Continuous fiber reinforced thermoplastic material and overmolded article comprising same

Abstract

Embodiments of the present disclosure are directed to a continuous fiber reinforced thermoplastic material comprising a polymer matrix and a plurality of continuous fibers from 50 wt% to 80 wt% of the total weight of the continuous fiber reinforced thermoplastic material. The polymer matrix comprises a polypropylene component and a polyolefin elastomer component.

Description

[0001] Claim priority

[0002] This application claims the benefit of priority of U.S. Provisional Application Serial No. 63 / 407,441, Attorney Docket No. 1202219, filed on September 16, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments of the present disclosure generally relate to thermoplastic compositions, and more particularly to continuous fiber reinforced thermoplastics having a lower flexural modulus and a desired tensile strength, and overmolded articles formed therefrom. Background Art

[0004] Continuous fiber reinforced thermoplastics can have the desired properties for overmolded articles, such as tensile strength. However, traditional continuous fiber reinforced thermoplastics may need to be preheated before being placed in a mold. Such preheating may require dedicated equipment, increasing energy costs or extending production time.

[0005] Accordingly, there is a continuing need for new and more cost-effective solutions for overmolding continuous fiber reinforced thermoplastics while providing the desired tensile strength. Summary of the Invention

[0006] Embodiments of the present disclosure relate to a continuous fiber reinforced thermoplastic material comprising a polymer matrix including a polypropylene component and a polyolefin elastomer component, which is relatively softer (i.e., has a reduced flexural modulus) compared to a similar composition consisting of a polypropylene component and continuous fibers, to allow bonding to a substrate without preheating and has a similar tensile strength.

[0007] According to one embodiment, a continuous fiber reinforced thermoplastic material is provided. The continuous fiber reinforced thermoplastic material comprises a polymer matrix and a plurality of continuous fibers accounting for 50 wt% to 80 wt% of the total weight of the continuous fiber reinforced thermoplastic material. The polymer matrix includes a polypropylene component and a polyolefin elastomer component.

[0008] According to another embodiment, a method of preparing an overmolded article is provided. The method includes contacting a continuous fiber reinforced thermoplastic material with a polymer substrate in a mold and applying heat to bond the continuous fiber reinforced thermoplastic material to the polymer substrate to form an overmolded article.

[0009] Other features and advantages of the embodiments described herein will be set forth in the detailed description below, and will be readily apparent to those skilled in the art from such description or recognized by practicing the embodiments described herein, including the following specific embodiments, claims. Brief Description of the Drawings

[0010] Figure 1 is a top - view photograph of comparative and exemplary overmolded articles after a three - point bend test, according to one or more embodiments shown and described herein;

[0011] Figure 2 is Figure 1 a side - view photograph of the article;

[0012] Figure 3 is Figure 1 a photograph of a comparative overmolded article;

[0013] Figure 4 is Figure 1 a photograph of a comparative overmolded article; and

[0014] Figure 5 is Figure 1 a photograph of an exemplary overmolded article. Detailed Description

[0015] Reference will now be made in detail to various embodiments of continuous - fiber - reinforced thermoplastics (“CFR thermoplastics”), particularly CFR thermoplastics comprising a polymer matrix and multiple continuous fibers that account for 50 wt% to 80 wt% of the total weight of the CFR thermoplastic. The polymer matrix includes a polypropylene component and a polyolefin elastomer component.

[0016] The present disclosure should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the subject matter to those skilled in the art.

[0017] Definition

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terms used in this disclosure are merely for the purpose of describing particular embodiments and are not intended to be limiting.

[0019] Herein, a range may be expressed as from “about” a particular value and / or to “about” another particular value. When expressing such a range, another embodiment includes from the said particular value and / or to the said other particular value. Similarly, when a numerical value is expressed as an approximation by use of the preposition “about”, it is understood that the particular value constitutes another embodiment. It should also be understood that each endpoint of each range is significant both in relation to and independent of the other endpoint.

[0020] Unless otherwise expressly stated, any method described herein should not be construed as requiring its steps to be performed in a particular order, nor should any device be required to have a particular orientation. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or any device claim does not actually recite an order or orientation of components, or the claims or specification do not otherwise expressly state that the steps should be limited to a particular order, or do not recite a particular order or orientation of device components, no order or orientation should be inferred in any respect. This applies to any possible basis of non-explicit interpretation, including: logical issues involving step arrangement, operational flow, component order, or component orientation; the plain meaning derived from grammatical organization or punctuation, and the number or type of embodiments described in the specification.

[0021] In this specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are also intended to include the plural forms. Thus, for example, unless the context clearly indicates otherwise, reference to "a" component includes aspects having two or more such components.

[0022] As used herein, the term "flexural modulus" refers to the ratio of stress to strain in flexural deformation measured in accordance with ASTM D790.

[0023] As used herein, the term "tensile strength" refers to the longitudinal tensile stress at break measured in accordance with ASTM D638 or the maximum stress that a material can withstand when stretched longitudinally in the direction ahead of the break.

[0024] As used herein, the term "similar tensile strength" refers to a tensile strength that differs by no more than 20% from the tensile strength of a similar composition consisting of a polypropylene component and continuous fibers. The similar composition lacks a polyolefin elastomer component.

[0025] As used herein, the term "melt flow index" refers to the ability of a material melt to flow under pressure measured in accordance with ASTM D1238 at a given temperature and a given weight.

[0026] As used herein, the term "yield tensile elongation" refers to the ratio between the increased length and the initial length at the yield point measured in accordance with ASTM D638 at 23 °C and a strain rate of 0.85 mm / s.

[0027] As used herein, the term "continuous fiber" refers to a fiber that spans all or substantially all of the dimensions of a CFR thermoplastic material. As used herein, the term "substantially all of the dimensions" means greater than 75% of the dimensions of the CFR thermoplastic material.

[0028] As described herein, the term "average diameter" refers to the average of the diameters of each of a plurality of continuous fibers.

[0029] As described herein, the term "density" refers to the mass per unit volume of a material measured at 23 °C in accordance with ASTM D792.

[0030] As described herein, the term "polyolefin elastomer (POE)" refers to a low-crystalline (i.e., crystallinity less than or equal to 25%) polymer prepared from olefin monomers.

[0031] As described herein, the term "copolymer" refers to a polymer formed when two or more different monomers are joined in the same chain.

[0032] As described herein, the term "block" refers to a portion of a macromolecule containing a number of constitutional units that has at least one characteristic not present in an adjacent portion.

[0033] As described herein, the term "preheat" or "preheating" refers to heating a CFR thermoplastic material prior to the step of applying heat to bond the CFR thermoplastic material to a polymeric substrate. Generally, "preheating" refers to heating the CFR thermoplastic material in an oven with an infrared heater or other conventional heating method before placing the CFR thermoplastic material in a mold, or heating the CFR thermoplastic material in a mold with an infrared heater or other conventional heating method before the CFR thermoplastic material contacts and bonds to the polymeric substrate.

[0034] As described above, the CFR thermoplastic material can have the desired properties for overmolded articles, such as tensile strength. However, conventional CFR thermoplastic materials may require preheating to conform the composition to the mold shape and to create a strong interfacial bond between the composition and the substrate. Such preheating may require specialized equipment.

[0035] Disclosed herein are CFR thermoplastic materials that mitigate the above problems. Specifically, the CFR thermoplastic materials disclosed herein comprise a polymer matrix and a plurality of continuous fibers that account for 50 wt% to 80 wt% of the total weight of the CFR thermoplastic material. The polymer matrix comprises a polypropylene component and a polyolefin elastomer component, which results in the CFR thermoplastic material being relatively soft (i.e., reduced flexural modulus) to allow bonding to a substrate without preheating and having a similar tensile strength compared to a similar composition consisting of a polypropylene component and continuous fibers.

[0036] The CFR thermoplastic materials disclosed herein can generally be described as comprising a polymer matrix and a plurality of continuous fibers. The plurality of continuous fibers are disposed within the polymer matrix and span all or substantially all of the dimensions of the CFR thermoplastic material.

[0037] Polymer matrix

[0038] The CFR thermoplastic material may include a minimum amount of polymer matrix (e.g., greater than or equal to 20 wt%) to ensure that there is a sufficient amount of polymer matrix to fully coat and bond together multiple continuous fibers to form the CFR thermoplastic material. The amount of polymer matrix in the CFR thermoplastic material may be limited (e.g., less than or equal to 50 wt%) to ensure a sufficient improvement in mechanical properties (e.g., tensile strength) relative to the polymer being reinforced. Thus, in an embodiment, the amount of polymer matrix in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) may be greater than or equal to 20 wt%, greater than or equal to 23 wt%, greater than or equal to 25 wt%, or even greater than or equal to 27 wt%. In an embodiment, the amount of polymer matrix in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) may be less than or equal to 50 wt%, less than or equal to 45 wt%, less than or equal to 40 wt%, less than or equal to 35 wt%, less than or equal to 33 wt%, or even less than or equal to 30 wt%. In an embodiment, the amount of polymer matrix in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) may be from 20 wt% to 50 wt%, from 20 wt% to 45 wt%, from 20 wt% to 40 wt%, from 20 wt% to 35 wt%, from 20 wt% to 33 wt%, from 20 wt% to 30 wt%, from 23 wt% to 50 wt%, from 23 wt% to 45 wt%, from 23 wt% to 40 wt%, from 23 wt% to 35 wt%, from 23 wt% to 33 wt%, from 23 wt% to 30 wt%, from 25 wt% to 50 wt%, from 25 wt% to 45 wt%, from 25 wt% to 40 wt%, from 25 wt% to 35 wt%, from 25 wt% to 33 wt%, from 25 wt% to 30 wt%, from 27 wt% to 50 wt%, from 27 wt% to 45 wt%, from 27 wt% to 40 wt%, from 27 wt% to 35 wt%, from 27 wt% to 33 wt%, or even from 27 wt% to 30 wt%, or any and all subranges formed by any of these endpoints.

[0039] The polymer matrix of the CFR thermoplastic material comprises a polypropylene component and a polyolefin elastomer component. The combination of the polypropylene component and the polyolefin elastomer component in the CFR thermoplastic material produces a softer composition with a similar tensile strength compared to a similar composition consisting of the polypropylene component and continuous fibers. The polypropylene component imparts tensile strength thereto and allows it to bond to the substrate. The polyolefin elastomer component reduces the melting point of the CFR thermoplastic material, making it softer (i.e., the flexural modulus is reduced) and allowing for overmolding without preheating the CFR thermoplastic material.

[0040] Polypropylene component

[0041] In an embodiment, the polypropylene component may comprise a polypropylene polymer. In an embodiment, the polypropylene component may comprise at least one polypropylene polymer selected from the group consisting of: polypropylene homopolymers, polypropylene impact copolymers, and polypropylene random copolymers. In an embodiment, the polypropylene polymer may comprise at least 85% propylene monomer units based on the total number of monomer units in the polypropylene polymer.

[0042] In an embodiment, the polypropylene polymer may have a melt flow index of greater than or equal to 15 g / 10 min as measured at a temperature of 230 °C under a load of 2.16 kg. In an embodiment, the melt flow index of the polypropylene polymer as measured at a temperature of 230 °C under a load of 2.16 kg may be greater than or equal to 15 g / 10 min, greater than or equal to 30 g / 10 min, greater than or equal to 50 g / 10 min, or even greater than or equal to 70 g / 10 min. In an embodiment, the melt flow index of the polypropylene polymer as measured at a temperature of 230 °C under a load of 2.16 kg may be less than or equal to 150 g / 10 min, less than or equal to 125 g / 10 min, or even less than or equal to 100 g / 10 min. In an embodiment, the melt flow index of the polypropylene polymer measured at a temperature of 230 °C under a load of 2.16 kg may be greater than 15 g / 10 min to 150 g / 10 min, 15 g / 10 min to 125 g / 10 min, 15 g / 10 min to 100 g / 10 min, 30 g / 10 min to 150 g / 10 min, 30 g / 10 min to 125 g / 10 min, 30 g / 10 min to 100 g / 10 min, 50 g / 10 min to 150 g / 10 min, 50 g / 10 min to 125 g / 10 min, 50 g / 10 min to 100 g / 10 min, 70 g / 10 min to 150 g / 10 min, 70 g / 10 min to 125 g / 10 min, or even 70 g / 10 min to 100 g / 10 min, or any and all subranges formed by any of these endpoints.

[0043] In an embodiment, the polypropylene polymer may have a tensile strength greater than or equal to 20 MPa. In an embodiment, the tensile strength of the polypropylene polymer may be greater than or equal to 20 MPa, greater than or equal to 22 MPa, greater than or equal to 24 MPa, or even greater than or equal to 26 MPa. In an embodiment, the tensile strength of the polypropylene polymer may be less than or equal to 40 MPa, less than or equal to 35 MPa, or even less than or equal to 30 MPa. In an embodiment, the tensile strength of the polypropylene polymer may be from 20 MPa to 40 MPa, from 20 MPa to 35 MPa, from 20 MPa to 30 MPa, from 22 MPa to 40 MPa, from 22 MPa to 35 MPa, from 22 MPa to 30 MPa, from 24 MPa to 40 MPa, from 24 MPa to 35 MPa, from 24 MPa to 30 MPa, from 26 MPa to 40 MPa, from 26 MPa to 35 MPa, or even from 26 MPa to 30 MPa, or any and all subranges formed by any of these endpoints.

[0044] In an embodiment, the polypropylene polymer may have a yield tensile elongation greater than or equal to 2%. In an embodiment, the yield tensile elongation of the polypropylene polymer may be greater than or equal to 2%, greater than or equal to 3%, or even greater than or equal to 4%. In an embodiment, the yield tensile elongation of the polypropylene polymer may be less than or equal to 20%, less than or equal to 15%, less than or equal to 10%, or even less than or equal to 5%. In an embodiment, the yield tensile elongation of the polypropylene polymer may be from 2% to 20%, from 2% to 15%, from 2% to 10%, from 2% to 5%, from 3% to 20%, from 3% to 15%, from 3% to 10%, from 3% to 5%, from 4% to 20%, from 4% to 15%, from 4% to 10%, or even from 4% to 5%, or any and all subranges formed by any of these endpoints.

[0045] In an embodiment, the flexural modulus of the polypropylene polymer may be greater than or equal to 1000 Mpa, or even greater than or equal to 1250 MPa. In an embodiment, the flexural modulus of the polypropylene polymer may be less than or equal to 1750 Mpa, or even less than or equal to 1500 MPa. In an embodiment, the flexural modulus of the polypropylene polymer may be from 1000 MPa to 1750 MPa, from 1000 MPa to 1500 MPa, from 1250 MPa to 1750 MPa, or even from 1250 MPa to 1500 MPa, or any and all subranges formed by any of these endpoints.

[0046] The polymer matrix may comprise a minimum amount of a polypropylene component (e.g., greater than or equal to 20 wt%) to achieve the desired tensile strength and ensure adhesion to the substrate. The amount of the polypropylene component in the polymer matrix may be limited (e.g., less than or equal to 95 wt%) to ensure a relatively soft composition. Thus, in an embodiment, the polymer matrix may comprise from 20 wt% to 95 wt% of a polypropylene component based on the total weight of the polymer matrix. In an embodiment, the amount of the polypropylene component in the polymer matrix (based on the total weight of the polymer matrix) may be greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 50 wt%, greater than or equal to 60 wt%, greater than or equal to 70 wt%, or even greater than or equal to 80 wt%. In an embodiment, the amount of the polypropylene component in the polymer matrix (based on the total weight of the polymer matrix) may be less than or equal to 95 wt%, less than or equal to 90 wt%, less than or equal to 85 wt%, less than or equal to 80 wt%, less than or equal to 75 wt%, or even less than or equal to 70 wt%. In an embodiment, the amount of the polypropylene component in the polymer matrix (based on the total weight of the polymer matrix) may be from 20 wt% to 95 wt%, from 20 wt% to 90 wt%, from 20 wt% to 85 wt%, from 20 wt% to 80 wt%, from 20 wt% to 75 wt%, from 20 wt% to 70 wt%, from 30 wt% to 95 wt%, from 30 wt% to 90 wt%, from 30 wt% to 85 wt%, from 30 wt% to 80 wt%, from 30 wt% to 75 wt%, from 30 wt% to 70 wt%, from 40 wt% to 95 wt%, from 40 wt% to 90 wt%, from 40 wt% to 85 wt%, from 40 wt% to 80 wt%, from 40 wt% to 75 wt%, from 40 wt% to 70 wt%, from 50 wt% to 95 wt%, from 50 wt% to 90 wt%, from 50 wt% to 85 wt%, from 50 wt% to 80 wt%, from 50 wt% to 75 wt%, from 50 wt% to 70 wt%, from 60 wt% to 95 wt%, from 60 wt% to 90 wt%, from 60 wt% to 85 wt%, from 60 wt% to 80 wt%, from 60 wt% to 75 wt%, from 60 wt% to 70 wt%, from 70 wt% to 95 wt%, from 70 wt% to 90 wt%, from 70 wt% to 85 wt%, from 70 wt% to 80 wt%, from 70 wt% to 75 wt%, from 80 wt% to 95 wt%, from 80 wt% to 90 wt%, or even from 80 wt% to 85 wt%, or any and all subranges formed by any of these endpoints.

[0047] In an embodiment, the amount of the polypropylene component in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) can be greater than or equal to 10 wt%, greater than or equal to 15 wt%, or even greater than or equal to 20 wt%. In an embodiment, the amount of the polypropylene component in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) can be less than or equal to 40 wt%, less than or equal to 35 wt%, or even less than or equal to 30 wt%. In an embodiment, the amount of the polypropylene component in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) can be 10 wt% to 40 wt%, 10 wt% to 35 wt%, 10 wt% to 30 wt%, 15 wt% to 40 wt%, 15 wt% to 35 wt%, 15 wt% to 30 wt%, 20 wt% to 40 wt%, 20 wt% to 35 wt%, or even 20 wt% to 30 wt%, or any and all subranges formed by any of these endpoints.

[0048] Suitable commercial embodiments of the polypropylene component are available from Braskem, such as the impact copolymer polypropylene grade C758-80NA.

[0049] Polyolefin elastomer component

[0050] In some embodiments, the polyolefin elastomer component can include a polyolefin elastomer. In an embodiment, the polyolefin elastomer component can contain at least one polyolefin elastomer selected from the group consisting of ethylene-butene random copolymer, ethylene-octene random copolymer, and ethylene-octene block copolymer.

[0051] In an embodiment, the polyolefin elastomer can be characterized by a melt flow index measured at a temperature of 190 °C under a load of 2.16 kg. In an embodiment, the melt flow index of the polyolefin elastomer measured at a temperature of 190 °C under a load of 2.16 kg can be from 5 g / 10 min to 30 g / 10 min. In an embodiment, the melt flow index of the polyolefin elastomer measured at a temperature of 190 °C under a load of 2.16 kg can be greater than or equal to 5 g / 10 min, or even greater than or equal to 10 g / 10 min. In an embodiment, the melt flow index of the polyolefin elastomer measured at a temperature of 190 °C under a load of 2.16 kg can be less than or equal to 30 g / 10 min, less than or equal to 25 g / 10 min, or even less than or equal to 20 g / 10 min. In an embodiment, the melt flow index of the polyolefin elastomer can be from 5 g / 10 min to 30 g / 10 min, from 5 g / 10 min to 25 g / 10 min, from 5 g / 10 min to 20 g / 10 min, from 10 g / 10 min to 30 g / 10 min, from 10 g / 10 min to 25 g / 10 min, or even from 10 g / 10 min to 20 g / 10 min, or any and all sub-ranges formed by any of these endpoints.

[0052] In an embodiment, the polyolefin elastomer can be characterized by the density of the polyolefin elastomer. In an embodiment, the density of the polyolefin elastomer can be 0.83 g / cm 3 to 0.91 g / cm 3 . In an embodiment, the density of the polyolefin elastomer can be greater than or equal to 0.83 g / cm 3 , greater than or equal to 0.84 g / cm 3 , greater than or equal to 0.85 g / cm 3 , or even greater than or equal to 0.86 g / cm 3 . In an embodiment, the density of the polyolefin elastomer can be less than or equal to 0.91 g / cm 3 , less than or equal to 0.90 g / cm 3 , less than or equal to 0.89 g / cm 3 , or even less than or equal to 0.88 g / cm 3 . In an embodiment, the density of the polyolefin elastomer can be 0.83 g / cm 3 to 0.91 g / cm 3 , 0.83 g / cm 3 to 0.90 g / cm 3 , 0.83 g / cm 3 to 0.89 g / cm 3 , 0.83 g / cm 3 to 0.88 g / cm 3 , 0.84 g / cm3 to 0.91 g / cm 3 、0.84 g / cm 3 to 0.90 g / cm 3 、0.84 g / cm 3 to 0.89 g / cm 3 、0.84 g / cm 3 to 0.88 g / cm 3 、0.85 g / cm 3 to 0.91 g / cm 3 、0.85 g / cm 3 to 0.90 g / cm 3 、0.85 g / cm 3 to 0.89 g / cm 3 、0.85 g / cm 3 to 0.88 g / cm 3 、0.86 g / cm 3 to 0.91 g / cm 3 、0.86 g / cm 3 to 0.90 g / cm 3 、0.86 g / cm 3 to 0.89 g / cm 3 ,or even 0.86 g / cm 3 to 0.88 g / cm 3 ,or any and all sub-ranges formed by any of these endpoints.

[0053] The polymer matrix may comprise a minimum amount (e.g., greater than or equal to 5 wt%) of a polyolefin elastomer component to ensure a reduced flexural modulus and to allow overmolding without preheating the CFR thermoplastic material. The amount of the polyolefin elastomer component may be limited (e.g., less than or equal to 80 wt%) to ensure the desired tensile strength. Thus, in an embodiment, the polymer matrix may comprise from 5 wt% to 80 wt% of a polyolefin elastomer component based on the total weight of the polymer matrix. In an embodiment, the amount of the polyolefin elastomer component in the polymer matrix (based on the total weight of the polymer matrix) may be greater than or equal to 5 wt%, greater than or equal to 10 wt%, greater than or equal to 15 wt%, greater than or equal to 20 wt%, greater than or equal to 25 wt%, or even greater than or equal to 30 wt%. In an embodiment, the amount of the polyolefin elastomer component in the polymer matrix (based on the total weight of the polymer matrix) may be less than or equal to 80 wt%, less than or equal to 70 wt%, less than or equal to 60 wt%, less than or equal to 50 wt%, less than or equal to 40 wt%, less than or equal to 30 wt%, or even less than or equal to 20 wt%. In an embodiment, the amount of the polyolefin elastomer component in the polymer matrix (based on the total weight of the polymer matrix) may be from 5 wt% to 80 wt%, from 5 wt% to 70 wt%, from 5 wt% to 60 wt%, from 5 wt% to 50 wt%, from 5 wt% to 40 wt%, from 5 wt% to 30 wt%, from 5 wt% to 20 wt%, from 10 wt% to 80 wt%, from 10 wt% to 70 wt%, from 10 wt% to 60 wt%, from 10 wt% to 50 wt%, from 10 wt% to 40 wt%, from 10 wt% to 30 wt%, from 10 wt% to 20 wt%, from 15 wt% to 80 wt%, from 15 wt% to 70 wt%, from 15 wt% to 60 wt%, from 15 wt% to 50 wt%, from 15 wt% to 40 wt%, from 15 wt% to 30 wt%, from 15 wt% to 20 wt%, from 20 wt% to 80 wt%, from 20 wt% to 70 wt%, from 20 wt% to 60 wt%, from 20 wt% to 50 wt%, from 20 wt% to 40 wt%, from 20 wt% to 30 wt%, from 25 wt% to 80 wt%, from 25 wt% to 70 wt%, from 25 wt% to 60 wt%, from 25 wt% to 50 wt%, from 25 wt% to 40 wt%, from 25 wt% to 30 wt%, from 30 wt% to 80 wt%, from 30 wt% to 70 wt%, from 30 wt% to 60 wt%, from 30 wt% to 50 wt%, or even from 30 wt% to 40 wt%, or any and all subranges formed by any of these endpoints.

[0054] In an embodiment, the amount of the polyolefin elastomer component in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) can be greater than or equal to 1 wt%, greater than or equal to 3 wt%, or even greater than or equal to 5 wt%. In an embodiment, the amount of the polyolefin elastomer component in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) can be less than or equal to 20 wt%, less than or equal to 15 wt%, or even less than or equal to 10 wt%. In an embodiment, the amount of the polyolefin elastomer component in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) can be from 1 wt% to 20 wt%, from 1 wt% to 15 wt%, from 1 wt% to 10 wt%, from 3 wt% to 20 wt%, from 3 wt% to 15 wt%, from 3 wt% to 10 wt%, from 5 wt% to 20 wt%, from 5 wt% to 15 wt%, or even from 5 wt% to 10 wt%, or any and all sub-ranges formed by any of these endpoints.

[0055] Suitable commercial embodiments of the polyolefin elastomer component are available under the INFUSE brand from Dow, such as the olefin block copolymer grade 9817.

[0056] Multiple continuous fibers

[0057] In an embodiment, multiple continuous fibers can span all or substantially all of the dimensions of the CFR composition. For example, in an embodiment, multiple continuous fibers can span all or substantially all of the length of the CFR composition. In an embodiment, each of the multiple continuous fibers can have a certain length, and the lengths of the continuous fibers in the multiple continuous fibers can be substantially parallel. For example, in an embodiment, the lengths of the continuous fibers can extend along the length of the CFR composition and be parallel to the length of the CFR composition.

[0058] In an embodiment, the multiple continuous fibers can include at least one of glass fibers, aramid fibers, basalt fibers, and carbon fibers.

[0059] In an embodiment, the average diameter of the multiple continuous fibers can be from 10 μm to 30 μm to ensure the desired tensile strength is achieved. In an embodiment, the average diameter of the multiple fibers can be greater than or equal to 10 μm, or even greater than or equal to 15 μm. In an embodiment, the average diameter of the multiple fibers can be less than or equal to 30 μm, or even less than or equal to 25 μm. In an embodiment, the average diameter of the multiple fibers can be from 10 μm to 30 μm, from 10 μm to 25 μm, from 15 μm to 30 μm, or even from 15 μm to 25 μm, or any and all sub-ranges formed by any of these endpoints.

[0060] In an embodiment, the average linear mass density of the plurality of continuous fibers can be from 4400 TEX to 276 TEX. In an embodiment, the average linear mass density of the plurality of continuous fibers can be less than or equal to 4400 TEX, less than or equal to 3600 TEX, less than or equal to 3200 TEX, less than or equal to 2800 TEX, less than or equal to 2400 TEX, less than or equal to 2000 TEX, or even less than or equal to 1600 TEX. In an embodiment, the average linear mass density of the plurality of continuous fibers can be greater than or equal to 276 TEX, greater than or equal to 400 TEX, greater than or equal to 600 TEX, greater than or equal to 800 TEX, or even greater than or equal to 1000 TEX. In an embodiment, the average linear mass density of the plurality of continuous fibers can be from 4400 TEX to 276 TEX, from 4400 TEX to 400 TEX, from 4400 TEX to 600 TEX, from 4400 TEX to 800 TEX, from 4400 TEX to 1000 TEX, from 4000 TEX to 276 TEX, from 4000 TEX to 400 TEX, from 4000 TEX to 600 TEX, from 4000 TEX to 800 TEX, from 4000 TEX to 1000 TEX, from 3600 TEX to 276 TEX, from 3600 TEX to 400 TEX, from 3600 TEX to 600 TEX, from 3600 TEX to 800 TEX, from 3600 TEX to 1000 TEX, from 3200 TEX to 276 TEX, from 3200 TEX to 400 TEX, from 3200 TEX to 600 TEX, from 3200 TEX to 800 TEX, from 3200 TEX to 1000 TEX, from 2800 TEX to 276 TEX, from 2800 TEX to 400 TEX, from 2800 TEX to 600 TEX, from 2800 TEX to 800 TEX, from 2800 TEX to 1000 TEX, from 2400 TEX to 276 TEX, from 2400 TEX to 400 TEX, from 2400 TEX to 600 TEX, from 2400 TEX to 800 TEX, from 2400 TEX to 1000 TEX, from 2000 TEX to 276 TEX, from 2000 TEX to 400 TEX, from 2000 TEX to 600 TEX, from 2000 TEX to 800 TEX, from 2000 TEX to 1000 TEX, from 1600 TEX to 276 TEX, from 1600 TEX to 400 TEX, from 1600 TEX to 600 TEX, from 1600 TEX to 800 TEX, or even from 1600 TEX to 1000 TEX, or any and all sub-ranges formed by any of these endpoints.

[0061] In an embodiment, the plurality of continuous fibers can be a tow, yarn, roving, or woven mat.

[0062] The CFR thermoplastic material may include a minimum amount of multiple continuous fibers (e.g., greater than or equal to 50 wt%) to ensure sufficient improvement in mechanical properties (e.g., tensile strength) relative to the polymer being reinforced. The amount of multiple continuous fibers in the CFR thermoplastic material may be limited (e.g., less than or equal to 80 wt%) to ensure there is a sufficient amount of polymer matrix to fully coat the multiple continuous fibers and bond them together to form the CFR thermoplastic material. Thus, in an embodiment, the CFR thermoplastic material may include 50 wt% to 80 wt% of multiple continuous fibers based on the total weight of the CFR thermoplastic material. In an embodiment, the amount of multiple continuous fibers in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) may be greater than or equal to 50 wt%, or even greater than or equal to 60 wt%. In an embodiment, the amount of multiple continuous fibers in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) may be less than or equal to 80 wt%, or even less than or equal to 70 wt%. In an embodiment, the amount of multiple continuous fibers in the CFR thermoplastic material (based on the total weight of the CFR thermoplastic material) may be 50 wt% to 80 wt%, 50 wt% to 70 wt%, 60 wt% to 80 wt%, or even 60 wt% to 70 wt%, or any and all subranges formed by any of these endpoints.

[0063] CFR thermoplastic

[0064] As described herein, the CFR thermoplastic material may have a polymer matrix that includes a polypropylene component and a polyolefin elastomer component, which results in the CFR thermoplastic material being relatively soft (i.e., reduced flexural modulus) to allow bonding to a substrate without preheating and having a similar tensile strength compared to a similar composition consisting of a polypropylene component and continuous fibers. In an embodiment, the tensile strength of the CFR composition may be within 20%, within 17%, within 15%, or even within 13% of the tensile strength of a similar composition consisting of a polypropylene component and continuous fibers.

[0065] In an embodiment, the flexural modulus of the CFR thermoplastic material can be greater than or equal to 20 GPa, greater than or equal to 23 GPa, or even greater than or equal to 25 GPa. In an embodiment, the flexural modulus of the CFR thermoplastic material can be less than or equal to 40 GPa, less than or equal to 35 GPa, or even less than or equal to 30 GPa. In an embodiment, the flexural modulus of the CFR thermoplastic material can be from 20 GPa to 40 GPa, from 20 GPa to 35 GPa, from 20 GPa to 30 GPa, from 23 GPa to 40 GPa, from 23 GPa to 35 GPa, from 23 GPa to 30 GPa, from 25 GPa to 40 GPa, from 25 GPa to 35 GPa, or even from 25 GPa to 30 GPa, or any and all subranges formed by any of these endpoints.

[0066] In an embodiment, the CFR thermoplastic material can be a tape, sheet, plate, rod, tube, or panel. As described above, the CFR thermoplastic material has a plurality of substantially parallel continuous fibers. In an embodiment, the CFR thermoplastic material can be a unidirectional tape. In an embodiment, the CFR thermoplastic material can be a ply in a laminate.

[0067] Additive

[0068] In an embodiment, the CFR thermoplastic material can further comprise additives. In an embodiment, the additives can include antioxidants, stabilizers, adhesion promoters; fungicides; anti-fogging agents; antistatic agents; foaming and blowing agents; adhesives and adhesive polymers; dispersants; flame retardants and smoke suppressants; mineral fillers; initiators; lubricants; mica; pigments, colorants, and dyes; processing aids; mold release agents; silanes, titanates / esters, and zirconates / esters; slip agents and anti-blocking agents; stearates / esters; ultraviolet absorbers; viscosity modifiers; waxes; or combinations thereof. In an embodiment, the additives can be present in the polymer matrix.

[0069] Processing

[0070] In an embodiment, the CFR thermoplastic material described herein can be manufactured by an intermittent process or a continuous process. In an embodiment, the polypropylene component and the polyolefin elastomer component of the polymer matrix can be blended during the intermittent process or the continuous process.

[0071] In an embodiment, components of the polymer matrix (including a polypropylene component and a polyolefin elastomer component) can be added to an extruder [e.g., a 27MM Leistritz twin-screw extruder (L / D 60)] and blended. In an embodiment, the blending (e.g., in the barrel of the extruder) can be carried out at a temperature in the range of 150°C to 270°C. In an embodiment, the polypropylene component and the polyolefin elastomer component of the polymer matrix can be compounded (i.e., blended together) in the extruder.

[0072] Blending (also known as compounding) devices are well known to those skilled in the art and generally include a feeding component, especially at least one hopper for powdery materials and / or at least one injection pump for liquid materials; a high-shear mixing component, such as a co-rotating or counter-rotating twin-screw extruder, usually including a feeding screw placed in a heating barrel (or tube); an output head that shapes the extrudate; and an extrudate cooling component that cools by air or by water circulation. The extrudate usually continuously comes out of the device in a rod shape and can be cut or formed into pellets. However, other forms can be obtained by assembling a die of the desired shape on the output die.

[0073] In an embodiment, the CFR thermoplastic material can be pultruded. During pultrusion, multiple continuous fibers are pulled through a polymer matrix bath or through an injection chamber where the polymer matrix is injected into the injection chamber so that the polymer matrix impregnates the multiple continuous fibers. Pultrusion can form strips, sheets, or other extruded shapes of continuous fibers impregnated with the polymer matrix.

[0074] Overmolded product

[0075] In an embodiment, the overmolded article can include the CFR thermoplastic material described herein adhered to a polymer substrate. In an embodiment, the polymer substrate can be a fiber-reinforced polypropylene substrate.

[0076] In an embodiment, a method for preparing an overmolded article can include contacting the CFR thermoplastic material as described herein with a polymer substrate to form an overmolded article. In an embodiment, the mold can be an injection mold or a compression mold.

[0077] As described herein, the polymer matrix of the CFR thermoplastic material includes a polypropylene component and a polyolefin elastomer component, which results in the CFR thermoplastic material being relatively soft (i.e., the flexural modulus is reduced) to allow adhesion to the substrate without preheating. Therefore, in an embodiment, the CFR thermoplastic material can be not preheated before the step of thermally bonding the CFR thermoplastic material to the polymer substrate.

[0078] The overmolding process may include open injection molding, direct long fiber composite (DLFT) compression molding, or glass mat thermoplastic (GMT) compression molding. In an embodiment, the overmolded article may include a generally rectangular cross-section. Those of ordinary skill in the art will understand that other geometries can be fabricated.

[0079] Examples

[0080] Table 1 below shows the sources of the components used to form Comparative Composition CC1 and Example Compositions EC1 and EC2.

[0081] Table 1

[0082]

[0083] Table 2 below shows the formulations (in wt%, based on the total weight of the polymer matrix and based on the total weight of the CFR thermoplastic material) of Comparative Composition CC1 and Example Compositions EC1 and EC2 and certain of their properties. To form Comparative Composition CC1 and Example Compositions EC1 and EC2, the components were melt blended to form articles having thicknesses of 0.20 mm, 0.20 mm, and 0.22 mm, respectively.

[0084] Table 2

[0085]

[0086] As shown in Table 2, Example Compositions EC1 and EC2 (compositions comprising C758 - 80NA (polypropylene) and INFUSE 9817 (polyolefin elastomer)) have a lower flexural modulus and similar tensile strength compared to Comparative Example CC1 (a composition comprising C758 - 80NA and no INFUSE 9817). As shown by Comparative Example CC1 and Example Compositions EC1 and EC2, CFR thermoplastics comprising a polymer matrix having a polypropylene component and a polyolefin elastomer component produce a softer composition that has a similar tensile strength compared to a similar composition consisting of a polypropylene component and no polyolefin elastomer component.

[0087] Table 3 below shows the compositions of Comparative Overmolded Articles CA1 and CA2 and Example Overmolded Articles EA1 and EA2 and certain properties after a three-point bend test with an 8-inch span in accordance with ASTM D790. To prepare the overmolded articles, panels of CFR thermoplastic material were applied to opposite surfaces of an open injection tool. For Comparative Overmolded Article CA2, which involved preheating, it was preheated before inserting it into the molding tool. After any appropriate preheating and insertion into the tool, the tool was closed and the injection process was initiated to fill the void between the two panels and form a rectangular polymer substrate.

[0088] Table 3

[0089] CA1 CA2 EA1 EA2 Composition CC1 CC1 EC1 EC2 Preheat No Yes No No Maximum load (kg) 62 118 90 93 Maximum deflection (cm) 0.7 2.7 4.3 4.5 Flexural modulus (GPa) 11.6 11.7 11.5 11.3

[0090] Now refer to Figures 1 to 5 During the three-point bending test, comparative example article CA1 (an article comprising a CFR thermoplastic material containing only a polypropylene component and not preheated) experienced delamination on the top surface. Comparative example article CA2 (an article comprising a CFR thermoplastic material containing only a polypropylene component and preheated) experienced gradual top surface compressive buckling at 1.3 cm and bottom tensile fracture at 2.5 cm. Example article EA1 (an article comprising a CFR thermoplastic material containing a polypropylene component and a polyolefin component and not preheated) experienced top surface compression and gradual top surface delamination at 0.64 cm and bottom surface delamination at 4.32 cm. Example article EA2 (an article comprising a CFR thermoplastic material containing a polypropylene component and a polyolefin component and not preheated) experienced gradual top surface compression at 4.47 cm and did not experience final fracture. It should be noted that the test apparatus used did not allow deflection to exceed 5 cm. Additionally, as shown in Table 3, example articles EA1 and EA2 (articles comprising a CFR thermoplastic material containing a polypropylene component and a polyolefin component) had a higher maximum deflection and a lower flexural modulus than comparative example articles CA1 and CA2 (articles comprising a CFR thermoplastic material containing only a polypropylene component). As shown by comparative example articles CA1 and CA2 and example articles EA1 and EA2, CFR thermoplastic materials containing a polypropylene component and a polyolefin component produced a softer composition, which had a similar tensile strength compared to a similar composition consisting of a polypropylene component and without a polyolefin elastomer component. Additionally, articles with sufficient mechanical properties (such as tensile strength) could be obtained without preheating.

[0091] As shown in Table 3, example articles EA1 and EA2 had a higher maximum load compared to comparative example articles CA1 and CA2. As shown by comparative example articles CA1 and CA2 and example articles EA1 and EA2, although CFR thermoplastic materials containing a polypropylene component and a polyolefin component produced a softer composition compared to a similar composition consisting of a polypropylene component and without a polyolefin elastomer component, including these softer compositions produced relatively strong overmolded articles.

[0092] Obviously, modifications and variations can be made without departing from the scope of the disclosure defined in the appended claims. More specifically, while some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.

Claims

1. A continuous fiber reinforced thermoplastic material, comprising: A polymer matrix, comprising: A polypropylene component, and A polyolefin elastomer component; and Multiple continuous fibers based on 50% to 80% by weight of the total weight of the continuous fiber reinforced thermoplastic material.

2. The continuous fiber reinforced thermoplastic material according to claim 1, wherein the polymer matrix comprises, based on the total weight of the polymer matrix: 20% to 95% by weight of the polypropylene component; and 5% to 80% by weight of the polyolefin elastomer component.

3. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the multiple continuous fibers span all or substantially all of the dimensions of the continuous fiber reinforced thermoplastic material.

4. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein each of the multiple continuous fibers has a certain length, and the lengths of the continuous fibers in the multiple continuous fibers are substantially parallel.

5. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the multiple continuous fibers include at least one of glass fiber, aramid fiber, basalt fiber, and carbon fiber.

6. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the average diameter of the multiple continuous fibers is 10 μm to 30 μm.

7. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the average linear mass density of the multiple continuous fibers is 4400 TEX to 276 TEX.

8. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the multiple continuous fibers are tows, yarns, rovings, or woven mats.

9. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the polypropylene component comprises a polypropylene polymer having a melt flow index measured at a temperature of 230 °C under a load of 2.16 kg greater than or equal to 15 g / 10 minutes, a tensile strength greater than or equal to 24 MPa, and a yield tensile elongation greater than or equal to 2%.

10. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the polypropylene component comprises at least one polypropylene polymer selected from the group consisting of: polypropylene homopolymer, polypropylene impact copolymer, and polypropylene random copolymer.

11. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the polypropylene component comprises a polypropylene polymer comprising at least 85% propylene monomer units based on the total number of monomer units in the polypropylene polymer.

12. The continuous fiber-reinforced thermoplastic material according to any one of the preceding claims, wherein the polyolefin elastomer component comprises a polyolefin elastomer having a melt flow index of 5 g / 10 min to 30 g / 10 min measured at a temperature of 190 °C under a load of 2.16 kg and a density of 0.83 g / cm 3 to 0.91 g / cm 3 .

13. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the polyolefin elastomer component comprises at least one polyolefin elastomer selected from the group consisting of: ethylene-butene random copolymer, ethylene-octene random copolymer, and ethylene-octene block copolymer.

14. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the continuous fiber reinforced thermoplastic material is a unidirectional tape.

15. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the continuous fiber reinforced thermoplastic material is a layer in a laminate.

16. The continuous fiber reinforced thermoplastic material according to any one of the preceding claims, wherein the tensile strength of the continuous fiber reinforced thermoplastic material differs from the tensile strength of a similar composition consisting of the polypropylene component and the continuous fibers by within 20%.

17. An overmolded article comprising: Bonding the continuous fiber reinforced thermoplastic material according to any one of the preceding claims to a polymer substrate.

18. The overmolded article according to claim 17, wherein the polymer substrate is a fiber reinforced polypropylene substrate.

19. A method for preparing an overmolded article, which comprises: Bringing the continuous fiber reinforced thermoplastic material into contact with the polymer substrate in a mold; And Applying heat to bond the continuous fiber reinforced thermoplastic material to the polymer substrate to form an overmolded article; Wherein the continuous fiber reinforced thermoplastic material comprises: A polymer matrix, which comprises: A polypropylene component, and A polyolefin elastomer component; and Multiple continuous fibers based on 50% to 80% by weight of the total weight of the continuous fiber reinforced thermoplastic material.

20. The method for preparing an overmolded article according to claim 19, wherein the continuous fiber reinforced thermoplastic material is not preheated before the step of applying heat to bond the continuous fiber reinforced thermoplastic material to the polymer substrate.

21. The method for preparing an overmolded article according to claim 19 or 20, wherein the mold is an injection mold or a compression mold.

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