A scratch-resistant matte oil for black substrates and its applications, including outer packaging materials.

Abstract

This invention discloses a scratch-resistant matte oil for black substrates and its application in packaging materials, relating to the field of coating technology. The scratch-resistant matte oil for black substrates comprises, by weight, the following components: 30-35 parts of water-based matte resin, 50-60 parts of solvent, 3-5 parts of matting powder, and 0.01-1 parts of a feel agent; wherein the water-based matte resin is a water-based polyurethane resin. The scratch-resistant matte oil provided by this invention uses a resin with a specific matte finish and controls the amount of resin and matting powder. After printing on a black substrate surface using the scratch-resistant matte oil, the reflectivity of the printed ink layer surface is below 3.5%, the blackness value (L) is below 25, and good scratch resistance is maintained. This invention can solve the problem that existing packaging products struggle to simultaneously achieve low blackness value (L<25), low matte finish, and good scratch resistance.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a scratch-resistant matte oil for black substrates and its applications, as well as outer packaging materials. Background Technology

[0002] In the packaging industry, screen printing is widely used for printing black inks due to its thick ink layer and strong opacity. In recent years, with the continuous upgrading of new products, the market demand for black packaging products that combine blackness (dark effect), low gloss (matte effect), and excellent scratch resistance has been increasing.

[0003] However, existing screen printing technology faces significant technical bottlenecks when simultaneously achieving the above-mentioned multiple performance indicators, making it difficult to meet the stringent requirements of high-end customers. Specifically, this manifests in the following aspects: (1) The contradiction between blackness value and optical performance: The black coating obtained through conventional screen printing processes usually has a blackness value (L value) of less than 25 on both sides, making it difficult to achieve a "dark" visual effect. To further reduce the L value and achieve a low-gloss matte effect, the traditional approach is to significantly increase the amount of carbon black powder and matting powder (such as silica). (2) Process and performance defects caused by formula adjustment: Although excessive addition of carbon black powder and matting powder can improve matteness and blackness to a certain extent, it will trigger a series of chain negative effects, such as increasing ink viscosity and concentration, reducing fluidity, and seriously affecting the processability during printing; moreover, the excessively thick ink layer and excessive powder hinder the penetration of ultraviolet light, which will lead to incomplete ink drying and poor curing, thereby affecting the final performance of the coating. (3) A single process cannot achieve multiple effects: Due to the limitations of the above-mentioned material formulations, the existing single-step screen printing process is difficult to simultaneously present a composite effect of high blackness, low gloss, specific haze and high scratch resistance on the same product surface. If it is attempted to achieve this through multiple printings or complex post-processing, it will not only be costly, but also have a low yield rate, making it difficult to scale up production.

[0004] Therefore, existing technologies still lack a solution that can balance low blackness (L<25), low matte finish, and good scratch resistance. Summary of the Invention

[0005] The main objective of this invention is to propose a scratch-resistant matte oil for black substrates and its application in outer packaging materials, aiming to solve the problem that existing outer packaging products cannot simultaneously achieve low blackness (L<25), low matteness, and good scratch resistance.

[0006] To achieve the above objectives, the present invention proposes a scratch-resistant matte oil for black substrates, comprising the following components by weight: 30-35 parts of water-based matte resin, 50-60 parts of solvent, 3-5 parts of matting powder, and 0.01-1 parts of hand feel agent; wherein the water-based matte resin is a water-based polyurethane resin.

[0007] In one embodiment, the coating formed after curing the waterborne polyurethane resin has a gloss level of <10 GU at a 60° angle.

[0008] In one embodiment, the solvent comprises deionized water; and / or,

[0009] The tactile agent includes polysiloxane; and / or, The matte powder comprises fumed silica; and / or, The substrate material of the black substrate includes at least one of polycarbonate, polyethylene, and polyethylene terephthalate.

[0010] In one embodiment, the scratch-resistant matte oil for black substrates further includes 0.02 to 1.5 parts of bactericide.

[0011] In one embodiment, the bactericide includes at least one of methylisothiazolinone and 1,2-benzisothiazolin-3-one.

[0012] In one embodiment, the scratch-resistant matte oil for black substrates further includes 0.1 to 0.3 parts of defoamer.

[0013] This invention also proposes the application of the scratch-resistant matte oil for black substrates as described in the foregoing technical solution in the preparation of outer packaging materials, comprising the following steps: A black substrate is provided, and the scratch-resistant matte varnish for the black substrate described in the aforementioned technical solution is printed on the black substrate. After drying, the outer packaging material is obtained.

[0014] In one embodiment, the black substrate has a reflectivity of less than 10% and a blackness value L of less than 28; and / or, The printing thickness of the scratch-resistant matte varnish used on the black substrate is 5~8μm.

[0015] The present invention also proposes an outer packaging material, wherein the outer packaging material comprises the scratch-resistant matte oil for black substrate as described in the foregoing technical solution, or the outer packaging material is obtained by the application described in the foregoing technical solution.

[0016] In one embodiment, the reflectivity of the outer packaging material is less than 3.5%, and the blackness value L is less than 25.

[0017] In the technical solution of this invention, the scratch-resistant matte varnish for black substrates uses a specific water-based matte resin, and the amounts of water-based matte resin and matte powder are controlled. After printing on the surface of a black substrate using the scratch-resistant matte varnish, the reflectivity of the substrate on the surface of the printed ink layer is less than 3.5%, and the blackness value (L value) is less than 25, achieving the effect of low blackness value and low matteness. At the same time, because the amount of matte powder is greatly reduced, the scratch-resistant matte varnish also improves the problem of poor scratch resistance caused by excessive matte powder. Therefore, the scratch-resistant matte varnish provided by this invention can take into account low blackness value, low matteness, and good scratch resistance, solving the problem that existing outer packaging products cannot take into account low blackness value (L<25), low matteness, and good scratch resistance. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0020] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0021] In recent years, with the continuous upgrading of new products, the market demand for black packaging products that combine blackness (dark effect), low gloss (matte effect), and excellent scratch resistance has been increasing. However, existing screen printing technology faces significant technical bottlenecks in achieving these multiple performance indicators simultaneously, making it difficult to meet the stringent requirements of high-end customers.

[0022] Currently, black coatings obtained primarily through conventional screen printing processes typically struggle to reduce the blackness value (L value) of both sides to below 25, thus failing to achieve a truly "dark" visual effect. To further reduce the L value and achieve a low-gloss matte finish, the traditional approach often involves significantly increasing the amount of carbon black powder and matting agents (such as silica). While excessive addition of carbon black powder and matting agents can improve matteness and blackness to some extent, it triggers a series of negative effects. For example, it increases ink viscosity and concentration, reduces fluidity, and severely impacts processability during printing. Furthermore, an excessively thick ink layer and too much powder hinder ultraviolet light penetration, leading to incomplete ink drying and poor curing, ultimately affecting the final coating performance. Therefore, existing technologies still lack a solution that can simultaneously achieve low blackness (L<25), low matteness, and good scratch resistance.

[0023] In view of this, the present invention proposes a scratch-resistant matte oil for black substrates, comprising the following components by weight: 30-35 parts of water-based matte resin, 50-60 parts of solvent, 3-5 parts of matting powder, and 0.01-1 parts of hand feel agent; wherein the water-based matte resin is a water-based polyurethane resin.

[0024] Conventional matte oils are basically composed of resin, solvent, matting powder, and additives. Among them, glossy resins are often used (glossy resins usually have better leveling properties and can reduce surface defects such as orange peel and pinholes; they are also cheaper). In order to achieve a low-matte effect, the proportion of matting powder is usually very high (around 20%). However, an excessively high proportion of matting powder will weaken the scratch resistance of the coating and cause powdering.

[0025] In the technical solution of this invention, the scratch-resistant matte varnish for black substrates uses a specific water-based matte resin, and the amounts of water-based matte resin and matte powder are controlled. After printing on the surface of a black substrate using the scratch-resistant matte varnish, the reflectivity of the substrate on the surface of the printed ink layer is less than 3.5%, and the blackness value (L value) is less than 25. At the same time, because the amount of matte powder is greatly reduced, the scratch-resistant matte varnish also improves the problem of poor scratch resistance caused by excessive matte powder. Therefore, the scratch-resistant matte varnish provided by this invention can balance low blackness value, low matteness, and good scratch resistance, solving the problem that existing outer packaging products cannot balance low blackness value (L<25), low matteness, and good scratch resistance.

[0026] It should be noted that, compared with other waterborne matte resin materials, the use of waterborne polyurethane resin as the resin takes advantage of the large number of urethane bonds (-NH-COO-) in the polyurethane molecular chain, which is conducive to the formation of a very strong hydrogen bond network, giving the coating extremely high toughness, elasticity and cohesion, and exhibiting excellent scratch resistance.

[0027] In embodiments of the present invention, the coating formed after curing the waterborne polyurethane resin has a gloss level of <10 GU at a 60° angle. If the resin has too high a matte finish (surface brightness) and a high gloss, the reflectivity will be correspondingly high, failing to achieve the desired matte tactile effect. As an example, in one embodiment of the present invention, a waterborne polyurethane resin with CAS number 68400-67-9 is used, which has moderate matte finish and hydrophilicity, while also exhibiting a good soft-feel effect.

[0028] In an embodiment of the present invention, the solvent includes deionized water.

[0029] In embodiments of the present invention, the tactile agent comprises polysiloxane. As a tactile agent, polysiloxane forms a lubricating film on the coating surface, resulting in a dry, smooth, and non-greasy feel, achieving an "anti-tactile" effect. Furthermore, polysiloxane can also act as a leveling agent, reducing the surface tension of the coating, improving leveling properties, and making the surface uniform and smooth.

[0030] In embodiments of the present invention, the matting powder comprises fumed silica. Fumed silica has a small particle size, high transparency, and a good feel. Using fumed silica as a matting powder can increase surface energy and produce a good matte effect. As an example, in one embodiment of the present invention, fumed silica with CAS number 7631-86-9 is used.

[0031] In embodiments of the present invention, the substrate material of the black substrate includes at least one of polycarbonate (PC), polyethylene (PE), and polyethylene terephthalate (PET). The scratch-resistant matte varnish for black substrates provided by the present invention can be used on black substrates of varying thicknesses. By printing the scratch-resistant matte varnish, the blackness value can be directly reduced, achieving a matte black finish and scratch resistance exceeding 1000 cycles (based on a 4-pound load and a 4-speed back-and-forth friction test).

[0032] In an embodiment of the present invention, the scratch-resistant matte oil for black substrates further includes 0.02 to 1.5 parts of bactericide.

[0033] In embodiments of the present invention, the bactericide includes at least one of methylisothiazolinone (MIT) and 1,2-benzisothiazolin-3-one (BIT). MIT is a highly effective, heat-resistant, water-based preservative that can effectively inhibit the growth of bacteria, fungi, and molds; 1,2-benzisothiazolin-3-one is a broad-spectrum bactericide that can effectively inhibit the growth of molds, yeasts, and bacteria. The combined use of MIT and 1,2-benzisothiazolin-3-one can broaden the antibacterial spectrum, synergistically improve the preservative effect, and ensure the storage stability and safety of the product.

[0034] In embodiments of the present invention, the scratch-resistant matte oil for black substrates further includes 0.1 to 0.3 parts of defoamer. Exemplarily, the defoamer may be a polyether siloxane copolymer, such as at least one of BYK-021, BYK-022, Tego902w, and Tego833.

[0035] This invention also proposes the application of the scratch-resistant matte oil for black substrates as described in the foregoing technical solution in the preparation of outer packaging materials, comprising the following steps: A black substrate is provided, and the scratch-resistant matte varnish for the black substrate described in the aforementioned technical solution is printed on the black substrate. After drying, the outer packaging material is obtained.

[0036] The scratch-resistant matte varnish for black substrates provided by this invention is simple to use and easy to implement. It can be directly printed onto the black substrate using conventional printing processes. For example, the scratch-resistant matte varnish can be printed using a screen printing machine with a 200-300 mesh screen, or using a 110-line anilox roller coating method. After the matte varnish is fully dried, it achieves a silky smooth feel, good scratch resistance, and a low blackness value.

[0037] It should be noted that the present invention can be used directly on a black substrate with the provided anti-scratch matte varnish for black substrates, or the provided anti-scratch matte varnish for black substrates can be printed after black is coated on a transparent / white substrate.

[0038] It should be noted that when actually using the anti-scratch matte varnish for black substrates, in order to quickly achieve an emissivity of less than 3.5% and a blackness value (L) of less than 25, the following specifications of black substrate can be selected: the black substrate has a reflectivity of less than 10% and a blackness value (L) of less than 28. Using the above-mentioned specifications of black substrate, and then using the anti-scratch matte varnish provided by this invention, is beneficial to achieve an ink layer with a reflectivity of less than 3.5%, a blackness value (L) of less than 25, and an anti-scratch resistance of more than 1000 times (4-pound load, 4-speed back-and-forth friction test). In actual operation, if the substrate color is sufficiently black, the anti-scratch matte varnish provided by this invention can be printed directly; if the substrate's L value is not black enough, the anti-scratch matte varnish provided by this invention can be printed after applying more black ink.

[0039] In embodiments of the present invention, the printing thickness of the scratch-resistant matte varnish for the black substrate is 5-8 μm. If the coating thickness is too low (e.g., 2-3 μm), the black ink layer may not be fully covered on the coating surface, resulting in an uneven coating surface after printing. If the coating is too thick, its fluidity is too high, and it may not dry and set in time during the coating process, also easily leading to uneven coating thickness. It should be noted that, in this document, the printing thickness of the scratch-resistant matte varnish for the black substrate being 5-8 μm refers to the dry film thickness of the matte varnish after printing being 5-8 μm.

[0040] In an embodiment of the present invention, in the step of drying the anti-scratch matte oil, the drying temperature is 80~100℃ and the drying time is 60~180s. Exemplarily, the drying temperature can be 80℃, 85℃, 90℃, 95℃ or 100℃, and the drying time can be 60s, 90s, 120s, 150s or 180s.

[0041] The present invention also proposes an outer packaging material, wherein the outer packaging material comprises the scratch-resistant matte oil for black substrate as described in the foregoing technical solution, or the outer packaging material is obtained by the application described in the foregoing technical solution.

[0042] It should be noted that, in this article, the outer packaging material refers to products such as packaging films, packaging papers, and packaging boxes with the scratch-resistant matte oil for black substrates provided by this invention coated or printed on their surfaces, such as inner labels for electronic product lenses and decorative labels for packaging boxes.

[0043] In an embodiment of the present invention, the reflectivity of the outer packaging material is less than 3.5%, and the blackness value L is less than 25.

[0044] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0045] In the following embodiments, the resin used is waterborne polyurethane resin, CAS 68400-67-9; All the hand-feeling agents are made of polysiloxane, CAS 63148-62-9; The bactericides include methylisothiazolinone (CAS 3682-20-4) and 1,2-benzisothiazolin-3-one (CAS 26344-33-5). The matte powder is selected from fumed silica, CAS 7631-86-9.

[0046] Example 1 This embodiment provides a scratch-resistant matte oil for black substrates, wherein the scratch-resistant matte oil for black substrates comprises the following components by weight: The mixture contains 30 parts of waterborne polyurethane resin, 50 parts of deionized water, 3 parts of silica, 0.01 parts of polysiloxane, 0.01 parts of methylisothiazolinone, and 0.01 parts of 1,2-benzisothiazolin-3-one.

[0047] The method for preparing the scratch-resistant matte oil for black substrates includes the following steps: (1) Mix deionized water and waterborne polyurethane resin, heat to 45°C and stir at 2000 rpm. After the waterborne polyurethane resin is completely dissolved, add silica, polysiloxane, methylisothiazolinone, and 1,2-benzisothiazolin-3-one, and disperse and stir for 5 min. (2) Adjust the pH to 7.5~8.5 with stirring, and filter to obtain the product.

[0048] Example 2 This embodiment provides a scratch-resistant matte oil for black substrates, wherein the scratch-resistant matte oil for black substrates comprises the following components by weight: The mixture contains 32 parts of waterborne polyurethane resin, 55 parts of deionized water, 4 parts of silica, 0.5 parts of polysiloxane, 0.2 parts of methylisothiazolinone, and 0.5 parts of 1,2-benzisothiazolin-3-one.

[0049] Example 3 This embodiment provides a scratch-resistant matte oil for black substrates, wherein the scratch-resistant matte oil for black substrates comprises the following components by weight: The mixture consists of 35 parts waterborne polyurethane resin, 60 parts deionized water, 5 parts silica, 1 part polysiloxane, 0.5 parts methylisothiazolinone, and 1 part 1,2-benzisothiazolin-3-one.

[0050] Example 4 The difference compared to Example 2 is that the amount of silica used is 4.5 parts.

[0051] Example 5 The difference compared to Example 2 is that the amount of silica used is 5 parts.

[0052] Example 6 Compared to Example 2, the difference is that it also includes 0.2 parts of defoamer (BYK-021).

[0053] Example 7 This embodiment provides an application of the aforementioned scratch-resistant matte oil for black substrates in the preparation of outer packaging materials, including the following steps: (1) Provide 50# black glue-free PET as black substrate (Jinlibao's 50# black glue-free PET). (2) The scratch-resistant matte varnish for black substrates of Example 2 is printed on the black substrate (using gravure printing process, using an anilox roller with 110 lines / inch for coating), and the coated substrate is sent into a hot air circulating oven for drying. After drying, the outer packaging material is obtained; wherein, the drying temperature is 90°C, the drying time is 120s, and the printing thickness of the scratch-resistant matte varnish for black substrates is 5~8µm (the measured average dry film thickness is 6.5µm).

[0054] Performance testing To confirm whether adjusting the black ink and matte oil formulations could achieve a surface reflectance of less than 3.5% and a blackness value (L value) of less than 25, different commercially available black ink formulations and matte oils were applied to the same substrate. The surface blackness value (L value) and reflectance were then measured using a 2600D colorimeter in D65 / 10 and SCI mode, and the luminance value (GU value) was measured using a gloss meter.

[0055] The following tests were conducted: Table 1 Performance test results using different commercially available black ink formulations

[0056] Table 2 Performance test results using different commercially available black ink formulations and mattes

[0057] The test results in Tables 1 and 2 show that it is difficult to achieve a reflectivity of less than 3.5% and a blackness value (L value) of less than 25 on the surface of the ink layer by adjusting the black ink formula and the matte ink formula.

[0058] To further verify that the scratch-resistant matte varnish provided by this invention can simultaneously achieve a reflectance of less than 3.5%, a blackness value (L value) of less than 25, and good scratch resistance on the surface of the printed ink layer, the low-matteness and scratch resistance properties of the scratch-resistant matte varnishes of Examples 1-6 were tested. Following the application method of Example 7, the scratch-resistant matte varnishes of Examples 1-6 were used to make outer packaging materials. Then, a 2600D colorimeter was used to test the surface blackness value (L value) and reflectance in D65 / 10, SCI mode, and the luminance value (GU value) was tested using a gloss meter. Simultaneously, the scratch resistance of the ink surface was tested (4-pound load, 4-speed back-and-forth friction test). The test results are shown in Table 3. In Groups 1-12, adhesive-free PET was used as the base material. Groups 1-6 used the same type of base material, and Groups 7-12 used the same type of base material. The difference between the base materials used in Groups 1-6 and Groups 7-12 was the blackness value, reflectance, and reflectance.

[0059] Table 3. Test results of low-matte performance of anti-scratch matte oils in Examples 1-6

[0060] As shown in the test results of groups 7-12 in Table 3, the anti-scratch matte ink provided by this invention can achieve a surface reflectance of less than 3.5%, a blackness value (L) of less than 25, and good anti-scratch performance after printing on a black substrate. Furthermore, the test results of groups 1-6 and 7-12 in Table 3 show that using a substrate with a reflectance of less than 10% and a blackness value (L) of less than 28 is more conducive to achieving a surface reflectance of less than 3.5% and a blackness value (L) of less than 25. In addition, according to the results of groups 2, 4, and 5, as the amount of matte powder increases, the test results for reflectance and blackness value (L) both show a decreasing trend.

[0061] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A scratch-resistant matte oil for black substrates, characterized in that, By weight, it includes the following components: 30-35 parts of water-based matte resin, 50-60 parts of solvent, 3-5 parts of matting powder, and 0.01-1 parts of hand feel agent; The waterborne matte resin is a waterborne polyurethane resin.

2. The scratch-resistant matte oil for black substrates as described in claim 1, characterized in that, The coating formed after curing of the waterborne polyurethane resin has a gloss level of <10 GU at a 60° angle.

3. The scratch-resistant matte oil for black substrates as described in claim 1, characterized in that, The solvent includes deionized water; and / or, The tactile agent includes polysiloxane; and / or, The matte powder comprises fumed silica; and / or, The substrate material of the black substrate includes at least one of polycarbonate, polyethylene, and polyethylene terephthalate.

4. The scratch-resistant matte oil for black substrates as described in claim 1, characterized in that, The scratch-resistant matte oil for black substrates also includes 0.02 to 1.5 parts of bactericide.

5. The scratch-resistant matte oil for black substrates as described in claim 4, characterized in that, The bactericide includes at least one of methylisothiazolinone and 1,2-benzisothiazolin-3-one.

6. The scratch-resistant matte oil for black substrates as described in claim 4, characterized in that, The scratch-resistant matte oil for black substrates also includes 0.1 to 0.3 parts of defoamer.

7. The application of a scratch-resistant matte oil for a black substrate as described in any one of claims 1 to 6 in the preparation of outer packaging materials, characterized in that, Includes the following steps: A black substrate is provided, and the scratch-resistant matte varnish for the black substrate as described in any one of claims 1 to 6 is printed on the black substrate, and the outer packaging material is obtained after drying.

8. The application as described in claim 7, characterized in that, The black substrate has a reflectance of less than 10% and a blackness value L of less than 28; and / or, The printing thickness of the scratch-resistant matte varnish used on the black substrate is 5~8μm.

9. An outer packaging material, characterized in that, The outer packaging material comprises the scratch-resistant matte oil for a black substrate as described in any one of claims 1 to 6, or the outer packaging material is obtained by the application described in claim 7 or 8.

10. The outer packaging material as described in claim 9, characterized in that, The outer packaging material has a reflectivity of less than 3.5% and a blackness value L of less than 25.

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