Spraying-free scattering point for polycarbonate material, preparation method of spraying-free scattering point and spraying-free polycarbonate material with scattering point effect

Abstract

The invention discloses a spraying-free scattering point for a polycarbonate material, a preparation method and a spraying-free polycarbonate material with a scattering point effect. The spraying-free scattering point is prepared from the polytetrafluoroethylene resin, the antioxidant, the lubricant, the weather-resistant agent and the toner, so that the problems of particle size reduction, unobvious visual effect and the like of scattering point spraying-free spraying under harsh process conditions of a polycarbonate material are solved. According to the spraying-free polycarbonate material with the scattering point effect, the spraying-free scattering points are introduced, so that an obvious surface effect can be realized in high-temperature and high-shear extrusion and molding of the polycarbonate material, and good mechanical properties can be kept; the method has the advantages of high stability of extrusion and molding processes, low production cost and high mass production amplification. The prepared spraying-free polycarbonate material with the spot scattering effect can be applied to the fields of automotive upholsteries, mobile phone jackets, earphone accessories, household appliance shells and the like with strict requirements on appearance, production process and performance.

Description

Technical Field

[0001] This invention relates to the field of paint-free plastics, specifically to a paint-free spraying method for polycarbonate materials and a method for preparing a paint-free polycarbonate material with a spraying effect, and a method for preparing such a material. Background Technology

[0002] In recent years, polycarbonate resins have been increasingly widely used in the automotive, home appliance, and consumer electronics industries. The speckled effect, with its unique and aesthetically pleasing appearance, has gained popularity among consumers and end-product manufacturers. To create a natural, random, and particle-size-variant effect, spraying is often used. However, spraying is complex, time-consuming, costly, environmentally polluting, has a high defect rate, and the paint surface is easily damaged and peels off. Spray-free materials, on the other hand, are produced through a one-time injection molding process, achieving both aesthetic appeal and performance. They require no post-spraying treatment, have a short production cycle, are energy-efficient and environmentally friendly, reduce processing and raw material costs, and impart an aesthetic texture to the product surface, meeting the personalized requirements of consumers and different application scenarios. These advantages have led to their gradual replacement of spraying processes in various fields.

[0003] Currently, there is a growing demand for paint-free polycarbonate materials with a speckled effect in applications such as mobile phone cases, earphone charging cases, and automotive interior parts. However, the raw materials for these speckled polycarbonate materials typically include potassium feldspar fragments, aluminum foil, glitter powder, and pearlescent powder. Due to their poor shear resistance, the original size and shape of the speckled material are often broken into fragments during extrusion, affecting aesthetics. Furthermore, the high surface hardness of these minerals makes them prone to scratching the surface during resin melt flow, preventing their application in glossy products. In addition, PET resin speckling suffers from limitations due to its inability to withstand temperatures above 280℃~300℃, restricting injection molding and extrusion processes, resulting in a narrow process window and a lack of mass production stability. The addition of certain additives can also lead to polycarbonate resin degradation, affecting mechanical properties and failing to meet product quality requirements. These drawbacks significantly limit its practical application and hinder mass production.

[0004] Chinese patent CN116253980A discloses a halogen-free flame-retardant PC / ABS material with a non-spraying and spot-spraying effect for consumer recycling and its preparation method. Due to its poor heat resistance, polycarbonate material is limited to injection molding products at 300℃. This method of direct extrusion granulation will result in reduced particle size of the spot-spraying particles, an indistinct visual spot-spraying effect, and reduced material performance, which cannot meet the product quality requirements and the needs of consumers and end-consumer products.

[0005] Therefore, a spray-free coating method for polycarbonate has been developed, which also has properties such as high temperature resistance and shear resistance, and has good economic value and application prospects. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, the present invention aims to provide a non-spraying dotting method for polycarbonate materials. The dotting is prepared using polytetrafluoroethylene, color powder, and other raw materials, solving the problems of particle size reduction and unclear visual effect that occur under the harsh processing conditions of polycarbonate materials in non-spraying applications.

[0007] The present invention also aims to provide a spray-free polycarbonate material with a dotting effect and its preparation method. The material incorporates the aforementioned spray-free dotting technique, enabling it to meet the stringent process requirements of high-temperature, high-shear polycarbonate materials, achieving stable mass production. It provides a polycarbonate resin material that combines a clear, random spray-free dotting effect with excellent mechanical properties, overcoming the limitations of existing technologies in application and processing. It can be widely used in automotive interior parts, mobile phone cases, headphone accessories, and household appliance casings.

[0008] To achieve the above effects, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a spray-free application method for polycarbonate materials, comprising the following raw material composition by weight percentage:

[0010] Polytetrafluoroethylene resin: 90-95%, for example 90%, 91%, 92%, 93%, 94%, 95%, etc.

[0011] Antioxidant: 0.1%–0.5%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc.

[0012] Lubricant: 0.1%–3%, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc.

[0013] Weather resistant agent: 0.3%–5%, for example, 0.3%, 1%, 2%, 3%, 4%, 5%, etc.

[0014] Toughening agent: 1-5%, for example, 1%, 2%, 3%, 4%, 5%, etc.

[0015] Pigment: 0.2% to 2%, for example, 0.2%, 0.5%, 1%, 1.5%, 2%, etc.

[0016] In some specific embodiments, the polytetrafluoroethylene resin is at least one or more with a melting point in the range of 280 to 310°C, such as 280°C, 290°C, 300°C, 310°C, etc.

[0017] Preferably, the polytetrafluoroethylene resin has a melt index of 10-30 g / 10 min at 372°C and 5.0 kg, such as 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, etc.

[0018] More preferably, the polytetrafluoroethylene resin is at least one or more of DuPont 340, 850A, 416HP, and MP1400.

[0019] The antioxidants, lubricants, weathering agents, and toughening agents mentioned are conventional additives in the field, and those skilled in the art can select them as needed. This invention does not impose any specific limitations.

[0020] In some specific implementation schemes, the antioxidant is selected from at least one or more of phosphites, hindered amines, and high-efficiency compound antioxidants, preferably at least one or more of hindered amine 1076 and compound antioxidant (B900), wherein the effect is better when two antioxidants are combined.

[0021] In some specific embodiments, the lubricant is selected from one or more of pentaerythritol ester (PETS), ethylene bis-stearamide, and polytetrafluoroethylene modified polyethylene wax, preferably pentaerythritol ester (PETS).

[0022] In some specific implementations, the weathering agent is selected from at least one or more of high molecular weight hindered amine light stabilizers and ultraviolet absorbers, preferably at least one or more of UV944 and light stabilizer 770.

[0023] In some specific embodiments, the toughening agent is selected from at least one or more of acrylates, silicones, and methacrylate-olefin copolymers, preferably at least one or more of methacrylate-butadiene-styrene (MBS) and core-shell impact modifiers (M-732).

[0024] In some specific embodiments, the color powder is selected from at least one of organic dyes, organic pigments, and inorganic pigments, preferably at least one of the organic dyes Transparent Blue 3R, titanium dioxide CR211, and carbon black 9A32.

[0025] Secondly, the present invention provides a method for preparing the above-mentioned spray-free dotting method for polycarbonate materials. The method involves mixing the raw materials, extruding and granulating them using conventional methods to obtain a dotting base material, and then preparing the dotting base material by liquid nitrogen pulverization. Specifically, the preparation method includes the following steps:

[0026] 1) Preparation of the dotting base material: Polytetrafluoroethylene resin, antioxidant, lubricant, weathering agent, toughening agent and color powder are mixed. The mixture is extruded and granulated by an extruder to obtain the dotting base material.

[0027] 2) Preparation of the powder: Put the powder base material into a liquid nitrogen pulverizer, pulverize and sieve to obtain a powder with a mesh size of 20-100.

[0028] In some specific implementation schemes, step 1) involves mixing the materials in a high-speed mixer. The mixture is then thoroughly mixed by the low-shear screw assembly of a twin-screw extruder before extrusion granulation. Specific parameters are not particularly required; for example, the twin-screw extruder screw temperatures from the feed inlet to the die head are set to 220°C, 250°C, 265°C, 270°C, 270°C, 270°C, 280°C, and 290°C, with a rotation speed of 400 rpm and a die head pressure of less than 20 bar. This operation allows the polytetrafluoroethylene (PTFE) material to maintain good performance stability and good compatibility with polycarbonate resin.

[0029] In some specific implementations, the liquid nitrogen pulverizer described in step 2) has a pulverizing temperature of -100 to -196℃, such as -100℃, -120℃, -140℃, -160℃, -170℃, -180℃, -196℃, etc., a pulverizer speed of 5000 to 16000 r / min, such as 5000 r / min, 8000 r / min, 10000 r / min, 13000 r / min, 16000 r / min, etc., and a liquid nitrogen pressure of 0.2 to 2 MPa, such as 0.2 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, etc. A. During the crushing process, it is best to sprinkle the base material into the nut that fixes the blade in the center of the crushing chamber. Specifically, use a liquid nitrogen pump (pressurized with a foot pump) to evenly introduce liquid nitrogen into the crushing chamber. The recommended opening angle of the liquid nitrogen pump outlet valve is 30-45 degrees. Add the sprinkled base material to the nut that fixes the blade in the center of the machine. The feeding speed can be monitored by observing the ammeter (the maximum amplitude of the current pointer swing during crushing should be ≤10A). The feeding speed should be quantitative and uniform (similar to flowing water). The crushed material should be 20-100 mesh, such as 20 mesh, 40 mesh, 60 mesh, 80 mesh, 100 mesh, or any combination of any two points within this range. Using liquid nitrogen crushing to obtain the sprinkled material ensures good compatibility with polycarbonate, resulting in excellent performance; it also provides high temperature resistance and shear resistance; injection molded products are scratch-free, and the sprinkled material maintains good dimensions.

[0030] Thirdly, the present invention provides a spray-free polycarbonate material with a dotting effect, the material comprising the above-mentioned spray-free dotting method for polycarbonate materials.

[0031] In a preferred embodiment, the dotting effect spray-free polycarbonate material comprises the following raw material composition by weight percentage:

[0032] Polycarbonate resin: 80-98%, such as 80%, 84%, 88%, 92%, 96%, 98%, etc., preferably 85-97%.

[0033] Antioxidant: 0.1%–0.6%, such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, etc.

[0034] Lubricant: 0.1%–3%, for example, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc.

[0035] Weather resistant agent: 0.3%–5%, for example, 0.3%, 1%, 2%, 3%, 4%, 5%, etc.

[0036] For spray-free application of polycarbonate materials: 0.5% to 10%, such as 0.5%, 2%, 4%, 6%, 8%, 10%, etc., preferably 0.5% to 6%.

[0037] In some specific embodiments, the polycarbonate resin is at least one of the following: melt index of 10 to 30 g / 10 min at 300°C and 1.2 kg, such as 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, etc., preferably at least one of Wanhua Chemical 2350, 2220, 2100, and A1225.

[0038] The antioxidants, lubricants, and weathering agents mentioned are conventional additives in the field, and those skilled in the art can select them as needed. This invention does not impose specific limitations. For example, in some specific examples, the antioxidants used are at least one or more of phosphites, hindered amines, and high-efficiency composite antioxidants, preferably at least one or more of hindered amine 1076 and composite antioxidants (B900), and more preferably two or more. The lubricant is at least one or more of pentaerythritol ester (PETS), ethylene bis-stearamide, and polytetrafluoroethylene modified polyethylene wax. The weathering agent is one or more of high molecular weight hindered amine light stabilizers and ultraviolet absorbers.

[0039] The spray-free polycarbonate material with the dotting effect described above can be prepared by conventional extrusion and granulation methods, and this invention does not impose any specific limitations.

[0040] For example, the present invention provides a method for preparing a speckled, spray-free polycarbonate material, comprising the following steps:

[0041] Polycarbonate, antioxidants, lubricants, weathering agents, and a spray-free coating agent for polycarbonate materials are mixed in a high-speed mixer. The mixture is then extruded and granulated using a twin-screw extruder to obtain a spray-free polycarbonate material with a coating effect.

[0042] This invention also provides the application of the spray-on polycarbonate material with the dot-spray effect in the fields of 3C electronics, automotive interior parts, and home appliances, and is especially suitable for preparing products such as automotive interior parts, mobile phone cases, headphone accessories, and home appliance shells with the spray-on effect.

[0043] In application, the dot-effect, paint-free polycarbonate material is injection molded. The temperatures of each section of the injection molding machine are set sequentially as follows: 220–245°C, 250–260°C, 265–275°C, 265–275°C, 265–275°C, 265–275°C, 280–300°C, and 280–320°C. The plasticizing pressure is 2–10 MPa, and the injection pressure is 10–25 MPa for the first stage, 30–50 MPa for the second stage, and 40–60 MPa for the third stage. The holding and cooling time is 10–20 seconds. After injection molding, paint-free polycarbonate resin parts with a dot-effect can be obtained.

[0044] The dot-effect paint-free polycarbonate material of the present invention includes the above-mentioned paint-free dot-effect for polycarbonate materials. After injection molding, it can be made into paint-free appearance parts with dot-effect, and has the advantages of high temperature resistance, shear resistance, and good mechanical properties.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] This invention provides a self-made dotting technique that can achieve a noticeable dotting surface effect in polycarbonate resin under high-temperature injection molding (280℃~320℃ and above) and high-shear extrusion conditions. It is suitable for paint-free polycarbonate resin products with different surface structures, and the products are free of silver streaks and scratches. The dotting technique provided by this invention has excellent compatibility with polycarbonate resin, enabling the material to maintain good mechanical and flame-retardant properties. Furthermore, the amount and appearance of the dotting can be controlled by adjusting the dotting ratio and catering to individual consumer needs. It offers advantages such as low production cost and high scalability for mass production.

[0047] This invention provides a spray-on polycarbonate material with a dot-spray effect that can be directly injection molded, greatly reducing processing costs and offering advantages such as environmental friendliness. It has good economic value and application prospects in fields with stringent requirements for appearance and performance, and a pursuit of personalized aesthetics, such as automotive interior parts, mobile phone cases, headphone accessories, and home appliance casings. Attached Figure Description

[0048] Figure 1 This is an image showing the effect of spray-free dotting on a glossy color swatch obtained by injection molding in Example 1.

[0049] Figure 2 This is a diagram showing the effect of spraying-free dot application on a glossy color swatch obtained by injection molding as a comparative example 1. Detailed Implementation

[0050] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

[0051] Unless otherwise specified, the raw materials used in the examples can be obtained from conventional sources, as detailed in Table 1 below:

[0052] Table 1

[0053] raw material factory Brand polytetrafluoroethylene resin DuPont, USA 340, 850A, 416HP polycarbonate resin Wanhua Chemical 2350、2220 antioxidants Lianlong 1076、B900 lubricant Shandong Ruijie PETS Weathering agent Rising Star Chemistry UV-944, 770 toughening agent Japanese Bell M-732 Pigment CITIC CR211 Pigment Cabot 9A32 Pigment Lanxess Transparent Blue 3R Potassium feldspar Rongcai 8225 Pearl powder Aika C001 aluminum sheet Prosperity MD013 Flash Blue Diamond Fubo Supearl D107 Glitter powder Guansheng V5LA100

[0054] Unless otherwise specified, the other reagents, methods and equipment used in this invention are conventional reagents, methods and equipment in this technical field.

[0055] Preparation Examples 1-5: Spray-free application of polycarbonate materials (S1-S5)

[0056] 1) Preparation of the dotting base material: According to the proportions (mass percentage) in Table 2 below, add polytetrafluoroethylene resin, antioxidant, lubricant, weathering agent, toughening agent, and color powder into a high-speed mixer, mix well, and then add to a twin-screw extruder for extrusion and granulation. The screw temperature is set in sections from the feed inlet to the die head as 220℃, 250℃, 265℃, 270℃, 270℃, 270℃, 280℃, and 290℃, the speed is 400 rpm, and the die head pressure of the twin-screw extruder is less than 20 bar to obtain the dotting base material.

[0057] 2) Preparation of the powder: Use a liquid nitrogen pump (pressurized by a foot pump) to evenly introduce liquid nitrogen into the machine's grinding chamber. The recommended opening angle of the liquid nitrogen pump outlet valve is 30-45 degrees. It is best to put the powder base material into the nut that fixes the blade in the center of the machine. The feeding speed can be observed by the ammeter (the maximum swing amplitude of the current pointer during the grinding process is ≤10A). The feeding speed must be quantitative and uniform (similar to flowing water). The parameters of the liquid nitrogen pulverizer are controlled as shown in Table 2 below. The powder is ground into powders of different particle sizes and then sieved to classify them into powders with a mesh size of 20-100.

[0058] Table 2

[0059]

[0060] Comparative preparation example 1: Preparation of sprinkled spot D1

[0061] The preparation method is the same as in Example 1, except that polytetrafluoroethylene is replaced with heat-resistant polycarbonate (Covestro 2097), while other operations and conditions remain unchanged.

[0062] Comparative Preparation Example 2: Preparation of Sprinkled D2

[0063] The method is the same as in Preparation Example 1, except that in step 2), a grinder is used instead of a liquid nitrogen pulverizer, while other operations and conditions remain unchanged.

[0064] Examples 1-5: Preparation of spray-free polycarbonate materials with a dotting effect

[0065] According to the proportions (mass percentage) in Table 3 below, polycarbonate, antioxidant, lubricant, weathering agent, and the no-spray coating points (D1-D5) for polycarbonate materials are mixed evenly in a high-pressure mixer. Then, the mixture is fed into a twin-screw extruder for extrusion and granulation. The screw temperature is set in sections from the feed inlet to the die head as follows: 220℃, 250℃, 265℃, 270℃, 270℃, 270℃, 280℃, 280℃. The speed is 500 rpm, and the die head pressure of the twin-screw extruder is less than 10 bar. This produces a no-spray polycarbonate resin material with a coating effect.

[0066] Table 3

[0067]

[0068] Comparative Examples 1-7:

[0069] Referring to the method in Example 1, the difference is that the sprinkling point S1 is replaced in sequence with glitter powder V5LA100, aluminum sheet MD013, glitter blue diamond Supearl D107, pearlescent powder C001, potassium feldspar 8225, sprinkling point D1, and sprinkling point D2, while other operations and conditions remain unchanged.

[0070] The performance of parts obtained by injection molding from the dot-spraying, spray-free polycarbonate materials prepared in Examples 1-5 and Comparative Examples 1-7 was tested.

[0071] The spray-free polycarbonate materials with a dot-sprinkling effect obtained in the above embodiments and comparative examples were injection molded and subjected to high-temperature resistance tests. The specific methods are as follows: the injection molding machine head temperatures were set to 280℃, 290℃, 300℃, 310℃, and 320℃; the plasticizing pressure was 2–10 MPa; the injection pressure was 20 MPa for the first stage, 40 MPa for the second stage, and 50 MPa for the third stage; the holding pressure and cooling time was 20 seconds. All were injection molded into 90×55×3mm glossy color plates. Figure 1 The image shown is a glossy color plate prepared in Example 1. Figure 2 The glossy color swatches prepared in Comparative Example 1 are shown in Table 4. The glossy color swatches prepared in the examples and comparative examples were evaluated under D65 light, assessing their appearance at different high temperatures based on four dimensions: "no silver streaks," "few silver streaks," "many silver streaks," and "severe silver streaks."

[0072] Table 4

[0073] Injection temperature 280℃ 290℃ 300℃ 310℃ 320℃ Example 1 ○ ○ ○ ○ ○ Example 2 ○ ○ ○ ○ ○ Example 3 ○ ○ ○ ○ ○ Example 4 ○ ○ ○ ○ ○ Example 5 ○ ○ ○ ○ ○ Comparative Example 1 ○ + + +++ +++ Comparative Example 2 ○ + ++ +++ +++ Comparative Example 3 ○ + + +++ +++ Comparative Example 4 ○ + ++ +++ +++ Comparative Example 5 ○ + +++ +++ +++ Comparative Example 6 ○ ○ ○ + ++ Comparative Example 7 ○ ○ + ++ +++

[0074] *Note: No silver threads is ○, few silver threads are +, many silver threads are ++, severe silver threads are +++.

[0075] The shear resistance test was conducted on the spray-free polycarbonate materials with the above-described embodiments and comparative examples. The specific method is as follows: the screw temperature was set in sections from the feed inlet to the die head at 220℃, 250℃, 265℃, 270℃, 270℃, 270℃, 280℃, and 290℃, and the rotation speed was 500 rpm. The die head pressure of the twin-screw extruder was less than 10 bar. All materials were injection molded into 90×55×3mm glossy color plates. The surface was observed under D65 lighting. The screw shear was used to rate the size, quantity, and obviousness of the spray dots, with the best being level 5 and the worst being level 1. Level 5 indicates large and numerous spray dots or a very obvious spray dot effect; level 1 indicates that the spray dots are almost invisible or too small and too few. Comparisons are shown in Table 5.

[0076] Table 5

[0077]

[0078]

[0079] Other performance tests were conducted on the spray-effect, spray-free polycarbonate materials prepared in the above embodiments and comparative examples. The specific methods are as follows:

[0080] Melt index (PTFE): Tested according to ASTM D1238 standard, under test conditions of 372℃ / 5.0kg;

[0081] Melt index (PC): Tested according to ASTM D1238 standard, under test conditions of 300℃ / 1.2kg;

[0082] Tensile modulus: Tested according to ASTM D638 standard, test conditions 1 mm / min;

[0083] Flexural modulus: Tested according to ASTM D790 standard, under test conditions of 2 mm / min;

[0084] Notched impact strength of cantilever beam: Tested according to ISO 180 standard, under test conditions of 23℃;

[0085] Flame retardancy rating (V0 / V1 / V2 / HB): UL94-2018 test standard, test condition is 1.5mm;

[0086] The test results are shown in Table 6.

[0087] Table 6

[0088]

[0089] According to the test results in Tables 4, 5, and 6, the spray-coated polycarbonate materials of each embodiment of the present invention can all exhibit no silver streaks due to material degradation during high-temperature injection molding at 280℃-320℃. During twin-screw extrusion under shear conditions, the size, quantity, and visibility of the spray dots are all at level 4 or higher, with some embodiments reaching level 5, demonstrating a very dense and obvious spray effect. Furthermore, some preferred embodiments combine better high-temperature and shear-resistant spray-coated effects with superior mechanical and flame-retardant properties.

[0090] The above embodiments of the present invention are merely examples to clearly illustrate the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make other modifications based on the above description; it is impossible to exhaustively list all possible implementations. Any modifications, substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims.

Claims

1. A spray-free application method for polycarbonate materials, characterized in that, It contains the following raw material composition by weight percentage: Polytetrafluoroethylene resin: 90-95%, Antioxidant: 0.1-0.5%, Lubricant: 0.1-3%, Weather resistant agent: 0.3-5%, Toughening agent: 1-5%, Pigment: 0.2%–2%.

2. The spray-free application method according to claim 1, characterized in that, The polytetrafluoroethylene resin is at least one or more types with a melting point of 280 to 310°C; Preferably, the polytetrafluoroethylene resin has a melt index of 10-30 g / 10 min at 372°C and 5.0 kg. More preferably, the polytetrafluoroethylene resin is at least one or more of DuPont 340, 850A, 416HP, and MP1400.

3. The spray-free application method according to claim 1 or 2, characterized in that, The antioxidant is selected from at least one or more of phosphites, hindered amines, and high-efficiency compound antioxidants, preferably at least one or more of hindered amine 1076 and compound antioxidant B900; and / or The lubricant is selected from at least one or more of zinc stearate, ethylene bis-stearamide, pentaerythritol ester, and polytetrafluoroethylene modified polyethylene wax, preferably pentaerythritol ester; and / or The weathering agent is selected from at least one or more of high molecular weight hindered amine light stabilizers and UV absorbers, preferably at least one or more of UV absorber UV944 and light stabilizer 770.

4. The spray-free application method according to any one of claims 1-3, characterized in that, The toughening agent is selected from at least one or more of acrylates, silicones, and methacrylic ester-olefin copolymers, preferably at least one or more of methacrylic ester-butadiene-styrene and core-shell impact modifier M-732; and / or The color powder is selected from at least one or more of organic dyes, organic pigments, and inorganic pigments, preferably at least one or more of transparent blue 3R, titanium dioxide CR211, and carbon black 9A32.

5. A method for preparing spray-free coating points for polycarbonate materials according to any one of claims 1-4, characterized in that, Includes the following steps: 1) Preparation of the dotting base material: Polytetrafluoroethylene resin, antioxidant, lubricant, weathering agent, toughening agent and color powder are mixed. The mixture is extruded and granulated by an extruder to obtain the dotting base material. 2) Preparation of the powder: Put the powder base material into a liquid nitrogen pulverizer, pulverize and sieve to obtain a powder with a mesh size of 20-100.

6. The preparation method according to claim 5, characterized in that, The liquid nitrogen pulverizer described in step 2) has a pulverization temperature of -100 to -196℃, a pulverizer speed of 5000 to 16000 r / min, and a liquid nitrogen pressure of 0.2 to 2 MPa.

7. A spray-free polycarbonate material with a dotting effect, characterized in that, The material comprises the spray-free coating point for polycarbonate materials as described in any one of claims 1-4, or the spray-free coating point for polycarbonate materials prepared by the method described in claim 5 or 6.

8. The dot-spraying effect spray-free polycarbonate material according to claim 7, characterized in that, The raw material composition includes the following weight percentages: Polycarbonate resin: 80-98%, preferably 85-97%. Antioxidant: 0.1-0.6%, Lubricant: 0.1-4%, Weather resistant agent: 0.3-6%, For spray-free application of polycarbonate materials: 0.5-10%, preferably 0.5-6%.

9. The dot-spraying effect spray-free polycarbonate material according to claim 8, characterized in that, The polycarbonate resin is at least one of the following: at 300°C and 1.2 kg, the melt index is 10 to 30 g / 10 min, preferably at least one of Wanhua Chemical 2350, 2220, 2100, and A1225.

10. The dot-spraying effect spray-free polycarbonate material according to claim 8 or 9, characterized in that, The antioxidant is at least one or more of phosphites, hindered amines, and high-efficiency compound antioxidants, preferably at least one or more of hindered amine 1076 and compound antioxidant B900; and / or The lubricant is at least one or more of zinc stearate, ethylene bis-stearamide, pentaerythritol ester, and polytetrafluoroethylene modified polyethylene wax, preferably pentaerythritol ester; and / or The weathering agent is one or more of a high molecular weight hindered amine light stabilizer and an ultraviolet absorber.

Images