PBT / PET composite material, preparation method and application thereof

Abstract

The application discloses a PBT / PET composite material and a preparation method and application thereof, and belongs to the technical field of high polymer materials; the PBT / PET composite material provided by the application comprises the following components in parts by mass: PBT resin 30-60 parts, PET resin 5-25 parts, reinforcing agent 10-40 parts and expanding agent 0.4-5 parts; the expanding agent is an organic substance with a boiling point of 210-310 DEG C. The PBT / PET composite material provided by the application has high bonding line strength, excellent heat resistance and hydrolysis resistance, low specific gravity and wide application range, and can be especially applied to a flame-retardant reinforcing system. Moreover, the preparation method provided by the application is simple in operation and is beneficial to practical application.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and particularly relates to a PBT / PET composite material, its preparation method and application. Background Technology

[0002] Bond line defects are very common in plastic products. First, modified plastics have the lowest molten front temperature, resulting in poor fusion; molten fronts from different directions converge but fail to fully fuse. Second, in glass fiber reinforced materials, the glass fibers are arranged parallel to the bond line on both sides, not perpendicular to it and interlacing, thus failing to provide reinforcement. Third, the molten plastic on both sides of the bond line cools and contracts in opposite directions, especially in crystalline materials, leading to significant internal stress at the bond line. Poor bond line fusion easily causes bond line cracking.

[0003] PBT is a semi-crystalline material with a relatively high shrinkage rate, making it more prone to weld line cracking. Existing techniques for improving weld line strength all have varying degrees of problems. For example, CN110819082A discloses a high weld line strength glass fiber reinforced PBT composite material and its preparation method, which improves the weld line strength of the glass fiber reinforced PBT material by adding an acrylate-acrylamide copolymer with an acrylamide content ranging from 20% to 40% to PBT; however, the acrylate-acrylamide copolymer in this method reduces the material's hydrolysis resistance. CN113956642A discloses a high weld line strength PC / PBT composition and its preparation method, which improves the weld line strength of PC / PBT by adding a block copolymer of glycidol and polycarbonate diol; however, the glycidol-polycarbonate diol block copolymer in this method is only applicable to PC / PBT alloys and is ineffective in flame-retardant reinforced PBT systems, severely limiting its application. Therefore, it is very important to develop a PBT modified material that improves bonding strength and has broad applicability, especially for flame-retardant reinforced systems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a PBT / PET composite material with high bonding strength, excellent heat resistance and hydrolysis resistance, low specific gravity and wide applicability, especially suitable for flame-retardant reinforced systems, as well as its preparation method and application.

[0005] To achieve the above objectives, in a first aspect of the present invention, the present invention provides a PBT / PET composite material comprising the following components in parts by weight: 30-60 parts of PBT resin, 5-25 parts of PET resin, 10-40 parts of reinforcing agent, and 0.4-5 parts of expanding agent; wherein the expanding agent is an organic compound with a boiling point between 210-310°C.

[0006] This invention provides a PBT / PET composite material. By adding the above-mentioned components within a specific mass range, the components exhibit excellent synergistic effects, ensuring high bond strength, excellent heat resistance and hydrolysis resistance, low specific gravity, and wide applicability of the prepared composite material, especially suitable for flame-retardant reinforced systems. Specifically, PBT resin and PET resin can undergo transesterification, thereby disrupting the crystallization behavior of PBT resin, reducing the cooling rate of PBT, and improving the bond strength of the material to a certain extent. During the cooling process, the molten adhesive on both sides of the bond line contracts in opposite directions, and the bond line is subjected to tensile stress. This invention selects organic substances within a suitable boiling point range as expanding agents. The selected expanding agents undergo physical vaporization upon heating to generate inert gases, increasing the internal pressure of the molten adhesive, thereby extruding the molten adhesive on both sides of the bond line in opposite directions, disrupting the orientation distribution at the bond line, and achieving the effect of improving bond strength. Furthermore, the generated bubbles can reduce weight to a certain extent, which is beneficial for product lightweighting. At the same time, glass fibers with a diameter within a certain range are further specified as reinforcing agents, which can cooperate with the expanding agents to achieve good heat resistance of the composite material while ensuring bond strength.

[0007] The boiling point of the expanding agent is tested under standard atmospheric pressure. The principle of the method is that when the temperature of the liquid increases, its vapor pressure increases accordingly. When the vapor pressure of the liquid equals the atmospheric pressure, it begins to boil, and the temperature at this point is the boiling point.

[0008] For example, the boiling point of the expanding agent can be any point value or a range of any two points between 210-310℃, such as 210℃, 212℃, 214℃, 216℃, 218℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 282℃, 284℃, 286℃, 288℃, 290℃, 292℃, 294℃, 296℃, 298℃, 300℃, 302℃, 304℃, 306℃, 308℃, 310℃, etc. Within the 210-310℃ range given in this invention, the effects of this invention can be achieved.

[0009] For example, in the PBT composite material, the number of parts of PBT resin can be any point value or any two points between 30 and 60 parts, such as 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, etc.; the number of parts of PET resin can be any point value or any two points between 5 and 25 parts, such as 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, etc.; the number of parts of reinforcing agent can be any point value or any two points between 10 and 40 parts, such as the number of parts of reinforcing agent... The quantities can be 10, 12, 15, 18, 20, 22, 25, 28, 30, 32, 35, 38, 40, etc.; the quantity of the expanding agent can be any point value or any range between 0.4 and 5 parts, for example, the quantity of the expanding agent can be 0.4, 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, etc. Due to space limitations, they are not listed here. Within the mass fraction range of the components given in this invention, the effects of this invention can be achieved.

[0010] In the PBT composite material, the mass percentage of PBT resin is not less than 25%, and the mass percentage of PET resin is not less than 4%.

[0011] As a preferred embodiment of the PBT / PET composite material of the present invention, the PBT / PET composite material comprises the following components in parts by weight: 35-55 parts of PBT resin and 8-20 parts of PET resin.

[0012] The inventors discovered that when the mass fractions of PBT resin and PET resin are within the above-mentioned range, superior heat resistance, hydrolysis resistance, and better bond strength can be achieved.

[0013] As a preferred embodiment of the PBT / PET composite material of the present invention, at least one of the following (a)-(c) is used:

[0014] (a) The intrinsic viscosity of the PBT resin is 0.7-1.30 dl / g;

[0015] (b) The intrinsic viscosity of the PET resin is 0.66-1.10 dl / g;

[0016] (c) The expanding agent is at least one of dimethyl terephthalate, methylparaben, ethylparaben, methyl p-methylbenzoate, ethyl p-methylbenzoate, R-propylene carbonate, diphenyl carbonate, and dimethyl phthalate.

[0017] The specific viscosity of PBT resin and PET resin is determined with reference to GB / T 14190-2017. Specifically, the test is conducted in a constant temperature water bath using an Ubbelohde viscometer. The solvent selected is a mixture of phenol and tetrachloroethane with a mass ratio of phenol:tetrachloroethane = 3:2, and the test temperature is 25℃.

[0018] This invention does not impose specific requirements on the viscosity of PBT resin and PET resin; for example, the intrinsic viscosity of the PBT resin may be 0.7 dl / g, 0.75 dl / g, 0.8 dl / g, 0.85 dl / g, 0.9 dl / g, 0.95 dl / g, 1.0 dl / g, 1.05 dl / g, 1.1 dl / g, 1.15 dl / g, 1.2 dl / g, 1.25 dl / g, or 1.3 dl / g; for example, the intrinsic viscosity of the PET resin may be 0.66 dl / g, 0.7 dl / g, 0.75 dl / g, 0.8 dl / g, 0.85 dl / g, 0.9 dl / g, 0.95 dl / g, 1.0 dl / g, 1.05 dl / g, or 1.1 dl / g.

[0019] The inventors discovered that when the selected expanding agent is one of the above-mentioned components, the overall effect of the product is superior.

[0020] In a preferred embodiment of the PBT / PET composite material of the present invention, the average diameter of the glass fiber is <15μm.

[0021] For example, the average diameter of the glass fiber can be any point value or a range formed by any two points of <15μm, such as 7μm, 10μm, 11μm, 13μm, 14μm, etc. Due to space limitations, they are not listed here. The effects of the present invention can be achieved within the range of <15μm given in the present invention.

[0022] Preferably, the glass fibers used in the embodiments have an average diameter of 7-11 μm.

[0023] When the average diameter of the glass fibers is further optimized, the resulting product has a higher heat distortion temperature and a lower density; specifically, the resulting product has a heat distortion temperature above 200°C and a density of 1.33 g / cm³. 3 the following.

[0024] The method for testing the average diameter of the glass fibers is as follows: PBT / PET composite plastic particles are calcined in a muffle furnace at 600℃ for 2 hours, and the diameter of the residual ash after calcination is measured under an optical microscope. If necessary, the residual ash can be immersed in an aqueous solution and ultrasonically dispersed before being measured under an optical microscope. The average fiber diameter is determined by the number-average fiber diameter of 100 consecutive glass fibers under an optical microscope.

[0025] In a preferred embodiment of the PBT / PET composite material of the present invention, the expanding agent is an organic compound with a boiling point between 241 and 305°C.

[0026] The inventors discovered that when the expanding agent is further optimized to be an organic compound with a boiling point between 241-305℃, the overall effect of the product is even better.

[0027] As a preferred embodiment of the PBT / PET composite material of the present invention, the PBT / PET composite material further includes 10-20 parts of brominated flame retardant and 2-8 parts of flame retardant synergist.

[0028] For example, the brominated flame retardant can be any point value or any two points between 10 and 20 parts, such as 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts, etc.; the flame retardant synergist can be any point value or any two points between 2 and 8 parts, such as 2, 3, 4, 5, 6, 7, 8 parts, etc.

[0029] The inventors have discovered that when conventional brominated flame retardants and flame retardant synergists are introduced into the system of this invention, the product's bond strength, heat resistance, and water resistance are not significantly altered while achieving the flame retardant effect.

[0030] Preferably, the brominated flame retardant is at least one of brominated polycarbonate, brominated polystyrene, brominated epoxy resin, decabromodiphenyl ethane, pentabromobenzyl polyacrylate, and bromotriazine; and the flame retardant synergist is at least one of antimony trioxide and sodium antimonate.

[0031] As a preferred embodiment of the PBT / PET composite material of the present invention, the PBT / PET composite material further includes 1-8 parts of toughening agent and 0-2 parts of processing aid.

[0032] For example, the toughening agent may be at least one of the following: ethylene-methyl acrylate-glycidyl methacrylate terpolymer, ethylene-butyl acrylate-glycidyl methacrylate terpolymer, glycidyl methacrylate-grafted ethylene-butyl acrylate copolymer, glycidyl methacrylate-grafted ethylene-methyl acrylate copolymer, ethylene-butyl acrylate, and ethylene-methyl acrylate.

[0033] For example, the processing aid is at least one of antioxidants, lubricants, nucleating agents, laser aids, weathering agents, and anti-drip agents.

[0034] In a second aspect of the present invention, the present invention provides a method for preparing the PBT / PET composite material, the method comprising the following steps: mixing the components uniformly and then melt-extruding to obtain the PBT / PET composite material.

[0035] In a preferred embodiment of the preparation method described in this invention, the temperature of the melt extrusion is 210-250°C.

[0036] In a third aspect, the present invention provides the application of the PBT / PET composite material in electronics, new energy, and household appliances.

[0037] For example, the application can be in motor stators in the field of electronics and electrical engineering, charging gun end plates in the field of new energy, and gears in the field of household appliances.

[0038] In application, for PBT / PET composite materials, the extrusion temperature range is generally between 200-260℃, and the injection molding temperature range is between 230-290℃.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] This invention provides a PBT / PET composite material that, through the addition of components within a specific mass range, exhibits excellent synergistic effects among the components. This ensures the prepared composite material possesses high bond strength, excellent heat resistance and hydrolysis resistance, low specific gravity, and wide applicability, particularly suitable for flame-retardant reinforced systems. Specifically, the obtained composite material has a bond strength exceeding 47.1 MPa, a water-boiling tensile strength retention rate exceeding 85.9%, a heat distortion temperature between 191-204℃, and a density between 1.23-1.48 g / cm³. 3 Furthermore, by introducing flame retardants and flame retardant synergists, the resulting product not only possesses flame retardancy but also maintains excellent bond line strength, water boiling tensile strength retention rate, heat distortion temperature, and low specific gravity. Simultaneously, the preparation method provided by this invention is simple to operate and beneficial for practical applications. Detailed Implementation

[0041] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0042] Unless otherwise specified, the raw materials used in this invention are conventional commercially available raw materials, and the raw materials used in the parallel embodiments or comparative examples of this invention are the same.

[0043] PBT: PBT GX121, intrinsic viscosity 1.00 dl / g, Yizheng Branch of China Petrochemical Corporation Asset Management Co., Ltd.

[0044] PET: PET FG600, intrinsic viscosity 0.68 dl / g, Yizheng Branch of China Petrochemical Corporation Asset Management Co., Ltd.

[0045] Reinforcing agent: Alkali-free glass fiber, ECS11-4.5-534A, glass fiber diameter is 11μm, Jushi Group Co., Ltd.;

[0046] Expanding agent 1: Dimethyl terephthalate, CAS No. 120-61-6, boiling point 288℃, Anaiji Chemical Reagent;

[0047] Expanding agent 2: Ethyl paraben, CAS number 120-47-8, boiling point 297.5℃, Anaiji Chemical Reagent;

[0048] Expanding agent 3: R-propylene carbonate, CAS number 16606-55-6, boiling point 241.72℃, Anaiji Chemical Reagent;

[0049] Expanding agent 4: di-o-toluene carbonate, CAS number 617-09-4, boiling point 341℃, Anaiji Chemical Reagent;

[0050] Expanding agent 5: dibutyl carbonate, CAS number 542-52-9, boiling point 207℃, Anaiji Chemical Reagent;

[0051] Flame retardant 1: Brominated polycarbonate, FG-8500, Teijin, Japan;

[0052] Flame retardant 2: Brominated polystyrene, BPS 7010, Shandong Tianyi Chemical Co., Ltd.;

[0053] Flame retardant 3: Brominated epoxy resin, powder-F-2100, Israel Chemicals;

[0054] Flame retardant 4: Decabromodiphenyl ethane, Saytex 8010, Albemarle, USA;

[0055] Flame retardant 5: Organophosphonate, BEP-22H, Zhuhai Wantong Chemical Co., Ltd.;

[0056] Synergist: Antimony trioxide, S-12N, purity 99.8%, Hunan Xikuangshan Shanxing Antimony Industry Import & Export Co., Ltd.;

[0057] Toughening agent: Ethylene-methyl acrylate-glycidyl methacrylate terpolymer, AX8900, Arkema China Investment Co., Ltd.;

[0058] Lubricant: Pentaerythritol fatty acid ester, commercially available;

[0059] Antioxidant: Pentaerythritol tetrakis[β(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], commercially available.

[0060] Examples 1-13 and Comparative Examples 1-7

[0061] Examples 1-13 and Comparative Examples 1-7 of the present invention provide a PBT / PET composite material, the composition (parts by mass) of the composite material is shown in Table 1-2;

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066]

[0067] The preparation method of the PBT / PET composite material provided in Examples 1-13 and Comparative Examples 1-7 is as follows: after the components are mixed evenly, they are melt-extruded at 240°C to obtain the PBT / PET composite material.

[0068] Example of effect

[0069] This example verifies the performance of the PBT / PET composite materials prepared in Examples 1-13 and Comparative Examples 1-7, specifically including the following aspects:

[0070] 1. Tensile strength of the bond line: The tensile strength of the bond line is tested according to ISO 527-2:2012. The specimen size is 150*10*4mm and the tensile speed is 10mm / min. The injection temperature of the bond line tensile strength specimen is 250℃. Medium pressure and low speed injection molding is used. The specimen is injected from both ends and the bond line is located in the middle of the specimen.

[0071] 2. Water boiling tensile strength retention rate: The water boiling conditions are 100℃ for 168 hours; the water boiling tensile strength test is carried out according to ISO527-2:2012, the sample size is 150*10*4mm, the tensile speed is 10mm / min; the test specimen is glued at both ends, and the bonding line is located in the middle of the specimen;

[0072] 3. Flame retardant rating: Tested according to UL94 vertical burning standard, the sample size is 127*12.7*0.8mm.

[0073] The test data are shown in Table 3; however, no flame retardancy rating test was conducted on the products in Examples 1-7 and Comparative Examples 1-5, which are indicated by “ / ”.

[0074] Table 3

[0075]

[0076]

[0077] As can be seen from Examples 1-7 and Comparative Examples 1-5 in Table 3, when the technical solution provided by the present invention is adopted, the obtained PBT / PET composite material has the characteristics of high bonding tensile strength, water resistance, excellent heat resistance and low specific gravity. Among them, the bonding tensile strength of the prepared PBT / PET composite material is above 48.9 MPa and the water boiling tensile strength retention rate is above 85.9%.

[0078] As can be seen from Examples 1-5 and Comparative Examples 2-3, the mass fraction of the components has a certain impact on the performance of the product. When the mass fraction of PBT resin is further optimized to be 35-55 parts and the mass fraction of PET resin is 8-20 parts, the overall performance of the product is better. The bond line tensile strength of the prepared PBT / PET composite material is above 50.9 MPa, and the boiling water tensile strength retention rate is above 87.6%. When the mass fraction of PET resin in Comparative Example 3 is too small, the bond line tensile strength of the product is greatly reduced. Compared with Example 1, the bond line tensile strength decreased by 25.3%, and the boiling water tensile strength retention rate also showed a downward trend.

[0079] As can be seen from Example 1 and Comparative Example 1, when no expanding agent is added, the retention rate of the tensile strength of the product after boiling is significantly reduced, decreasing by 55.5% compared with Example 1, and the tensile strength of the bond line of the product also shows a decreasing trend, with a decrease of 18.5%.

[0080] As can be seen from Examples 1, 6-7 and Comparative Examples 4-5, the choice of expanding agent also affects the performance of the product. When the boiling point of the expanding agent is not within the range given in this invention, the tensile strength of the bond line and the retention rate of the boiling tensile strength of the obtained product are significantly reduced, especially the boiling tensile strength. Compared with Example 1, the boiling tensile strength of Comparative Examples 4-5 decreased by 52.2-54.1%.

[0081] As can be seen from Examples 1 and 8-13, when brominated flame retardants and flame retardant synergists are further introduced into the system, the changes in the bond line strength and boiling water resistance of the obtained products are minimal. Compared with Example 1, when different flame retardants are introduced in Examples 8-11, the change in bond line tensile strength is less than 5.8%, and the change in boiling water tensile strength is less than 1.5%. Moreover, when different flame retardants are selected, the boiling water tensile strength shows an increasing trend, and the flame retardant rating of the obtained products all reaches UL94 V-0 level, indicating that the system provided by the present invention has good applicability and can be applied to brominated flame retardant reinforcement systems. Furthermore, Examples 8-11 show that the system provided by the present invention has good compatibility with different brominated flame retardants. As can be seen from Examples 8 and Comparative Example 7, when other types of flame retardants are introduced, the bond line tensile strength of the obtained products decreases significantly, and the boiling water tensile strength retention rate also shows a significant decreasing trend. In addition, as can be seen from Examples 8 and Comparative Example 6, the introduction of an intumescent agent can help achieve good bond line tensile strength of the flame retardant system.

[0082] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PBT / PET composite material, characterized in that, The PBT / PET composite material comprises the following components in parts by weight: 30-60 parts PBT resin, 5-25 parts PET resin, 10-40 parts reinforcing agent, and 0.4-5 parts expanding agent; The expanding agent is an organic compound with a boiling point between 210-310℃; The expanding agent is at least one of dimethyl terephthalate, methylparaben, ethylparaben, methyl p-methylbenzoate, ethyl p-methylbenzoate, R-propylene carbonate, diphenyl carbonate, and dimethyl phthalate. The PBT / PET composite material also includes 10-20 parts of brominated flame retardant and 2-8 parts of flame retardant synergist.

2. The PBT / PET composite material according to claim 1, characterized in that, The PBT / PET composite material comprises the following components in parts by weight: 35-55 parts of PBT resin and 8-20 parts of PET resin.

3. The PBT / PET composite material according to claim 1, characterized in that, At least one of the following (a)-(b): (a) The intrinsic viscosity of the PBT resin is 0.7-1.30 dl / g; (b) The intrinsic viscosity of the PET resin is 0.66-1.10 dl / g.

4. The PBT / PET composite material according to claim 1, characterized in that, The average diameter of the reinforcing agent is <15 μm.

5. The PBT / PET composite material according to claim 1, characterized in that, The expanding agent is an organic compound with a boiling point between 241 and 305°C.

6. The PBT / PET composite material according to claim 1, characterized in that, The brominated flame retardant is selected from at least one of brominated polycarbonate, brominated polystyrene, brominated epoxy resin, decabromodiphenyl ethane, pentabromobenzyl polyacrylate, and bromotriazine; the flame retardant synergist is selected from at least one of antimony trioxide and sodium antimonate.

7. The PBT / PET composite material according to claim 1, characterized in that, The PBT / PET composite material also includes 1-8 parts toughening agent and 0-2 parts processing aid.

8. The method for preparing the PBT / PET composite material according to any one of claims 1-7, characterized in that, The preparation method includes the following steps: mixing the components evenly and then melting and extruding to obtain PBT / PET composite material.

9. The application of the PBT / PET composite material as described in any one of claims 1-7 in electronics, electrical engineering, new energy, and household appliances.

Images