A modified polycarbonate light-absorbing transparent plastic for laser welding and a preparation method thereof

Abstract

The present application relates to the technical field of laser plastic welding, and specifically discloses a modified polycarbonate light-absorbing transparent plastic for laser welding and a preparation method thereof. The modified polycarbonate light-absorbing transparent plastic for laser welding comprises the following raw materials: polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant, and antioxidant; the preparation method comprises pre-drying the polycarbonate, adding the polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant, and antioxidant into a mixer, stirring and mixing, and then extruding and granulating to obtain the obtained plastic; the present application uses polycarbonate, polyamide, and thermoplastic polyester elastomer together to produce laser welding plastics, and all of the three are thermoplastic materials with good processability, and their common use can achieve complementary characteristics, significantly improve the overall strength, toughness, thermal stability, and impact resistance of the plastic for welding, and optimize the optical properties of the plastic for welding, thereby improving the laser welding efficiency and welding quality.

Description

Technical Field

[0001] The present application relates to the technical field of laser plastic welding, and more specifically, to a modified polycarbonate light-absorbing transparent plastic for laser welding and a preparation method thereof. Background Art

[0002] Laser transmission welding plastic technology is an emerging welding technology. Compared with traditional plastic welding methods such as hot plate welding, hot air welding, electromagnetic induction welding, resistance induction welding, friction welding, ultrasonic welding and radio frequency welding, laser transmission welding has many advantages such as fast welding speed, high degree of automation, small heat affected zone, small processing stress, no contact, no residue, precision, high bonding strength, small weld deformation, energy saving, environmental protection and green. Plastic products welded by laser transmission welding are widely used in automotive parts manufacturing, medical, electronics and food packaging and other fields, and have received widespread attention at home and abroad.

[0003] Polycarbonate (PC) is a widely used high-performance engineering plastic. It is a transparent, colorless or slightly yellowish tough solid with a transparency of up to 90%, second only to polymethyl methacrylate (PMMA) and polystyrene (PS). PC has good comprehensive mechanical properties, is rigid and tough, has good light transmittance, impact resistance, dimensional stability, electrical insulation, heat resistance and non-toxicity, and can maintain high mechanical strength in a large temperature range, but has poor fatigue resistance, wear resistance and lubricity, and is prone to stress cracking. In the related art, polycarbonate is often modified by adding other resins or inorganic fillers, but PC has poor compatibility with other resins and is not easy to form a uniform blending system, which easily causes the mechanical properties and transparency of polycarbonate to decrease. In addition, polycarbonate has a low absorption rate for lasers used in laser welding, and often requires an external light absorber. Commonly used external light absorbers such as carbon black and metal particles have poor dispersibility in the polycarbonate system and poor bonding with the resin, which will affect the performance of polycarbonate plastic products, and thus affect the welding quality of polycarbonate. Based on the above statements, the present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding and a preparation method thereof. Summary of the invention

[0004] In order to solve the problems of poor dispersibility of existing external light absorbers in polycarbonate systems and poor bonding with resins, which affect the welding quality of polycarbonate plastics, the present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding and a preparation method thereof.

[0005] In the first aspect, the present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0006] A modified polycarbonate light-absorbing transparent plastic for laser welding comprises the following raw materials in parts by weight: 70-90 parts of polycarbonate, 18-30 parts of polyamide, 5-10 parts of thermoplastic polyester elastomer, 2-5 parts of light-absorbing slurry, 0.5-1 parts of lubricant and 0.5-1 parts of antioxidant.

[0007] Preferably, the modified polycarbonate light-absorbing transparent plastic for laser welding comprises the following raw materials in parts by weight: 75-85 parts of polycarbonate, 22-26 parts of polyamide, 6-8 parts of thermoplastic polyester elastomer, 2.5-4.5 parts of light-absorbing slurry, 0.6-0.8 parts of lubricant, and 0.6-0.8 parts of antioxidant.

[0008] Preferably, the modified polycarbonate light-absorbing transparent plastic for laser welding comprises the following raw materials in parts by weight: 80 parts of polycarbonate, 24 parts of polyamide, 7 parts of thermoplastic polyester elastomer, 3.5 parts of light-absorbing slurry, 0.7 parts of lubricant, and 0.7 parts of antioxidant.

[0009] Preferably, the light-absorbing slurry is obtained by mixing a light-absorbing agent, N'N-dimethylformamide and polyvinyl pyrrolidone and then dispersing the mixture by ultrasonication.

[0010] Preferably, the mass ratio of the light absorber, N'N-dimethylformamide and polyvinyl pyrrolidone is 1:1.8-2.2:0.1-0.2.

[0011] Preferably, the ultrasonic power is 500-600W, and the ultrasonic time is 1-2h.

[0012] Preferably, the lubricant is at least one of pentaerythritol stearate, zinc stearate and calcium stearate.

[0013] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0014] In the second aspect, the present application provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0015] A method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, specifically comprising the following preparation steps:

[0016] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0017] S2. After pre-drying the polycarbonate, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, stir and mix, and then extrude and granulate to obtain the desired modified polycarbonate light-absorbing transparent plastic for laser welding.

[0018] In summary, this application has the following beneficial effects:

[0019] In this application, polycarbonate, polyamide and thermoplastic polyester elastomer are used together to produce laser welding plastics. All three are thermoplastic materials with good processability. The use of the three together can achieve complementary properties, significantly improve the overall strength, toughness, thermal stability and impact resistance of the welding plastic, and optimize the optical properties of the welding plastic; thereby making it easier to manufacture welding parts with complex shapes and improving laser welding efficiency and welding quality.

[0020] This application selects a combination of carbon nanotubes, nano-barium titanate and nano-silver as light absorbers. Carbon nanotubes, nano-barium titanate and nano-silver have different optical properties respectively. In addition, carbon nanotubes have high electrical and thermal conductivity at the nanoscale. During the welding process, they can transfer energy to the welding area more effectively to achieve local heating and melting. The combination of the three helps to convert laser energy into thermal energy, enhance the absorption capacity of lasers in different wavelength ranges, improve light absorption efficiency, and promote the welding process; at the same time, reduce the amount of light absorber added, thereby reducing costs.

[0021] The present application can more accurately control the amount of light absorber added by pre-preparing the light absorber into a light absorbent slurry and then adding it to the polycarbonate system, which helps to achieve uniform and stable dispersion of the light absorber in the polycarbonate system, prevent precipitation or aggregation of the light absorber components, and thus ensure that the light absorber is fully utilized, thereby improving laser welding efficiency. DETAILED DESCRIPTION

[0022] The present application is further described in detail below with reference to the embodiments.

[0023] The raw materials selected in the embodiment are as follows: polycarbonate is bisphenol A type aromatic polycarbonate with a weight average molecular weight of 21500, 1300-10NP, LG Chemical; polyamide viscosity 90-180 / mPa·s (25°C), HY-388, Anhui Hongtai New Materials Co., Ltd.; thermoplastic polyester elastomer KP3355, Kelon Chemical; nano-barium titanate content ≥99.9%, average particle size 100nm; nano-silver purity ≥99.9%, average particle size 20nm; carbon nanotubes are multi-walled carbon nanotubes with a purity ≥95%, a length of 20-50um, and a diameter of 8-14nm.

[0024] Example 1

[0025] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0026] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 70 parts of polycarbonate, 18 parts of polyamide, 5 parts of thermoplastic polyester elastomer, 2 parts of light-absorbing slurry, 0.5 parts of lubricant, and 0.5 parts of antioxidant;

[0027] The light-absorbing slurry is prepared by the following method:

[0028] A1, mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.4:0.1 to obtain a light absorber;

[0029] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:1.8:0.1, controlling the ultrasonic power to 500 W and the ultrasonic time to 2 h, dispersed to obtain a light absorbing slurry;

[0030] The lubricant is pentaerythritol stearate;

[0031] The antioxidant is antioxidant 1010.

[0032] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0033] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0034] S2. Pre-dry the polycarbonate at 95°C for 2h, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 700r / min, and the mixing temperature to 195°C. After stirring and mixing for 20min, add it into a twin-screw extruder, extrude and granulate it at 150°C to obtain the modified polycarbonate light-absorbing transparent plastic for laser welding.

[0035] Example 2

[0036] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0037] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 75 parts of polycarbonate, 22 parts of polyamide, 6 parts of thermoplastic polyester elastomer, 2.5 parts of light-absorbing slurry, 0.6 parts of lubricant, and 0.6 parts of antioxidant;

[0038] The light-absorbing slurry is prepared by the following method:

[0039] A1, mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.4:0.3 to obtain a light absorber;

[0040] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:1.8:0.2, controlling the ultrasonic power to 520 W and the ultrasonic time to 1.8 h, dispersed to obtain a light absorbing slurry;

[0041] The lubricant is zinc stearate;

[0042] The antioxidant is antioxidant 1076.

[0043] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0044] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0045] S2. Pre-dry the polycarbonate at 100°C for 4.5 hours, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 800r / min, and the mixing temperature to 190°C. After stirring and mixing for 15 minutes, add it into a twin-screw extruder, extrude and granulate it at 160°C to obtain the modified polycarbonate light-absorbing transparent plastic for laser welding.

[0046] Example 3

[0047] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0048] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 80 parts of polycarbonate, 24 parts of polyamide, 7 parts of thermoplastic polyester elastomer, 3.5 parts of light-absorbing slurry, 0.7 parts of lubricant, and 0.7 parts of antioxidant;

[0049] The light-absorbing slurry is prepared by the following method:

[0050] A1, mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.5:0.2 to obtain a light absorber;

[0051] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:2:0.15, controlling the ultrasonic power to 550 W and the ultrasonic time to 1.5 h, disperse and prepare a light absorbing slurry;

[0052] The lubricant is calcium stearate;

[0053] The antioxidant is antioxidant 168.

[0054] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0055] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0056] S2. Pre-dry the polycarbonate at 105°C for 3.5 hours, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 850r / min, and the mixing temperature to 185°C. After stirring and mixing for 20 minutes, add it into a twin-screw extruder, extrude and granulate it at 170°C to obtain the required modified polycarbonate light-absorbing transparent plastic for laser welding.

[0057] Example 4

[0058] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0059] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 85 parts of polycarbonate, 26 parts of polyamide, 8 parts of thermoplastic polyester elastomer, 4.5 parts of light-absorbing slurry, 0.8 parts of lubricant, and 0.8 parts of antioxidant;

[0060] The light-absorbing slurry is prepared by the following method:

[0061] A1, mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.6:0.1 to obtain a light absorber;

[0062] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:2.2:0.1, controlling the ultrasonic power to 580 W and the ultrasonic time to 1.2 h, dispersed to obtain a light absorbing slurry;

[0063] The lubricant is pentaerythritol stearate;

[0064] The antioxidant is antioxidant 1010.

[0065] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0066] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0067] S2. Pre-dry the polycarbonate at 110°C for 2.5h, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 900r / min, and the mixing temperature to 180°C. After stirring and mixing for 25min, add it into a twin-screw extruder, extrude and granulate it at 190°C to obtain the modified polycarbonate light-absorbing transparent plastic for laser welding.

[0068] Example 5

[0069] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0070] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 90 parts of polycarbonate, 30 parts of polyamide, 10 parts of thermoplastic polyester elastomer, 5 parts of light-absorbing slurry, 1 part of lubricant, and 1 part of antioxidant;

[0071] The light-absorbing slurry is prepared by the following method:

[0072] A1, mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.6:0.3 to obtain a light absorber;

[0073] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:2.2:0.2, controlling the ultrasonic power to 600 W and the ultrasonic time to 1 h, disperse and prepare a light absorbing slurry;

[0074] The lubricant is pentaerythritol stearate;

[0075] The antioxidant is antioxidant 1010.

[0076] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0077] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0078] S2. Pre-dry the polycarbonate at 115°C for 2h, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 1000r / min, and the mixing temperature to 175°C. After stirring and mixing for 18min, add it into a twin-screw extruder, extrude and granulate it at 200°C to obtain the required modified polycarbonate light-absorbing transparent plastic for laser welding.

[0079] Comparative Example 1

[0080] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0081] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 70 parts of polycarbonate, 23 parts of polyamide, 2 parts of light-absorbing slurry, 0.5 parts of lubricant, and 0.5 parts of antioxidant;

[0082] The light-absorbing slurry is prepared by the following method:

[0083] A1, mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.4:0.1 to obtain a light absorber;

[0084] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:1.8:0.1, controlling the ultrasonic power to 500 W and the ultrasonic time to 2 h, dispersed to obtain a light absorbing slurry;

[0085] The lubricant is pentaerythritol stearate;

[0086] The antioxidant is antioxidant 1010.

[0087] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0088] S1. Weigh polycarbonate, polyamide, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0089] S2. Pre-dry the polycarbonate at 95°C for 2h, add it into a mixer together with polyamide light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 700r / min, and the mixing temperature to 195°C. After stirring and mixing for 20min, add it into a twin-screw extruder, extrude and granulate it at 150°C to obtain the required modified polycarbonate light-absorbing transparent plastic for laser welding.

[0090] Comparative Example 2

[0091] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0092] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 93 parts of polycarbonate, 2 parts of light-absorbing slurry, 0.5 parts of lubricant, and 0.5 parts of antioxidant;

[0093] The light-absorbing slurry is prepared by the following method:

[0094] A1, mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.4:0.1 to obtain a light absorber;

[0095] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:1.8:0.1, controlling the ultrasonic power to 500 W and the ultrasonic time to 2 h, dispersed to obtain a light absorbing slurry;

[0096] The lubricant is pentaerythritol stearate;

[0097] The antioxidant is antioxidant 1010.

[0098] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0099] S1. Weigh polycarbonate, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0100] S2. Pre-dry the polycarbonate at 95°C for 2h, add it into a mixer together with the light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 700r / min, and the mixing temperature to 195°C. After stirring and mixing for 20min, add it into a twin-screw extruder, extrude and granulate it at 150°C to obtain the modified polycarbonate light-absorbing transparent plastic for laser welding.

[0101] Comparative Example 3

[0102] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0103] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 70 parts of polycarbonate, 18 parts of polyamide, 5 parts of thermoplastic polyester elastomer, 2 parts of light absorbent, 0.5 parts of lubricant, and 0.5 parts of antioxidant;

[0104] The light absorber is prepared by mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.4:0.1;

[0105] The lubricant is pentaerythritol stearate;

[0106] The antioxidant is antioxidant 1010.

[0107] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0108] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light absorber, lubricant and antioxidant by weight for later use;

[0109] S2. Pre-dry the polycarbonate at 95°C for 2h, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light absorber, lubricant and antioxidant, control the stirring speed to 700r / min, and the mixing temperature to 195°C. After stirring and mixing for 20min, add it into a twin-screw extruder, extrude and granulate it at 150°C to obtain the modified polycarbonate light-absorbing transparent plastic for laser welding.

[0110] Comparative Example 4

[0111] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0112] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 70 parts of polycarbonate, 18 parts of polyamide, 5 parts of thermoplastic polyester elastomer, 0.7 parts of light absorber, 0.5 parts of lubricant, and 0.5 parts of antioxidant;

[0113] The light absorber is prepared by mixing carbon nanotubes, nano-barium titanate and nano-silver in a mass ratio of 1:0.4:0.1;

[0114] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:1.8:0.1, controlling the ultrasonic power to 500 W and the ultrasonic time to 2 h, dispersed to obtain a light absorbing slurry;

[0115] The lubricant is pentaerythritol stearate;

[0116] The antioxidant is antioxidant 1010.

[0117] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0118] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light absorber, lubricant and antioxidant by weight for later use;

[0119] S2. Pre-dry the polycarbonate at 95°C for 2h, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light absorber, lubricant and antioxidant, control the stirring speed to 700r / min, and the mixing temperature to 195°C. After stirring and mixing for 20min, add it into a twin-screw extruder, extrude and granulate it at 150°C to obtain the modified polycarbonate light-absorbing transparent plastic for laser welding.

[0120] Comparative Example 5

[0121] The present application provides a modified polycarbonate light-absorbing transparent plastic for laser welding, which adopts the following technical solution:

[0122] A modified polycarbonate light-absorbing transparent plastic for laser welding, comprising the following raw materials in parts by weight: 70 parts of polycarbonate, 18 parts of polyamide, 5 parts of thermoplastic polyester elastomer, 2 parts of light-absorbing slurry, 0.5 parts of lubricant, and 0.5 parts of antioxidant;

[0123] The light-absorbing slurry is prepared by the following method:

[0124] A1. Mix carbon nanotubes and nano-barium titanate in a mass ratio of 1:0.5 to obtain a light absorber;

[0125] A2, after mixing the light absorbent, N'N-dimethylformamide and polyvinyl pyrrolidone in a mass ratio of 1:1.8:0.1, controlling the ultrasonic power to 500 W and the ultrasonic time to 2 h, dispersed to obtain a light absorbing slurry;

[0126] The lubricant is pentaerythritol stearate;

[0127] The antioxidant is antioxidant 1010.

[0128] The present application also provides a method for preparing a modified polycarbonate light-absorbing transparent plastic for laser welding, which specifically comprises the following preparation steps:

[0129] S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use;

[0130] S2. Pre-dry the polycarbonate at 95°C for 2h, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, control the stirring speed to 700r / min, and the mixing temperature to 195°C. After stirring and mixing for 20min, add it into a twin-screw extruder, extrude and granulate it at 150°C to obtain the modified polycarbonate light-absorbing transparent plastic for laser welding.

[0131] Performance Testing

[0132] The modified polycarbonate light-absorbing transparent plastic particles for laser welding prepared in Examples 1-5 of the present application and Comparative Examples 1-5 were injection molded into 100mm*100mm*2mm high-gloss plates under the same injection molding process conditions. The near-infrared projection and reflection data were collected at 960nm by a spectrophotometer, and the absorptivity = 100% - transmittance - reflectivity.

[0133] The injection-molded high-gloss plate and the transparent PMMA plate were placed alternately and irradiated with a semiconductor laser (960nm) with a beam diameter of 2mm. The surface state of the sample after welding was compared by controlling the laser intensity to 40W and the welding speed to 40mm / s. The laser welded sample was sawed into strips with a width of 10mm, and the tensile shear strength was measured with a tensile testing machine. The welding strength was calculated based on the tensile shear strength. The welding strength is tensile strength / (width of the weld*length of the weld). The results are shown in Table 1 below:

[0134]

[0135]

[0136] It can be seen from the data shown in Table 1 that the modified polycarbonate light-absorbing transparent plastic for laser welding prepared in Examples 1-5 of the present application has high laser welding efficiency, high welding quality, high light absorption efficiency and excellent comprehensive performance.

[0137] It can be seen from the examples and comparative examples 1-2 that in a polycarbonate system, compounding and adding polyamide and thermoplastic polyester elastomer can significantly improve the comprehensive performance of welding plastics.

[0138] It can be seen from Example 1 and Comparative Examples 3-4 that making the conductive agent into a conductive slurry and then adding it to the polycarbonate system helps to achieve uniform and stable dispersion of the light absorber in the polycarbonate system, prevent precipitation or aggregation of the light absorber components, and thus ensure that the light absorber is fully utilized, thereby improving laser welding efficiency.

[0139] It can be seen from Example 1 and Comparative Example 5 that the use of a composite of carbon nanotubes, nano-barium titanate and nano-silver as a light absorber can significantly improve the light absorption efficiency and promote the welding process.

[0140] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A modified polycarbonate light-absorbing transparent plastic for laser welding, characterized in that: The invention comprises the following raw materials in parts by weight: 70-90 parts of polycarbonate, 18-30 parts of polyamide, 5-10 parts of thermoplastic polyester elastomer, 2-5 parts of light-absorbing slurry, 0.5-1 parts of lubricant and 0.5-1 parts of antioxidant; The light-absorbing slurry is obtained by mixing a light absorber with N'N-dimethylformamide and polyvinyl pyrrolidone and then ultrasonically dispersing the mixture; the light absorber comprises carbon nanotubes, nano barium titanate and nano silver in a mass ratio of 1:0.4-0.6:0.1-0.3; the mass ratio of the light absorber, N'N-dimethylformamide and polyvinyl pyrrolidone is 1:1.8-2.2:0.1-0.

2.

2. The modified polycarbonate light-absorbing transparent plastic for laser welding according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 75-85 parts of polycarbonate, 22-26 parts of polyamide, 6-8 parts of thermoplastic polyester elastomer, 2.5-4.5 parts of light-absorbing slurry, 0.6-0.8 parts of lubricant and 0.6-0.8 parts of antioxidant.

3. The modified polycarbonate light-absorbing transparent plastic for laser welding according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 80 parts of polycarbonate, 24 parts of polyamide, 7 parts of thermoplastic polyester elastomer, 3.5 parts of light-absorbing slurry, 0.7 parts of lubricant and 0.7 parts of antioxidant.

4. The modified polycarbonate light-absorbing transparent plastic for laser welding according to claim 1, characterized in that: The ultrasonic power is 500-600W, and the ultrasonic time is 1-2h.

5. The modified polycarbonate light-absorbing transparent plastic for laser welding according to claim 1, characterized in that: The lubricant is at least one of pentaerythritol stearate, zinc stearate and calcium stearate.

6. The modified polycarbonate light-absorbing transparent plastic for laser welding according to claim 1, characterized in that: The antioxidant is at least one of antioxidant 1010 , antioxidant 1076 , and antioxidant 168 .

7. A method for preparing the modified polycarbonate light-absorbing transparent plastic for laser welding according to any one of claims 1 to 6, characterized in that: The specific preparation steps include: S1. Weigh polycarbonate, polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant by weight for later use; S2. After pre-drying the polycarbonate, add it into a mixer together with polyamide, thermoplastic polyester elastomer, light-absorbing slurry, lubricant and antioxidant, stir and mix, and then extrude and granulate to obtain the desired modified polycarbonate light-absorbing transparent plastic for laser welding.

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