Cross-linked polyphenylene sulfide ether resin and the protective shell made therefrom

Abstract

This application discloses a cross-linked PPS resin, which obtains a cross-linked PPS resin with an overall cross-linking degree of not less than 32% through the cooperation of the PPS resin, cross-linking auxiliaries, and cross-linking agents, which not only retains the chemical resistance properties of the PPS resin, but also improves the heat resistance properties of the PPS film, and the heat melting resistance temperature can reach more than 380°C. In some embodiments, the cross-linked PPS resin is also provided with good flame retardancy by adding a flame-retardant agent to the raw material. The present application also discloses a protective shell for protecting electronics, which is made of the cross-linked PPS resin.

Description

Atty. Docket No. 69572WO01 (71906-WO)Cross-linked polyphenylene sulfide ether resin and the protective shell made therefromRelated Applications

[0001] The present application claims the benefit of Chinese Patent Application No. 202411533352.3, filed October 30, 2024. The entirety of Chinese Patent Application No. 202411533352.3 is expressly incorporated herein by reference.Technical Field

[0002] The present application relates to the field of resin, in particular to a crosslinked polyphenylene sulfide ether resin and a protective shell made therefrom.Background

[0003] Polyphenylene sulfides (PPS) have the advantages of mechanical performance, heat and chemical resistance. The PPS resin can avoid the erosion of the electrolyte and has low water absorption and good dimensional stability so that it can be used for the protection housing, battery, power supply and peripheral safety structures of electric products.Summary

[0004] The present application provides a cross-linked polyphenyl sulfide ether resin that also has a high melting temperature, based on maintaining the chemical resistance of the polyphenylene sulfide ether resin material.

[0005] This application provides a cross-linked PPS resin in a first aspect, with a total degree of cross-linking of the cross-linked PPS resin not less than 32%.

[0006] According to the first aspect described above, the cross-linked PPS resin comprises: PPS (polyphenylene sulfide) resin, cross-linking auxiliaries, and crosslinking agents.

[0007] According to the first aspect described above, the cross-linking auxiliaries comprise a PBT (polybutylene terephthalate) resin or a PA (polyamide) resin.Atty. Docket No. 69572WO01 (71906-WO)

[0008] According to the first aspect described above, the PA resin includes at least one of long chain nylon and / or derivatives thereof, aromatic nylon, and / or derivatives thereof.

[0009] According to the first aspect described above, the PA resin comprises PA6 or PA66.

[0010] According to the first aspect described above, the weight percentage of the PPS resin is: 37~87%, the weight percent of said cross-linking auxiliaries is: 10~30%, and the weight percent of the cross-linking agents is: 3~10%.

[0011] According to the first aspect described above, the said cross-linked PPS resin is obtained by irradiation cross-linking after extrusion and molding of various raw materials.

[0012] According to the first aspect described above, the cross-linked PPS resin further comprises: a flame-retardant agent, wherein the weight percentage of the flame-retardant agent is 2~10%.

[0013] According to the first aspect described above, the cross-linked PPS resin further comprises: a filler, wherein the weight percent of the filler is 0~50%.

[0014] According to the first aspect described above, the filler is selected from one or more combinations of glass fibers, glass beads, mineral powders, etc.

[0015] According to the first aspect described above, the melting temperature of the cross-linked PPS resin is not less than 380°C.

[0016] In a second aspect, the present application provides a protective housing for protecting electronic devices, wherein the protective housing is made of the crosslinked PPS resin according to any one of the embodiments of the first aspect.

[0017] Other features, advantages, and embodiments of the present application may be set forth or become apparent from consideration of the following detailed description of embodiments, drawings, and claims. Furthermore, it should be understood that the above summary of the invention and the following detailed description of embodiments are exemplary and are intended to provide further explanation without limiting the scope of the claimed application. It should also be understood that, although specific component arrangements are disclosed and illustrated in these exemplary embodiments, other arrangements are also within theAtty. Docket No. 69572WO01 (71906-WO) scope of the present application. However, the detailed description of embodiments and specific examples only indicate preferred embodiments of the present application. Various variations and modifications within the spirit and scope of the present application will become apparent to those skilled in the art from the detailed description of embodiments.Brief Description of the Drawings

[0018] FIG. 1 is a structural schematic diagram of an electrical device comprising the cross-linked PPS resin according to one embodiment of the present application.Detailed Description

[0019] Various specific embodiments of the present application will be described below with reference to the accompanying drawings that form a part of the present specification. It should be understood that while terms denoting orientation, such as “front,” “rear,” “upper,” “lower,” “left,” “right,” “top,” “bottom,” “inside,” “outside,” etc., are used in the present application to describe various exemplary structural parts and elements of the present application, these terms are used herein for convenience of illustration only and are determined based on the exemplary orientations shown in the accompanying drawings. Since the examples disclosed in the present application may be disposed in different orientations, these terms denoting orientation are for illustrative purposes only and should not be considered as limiting.

[0020] In the present application, unless otherwise specified, all equipment and materials may be purchased from the market or are commonly used in the industry. The methods in the following examples, unless specifically stated, are conventional methods in this field.

[0021] Polyphenylene sulfide (PPS) resin materials are a commonly used plastic materials, which have good chemical resistance, good creep resistance, high hardness, high abrasion resistance, good dimensional stability, and very low water absorption, making them well suited for use in materials such as housings. And the PPS resin materials have very good heat resistance properties, such as their melting temperature generally greater than 260°C.Atty. Docket No. 69572WO01 (71906-WO)

[0022] In order to meet the lightweight and miniaturization development requirements of electrical parts, such as power adapters and batteries, it is desirable to manufacture thinner PPS films. However, for a thinner PPS film, it needs to have a higher melting temperature to prevent the PPS film material from becoming locally or even completely melted when it is heated, resulting in thinning or deformation, or even breakage of the PPS film material.

[0023] The inventors of the present application have further found that, in general, increasing the degree of cross-linking of PPS film material can significantly raise its melting temperature. However, the cross-linking performance of the general PPS resin is poor. Regardless of whether we choose irradiation cross-linking or thermal oxygen cross-linking, its cross-linking degree is less than 15%. Although the melting temperature of the PPS film increases slightly after cross-linking, it is still generally below 300 °C.

[0024] This application provides a cross-linked PPS resin, which obtains a crosslinked PPS resin with an overall cross-linking degree of not less than 32% through the cooperation of the PPS resin, cross-linking auxiliaries, and cross-linking agents, which not only retains the chemical resistance properties of the PPS resin, but also improves the heat resistance properties of the PPS film, and the heat melting resistance temperature can reach more than 380°C. In some embodiments, the cross-linked PPS resin is also provided with good flame retardancy by adding a flame-retardant agent to the raw material.

[0025] The cross-linked PPS resin of this application includes a PPS resin, crosslinking auxiliaries, and cross-linking agents. The weight percentage of the PPS resin is 37~87%, the weight percentage of the cross-linking auxiliaries is 10~30%, and the weight percentage of the cross-linking agents is 3~10%.

[0026] In some embodiments, the cross-linking auxiliaries comprise a PBT (polybutylene terephthalate) resin or a PA (polyamide) resin. In some specific embodiments, the PA resin includes at least one of long chain nylon and / or derivatives thereof, aromatic nylon, and / or derivatives thereof. In some more specific embodiments, the PA resin (i.e. , nylon) comprises either PA6 or PA66.Atty. Docket No. 69572WO01 (71906-WO)

[0027] In some embodiments, the cross-linking agents are cross-linking agents suitable for an irradiation cross-linking reaction. In some embodiments, the crosslinking agent is selected from at least one of amide-based cross-linking agents, acrylate-based cross-linking agents, alkyne-based cross-linking agents, and polyolefin-based cross-linking agents. In certain specific embodiments, the crosslinking agent is selected from one or more of the following: diallyl adipate, diallyl sebacate, triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), 1 ,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate, methyl-triallyl isocyanurate (TMAIC), trimethylolpropane trimethacrylate (TMPTMA), pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate (TMPTA), allyl methacrylate, N,N'-m-phenylenedimaleimide, N,N-dimethylacrylamide, 2,4- hexadiyne-1 , 6-di(buty I carbamate), and 1 ,2-polybutadiene oligomers. In more specific embodiments, the cross-linking agent is an acrylate-based cross-linking agent and amide-based cross-linking agent, for example, selected from one or more of the following: triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), methyl triallyl isocyanurate (TMAIC), trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, propyl methacrylate, N,N'-m-phenylenedimaleimide, and N,N- dimethylacrylamide.

[0028] In some embodiments, the cross-linked PPS resin further comprises a flameretardant agent having a weight percent of 2~10%. The flame retardant is selected from one or more combinations of ammonium polyphosphate (APP), or a derivative thereof, melamine polyphosphate (MPP), or a derivative thereof, piperazine pyrophosphate (PAPP), or a derivative thereof, and organic hypophosphite, or a derivative thereof. The addition of a flame-retardant agent to the cross-linked PPS resin is able to render the cross-linked PPS resin flame-retardant.

[0029] In some embodiments, the cross-linked PPS resin further includes a filler selected from one or more combinations of glass fibers, glass beads, mineral powders, etc., having a weight percent of 0~50%. In some embodiments, the mineral powder may be talc, calcium carbonate, barium sulfate, wollastonite, diatomaceous earth,Atty. Docket No. 69572WO01 (71906-WO) mica, and other inorganic powders. The filler may be selectively added to the crosslinked PPS resin to further improve its rigidity.

[0030] In one embodiment of the method of obtaining a cross-linked PPS resin according to this application, the cross-linked PPS resin is obtained by irradiation cross-linking after extrusion and molding of the PPS resin, the cross-linking auxiliaries, and the cross-linking agents. In some embodiments, the irradiation cross-linking is performed at the irradiated dose of 60KGy~120KGy.

[0031] In some specific embodiments, the method of preparing the cross-linked PPS resin comprises the steps of:

[0032] a. Weighing each raw material according to its weight percentage and adding them into a mixing device for blending;

[0033] b. Extrusion, injection molding, mold pressing, etc., the mixture obtained from Step a into a sheet shape;

[0034] c. Irradiation-cross-linking the sheet obtained from Step b to obtain the crosslinked PPS resin.

[0035] The cross-linked PPS resin of this application utilizes the PPS resin as a substrate, utilizing cross-linking auxiliaries that are prone to cross-linking reactions so that the cross-linking auxiliaries and the PPS resin tangulate over the molecular chain to form a cross-linking mesh structure, thereby facilitating the cross-linking of the resin. Moreover, by controlling the content of the PPS resin and the content of the crosslinking auxiliary, the cross-linked PPS resin obtained in this application can retain the chemical resistance of the PPS resin itself, so that the cross-linked PPS resin can be used as a protective housing of electrical appliance or protective housing / peripheral safety structure of new energy battery, etc. When the cross-linking auxiliary includes PBT resin or PA resin, the cross-linking auxiliary has a particularly good effect on promoting the overall cross-linking reaction of the cross-linked PPS resin system, the overall cross-linking degree in the system is improved to no less than 32%, and the melting temperature of the PPS resin is greatly increased to no less than 380°C. As such, the cross-linked PPS resin of this application can both retain the properties of the PPS resin and improve the melting temperature so that the cross-linked PPS resinAtty. Docket No. 69572WO01 (71906-WO) does not deform easily when subjected to heat, thereby providing the cross-linked PPS resin with better reliability and wider use.

[0036] And the cross-linked PPS resins of this application can also have good flameretardant properties by adding flame-retardant agents, making cross-linked PPS resin suitable for wider use.

[0037] Further, the cross-linked PPS resin of this application uses an irradiation cross-linking method for cross-linking, which is particularly well suited to facilitate cross-linking of the PPS resin system using cross-linking auxiliaries.

[0038] The effect of the cross-linked PPS resin of this application is illustrated below by some of the cross-linked PPS resin samples of Example 1 -11 and some of the samples of the Comparative Example 1 -10. Table 1 shows the content of each component in the sample of Example 1-11 , Table 2 shows the content of each component in the sample of Comparative Example 1 -10, and Table 3 shows the performance data of the sample of examples 1 -11 and Comparative Example 1-10.

[0039] In Example 1 -11 and in Comparative Example 1-10, samples made by the irradiation cross-linking method were prepared by the following methods:

[0040] a. Weigh the raw materials according to the components and weight percentages shown in Table 1 and Table 2, and add all the raw materials into a mixing device for blending;

[0041] b. Extrusion, injection molding, or mold pressing of the mixture obtained in Step a between 280-300°C;

[0042] c. Irradiation-cross-linking the molded sample obtained from Step b to obtain the sample, and cut the sample to a standard test piece of 0.8 mm thickness for performance testing.

[0043] In the Comparative Example 1 -10, samples made by the thermal oxygen cross-linking method were prepared by the following methods:

[0044] a. Weigh the raw materials according to the components and weight percentages shown in Table 2, and add all the raw materials into a mixing device for blending;

[0045] b. The mixture was allowed to sit in hot air at 150°C-280°C for 48h-300h.Atty. Docket No. 69572WO01 (71906-WO)

[0046] The PPS resin, PC (polycarbonate) resin, ABS (acrylonitrile-styrene- butadiene copolymer) resin, PBT resin, and PA resin in Example 1-11 and Comparative Example 1 -10 are commercially available conventional resins. The cross-linking agent used in irradiated cross-linking reaction and in the thermal oxygen cross-linking reaction in various embodiments and comparative examples is an N,N'- m-phenylenedimaleimide cross-linking agent. The filler in Embodiment 10 is glass fiber, and the filler in Embodiment 11 is glass fiber.

[0047] The flame-retardant performance was tested based on UL-94 test standards. The chemical resistance test was done in 150°C transformer oil. All tests were obtained from testing of 0.8 mm resin samples.Table 1 The components in Example 1-11 and their weight percentagesAtty. Docket No. 69572WO01 (71906-WO)Table 2 Components in Comparative Example 1-10 and their weight percentagesTable 3 Resin Performance of Example 1-11 and Comparative Example 1-10Atty. Docket No. 69572WO01 (71906-WO)

[0048] As can be seen from Table 1 to Table 3 above, cross-linked PPS resin samples of Example 1 -11 of this application have a cross-linking degree of more than 32%. Moreover, due to the high degree of cross-linking, the heat resistance of the crosslinked PPS resin samples of Example 1 -11 was also relatively good, and there was no melting softening phenomenon at 380°C for 5 min. Moreover, in cross-linked PPS resin samples of Examples 7-9 with the addition of flame-retardant agent, the cross-linked PPS resin samples also had flame-retardant property and were able to reach the grade of V-0 at a thickness of 0.8 mm. In the cross-linked PPS resin of Example 10-11 with the addition of filler, the bending modulus of the cross-linked PPS resin sample was greatly increased, indicating that the rigidity of the cross-linked PPS resin sample was greatly increased. Further, the cross-linked PPS resin sample of Example 1 -11 of this application retained the chemical resistance of the PPS resin.

[0049] For resin samples of Comparative Example 1 -4, the PPS resin was also used as the resin substrate, thus maintaining the chemical resistance of the PPS resin. However, in Comparative Example 1-4, whether irradiation cross-linking or thermal oxygen cross-linking was used, the cross-linking degrees were not very high, theAtty. Docket No. 69572WO01 (71906-WO) cross-linking degrees were not higher than 15%, and the heat resistance capacity cannot meet the requirements of 380°C.

[0050] It can be seen from the resin samples of Comparative Example 5 and Comparative Example 6 that both PBT resin alone and PA resin alone are more susceptible to cross-linking, with a cross-linking degree of 42% and 49%, respectively. At a higher cross-linking degree, the heat resistance capacity can meet the requirements of 380°C. However, PBT and PA resins have insufficient chemical resistance to meet chemical resistance requirements even after cross-linking.

[0051] Comparative Example 7 and Comparative Example 8 are resin samples crosslinked with PC resin as substrate and Comparative Example 9 and Comparative Example 10 are resin samples with ABS resin as substrate. It can be seen from the Comparative Example 7-10 that the cross-linking auxiliaries PBT resin and PA resin do not have a particularly good effect on PC resin and ABS resin in facilitating crosslinking. As can be seen, the cross-linking auxiliaries PBT resin and PA resin are particularly well suited to facilitate cross-linking of the PPS resin.

[0052] It can be seen from comparison of Example 1 -11 and Comparative Example 1 -10 that the ability of the PPS resin to cross-link without the use of PBT resin and PA resin is limited, and it is difficult to reach a high degree of cross-linking whether by thermal oxygen cross-linking or by irradiation cross-linking. By adding PBT resin or PA resin to the raw materials and conducting the irradiation cross-linking reaction, the PPS resin is able to synergize with the PBT resin or PA resin to form a cross-linked mesh structure, which not only improves the cross-linking of the resin to meet heat resistance requirements, but also retains the chemical resistance and other properties of the PPS resin.

[0053] FIG. 1 is a structural schematic diagram of an electrical device comprising the cross-linked PPS film according to one embodiment of the present application. As shown in FIG. 1 , the electrical device 100 includes a protective housing 101 and an electronic component 102 disposed within the protective housing 101. The electronic device 102 is indicated by the dashed box. The protective housing 101 is made from a cross-linked PPS resin sample of any of Example 1 -11. The protective housing 101Atty. Docket No. 69572WO01 (71906-WO) surrounds the exterior of the electronic component 102, thereby enabling the protective housing 101 to protect the electronic component 102.

[0054] By using the cross-linked PPS resin of the present application as the protective housing 101 for the electronic component 102, the protective housing 101 is prevented from softening or deforming even when the electronic component 102 generates localized heat, thereby improving the reliability of the protective housing 101 in electrically insulating and protecting the electronic component 102. The electronic component 102 of the present application may be a high-heat-generating part, such as a battery.

[0055] The cross-linked PPS resin of the present application has multiple beneficial technical effects. At least some of these technical effects are listed as follows:

[0056] 1. The chemical resistance and dimensional stability of the PPS resin are preserved to enable the cross-linked PPS resin to be used in the protective housing of the electrical equipment.

[0057] 2. Halogen-free flame-retardant agent was used so that the cross-linked PPS resin is environmentally friendly.

[0058] 3. The addition of flame-retardant agent enables cross-linked PPS resin to have excellent flame-retardant property, thus meeting the requirements for miniaturization and light-weighting of electrical components and can be applied to more electronics.

[0059] 4. Excellent heat resistance increases the melting temperature of the crosslinked PPS resin, making it less prone to deformation under heat, thereby improving reliability and expanding its range of applications.

[0060] 5. The use of irradiation cross-linking simplifies the cross-linking process, making the cross-linked PPS resin easier to process and form.

[0061] Although the present disclosure has been described in connection with the exemplary examples outlined above, various alternatives, modifications, variations, improvements, and / or substantial equivalents, whether known or foreseeable now or in the near future, may be apparent to those having at least ordinary skill in the art. Therefore, the exemplary examples of the present disclosure set forth above are intended to be illustrative and not limiting. Various changes may be made withoutAtty. Docket No. 69572WO01 (71906-WO) departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to include all known or earlier developed alternatives, modifications, variations, improvements and / or substantial equivalents. The technical effects and technical problems in this specification are exemplary and not limiting. It should be noted that the examples described in this specification may have other technical effects and may solve other technical problems.

Claims

Atty. Docket No. 69572WO01 (71906-WO)Claims1. A cross-linked PPS resin, wherein the total cross-linking degree of the cross-linked PPS resin is not less than 32%.

2. The cross-linked PPS resin of claim 1 wherein the composition comprises: PPS (polyphenylene sulfide) resin; cross-linking auxiliaries; and cross-linking agents.

3. The cross-linked PPS resin of claim 2, wherein the cross-linking auxiliaries include a PBT (polybutylene terephthalate) resin or a PA (polyamide) resin.

4. The cross-linked PPS resin of claim 3, wherein the PA resin includes at least one of long chain nylon and / or derivatives thereof, aromatic nylon, and / or derivatives thereof.

5. The cross-linked PPS resin of claim 4, wherein the PA resin includes PA6 or PA66.

6. The cross-linked PPS resin of claim 2, wherein: the weight percent of the PPS resin is 37~87%; the weight percentage of the cross-linking auxiliary is 10~30%; and the weight percentage of the cross-linking agent is 3~10%.

7. The cross-linked PPS resin of claim 2, wherein the said cross-linked PPS resin is obtained by irradiation cross-linking after extrusion and molding of various raw materials.

8. The cross-linked PPS resin of claim 2, further comprising a flameretardant agent, wherein the weight percentage of the flame-retardant agent is 2~10%.Atty. Docket No. 69572WO01 (71906-WO)9. The cross-linked PPS resin of claim 2, further comprising a filler, wherein the weight percent of the filler is 0~50%.

10. The cross-linked PPS resin of claim 9, wherein the filler is selected from one or more combinations of glass fibers, glass beads, mineral powders, etc.

11. The cross-linked PPS resin of claim 1 , wherein the melting temperature of the cross-linked PPS resin is not less than 380°C.

12. A protective housing for an electronic device, wherein the protective housing is made using the cross-linked PPS resin of any one of claims 1-11.

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