A PBT composite material and its preparation method and application

Abstract

The invention discloses a PBT composite material, which comprises the following components by weight: 100 parts of PBT resin; 0-100 parts of glass fiber; 0.5-10 parts of ethylene-butyl acrylate-glycidyl methacrylate copolymer; and 0.5-2 parts of dipentaerythritol; wherein the weight ratio of ethylene-butyl acrylate-glycidyl methacrylate copolymer to dipentaerythritol is (10-1):1. The invention adds a specific amount of dipentaerythritol to the PBT composite material, which can react with the small molecular PBT chain segments generated by the degradation of the PBT resin during the melting shearing process to generate a cross-linked structure, thereby regulating the crystallization rate of the PBT; and the ethylene-butyl acrylate-glycidyl methacrylate copolymer can react with the terminal carboxyl group of the PBT, play the role of a capping agent, reduce the nucleation effect of the terminal carboxyl group, thereby reducing the crystallization temperature and improving the mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a PBT composite material and a preparation method and application thereof. Background Art

[0002] PBT is an engineering plastic with excellent performance. It has many advantages such as high mechanical strength, good fatigue resistance, good dimensional stability, and good solvent resistance. It is widely used in electronic appliances, home appliances, automobiles, textiles and other industries. PBT is a semi-crystalline polymer with a fast crystallization rate and good crystallization performance, and therefore has good performance in molding processing. However, in actual industrial applications, it is found that glass fiber reinforced PBT materials are easier to crystallize after modification, with a higher crystallization temperature and faster crystallization rate, which leads to problems such as warping and cold glue in the processing of complex structural parts, limiting the expansion of the application range of PBT in the molding of fine parts.

[0003] In order to solve the warping problem during the processing of glass fiber reinforced PBT materials and develop glass fiber reinforced PBT materials with higher dimensional stability, low-crystalline resins with good fluidity, such as PC, PET, etc., are usually blended. For example, patent CN111286163A improves the crystallization performance of PBT by adding amorphous resin PC to achieve low warpage products. However, blending low-crystalline materials will reduce the crystallinity while lowering the crystallization temperature of PBT, resulting in reduced mechanical properties of the material. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical defects and provide a PBT composite material with low crystallization temperature and good mechanical properties, and a preparation method and application thereof.

[0005] The present invention is achieved through the following technical solutions:

[0006] A PBT composite material, comprising the following components in parts by weight:

[0007] PBT resin 100 parts;

[0008] Glass fiber 0-100 parts;

[0009] 0.5-10 parts of ethylene-butyl acrylate-glycidyl methacrylate copolymer;

[0010] Dipentaerythritol 0.5-2 parts;

[0011] Wherein, the weight ratio of ethylene-butyl acrylate-glycidyl methacrylate copolymer to dipentaerythritol is in the range of (10-1):1.

[0012] Preferably, the weight ratio of ethylene-butyl acrylate-glycidyl methacrylate copolymer to dipentaerythritol is in the range of (8-3):1.

[0013] The relative viscosity range of PBT resin is 1.3500-1.9000. The specific test method is: measure the relative viscosity ηr of polyester with a concentration of 10 mg / mL in 98% concentrated sulfuric acid at 25℃±0.01℃.

[0014] The diameter of the glass fiber is in the range of 7-20 microns, preferably 11-13 microns.

[0015] The melt index range of ethylene-butyl acrylate-glycidyl methacrylate copolymer is 4-12g / 10min. The specific test method is: ASTM D1238 (190℃, 2.16kg)

[0016] You can choose whether to add 0-1 part of antioxidant according to actual needs.

[0017] The antioxidant may be: 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; 2,5-di-tert-butyl-4-hydroxybenzyl dimethylamine; diethyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphate; stearyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphate; 3,5-di-tert-butyl-4-hydroxyphenyl-3,5-distearyl-thiotriazolylamine; 2,6-di-tert-butyl-4-hydroxymethylphenol; 2,4-di-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylglycerol allyl ether)-1,3,5-triazine; N,N'-hexamethylenediamine; (3,5-di-tert-butyl-4-hydroxy-hydrocinnamic acid); N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine; octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]; triethylene glycol-bis[3-(3,5-dimethyl-4-hydroxyphenyl) propionate]; triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate]; 2,2'-thiodiethyl-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, etc.

[0018] The crystallization temperature range of PBT composites is 181-193°C.

[0019] The preparation method of the PBT composite material of the invention comprises the following steps: mixing, dispersing, melting and extruding, granulating PBT resin, ethylene-butyl acrylate-glycidyl methacrylate copolymer and dipentaerythritol through a twin-screw extruder, and feeding glass fiber sidewise, wherein the temperature section setting of the twin-screw extruder is divided into 10 sections, namely, the temperature of the first section is 220-240°C, the temperature of the second section is 230-245°C, the temperature of the third section is 235-245°C, the temperature of the fourth section is 235-250°C, the temperature of the fifth section is 220-240°C, the temperature of the sixth section is 220-240°C, the temperature of the seventh section is 210-230°C, the temperature of the eighth section is 200-220°C, the temperature of the ninth section is 200-220°C, the temperature of the tenth section is 220-240°C, the aspect ratio is 32-40:1, and the screw speed is 250-400 rpm.

[0020] The PBT composite material of the present invention is used to prepare parts with complex structures, such as mobile phone connectors, computer connectors, compressor parts, etc.

[0021] The present invention has the following beneficial effects

[0022] The invention adds a specific amount of dipentaerythritol to the PBT composite material, which can react with the small molecular PBT chain segments generated by the degradation of the PBT resin during the melting shearing process to generate a cross-linked structure, and can regulate the crystallization rate of the PBT; on this basis, the ethylene-butyl acrylate-glycidyl methacrylate copolymer can react with the terminal carboxyl group of the PBT, play the role of a capping agent, and reduce the nucleation effect of the terminal carboxyl group; the ethylene-butyl acrylate-glycidyl methacrylate copolymer and the dipentaerythritol cooperate with each other, further reduce the crystallization temperature, and improve the mechanical properties. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0024] The sources of raw materials used in the present invention are as follows:

[0025] PBT resin A: PBT GX121, relative viscosity 1.6306.

[0026] PBT resin B: PBT 1084, relative viscosity 1.3468.

[0027] PBT resin C: PBT GL236, relative viscosity 1.9471.

[0028] Dipentaerythritol: CHARMOR DP40.

[0029] Ethylene-butyl acrylate-glycidyl methacrylate copolymer: Elvaloy resins PTW, melt index is 12g / 10min (190℃, 2.16kg).

[0030] Ethylene-butyl acrylate-glycidyl methacrylate copolymer: KT-33, melt index is 4.2g / 10min (190℃, 2.16kg).

[0031] Other toughening agents A: grafted POE copolymer, KT-9.

[0032] Other toughening agents B: maleic anhydride grafted polypropylene copolymer, PC-1.

[0033] Glass fiber A: The diameter range is 7-10 microns, glass fiber E7CS10-03-534A.

[0034] Glass fiber B: The diameter range is 11-13 microns, glass fiber ECS13-4.5-534A.

[0035] Glass fiber C: diameter range is 14-20 microns, glass fiber EDR17-2400-960A.

[0036] Antioxidant: Pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], Antioxidant 1010.

[0037] Embodiment and comparative example PBT composite material preparation method: PBT resin, ethylene-butyl acrylate-glycidyl methacrylate copolymer, dipentaerythritol are mixed, dispersed, melt-extruded, and granulated by a twin-screw extruder, and glass fiber is fed on the side. The temperature section setting of the twin-screw extruder is divided into 10 sections, namely, the temperature of zone 1 is 220-240°C, the temperature of zone 2 is 230-245°C, the temperature of zone 3 is 235-245°C, the temperature of zone 4 is 235-250°C, the temperature of zone 5 is 220-240°C, the temperature of zone 6 is 220-240°C, the temperature of zone 7 is 210-230°C, the temperature of zone 8 is 200-220°C, the temperature of zone 9 is 200-220°C, the temperature of zone 10 is 220-240°C, the aspect ratio is 32-40:1, and the screw speed is 250-400 rpm.

[0038] Various test methods:

[0039] (1) Crystallization temperature: Weigh 5-10 mg of material and place it in an aluminum crucible to prepare a DSC sample. The equipment is NETZSCHDSC214. The temperature program is from 30-300°C, the heating rate is 10°C / min, and the temperature is kept constant for 5 minutes to eliminate the thermal history. Then, the temperature is cooled to 30°C at a cooling rate of 10°C / min under nitrogen protection. The temperature corresponding to the thermal signal peak that responds during the cooling process is the crystallization temperature of the material.

[0040] (2) Tensile strength: measured in accordance with GB / T1039-1992, and the tensile performance test was carried out on an electronic universal testing machine.

[0041] Table 1: Content of each component (parts by weight) and test results of PBT composite materials in Examples 1-7

[0042] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PBT Resin A 100 100 100 100 100 100 100 Glass Fiber A 50 5 100 50 Glass Fiber B 50 Glass Fiber C 50 Elvaloy resins PTW 5 5 5 0.5 5 KT-33 0.5 10 Dipentaerythritol 0.5 0.5 0.5 0.5 0.5 2 0.63 Crystallization temperature, °C 191.2 189.2 190.8 188.1 188.6 182.7 187.1 Tensile strength, MPa 129 134 128 51 66 149 132

[0043] It can be seen from Examples 1-3 that when glass fibers with a diameter range of 11-13 μm are preferred, the crystallization temperature is lower and the tensile strength is higher.

[0044] It can be seen from Examples 1 / 4 / 5 and Comparative Example 7 / 1 that an increase in glass fiber content promotes crystallization and thus increases the crystallization temperature, while the technical solution of the present invention can effectively reduce the crystallization temperature and increase the tensile strength.

[0045] Table 2: Content of each component (parts by weight) and test results of PBT composite materials in Examples 8-10

[0046] Example 8 Example 9 Example 10 Embodiment 11 Example 12 PBT Resin A 100 100 100 PBT resin B 100 PBT resin C 100 Glass Fiber A 50 50 50 50 50 Elvaloy resins PTW 5 5 5 5 5 Dipentaerythritol 1 1.67 2 0.5 0.5 Antioxidants - 0.1 Crystallization temperature, °C 184.3 182.9 181.5 191.5 191.0 Tensile strength, MPa 135 130 121 122 135

[0047] It can be seen from Examples 1 / 7-10 that the preferred weight ratio of ethylene-butyl acrylate-glycidyl methacrylate copolymer to dipentaerythritol is (8-3):1, which has a higher tensile strength and a crystallization temperature lower than 188°C.

[0048] Table 3: Content of each component (parts by weight) and test results of comparative PBT composite materials

[0049] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 PBT Resin A 100 100 100 100 100 100 100 Glass Fiber A 50 50 50 50 50 50 5 Elvaloy resins PTW 5 5 5 5 Other toughening agents A 5 Other toughening agents B 5 Dipentaerythritol 0 0.2 2.5 0.5 0.5 0.5 0 Crystallization temperature, °C 199.8 198.3 181.0 185.6 198.7 199.1 199.6 Tensile strength, MPa 122 125 102 89 127 123 61

[0050] It can be seen from Comparative Example 1 / 4 that the technical objectives of low crystallization temperature and high tensile strength can only be achieved when PTW and dipentaerythritol are present at the same time.

[0051] It can be seen from Comparative Examples 2 / 3 that if the content of dipentaerythritol is too low, the crystallization temperature does not decrease significantly, and the tensile strength does not increase significantly; if the content of dipentaerythritol is too high, the tensile strength decreases seriously.

[0052] It can be seen from Comparative Examples 5 / 6 that other toughening agents cannot cooperate with dipentaerythritol to achieve a decrease in crystallization temperature.

Claims

1. A PBT composite material, characterized in that: By weight, it includes the following components: PBT resin 100 parts; Glass fiber 5-100 parts; 0.5-10 parts of ethylene-butyl acrylate-glycidyl methacrylate copolymer; Dipentaerythritol 0.5-2 parts; The weight ratio of ethylene-butyl acrylate-glycidyl methacrylate copolymer to dipentaerythritol is (10-1):

1.

2. The PBT composite material according to claim 1, characterized in that: The weight ratio of ethylene-butyl acrylate-glycidyl methacrylate copolymer to dipentaerythritol is in the range of (8-3):

1.

3. The PBT composite material according to claim 1, characterized in that: The relative viscosity range of PBT resin is 1.3500-1.9000. The test method is: measure the relative viscosity ηr of polyester with a concentration of 10 mg / mL in 98% concentrated sulfuric acid at 25℃±0.01℃.

4. The PBT composite material according to claim 1, characterized in that: The diameter of the glass fiber is in the range of 7-20 microns.

5. The PBT composite material according to claim 4, characterized in that: The diameter of the glass fiber is in the range of 11-13 microns.

6. The PBT composite material according to claim 1, characterized in that: The melt index range of ethylene-butyl acrylate-glycidyl methacrylate copolymer is 4-12 g / 10 min, and the test condition is 190° C. / 2.16 kg.

7. The PBT composite material according to claim 1, characterized in that: By weight, 0-1 part of antioxidant is also included.

8. The PBT composite material according to any one of claims 1 to 7, characterized in that: The crystallization temperature range of PBT composites is 181-193°C.

9. The method for preparing the PBT composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: PBT resin, ethylene-butyl acrylate-glycidyl methacrylate copolymer, dipentaerythritol and an optional antioxidant are mixed, dispersed, melt-extruded and granulated through a twin-screw extruder, and glass fiber is fed from the side. The temperature section setting of the twin-screw extruder is divided into 10 sections, namely, the temperature of zone 1 is 220-240°C, the temperature of zone 2 is 230-245°C, the temperature of zone 3 is 235-245°C, the temperature of zone 4 is 235-250°C, the temperature of zone 5 is 220-240°C, the temperature of zone 6 is 220-240°C, the temperature of zone 7 is 210-230°C, the temperature of zone 8 is 200-220°C, the temperature of zone 9 is 200-220°C, the temperature of zone 10 is 220-240°C, the aspect ratio is 32-40:1, and the screw speed is 250-400 rpm.

10. Use of the PBT composite material according to any one of claims 1 to 8, characterized in that: Used to prepare mobile phone connectors, computer connectors, and compressor parts.