Hydrolysis-resistant glass fiber reinforced PBT composite material and preparation method thereof

Abstract

The invention relates to the technical field of automobile, lighting and electronic and electrical plastics, and discloses a hydrolysis-resistant glass fiber reinforced PBT composite material and a preparation method thereof.The preparation method comprises the following steps that PBT resin is pretreated, specifically, the PBT resin is put into a homogenizing tank to be dried, the drying temperature is 80-90 DEG C, the drying time is 2-3 hours, and then the PBT resin is taken out; the preparation method comprises the following steps: drying PBT resin, then absorbing the dried PBT resin into a main material scale by adopting a vacuum material absorbing process, pretreating glass fibers, selecting a hydrolysis-resistant agent of a specific type, optimizing the adding proportion of the hydrolysis-resistant agent and a mixing process, so that the hydrolysis-resistant agent can accurately react with ester bonds which are easy to hydrolyze in PBT resin molecules to form effective protection; erosion of water to ester bonds in a high-temperature and high-humidity environment can be inhibited in real time and for a long time, the mechanical strength and dimensional stability of a composite material product in long-term use are guaranteed, and the service life of parts in a severe environment is prolonged.

Description

Technical Field

[0001] This invention relates to the fields of automotive, lighting, and electronic and electrical plastics technology, specifically to a hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method. Background Technology

[0002] PBT, short for polybutylene terephthalate, is a translucent and opaque crystalline thermoplastic polyester resin. It features high temperature resistance, moisture resistance, oil resistance, good electrical insulation, chemical corrosion resistance, fast molding, easy molding, and low moisture absorption. In applications, PBT has been widely used in many fields such as electronics, automobiles, machinery, and optical fiber sheathing.

[0003] Currently, due to the presence of easily hydrolyzed ester bonds in the molecular structure of PBT resin, moisture can corrode the material and cause ester bond breakage in high-temperature and high-humidity environments. This makes it impossible to maintain the mechanical strength and dimensional stability of glass fiber reinforced PBT composite products in the long term. When the material undergoes severe hydrolysis, it can cause premature failure of components, compromising the reliability of the final product. Furthermore, when reinforcing PBT with glass fiber, poor interfacial compatibility between the glass fiber and the PBT matrix can result in weak interfacial bonding. These weak interfaces become rapid channels for moisture penetration, further accelerating the hydrolysis process. Conventional methods of adding hydrolysis-resistant agents to improve the material's hydrolysis resistance cannot achieve uniform dispersion of the agent in the matrix or precise interaction with the ester bonds. This can lead to insufficient localized hydrolysis resistance and affect other material properties, further limiting the application range and service life of glass fiber reinforced PBT composites in harsh environments.

[0004] Therefore, a hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method are proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method, solving the problem of premature component failure and inability to guarantee the reliability of the final product mentioned in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method, comprising the following steps: Step 1: PBT resin pretreatment. PBT resin is put into a homogenization tank for drying at a temperature of 80-90℃ for 2-3 hours. Then, the dried PBT resin is sucked into the main material weighing tank using a vacuum feeding process. Step 2: Glass fiber pretreatment. Put the glass fiber into the drying oven for drying at a temperature of 85-95℃ for 2-3 hours. Then, manually feed it into the side-feeding scale. Step 3: Additive mixing. The hydrolysis resistant agent, antioxidant and lubricant are mixed evenly in proportion by a pulverizer to obtain mixed additives, and then put into a powder weigher. Step 4: Add toughening agent. Add the toughening agent to the auxiliary material weigher. Step 5: Melt blending. Set the proportions of each loss-in-weight ratio, and melt blend the raw materials from steps 1 to 4 in a twin-screw extruder. The melt blending temperature is 230-270℃, and the screw speed is 500-700 rpm. After extrusion granulation, hydrolysis-resistant glass fiber reinforced PBT composite material particles are obtained.

[0007] Preferably, in step one, the drying process is carried out in a homogenization tank, the volume of which is 15-25m³. 3 The drying temperature is 80-90℃, the drying time is 2-3 hours, the vacuum degree of the vacuum suction process is -0.05 to -0.1MPa, and the suction speed is 50-100kg / min.

[0008] Preferably, in step two, the glass fiber is a polyester-specific hydrolysis-resistant glass fiber with a fiber diameter of 13±1 micrometers and a fiber length of 3-4.5 mm. The drying process is carried out in a drying oven at a temperature of 85-95℃ for 2-3 hours. During the manual feeding process, a moisture-proof container is used to transport the glass fiber to the side feeder to avoid secondary moisture absorption.

[0009] Preferably, in step three, the mixing speed of the pulverizer is 100-300 r / min, the mixing time is 5-15 minutes, the mixing order of the hydrolysis resistant agent, antioxidant and lubricant is to add the hydrolysis resistant agent first, then add the antioxidant, and finally add the lubricant. During the mixing process, the ambient humidity is kept below 30%, and the feeding accuracy of the mixed additives in the powder weigher is ±0.1 parts.

[0010] Preferably, in step five, the twin-screw extruder has a screw length-to-diameter ratio of 36:1 to 40:1, and the melt mixing temperature is controlled in zones, with the temperature from the feed inlet to the die set at 230℃, 250℃, 260℃, and 270℃. The screw speed is 500-700 rpm. After extrusion granulation, a devolatilization process is performed, with a devolatilization temperature of 70-90℃ and a devolatilization time of 1-3 hours. The devolatilization equipment is a vacuum devolatilization tank, and the vacuum degree is maintained at -0.08 to -0.1 MPa.

[0011] Preferably, it is made from the following raw materials in parts by weight: 65-70 parts PBT resin, 2-4 parts toughening agent, 28-32 parts glass fiber, 0.5-1.5 parts hydrolysis resistant agent, 0.2-0.4 parts lubricant, and 0.5-0.7 parts antioxidant.

[0012] Preferably, the PBT resin is polybutylene terephthalate resin with an intrinsic viscosity of 0.95-1.05 dL / g and a terminal carboxyl group content of less than 10 mol / t. The PBT resin is homogenized before processing to ensure batch stability.

[0013] Preferably, the toughening agent is selected from one or more of MBS, EBA-GMA or EMA-GMA, and the toughening agent is added by direct feeding or premixing into masterbatch, with a particle size distribution of 50-200 micrometers.

[0014] Preferably, the glass fiber is alkali-free glass fiber, and its surface is treated with a silane coupling agent with a content of 0.1-0.5%. The uniformity of the dispersion of the glass fiber in the composite material is observed under a microscope, and no agglomeration is observed.

[0015] Preferably, the hydrolysis-resistant agent is selected from at least one of monomeric carbodiimide, polymeric carbodiimide, isocyanate or oxazoline compounds; the lubricant is one or more of vinyl bis-stearamide, pentaerythritol stearate or silicone; and the antioxidant is a composite system of hindered phenolic antioxidant and phosphite antioxidant, wherein the hindered phenolic antioxidant is selected from antioxidant 1010, antioxidant 1076 or antioxidant 1098, and the phosphite antioxidant is selected from antioxidant 168 or antioxidant 626.

[0016] Compared with the prior art, the present invention provides a hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method, which has the following beneficial effects: 1. In this invention, when preparing hydrolysis-resistant glass fiber reinforced PBT composite materials, by selecting a specific type of hydrolysis-resistant agent and optimizing its addition ratio and mixing process, the hydrolysis-resistant agent can precisely interact with the easily hydrolyzed ester bonds in PBT resin molecules to form effective protection. This can inhibit the erosion of ester bonds by moisture under high temperature and high humidity conditions in real time and for a long time, ensuring the mechanical strength and dimensional stability of composite material products during long-term use, and extending the service life of parts in harsh environments.

[0017] 2. In this invention, when preparing hydrolysis-resistant glass fiber reinforced PBT composite material, the interfacial bonding force between the glass fiber and the PBT resin matrix is ​​enhanced by using glass fibers with specific surface treatment and in combination with toughening agents. This makes the two-phase interface firmly bonded, effectively reducing the risk of the interface becoming a water penetration channel, reducing the material's early hydrolysis failure due to interface problems, and thus improving the overall structural integrity and hydrolysis resistance reliability of the composite material.

[0018] 3. In this invention, during the preparation of hydrolysis-resistant glass fiber reinforced PBT composite material, strict pretreatment of PBT resin, glass fiber, and various additives is carried out to control moisture content. Furthermore, the melt blending process parameters of the twin-screw extruder are optimized to ensure highly uniform dispersion of hydrolysis-resistant agents, antioxidants, and lubricants in the PBT matrix. This avoids insufficient performance in localized areas, resulting in a synergistic improvement in the hydrolysis resistance, mechanical properties, and processing stability of the composite material. This further ensures the consistency and reliability of the final product's performance. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method, comprising the following steps: Step 1: PBT resin pretreatment. PBT resin is put into a homogenization tank for drying at 80°C for 2 hours. Then, the dried PBT resin is sucked into the main material weighing tank using a vacuum feeding process. Step 2: Glass fiber pretreatment. The glass fiber is put into the drying box for drying at 85℃ for 2 hours. Then it is manually fed into the side feeder. Step 3: Additive mixing. The hydrolysis resistant agent, antioxidant and lubricant are mixed evenly in proportion by a pulverizer to obtain mixed additives, and then put into a powder weigher. Step 4: Add toughening agent. Add the toughening agent to the auxiliary material weigher. Step 5: Melt blending. Set the proportions of each loss-in-weight ratio, and melt blend the raw materials from Step 1 to Step 4 in a twin-screw extruder. The melt blending temperature is 230℃-270℃, the screw speed is 500 rpm, and after extrusion granulation, hydrolysis-resistant glass fiber reinforced PBT composite material particles are obtained. In step one, the drying process is carried out in a homogenization tank with a volume of 15m³.3 The drying temperature is 80℃, the drying time is 2 hours, the vacuum degree of the vacuum feeding process is -0.08MPa, and the feeding speed is 50kg / min; In step two, the glass fiber is a special hydrolysis-resistant polyester glass fiber with a fiber diameter of 13 micrometers and a fiber length of 3mm. The drying process is carried out in a drying box at a drying temperature of 85℃ for 2 hours. During the manual feeding process, a moisture-proof container is used to transport the glass fiber to the side feeder to avoid secondary moisture absorption. In step three, the mixing speed of the pulverizer is 100 r / min, the mixing time is 5 minutes, and the mixing order of the hydrolysis resistant agent, antioxidant and lubricant is to add the hydrolysis resistant agent first, then the antioxidant, and finally the lubricant. During the mixing process, the ambient humidity is kept below 30%, and the feeding accuracy of the mixed additives in the powder weigher is ±0.1 parts. In step five, the twin-screw extruder has a screw length-to-diameter ratio of 36:1, and the melt mixing temperature is controlled in zones. The temperature from the feed inlet to the die is set to 230℃, 250℃, 260℃, and 270℃. The screw speed is 500 rpm. After extrusion granulation, a devolatilization process is also carried out. The devolatilization temperature is 80℃, the devolatilization time is 1 hour, and the devolatilization equipment is a vacuum devolatilization tank with the vacuum degree maintained at -0.08MPa. It is made from the following raw materials in parts by weight: 65 parts PBT resin, 2 parts toughening agent, 28 parts glass fiber, 0.5 parts hydrolysis resistant agent, 0.2 parts lubricant, and 0.5 parts antioxidant; PBT resin is polybutylene terephthalate resin with an intrinsic viscosity of 0.95 dL / g and a terminal carboxyl group content of less than 10 mol / t. PBT resin undergoes homogenization treatment before processing to ensure batch stability. The toughening agent is selected from one or more of MBS, EBA-GMA or EMA-GMA. The toughening agent is added by direct feeding or premixing into masterbatch, and its particle size distribution is 50 micrometers. The glass fiber is alkali-free glass fiber, and its surface is treated with silane coupling agent with a content of 0.1%. The uniformity of the glass fiber dispersion in the composite material was observed under a microscope, and no agglomeration was observed. The hydrolysis resistant agent is selected from at least one of monomeric carbodiimide, polymeric carbodiimide, isocyanate or oxazoline compounds; the lubricant is one or more of vinyl bis-stearamide, pentaerythritol stearate or silicone; and the antioxidant is a composite system of hindered phenolic antioxidant and phosphite antioxidant, wherein the hindered phenolic antioxidant is selected from antioxidant 1010, antioxidant 1076 or antioxidant 1098, and the phosphite antioxidant is selected from antioxidant 168 or antioxidant 626.

[0021] Example 2: A hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method, comprising the following steps: Step 1: PBT resin pretreatment. PBT resin is put into a homogenization tank for drying at 85°C for 2.5 hours. Then, the dried PBT resin is sucked into the main material weighing tank using a vacuum feeding process. Step 2: Glass fiber pretreatment. The glass fiber is put into the drying oven for drying at 90℃ for 2.5 hours. Then it is manually fed into the side feeder. Step 3: Additive mixing. The hydrolysis resistant agent, antioxidant and lubricant are mixed evenly in proportion by a pulverizer to obtain mixed additives, and then put into a powder weigher. Step 4: Add toughening agent. Add the toughening agent to the auxiliary material weigher. Step 5: Melt blending. Set the proportions of each loss-in-weight ratio, and melt blend the raw materials from Step 1 to Step 4 in a twin-screw extruder. The melt blending temperature is 250℃ and the screw speed is 600 rpm. After extrusion granulation, hydrolysis-resistant glass fiber reinforced PBT composite material particles are obtained. In step one, the drying process is carried out in a homogenization tank with a volume of 20m³. 3 The drying temperature is 85℃, the drying time is 2.5 hours, the vacuum degree of the vacuum feeding process is -0.07MPa, and the feeding speed is 70kg / min; In step two, the glass fiber is a special hydrolysis-resistant polyester glass fiber with a fiber diameter of 15 micrometers and a fiber length of 4 mm. The drying process is carried out in a drying box at a drying temperature of 90℃ for 2.5 hours. During the manual feeding process, a moisture-proof container is used to transport the glass fiber to the side feeder to avoid secondary moisture absorption. In step three, the mixing speed of the pulverizer is 200 r / min, the mixing time is 10 minutes, and the mixing order of the hydrolysis resistant agent, antioxidant and lubricant is to add the hydrolysis resistant agent first, then the antioxidant, and finally the lubricant. During the mixing process, the ambient humidity is kept below 30%, and the feeding accuracy of the mixed additives in the powder weigher is ±0.1 parts. In step five, the twin-screw extruder has a screw length-to-diameter ratio of 36:1, and the melt mixing temperature is controlled in zones. The temperature from the feed inlet to the die is set to 230℃, 240℃, 250℃, and 260℃, and the screw speed is 600 rpm. After extrusion and granulation, a devolatilization process is also carried out. The devolatilization temperature is 80℃, the devolatilization time is 2 hours, and the devolatilization equipment is a vacuum devolatilization tank with the vacuum degree maintained at -0.09MPa. It is made from the following raw materials in parts by weight: 67 parts PBT resin, 3 parts toughening agent, 30 parts glass fiber, 1.0 part hydrolysis resistant agent, 0.3 parts lubricant, and 0.6 parts antioxidant; PBT resin is polybutylene terephthalate resin with an intrinsic viscosity of 0.99 dL / g and a terminal carboxyl group content of less than 10 mol / t. PBT resin undergoes homogenization treatment before processing to ensure batch stability. The toughening agent is selected from one or more of MBS, EBA-GMA or EMA-GMA. The toughening agent is added by direct feeding or premixing into masterbatch, and its particle size distribution is 50-200 micrometers. The glass fiber is alkali-free glass fiber, and its surface is treated with silane coupling agent with a content of 0.3%. The uniformity of the glass fiber dispersion in the composite material was observed under a microscope, and no agglomeration was observed. The hydrolysis resistant agent is selected from at least one of monomeric carbodiimide, polymeric carbodiimide, isocyanate or oxazoline compounds; the lubricant is one or more of vinyl bis-stearamide, pentaerythritol stearate or silicone; and the antioxidant is a composite system of hindered phenolic antioxidant and phosphite antioxidant, wherein the hindered phenolic antioxidant is selected from antioxidant 1010, antioxidant 1076 or antioxidant 1098, and the phosphite antioxidant is selected from antioxidant 168 or antioxidant 626.

[0022] Example 3: A hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method, comprising the following steps: Step 1: PBT resin pretreatment. PBT resin is put into a homogenization tank for drying at 90°C for 3 hours. Then, the dried PBT resin is sucked into the main material weighing tank using a vacuum feeding process. Step 2: Glass fiber pretreatment. The glass fiber is put into the drying box for drying at 95℃ for 3 hours. Then it is manually fed into the side feeder. Step 3: Additive mixing. The hydrolysis resistant agent, antioxidant and lubricant are mixed evenly in proportion by a pulverizer to obtain mixed additives, and then put into a powder weigher. Step 4: Add toughening agent. Add the toughening agent to the auxiliary material weigher. Step 5: Melt blending. Set the proportions of each loss-in-weight ratio, and melt blend the raw materials from Step 1 to Step 4 in a twin-screw extruder. The melt blending temperature is 260℃ and the screw speed is 700 rpm. After extrusion granulation, hydrolysis-resistant glass fiber reinforced PBT composite material particles are obtained. In step one, the drying process is carried out in a homogenization tank with a volume of 25m³. 3 The drying temperature is 90℃, the drying time is 3 hours, the vacuum degree of the vacuum feeding process is -0.1MPa, and the feeding speed is 100kg / min; In step two, the glass fiber is a special hydrolysis-resistant polyester glass fiber with a fiber diameter of 20 micrometers and a fiber length of 5 mm. The drying process is carried out in a drying box at a drying temperature of 95°C for 3 hours. During the manual feeding process, the glass fiber is transported to the side feeder using a moisture-proof container to avoid secondary moisture absorption. In step three, the mixing speed of the pulverizer is 300 r / min, the mixing time is 15 minutes, and the mixing order of the hydrolysis resistant agent, antioxidant and lubricant is to add the hydrolysis resistant agent first, then the antioxidant, and finally the lubricant. During the mixing process, the ambient humidity is kept below 30%, and the feeding accuracy of the mixed additives in the powder weigher is ±0.1 parts. In step five, the twin-screw extruder has a screw length-to-diameter ratio of 40:1, and the melt mixing temperature is controlled in zones. The temperature from the feed inlet to the die is set to 230℃, 240℃, 250℃, and 260℃, and the screw speed is 700 rpm. After extrusion and granulation, a devolatilization process is also carried out. The devolatilization temperature is 90℃, the devolatilization time is 3 hours, and the devolatilization equipment is a vacuum devolatilization tank with the vacuum degree maintained at -0.1MPa. It is made from the following raw materials in parts by weight: 70 parts PBT resin, 4 parts toughening agent, 32 parts glass fiber, 1.5 parts hydrolysis resistant agent, 0.4 parts lubricant, and 0.7 parts antioxidant; PBT resin is polybutylene terephthalate resin with an intrinsic viscosity of 1.05 dL / g and a terminal carboxyl group content of less than 10 mol / t. PBT resin undergoes homogenization treatment before processing to ensure batch stability. The toughening agent is selected from one or more of MBS, EBA-GMA or EMA-GMA. The toughening agent is added by direct feeding or premixing into masterbatch, and its particle size distribution is 200 micrometers. The glass fiber is alkali-free glass fiber, and its surface is treated with silane coupling agent with a content of 0.5%. The uniformity of the glass fiber dispersion in the composite material was observed under a microscope, and no agglomeration was observed. The hydrolysis resistant agent is selected from at least one of monomeric carbodiimide, polymeric carbodiimide, isocyanate or oxazoline compounds; the lubricant is one or more of vinyl bis-stearamide, pentaerythritol stearate or silicone; and the antioxidant is a composite system of hindered phenolic antioxidant and phosphite antioxidant, wherein the hindered phenolic antioxidant is selected from antioxidant 1010, antioxidant 1076 or antioxidant 1098, and the phosphite antioxidant is selected from antioxidant 168 or antioxidant 626.

[0023] Comparative Example 1: The difference between this comparative example and Example 1 is that no hydrolysis-resistant agent was added during the preparation process of this comparative example.

[0024] Comparative Example 2: The difference between this comparative example and Example 2 is that the glass fiber was not dried during the preparation process in this comparative example.

[0025] Comparative Example 3 differs from Example 3 in that no toughening agent was added during the preparation process of this comparative example.

[0026] Comparative Example 4 differs from Example 3 in that: in the preparation process, a twin-screw extruder was not used for melt blending in this comparative example, but a high-speed mixer was used for mixing and then directly injection molding.

[0027] The hydrolysis-resistant glass fiber reinforced PBT composites prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The test items and test methods are as follows: For the hydrolysis resistance test, the sample is placed in a pressure vessel and treated for the same number of hours under the same temperature and relative humidity conditions. Then, it is taken out and its tensile strength retention rate is measured. Tensile strength testing was performed using a universal testing machine. Bending strength testing was performed using a universal testing machine. Impact strength testing was performed using a cantilever beam impact testing machine. For the water absorption test, the sample was soaked in distilled water for 24 hours at room temperature of 25°C. After drying and weighing, the sample was soaked in water again, removed and the surface moisture was wiped off. The percentage increase in mass was then calculated.

[0028] The test data of the hydrolysis-resistant glass fiber reinforced PBT composites prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below: Group Tensile strength retention rate (%) Tensile strength (MPa) Bending strength (MPa) Impact strength (kJ / m²) Water absorption rate (%) Example 1 86.5 135 195 9.5 0.22 Example 2 88.2 138 201 10.1 0.20 Example 3 87.0 136 198 9.8 0.21 Comparative Example 1 61.3 125 185 8.9 0.35 Comparative Example 2 75.4 128 178 8.0 0.31 Comparative Example 3 82.1 118 165 6.5 0.28 Comparative Example 4 70.8 122 172 7.2 0.33 By comparing and analyzing the data in the table, it can be seen that the hydrolysis-resistant glass fiber reinforced PBT composite materials prepared using the processes in Examples 1-3 have significantly better performance than the materials prepared using the processes in Comparative Examples 1-4. This indicates that by selecting specific types of hydrolysis-resistant agents and optimizing their addition ratio and mixing process during the preparation of hydrolysis-resistant glass fiber reinforced PBT composite materials, the hydrolysis-resistant agents can precisely interact with the easily hydrolyzed ester bonds in PBT resin molecules, forming an effective protection. This can effectively and continuously inhibit the erosion of ester bonds by moisture under high temperature and high humidity environments, ensuring the mechanical strength and dimensional stability of composite products during long-term use, and extending the service life of components in harsh environments. Furthermore, the use of glass fibers with specific surface treatments and the synergistic effect of toughening agents in the preparation of hydrolysis-resistant glass fiber reinforced PBT composite materials... The application of this technology enhances the interfacial bonding between glass fiber and the PBT resin matrix, resulting in a strong bond between the two phases. This effectively reduces the risk of moisture penetration due to weak interfaces, lowers the risk of early hydrolysis failure caused by interfacial issues, and improves the overall structural integrity and hydrolysis resistance of the composite material. In preparing hydrolysis-resistant glass fiber reinforced PBT composites, strict pretreatment of PBT resin, glass fiber, and various additives is performed to control moisture content. Furthermore, the melt blending process parameters of the twin-screw extruder are optimized to ensure highly uniform dispersion of hydrolysis-resistant agents, antioxidants, and lubricants in the PBT matrix. This avoids insufficient performance in localized areas, resulting in a synergistic improvement in the hydrolysis resistance, mechanical properties, and processing stability of the composite material, further guaranteeing the consistency and reliability of the final product performance.

[0029] By comparing and analyzing the relevant data in the table, it can be seen that the hydrolysis-resistant glass fiber reinforced PBT composite material prepared by the molding process of the present invention has excellent hydrolysis resistance, good mechanical properties and dimensional stability. This shows that the hydrolysis-resistant glass fiber reinforced PBT composite material and its preparation method provided by the present invention have superior comprehensive performance.

[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0031] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for the production of a hydrolysis resistant glass fiber reinforced PBT composite material, characterized in that, It comprises the following steps: Step one: PBT resin pretreatment, put PBT resin into homogenizing tank for drying treatment, drying temperature is 80-90℃, drying time is 2-3 hours, then use vacuum suction process to suck the dried PBT resin into the main material scale; Step two: glass fiber pretreatment, put glass fiber into the drying box for drying treatment, drying temperature is 85-95℃, drying time is 2-3 hours, then manually put into the side feeding scale; Step three: additive mixing, mix hydrolysis resistant agent, antioxidant and lubricant in proportion through powder mixer to get mixed additives, then put into the powder scale; Step four: toughening agent feeding, put toughening agent into the auxiliary scale; Step five: melt blending, set the proportion of each weight loss scale, melt blend the raw materials of step one to step four in the double screw extruder, melt mixing temperature is 230-270℃, screw speed is 500-700r / min, after extruding and granulating, get hydrolysis resistant glass fiber reinforced PBT composite material particles.

2. The method for preparing a hydrolysis-resistant glass fiber reinforced PBT composite material according to claim 1, characterized in that, The drying treatment in step one is carried out in a homogenizing tank, the volume of the homogenizing tank is 15-25 m 3 The drying temperature is 80-90℃, the drying time is 2-3 hours, the vacuum degree of the vacuum suction process is -0.05 to -0.1 MPa, and the suction speed is 50-100 kg / min.

3. The method for preparing a hydrolysis-resistant glass fiber reinforced PBT composite material according to claim 1, characterized in that, In the step two, the glass fiber is polyester special hydrolysis resistant glass fiber, fiber diameter is 13±1 microns, fiber length is 3-4.5mm, the drying treatment is carried out in the drying box, drying temperature is 85-95℃, drying time is 2-3 hours, in the process of manual feeding, use moisture-proof container to transport glass fiber to the side feeding scale to avoid secondary moisture absorption.

4. The method for preparing a hydrolysis-resistant glass fiber reinforced PBT composite material according to claim 1, characterized in that, In the step three, the mixing speed of the powder mixer is 100-300r / min, mixing time is 5-15 minutes, the mixing order of the hydrolysis resistant agent, antioxidant and lubricant is first add hydrolysis resistant agent, then add antioxidant, finally add lubricant, keep the environment humidity below 30% during mixing, the feeding accuracy of the mixed additives in the powder scale is ±0.1 parts.

5. The method for preparing a hydrolysis-resistant glass fiber reinforced PBT composite material according to claim 1, characterized in that, In the step five, the length-diameter ratio of the double screw extruder is 36:1 to 40:1, melt mixing temperature is controlled in sections, the temperature from the feeding port to the die head is set as 230℃, 250℃, 260℃, 270℃, the screw speed is 500-700r / min, after extruding and granulating, also carry out devolatilization process treatment, devolatilization temperature is 70-90℃, devolatilization time is 1-3 hours, devolatilization equipment is vacuum devolatilization tank, vacuum degree is maintained at-0.08 to-0.1MPa.

6. A hydrolysis resistant glass fiber reinforced PBT composite material prepared by the method of any one of claims 1-5, characterized in that, It is made from the following weight parts of raw materials: PBT resin 65-70 parts, toughening agent 2-4 parts, glass fiber 28-32 parts, hydrolysis resistant agent 0.5-1.5 parts, lubricant 0.2-0.4 parts, antioxidant 0.5-0.7 parts.

7. The hydrolysis resistant glass fiber reinforced PBT composite material according to claim 6, characterized in that, The PBT resin is polybutylene terephthalate resin, its intrinsic viscosity is 0.95-1.05dL / g, carboxyl end group content is less than 10mol / t, the PBT resin is subjected to homogenization treatment before processing to ensure batch stability.

8. The hydrolysis resistant glass fiber reinforced PBT composite material according to claim 6, characterized in that, The toughening agent is selected from one or several of MBS, EBA-GMA or EMA-GMA, the adding method of the toughening agent is direct feeding or premixing into master batch, its particle size distribution is 50-200 microns.

9. The hydrolysis resistant glass fiber reinforced PBT composite material according to claim 6, characterized in that, The glass fiber is an alkali-free glass fiber, the surface of which is treated with a silane coupling agent, the content of the treating agent is 0.1-0.5%, and the dispersion uniformity of the glass fiber in the composite material is observed by microscope without agglomeration.

10. The hydrolysis resistant glass fiber reinforced PBT composite material according to claim 6, characterized in that, The hydrolysis-resistant agent is at least one selected from monomeric carbodiimide, polymeric carbodiimide, isocyanate or oxazoline compound, the lubricant is one or several of vinyl bis-stearamide, pentaerythritol stearate or silicone, and the antioxidant is a composite system of hindered phenolic antioxidant and phosphite antioxidant, wherein the hindered phenolic antioxidant is selected from antioxidant 1010, antioxidant 1076 or antioxidant 1098, and the phosphite antioxidant is selected from antioxidant 168 or antioxidant 626.