A PBT / recycled PET composite material and its preparation method and application

Abstract

The present invention discloses a PBT / recycled PET composite material, comprising the following components: 25-70 parts of PBT resin; 5-25 parts of recycled PET resin; 15-35 parts of alkali-free glass fiber; 10-25 parts of diethyl aluminum hypophosphite; 1-2 parts of melamine polyphosphate; 0.5-1 parts of halogen-free polyaryl phosphate; 0.3-0.5 parts of PA10T powder; and 0-1 parts of other functional processing aids; wherein the average particle size of the PA10T powder is ≤10 μm. The PBT / recycled PET composite material of the present invention, by selecting a specific flame retardant system and simultaneously adding a certain amount of PA10T, solves the mold sticking and bursting problems caused by the addition of recycled PET resin in the prior art during the material processing and molding process, effectively improves the heat resistance and mechanical properties of the material, and obtains a halogen-free flame-retardant PBT / recycled PET composite material that can meet the requirements of high-heat-resistant products, allowing the effective reuse of recycled PET. This is of great significance in the research of realizing the high-value utilization of waste plastics.

Description

Technical Field

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

[0002] Polybutylene terephthalate (PBT) is a crystalline thermoplastic polyester with advantages such as rapid prototyping, chemical resistance, excellent electrical insulation, and high-temperature resistance. It is widely used in various fields, including electronics, lighting, home appliances, and automobiles. Polyethylene terephthalate (PET) has a similar chemical structure and properties to PBT, and the two are highly compatible. PET is also more affordable than PBT, so a certain proportion of PET is often added to PBT to create a PBT / PET alloy with superior overall performance and a higher cost-performance ratio.

[0003] With the substantial increase in the use of plastics, recycling and reusing waste plastics as resources has become a top priority for environmental protection in countries around the world. How to achieve high-value utilization of waste plastics is currently one of the research hotspots in this field. Recycled PET mainly comes from discarded PET bottles after consumption. However, since PET molecules inevitably degrade during the recycling and reprocessing process, the performance of recycled PET decreases. It is difficult to obtain better mechanical properties when using recycled PET in PBT materials. In addition, it is prone to problems such as mold sticking and bursting during the processing and molding process. In addition, it has poor heat resistance and the parts are easily deformed by heat, making it difficult to meet the requirements of use. At present, there are still major technical difficulties in the practical application of recycled PET. Summary of the Invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a halogen-free flame-retardant PBT / recycled PET composite material using recycled PET, which has excellent processability, mechanical properties and heat resistance.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned PBT / recycled PET composite material.

[0006] The present invention is achieved through the following technical solutions:

[0007] A PBT / recycled PET composite material, comprising the following components in parts by weight:

[0008] 25-70 parts of PBT resin;

[0009] Recycle 5-25 parts of PET resin;

[0010] 15-35 parts of alkali-free glass fiber;

[0011] 10-25 parts of diethyl aluminum hypophosphite;

[0012] 1-3 parts of melamine polyphosphate;

[0013] 0.5-1 part of halogen-free polyaryl phosphate;

[0014] 0.3-0.5 parts of PA10T powder;

[0015] Other functional processing aids 0-1 part;

[0016] The average particle size of the PA10T powder is ≤10 μm.

[0017] The weight percentage of the PBT resin can be 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts or 70 parts, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0018] Preferably, the intrinsic viscosity of the PBT resin at 25°C is 0.7-1.0 dL / g. The intrinsic viscosity is tested in accordance with GB / T 14190-2017. Specifically, the intrinsic viscosity of the PBT resin of the present invention is tested in a phenol-tetrachloroethane solvent (with a mass ratio of phenol to tetrachloroethane of 3:2).

[0019] The weight percentages of the recycled PET resin can be 5 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts or 20 parts, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0020] Preferably, the recycled PET resin has an intrinsic viscosity of 0.65-0.8 dL / g at 25°C. The intrinsic viscosity is tested in accordance with GB / T 14190-2017. Specifically, the intrinsic viscosity of the recycled PET resin of the present invention is tested in a phenol-tetrachloroethane solvent (a mass ratio of phenol to tetrachloroethane of 3:2).

[0021] Preferably, the weight ratio of the PBT resin to the recycled PET resin is (1-14):1. For example, the weight ratio may be 1:1, 2:1, 4:1, 6:1, 8:1, 10:1, 12:1, or 14:1, as well as specific values ​​between the aforementioned values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively enumerate the specific values ​​included in the aforementioned range.

[0022] The recycled PET resin of the present invention mainly comes from post-consumer waste PET bottles, including mineral water bottles, beverage bottles, etc.

[0023] The PBT / recycled PET composite material of the present invention can contain recycled PET resin at a weight percentage of 4 wt% or greater, preferably between 4 wt% and 30 wt%. For example, the weight percentage can be 4 wt%, 8 wt%, 12 wt%, 16 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, 28 wt%, or 30 wt%, as well as specific values ​​in between. Due to space limitations and for the sake of brevity, the present invention does not exhaustively enumerate the specific values ​​within the aforementioned ranges.

[0024] Preferably, the aryl group of the halogen-free polyaryl phosphate has no substituent. Furthermore, the halogen-free polyaryl phosphate is preferably any one or more of bisphenol A bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate), or hydroquinone bis(diphenyl phosphate).

[0025] Preferably, the average particle size of the PA10T powder is 1 μm to 9 μm. In the present invention, PA10T powder of the desired particle size can be obtained by crushing the PA10T powder with a pulverizer and then sieving it. The average particle size of the PA10T powder can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, as well as specific values ​​between the aforementioned values. Due to space limitations and for the sake of simplicity, this invention does not exhaustively list the specific values ​​within the aforementioned range. The average particle size can be measured using a Malvern particle size analyzer.

[0026] Preferably, the diameter of the alkali-free glass fiber is ≤15 μm and the length is 3-5 mm; more preferably, the diameter of the alkali-free glass fiber is 7-10 μm and the length is 3-4 mm.

[0027] The other functional processing aids of the present invention include at least one of an antioxidant or a lubricant.

[0028] The lubricant is preferably any one or more of aliphatic carboxylic acid esters, erucamide, ethylene bisstearamide, montan esters, polyethylene wax or oxidized polyethylene wax.

[0029] The antioxidant is preferably any one or more of a hindered phenol antioxidant, a phosphite antioxidant, or an organic sulfur antioxidant. Furthermore, the hindered phenol antioxidant may be selected from at least one of 2,6-tert-butyl-4-methylphenol, bis(3,5-tert-butyl-4-hydroxyphenyl)sulfide, or pentaerythritol tetrakis[β-(3,5-tert-butyl-4-hydroxyphenyl)propionate]; the phosphite antioxidant may be selected from at least one of trioctyl phosphite or tridecyl phosphite; and the organic sulfur antioxidant may be selected from at least one of didodecanol thiodipropionate or didetradecyl thiodipropionate.

[0030] The present invention also provides a method for preparing the above-mentioned PBT / recycled PET composite material, comprising the following steps:

[0031] (1) PBT resin and recycled PET resin are first dried and then mixed with other components except alkali-free glass fiber in a high-speed stirring mixer according to the proportion or fed separately into a premixer through a metering feeder;

[0032] (2) The mixed material is fed into a twin-screw extruder, and alkali-free glass fiber is added to the side feed. Under the conveying and shearing action of the twin-screw extruder, the mixed material is fully melted and plasticized, kneaded and mixed, extruded through the die head, stretched, cooled, pelletized, and dried to prepare a PBT / recycled PET composite material.

[0033] Preferably, the PBT resin and the recycled PET resin are pre-dried at 120-140° C. for 4-6 hours and then blended with other components.

[0034] Preferably, the feeding rate of the twin-screw extruder is 450-800 kg / hour; the temperatures of each section of the screw of the twin-screw extruder from the feeding port to the die are 220-230°C, 230-240°C, 203-240°C, 240-250°C, 250-260°C, 240-250°C, 240-250°C, 230-240°C, and 230-240°C, and the screw speed is 250-400 rpm.

[0035] The present invention also provides applications of the PBT / recycled PET composite material in the field of electronics and electrical equipment, particularly for products with high requirements for formability and heat resistance, such as connectors, chargers, and motor components.

[0036] The present invention has the following beneficial effects:

[0037] The PBT / recycled PET composite material of the present invention utilizes recycled PET resin. By selecting a specific diethylaluminum hypophosphite-melamine polyphosphate-halogen-free polyaryl phosphate flame retardant system and adding a certain amount of PA10T, the composite material solves the mold sticking and bursting problems caused by the addition of recycled PET resin in the prior art. The composite material also effectively improves the heat resistance and mechanical strength of the material to a certain extent, resulting in a halogen-free flame-retardant PBT / recycled PET composite material that meets the requirements of high-heat-resistant products. The present invention enables the effective reuse of recycled PET and is of great significance in the research of high-value utilization of waste plastics. Implementation Method

[0038] The present invention will be described in detail below with reference to 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 skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0039] The raw materials used in the examples and comparative examples of the present invention are described below, but are not limited to these materials:

[0040] PBT resin 1: Yizheng PBTGX111, intrinsic viscosity 0.73dL / g;

[0041] PBT resin 2: Holly PBT L08XM, intrinsic viscosity 0.83 dL / g;

[0042] PBT resin 3: Heshili PBT L10XM, intrinsic viscosity 1.0 dL / g;

[0043] PBT resin 4: Yizheng PBT GL236, intrinsic viscosity 1.3 dL / g;

[0044] Recycled PET resin 1: Yonghong PET-YH002, intrinsic viscosity 0.73dL / g;

[0045] Recycled PET resin 2: Seville JZL-CEV203OBCR, intrinsic viscosity 0.68 dL / g;

[0046] Diethylaluminum hypophosphite: Clariant Chemicals Exolit OP 1230;

[0047] Melamine polyphosphate: Budenheim BUDIT 341;

[0048] E-glass fiber 1: Jushi Glass Fiber ECS11-4.5-534A, diameter 11μm, length 4.5mm;

[0049] E-glass fiber 2: HMG436S-10-4.0 from Taishan Glass Fiber Co., Ltd., with a diameter of 10 μm and a length of 4.0 mm;

[0050] Halogen-free polyaryl phosphate 1: ADK STAB FP-600, ADK, bisphenol A bis(diphenyl phosphate);

[0051] Halogen-free polyaryl phosphate 2: WSFR-PX-220, Wansheng, hydroquinone bis(diphenyl phosphate);

[0052] Halogen-free polyaryl phosphate 3: PX-200, Daba Chemical, resorcinol bis[di(2,6-dimethylphenyl) phosphate];

[0053] PA10T-1: KFHP10, Zhuhai Wantong, crushed with a grinder and sieved to obtain PA10T powder with an average particle size of 7.6 μm;

[0054] PA10T-2: KFHP10, Zhuhai Wantong, crushed with a grinder and sieved to obtain PA10T powder with an average particle size of 21.4 μm;

[0055] Other functional processing aids 1: antioxidant, antioxidant 1010 and antioxidant 168 are mixed in a ratio of 1:3, commercially available; the same antioxidant is used in the examples and comparative examples;

[0056] Other functional processing aids 2: Lubricant PETs, aliphatic carboxylic acid ester, commercially available; the same lubricant was used in the examples and comparative examples.

[0057] Preparation methods of Examples and Comparative Examples:

[0058] (1) Pre-dry the PBT resin and the recycled PET resin at 120°C for more than 4 hours, and control the moisture content to less than 0.03%; then mix the dried PBT resin, the recycled PET resin and the other components except the alkali-free glass fiber in a high-speed stirring mixer according to the proportions in Table 1 to obtain a mixture;

[0059] (2) The mixed material is fed into a twin-screw extruder, and alkali-free glass fiber is added in proportion to the side feed. Under the conveying and shearing action of the twin-screw extruder, the mixed material is fully melted and plasticized, kneaded and mixed, extruded through a die head, stretched, cooled, pelletized, and dried to prepare a PBT / recycled PET composite material; wherein the feed rate of the twin-screw extruder is 450-800 kg / hour; the temperatures of each section of the screw of the twin-screw extruder from the feed port to the die head are 230°C, 240°C, 240°C, 250°C, 260°C, 250°C, 240°C, 230°C, and 230°C, respectively; and the screw speed is 400 rpm.

[0060] Related performance test methods:

[0061] (1) Molding performance evaluation: Demolding force was measured according to Chinese patent CN202020371834.4, unit: bar.

[0062] (2) Evaluation of heat resistance: Deformation test: The obtained PBT / PET material particles were placed in an oven at 120°C for 4 hours, and then injection molded into 125×13.0×1.0 mm specimens. A 10 g weight was added to the middle of the specimens, and the specimens were placed in an oven with a span of 7 cm and a temperature of 85°C for 40 minutes. After cooling, the height from the top of the specimen to the horizontal plane was measured, which is the deformation degree (unit: mm).

[0063] (3) Tensile strength test: According to ISO 527-2, the tensile strength of injection molded tensile specimens was measured in MPa.

[0064] Table 1: Distribution ratios of each group in Examples 1-5 (by weight) and related performance test results

[0065]

[0066] Table 2: Distribution ratios of each group in Examples 6-10 (by weight) and related performance test results

[0067]

[0068] Table 3: Distribution ratios of each group in Comparative Examples 1-7 (by weight) and related performance test results

[0069]

[0070] The above results show that the PBT / recycled PET composite material of the present invention, by selecting a specific diethylaluminum hypophosphite-melamine polyphosphate-halogen-free polyaryl phosphate flame retardant system and adding a certain amount of PA10T, can effectively solve the problems of mold sticking and bursting caused by the use of recycled PET resin in the prior art during material processing and molding, and effectively improve the heat resistance and mechanical properties of the material. The obtained halogen-free flame-retardant PBT / recycled PET composite material has a demolding force of less than 110 bar, good processability, excellent heat resistance (deformation ≤3.5 mm in heat resistance testing), and high mechanical strength.

[0071] Comparative Example 1 uses a PBT resin with an excessively high intrinsic viscosity, resulting in poor material processing and moldability, with a demolding force of 157 bar.

[0072] Comparative Example 2, using a halogen-free polyaryl phosphate having a substituent on the aromatic group, has no significant effect on improving the heat resistance of the material, and instead has a negative impact on the processability.

[0073] In comparative example 3 / 4, no halogen-free polyaryl phosphate was added, and the processing and heat resistance of the material were poor; if too much halogen-free polyaryl phosphate was added, the heat resistance would be reduced.

[0074] In Comparative Example 5, the particle size of PA10T powder is not within the required range, which has no significant effect on the processing formability and heat resistance of the material and will lead to a significant decrease in tensile strength.

[0075] In comparative examples 6 / 7, without the addition of PA10T, the heat resistance and mechanical properties of the materials were poor; however, excessive addition of PA10T resulted in a significant decrease in tensile strength.

Claims

1. A PBT / recycled PET composite material, characterized in that: Calculated by weight, it includes the following components: 25-70 parts of PBT resin; Recycle 5-25 parts of PET resin; 15-35 parts of alkali-free glass fiber; 10-25 parts of diethyl aluminum hypophosphite; 1-3 parts of melamine polyphosphate; 0.5-1 part of halogen-free polyaryl phosphate; 0.3-0.5 parts of PA10T powder; Other functional processing aids 0-1 part; The average particle size of the PA10T powder is ≤10 μm; The intrinsic viscosity of the PBT resin at 25° C. is 0.7-1.0 dL / g; There is no substituent on the aromatic group of the halogen-free polyaryl phosphate; The other functional processing aids include at least one of an antioxidant or a lubricant.

2. The PBT / recycled PET composite material according to claim 1, characterized in that The intrinsic viscosity of the recycled PET resin at 25° C. is 0.65-0.8 dL / g.

3. The PBT / recycled PET composite material according to claim 1, characterized in that The recycled PET resin is derived from post-consumer waste PET bottles.

4. The PBT / recycled PET composite material according to claim 1, characterized in that The mass content of the recycled PET resin in the PBT / recycled PET composite material is 4%-30%.

5. The PBT / recycled PET composite material according to claim 1, characterized in that The halogen-free polyaryl phosphate is selected from any one or more of bisphenol A bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate) or hydroquinone bis(diphenyl phosphate).

6. The PBT / recycled PET composite material according to claim 1, characterized in that The alkali-free glass fiber has a diameter of ≤15 μm and a length of 3-5 mm.

7. The PBT / recycled PET composite material according to claim 6, characterized in that The alkali-free glass fiber has a diameter of 7-10 μm and a length of 3-4 mm.

8. The method for preparing the PBT / recycled PET composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) PBT resin and recycled PET resin are first dried and then mixed with other components except alkali-free glass fiber in a high-speed stirring mixer according to the proportion or fed separately into a premixer through a metering feeder; (2) The mixed material is fed into a twin-screw extruder, and alkali-free glass fiber is added to the side feed. Under the conveying and shearing action of the twin-screw extruder, the mixed material is fully melted and plasticized, kneaded and mixed, extruded through the die head, stretched, cooled, pelletized, and dried to prepare a PBT / recycled PET composite material.

9. Use of the PBT / recycled PET composite material according to any one of claims 1 to 7 in the field of electronics and electrical equipment.

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