, and most preferably less than 30.

[0080] In the embodiments described herein, a metallocene catalyst is used to produce propylene-derived units and one or more C2 and C4-C atoms. 10 Copolymers of α-olefin-derived units. U.S. Patent No. 6,500,563 describes in detail, in the form of "Second Polymer Component (SPC)," the propylene-derived units used in this invention and one or more C2 and C4-C copolymers. 10Copolymers of α-olefin-derived units, the entirety of which are incorporated herein by reference. Propylene-derived units and one or more C2 and C4-C... 10 Copolymers of α-olefin-derived units may include copolymers prepared according to the processes described in WO 02 / 36651; U.S. Patent No. 6,992,158, and / or WO 00 / 01745. Preferred methods for producing copolymers are found in U.S. Patent No. 6,881,800. Preferred copolymers are marketed under the trade name Vistamaxx. TM Commercial purchase (ExxonMobil, Baytown TX). Suitable examples include: Vistamaxx. TM 6202, Vistamaxx TM 3980FL, Vistamaxx TM 3020FL, Vistamaxx TM 6102, and Vistamaxx TM 3000.

[0081] propylene copolymer

[0082] The propylene copolymer may be a semi-crystalline polymer, each semi-crystalline polymer comprising propylene and 0-5 wt%, preferably 0.1-4 wt%, preferably 0.25-3 wt% of an α-olefin comonomer (based on the weight of the polymer). Preferably, the α-olefin comonomer is C2-C 10 α-olefins are preferably selected from ethylene, butene, pentene, hexene, hepten, octene, nonene, and decene, with ethylene, butene, hexene, and octene being more preferred, and ethylene being even more preferred. (For the purposes of this invention, when the copolymer is described as comprising propylene and one or more C2-C10 olefins or α-olefins, the C2-C10 olefin or α-olefin does not include C3, such as propylene.)

[0083] The preferred semi-crystalline polymer has a melting point of 100-170°C, preferably 110-170°C, and more preferably 125-170°C (Tm - secondary melt, as determined by DSC as described above).

[0084] The preferred semi-crystalline polymer has a melt flow rate of 0.1-200 dg / min, preferably 0.25-100 dg / min, preferably 0.5-50 dg / min, preferably 0.5-20 dg / min, preferably 1-20 dg / min (ASTM 1238-D, 2.16 kg, 230 °C).

[0085] The preferred semi-crystalline polymer has an elongation at break of 700% or less, preferably 300-700%, as determined by ASTM D638 (2 in / min / 50 mm / min, 0.125 inch (3.18 mm) thick injection molded sample).

[0086] Preferred semi-crystalline polymers have a 1° secant flexural modulus of 100,000 psi to 250,000 psi (690-1720 MPa), preferably 150,000 psi to 250,000 psi (1035-1720 MPa), determined by ASTM D-790A (0.05 in / min / 1.3 mm / min). "Highly crystalline polypropylene," such as those with values ​​above 250,000 psi (1720 MPa), can also be used.

[0087] In practices of this invention, any propylene polymer having 0-5 wt% comonomer, a melting point of 100-170°C, and an MFR of 200 dg / min or lower can be used. Suitable examples include polymers produced using Ziegler-Natta catalyst systems, metallocene systems, etc. The polymers can be prepared by any method, including solution, slurry, gas-phase, supercritical, or high-pressure methods. In a particularly preferred embodiment, the propylene polymers used herein have a molecular weight distribution (Mw / Mn) of 5 or lower, preferably 1.5-4, preferably 1.5-3. In another preferred embodiment, preferred propylene polymers used herein include those produced using metallocene catalyst systems. In yet another embodiment, preferred propylene polymers used herein include those having a composition distribution width index (CDBI) of 60% or higher, preferably 70% or higher, preferably 80% or higher, preferably 90% or higher. (CDBI is determined as described in WO 93 / 03093, with the change that any fraction with a weight-average molecular weight (Mw) below 25,000 g / mol is ignored.) Preferred propylene polymers that can be used in the practice of this invention include those using ACHIEVE. TM These are propylene polymers sold under the trade name of ExxonMobil Chemical Company. Particularly useful grades include ACHIEVE, purchased from ExxonMobil Chemical Company in Houston, Texas. TM 3854, ACHIEVE TM 1654E1, ACHIEVE TM 3825, ACHIEVE TM1605. Other preferred propylene polymers that can be used to carry out the invention include those propylene homopolymers and random copolymers available from ExxonMobil Chemical Company under the following grades: PP1024E4, PP1042, PP1032, PP1044, PP1052, PP1105E1, PP3155 and PP9852E1, PP9272, PP9513, PP9544, PP9562. In some cases, impact copolymers can be used to carry out the invention. Several are available from ExxonMobil Chemical Company (e.g., PP7032E2).

[0088] The propylene copolymer described in this invention can also be a high-melting-point propylene polymer. For the purposes of this invention, a high-melting-point propylene polymer (HMPP) is defined as a propylene polymer having a peak melting point greater than 100°C (preferably greater than 110°C, more preferably greater than 120°C, more preferably greater than 130°C, more preferably greater than 140°C, more preferably greater than 150°C) and preferably having a melt flow rate of 0.1-2000 dg / min (preferably 100 dg / min or lower). Preferably, the HMPP has a crystallinity of greater than 35%, preferably greater than 40%, more preferably greater than 45%, and more preferably greater than 50%.

[0089] In a preferred embodiment, the blends of the present invention comprise one or more HMPPs, each HMPP comprising propylene and preferably 0-5 wt% of an α-olefin comonomer (based on the weight of the polymer), preferably 0.1-4 wt%, more preferably 0.25-3 wt%. Preferably, the α-olefin comonomer is C2-C 10 α-olefins, preferably selected from ethylene, butene, pentene, hexene, hepten, octene, nonene, and decene, with ethylene, butene, hexene, and octene being the most preferred, and ethylene being the most preferred. (For the purposes of this invention, when a copolymer is referred to as comprising propylene and one or more C2-C...) 10 When it is an olefin or α-olefin, the C2-C 10 Alkenes or α-olefins excluding C3, such as propylene).

[0090] HMPP preferably has a melting point of 105-170°C, more preferably 110-170°C, and more preferably 125-170°C (Tm - secondary melting as measured by DSC as described above).

[0091] The preferred HMPP has a melt flow rate of 0.1-200 dg / min, preferably 0.25-100 dg / min, preferably 0.5-50 dg / min, preferably 0.5-20 dg / min, preferably 1-20 dg / min (ASTM 1238-D, 2.16 kg, 230 °C).

[0092] The preferred HMPP has an elongation at break of 700% or less, preferably 300-700% (measured by ASTM D 638, 2in / min / 50mm / min for a 0.125in (3.18mm) thick injection molded sample).

[0093] The preferred HMPP has a 1° secant flexural modulus of 100,000 psi-250,000 (690-1720 MPa), preferably 150,000 psi-250,000 psi (1035-1720 MPa), as measured by ASTM D-790A (0.05 in / min / 1.3 mm / min).

[0094] "Highly crystalline polypropylene", such as those with a value greater than 250,000 psi (1720 MPa), can also be used as HMPP in this invention.

[0095] Any propylene polymer having 0-5 wt% comonomer, a melting point of 100-170°C, and an MFR of 200 dg / min or lower can be used as an HMPP in the practice of this invention. Suitable examples include polymers prepared from Ziegler-Natta catalyst systems, metallocene systems, etc. The polymers can be prepared by any means, including solution, slurry, gas phase, supercritical, or high pressure. In a particularly preferred embodiment, the HMPP available herein has a molecular weight distribution (Mw / Mn) of 5 or lower, preferably 1.5-4, preferably 1.5-3. In another preferred embodiment, the preferred HMPPs available herein include those prepared by metallocene catalyst systems. In yet another embodiment, the preferred HMPPs available herein include those with a composition distribution width index (CDBI) of 60% or higher, preferably 70% or higher, preferably 80% or higher, preferably 90% or higher. (The CDBI measurement, as described in WO 93 / 03093, is modified by disregarding any fraction with a weight-average molecular weight (Mw) less than 25,000 g / mol). Preferred HMPPs usable in the practice of this invention include those produced by ExxonMobil Chemical Company under the trade name ACHIEVE. TM Those propylene polymers for sale. Particularly useful grades include ACHIEVE, available from ExxonMobil Chemical Company in Houston, Texas. TM 3854, ACHIEVE TM 1654E1, ACHIEVE TM 3825, ACHIEVE TM1605. Other preferred HMPPs that can be used in the practice of this invention include those propylene homopolymers, as well as random copolymers (which are available from ExxonMobil Chemical Company under the following grade names): PP1024E4, PP1042, PP1032, PP1044, PP1052, PP1105E1, PP3155 and PP9852E1, PP9272, PP9513, PP9544, PP9562.

[0096] The propylene copolymer described in this invention can also be a thermoplastic polymer, which is a propylene copolymer (random or block copolymer) of propylene-derived units and units selected from ethylene and C4-C. 20 In another embodiment, the α-olefin-derived unit is typically selected from ethylene and C4-C. 10 α-olefin-derived units. Ethylene or C4-C 10 The presence of α-olefin-derived units in the copolymer is, in one embodiment, 0.1 wt% to 50 wt%, in another embodiment, 0.5 to 30 wt%, in yet another embodiment, 1 to 15 wt%, and in yet another embodiment, 0.1 to 5 wt%, wherein the desired copolymer comprises ethylene and C4-C in any combination of any upper and lower wt% limits described herein. 20 α-olefin-derived units. The propylene copolymer will have a weight-average molecular weight of greater than 8,000 g / mol in one embodiment, greater than 10,000 g / mol in another embodiment, greater than 12,000 g / mol in yet another embodiment, greater than 20,000 g / mol in yet another embodiment, less than 1,000,000 g / mol in yet another embodiment, and less than 800,000 in yet another embodiment, wherein the desired copolymer may include any upper and lower molecular weight limits described herein.

[0097] The propylene copolymers useful and particularly desirable in this article have a molecular weight distribution (Mw / Mn) of 1.5-10, 1.6-7 in another embodiment, 1.7-5 in yet another embodiment, and 1.8-4 in yet another embodiment. The Gardner impact strength of this propylene copolymer (tested at 23°C on a 0.125-inch (approximately 0.32 cm) disk) can be 20 in-lb to 1000 in-lb (approximately 0.14 to approximately 6.8 MPa) in one embodiment, 30 in-lb to 500 in-lb (approximately 0.21 to approximately 3.45 MPa) in another embodiment, and 40 in-lb to 400 in-lb (approximately 0.28 to approximately 2.76 MPa) in yet another embodiment. In yet another embodiment, the 1% secant flexural modulus of the propylene copolymer is 100 MPa-2300 MPa, in another embodiment it is 200 MPa-2100 MPa, and in yet another embodiment it is 300 MPa-2000 MPa, wherein the desired polyolefin can exhibit any combination of any upper and lower flexural modulus limits. The melt flow rate (MFR) of the propylene copolymer is 0.1 dg / min-2500 dg / min in one embodiment and 0.3-500 dg / min in another embodiment.

[0098] In another embodiment, the thermoplastic polymer may be a propylene copolymer comprising propylene and one or more other monomers selected from ethylene and C4-C4 monomers. 20 Linear, branched, or cyclic monomers, in some embodiments, selected from C4-C 12 Linear or branched α-olefins, preferably butene, pentene, hexene, hepten, octene, nonene, decene, dodecene, 4-methyl-pentene-1, 3-methyl-pentene-1, 3,5,5-trimethyl-hexene-1, etc. This monomer may be present in up to 50 wt%, preferably 0-40 wt%, more preferably 0.5-30 wt%, more preferably 2-30 wt%, and even more preferably 5-20 wt%.

[0099] In a preferred embodiment, any propylene polymer containing 0.01-5 wt% comonomer, preferably with a melting point of 100-170 °C and an MFR of 200 dg / min or less, can be used as a thermoplastic polymer in the practice of this invention. Suitable examples include polymers prepared by Ziegler-Natta catalyst systems, metallocene systems, etc. The polymer can be prepared by any means, including solution, slurry, gas phase, supercritical, or high pressure. In a particularly preferred embodiment, the propylene polymers available herein have a molecular weight distribution (Mw / Mn) of 5 or less, preferably 1.5-4, preferably 1.5-3. In another preferred embodiment, preferred propylene polymers available herein as thermoplastic polymers include those prepared by metallocene catalyst systems. In another embodiment, preferred propylene polymers available herein include those with a composition distribution width index (CDBI) of 60% or higher, preferably 70% or higher, preferably 80% or higher, preferably 90% or higher. (CDBI measurements as described in WO 93 / 03093, with the modification of ignoring any fractions with a weight-average molecular weight (Mw) less than 25,000 g / mol). Preferred propylene polymers that can be used as thermoplastic polymers in the practice of this invention include those marketed by ExxonMobil Chemical Company under the trade name ACHIEVE. TM Those propylene polymers for sale. Particularly useful grades include ACHIEVE, available from ExxonMobil Chemical Company in Houston, Texas. TM 3854, ACHIEVE TM 1654E1, ACHIEVE TM 3825, ACHIEVE TM 1605. Other preferred propylene polymers that can be used as thermoplastic polymers in the practice of this invention include those propylene homopolymers and random copolymers available from ExxonMobil Chemical Company under the following grade names: PP1024E4, PP1042, PP1032, PP1044, PP1052, PP1105E1, PP3155 and PP9852E1, PP9272, PP9513, PP9544, PP9562.

[0100] blends

[0101] The polypropylene blends of the present invention can be in the form of single-layer or multi-layer films, with a relatively reduced thickness, typically 50 to 150 μm, preferably 80 to 120 μm, and can be prepared using a simple compounding process. Even with such a reduced thickness, the polypropylene blends of the present invention exhibit excellent properties, particularly as follows:

[0102] (i) 1% secant modulus of 300 to 600 MPa, preferably 320 to 550 MPa in the longitudinal direction (MD) and 350 to 600 MPa, preferably 380 to 550 MPa in the transverse direction (TD).

[0103] (ii) a tensile strength of 30 to 40 MPa, preferably 32 to 38 MPa, in the longitudinal direction (MD) and 25 to 35 MPa, preferably 28 to 32 MPa, in the transverse direction (TD).

[0104] (iii) an elongation at break of 540% to 640%, preferably 580% to 620%, in the longitudinal direction (MD) and 600% to 640%, preferably 610% to 620%, in the transverse direction (TD).

[0105] (iv) Elmandorf tear with a longitudinal (MD) length of 1 to 4 g / μm, preferably 1.5 to 3 g / μm, and a transverse (TD) length of 3 to 11 g / μm, preferably 5 to 10 g / μm.

[0106] (v) Haze of 84.8% to 85.4%, gloss of 1 to 2.5 (45°, GU).

[0107] The polypropylene blends of the present invention have any one, any two, any three, any four, or all five of the above properties (i) to (ii), preferably all five.

[0108] As used herein, “blend” can refer to a dry or extrusion blend of two or more different polymers, and an in-reactor blend, including blends produced in a single reactor zone using multiple or mixed catalyst systems, and blends produced in one or more reactors under the same or different conditions using one or more catalysts (e.g., blends produced in tandem reactors (same or different), where each reactor operates under different conditions and / or with different catalysts). The blend may also contain at least one additive component (C) to (M): (C) a lubricant; (D) a polymer processing aid; (E) an antioxidant; (F) a metal passivator; (G) a UV-promoted degradation inhibitor as a UV stabilizer; (H) a slip agent; (I) a hindered amine stabilizer; (J) an anti-caking agent; (K) a colorant; (L) an antifogging agent; and (M) an antistatic agent; provided that the total amount of the at least one additive is >0 to 5 wt% of the polyolefin composition.

[0109] Additional test methods include the following.

[0110]

[0111] Example

[0112] It should be understood that although the invention has been described in conjunction with specific embodiments thereof, the foregoing description is intended to be illustrative and not to limit the scope of the invention. Other aspects, advantages, and improvements will be apparent to those skilled in the art to which this invention pertains.

[0113] Therefore, the following embodiments are provided to offer a complete disclosure and description to those skilled in the art and are not intended to limit the scope of the inventors' view of their invention. Unless otherwise stated, the amounts of components in this invention are by weight.

[0114] Components used in the examples:

[0115] Propylene-based elastomer: Vistamaxx 3980FL (abbreviated as VM3980FL), from ExxonMobil.

[0116] Propylene copolymer: PP9513, from ExxonMobil.

[0117] Example 1

[0118] 90% PP9513 was blended with 10% VM3980FL to obtain blends, and the tensile strength, flexibility, elongation, tear strength and optical properties of the obtained blends were measured accordingly.

[0119] Example 2

[0120] 80% PP9513 was blended with 20% VM3980FL to obtain blends, and the tensile strength, flexibility, elongation, tear strength and optical properties of the obtained blends were measured accordingly.

[0121] Example 3

[0122] 75% PP9513 was blended with 25% VM3980FL to obtain blends, and the tensile strength, flexibility, elongation, tear strength and optical properties of the obtained blends were measured accordingly.

[0123] Results and discussion

[0124] 1. Tensile strength

[0125] For cutting strips, a backing film with higher tensile strength is preferred, as it is less likely to be damaged during the cutting process. For example... Figure 1As shown, increasing the amount of Vistamaxxx 3980FL significantly increases the tensile strength in the MD direction. An 11%–39% increase in tensile strength was achieved compared to imported high-end commercial samples, even with greater film thicknesses. Optimal performance was achieved at approximately 20% Vistamaxxx 3980FL loading.

[0126] 2. Flexibility

[0127] For the cutting strip, higher flexibility is preferred to achieve good adhesion to the substrate and good conformability during grinding and cutting processes. To investigate the flexibility of films based on different Vistamaxx 3980FL formulations, the 1% secant modulus of the three formulations was measured. Figure 2 As shown, increasing the amount of Vistamaxx 3980FL by 10%-25% resulted in a 1% decrease in secant modulus in both the MD and TD directions, demonstrating the value of Vistamaxx 3980FL in improving membrane flexibility. Optimal performance was achieved at approximately 25% Vistamaxx 3980FL loading, resulting in lower modulus and higher flexibility compared to imported high-end commercial samples.

[0128] 3. Elongation

[0129] Polyolefin-backed sheets exhibit superior elongation performance (>200%) compared to conventional PVC and PET matrices required for cut-and-cover applications. Figure 3 As shown, by increasing the amount of Vistamaxx 3980FL, the film elongation % was further enhanced in both the MD and TD directions. With the addition of 20% Vistamaxx 3980FL as a modifier, elongation greater than 600% was achieved in both the MD and TD directions, a performance that surpasses that of imported high-end commercial samples.

[0130] 4. Tear strength

[0131] For cutting tapes, backing films with higher tear strength can help absorb additional energy during the cutting process, reduce vibration, and enhance cutting accuracy. For example... Figure 4 As shown, by increasing the amount of Vistamaxx 3980FL, the membrane tear strength has been enhanced in both the MD and TD directions.

[0132] 5. Optical performance

[0133] After UV irradiation affects the function of the cutting strip, the adhesive strength decreases significantly. Therefore, good optical properties and light transmittance are preferred. For example... Figure 5 As shown, all three formulations exhibited low haze and good transparency.

[0134] Unless otherwise specified, the phrase “consistent with…” does not exclude the presence of other steps, elements or materials (whether or not specifically mentioned in the specification), provided that such steps, elements or materials do not affect the novel characteristics of the basis of the invention, and furthermore, they do not exclude impurities and variations generally associated with the elements and materials used.

[0135] For simplicity, only certain numerical ranges are explicitly disclosed in this document. However, a lower limit can be combined with any other upper limit to define a range that is not explicitly stated, and similarly, a lower limit can be combined with any other lower limit to define a range that is not explicitly stated; likewise, an upper limit can be combined with any upper limit to define a range that is not explicitly stated. Furthermore, even if not explicitly stated, every point or individual value between the two endpoints is included within the range. Therefore, each point or individual value itself can serve as a lower or upper limit, combined with other points or individual values ​​or other lower or upper limits to define a range that is not explicitly stated.

[0136] All prior art literature is incorporated herein by reference, provided that its disclosure does not contradict the description of this invention. Furthermore, all references and bibliographies cited herein (including experimental procedures, publications, patents, journal articles, etc.) are incorporated herein by reference, provided that their disclosure does not contradict the description of this invention.

[0137] Although the invention has been described with respect to many embodiments and examples, those skilled in the art will understand after reading this disclosure that other embodiments can be devised without departing from the scope and spirit of the invention disclosed herein.

Claims

1. A backing film for dicing tapes of semiconductor wafers, comprising a polypropylene blend, said polypropylene blend comprising 6 wt% to 30 wt% of a propylene-based elastomer and 70 wt% to 94 wt% of a propylene copolymer, based on the total weight of said polypropylene blend. The propylene-based elastomer comprises greater than 90 wt% to less than or equal to 92 wt% of propylene-derived units and greater than or equal to 8 wt% to less than 10 wt% of ethylene-derived units. Based on the total weight of the propylene-based elastomer, the heat of melting of the propylene-based elastomer is less than 80 J / g, and the melting point of the propylene-based elastomer is less than or equal to 105°C. The propylene copolymer mentioned above is PP9513.

2. The cut strip backing film according to claim 1, wherein the crystallinity of the propylene-based elastomer is 2% to 65% of the crystallinity of isotactic polypropylene.

3. The cutting strip backing film according to claim 1, wherein the graded melt flow rate (MFR) of the propylene-based elastomer is 2-20 g / 10 min.

4. The cut strip backing film according to claim 1, wherein the heat of melt of the propylene-based elastomer is from 1.0 J / g to 75 J / g.

5. The cut strip backing film according to claim 1, wherein the propylene-based elastomer has a heat of melt of 3.0 J / g to 50 J / g.

6. The cut strip backing film according to claim 1, wherein the melt heat of the propylene-based elastomer is from 6.0 J / g to 35 J / g.

7. The cut strip backing film according to claim 1, wherein the content of the propylene-based elastomer is 10 wt% to 30 wt%, and the content of the propylene copolymer is 70 wt% to 90 wt%, based on the total weight of the polypropylene blend.

8. The cut strip backing film according to claim 1, wherein the content of the propylene-based elastomer is 10 wt% to 25 wt%, and the content of the propylene copolymer is 75 wt% to 90 wt%, based on the total weight of the polypropylene blend.

9. The cutting tape backing film according to claim 1, wherein the polypropylene blend is in the form of a single-layer film or a multilayer film.

10. The cut-band backing film according to claim 1, wherein the propylene-based elastomer is Vistamaxx. TM 3980FL.

11. A polymer blend for use as a backing film for dicing tapes of semiconductor wafers, said polypropylene blend comprising 6 wt% to 30 wt% of a propylene-based elastomer and 70 wt% to 94 wt% of a propylene copolymer, based on the total weight of said polypropylene blend. The propylene-based elastomer comprises greater than 90 wt% to less than or equal to 92 wt% of propylene-derived units and greater than or equal to 8 wt% to less than 10 wt% of ethylene-derived units. Based on the total weight of the propylene-based elastomer, the heat of melting of the propylene-based elastomer is less than 80 J / g, and the melting point of the propylene-based elastomer is less than or equal to 105°C. The propylene copolymer mentioned above is PP9513.

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