A composition capable of being laser-engraved with white markings of high surface hardness, and a method of preparing and using the same

Abstract

The present application relates to a kind of compositions that can be engraved with high surface hardness white mark and its preparation method and application.The compositions that can be engraved with high surface hardness white mark include polymethyl methacrylate, styrene-acrylonitrile copolymer, acrylate rubber and black and white laser marking agent.The compositions that can be engraved with high surface hardness white mark provided by the present application are black and white after laser, and the white mark obtained has the same surface hardness as the composition before engraving, showing excellent scratch resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of plastic laser engraving, and particularly relates to a composition capable of laser engraving white marks with high surface hardness, a preparation method thereof and application. BACKGROUND

[0002] The plastic laser marking black-to-white process can present white marks on the black plastic surface, thereby achieving the effects of decorating the appearance and modifying the surface. Unlike the principle of laser marking white-to-black surface carbonization, laser marking black-to-white is to convert light energy into heat energy on the plastic surface, melt the plastic surface, generate bubbles, and reflect or scatter light on the tiny bubbles, so that the white marks are clearly visible. Since a bubble layer needs to be formed on the surface, the surface hardness of the white marks after laser engraving is very low compared to the surface hardness of the product before laser engraving, and the white marks are easily scratched by nails to form scratches, which seriously affects the appearance.

[0003] At present, a large-angle curved transparent scratch-free AS alloy laser engraving material has been disclosed in a patent, which uses a specific ratio of acrylonitrile-styrene copolymer resin and polymethyl methacrylate resin as a base material, and adds a compatible toughening agent to simultaneously combine the advantages of acrylonitrile-styrene copolymer resin and polymethyl methacrylate resin, and improve the transparency and toughness. The obtained AS alloy laser engraving material has good transparency, laser engraving performance and mechanical properties, but it does not specifically improve the hardness of the laser engraved area.

[0004] Therefore, it is of great research significance and application value to develop a laser engraving material capable of laser engraving white marks with high surface hardness. SUMMARY

[0005] The present application aims to overcome the defects or deficiencies of the low surface hardness of white marks after laser engraving of the prior art laser engraving material, and provides a composition capable of laser engraving white marks with high surface hardness. The composition capable of laser engraving white marks with high surface hardness provided by the present application has the same surface hardness as the composition before laser engraving after laser marking black-to-white, and exhibits excellent scratch resistance.

[0006] Another object of the present application is to provide a preparation method of the above-mentioned composition capable of laser engraving white marks with high surface hardness.

[0007] Another object of the present application is to provide the application of the above-mentioned composition capable of laser engraving white marks with high surface hardness in preparing products with white marks.

[0008] To achieve the above-mentioned objects, the present application adopts the following technical solutions:

[0009] A composition capable of laser engraving white marks with high surface hardness comprises the following components in parts by weight:

[0010] polymethyl methacrylate 100 parts,

[0011] styrene-acrylonitrile copolymer 20~40 parts,

[0012] acrylate rubber 15~50 parts,

[0013] black and white laser marking agent 0.01~0.05 parts.

[0014] The bubble layer formed on the surface when the white mark is obtained by laser engraving in the black and white process is the key reason for making the hardness of the white mark significantly lower than the hardness of the non-laser engraved area. For example, if only bubbles are generated inside the substrate during laser engraving, and the surface of the substrate does not foam, this problem can undoubtedly be avoided.

[0015] The inventors of the present application have found through repeated research that, by compounding polymethyl methacrylate, styrene-acrylonitrile copolymer and acrylate rubber as the base resin, and under the action of the black and white laser marking agent, only bubbles are generated inside the substrate during laser engraving, and the surface of the substrate does not foam, the white mark obtained has the same surface hardness as the composition before laser engraving, and exhibits excellent scratch resistance.

[0016] The amount and ratio of the three compounds of polymethyl methacrylate, styrene-acrylonitrile copolymer and acrylate rubber, and the amount of the black and white laser marking agent have a very large influence on the location of bubble generation. By adjusting the amount of the three compounds of polymethyl methacrylate, styrene-acrylonitrile copolymer and acrylate rubber within a suitable range, the light transmittance of the substrate can be adjusted, and the amount of the black and white laser marking agent is also adjusted, thereby adjusting the location of bubble generation. Research shows that the specific ratio of the substrate and the remaining components of the present application gives the composition a light transmittance of not less than 60%, and can form a white mark with a relatively high surface hardness. As the light transmittance increases, the surface hardness of the white mark changes little. If the light transmittance of the substrate is too low, the laser will mark on the surface of the composition during laser engraving, forming a foam layer on the surface, which will cause the hardness of the white mark to decrease and be easily scratched. If the amount of the black and white laser marking agent is too small, it cannot be well laser engraved. If the amount of the black and white laser marking agent is too large, during laser engraving, the laser will form a large number of bubbles inside and on the surface of the composition, which will also cause the surface hardness of the white mark obtained by laser engraving to decrease and be easily scratched.

[0017] Preferably, the laser-engravable white mark with high surface hardness composition comprises the following components in the following weight proportions:

[0018] polymethyl methacrylate 100 parts,

[0019] styrene-acrylonitrile copolymer 25~35 parts,

[0020] acrylate rubber 25~35 parts,

[0021] The black-to-white laser marking agent is 0.02-0.04 parts.

[0022] Preferably, the laser-engravable high-surface-hardness white marking composition has a light transmittance of ≥60%, further preferably 60-70%, at a thickness of 2.0 mm according to the standard GBT 2410-2008.

[0023] Preferably, the polymethyl methacrylate has a melt index of 7-10 ml / 10 min at 230°C and 3.8 kg according to ISO 1133-2011.

[0024] Preferably, the styrene-acrylonitrile copolymer has a refractive index of 1.55-1.57.

[0025] The refractive index is determined according to the inspection standard GB / T 39691-2020.

[0026] Preferably, the acrylate rubber is acrylonitrile-styrene-acrylate copolymer.

[0027] Preferably, the acrylate rubber has a D50 particle size of 100-500 nm.

[0028] The D50 particle size of the acrylate rubber is determined according to the standard GB / T 19077-2016 using a laser particle size analyzer. Preferably, the black-to-white laser marking agent is carbon black.

[0029] The preparation method of the laser-engravable high-surface-hardness white marking composition comprises the following steps: uniformly mixing polymethyl methacrylate, styrene-acrylonitrile copolymer, acrylate rubber, and black-to-white laser marking agent to obtain a mixture, and then melt-extruding and granulating the mixture to obtain the laser-engravable high-surface-hardness white marking composition.

[0030] Preferably, the preparation method of the laser-engravable high-surface-hardness white marking composition comprises the following steps: uniformly mixing polymethyl methacrylate, styrene-acrylonitrile copolymer, acrylate rubber, and black-to-white laser marking agent in a high-speed mixer to obtain a mixture, and then melt-extruding and granulating the mixture in a twin-screw extruder to obtain the laser-engravable high-surface-hardness white marking composition.

[0031] More preferably, the mixing is performed using a high-speed mixer at a stirring speed of 60-100 rpm for 3-5 min.

[0032] Preferably, melt extrusion is carried out using a twin-screw extruder, and the extrusion temperature of the twin-screw extruder is 160-220 DEG C, the length-diameter ratio is 40-65:1, and the screw rotation speed is 300-450 rpm.

[0033] The composition capable of engraving a white mark with high surface hardness is also used in the preparation of an article engraved with a white mark, such as a black household appliance.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] The composition capable of engraving a white mark with high surface hardness is also used in the preparation of an article engraved with a white mark, such as a black household appliance. DETAILED DESCRIPTION

[0036] The present application is further described below in conjunction with examples. These examples are only used to illustrate the present application and are not used to limit the scope of the present application. The experimental methods in the following examples are not specified, and are generally carried out according to conventional conditions or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used are commercially available raw materials and reagents unless otherwise specified. Any non-essential changes and substitutions made by those skilled in the art based on the present application are within the scope of the present application.

[0037] Some reagents used in the examples and comparative examples of the present application are described as follows:

[0038] Poly (methyl methacrylate) 1#: Jimei, PMMA CM-207, the melt index under the conditions of 230 DEG C and 3.8 kg is 8.5 ml / 10 min according to ISO1133-2011.

[0039] Poly (methyl methacrylate) 2#: Jimei, PMMA CM-211, the melt index under the conditions of 230 DEG C and 3.8 kg is 16 ml / 10 min according to ISO1133-2011.

[0040] Styrene-acrylonitrile copolymer 1#: South Korea Kumho, SAN 310NTR, refractive index 1.56.

[0041] Styrene-acrylonitrile copolymer 2#: South Korea Kumho, SAN 350N, refractive index 1.57.

[0042] Acrylate rubber 1#: acrylonitrile-styrene-acrylate copolymer, Zhejiang Suiqi New Material, Q500, D50 particle size 100 nm.

[0043] Acrylate rubber 2#: acrylonitrile-styrene-acrylate copolymer, Zhejiang Suiqi New Material, Q350, D50 particle size 500 nm.

[0044] Black and white laser marking agent 1#: carbon black, DENKA BLACK, Nippon Electric Chemicals Co., Ltd.

[0045] Black and white laser marking agent 2#: carbon black, Anhui Heiyu Pigment New Material Co., Ltd., 1013F.

[0046] The composition (or the composition capable of engraving a white mark with high surface hardness) in the examples and comparative examples of the present application is prepared by the following process:

[0047] The raw materials are weighed and placed in a mixer with a rotation speed of about 100 rpm for dry mixing for 4 minutes. Then the mixed raw materials are melt-extruded and pelletized in a twin-screw extruder with a length-diameter ratio of 40:1 and a temperature range of 160℃, 190℃, 190℃, 200℃, 210℃, 210℃, 210℃, 220℃, 220℃, 220℃, 220℃, and a rotation speed of 450 rpm / min to obtain plastic particles, which are the composition (or the composition capable of engraving a white mark with high surface hardness).

[0048] The plastic particles are injection molded into a color plate (thickness 2 mm) at about 200℃. Then, using a Rayjet EP-12 laser marking machine, a white mark is engraved under the conditions of a current of 20 A, a marking speed of 1000 mm / s, and a frequency of 17 KHz.

[0049] The color, pencil hardness, light transmittance, and surface scratch resistance of the color plate before engraving are tested, and the color, pencil hardness of the white mark surface, and surface scratch resistance of the white mark after engraving are tested. The test position points before and after engraving are consistent.

[0050] (1) Color: observed by naked eye under visible light; at the same time, L value was measured by color difference meter according to GB / T 11186-1989 standard.

[0051] (2) Pencil hardness: measured according to GB / T 6739-2006 standard.

[0052] (3) Light transmittance: measured according to GB / T 2410-2008 standard, thickness 2 mm.

[0053] (4) Surface scratch resistance: observed by naked eye under visible light after pencil hardness test, no scratch represents scratch resistance, scratch represents no scratch resistance.

[0054] Examples 1-11

[0055] The present examples provide a series of compositions capable of engraving high surface hardness white marks, the amounts of components in the formulations of which are shown in Table 1.

[0056] Table 1 Formulations (parts) of Examples 1-11

[0057]

[0058] Comparative Examples 1-7

[0059] The present comparative examples provide a series of compositions, the amounts of components in the formulations of which are shown in Table 2.

[0060] Table 2 Formulations (parts) of Comparative Examples 1-7

[0061]

[0062] The properties of the compositions (or compositions capable of engraving high surface hardness white marks) provided by the examples and comparative examples were tested according to the aforementioned performance test methods, and the results are shown in Table 3.

[0063] Table 3 Performance test results of the compositions provided by Examples 1-11 and Comparative Examples 1-7

[0064]

[0065] As can be seen from the above test results, Comparative Example 7 directly uses polymethyl methacrylate as the engraving substrate, and the engraving is prone to coking and blackening, and white marks cannot be formed. The compositions capable of engraving high surface hardness white marks provided by Examples 1-9 are compounded by three types of resins, and the light transmittance of the obtained compositions is more than 60%. Not only can white marks be engraved, but also the pencil hardness of the engraved marks can reach H or 2H, and the compositions have excellent surface scratch resistance, which is consistent with the pencil hardness of the substrate before engraving, and have good application prospects in the field of black household appliances. In Comparative Examples 1 and 2, the addition amount of styrene-acrylonitrile copolymer is too low or too high, which results in a light transmittance of less than 60%. Although white marks can be formed by laser marking, the surface is severely foamed, the pencil hardness is less than 6B, and the scratch resistance is poor. In Comparative Example 3, the addition amount of black-to-white laser marking agent is too low, although the light transmittance before engraving is more than 60%, but it cannot be engraved. In Comparative Example 4, the addition amount of black-to-white laser marking agent is too high, the substrate engraving is out of control, resulting in a large number of bubbles in the substrate and on the surface. Although white marks can be formed by laser marking, the surface is severely foamed, the pencil hardness is less than 6B, and the scratch resistance is poor. In Comparative Examples 5 and 6, the addition amount of acrylate rubber is too low or too high, which results in a light transmittance of less than 60%. Although white marks can be formed by laser marking, the surface is severely foamed, the pencil hardness is less than 6B, and the scratch resistance is poor.

[0066] Those skilled in the art will appreciate that the embodiments described herein are presented for purposes of illustration and that the inventive principles are not limited to these particular embodiments. Other variations and modifications can be made to the embodiments without departing from the spirit and scope of the inventive principles.

Claims

1. A composition capable of laser-engraving high-surface-hardness white markings, characterized in that, The components include the following parts by weight: 100 parts of polymethyl methacrylate 20-40 parts of styrene-acrylonitrile copolymer 15-50 parts of acrylonitrile-styrene-acrylate copolymer Black-to-white laser marking agent: 0.01–0.05 parts; The composition capable of laser-engraving high surface hardness white marks, according to GBT 2410-2008 standard, has a light transmittance of 60-70% at a thickness of 2.0 mm; The black-to-white laser marking agent is carbon black; The acrylonitrile-styrene-acrylate copolymer is either Zhejiang Suqi New Material's Q500 or Zhejiang Suqi New Material's Q350.

2. The composition according to claim 1, capable of laser-engraving high surface hardness white markings, characterized in that, The components include the following parts by weight: 100 parts of polymethyl methacrylate 25-35 parts of styrene-acrylonitrile copolymer, 25-35 parts of acrylonitrile-styrene-acrylate copolymer Use 0.02 to 0.04 parts of black-to-white laser marking agent.

3. The composition according to claim 1, capable of laser-engraving high surface hardness white markings, is characterized in that, The polymethyl methacrylate, according to ISO 1133-2011, has a melt index of 7-10 ml / 10 min at 230°C and 3.8 kg.

4. The composition according to claim 1, capable of laser-engraving high surface hardness white markings, characterized in that, The refractive index of styrene-acrylonitrile copolymer is 1.55 to 1.

57.

5. The composition capable of laser-engraving high surface hardness white markings according to any one of claims 1, characterized in that, The D50 particle size of the acrylonitrile-styrene-acrylate copolymer is 100-500 nm.

6. A method for preparing the composition capable of laser-engraving high surface hardness white marks according to any one of claims 1 to 5, characterized in that, The process includes the following steps: mixing polymethyl methacrylate, styrene-acrylonitrile copolymer, acrylonitrile-styrene-acrylate copolymer and black-to-white laser marking agent evenly to obtain a mixture, then melting and extruding the mixture, and granulating it to obtain the composition that can laser-engrave white marks with high surface hardness.

7. The use of the composition according to any one of claims 1 to 5 capable of laser engraving white marks with high surface hardness in the preparation of articles with laser engraved white marks.

Images