Preparation method of high-thickness silica gel transfer mark

Abstract

The invention discloses a preparation method of a high-thickness silica gel transfer mark, which comprises the following steps: S1, preparing a digital printing bottom layer film: S11, coating a cold tearing resin release agent on a base material to prepare a release base material; s12, coating a wear-resistant layer on the release base material; s13, the wear-resistant layer is coated with a bottom coating; s14, performing corona on the bottom coating, and then digitally printing a pattern on the bottom coating; s15, the digital printing pattern is coated with a silica gel layer; s2, preparing a middle-layer adhesive film; s3, locking a mold on the middle-layer adhesive film, wherein the mold is provided with hollows corresponding to the patterns; s4, silica gel is added into the hollowed-out part of the mold, then the silica gel is covered with the digital printing bottom layer film, and the digital printing pattern is aligned to the mold; and S5, carrying out vulcanization molding on the silica gel. The prepared silica gel transfer printing mark is high in thickness, does not have the condition of glue overflowing at the edge, and has wear resistance and washing resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone transfer labeling, and particularly to a method for preparing high-thickness silicone transfer labels. Background Art

[0002] In the existing preparation process of silicone transfer labels, liquid silicone is mostly directly coated or screen printed multiple times until the silicone transfer label reaches the required thickness.

[0003] For example, Chinese Patent with publication number CN109334293A discloses a method for preparing a heat-transferable silicone transfer label, which includes the following steps: Step 1, uniformly mixing an addition-curable liquid silicone, a color paste, and a curing agent to obtain a printing silicone; Step 2, printing the printing silicone on a release film, drying it each time after printing, and then printing the next time until the required thickness is reached; Step 3, preparing a bridging agent; Step 4, printing the uniformly prepared bridging agent on the surface of the product obtained above, and baking it dry each time; Step 5, adding a diluent to the hot melt adhesive, stirring evenly, printing on the front surface of the product in Step 4, and leaving it to stand; Step 6, placing the above product in a multi-layer rack, putting it into an oven, controlling the temperature and time to obtain a silicone transfer label; Step 7, hot stamping on both sides.

[0004] Preparing silicone transfer labels by printing liquid silicone multiple times faces many technical problems, mainly including: when the silicone thickness exceeds 0.3 mm, at least 10 or more printings are required. Moreover, as the silicone thickness increases and the silicone layer is relatively soft, there will be situations such as printing position deviation and edge glue overflow, which affect the quality of the silicone transfer label. And performing multiple printings has cumbersome steps.

[0005] In view of this, the present invention proposes a method for preparing high-thickness silicone transfer labels to solve the above problems. Summary of the Invention

[0006] In order to overcome the above-mentioned deficiencies in technology, the present invention provides a method for preparing high-thickness silicone transfer labels. By optimizing the preparation process flow, using digital printing technology to achieve precise transfer of patterns, and combining mold design and vulcanization molding technology, high-thickness, high-wear-resistant, clearly patterned, and quality-stable silicone transfer labels are successfully prepared.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing high-thickness silicone transfer labels, comprising the following steps:

[0009] S1: Prepare the digital printing bottom film, including: S11: Coat a cold-peelable resin release agent on a substrate to obtain a release substrate; S12: Coat an abrasion-resistant layer on the release substrate; S13: Coat a primer layer on the abrasion-resistant layer; S14: Corona-treat the primer layer and then digitally print a pattern on the primer layer; S15: Coat a silica gel layer on the digitally printed pattern;

[0010] S2: Prepare the middle-layer film;

[0011] S3: Lock the mold on the middle-layer film. The mold is provided with a hollow corresponding to the pattern;

[0012] S4: Add silica gel into the hollow of the mold, then cover the digital printing bottom film on the silica gel, and align the digitally printed pattern with the mold;

[0013] S5: Vulcanize the silica gel into a mold;

[0014] S6: Cut out the excess digital printing bottom film and middle-layer film.

[0015] Preferably, in S2, the middle-layer film is formed by coating silica gel on a film.

[0016] Preferably, the film is one of TPU, PA, and PU films.

[0017] Preferably, the thickness of the silica gel in the mold is greater than 0.1 mm.

[0018] Preferably, the substrate is CPP.

[0019] Preferably, the abrasion-resistant layer includes acrylic resin and polyethylene wax, and the thickness is 0.001 - 0.01 mm.

[0020] Preferably, the primer layer includes a polyurethane copolymer, and the thickness is 0.001 - 0.01 mm.

[0021] Preferably, in S3, the middle-layer film is placed on a workbench, and multiple molds are placed on the middle-layer film. The molds are fixedly connected to each other, and the mold near the edge of the middle-layer film is fixedly connected to the workbench, and the mold is tightly pressed on the middle-layer film.

[0022] Preferably, in S4, after the digital printing bottom film covers the silica gel, a cover plate is covered above the digital printing bottom film, and then vulcanization is carried out.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. In the present invention, the mold is locked on the middle layer film, and silica gel is added into the mold. The digital printing bottom layer film covers the silica gel, and then the silica gel is vulcanized and formed. Under the limitation of the mold, there will be no overflow of the glue at the edge of the transfer mark. Compared with the traditional method of preparing silica gel transfer marks by multiple printing, in the present invention, silica gel is added into the mold at one time and then vulcanized and formed, which is more suitable for preparing high-thickness silica gel transfer marks. There is no need to repeat the silica gel printing multiple times, which not only simplifies the preparation steps but also avoids the problem of position deviation caused by repeated printing.

[0025] 2. The present invention uses digital printing technology to directly print patterns on the bottom coating layer. Compared with the traditional printing process, digital printing has higher precision and flexibility, and can achieve accurate transfer of complex patterns, gradient colors, and tiny characters.

[0026] 3. Both the digital printing bottom layer film and the middle layer film are coated with silica gel. During the vulcanization process, the silica gel on the digital printing bottom layer film, the silica gel in the mold, and the silica gel on the middle layer film are cross-linked, so that the digital printing bottom layer film, the middle silica gel, and the middle layer film are firmly combined. Specifically, the digital printing bottom layer film further includes a wear-resistant layer, which can protect the digital printing pattern and the middle silica gel. The film is one of TPU, PA, and PU films, which can improve the overall water-wash resistance of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of a high-thickness silica gel transfer mark prepared by using the present invention;

[0028] Figure 2 is a schematic diagram of the digital printing bottom layer film and the mold using the present invention;

[0029] The implementation, functional features, and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following further details the features of the present invention and other related features through embodiments for the understanding of those skilled in the same industry:

[0031] As Figures 1-2 shown, the embodiment of the present invention provides a method for preparing a high-thickness silica gel transfer mark, including the following steps:

[0032] S1: Prepare the digital printing bottom layer film 7, including: S11: Coat the cold tear resin release agent 72 on the substrate 71 to obtain a release substrate; S12: Coat the wear-resistant layer 73 on the release substrate; S13: Coat the bottom coating layer 74 on the wear-resistant layer 73; S14: Corona the bottom coating layer 74 and then digitally print the pattern 75 on the bottom coating layer 74; S15: Coat the silica gel layer 76 on the digital printing pattern 75;

[0033] S2: Prepare the middle layer film 9;

[0034] S3: Lock the mold 91 on the middle layer film 9. The mold 91 is provided with a hollow corresponding to the pattern 75;

[0035] S4: Add silicone 8 into the hollow of the mold 91, then cover the digital printing bottom film 7 on the silicone 86, and align the digital printing pattern 75 with the mold 91;

[0036] S5: Vulcanize the silicone into a mold;

[0037] S6: Cut out the redundant digital printing bottom film 7 and middle layer film 9.

[0038] In some embodiments, S2 forms the middle layer film 9 by coating silicone 92 on the film 93.

[0039] In some embodiments, the film 93 is one of TPU, PA, and PU films.

[0040] In some embodiments, the thickness of the silicone in the mold 91 is greater than 0.1 mm.

[0041] In some embodiments, the substrate 71 is CPP.

[0042] In some embodiments, the wear-resistant layer 73 includes acrylic resin and polyethylene wax, and the thickness is 0.001 - 0.01 mm.

[0043] In some embodiments, the bottom coating 74 includes a polyurethane copolymer, and the thickness is 0.001 - 0.01 mm, which can increase the interfacial adhesion of the wear-resistant layer 73 and facilitate the adhesion of digital ink.

[0044] In some embodiments, in S3, the middle layer film 9 is placed on the workbench, and a plurality of molds 91 are placed on the middle layer film 9. The molds 91 are fixedly connected to each other. The mold 91 near the edge of the middle layer film 9 is fixedly connected to the workbench, and the mold 91 is tightly pressed on the middle layer film 9.

[0045] In some embodiments, in S4, the digital printing bottom film 7 is covered on the silicone, and then a cover plate is covered above the digital printing bottom film 7, so that the silicone of the digital printing bottom film 7 fits the silicone in the mold 91, and then vulcanization is carried out.

[0046] In some embodiments, the mold 91 is made of copper material, which has good thermal conductivity and is beneficial to the formation of vulcanized silicone.

[0047] Example 1 provides a silicone transfer label, and its preparation method includes the following steps:

[0048] S11: Coating a cold-peel resin release agent 72 on the CPP substrate, and drying it to obtain a release substrate.

[0049] S12: Coating a mixture of acrylic resin and polyethylene wax on the release substrate, where the mass ratio of acrylic resin to polyethylene wax in the mixture is 1:10, and drying it to form a wear-resistant layer with a thickness of 0.005 mm.

[0050] S13: Coating a primer solution containing a polyurethane copolymer on the wear-resistant layer, and drying it to form a primer layer with a thickness of 0.005 mm.

[0051] S14: After corona treating the primer layer with 800 - 1200 W, printing a pattern on the primer layer by digital printing.

[0052] S15: Coating a silica gel layer with a thickness of 0.005 mm on the digitally printed pattern.

[0053] S2: Coating silica gel on the TPU film to form an intermediate film.

[0054] S3: Placing the intermediate film on the workbench, placing multiple molds on the intermediate film. The molds are provided with cutouts corresponding to the pattern. The molds are fixedly connected to each other, and the molds near the edge of the intermediate film are fixedly connected to the workbench, and the molds are tightly pressed on the intermediate film.

[0055] S4: Adding silica gel with a thickness of 0.3 mm into the cutouts of the molds, and then covering the digitally printed bottom film on the silica gel, and aligning the digitally printed pattern with the molds.

[0056] S5: Covering a cover plate above the digitally printed bottom film, so that the silica gel of the digitally printed bottom film fits the silica gel in the molds, and then performing vulcanization. Vulcanization conditions: 150 °C, vulcanization time 400 s.

[0057] S6: Cutting out the excess digitally printed bottom film and intermediate film.

[0058] Example 2 provides a silica gel transfer label. Its preparation method is the same as that of Example 1 except that the thickness of the silica gel added into the molds in S4 is 0.4 mm, vulcanization conditions: 165 °C, vulcanization time 530 s.

[0059] Comparative Example 1 provides a silica gel transfer label. Its preparation method includes S11 - 14 of Example 1 to obtain a digitally printed bottom film; then printing silica gel on the digitally printed bottom film by silk screen, drying it each time after printing, and then printing the next time until the thickness of the silica gel layer reaches 0.3 mm.

[0060] Comparative Example 2 provides a silicone transfer label. The preparation method is the same as that of Example 1 except that a silicone layer with a thickness of 0.005 mm is not coated on the digital printing bottom film, and the TPU film is directly covered on the mold without coating silicone.

[0061] Performance Test

[0062] I. Observe the edge of the silicone transfer label under a microscope and calculate the edge overflow rate = the area of the overflow area / the area of the standard silicone transfer label × 100%.

[0063] II. Test the peel strength between the digital printing bottom film and the silicone layer according to the GB / T 2792 standard.

[0064] III. Test the water wash resistance of the silicone transfer label according to the AATCC 135 standard.

[0065] Table 1 Performance test results of Examples 1-2 and Comparative Examples 1-2

[0066] Item Edge Glue Spill Rate Peel Strength (N / cm) Number of Wash Cycles Resistant Example 1 0 15.2 > 50 cycles without detachment Example 2 0 15.4 > 50 cycles without detachment Comparative Example 1 9.5％ 9.5 Local cracking after 30 cycles Comparative Example 2 0 6.3 Delamination after 20 cycles

[0067] (1) From the above test results, it can be seen that in Comparative Example 1, by screen-printing silicone on the digital printing bottom film multiple times to form a silicone transfer label with a thickness of 0.3 mm, there will be a situation of overflow at the edge. This is because silicone has fluidity, and as the thickness of the silicone increases and the silicone layer is relatively soft, there will be a deviation in the printing position. In Examples 1-2, by locking the mold on the middle film and then injecting glue into the mold, the situation of edge overflow can be avoided.

[0068] (2) By comparing Examples 1-2 with Comparative Example 2, it can be seen that the connection strength between the coated digital printing bottom film and the high-thickness silicone layer (i.e., the silicone in the mold) is good. This is because the silicone on the digital printing bottom film and the high-thickness silicone layer undergo an addition reaction at the interface during the vulcanization process, forming a Si-C-Si covalent bond network, which makes the silicone completely crosslinked into one body.

[0069] (3) By comparing Examples 1-2 with Comparative Examples 1-2, it can be seen that the middle film and the digital printing bottom film can improve the water wash resistance of the silicone transfer label.

[0070] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A preparation method for high-thickness silicone transfer marks, characterized in that, Including the following steps S1: Prepare the digital printing bottom film, including: S11: Coat a cold tear resin release agent on the substrate to obtain a release substrate; S12: Coat an abrasion-resistant layer on the release substrate; S13: Coat a primer layer on the abrasion-resistant layer; S14: After corona treating the primer layer, digitally print a pattern on the primer layer; S15: Coat a silica gel layer on the digitally printed pattern; S2: Prepare the middle layer film; S3: Lock the mold on the middle layer film, and the mold is provided with a hollow corresponding to the pattern; S4: Add silica gel into the hollow of the mold, then cover the digital printing bottom film on the silica gel, and align the digitally printed pattern with the mold; S5: Vulcanize the silica gel into a mold; S6: Cut out the excess digital printing bottom film and middle layer film.

2. The preparation method of a high-thickness silicone transfer label according to claim 1, wherein In S2, the middle layer film is formed by coating silica gel on the film.

3. A method for preparing a high-thickness silicone transfer label according to claim 1, characterized in that, The film is one of TPU, PA, and PU films.

4. A method for preparing a high-thickness silicone transfer label according to claim 1, characterized in that The thickness of the silica gel in the mold is greater than 0.1 mm.

5. A method for preparing a high-thickness silicone transfer label according to claim 1, characterized in that, The substrate is CPP.

6. A method for preparing a high-thickness silicone transfer label according to claim 1, characterized in that, The abrasion-resistant layer includes acrylic resin and polyethylene wax, and the thickness is 0.001 - 0.01 mm.

7. A method for preparing a high-thickness silicone transfer label according to claim 1, characterized in that, The primer layer includes polyurethane copolymer, and the thickness is 0.001 - 0.01 mm.

8. A method for preparing a high-thickness silicone transfer label according to claim 1, wherein, In S3, the middle layer film is placed on the workbench, multiple molds are placed on the middle layer film, the molds are fixedly connected to each other, the mold near the edge of the middle layer film is fixedly connected to the workbench, and the mold is tightly pressed on the middle layer film.

9. A method for preparing a high-thickness silicone transfer label according to claim 1, characterized in that, In S4, the digital printing bottom film is covered on the silica gel, then a cover plate is covered above the digital printing bottom film, and then vulcanization is carried out.

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