High-airtightness nano injection molding polybutylene terephthalate composite material and application thereof

Abstract

The invention belongs to the field of composite materials, and discloses a high-airtightness nano injection molding polybutylene terephthalate composite material and application thereof. The composite material comprises the following components in percentage by weight: 23%-82.5% of PBT (Polybutylece Terephthalate); 5%-15% of polyarylester; 2%-8% of a reactive flexibilizer; 0.5 to 2% of an ionomer; 0-1% of an antioxidant; 0-1% of a release agent; 10%-50% of glass fiber; the PBT composite material provided by the invention can realize high and stable air tightness, and also has high aluminum alloy binding force and good mechanical properties. Meanwhile, the preparation method disclosed by the invention is simple and feasible, and is suitable for large-scale production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of composite materials, and particularly relates to a high-air-tightness nano-injection-molded polybutylene terephthalate composite material and application thereof. BACKGROUND

[0002] In recent years, nano-injection-molded middle frames have become mainstream processes for high-end mobile phones. Whether aluminum alloy middle frames, stainless steel middle frames, or titanium alloy middle frames, nano-injection-molding processes can be used to achieve the design of antenna partition strips. Polybutylene terephthalate (PBT) is the most commonly used plastic material in the nano-injection-molding process due to its good overall performance. In addition, polyphenylene sulfide (PPS) and high-temperature polyamide (PPA) are also used in some products. A mainstream trend in mobile phone design is to have increasingly higher waterproof and dustproof levels to meet the needs of more diverse use scenarios. For example, the iPhone 16 has the highest IP68 level. It is found in production that the waterproof performance of existing nano-injection-molding materials is very unstable, often with large fluctuations, which can reduce product yield and reduce the degree of freedom of structural design. Since waterproof testing is relatively complex, waterproof performance and air tightness have been proven to have a strong positive correlation in actual production. Therefore, in actual product development, the industry often uses air tightness testing to screen materials and structural designs in the early stages. SUMMARY

[0003] To overcome the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a high-air-tightness nano-injection-molded polybutylene terephthalate composite material that can achieve high and stable air tightness, while also having high aluminum alloy adhesion and good mechanical properties. The problem that current nano-injection-molding materials cannot achieve good air tightness is solved.

[0004] Another purpose of the present application is to provide a preparation method for the high-air-tightness nano-injection-molded polybutylene terephthalate composite material described above.

[0005] Still another purpose of the present application is to provide the application of the high-air-tightness nano-injection-molded polybutylene terephthalate composite material described above in smart phones and consumer electronic products.

[0006] The purposes of the present application are achieved by the following solutions:

[0007] A high-air-tightness nano-injection-molded polybutylene terephthalate composite material includes the following components in the following weight percentages:

[0008]

[0009] Preferably, the high-air-tightness nano-injection-molding polybutylene terephthalate composite material comprises the following components by weight percentage:

[0010]

[0011] Preferably, the PBT has an intrinsic viscosity of 0.6-0.8 dL / g.

[0012] Preferably, the PAR is a powder raw material, and the particle size is preferably less than 100 mesh.

[0013] Preferably, the reactive toughening agent is a glycidyl ether-containing toughening agent, preferably ethylene-methyl acrylate-glycidyl methacrylate copolymer, and the weight percentage is preferably 3%-6%.

[0014] Preferably, the ionomer is ethylene-acrylic acid-zinc-acrylate copolymer or ethylene-acrylic acid-sodium-acrylate copolymer, and the weight percentage is preferably 0.5-1.5%. Further preferably, the ionomer is ethylene-acrylic acid-zinc-acrylate copolymer.

[0015] The antioxidant is at least one of hindered phenolic antioxidant and phosphite, and is preferably antioxidant 1010.

[0016] The release agent is at least one of polyvinyl alcohol and long-chain fatty acid ester, and is preferably PETS.

[0017] A preparation method of the above-mentioned high-air-tightness nano-injection-molding polybutylene terephthalate composite material, comprising the following steps: mixing the components and extruding and granulating through an extruder, and the granulating temperature is 220-280℃.

[0018] The above-mentioned high-air-tightness nano-injection-molding polybutylene terephthalate composite material is used in the manufacture of mobile phones and consumer electronic products, and is particularly used in the preparation of nano-injection-molding aluminum alloy middle frames.

[0019] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0020] The PBT composite material of the present application can achieve high and stable air tightness, high aluminum alloy bonding force, and good mechanical properties. At the same time, the preparation method of the present application is simple and easy to implement, and is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The structure of a plastic test whole piece is shown in the figure, wherein 1 represents an aluminum alloy part, and 2 represents a plastic part.

[0022] Figure 2 The structure of a plastic aluminum alloy test whole piece used for air tightness test is shown in the figure. DETAILED DESCRIPTION

[0023] The present application is further described in detail by the following examples and drawings, but the embodiments of the present application are not limited thereto. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not mentioned by the manufacturer, which are all conventional products that can be purchased on the market. The specific conditions are as follows: the brand of the commercially available PBT / PET in Comparative Example 1 is Toray 2107G, PBT1 is Changchun Chemical 1200-211D (intrinsic viscosity 0.75 dL / g), PBT2 is Lansheng Chemical PBT1100A (intrinsic viscosity 1.05 dL / g), PETG is SK Chemical S2008, PCTG is SK Chemical JN100, PAR is Unitika U-100, glass fiber is Chongqing International ECS3031H, ethylene methyl acrylate glycidyl methacrylate copolymer is Arkema AX8900, ionomer 1 is DuPont Surlyn9320, ionomer 2 is DuPont Surlyn8920, antioxidant 1010 is Tianjin Li'anlong 1010, and release agent pentaerythritol tetra stearate (PETS) is purchased from Hubei Longxin Chemical Co., Ltd. The substances used in the examples are directly used without any treatment after purchase. The PAR particles in the examples are the PAR particles without any treatment after purchase, and the PAR powder is the ground PAR after purchase.

[0024] The tensile strength in the following examples is tested by the ISO527 standard method, and the notched impact strength is tested by the ISO180 standard method.

[0025] The aluminum alloy nano-injection sample used in the present application is prepared by the following process: 6063 aluminum alloy material, size specification, length 45 mm, width 18 mm, thickness 1.6 mm; surface treatment process: sequentially immersed in NaOH solution alkaline washing (1 mol / L, 40℃, 10 seconds), hydrochloric acid corrosion (1.2 mol / L, 30℃, 30 seconds), and ammonia solution (1.5 mol / L, 30℃, 4 minutes), and then the immersed sample is cleaned with water, dried, to obtain an aluminum alloy sample with nano-pores on the surface.

[0026] The preparation of the plastic aluminum alloy test overall piece used in the present application: the plastic metal test overall piece in the present application is prepared by referring to the method of Japanese Dacheng nano-injection related patent (8057890). The specific conditions are as follows: Figure 1 The structure diagram of the aluminum alloy plastic test overall piece, the size of the aluminum alloy piece is 18 mm x 45 mm x 1.6 mm, the size of the plastic part is 10 mm x 45 mm x 3 mm, and the bonding area of the plastic and the aluminum alloy is 0.5 cm 2In all experiments, the injection molding was kept the same injection molding conditions, barrel temperature 250-280℃, mold temperature 150℃, the plastic composite was injected onto the aluminum alloy sheet to obtain the plastic aluminum alloy test whole piece.

[0027] Plastic metal bonding force performance test: the plastic metal bonding force test standard used in the present application refers to the standard in Japanese Da Cheng Chemical Patent 8057890, the plastic and metal bonding area is 0.5cm 2 The plastic metal test whole piece was subjected to bidirectional tensile test.

[0028] The preparation of plastic aluminum alloy test whole piece used in air tightness test is as follows: Figure 2 The structure is a schematic diagram, the size of the aluminum alloy sheet is 18mmx45mmx1.6mm, and the plastic part is a circle with a diameter of 60mm and a thickness of 2mm. The plastic part is combined with the aluminum alloy by injection molding, the barrel temperature is 250-280℃, and the mold temperature is 150℃. The test equipment is Zhongke Keyi ZQJ-3000, and the test gas is helium.

[0029] Examples 1-7 and Comparative Examples 1-6

[0030] The PBT composite materials in Comparative Examples 2-6 and Examples 1-7 were prepared by the following steps: the components were weighed according to the weight percentage, then the components were mixed, and the PBT composite was granulated by a double screw extruder, and the granulation temperature was 220-280℃. The weight percentage (%) of each component in Comparative Examples 1-6 and Examples 1-7 and the properties of the obtained PBT composite materials are shown in Table 1.

[0031] Table 1. Effect of PAR and ionomer on product properties of PBT composite material

[0032]

[0033] From the comparison of Comparative Example 1 and Comparative Example 2, it can be seen that the addition of ionomer in the PBT / PET system does not improve the mechanical properties, bonding force and air tightness of the composite material; but as shown in Examples 5-6, after replacing the PBT / PET system with PBT / PAR system, not only the tensile strength is improved, but also the bonding force and air tightness are significantly improved; in addition, the comparison of Examples 5-6 with Comparative Examples 3, 5 and 6 shows that the type of polymer added in PBT also affects the properties of the obtained composite material, when PET, PETG, PCTG and other polyesters are added, the air tightness of the obtained composite material is much smaller than that when PAR is added. And when the particle size of PAR is reduced, the mechanical properties, air tightness and bonding force of the obtained composite material are significantly improved.

[0034] From the data in Table 1, the air tightness and air tightness stability of the composite material using the PAR and ionomer formulation system are obviously higher than the mainstream nano-injection PBT composite material formulation system (main component PBT / PET) on the market. Especially when the PAR powder, zinc salt ionomer and low viscosity PBT are preferably used, the performance of the material is better.

[0035] Examples 8-15

[0036] The PBT composite materials in Examples 8-15 are prepared by the following steps: weighing the components by percentage by weight, then mixing the components, and granulating by a twin-screw extruder to obtain the PBT composite, the granulation temperature is 220-280℃. The percentage by weight (%) of each component in Examples 8-15 and the properties of the PBT composite materials prepared are shown in Table 2.

[0037] Table 2. Effect of PAR and ionomer content on the product properties of PBT composite materials

[0038]

[0039]

[0040] Comparing Example 6, Examples 8-11, it can be seen that with the increase of the amount of PAR, the mechanical properties, the bonding force and the air tightness all increase first and then decrease; comparing Example 6, Examples 12-15, it can be seen that with the increase of the amount of ionomer, the air tightness and the bonding force also increase first and then decrease. Therefore, from the data in Table 2, it can be seen that both PAR and ionomer need to have a suitable amount of addition, too little or too much addition will not achieve the ideal effect. The percentage by weight of PAR is preferably 6-15%, and the amount of ionomer is preferably 0.5-2%.

[0041] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A high airtightness nano-injection molded polybutylene terephthalate composite material, characterized in that... The components include the following weight percentages:

2. The high airtightness nano-injection molded polybutylene terephthalate composite material according to claim 1, characterized in that... The components include the following weight percentages:

3. The high airtightness nano-injection molded polybutylene terephthalate composite material according to claim 1 or 2, characterized in that: The intrinsic viscosity of the PBT is 0.6-0.8 dL / g.

4. The high airtightness nano-injection molded polybutylene terephthalate composite material according to claim 1 or 2, characterized in that: The PAR is a powdered raw material with a particle size of less than 100 mesh.

5. The high airtightness nano-injection molded polybutylene terephthalate composite material according to claim 1 or 2, characterized in that: The reactive toughening agent is a toughening agent containing glycidyl ether, preferably a copolymer of ethylene methyl acrylate methacrylate glycidyl ether.

6. The high airtightness nano-injection molded polybutylene terephthalate composite material according to claim 1 or 2, characterized in that: The ionomer is a copolymer of ethylene acrylate zinc acrylate or ethylene acrylate sodium acrylate; preferably, the ionomer is ethylene acrylate zinc acrylate.

7. The high airtightness nano-injection molded polybutylene terephthalate composite material according to claim 1 or 2, characterized in that: The antioxidant is at least one of hindered phenolic antioxidants and phosphites, preferably antioxidant 1010; The release agent is at least one of polyvinyl alcohol and long-chain fatty acid esters, preferably PETS.

8. A method for preparing a high airtightness nano-injection molded polybutylene terephthalate composite material according to any one of claims 1-7, characterized in that... Includes the following steps: The components are mixed and extruded into granules using an extruder at a temperature of 220-280℃.

9. The application of a high airtightness nano-injection molded polybutylene terephthalate composite material according to any one of claims 1-7 in the manufacture of mobile phones and consumer electronics products.

10. The application of the high airtightness nano-injection molded polybutylene terephthalate composite material according to any one of claims 1-7 in the preparation of nano-injection molded aluminum alloy frames.

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