Laser etching master batch suitable for high-light-transmittance polypropylene material and preparation method of laser etching master batch

Abstract

The invention relates to the technical field of polypropylene composite materials, and particularly discloses a laser etching master batch suitable for a high-transmittance polypropylene material and a preparation method of the laser etching master batch. The material is composed of the following raw materials in parts by weight: 5-25 wt% of titanium dioxide; 1-5 wt% of a rare earth oxide; 0.5 to 4 wt% of an amorphous alpha-olefin copolymer; 0.1-2wt% of other auxiliary agents and the balance of polypropylene. Based on the problem that the light-transmitting PP material is not easy to be subjected to laser etching, special titanium dioxide and rare earth oxide are selected to continuously absorb heat generated in the laser etching process, so that the high-light-transmitting PP material is endowed with laser etching performance and various laser etching effects, and meanwhile, the light-transmitting PP material is ensured to have a good light-transmitting effect.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a laser engraving masterbatch suitable for high-light-transmittance polypropylene material. Background Art

[0002] Polypropylene (PP) has been widely used in the fields of automobiles, home appliances, medical devices, daily necessities, etc., especially in automotive parts, such as automobile bumpers, dashboards, door panels, pillars, fenders, etc., due to its simple polymerization process, non-toxic, odorless, tasteless, strong chemical stability, acid and alkali resistance, low density and light weight, and good thermoplastic processing performance. With the development of new energy vehicles in recent years, many bold, avant-garde, and subversive design elements have been introduced, and the requirements for intelligence and technology are increasing. Compared with traditional parts, adding optical elements to interior and exterior decoration can not only play a basic lighting and decorative role, but also play a role in brand building, driving assistance, safety reminders, etc., and can add new functions such as light language interaction and human-vehicle interaction to enhance product competitiveness. Therefore, some automotive parts are required to have a certain degree of light transmittance.

[0003] At present, the light-transmitting parts of automobile interior and exterior decoration are mainly sprayed with paint on PP substrate to show a better appearance effect, and at the same time, laser engraving can show a special light appearance effect, giving consumers a strong visual sensory experience. Laser engraving refers to laser engraving, which uses the light energy of the laser beam to cause chemical and physical changes in the surface material to carve out the expected traces, or ablates part of the material through light energy to show the required etched graphics and text. It is a surface treatment process, similar to screen printing and pad printing, which can achieve text or pattern effects on the product, but laser engraving has the advantages of fast marking speed, beautiful patterns, high resolution and good accuracy.

[0004] Using spray paint laser engraving technology to perform large-area laser engraving color separation on automotive parts is a new application mode. However, the paint spraying process is complicated, the environmental pollution is large, and the technical difficulty is high. More and more spray paints are gradually replaced by spray-free systems. By adding laser engraving additive masterbatch, various color separation effects such as black engraving white, white engraving black, and white engraving blue can be achieved. At present, the laser engraving additives on the market are added to the light-transmitting PP system, which seriously affects the light transmittance of materials and parts. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a laser engraving masterbatch suitable for high light transmittance polypropylene material and a preparation method thereof.

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

[0007] The laser engraving masterbatch suitable for high light transmittance polypropylene material of the present invention is composed of the following raw materials in parts by weight:

[0008] Titanium dioxide: 5-25wt%;

[0009] Rare earth oxides 1-5wt%;

[0010] Amorphous α-olefin copolymer 0.5-4wt%;

[0011] Additives: 0.1-2wt%;

[0012] Polypropylene: remaining components.

[0013] The titanium dioxide is rutile nano titanium dioxide, and the grain size is 1-50nm.

[0014] The rare earth oxide is one of lanthanum oxide, cerium oxide, praseodymium oxide, etc., and the particle size is ≤300m.

[0015] The amorphous α-olefin copolymer has a melt viscosity of ≤9000 mPa s at 190°C.

[0016] The auxiliary agent is mainly a combination of an antioxidant and a light stabilizer, wherein the antioxidant is mainly a combination of three kinds of hindered phenol, phosphite and thiosulfate; and the light stabilizer is a combination of a hindered amine and an ultraviolet absorber.

[0017] The polypropylene resin is a random polypropylene resin with a melt flow rate of 2-30 g / 10 min under the test conditions of 230° C. @ 2.16 kg, a visible light transmittance (3.2 mm) of ≥ 65%, and a haze (3.2 mm) of ≥ 20%.

[0018] The above-mentioned method for preparing laser engraving masterbatch suitable for high light transmittance polypropylene material has the following production steps:

[0019] (1) dissolving titanium dioxide in a strong acid and weak base salt at a mass ratio of 1:10 to 1:40, adding a corresponding proportion of rare earth oxide after ultrasonic treatment for 0.5 to 1 h, and ultrasonic treatment again for 1 to 2 h;

[0020] (2) After the ultrasonic treatment, the mixture was added to a high-speed centrifuge for centrifugal drying. After the centrifugation, deionized water was added for multiple washings. Each washing time was about 10 to 30 minutes. Generally, the mixture was washed 2 to 3 times. Finally, the pH value of the deionized water was ensured to be close to 7. After the washing, the mixture was vacuum dried.

[0021] (3) The dried powder, polypropylene, amorphous α-olefin copolymer and additives are added to a high-speed mixer according to the corresponding weight ratio and mixed evenly, and then added to the main feed port of a twin-screw extruder for melt mixing; the extrusion temperature is 200-230°C, and the screw speed is 200-600rpm. After melt extrusion, cooling, granulation and homogenization, a laser engraving masterbatch suitable for high-transmittance polypropylene material is obtained.

[0022] The present invention uses ultrafine nano-scale titanium dioxide, which can significantly absorb laser energy without affecting the light transmittance of the light-transmitting PP material. Rare earth oxides also have a strong absorption capacity for lasers, and using different rare earth oxides can change the hue after laser engraving, approaching the effect of spray paint laser engraving, optimizing the production process, and reducing environmental pollution and costs.

[0023] Amorphous α-olefin copolymers have good lubrication and processing characteristics. Compared with traditional stearates, this copolymer has a larger molecular weight and is less likely to have sticky defects. At the same time, this copolymer has very excellent light transmittance, PP compatibility and lubrication effect, and will not affect the light transmittance of translucent PP materials. It is suitable for use in high-transmittance PP systems. DETAILED DESCRIPTION

[0024] The present invention can be further described by the following preferred embodiments, but these embodiments are only for illustration and do not limit the scope of the present invention.

[0025] In the composite material formula of the embodiment and the comparative example, the polypropylene resin in the laser engraving masterbatch used for the high light transmittance polypropylene material is provided by Shandong Jingbo Polyolefin New Materials Co., Ltd., with a trade name of RP340R, and a melt flow rate of 28g / 10min at 2.16kg@230℃. Titanium dioxide is provided by Anshan Iron and Steel Group Vanadium Titanium (Steel) Research Institute, with a trade name of PGNA-10, and a grain size of about 9nm. Rare earth oxide is provided by Ganzhou Qiming New Materials Co., Ltd., with a specific component of lanthanum oxide and a particle size of about 40nm. Amorphous α-olefin copolymer is provided by Evonik Degussa (China) Co., Ltd., with a trade name of VESTOPLAST 708. Antioxidant is provided by Tianjin Lianlong New Materials Co., Ltd., with trade names of Irganox3114, Irganox 168 and Negonox DSTP, with a ratio of 2:1:1; light stabilizer is provided by Xinxiu Chemical, with a trade name of 5229; the addition ratio of antioxidant and light stabilizer is; 2:1. The commercially available laser engraving additive masterbatch in the comparative example is provided by Guangdong Dazhan Jiyuan New Material Technology Co., Ltd. The conventional titanium dioxide in the comparative sample is R-2219 provided by China National Nuclear Titanium Dioxide Co., Ltd., with a particle size of 0.3 μm.

[0026] Examples A1-A7 and comparative examples B1-B3 are for the preparation of high-transmittance PP laser engraving masterbatch.

[0027] According to the ratio in Table 1, titanium dioxide was dissolved in an ammonium sulfate solution at a mass ratio of 1:20, and rare earth oxides in a corresponding proportion were added after ultrasonic treatment for 0.5 to 1 h, and ultrasonic treatment was repeated for 1 to 2 h;

[0028] After the ultrasonic treatment, add it to a high-speed centrifuge for centrifugal drying. After the centrifugation, add deionized water for multiple washings. Each washing time is about 10 to 30 minutes. Generally, wash 2 to 3 times to ensure that the pH value in the deionized water is close to 7. After washing, vacuum drying is performed.

[0029] The dried powder, polypropylene, amorphous α-olefin copolymer and additives are added in a high-speed mixer according to the corresponding weight ratio and mixed evenly, and then added to the main feed port of the twin-screw extruder for melt mixing; the extrusion temperature is 200-230°C, and the screw speed is 200N600rpm. After melt extrusion, cooling, granulation and homogenization, laser engraving masterbatch suitable for high-transmittance polypropylene materials is obtained.

[0030] Table 1 Distribution ratio of each group of Examples A1 to A7 and Comparative Examples B1-B3 (parts by weight)

[0031]

[0032] According to the ratio in Table 2, polypropylene and the laser engraving masterbatch shown in Table 1 were melt mixed in a twin-screw extruder with an aspect ratio of 40-52:1, extruded into granules, and the extrusion temperature was between 160-230°C. The obtained material was injection molded into a 3mm sample. After injection molding, the sample was placed on a laser engraving machine for laser engraving, and the transmittance of the non-laser engraving area was tested. The specific transmittance was tested according to the GB / T2410 standard. In addition, the color effect after laser engraving was mainly tested by using a CM-2500C spectrophotometer to test the L value of the laser engraving area. The relevant results are shown in Table 3.

[0033] Table 2: Formulas of components of Examples 1 to 7 and Comparative Examples 1 to 5.

[0034]

[0035] Table 3: Comparison of optical properties and laser engraving effects of Examples 1 to 7 and Comparative Examples 1 to 5

[0036]

[0037] From the results of the transmittance and laser engraving color development of Example 1, Comparative Examples 1-2, and Comparative Examples 4-5, it can be seen that the laser engraving masterbatch prepared with titanium dioxide and rare earth metal oxide of special particle size and specification has no significant reduction in the transmittance of PP material, and gives the translucent PP material better laser engraving performance. Conventional carbon dioxide and laser engraving masterbatch have a greater impact on the transmittance of PP material. From the results of the transmittance and laser engraving color development of Examples 1-3, it can be seen that with the increase of the content of titanium dioxide, the transmittance decreases slightly, but the decrease is not obvious, and the L value after laser engraving is significantly reduced. The lower the L value, the higher the blackness, which means that the color difference effect of laser engraving is more obvious, and the appearance effect is better in actual use. From the results of the transmittance and laser engraving color development of Examples 2, 4, and 5, it can be seen that the transmittance has been slightly reduced with the increase of rare earth content, but the color development effect after laser engraving is better. The light transmittance and laser engraving color development results of Examples 4, 6 and 7 show that the addition of amorphous α-olefin copolymers can improve the dispersion of titanium dioxide nanoparticles and rare earth oxides, thereby reducing the impact on the light transmittance of the PP material. At the same time, the copolymer has no effect on the laser engraving effect. Therefore, the addition of amorphous α-olefin copolymers is helpful in preparing the laser engraving masterbatch of this high-transmittance PP material.

[0038] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined by the claims.

Claims

1. A laser engraving masterbatch suitable for high light transmittance polypropylene material, characterized in that: It is composed of the following raw materials in parts by weight: Titanium dioxide: 5-25wt%; Rare earth oxides 1-5wt%; Amorphous α-olefin copolymer 0.5-4wt%; Additives: 0.1-2wt%; Polypropylene: remaining components.

2. The laser engraving masterbatch suitable for high light transmittance polypropylene material according to claim 1, characterized in that: The titanium dioxide is rutile nano-titanium dioxide, and the grain size is 1 to 100 nm.

3. The laser engraving masterbatch suitable for high light transmittance polypropylene material according to claim 1, characterized in that: The rare earth oxide is one of lanthanum oxide, cerium oxide and praseodymium oxide, and the particle size is ≤500nm.

4. The laser engraving masterbatch suitable for high light transmittance polypropylene material according to claim 1, characterized in that: Amorphous α-olefin copolymer, melt viscosity ≤10000mPa s at 190°C.

5. The laser engraving masterbatch suitable for high light transmittance polypropylene material and the preparation method thereof according to claim 1, characterized in that: The auxiliary agent is a combination of an antioxidant and a light stabilizer, wherein the antioxidant is a combination of several kinds of hindered phenol, phosphite and thiosulfate; and the light stabilizer is one kind or a combination of several kinds of hindered amine and ultraviolet absorber.

6. The laser engraving masterbatch suitable for high light transmittance polypropylene material according to claim 1, characterized in that: The polypropylene resin is a random polypropylene resin, with a melt flow rate of 0.5-30 g / 10 min under the test conditions of 230° C.@2.16 kg, a visible light transmittance (3.2 mm) ≥60%, and a haze (3.2 mm) ≥10%.

7. The method for preparing laser engraving masterbatch suitable for high light transmittance polypropylene material according to any one of claims 1 to 6, characterized in that: The production steps are as follows: (1) dissolving titanium dioxide in a strong acid and weak base salt at a mass ratio of 1:10 to 1:40, adding a corresponding proportion of rare earth oxide after ultrasonic treatment for 0.5 to 1 h, and ultrasonic treatment again for 1 to 2 h; (2) After the ultrasonic treatment, the mixture was added to a high-speed centrifuge for centrifugal drying. After the centrifugation, deionized water was added for multiple washings. Each washing time was about 10 to 30 minutes. Generally, the mixture was washed 2 to 3 times. Finally, the pH value of the deionized water was ensured to be close to 7. After the washing, the mixture was vacuum dried. (3) adding the dried powder, polypropylene, amorphous α-olefin copolymer, and additives according to a corresponding weight ratio into a high-speed mixer and mixing them evenly, and then adding them into the main feed port of a twin-screw extruder for melt mixing; the extrusion temperature is 200-230° C., and the screw speed is 200-600 rpm; after melt extrusion, cooling, granulation, and homogenization, a laser engraving masterbatch suitable for high-transmittance polypropylene material is obtained.

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