Polyamide 56 blend composition with reduced hygroscopicity

Abstract

A polyamide 56 blend composition includes a polyamide 56 polymer and a low hygroscopic polyphthalamide. The polyamide 56 blend composition may also be made from a polyamide 56 copolymer and a low hygroscopic polyphthalamide. The polyamide 56 blend composition can be molded into various articles.

Description

Technical Field

[0001] This invention relates to polyamide 56 blend compositions with reduced hygroscopicity. Background Technology

[0002] Polyamides (also known as nylon) are among the most widely used thermoplastic materials due to their physical properties. Polyamides are polymers with repeating units linked by amide bonds, produced, for example, through the condensation of diacids and diamines. They exhibit good abrasion and wear resistance, as well as high chemical and corrosion resistance. In addition to UV resistance, polyamides also possess flexibility and low density. Conventional polyamides are generally easy to mold. Given these properties, polyamides play an important role in many automotive, electrical, and consumer product applications.

[0003] Because many conventional polyamides are made from fossil fuels that emit carbon dioxide and contribute to global warming, there is a growing trend towards using bio-based polyamides. Examples of bio-based polyamides include, but are not limited to, polyamide 56 and polyamide 1010. While bio-based polyamides have beneficial properties, many of these bio-based polyamides exhibit higher hygroscopicity compared to conventional polyamides. For example, polyamide 56 shares many similar properties with polyamide 66 but has significantly higher hygroscopicity. Hygroscopicity can lead to a loss of tensile strength and modulus due to the interaction of moisture with the polyamide polymer chains. Products made from bio-based polyamides may also experience a loss of electrical properties and dimensional stability due to hygroscopicity.

[0004] Polymer blending is a method of creating novel materials by blending polymers together to achieve properties and characteristics that may not be present in any single base polymer. Typically, the blended polymers should be compatible with each other to achieve the desired new properties.

[0005] In an article published in e-Polymers, Shouyun Zhang describes a blend of bio-based polyamide 56 and polyethylene terephthalate (PET). Zhang, Shouyun. (2023). e-Polymers 2023:23:20228082. Based on experimental results, Zhang concludes that the blend of polyamide 56 and PET exhibits poor performance due to the lack of compatibility between the two polymers.

[0006] Chinese Patent No. CN111825975B (attributed to Kasai Shanghai Biotechnology Co., Ltd.), published on September 12, 2022, describes a polyamide composition and a method for preparing the composition. The polyamide composition comprises 100 parts of polyamide 56, 10-30 parts of long-chain polyamide, and 5-50 parts of additives. The long-chain polyamide is a polyamide in which the number of methylene groups between adjacent amide groups on the main chain is greater than or equal to 10. The additives include at least mineral fillers selected from the group consisting of talc, calcium carbonate, barium sulfate, mica powder, and kaolin.

[0007] Chinese Patent No. CN115260756B (owned by Suzhou SunwayPolymer Co.), published on June 11, 2024, describes a halogen-free, flame-retardant, bio-based, high-temperature resistant nylon alloy / polyphenylene ether composite material. The material described in this patent is a mixture of polyamide 56, polyamide 10T, polyphenylene ether, flame retardant, toughening agent, nucleating agent, antioxidant, and lubricant. The patent describes this composite material as achieving excellent heat resistance, low moisture absorption, excellent alcohol resistance, and excellent flame retardancy.

[0008] He et al. described improvements in the moisture resistance and thermal properties of bio-based polyamides. He, Lulu & An, Taofang & He, Min & Fan, Qiao & Yang, Jifei & Liu, Yufei & Qin, Shuhao & Yu, Jie. (2023) Journal of Applied Polymer Science, 140. 10.1002 / app.54301. Moisture resistance and high thermal properties were achieved in bio-based polyamide 56 / F-based heat-resistant compound through crystal regulation. The improved properties were obtained by incorporating two heat-resistant agents. The two heat-resistant agents used were (N-(4-F-phenylmaleimide)-styrene) alternating copolymer (PFS) and (N-(4-F-phenylmaleimide)-tracelyl isocyanurate) alternating copolymer (PFT). The moisture resistance of the polyamide 56 and PFS compound was improved by 14.6% compared to polyamide 56 alone. The moisture resistance of the polyamide and PFT composites is improved by 15.5% compared to polyamide 56 alone. The authors note that these composites could be used in the automotive industry.

[0009] Nevertheless, polyamide 56 blends with reduced hygroscopicity are still needed. Summary of the Invention

[0010] One embodiment relates to a polyamide 56 blend composition comprising polyamide 56 and low-hygroscopic polyphthalamide.

[0011] Another embodiment relates to an article made from a polyamide 56 blend composition comprising polyamide 56 and low-hygroscopic polyphthalamide.

[0012] Another embodiment relates to a polyamide 56 blend composition comprising a polyamide 56 copolymer and a low-hygroscopic polyphthalamide.

[0013] Another embodiment relates to an article made from a polyamide 56 blend comprising a polyamide 56 copolymer and a low-hygroscopic polyphthalamide.

[0014] Other features and advantages of the invention will become apparent from the following more detailed description of preferred embodiments taken in conjunction with the accompanying drawings, which illustrate the principles of the invention by way of example. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form a part of this specification, schematically illustrate one or more illustrative embodiments of the invention and, together with the overview given above and the detailed description given below, serve to explain the principles of the invention, wherein:

[0016] Figure 1 The results show the water absorption rate of polyamide 56 blended with different concentrations of low-hygroscopic polyphthalamide.

[0017] Figure 2 The results show the water absorption of polyamide 56 copolymers blended with various concentrations of low-hygroscopic polyphthalamide, compared to polyamide 56 and conventional polyamide 66. Detailed Implementation

[0018] The description of illustrative embodiments of the invention is intended to be interpreted with reference to the accompanying drawings, which should be considered an integral part of the entire written description. Any references to orientation or direction in the description of embodiments of the invention disclosed herein are intended only for convenience of description and are not intended to limit the scope of the invention in any way. Relative terms such as “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “upper,” “lower,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the orientation as described therein or as shown in the drawings discussed. These relative terms are for convenience of description only and do not require the device to be constructed or operated in a particular orientation unless explicitly stated otherwise. Unless otherwise explicitly stated, terms such as “attach,” “fixed,” “connected,” “coupled,” “interconnected,” etc., refer to a relationship in which structures are directly or indirectly fastened or attached to each other through intermediate structures, and both movable and rigid attachments or associations.

[0019] Furthermore, the features and benefits of the present invention are described with reference to preferred embodiments. Therefore, the present invention should be explicitly limited to such embodiments that illustrate possible non-limiting combinations of features that may exist individually or in combination with other features; the scope of the invention is defined by the appended claims.

[0020] The polyamide 56 blend composition of the present invention comprises a bio-based polyamide resin and a bio-based polyamide copolymer resin. The bio-based polyamide resin can be prepared using a polycondensation process of diamines and diacids of different chain lengths. The polyamide 56 resin is polymerized from bio-based 1,5-diaminopentane and fossil-based adipic acid. Furthermore, the polyamide 56 resin can be further modified with comonomers to form a polyamide 56 copolymer resin. Examples of commercially available polyamide 56 resins that can be used in the present invention include: ECOBLEND N56F (from Shanghai Kumho Sunny Plastics Co., Ltd.), BIONYLAC100-NC002 (from Kingfa Sci. & Tech. Co., Ltd.), and BIONYLA R30G0001 (from Kingfa Sci. & Tech. Co., Ltd.). An exemplary polyamide 56 copolymer resin that can be used in the present invention is ECOPENT 6631 (from Cathay Biotech, Inc.).

[0021] In addition to polyamide 56, the polyamide 56 blend composition also contains a low-hygroscopic polyphthalamide. The low-hygroscopic polyphthalamide has a saturated water absorption rate of less than 5% by weight when immersed in water according to the ISO 62 water absorption test. Polyphthalamide is a polyamide in which residues of terephthalic acid or isophthalic acid, or a combination of both, constitute at least 55 molar percentages of the dicarboxylic acid portion of the repeating structural unit in the polymer chain (ASTM D5336). The low-hygroscopic polyphthalamide that can be used in the polyamide 56 blend composition can be and is defined as any polyphthalamide having a lower water absorption rate when both are tested using the same test conditions compared to polyamide 56 alone. Preferably, the low-hygroscopic polyphthalamide is a condensation product of a monomer comprising at least an aliphatic diamine and at least one aromatic dicarboxylic acid. The low-hygroscopic polyphthalamide can also be made with other comonomers that serve functions such as lowering the processing temperature.

[0022] Examples of low-hygroscopic polyphthalamides that can be used in polyamide 56 blends include, but are not limited to, polyamide 6T, polyamide 9T, polyamide 10T and polyamide 10T copolymers, such as PA10TX, all of which are made from terephthalic acid monomers containing terephthalamide.

[0023] Polyamide 10T is poly(decamethylene terephthalamide) which has the following structure:

[0024]

[0025] An example of commercially available polyamide 10T is VICNYL R6100 (from Kingfa Sci. & Tech. Co., Ltd.). An example of commercially available polyamide 10TX is VICYNL 2700 EB (from Kingfa Sci. & Tech. Co., Ltd.).

[0026] Preferably, polyamide 10TX is used as a low-hygroscopic polyphthalamide in the polyamide 56 blend composition. Polyamide 10TX has a similar processing temperature to polyamide 56 resin, which makes it easier to mold compared to polyamide 56 blend compositions using polyamide 10T.

[0027] The low-hygroscopic polyphthalamide accounts for about 20% by weight or less of the polyamide 56 blend composition. Preferably, the low-hygroscopic polyphthalamide is in the range of about 3% by weight to about 10% by weight of the polyamide 56 blend composition, and more preferably, in the range of about 5% by weight to about 10% by weight of the polyamide 56 blend composition.

[0028] Other conventional additives can be incorporated into polyamide 56 blends. Examples of conventional additives include: pigments, dyes, pore-forming agents, antistatic agents, foaming agents, plasticizers, free radical scavengers, anti-blocking agents, dust repellents, antifouling agents, surfactants, slip additives, optical brighteners, viscosity modifiers, gloss improvers, dispersion stabilizers, UV stabilizers, UV absorbers, antioxidants (such as phenolic or amine antioxidants), lubricants, processing aids, heat stabilizers, hydrolysis stabilizers, crosslinking activators, coupling agents, radiation opacifiers (e.g., but not limited to barium sulfate), tungsten metal, non-oxide bismuth salts, colorants, reinforcing agents, impact strength modifiers, compatibilizers, flame retardants, and any combination thereof. Conventional amounts of these additives may be included.

[0029] Polyamide 56 resin can be blended with low-hygroscopic polyphthalamide to form polyamide 56 blend compositions. The mixing equipment can be any suitable equipment used in the field of mixing concentrated solids. Examples of such suitable equipment include: batch mixers, such as Brabender mixers and Banbury mixers, single extruders, twin-screw extruders, high-speed centrifugal mixers, etc.

[0030] Polyamide 56 blends can be molded into various articles using molding methods commonly used for thermoplastic resin compositions, including but not limited to injection molding, injection compression molding, extrusion molding, compression molding, blow molding, calendering, or casting. In particular, injection molding is the preferred molding method from the perspectives of ease of molding, mass production efficiency, and cost.

[0031] Polyamide 56 blend compositions can be molded into a variety of different parts. For example, the compositions can be molded into seals, gaskets, connectors, housings, wires, cables, printed circuit boards or EMI shielding, and other electronic or computer components. The compositions can be used to manufacture electronic components such as smartphones, general automotive parts, electric motors, e-powertrains, batteries and battery housings, chargers for electric vehicles, and other components for electric vehicles. Additionally, the compositions of the present invention can be used to manufacture molded parts. Furthermore, the polyamide 56 blend compositions of the present invention can also be used to manufacture medical devices, surgical equipment, medical encapsulations, or wearable medical devices. Moreover, the polyamide 56 blend compositions of the present invention can be used to manufacture any product that bears a load or has a mechanical function.

[0032] Example

[0033] Various samples of polyamide 56 blends were prepared using polyamide 56 and low-hygroscopic polyphthalamide. All samples were prepared on a TSM D6 / 2 Brabender extruder with a 42 mm parallel counter-rotating twin-screw. The extruder temperature varied from about 250°C to about 305°C depending on the blend.

[0034] Once the materials are mixed together in a twin-screw extruder as described above, they are then injection molded into 60×60×1 mm sample plates using a 130-ton SE-D molding machine with a 28 mm screw diameter and a single-cavity test die. The injection temperature is approximately 285°C to 315°C, and the die temperature is approximately 80°C.

[0035] Example 1 serves as a control sample. In this example, only polyamide 56 resin was used, and no other materials were blended with the polyamide 56 resin. The polyamide 56 resin was BIONYLA C100-NC002 (from Kingfa Sci. & Tech. Co., Ltd.).

[0036] Example 2 is a sample containing polyamide 56 resin blended together to form a polyamide 56 blend composition and 5% by weight of polyamide 10T. The polyamide 56 resin used in this sample is BIONYLA C100-NC002 (from KingfaSci.&Tech. Co., Ltd.). The polyamide 10T used in this sample is VICNYL R6100 (from KingfaSci.&Tech. Co., Ltd.).

[0037] Example 3 is a sample containing polyamide 56 resin blended together to form a polyamide 56 blend composition and 10% by weight of polyamide 10T. The polyamide 56 resin used in this sample is BIONYLA C100-NC002 (from KingfaSci.&Tech. Co., Ltd.). The polyamide 10T used in this sample is VICNYL R6100 (from KingfaSci.&Tech. Co., Ltd.).

[0038] Example 4 is a sample containing polyamide 56 resin blended together to form a polyamide 56 blend composition and 5% by weight of polyamide 10TX. The polyamide 56 resin used in this sample is BIONYLA C100-NC002 (from KingfaSci.&Tech. Co., Ltd.). The polyamide 10TX used in this sample is VICYNL 2700 EB (from KingfaSci.&Tech. Co., Ltd.).

[0039] Example 5 is a sample containing polyamide 56 resin blended together to form a polyamide 56 blend composition and 10% by weight of polyamide 10TX. The polyamide 56 resin used in this sample is BIONYLA C100-NC002 (from KingfaSci.&Tech. Co., Ltd.). The polyamide 10TX used in this sample is VICYNL 2700 EB (from KingfaSci.&Tech. Co., Ltd.).

[0040] The water absorption rates of the samples from Examples 1 through 5 were then tested according to ASTM D570 (October 12, 2022) and ISO 62:2008. The samples were dried at 210℉ (98.9℃) for 8 hours. The dried samples (measurement size 60 × 60 × 1 mm) of each composition were immersed in water at room temperature of approximately 25℃. The percentage of water absorption was measured as a function of time. The percentage of saturated water absorption and the percentage reduction in water absorption for each example were then calculated compared to the control in Example 1.

[0041] Figure 1 This is a graph showing the percentage of water absorption (as a function of time) for each of the tested embodiments. The data shows that, when using the required amount of low-hygroscopic polyphthalamide, the water absorption rate of the polyamide 56 blend composition is lower than that of polyamide 56 alone. Figure 1 This indicates that the polyamide 56 blend composition has reduced hygroscopicity compared to polyamide 56 alone.

[0042] The table below shows the percentage of saturated water absorption and the percentage of water absorption reduction compared to the control (i.e., Example 1).

[0043] Example saturated water absorption percentage Percentage reduction in water absorption 1 15.17 0 2 12.85 15.49 3 12.15 20.03 4 13.39 11.90 5 12.62 16.98

[0044] The data in the table show that using the required amount of low-hygroscopic polyphthalamide in polyamide 56 blends results in a reduction in water absorption compared to polyamide 56 resin alone.

[0045] In the next series of embodiments, polyamide 66 resin, polyamide 56 resin, polyamide 56 copolymer resin, and various blends of polyamide 56 copolymer with low hygroscopic polyphthalamide are used.

[0046] Example 6 is a single polyamide 56. The polyamide 56 resin is BIONYLA C100-NC002 (from KingfaSci.&Tech. Co., Ltd.). Example 7 is a single polyamide 56 resin copolymer. The polyamide resin copolymer is ECOPENT 6631 (from Cathay Biotech, Inc.). Example 8 is a single polyamide 66. The polyamide 66 resin is VYDYNE 21SPF (from Ascend Performance Materials).

[0047] Example 9 is a polyamide 56 blend composition comprising a polyamide 56 copolymer and 5% by weight of polyamide 10T. The polyamide 56 copolymer resin is ECOPENT 6631 (from Cathay Biotech, Inc.). The polyamide 10T used in Example 9 is VICNYL R6100 (from Kingfa Sci. & Tech. Co., Ltd.). Example 10 is a polyamide 56 blend composition comprising a polyamide 56 copolymer and 10% by weight of polyamide 10T. The polyamide 56 copolymer resin is ECOPENT 6631 (from Cathay Biotech, Inc.). The polyamide 10T used in Example 12 is VICNYL R6100 (from Kingfa Sci. & Tech. Co., Ltd.).

[0048] Moisture content tests were also performed on Examples 6 through 10 according to ASTM D570 (October 12, 2022) and ISO 62:2008. Samples were dried at 210℉ (98.9℃) for 8 hours. The dried samples (measurement dimensions 60 × 60 × 1 mm) were then immersed in water at room temperature (approximately 25℃). The percentage of water absorption was measured as a function of time. Both the saturated water absorption percentage and the percentage reduction in water absorption were calculated for each example.

[0049] Figure 2 This is a graph showing the percentage of water absorption (as a function of time) for each of Examples 6-10 tested. The data shows that the polyamide 56 blend composition comprising the polyamide 56 copolymer and polyamide 10T has a similar percentage of saturated water absorption as conventional polyamide 66. Additionally, the data shows that the polyamide copolymer has a lower percentage of saturated water absorption compared to polyamide 56 resin alone.

[0050] The table below shows the percentage of saturated water absorption and the percentage of water absorption reduction of the polyamide 56 blend composition compared to the control (i.e., Example 6).

[0051] Example saturated water absorption percentage Percentage reduction in water absorption 6 10.91 0 9 10.22 6.25 10 8.98 17.67

[0052] These data show that polyamide 56 blends containing polyamide 56 copolymer and polyamide 10T have an improved percentage reduction in water absorption compared to polyamide 56 copolymer alone.

[0053] All these examples demonstrate that the percentage reduction in water absorption is significantly higher than the concentration of low-hygroscopic polyphthalamide in the polyamide 56 blend composition. Unwilling to be bound by this, it is believed that this unexpected result is due to the morphological changes of the materials when blended together.

[0054] Those skilled in the art will understand that the invention can be used in various modifications to its structure, arrangement, proportions, dimensions, materials, and components without departing from its principles, and can be practiced in other ways particularly suited to specific environments and operational requirements. Therefore, the currently disclosed embodiments are to be considered illustrative rather than restrictive in all respects, and the scope of the invention is defined by the appended claims and is not limited to the foregoing description or embodiments.

Claims

1. A polyamide 56 blend composition comprising a polyamide 56 polymer and a low-hygroscopic polyphthalamide.

2. The composition according to claim 1, wherein the low-hygroscopic polyphthalamide is a condensation product comprising a monomer comprising at least an aliphatic diamine and at least one aromatic dicarboxylic acid.

3. The composition according to claim 1, wherein the low hygroscopic polyphthalamide is poly(decamethylene terephthalamide) or a copolymer thereof.

4. The composition according to claim 1, wherein the low-hygroscopic polyphthalamide accounts for less than 20% by weight of the polyamide 56 blend composition.

5. The composition according to claim 1, wherein the low hygroscopic polyphthalamide accounts for about 3% to about 10% by weight of the polyamide 56 blend composition.

6. The composition according to claim 1, wherein the low hygroscopic polyphthalamide accounts for about 5% to about 10% by weight of the polyamide 56 blend composition.

7. An article made of a polyamide 56 blend comprising polyamide 56 or a polyamide 56 copolymer and a low-hygroscopic polyphthalamide.

8. The article of claim 7, wherein the low-hygroscopic polyphthalamide is a condensation product comprising a monomer comprising at least an aliphatic diamine and at least one aromatic dicarboxylic acid.

9. The article of claim 7, wherein the low-hygroscopic polyphthalamide is poly(decamethylene terephthalamide) or a copolymer thereof.

10. The article of claim 7, wherein the low-hygroscopic polyphthalamide accounts for about 3% to about 10% by weight of the polyamide 56 blend composition.

11. The article of claim 7, wherein the low hygroscopic polyphthalamide accounts for about 5% to about 10% by weight of the polyamide 56 blend composition.

12. A polyamide 56 blend composition comprising a polyamide 56 copolymer and a low-hygroscopic polyphthalamide.

13. The composition of claim 12, wherein the hygroscopic polyphthalamide is a condensation product comprising a monomer comprising at least an aliphatic diamine and at least one aromatic dicarboxylic acid.

14. The composition of claim 12, wherein the low-hygroscopic polyphthalamide accounts for less than 20% by weight of the polyamide 56 blend composition.

15. The composition of claim 12, wherein the low-hygroscopic polyphthalamide accounts for about 3% to about 10% by weight of the polyamide 56 blend composition.

16. The composition of claim 12, wherein the low-hygroscopic polyphthalamide accounts for about 5% to about 10% by weight of the polyamide 56 blend composition.

17. The composition of claim 12, wherein the hygroscopic polyphthalamide is poly(decamethylene terephthalamide) or a copolymer thereof.

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