Light-transmitting laser-weldable glass fiber reinforced pbt material and method for producing the same

Abstract

The application relates to the technical field of engineering plastics, in particular to a glass fiber reinforced PBT material capable of being transparent and laser welded and a preparation method thereof, wherein the glass fiber reinforced PBT material comprises the following raw materials in parts by weight: PBT resin 120-140 parts, PC resin 20-40 parts, glass fiber 30-50 parts, graphene oxide grafted hyperbranched polyamide 0.01-0.02 parts, silane coupling agent 0.2-2 parts, flow agent 0.2-2 parts, lubricant 0.2-2 parts, antioxidant 0.2-1 part, ester exchange inhibitor 0.5-1.5 parts and dispersant 0.4-2 parts; the glass fiber reinforced PBT material has the advantage of improving the strength of the laser weldable PBT material.

Description

Technical Field

[0001] This application relates to the technical field of engineering plastics, and in particular to a transparent, laser-weldable glass fiber reinforced PBT material and its preparation method. Background Technology

[0002] Laser welding of plastics is a novel plastic joining technology. It utilizes a laser beam that penetrates a layer of plastic and is absorbed by the opposing layer. The heat generated by the laser melts the contact surface, thus bonding thermoplastic sheets, films, or molded parts together. After further cooling and solidification, the connection is formed. Therefore, for laser welding of plastics, the upper layer of the parts to be welded needs a certain degree of laser transmittance to ensure sufficient laser energy at the interface between the upper and lower layers.

[0003] PBT (polybutylene terephthalate) is a polyester formed by the condensation polymerization of terephthalic acid and 1,4-butanediol. It has no side chains in its molecule, a symmetrical structure, and is a highly crystalline material. Furthermore, PBT exhibits homogeneous nucleation with a fast nucleation rate and high crystallinity, meaning it contains a large number of crystals. This causes severe refraction and scattering when laser light irradiates unmodified PBT samples or templates, resulting in low laser energy transmission and failing to meet the requirements for laser welding.

[0004] Currently, the laser transmittance of PBT materials is mainly improved by controlling its crystallinity. On the one hand, nucleating agents are added to reduce the number of spherulites in PBT, thereby achieving higher transmittance of lasers at specific wavelengths. On the other hand, transparent resins, such as polycarbonate (PC) and polyethylene terephthalate (PET), are introduced to form alloys, alloying and blending PBT to reduce the proportion of non-transparent PBT in the blend and improve transmittance. However, in practical applications, it has been found that commonly used nucleating agents often generate free alkali metal ions, initiating a decomposition reaction in PBT; while the introduction of transparent resins causes transesterification reactions between PBT and alloy components, both of which degrade the mechanical properties of PBT materials. In other words, while existing PBT materials improve laser transmittance, they often lead to a decrease in their mechanical properties. Summary of the Invention

[0005] To improve the strength of laser-weldable PBT materials, this application provides a transparent, laser-weldable glass fiber reinforced PBT material and its preparation method.

[0006] In a first aspect, this application provides a light-transmitting, laser-weldable glass fiber reinforced PBT material, employing the following technical solution:

[0007] A translucent, laser-weldable glass fiber reinforced PBT material comprises the following raw materials in parts by weight: 120-140 parts PBT resin, 20-40 parts PC resin, 30-50 parts glass fiber, 0.01-0.02 parts graphene oxide-grafted hyperbranched polyamide, 0.2-2 parts silane coupling agent, 0.2-2 parts flow agent, 0.2-2 parts lubricant, 0.2-1 part antioxidant, 0.5-1.5 parts transesterification inhibitor, and 0.4-2 parts dispersant.

[0008] By adopting the above technical solution, this application improves the strength of glass fiber reinforced PBT material by adding graphene oxide grafted with hyperbranched polyamide and utilizing the excellent mechanical properties of graphene oxide. The graphene oxide is modified by hyperbranched polyamide to achieve organic modification, thereby improving its compatibility with the system and significantly reducing the interfacial tension between it and the system. Furthermore, it was found that graphene oxide grafted with hyperbranched polyamide can act as a nucleating agent, greatly reducing the spherulite particles in PBT, lowering its crystallinity, and thus improving its laser transmittance.

[0009] Preferably, the graphene oxide-grafted hyperbranched polyamide is prepared by reacting graphene oxide with terminal amino-terminated hyperbranched polyamide via an amide reaction.

[0010] By adopting the above technical solution, the carboxyl groups in the molecular structure of graphene oxide are mostly located at the edges. Utilizing these carboxyl groups for amide reaction can reduce steric hindrance and allow the reaction to proceed better. The terminal amino hyperbranched polyamide has more molecular branches and contains more amino groups, which can improve the grafting rate, thereby preparing the target product with a high grafting rate.

[0011] Preferably, the molecular weight of the terminal amino hyperbranched polyamide is 800-1000.

[0012] By adopting the above technical solution, the compatibility between graphene oxide-grafted hyperbranched polyamide and the system is related to the molecular weight of the terminal amino hyperbranched polyamide. When the molecular weight is small, the compatibility is reduced, resulting in a deterioration in the overall performance of the material. When the molecular weight is large, the steric hindrance during the reaction with graphene oxide is large, which reduces the grafting amount and thus affects the compatibility with the system. A molecular weight of 800-1000 is the preferred choice.

[0013] Preferably, the amount of graphene oxide-grafted hyperbranched polyamide added is 0.015 parts by weight.

[0014] By adopting the above technical solution, graphene oxide itself has the effect of absorbing laser light. Therefore, it is necessary to control and adjust its addition amount to optimize the overall performance of glass fiber reinforced PBT material in terms of mechanical properties and laser transmittance.

[0015] Preferably, the amount of PC resin added is 30 parts by weight.

[0016] By adopting the above technical solution, when the amount of PC added is low, the crystallization inhibition of PBT resin is low; however, when the amount added is high, it will reduce the overall strength of the material; in this system, the preferred amount added is 30 parts by weight.

[0017] Preferably, the PBT resin is a mixture of PBT resin-1 and PBT resin-2 in a mass ratio of 4:9, wherein the viscosity of PBT resin-1 is 0.8 dL / g and the viscosity of PBT resin-2 is 1.0 dL / g.

[0018] By adopting the above technical solution, the laser transmittance is better when two PBT resins with different viscosities are added together.

[0019] Preferably, the glass fiber reinforced PBT material further includes 0.4-2 parts by weight of welding powder.

[0020] By adopting the above technical solution, the welding powder can improve the welding performance of glass fiber reinforced PBT material. This application focuses on discussing the role of graphene oxide grafted hyperbranched polyamide in this system, while the role of the welding powder is common knowledge and will not be discussed in the embodiments of this application, but it is also within the scope of protection of this application.

[0021] Secondly, this application provides a method for preparing a light-transmitting, laser-weldable glass fiber reinforced PBT material, employing the following technical solution:

[0022] A method for preparing a light-transmitting, laser-weldable glass fiber reinforced PBT material, comprising the following steps:

[0023] The raw materials are stirred and mixed, then transferred to an extruder for melt blending, extrusion and granulation to obtain glass fiber reinforced PBT material; wherein the melt extrusion temperature is 240-260℃.

[0024] By adopting the above technical solution, this application improves the dispersibility of graphene oxide by modifying it, and it can be uniformly dispersed in the system without the need for other special processes; the product qualification rate obtained by the preparation method of this application can reach 98% or above, and the product uniformity is good.

[0025] In summary, this application includes at least one of the following beneficial technical effects:

[0026] 1. This application improves the strength of glass fiber reinforced PBT by adding graphene oxide grafted with hyperbranched polyamide and utilizing the excellent mechanical properties of graphene oxide. The graphene oxide is modified by hyperbranched polyamide to achieve organic modification, thereby improving its compatibility with the system and significantly reducing the interfacial tension between it and the system. Furthermore, it was found that graphene oxide grafted with hyperbranched polyamide can act as a nucleating agent, greatly reducing the spherulite particles in PBT, lowering its crystallinity, and thus improving its laser transmittance.

[0027] 2. The notched impact strength of the glass fiber reinforced PBT materials prepared in this application is all between 23.8 and 32.1 kJ / M. 2 The flexural strength of the glass fiber reinforced PBT material is between 270-298 MPa, the flexural modulus is between 10686-11203 MPa, and the tensile strength is between 227-259 MPa. Furthermore, the laser transmittance is 52.2% or higher, reaching a maximum of 63.2%. This indicates that the glass fiber reinforced PBT material prepared in this application not only has excellent laser transmittance but also exhibits excellent strength and toughness. Detailed Implementation

[0028] The following provides a more detailed description of this application in conjunction with specific details.

[0029] raw material

[0030] All raw materials used in the embodiments of this application were commercially available. Among them, the graphene oxide was approximately 1 nm thick, with 1-2 layers, an average sheet diameter of 30 μm, a specific surface area of ​​200 m² / g, and a purity >95 wt%; the glass fiber was chopped glass fiber with a diameter of 10 μm and a length of 4.5 mm; the PC resin was extrusion grade and purchased from Suzhou Yican Plastics Co., Ltd.; the silane coupling agent was KH550; the antioxidant was antioxidant 168; the flow agent was MP-20; the dispersant was polyethylene wax, of industrial grade; the lubricant was PETS, manufactured by Guangzhou Shanshan New Material Technology Co., Ltd.; and the transesterification inhibitor was triphenyl phosphate.

[0031] Example

[0032] Example 1

[0033] A transparent, laser-weldable glass fiber reinforced PBT material, the preparation method of which is as follows:

[0034] S1. Preparation of graphene oxide-grafted hyperbranched polyamide

[0035] 0.2 g of graphene oxide was added to 100 mL of DMF and ultrasonically dispersed. Then, 0.045 g of EDC, 0.033 g of HOBt, and 0.035 g of triethylamine were added. After stirring for 30 min, 0.08 g of terminal amino hyperbranched polyamide was added, and the mixture was stirred for 2 h. After centrifugation, the precipitate was filtered and washed with DMF and ethanol, respectively, and then dried to obtain graphene oxide-grafted hyperbranched polyamide. The terminal amino hyperbranched polyamide was designated as HyPer N101 with a molecular weight of 350-370.

[0036] S2. 130 kg of PBT resin, 30 kg of PC resin, 40 kg of glass fiber, 0.01 kg of graphene oxide-grafted hyperbranched polyamide, 1 kg of silane coupling agent, 1 kg of flow agent, 1 kg of lubricant, 0.8 kg of antioxidant, 1 kg of transesterification inhibitor, and 1 kg of dispersant are added to a high-speed mixing tank and mixed at a stirring speed of 600 r / min. Then, the mixture is transferred to a twin-screw extruder for melt blending, extrusion granulation, and glass fiber reinforced PBT material. The melt extrusion temperature is 250℃, and the screw speed is 700 r / min. The PBT resin is a mixture of PBT resin-1 and PBT resin-2 in a mass ratio of 4:9. The viscosity of PBT resin-1 is 0.8 dL / g, and the viscosity of PBT resin-2 is 1.0 dL / g.

[0037] Example 2

[0038] A translucent, laser-weldable glass fiber reinforced PBT material differs from Example 1 in that the terminal amino hyperbranched polyamide in its S1 is of type HyPer N102 with a molecular weight of 800-1000 and an addition amount of 0.2g. The remaining steps are the same as in Example 1.

[0039] Example 3

[0040] A translucent, laser-weldable glass fiber reinforced PBT material differs from Example 1 in that the type of its S1 terminal amino hyperbranched polyamide is HyPer N103, the molecular weight is 1900-2200, and the addition amount is 0.46g. The remaining steps are the same as in Example 1.

[0041] Example 4

[0042] A transparent, laser-weldable glass fiber reinforced PBT material differs from Example 2 in that the amount of graphene oxide grafted hyperbranched polyamide added in S2 is 0.015 kg, while the remaining steps are the same as in Example 2.

[0043] Example 5

[0044] A transparent, laser-weldable glass fiber reinforced PBT material differs from Example 2 in that the amount of graphene oxide-grafted hyperbranched polyamide added in S2 is 0.02 kg, while the remaining steps are the same as in Example 2.

[0045] Example 6

[0046] A light-transmitting, laser-weldable glass fiber reinforced PBT material differs from Example 4 in that the amount of PC resin added in S2 is 20 kg, and the amount of PBT resin added is 140 kg, while the remaining steps are the same as in Example 4.

[0047] Example 7

[0048] A light-transmitting, laser-weldable glass fiber reinforced PBT material differs from Example 4 in that the amount of PC resin added in S2 is 40 kg and the amount of PBT resin added is 120 kg, while the remaining steps are the same as in Example 4.

[0049] Example 8

[0050] A light-transmitting, laser-weldable glass fiber reinforced PBT material differs from Example 4 in that the PBT resin in S2 is PBT resin-1, while the remaining steps are the same as in Example 4.

[0051] Example 9

[0052] A light-transmitting, laser-weldable glass fiber reinforced PBT material differs from Example 4 in that the PBT resin in S2 is PBT resin-2, while the remaining steps are the same as in Example 4.

[0053] Comparative Example

[0054] Comparative Example 1

[0055] A transparent, laser-weldable glass fiber reinforced PBT material differs from Example 4 in that graphene oxide grafted hyperbranched polyamide is not added in S2, while the remaining steps are the same as in Example 4.

[0056] Comparative Example 2

[0057] A transparent, laser-weldable glass fiber reinforced PBT material differs from Example 4 in that the graphene oxide grafted hyperbranched polyamide added in S2 is replaced with an equal mass of graphene oxide, while the remaining steps are the same as in Example 4.

[0058] Comparative Example 3

[0059] A translucent, laser-weldable glass fiber reinforced PBT material differs from Example 4 in that the end-carboxyl hyperbranched polyamide added in S1 is replaced with an equal mass of end-carboxyl poly(lactic-co-glycolic acid), the average molecular weight of which is 1000, and it was customized by Jinan Daigang Bioengineering Co., Ltd. The remaining steps are the same as in Example 4.

[0060] Performance testing

[0061] Detection methods / test methods

[0062] Glass fiber reinforced PBT materials were prepared according to the preparation methods of Examples 1-9 and Comparative Examples 1-3, and then tested according to the following testing methods. The test results are shown in Table 1.

[0063] Notched impact strength: Tested according to the test method in GB / T 1843-2008;

[0064] Bending strength: Tested according to the test method in GB / T 9341-2008;

[0065] Flexural modulus: Tested according to the test method in GB / T 9341-2008;

[0066] Tensile strength: Tested according to the test method in GB / T 1040.1-2006;

[0067] Laser transmittance: The infrared transmittance at 980nm was tested using a Guangzhou Yuke T-1000 transmittance tester. The thickness of the color plate made of glass fiber reinforced PBT material was 2mm.

[0068] Ethylene glycol resistance time: No cracks were observed after immersing the glass fiber reinforced PBT materials of Examples 1-9 in an ethylene glycol solution for 72 hours and 240 hours.

[0069] Density: Tested according to the method in GB / T 1033.1-2008, the densities of the glass fiber reinforced PBT materials in Examples 1-9 are all between 1.43 and 1.49 g / cm³. 3 between.

[0070] Table 1. Detection results of Examples 1-9 and Comparative Examples 1-3

[0071]

[0072] As can be seen from Examples 1-9, Comparative Examples 1-3, and the test data in Table 1, the notched impact strength of the glass fiber reinforced PBT material prepared in this application is all between 23.8 and 32.1 kJ / M. 2The flexural strength of the glass fiber reinforced PBT material is between 270-298 MPa, the flexural modulus is between 10686-11203 MPa, and the tensile strength is between 227-259 MPa. Furthermore, the laser transmittance is 52.2% or higher, reaching a maximum of 63.2%. This indicates that the glass fiber reinforced PBT material prepared in this application not only has excellent laser transmittance but also exhibits excellent strength and toughness.

[0073] This application improves the strength of glass fiber reinforced PBT by adding graphene oxide grafted with hyperbranched polyamide, leveraging the excellent mechanical properties of graphene oxide. The graphene oxide is modified with hyperbranched polyamide to achieve organic modification, thereby improving its compatibility with the system and significantly reducing the interfacial tension. Furthermore, it was found that graphene oxide grafted with hyperbranched polyamide acts as a nucleating agent, greatly reducing the number of spherulites in PBT, lowering its crystallinity, and thus improving its laser transmittance. This is verified by the test data from Example 1 and Comparative Examples 1-2. The compatibility between graphene oxide-grafted hyperbranched polyamide and the system is related to the molecular weight of the terminal amino hyperbranched polyamide. When the molecular weight is small, the compatibility is reduced, resulting in a deterioration in the overall performance of the material. When the molecular weight is large, the steric hindrance during the reaction with graphene oxide is large, which reduces the grafting amount and thus affects the compatibility with the system. Through Examples 1-3, a molecular weight of 800-1000 is the preferred choice.

[0074] However, graphene oxide itself absorbs laser light; therefore, its addition amount needs to be controlled and adjusted to optimize the overall performance of the glass fiber reinforced PBT material in terms of both mechanical properties and laser transmittance. This can be verified by combining the test data from Examples 2 and 4-5.

[0075] The test data from Examples 4 and 6-7 show that when the amount of PC added is low, the inhibition of PBT resin crystallization is low; however, when the amount added is high, it will reduce the overall strength of the material; in this system, the preferred amount added is 30 kg.

[0076] The test data from Examples 4 and 8-9 show that when two PBT resins of different viscosities are added together in this application, the laser transmittance is better.

[0077] The test data from Example 4 and Comparative Example 3 show that, ignoring the differences in polymer reactants, when the linear polymer modifies graphene oxide, the modified graphene oxide is less compatible with the system than the graphene oxide modified by the hyperbranched polymer. It is speculated that this is because the hyperbranched polymer itself has lower viscosity, and its terminal amino groups can form hydrogen bonds with the oxygen and hydrogen atoms in the system, allowing the polymer chains in the system to cover more of the graphene oxide, thereby reducing the surface tension between the polymer and the system and enabling it to act as a nucleating agent. Modification with linear polymer molecules does not achieve this effect.

[0078] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A light-transmitting, laser-weldable glass fiber reinforced PBT material, characterized in that: It comprises the following raw materials in parts by weight: 120-140 parts PBT resin, 20-40 parts PC resin, 30-50 parts glass fiber, 0.01-0.02 parts graphene oxide-grafted hyperbranched polyamide, 0.2-2 parts silane coupling agent, 0.2-2 parts flow agent, 0.2-2 parts lubricant, 0.2-1 part antioxidant, 0.5-1.5 parts transesterification inhibitor, and 0.4-2 parts dispersant; The graphene oxide-grafted hyperbranched polyamide is prepared by reacting graphene oxide with amino-terminated hyperbranched polyamide via an amide reaction.

2. The light-transmitting, laser-weldable glass fiber reinforced PBT material according to claim 1, characterized in that: The molecular weight of the terminal amino hyperbranched polyamide is 800-1000.

3. The light-transmitting, laser-weldable glass fiber reinforced PBT material according to claim 1, characterized in that: The amount of graphene oxide-grafted hyperbranched polyamide added is 0.015 parts by weight.

4. The light-transmitting, laser-weldable glass fiber reinforced PBT material according to claim 1, characterized in that: The amount of PC resin added is 30 parts by weight.

5. The light-transmitting, laser-weldable glass fiber reinforced PBT material according to claim 1, characterized in that: The PBT resin is a mixture of PBT resin-1 and PBT resin-2 in a mass ratio of 4:9, wherein the viscosity of PBT resin-1 is 0.8 dL / g and the viscosity of PBT resin-2 is 1.0 dL / g.

6. The transparent, laser-weldable glass fiber reinforced PBT material according to claim 1, characterized in that: The glass fiber reinforced PBT material also includes 0.4-2 parts by weight of welding powder.

7. A method for preparing a transparent, laser-weldable glass fiber reinforced PBT material according to any one of claims 1-6, characterized in that: It includes the following steps: The raw materials are stirred and mixed, then transferred to an extruder for melt blending, extrusion and granulation to obtain glass fiber reinforced PBT material; wherein the melt extrusion temperature is 240-260℃.

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