1. A preparation method of baking varnish-imitated black highlight spraying-free aesthetic plastic is characterized by comprising the following specific steps:

(1) adding natural crystalline flake graphite, pigment black 28, a dispersing agent and ABS powder into a stirrer, stirring and grinding for 30-60min, and then adding flash mica, grinding for 1-3min to obtain a pretreated pigment;

(2) adding granular ABS, spherical barium sulfate, a lubricant, a light stabilizer and an antioxidant into a high-speed mixer for dispersion to obtain premixed ABS;

(3) adopting a double-stage screw extruder as granulation equipment, wherein the first stage is a co-rotating parallel double-screw extruder, and the second stage is a reciprocating screw extruder; adding the premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding the pretreatment pigment into a second-stage reciprocating screw extruder, and performing dispersion mixing, extrusion granulation on the pretreatment pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic.

2. The method for preparing the baking varnish-imitated black high-gloss spray-free aesthetic plastic according to claim 1, wherein the baking varnish-imitated black high-gloss spray-free aesthetic plastic comprises the following steps:

the pigment black 28 is copper chromium black with the particle size of less than 2 mu m;

the dispersing agent is sodium dodecyl benzene sulfonate;

the particle size of the ABS powder is less than 20 μm;

the spherical barium sulfate is particles with the particle size of less than 5 mu m;

the lubricant is at least one of paraffin and silicone powder;

the light stabilizer is at least one of UV-329 and TH-944;

the antioxidant is at least one of antioxidant 1010 and antioxidant 168.

3. The method for preparing the baking varnish-imitated black high-gloss spray-free aesthetic plastic according to claim 1, wherein the baking varnish-imitated black high-gloss spray-free aesthetic plastic comprises the following steps: the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent and the ABS powder in the step (1) is 15-20: 5-10: 3-5: 0.5-1: 50-60.

4. The method for preparing the imitation baking varnish black highlight spraying-free aesthetic plastic as claimed in claim 1, wherein in the step (1), zirconia is added into the stirrer as an auxiliary grinding medium; the particle size of the zirconia is 0.3 mm; the addition amount of the zirconium oxide is 0.5-1 time of the total mass of the pretreated pigment.

5. The method for preparing the imitation baking varnish black highlight free-spraying aesthetic plastic as claimed in claim 1, wherein the stirring speed of the stirrer in the step (1) is controlled to be 80-100 rpm.

6. The preparation method of the baking varnish-imitated black highlight spray-free aesthetic plastic as claimed in claim 1, wherein the mass ratio of the granular ABS, the spherical barium sulfate, the lubricant, the light stabilizer and the antioxidant in the step (2) is 100: 3-8: 0.5-1: 0.05-0.1: 0.05-0.1.

7. The method for preparing the baking varnish-imitated black highlight spray-free aesthetic plastic as claimed in claim 1, wherein the mass ratio of the pretreatment pigment to the premixed ABS in the step (3) is 20-30: 100.

8. the method for preparing the baking varnish-imitated black highlight spray-free aesthetic plastic as claimed in claim 1, wherein the screw temperature of the co-rotating parallel twin-screw extruder in the step (3) is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

9. A simulated stoving varnish black high gloss spray-free aesthetic plastic prepared by the preparation method of any one of claims 1 to 8.

Background

The plastic material has the advantages of low density, low price and convenient manufacture, and is widely applied in the fields of automobile manufacture, electric appliance shells, daily necessities, aerospace, artware and the like. However, because the plastic products have the defects of uneven color, monotonous color, high rejection rate, high recycling difficulty and the like during mould pressing, the plastic products are coated by paint and processed according to the requirements of color, luster, patterns and the like, so that the defects of uneven color, monotonous color, mottling, scratches and the like can be covered, and the antifouling, antistatic performance, hand feeling and aesthetic property of the products can be greatly improved.

In order to further improve the quality of plastic products and overcome the problems of environmental pollution, scratch resistance and the like caused by coating on the surface of a plastic product piece, the technology of spraying aesthetic plastics without coating is rapidly developed in recent years. The spraying-free aesthetic plastic is a functional plastic which can be directly formed into a high-quality appearance through one-step injection molding through special modification treatment on the plastic, and can be designed to obtain different textures of metal, pearlescence, a flashing effect and the like according to requirements. The core of the method is that the functional pigment is efficiently dispersed in the resin, surface spraying and modification are not needed, and the method is environment-friendly and pollution-free. The plastic can greatly improve the quality of plastic products, and particularly meet the requirements of differentiated, personalized, diversified and differentiated customers.

In particular practice, the high gloss improvement of spray-free plastics has been a problem. The reason for this is that the pigment is dispersed in the resin and largely affects the glossiness due to the influence of dispersibility. The conventional baking varnish adopts high-flow coating, is dispersed and sprayed under high pressure, and has fully dispersed pigment, bright color, strong visual impact, good surface smoothness and excellent luster. The current black baking varnish greatly improves the product quality in high-grade furniture, automobiles and toys. And the gloss of the spray-free resin is difficult to achieve to such a high degree.

The Chinese patent application No. 201710931933.6 discloses a spray-free plastic shell formula, which is prepared from the following elements in percentage by weight, including 1.3-2.5% of metal powder, 0.02% of carbon black, 0.1% of antioxidant, 0.2% of dispersant and 0.5% of high gloss toner, and the balance being plastic raw material PP or ABS, wherein the total percentage by weight of the components is 100%. The Chinese patent application No. 201910849853.5 discloses a spray-free composite polypropylene plastic for replacing ABS and a preparation method thereof, wherein the composite polypropylene plastic is prepared by banburying a material prepared by reacting dimethyl terephthalate, ethylene glycol, polyethylene glycol, zinc acetate, pentaerythritol, a branching degree regulator, phosphite ester, mullite whisker, nano talc powder and mica powder serving as raw materials with fluorinated polyurethane elastomer, methacrylate-butadiene-styrene copolymer and calcium acetylacetonate to obtain enhanced highlight body, and then mixing the enhanced highlight body with polypropylene, an antioxidant, a lubricant and hollow glass microspheres, extruding and granulating. Although the technology improves the surface gloss effect of the spraying-free plastic to a certain extent, the effect is still not ideal, and the gloss and brightness level of the baking varnish cannot be achieved.

How to improve the gloss of the black spraying-free resin to the degree of baking finish will produce great effect on improving the product quality. In the prior art, carbon black is mainly prepared into black master batch, and then the black master batch is dispersed in resin to prepare the spray-free black resin material. Since carbon black is poorly dispersed in a resin having a high viscosity, it is difficult to achieve high gloss and high brightness.

Disclosure of Invention

In order to enable the spraying-free aesthetic plastic to achieve a black highlight effect similar to the gloss of baking finish, the invention provides baking finish-imitating black highlight spraying-free aesthetic plastic and a preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of baking varnish-imitated black highlight spraying-free aesthetic plastic is characterized by comprising the following specific steps:

(1) adding natural crystalline flake graphite, pigment black 28, a dispersing agent and ABS powder into a stirrer, stirring and grinding for 30-60min, and then adding flash mica, grinding for 1-3min to obtain a pretreated pigment;

(2) adding granular ABS, spherical barium sulfate, a lubricant, a light stabilizer and an antioxidant into a high-speed mixer for dispersion to obtain premixed ABS;

(3) adopting a double-stage screw extruder as granulation equipment, wherein the first stage is a co-rotating parallel double-screw extruder, and the second stage is a reciprocating screw extruder; adding the premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding the pretreatment pigment into a second-stage reciprocating screw extruder, and performing dispersion mixing, extrusion granulation on the pretreatment pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic.

Preferably, the pigment black 28 is copper chromium black with a particle size of less than 2 μm.

Preferably, the dispersant is sodium dodecyl benzene sulfonate.

Preferably, the particle size of the ABS powder is less than 20 μm.

Preferably, the spherical barium sulfate is fine particles having a particle size of less than 5 μm.

Preferably, the lubricant is at least one of paraffin and silicone powder.

Preferably, the light stabilizer is at least one of UV-329 and TH-944.

Preferably, the antioxidant is at least one of antioxidant 1010 and antioxidant 168.

Preferably, the first stage of the double-stage screw extruder is a co-rotating parallel double screw extruder, and the second stage is a reciprocating screw extruder.

Preferably, the mass ratio of the natural crystalline flake graphite, the paragonite, the pigment black 28, the dispersing agent and the ABS powder in the step (1) is 15-20: 5-10: 3-5: 0.5-1: 50-60.

Preferably, zirconia is added to the blender in step (1) as an auxiliary grinding medium.

More preferably, the particle size of the zirconia is 0.3 mm.

Further preferably, the addition amount of the zirconia is 0.5 to 1 time of the total mass of the pretreated pigment.

Preferably, the stirring speed of the stirrer in the step (1) is controlled to be 80-100 rpm.

Preferably, the mass ratio of the granular ABS, the spherical barium sulfate, the lubricant, the light stabilizer and the antioxidant in the step (2) is 100: 3-8: 0.5-1: 0.05-0.1: 0.05-0.1.

Preferably, the mass ratio of the pretreated pigment to the premixed ABS in the step (3) is 20-30: 100.

preferably, the screw temperature of the co-rotating parallel twin-screw extruder in the step (3) is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section in sequence.

Preferably, the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section.

It is known that pigments flow more easily in paints and that the addition of dispersants enables good dispersion to be achieved, so that the gloss of the pigments is fully developed; on the other hand, when the pigment is dispersed in the resin in a molten state, the viscosity of the resin is high, which makes it difficult to disperse the pigment, and thus affects the gloss of the pigment. In order to promote the pigment to exert a gloss effect in plastics, it is a conventional practice to add a lubricating dispersant to promote the dispersion of the pigment and to enhance the dispersion effect by strong shear. However, excessive use of the lubricating dispersant causes a decrease in the strength of the resin and a decrease in the rigidity of the product, and excessive shearing causes a destruction of the flake structure of the pigment, resulting in a decrease in gloss.

The method adopts a two-step method to prepare the pretreated pigment, wherein in the first step, zirconium oxide is used as an auxiliary grinding medium, natural crystalline flake graphite, pigment black 28, a dispersing agent and ABS powder are added into a stirrer for stirring and grinding, so that the natural crystalline flake graphite is stripped into multi-layer graphene micro-sheets and is in good contact with the pigment black 28 and the ABS powder, the ABS powder is a grinding medium and a composite matrix, and the graphene micro-sheets, the pigment black 28 and the ABS powder form good dispersion through grinding, and are more easily dispersed in an ABS melt subsequently; and the second step is that the flashing mica is added into the system in the first step to be continuously ground, the flashing mica is added after the graphene micro-sheets are stripped, the phenomenon that the sheet structure of the flashing mica is excessively damaged to influence the gloss effect can be avoided, and the pigment has good gloss and the flashing effect by matching the flashing mica with the graphene micro-sheets and the pigment black 28.

Furthermore, the pigment black 28 is copper-chromium black with the particle size of less than 2 μm, and has the advantages of environmental protection, no toxicity, high temperature resistance, no migration, easy dispersion and the like; the particle size of the used ABS powder is less than 20 μm, which is beneficial to grinding natural crystalline flake graphite as a medium and pre-dispersing the natural crystalline flake graphite with the natural crystalline flake graphite; in addition, the known spherical barium sulfate has good fluidity, and the use of the spherical barium sulfate in the premixed ABS ensures that the processing fluidity of the ABS is better, thereby being beneficial to the dispersion of the pigment at the later stage.

Furthermore, the invention adopts a double-stage screw extruder as an extruding device to carry out extrusion granulation, wherein the first stage is a co-rotating parallel double-screw extruder, and the second stage is a reciprocating screw extruder; and adding the premixed ABS in the first step for melt extrusion, adding the pretreated pigment and the premixed ABS in the second step for dispersion mixing, extruding and granulating. The shear force of the co-rotating parallel double-screw extruder is strong, the spherical barium sulfate is favorably dispersed in the ABS melt, the shear force of the reciprocating screw extruder is small, and good dispersion can be realized through reciprocation, so that the pretreated pigment is dispersed in the ABS melt, the small shear force can avoid the phenomenon that the laminar structure of the flash mica is damaged due to excessive shearing, and the gloss effect of the pretreated pigment is maintained while good dispersion is realized.

Under the improved process, the pretreated pigment can form good dispersion, and the pretreated pigment can be easily dispersed in ABS melt, and no more lubricating dispersant needs to be added, so that the strength and rigidity of the product can be prevented from being reduced.

The invention also provides the baking varnish-imitated black high-gloss spraying-free aesthetic plastic prepared by the method.

The prior spraying-free aesthetic plastic is difficult to achieve the black highlight effect similar to the gloss of baking varnish, and the application of the prior spraying-free aesthetic plastic is limited. In view of the above, the invention provides baking varnish-imitated black high-gloss spraying-free aesthetic plastic and a preparation method thereof, wherein natural crystalline flake graphite, pigment black 28, a dispersing agent and ABS powder are added into a stirrer to be stirred and ground for 30-60min, and then flash mica is added to be ground for 1-3min to obtain a pretreated pigment; on the other hand, the pigment is uniformly dispersed in advance by grinding and compounding with ABS powder, so that the defect of nonuniform dispersion in the extrusion of a screw machine is avoided; adding granular ABS, spherical barium sulfate, a lubricant, a light stabilizer and an antioxidant into a high-speed mixer for dispersion to obtain premixed ABS; particularly, a double-stage screw extruder is adopted, and spherical barium sulfate and silicone powder are dispersed in the ABS melt by the aid of the shearing force of the co-rotating parallel double-screw extruder in the first stage, so that the fluidity of the melt and the leveling property of a plastic product during processing are improved; and a reciprocating screw extruder is adopted in the second step, the shearing force is small, but the pigment can be well dispersed through reciprocating, so that the pretreated pigment is dispersed in the ABS melt, the high-shearing excessive shearing of the pretreated pigment is avoided, and the obtained plastic pigment is uniformly dispersed and has high glossiness. The prepared ABS material not only can keep higher strength and rigidity, but also can achieve the black highlight effect similar to the gloss of baking varnish.

The invention provides baking varnish-imitated black highlight spraying-free aesthetic plastic and a preparation method thereof, and compared with the prior art, the baking varnish-imitated black highlight spraying-free aesthetic plastic has the outstanding characteristics and excellent effects that:

1. the method adopts a two-step method to prepare the pretreated pigment, which is beneficial to the formation of good dispersion of the graphene micro-sheet, the pigment black 28 and the ABS powder, and the subsequent dispersion in the ABS melt is easier, and can avoid the influence on the gloss effect caused by the excessive damage of the sheet structure of the flash mica.

2. The invention improves the processing fluidity of ABS by using the spherical barium sulfate, and is beneficial to the dispersion of pigment in the later period.

3. The invention adopts a double-stage screw extruder as an extruding device to carry out extrusion granulation, promotes the dispersion of spherical barium sulfate in an ABS melt by utilizing the strong shearing force of a co-rotating parallel double-screw extruder, and utilizes a reciprocating screw extruder to realize the uniform dispersion of the pretreated pigment and the premixed ABS and prevent the damage of a laminar structure of flash mica caused by excessive shearing.

4. The invention can realize easy dispersion of the pretreated pigment in the ABS melt without adding more lubricating dispersant, and the prepared plastic can keep higher strength and rigidity and can achieve the black highlight effect similar to the gloss of baking varnish.

Drawings

FIG. 1: an imitation baking varnish black highlight free-spray aesthetic plastic sample was obtained from example 1.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.

Example 1

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, stirring and grinding at 100rpm for 30min, and then adding paragonite and grinding for 1min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent, the ABS powder and the zirconia is 20: 5: 5: 0.5: 50: 70;

(2) according to the mass ratio of 100: 3: 1: 0.05: 0.1 adding granular ABS, spherical barium sulfate with the particle size less than 5 mu m, paraffin, TH-944 and antioxidant 1010 into a high-speed mixer for dispersing to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 20: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Example 2

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, stirring and grinding at 80rpm for 60min, and then adding paragonite and grinding for 3min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent, the ABS powder and the zirconia is 15: 10: 3: 1: 60: 70;

(2) according to the mass ratio of 100: 8: 0.5: 0.1: 0.05 adding granular ABS, spherical barium sulfate with the particle size less than 5 mu m, silicone powder, UV-329 and antioxidant 168 into a high-speed mixer for dispersion to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 30: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Example 3

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, stirring and grinding at 90rpm for 40min, and then adding mica flash to grind for 2min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent, the ABS powder and the zirconia is 18: 8: 4: 0.8: 55: 60, adding a solvent to the mixture;

(2) according to the mass ratio of 100: 5: 0.8: 0.08: 0.08 adding granular ABS, spherical barium sulfate with the particle size of less than 5 mu m, paraffin, UV-329 and antioxidant 1010 into a high-speed mixer for dispersion to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 25: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Example 4

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, stirring and grinding at 85rpm for 40min, and then adding paragonite and grinding for 2min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent, the ABS powder and the zirconia is 16: 8: 4: 0.6: 57: 70;

(2) according to the mass ratio of 100: 6: 0.5: 0.09: 0.09 adding granular ABS, spherical barium sulfate with the particle size of less than 5 mu m, silicone powder, TH-944 and antioxidant 168 into a high-speed mixer for dispersion to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 22: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Example 5

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, stirring and grinding at 90rpm for 60min, and then adding paragonite and grinding for 1min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent, the ABS powder and the zirconia is 17: 7: 3.5: 0.7: 52: 60, adding a solvent to the mixture;

(2) according to the mass ratio of 100: 4: 0.5: 0.06: 0.07 adding granular ABS, spherical barium sulfate with the particle size less than 5 mu m, paraffin, UV-329 and antioxidant 168 into a high-speed mixer for dispersion to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 26: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Comparative example 1

(1) Adding graphene micro-sheets, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, and stirring and grinding at 100rpm for 1min to obtain a pretreated pigment; the mass ratio of the graphene nanoplatelets to the flash mica to the pigment black 28 to the dispersing agent to the ABS powder is 20: 5: 5: 0.5: 50;

(2) according to the mass ratio of 100: 3: 1: 0.05: 0.1 adding granular ABS, spherical barium sulfate with the particle size less than 5 mu m, paraffin, TH-944 and antioxidant 1010 into a high-speed mixer for dispersing to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 20: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Compared with the example 1, the natural crystalline flake graphite is not compounded with the ABS powder by grinding and peeling, but the graphene microchip is directly compounded with the ABS powder, and the rest is completely consistent with the example 1.

Comparative example 2

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, and stirring and grinding at 100rpm for 30min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite to the pigment black 28 to the dispersing agent to the ABS powder to the zirconia is 20: 5: 0.5: 50: 70;

(2) according to the mass ratio of 100: 3: 1: 0.05: 0.1 adding granular ABS, spherical barium sulfate with the particle size less than 5 mu m, paraffin, TH-944 and antioxidant 1010 into a high-speed mixer for dispersing to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 20: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Comparative example 1 compared to example 1, no flash mica was added, and the rest was identical to example 1.

Comparative example 3

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, stirring and grinding at 100rpm for 30min, and then adding paragonite and grinding for 1min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent, the ABS powder and the zirconia is 20: 5: 5: 0.5: 50: 70;

(2) according to the mass ratio of 100: 3: 1: 0.05: 0.1 adding granular ABS, spherical barium sulfate with the particle size less than 5 mu m, paraffin, TH-944 and antioxidant 1010 into a high-speed mixer for dispersing to obtain premixed ABS;

(3) according to the mass ratio of 20: 100, adding the pretreated pigment and the premixed ABS into a co-rotating parallel double-screw extruder, and performing dispersion mixing, extrusion granulation to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section in sequence.

Comparative example 1 compared with example 1, the twin-screw extruder was directly used for one-time mixing extrusion without using a twin-stage screw, and the other examples were completely identical with example 1.

Comparative example 4

(1) Adding natural crystalline flake graphite, pigment black 28 with the particle size of less than 2 microns, dispersant sodium dodecyl benzene sulfonate and ABS powder with the particle size of less than 20 microns into a stirrer, stirring and grinding at 100rpm for 30min, and then adding paragonite and grinding for 1min to obtain a pretreated pigment; adding zirconia with the particle size of 0.3mm into the stirrer as an auxiliary grinding medium; wherein the mass ratio of the natural crystalline flake graphite, the flash mica, the pigment black 28, the dispersing agent, the ABS powder and the zirconia is 20: 5: 5: 0.5: 50: 70;

(2) according to the mass ratio of 100: 0.05: 0.1 adding granular ABS, TH-944 and antioxidant 1010 into a high-speed mixer for dispersing to obtain premixed ABS;

(3) adding premixed ABS into a first-stage co-rotating parallel double-screw extruder, adding a pretreatment pigment into a second-stage reciprocating screw extruder, and mixing according to a mass ratio of 20: 100, dispersing, mixing, extruding and granulating the pretreated pigment and the premixed ABS to obtain the baking varnish-imitated black highlight spraying-free aesthetic plastic; the screw temperature of the co-rotating parallel double-screw extruder is 190 ℃, 210 ℃, 220 ℃, 230 ℃ and 235 ℃ from the feeding section to the discharging section; the screw temperature of the reciprocating screw extruder is 235 ℃, 230 ℃, 220 ℃ and 210 ℃ from the feeding section to the discharging section in sequence.

Comparative example 1 in comparison to example 1, no spherical barium sulfate and paraffin wax were added to the first stage feed, and the rest was identical to example 1.

The test method comprises the following steps:

and (3) testing the glossiness: the spraying-free aesthetic plastics obtained in the examples 1-5 and the comparative examples 1-4 are subjected to injection molding, and the injection molding process comprises the following steps: the charging barrel temperature is 235 ℃, the injection pressure is 15MPa, the nozzle temperature is 220 ℃, the mold temperature is 90 ℃, and the glossiness of the injection molding piece is tested; polishing the cross section of the injection molding piece, and testing the glossiness again; the test results are shown in table 1.

As can be seen from table 1: the pigment in the obtained aesthetic plastic is uniformly dispersed, the glossiness of the aesthetic plastic is close to that of baking finish, and the high-gloss effect is still kept after polishing, so that the material can be used for automobile shells, and can be polished as new after scraping; in comparative example 1, the composite dispersion of the pigment is slightly poor, and the influence on the glossiness is generated; comparative example 2 the gloss of the spray-free aesthetic plastic was slightly poor due to the absence of the addition of the sparkling mica; comparative example 3 the sheet structure of the flash mica was destroyed by one-time extrusion, which affects the gloss; in comparative example 4, the fluidity and the leveling property of ABS are slightly poor, which affects the dispersion of the pigment at the later stage and the glossiness.

Table 1:

performance index	Degree of gloss	Gloss of cross section polishing
			Example 1	81	79
Example 2	83	81
			Example 3	82	80
Example 4	81	78
			Example 5	83	80
Comparative example 1	75	72
			Comparative example 2	67	62
Comparative example 3	72	68
			Comparative example 4	70	66