Low-dielectric flat glass fiber, low-dielectric flat glass fiber reinforced PBT composite material and preparation method of PBT composite material

Abstract

The invention provides a low-dielectric flat glass fiber reinforced PBT (polybutylene terephthalate) composite material which comprises the following raw materials in parts by weight: 50-80 parts of PBT resin, 20-50 parts of low-dielectric flat glass fibers, 0-3 parts of a lubricant and 0-5 parts of an antioxidant. The invention also provides a preparation method of the low-dielectric flat glass fiber reinforced PBT composite material and the low-dielectric flat glass fiber. According to the low-dielectric flat glass fiber reinforced PBT composite material provided by the invention, the glass fibers with a specific ratio and a specific structure are introduced, so that the PBT composite material has the characteristics of low dielectric property, warping resistance, high strength and high fluidity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to low-dielectric flat glass fiber, low-dielectric flat glass fiber reinforced PBT composite material and a preparation method of the PBT composite material. BACKGROUND

[0002] With the advent of the 5G era, the communication transmission frequency of electronic products is getting higher and higher, especially with the development and application of industrial internet and self-driving cars, the requirements for low delay and low loss of radar parts, communication antennas and housings and other parts related to high-frequency signal transmission are getting higher and higher. In order to realize low delay and low loss, materials with lower dielectric constant and dielectric loss are needed. Modified plastics become the first choice of materials for some high-frequency signal transmission parts due to their high mechanical strength, low density and high cost performance. However, most of the modified plastics currently reduce the dielectric loss and dielectric constant of the material by adding fillers, and the fillers are usually selected from substances such as silicon-containing mineral powder and hollow microbeads that do not have an aspect ratio, which can greatly reduce the mechanical strength of the material. Some cases use low-dielectric glass fiber to reduce dielectric loss and dielectric constant, but traditional low-dielectric glass fiber can reduce dielectric constant and dielectric loss, but cannot meet the warping characteristics of the material at the same time, so additional anti-warping fillers are usually added to achieve anti-warping.

[0003] Chinese patent with publication number CN116200009A provides a low-warping low-dielectric PBT composite material and a preparation method thereof, which contains 20-62 parts of a thermoplastic polyester resin composition, 1-10 parts of an olefin copolymer, 1-10 parts of a toughening agent, 15-35 parts of glass fiber and 10-30 parts of silicon powder and other raw materials. The product has excellent low-warping and low-dielectric properties; however, the product uses conventional glass fiber as the strength filler, and silicon powder as the low-dielectric filler, so the strength and low-dielectric fillers are two materials, which faces the disadvantage of relatively complex material selection and process route, and because the silicon powder does not have an aspect ratio, the mechanical strength of the composite material is greatly reduced, so it cannot well balance the mechanical properties, warping and low dielectricity.

[0004] A Chinese patent with publication number CN111234478A provides a low-dielectric glass fiber reinforced PBT composite material and a preparation method thereof. The material comprises PBT resin, polytetrafluoroethylene micro powder, filler, end-capping agent, low-dielectric glass fiber, antioxidant, and lubricant. The low-dielectric glass fiber reinforced PBT composite material effectively reduces the dielectric constant and dielectric loss factor of the PBT composite material while maintaining the strength of the glass fiber reinforced PBT material, and ensures no appearance defects such as floating fibers and product gloss, meeting the ROHS environmental protection standard. The PBT composite material of the patent uses ordinary low-dielectric glass fiber, although it achieves low-dielectric performance and maintains a certain strength, but the patent cannot achieve good dimensional stability, and the flowability of the material is relatively poor, so it is not mentioned that the product cannot balance the warpage resistance and high flowability characteristics, and the types of raw materials and additives are as high as 7, and the production process is relatively complex.

[0005] Therefore, it is of great significance to provide a glass fiber reinforced PBT composite material with high mechanical strength, high flowability, low warpage, low dielectric constant, and low dielectric loss. SUMMARY

[0006] The technical problem solved by the present application is to provide a low-dielectric flat glass fiber reinforced PBT composite material. The PBT composite material provided by the present application maintains high glass fiber content while balancing the high flowability, low warpage, low dielectric constant, and low dielectric loss of the PBT composite material.

[0007] Therefore, the present application provides a low-dielectric flat glass fiber reinforced PBT composite material. The raw materials include, by weight:

[0008] PBT resin 50-80 parts, low-dielectric flat glass fiber 20-50 parts, lubricant 0-3 parts, antioxidant 0-5 parts;

[0009] The low-dielectric flat glass fiber comprises, by mass percent: SiO2 60-65%, Al2O3 10-19%, B2O3 16-26%, Li2O 0.6-2%, CaO 0-5%, MgO 0-8%, F2 0-2%, Fe2O3 0-0.4%, Na2O 0-0.2%, and K2O 0-0.2%.

[0010] In some embodiments, the PBT resin has a melt index of 15-45 g / 10 min under test conditions of 250°C / 2.16 kg.

[0011] In some embodiments, the low-dielectric flat glass fiber has a dielectric constant of 4.2-5.0 and a dielectric loss of ≤0.005 under a test frequency of 10 GHz.

[0012] In some embodiments, the low dielectric flat glass fiber has an aspect ratio of 2:1 to 5:1.

[0013] In some embodiments, the lubricant comprises one or more of pentaerythritol stearate, ethylene bis-stearamide, silicone, and polytetrafluoroethylene.

[0014] In some embodiments, the antioxidant comprises one or more of a hindered phenolic antioxidant and a phosphite antioxidant.

[0015] In some embodiments, the low dielectric flat glass fiber has a content of 30 to 40 parts.

[0016] The application also provides a preparation method of the low dielectric flat glass fiber reinforced PBT composite material, comprising the following steps:

[0017] According to the weight ratio, the PBT resin, the lubricant, and the antioxidant are mixed to obtain a premix;

[0018] The premix is added to the main feeding port of the twin-screw extruder, and the low dielectric flat glass fiber is added to the side feeding port of the twin-screw extruder. After shearing by the screw, the premix and the low dielectric flat glass fiber are mixed, extruded, and cooled to form a low dielectric flat glass fiber reinforced PBT composite material.

[0019] In some embodiments, the preparation method of the low dielectric flat glass fiber is as follows:

[0020] According to the component ratio of the low dielectric flat glass fiber, the ingredients are mixed to obtain a mixture;

[0021] The mixture is melted to obtain a glass liquid;

[0022] The glass liquid is passed through a flat nozzle bushing to obtain a low dielectric flat glass fiber after drawing.

[0023] The application also provides a low dielectric flat glass fiber. According to the mass percentage, the raw materials comprise: SiO2 60-65%, Al2O3 10-19%, B2O3 16-26%, Li2O 0.6-2%, CaO 0-5%, MgO 0-8%, F2 0-2%, Fe2O3 0-0.4%, Na2O 0-0.2%, and K2O 0-0.2%.

[0024] The application provides a low-dielectric flat glass fiber reinforced PBT composite material, raw materials of which include: 50-80 parts of PBT resin, 20-50 parts of low-dielectric flat glass fiber, 0-3 parts of lubricant and 0-5 parts of antioxidant; in the PBT composite material, the low-dielectric flat glass fiber with specific components is introduced, so that the low-dielectric constant and low dielectric loss of the PBT composite material are ensured, and the introduction of the glass fiber is beneficial to improving the warpage resistance of the PBT composite material; therefore, the low-dielectric flat glass fiber reinforced PBT composite material provided by the application introduces the glass fiber with specific morphology and specific components, so that the mechanical properties of the PBT composite material are improved on the basis of adding high content of glass fiber, and high fluidity, low warpage, low dielectric constant and low dielectric loss are considered at the same time. DETAILED DESCRIPTION

[0025] In order to further understand the application, the preferred embodiments of the application are described below in combination with examples, but it should be understood that the description is only for further illustrating the features and advantages of the application, and is not a limitation on the claims of the application.

[0026] In view of the fact that the glass fiber reinforced PBT composite material in the prior art has various additives and complex process, and cannot simultaneously consider the properties of high mechanical property, low dielectric, warpage resistance, high fluidity, the application provides a low-dielectric flat glass fiber reinforced PBT composite material, which meets the performance requirements of high glass fiber content, low dielectric constant, low dielectric loss, high mechanical property, low warpage and high fluidity of the glass fiber reinforced PBT composite material by introducing specific low-dielectric flat glass fiber, and the amount of additive is small and the preparation process is simple. Specifically, the application discloses a low-dielectric flat glass fiber reinforced PBT composite material, raw materials of which include, according to weight parts:

[0027] 50-80 parts of PBT resin, 20-50 parts of low-dielectric flat glass fiber, 0-3 parts of lubricant and 0-5 parts of antioxidant;

[0028] The low-dielectric flat glass fiber includes, according to mass percentage: 60-65% of SiO2, 10-19% of Al2O3, 16-26% of B2O3, 0.6-2% of Li2O, 0-5% of CaO, 0-8% of MgO, 0-2% of F2, 0-0.4% of Fe2O3, 0-0.2% of Na2O and 0-0.2% of K2O, and the total of the raw materials in the low-dielectric flat glass fiber is 100%.

[0029] The PBT resin, i.e. polybutylene terephthalate, has a melt index of 15-45 g / 10 min under the test condition of 250℃ / 2.16 kg. The content of the PBT resin is 50-80 parts, specifically, the content of the PBT resin is 55-75 parts, more specifically, the content of the PBT resin is 59-72 parts, more specifically, the content of the PBT resin is 60-69 parts, and more specifically, the content of the PBT resin is 62-67 parts.

[0030] The low dielectric flat glass fiber as a reinforcing additive of the PBT composite material determines the performance of the PBT composite material to a certain extent. In the present application, the low dielectric flat glass fiber has a dielectric constant of 4.2-5.0 and a dielectric loss of ≤0.005 under a test frequency of 10 GHz. The flat glass fiber with the above dielectric constant and dielectric loss is conducive to making the PBT composite material have low dielectric constant and low dielectric loss. The content of the low dielectric flat glass fiber is 20-50 parts, specifically, the content of the low dielectric flat glass fiber is 25-45 parts, more specifically, the content of the low dielectric flat glass fiber is 28-41 parts, more specifically, the content of the low dielectric flat glass fiber is 31-40 parts, and more specifically, the content of the low dielectric flat glass fiber is 33-38 parts.

[0031] Further, the low dielectric flat glass fiber comprises, by mass percentage, SiO2 60-65%, Al2O3 10-19%, B2O3 16-26%, Li2O 0.6-2%, CaO 0-5%, MgO 0-8%, F2 0-2%, Fe2O3 0-0.4%, Na2O 0-0.2%, K2O 0-0.2%, and the total of the raw materials in the low dielectric flat glass fiber is 100%. The content of each raw material is based on the total mass of each component.

[0032] In the low dielectric flat glass fiber, the content of SiO2 is 61-64%, more specifically, the content of SiO2 is 62-63%; the content of Al2O3 is 11-17%, more specifically, the content of Al2O3 is 11-14%; the content of B2O3 is 19-26%, more specifically, the content of B2O3 is 20-25%; the content of Li2O is 0.7-1.7%, more specifically, the content of Li2O is 0.8-1.6%; the content of CaO is 0-4%, more specifically, the content of CaO is 0-3%; the content of MgO is 0-6.5%, more specifically, the content of MgO is 0-4.5%; the content of F2 is 0-1.7%, more specifically, the content of F2 is 0-1.4%; the content of Fe2O3 is 0-0.3%, more specifically, the content of Fe2O3 is 0-0.2%; the content of Na2O is 0-0.18%, more specifically, the content of Na2O is 0-0.15%; the content of K2O is 0-0.18%, more specifically, the content of K2O is 0-0.15%.

[0033] In the present application, the low dielectric flat glass fiber has a flat fiber cross-sectional structure with an aspect ratio of 2:1-5:1, specifically, the aspect ratio is 3:1-4:1; the glass fiber with such structure is beneficial to improve the warpage resistance of the PBT composite material.

[0034] The low dielectric flat glass fiber reinforced PBT composite material provided by the present application can also add an additive lubricant and an antioxidant, the lubricant includes one or more of pentaerythritol stearate, ethylene bis-stearamide, silicone and polytetrafluoroethylene, specifically, the lubricant is selected from one or more of pentaerythritol stearate, ethylene bis-stearamide, silicone and polytetrafluoroethylene; the amount of the lubricant is 0-3 parts, specifically, the amount of the lubricant is 0.5-2 parts, more specifically, the amount of the lubricant is 1-1.5 parts. The antioxidant includes one or more of hindered phenolic antioxidant and phosphite antioxidant, specifically, the antioxidant is selected from hindered phenolic antioxidant. The amount of the antioxidant is 0-3 parts, specifically, the amount of the antioxidant is 0.3-2.6 parts, more specifically, the amount of the antioxidant is 0.8-2.0 parts.

[0035] Further, the present application also provides a preparation method of the low dielectric flat glass fiber reinforced PBT composite material, including the following steps:

[0036] According to the weight ratio, the PBT resin, the lubricant and the antioxidant are mixed to obtain a premix;

[0037] The premix is added to the main feeding port of the double screw extruder, the low dielectric flat glass fiber is added to the side feeding port of the double screw extruder, and the premix and the low dielectric flat glass fiber are mixed after being sheared by the screw, and then extruded and cooled to form a low dielectric flat glass fiber reinforced PBT composite material.

[0038] In the above preparation method, the PBT resin, lubricant and antioxidant are first mixed in a high-speed mixer to ensure uniform mixing of the raw materials and obtain a premix.

[0039] After obtaining the premix, the premix and the low dielectric flat glass fiber are extruded and cooled to form a low dielectric flat glass fiber reinforced PBT composite material; in this process, the length-diameter ratio of the double screw extruder is (30-60):1; during the extrusion process, the processing temperature of each section of the double screw extruder is 240-260℃, and the vacuum degree is 0.1MPa.

[0040] In the present application, the preparation method of the low dielectric flat glass fiber is specifically:

[0041] After the low dielectric flat glass fiber is mixed according to the component ratio, a mixture is obtained;

[0042] The mixture is melted to obtain a glass liquid;

[0043] The glass liquid is passed through a flat bushing bushing, and after being drawn, a low dielectric flat glass fiber is obtained.

[0044] In the above process, the melting temperature is 1500-1600℃; the glass liquid passes through the flat bushing bushing to facilitate the formation of flat glass fiber with a fiber cross-section aspect ratio of 2:1-5:1. The above melting and drawing process is a well-known operation means for those skilled in the art, and the present application does not make special limitations.

[0045] The present application also provides a low dielectric flat glass fiber, and the raw materials include, by mass percentage: SiO2 60-65%, Al2O3 10-19%, B2O3 16-26%, Li2O 0.6-2%, CaO 0-5%, MgO 0-8%, F2 0-2%, Fe2O3 0-0.4%, Na2O 0-0.2%, and K2O 0-0.2%.

[0046] The above low dielectric flat glass fiber of the present application has been described in detail above, and will not be repeated here.

[0047] The application provides a low-dielectric flat glass fiber reinforced PBT composite material, which is a material for simultaneously providing reinforcement, low-dielectric characteristics, low loss and anti-warping characteristics by introducing low-dielectric flat glass fiber, and does not need to add other additional additives, compared with other prior arts which respectively use 5-8 kinds of raw materials including ordinary glass fiber, glass beads, silicon powder, polytetrafluoroethylene powder and the like as raw materials for providing reinforcement, low-dielectric characteristics, low loss characteristics and anti-warping characteristics, the composite material provided by the application contains only 3-4 kinds of raw materials, and the glass fiber addition content can be selected between 20% and 50%, so that the PBT composite material has higher mechanical strength, flowability, high flowability, low warping, low dielectric constant, low dielectric loss and the like compared with other prior arts, and the process route is simple and operable.

[0048] In order to further understand the application, the low-dielectric flat glass fiber reinforced PBT composite material and the preparation method thereof provided by the application are described in detail below in combination with examples, and the protection scope of the application is not limited by the following examples.

[0049] The PBT resin in the following examples and comparative examples has a melt index of 23 g / 10 min under the test condition of 250 DEG C / 2.16 Kg.

[0050] Example 1

[0051] A low-dielectric flat glass fiber reinforced PBT composite material comprises the following raw materials:

[0052] The low-dielectric flat glass fiber reinforced PBT composite material comprises the following raw materials: 69.7 parts of polybutylene terephthalate (PBT) with a model number of BASF B4520, 0.3 parts of a phenolic antioxidant with a model number of BASF Irganox 1010, and 30 parts of low-dielectric flat glass fiber with a model number of ECS303N-3-M4 / HL of Chongqing International Fiber with a cross-sectional length-width ratio of 4:1.

[0053] A preparation method of a high-strength low-dielectric low-warping PBT composite material comprises the following steps:

[0054] Step 1, accurately weighing the mixture of the glass component proportions of the low-dielectric flat glass fiber and mixing uniformly;

[0055] Step 2, feeding the uniformly mixed mixture into a pool kiln to melt into a uniform glass liquid at a temperature of 1550 DEG C;

[0056] Step 3, drawing the glass liquid into low-dielectric flat glass fiber with a fiber cross-sectional length-width ratio of 1:4 through a bushing with a flat nozzle structure;

[0057] Step 4, the above-mentioned B4520 PBT resin, Irganox1010 antioxidant in the high-speed mixer were uniformly mixed to obtain a premix;

[0058] Step 5, the premix obtained in step 4 was transported from the main feeding port to a double screw extruder with a length-diameter ratio of 48:1, and the low dielectric flat glass fiber prepared in step 3 was added through a loss weight scale from the side feeding port, and the amount of glass fiber was controlled to be 30 parts. The premix and the sheared glass fiber were fully mixed and melted, and then extruded through a double screw extruder, cooled in a cooling water tank, and cut into 3mm pellets to obtain a low dielectric flat glass fiber reinforced PBT composite material with a glass fiber content of 30%. The processing temperature of each section of the double screw extruder was controlled at 240-260℃, and the vacuum degree was 0.1MPa.

[0059] The performance of the above-mentioned low dielectric flat glass fiber reinforced PBT composite material was detected, and the performance results are shown in Table 2.

[0060] Example 2

[0061] The preparation method of the low dielectric flat glass fiber PBT composite material was basically the same as that of Example 1, except that the low dielectric flat glass fiber composition was adjusted, specifically: SiO263%, Al2O311.1%, B2O324.25%, Li2O1.45%, Fe2O30.11%, K2O 0.04%, Na2O 0.05%; as shown in Table 1.

[0062] The performance of the above-mentioned low dielectric flat glass fiber reinforced PBT composite material was detected, and the performance results are shown in Table 2.

[0063] Example 3

[0064] The preparation method of the low dielectric flat glass fiber PBT composite material was basically the same as that of Example 1, except that the low dielectric flat glass fiber was ECS303N-3-M3 / HL with a flatness ratio of 3:1 cross-sectional length-width ratio; as shown in Table 1.

[0065] The performance of the above-mentioned low dielectric flat glass fiber reinforced PBT composite material was detected, and the performance results are shown in Table 2.

[0066] Example 4

[0067] The preparation method of the low dielectric flat glass fiber PBT composite material was basically the same as that of Example 1, except that the B4520 part was 59.7 parts, and the low dielectric flat glass fiber part was 40 parts; as shown in Table 1.

[0068] The performance of the above-mentioned low dielectric flat glass fiber reinforced PBT composite material was detected, and the performance results are shown in Table 2.

[0069] Example 5

[0070] The preparation method of the low dielectric flat glass fiber PBT composite material is basically the same as that of Example 4, except that the number of parts of B4520 is 59.2 parts, and 0.5 parts of EBS lubricant, model EB-FF, is added. The specific data are shown in Table 1.

[0071] The performance of the above low dielectric flat glass fiber reinforced PBT composite material is detected, and the performance results are shown in Table 2.

[0072] Comparative Example 1

[0073] The preparation method of the low dielectric flat glass fiber PBT composite material is basically the same as that of Example 4, except that the glass fiber is the low dielectric glass fiber ECS303N-3-K / HL of Chongqing International Composite Material Co., Ltd. with a circular cross section. The specific data are shown in Table 1.

[0074] The performance of the above low dielectric flat glass fiber reinforced PBT composite material is detected, and the performance results are shown in Table 2.

[0075] Comparative Example 2

[0076] The preparation method of the low dielectric flat glass fiber PBT composite material is basically the same as that of Example 4, except that the glass fiber is the conventional glass fiber ECS303-3-K of Chongqing International Composite Material Co., Ltd. with a circular cross section. The specific data are shown in Table 1.

[0077] The performance of the above low dielectric flat glass fiber reinforced PBT composite material is detected, and the performance results are shown in Table 2.

[0078] Comparative Example 3

[0079] The preparation method of the low dielectric flat glass fiber PBT composite material is basically the same as that of Example 4, except that the glass fiber is the conventional glass fiber ECS307AT-3-M4 of Chongqing International Composite Material Co., Ltd. with a flat cross section. The specific data are shown in Table 1.

[0080] The performance of the above low dielectric flat glass fiber reinforced PBT composite material is detected, and the performance results are shown in Table 2.

[0081] Table 1 Composition data table of low dielectric flat glass fiber PBT composite material of Examples 1-5 and Comparative Examples 1-3

[0082]

[0083]

[0084] Table 2. Properties of PBT Composites Prepared in Examples 1-5 and Comparative Examples 1-3

[0085]

[0086] The above description of the examples is merely intended to help understand the method of the present application and its core idea. It should be noted that for those skilled in the art, certain modifications and improvements can be made to the present application without departing from the principles of the present application, and these modifications and improvements also fall within the protection scope of the claims of the present application.

[0087] The above description of the disclosed examples enables those skilled in the art to make or use the application. Numerous modifications to these examples will be apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-dielectric flat glass fiber reinforced PBT composite material, comprising, by weight, the following raw materials: 50-80 parts PBT resin, 20-50 parts low dielectric flat glass fiber, 0-3 parts lubricant, 0-5 parts antioxidant; The low-dielectric flat glass fiber, by mass percentage, comprises the following raw materials: SiO2 60-65%, Al2O3 10-19%, B2O3 16-26%, Li2O 0.6-2%, CaO 0-5%, MgO 0-8%, F2 0-2%, Fe2O3 0-0.4%, Na2O 0-0.2%, and K2O 0-0.2%.

2. The PBT composite according to claim 1, characterized in that The PBT resin has a melt index of 15-45 g / 10 min under the test conditions of 250℃ / 2.16 kg.

3. The PBT composite material according to claim 1, characterized in that, The low-dielectric flat glass fiber has a dielectric constant of 4.2 to 5.0 and a dielectric loss of ≤0.005 at a test frequency of 10 GHz.

4. The PBT composite material according to claim 3, characterized in that, The aspect ratio of the low dielectric flat glass fiber is 2:1 to 5:

1.

5. The PBT composite material according to claim 1 or 3, characterized in that, The lubricant includes one or more of pentaerythritol stearate, ethylene bis-stearamide, silicone, and polytetrafluoroethylene.

6. The PBT composite material according to claim 1 or 3, characterized in that, The antioxidants include one or more of hindered phenolic antioxidants and phosphite antioxidants.

7. The PBT composite material according to claim 1 or 3, characterized in that, The content of the low dielectric flat glass fiber is 30-40 parts.

8. The method for preparing the low-dielectric flat glass fiber reinforced PBT composite material according to claim 1, comprising the following steps: PBT resin, lubricant and antioxidant are mixed according to the weight ratio to obtain a premix; The premixed material is added to the main feed port of a twin-screw extruder, and the low-dielectric flat glass fiber is added to the side feed port of the twin-screw extruder. After being sheared by the screw, the premixed material and the low-dielectric flat glass fiber are mixed, extruded, and cooled to form a low-dielectric flat glass fiber reinforced PBT composite material.

9. The preparation method according to claim 8, characterized in that, The specific method for preparing the low-dielectric flat glass fiber is as follows: After mixing according to the component ratio of low dielectric flat glass fiber, a mixture is obtained; The mixture is melted to obtain molten glass; The molten glass is drawn into low-dielectric flat glass fibers by passing it through a flat nozzle and a stencil.

10. A low-dielectric flat glass fiber, comprising, by weight percentage: SiO260~65%, Al2O310~19%, B2O316~26%, Li2O 0.6~2%, CaO 0~5%, MgO 0~8%, F20~2%, Fe2O30~0.4%, Na2O 0~0.2%, K2O 0~0.2%.

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