Production process of transparent composite positioning frame

Abstract

The invention discloses a production process of a transparent composite positioning frame, which comprises the following steps: (1) taking a modified PBT (Polybutylece Terephthalate) base material as a substrate layer, uniformly coating siloxane-polyurethane hybrid primer on the modified PBT base material, and curing to form a siloxane-polyurethane hybrid primer layer; (2) uniformly coating the siloxane-polyurethane hybrid primer layer with a nano aluminum oxide dispersion liquid, and curing to form a nano aluminum oxide dispersion coating; (3) UV ink is printed on the nanometer aluminum oxide dispersion I coating, UV curing is carried out, and an ink layer is formed; and (4) hot stamping foil is placed on the ink layer, heating and pressurizing are carried out, so that the metal layer of the hot stamping foil is transferred to the surface of the ink, a hot stamping layer is formed, and post-heat treatment is carried out. According to the transparent PBT positioning frame paper produced by the invention, the supporting force of the frame paper can be improved, and the problems of insufficient rigidity, poor wear resistance or low ink adhesion during common printing are solved.

Description

Technical Field

[0001] This invention relates to a manufacturing process for a transparent composite positioning frame, belonging to the field of packaging and printing technology. Background Technology

[0002] In the packaging and printing industry, traditional positioning frames typically use paper as the substrate. However, paper substrates suffer from insufficient rigidity and weak support, leading to positioning misalignment during printing and significantly impacting printing accuracy. Furthermore, traditionally used inks exhibit poor adhesion, often causing printed patterns to peel off or become blurred. Their poor surface abrasion resistance also makes the positioning frame easily scratched during frequent use, shortening its lifespan and reducing print quality. To address these issues, existing technologies have employed two approaches: first, thickening the paper frame to increase rigidity, but this reduces light transmittance and increases weight; second, coating the paper frame surface with ordinary protective paint, but the paint's abrasion resistance and ink adhesion remain poor. Therefore, this invention provides a manufacturing process for a transparent composite positioning frame that meets the multiple requirements of high-precision printing. Summary of the Invention

[0003] At least to address one of the problems existing in the prior art, the present invention provides a production process for a transparent composite positioning frame, which can improve the support strength of the frame paper, meet the multiple requirements of high-precision printing, and solve the problems of insufficient rigidity, poor wear resistance, or low ink adhesion in ordinary printing.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a manufacturing process for a transparent composite positioning frame, comprising the following steps: (1) Using modified PBT substrate as base layer, first uniformly apply siloxane-polyurethane hybrid primer on modified PBT substrate and cure to form siloxane-polyurethane hybrid primer layer. (2) The nano-alumina dispersion is uniformly coated on the siloxane-polyurethane hybrid primer layer and cured to form a nano-alumina dispersion coating. (3) Print UV ink onto the nano-alumina dispersion I coating, and cure with UV to form an ink layer; (4) Place the hot stamping foil on the ink layer, heat and pressurize it to transfer the metal layer of the hot stamping foil to the ink surface to form a hot stamping layer, and then heat treat it.

[0005] Preferably, the production process further includes step (5): spraying the prepared water-based polyurethane wear-resistant liquid onto the ink layer, curing it to form a water-based polyurethane wear-resistant coating, and finally heat-treating it. When performing step (5), the hot stamping layer formed in step 4 is not heat-treated.

[0006] Preferably, in step (1), the modified PBT substrate is prepared from PBT, nanofillers, silane coupling agents and auxiliary raw materials, wherein the silane coupling agent modifies the surface of the nanofillers.

[0007] Preferably, in step (1), the thickness of the modified PBT substrate is 0.3±0.02mm.

[0008] Preferably, the amount of nanofiller added is 9-12 wt% of the weight of PBT, the amount of silane coupling agent added is 0.8-1.5 wt% of the weight of nanofiller, and the amount of additive is 0.5-1 wt% of the weight of PBT.

[0009] Preferably, the nanofiller is composed of nanosilicate and nanocellulose mixed in a ratio of 2:2 to 3.

[0010] Preferably, the silane coupling agent is one or both of A-174 and KH-570.

[0011] Preferably, in step (1), the siloxane-polyurethane hybrid primer is prepared from hydroxyl-terminated polysiloxane, a polyurethane prepolymer containing 5.5% NCO, ethyl acetate, and the catalyst DBTDL; wherein, the polyurethane prepolymer containing 5.5% NCO is generated by the reaction of isophorone diisocyanate and polyether polyol with the catalyst DBTDL.

[0012] Preferably, in the siloxane-polyurethane hybrid primer, the content of polysiloxane with hydroxyl end caps is 30 wt%, the content of ethyl acetate is 4.5~7 wt%, the content of catalyst DBTDL is 0.5 wt%, and the remainder is a polyurethane prepolymer containing 5.5% NCO.

[0013] Preferably, in step (1), the polysiloxanes with hydroxyl end caps are selected from either dihydroxyl-terminated polydimethylsiloxane or hydroxypropyl-terminated polydimethylsiloxane.

[0014] Preferably, in step (2), the nano-alumina dispersion is prepared from nano-α-alumina, silane coupling agent, anionic lignin sulfonate, polyurethane resin and ethanol aqueous solution as raw materials, wherein the silane coupling agent modifies the surface of the nano-α-alumina.

[0015] Preferably, in the nano-alumina dispersion, the content of nano-α-alumina is 20~25wt%, the content of polyurethane resin is 4~8wt%, the content of anionic lignin sulfonate is 0.5~1%, and the silane coupling agent is 0.8~1.5wt% of nano-α-alumina.

[0016] Preferably, in step (3), the UV ink is an ink that is a mixture of acrylate system and polyurethane acrylate.

[0017] Preferably, in the UV ink, the content of acrylate system is 25~30wt%, and the content of polyurethane acrylate is 30~35wt%.

[0018] Preferably, the acrylate system is an epoxy acrylate.

[0019] Preferably, in step (5), the waterborne polyurethane wear-resistant liquid is prepared from nano-α-alumina, nano-zinc oxide, silane coupling agent, anionic lignin sulfonate, polyurethane resin and ethanol aqueous solution, wherein the silane coupling agent modifies the surface of nano-α-alumina and nano-zinc oxide.

[0020] Preferably, in the aqueous polyurethane wear-resistant fluid, the content of nano-α-alumina is 2~6wt%, nano-zinc oxide is 5~10%, polyurethane resin is 10~15wt%, anionic lignin sulfonate is 0.5~1%, and silane coupling agent is 0.8~1.5wt% of the sum of nano-α-alumina and nano-zinc oxide.

[0021] Preferably, the anionic lignin sulfonate is calcium lignin sulfonate, sodium lignin sulfonate, magnesium lignin sulfonate, etc., with calcium lignin sulfonate being the most preferred.

[0022] Preferably, in step (4), the heating and pressurization conditions are: temperature 105~135℃, pressure 0.2~0.5MPa, and time 1~2s.

[0023] Preferably, in step (4) or (5), the heat treatment conditions are: heating to 85-95°C at 1-2°C / min, holding at 50-70 min, and then cooling down at 1-2°C / min.

[0024] Preferably, in step (5), the thickness of the waterborne polyurethane wear-resistant coating is 0.5~1μm.

[0025] The beneficial effects of the present invention are as follows: (1) The present invention uses biodegradable PBT material to replace paper base, and improves longitudinal rigidity through molecular orientation regulation, thereby enhancing the support and transparency of the product, allowing the internal structure of the product to be seen, making it more beautiful and more environmentally friendly; at the same time, the PBT material is modified by nanofillers, further improving the rigidity and toughness of the transparent PBT positioning frame paper. (2) The present invention uses a double-layer base coat of siloxane-polyurethane hybrid primer and nano-alumina dispersion coating, which improves the ink adhesion and color layer abrasion resistance during printing, and at the same time improves the scratch resistance of the product during transportation; at the same time, the nano-alumina dispersion coating also promotes the improvement of the rigidity of the transparent PBT positioning frame paper. (3) The UV ink used in the present invention is an ink that is a mixture of acrylic ester system and polyurethane acrylate, which makes the printed pattern present a three-dimensional effect, and at the same time improves the adhesion between ink and coating.

[0026] (4) The present invention sprays a thin layer of water-based polyurethane wear-resistant coating on the ink layer, which further improves the rigidity, toughness and wear resistance of the product, and can enhance the adhesion of the hot stamping layer, reduce the risk of hot stamping layer falling off, and also improve the ultraviolet shielding, greatly extending the service life.

[0027] (1) The transparent PBT positioning frame paper produced by this invention has the characteristics of high precision and high durability. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. The described embodiments are only a part of the embodiments of the present invention, and not all of them. 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents, instruments, or components are not specified, they are all conventional products that can be purchased commercially.

[0029] Example 1: Preparation of Modified PBT Substrate Example 1.1 Modified PBT substrate, denoted as A1, is prepared as follows: a1. Dissolve A-174 (vinyltrimethoxysilane) in 90% ethanol aqueous solution to form a 2wt% A-174 silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 5-8 minutes. Then add a nanofiller composed of nanosilicate and nanocellulose mixed in a 2:2 ratio. Stir at 1000-1500 rpm for 30 minutes to allow silane molecules to be uniformly adsorbed on the surface of the filler. Then dry to remove the solvent to obtain the surface-modified nanofiller. a2. Surface-modified nanofiller, PBT (polybutylene terephthalate), antioxidant 1010 and lubricant EBS are mixed, extruded and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm±0.02mm to obtain modified PBT substrate. The amount of nanofiller added is 10.5 wt% of PBT weight, the amount of A-174 added is 1 wt% of nanofiller weight, the amount of antioxidant 1010 is 0.5 wt% of PBT weight, and the amount of lubricant EBS compounded is 0.4 wt% of PBT weight.

[0030] Example 1.2 Modified PBT substrate, denoted as A2, is prepared as follows: a1. Dissolve KH-570 (methacryloyloxypropyltrimethoxysilane) in 90% ethanol aqueous solution to form a 2wt% KH-570 silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-silicate and nano-cellulose mixed in a ratio of 2:2.5 to form a nanofiller. Stir at 1000-1500 rpm for 30 min to allow silane molecules to be uniformly adsorbed on the surface of the filler. Then dry to remove the solvent to obtain the surface-modified nanofiller. a2. Surface-modified nanofiller, PBT, antioxidant 1010 and lubricant EBS are mixed and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm±0.02mm to obtain modified PBT substrate. The amount of nanofiller added is 9 wt% of PBT weight, the amount of KH-570 added is 0.8 wt% of nanofiller weight, the amount of antioxidant 1010 is 0.5 wt% of PBT weight, and the amount of lubricant EBS compounded is 0.3 wt% of PBT weight.

[0031] Example 1.3 Modified PBT substrate, denoted as A3, was prepared as follows: a1. Dissolve A-174 in 90% ethanol aqueous solution to form 2wt% A-174 silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 5-8 minutes. Then add nanofiller composed of nanosilicate and nanocellulose mixed in a 2:3 ratio. Stir at 1000-1500 rpm for 30 minutes to make silane molecules uniformly adsorbed on the surface of the filler. Then dry to remove the solvent and obtain surface modified nanofiller. a2. Surface-modified nanofiller, PBT, antioxidant 1010 and lubricant EBS are mixed and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm±0.02mm to obtain modified PBT substrate. The amount of nanofiller added is 12 wt% of PBT weight, the amount of A-174 added is 1.5 wt% of nanofiller weight, the amount of antioxidant 1010 is 0.3 wt% of PBT weight, and the amount of lubricant EBS compounded is 0.3 wt% of PBT weight.

[0032] Example 1.4 Modified PBT substrate, denoted as A4, was prepared using the following process: a1. Dissolve A-174 in 90% ethanol aqueous solution to form 2wt% A-174 silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 5-8 min. Then add single nanofiller nanosilicate and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. Then dry to remove the solvent and obtain surface modified nanofiller. a2. Surface-modified nanofiller, PBT, antioxidant 1010 and lubricant EBS are mixed and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm±0.02mm to obtain modified PBT substrate. The amount of nano-silicate added is 10.5 wt% of PBT weight, the amount of A-174 added is 1 wt% of nano-silicate weight, the amount of antioxidant 1010 is 0.5 wt% of PBT weight, and the amount of lubricant EBS compounded is 0.4 wt% of PBT weight.

[0033] Example 1.5 Modified PBT substrate, denoted as A5, was prepared as follows: a1. Dissolve A-174 in 90% ethanol aqueous solution to form 2wt% A-174 silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 5-8 min. Then add single nanofiller nanocellulose and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. Then dry to remove the solvent and obtain surface modified nanofiller. a2. Surface-modified nanofiller, PBT, antioxidant 1010 and lubricant EBS are mixed and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm±0.02mm to obtain modified PBT substrate. The amount of nanocellulose added is 10.5 wt% of PBT weight, the amount of A-174 added is 1 wt% of nanocellulose weight, the amount of antioxidant 1010 is 0.5 wt% of PBT weight, and the amount of lubricant EBS compounded is 0.4 wt% of PBT weight.

[0034] Example 1.6 Modified PBT substrate, denoted as A6, is prepared as follows: a1. Dissolve A-174 in 90% ethanol aqueous solution to form 2wt% A-174 silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 5-8 minutes. Then add nanofiller composed of nanosilicate and nanocellulose mixed in a 2:1 ratio. Stir at 1000-1500 rpm for 30 minutes to allow silane molecules to be uniformly adsorbed on the surface of the filler. Then dry to remove the solvent and obtain the surface modified nanofiller. a2. Surface-modified nanofiller, PBT, antioxidant 1010 and lubricant EBS are mixed and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm±0.02mm to obtain modified PBT substrate. The amount of nanofiller added is 10.5 wt% of PBT weight, the amount of A-174 added is 1 wt% of nanofiller weight, the amount of antioxidant 1010 is 0.5 wt% of PBT weight, and the amount of lubricant EBS compounded is 0.4 wt% of PBT weight.

[0035] Example 1.7 Modified PBT substrate, denoted as A7, was prepared as follows: a1. Dissolve A-174 in 90% ethanol aqueous solution to form 2wt% A-174 silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 5-8 minutes. Then add nanofiller composed of nanosilicate and nanocellulose mixed in a 1:2 ratio. Stir at 1000-1500 rpm for 30 minutes to make silane molecules uniformly adsorbed on the surface of the filler. Then dry to remove the solvent and obtain surface modified nanofiller. a2. Surface-modified nanofiller, PBT, antioxidant 1010 and lubricant EBS are mixed and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm±0.02mm to obtain modified PBT substrate. The amount of nanofiller added is 10.5 wt% of PBT weight, the amount of A-174 added is 1 wt% of nanofiller weight, the amount of antioxidant 1010 is 0.5 wt% of PBT weight, and the amount of lubricant EBS compounded is 0.4 wt% of PBT weight.

[0036] Comparative Example 1 For the PBT substrate of Example 1.1, denoted as CA1, the specific preparation process is as follows: PBT, antioxidant 1010 and lubricant EBS are mixed, extruded and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm ± 0.02mm to obtain the PBT substrate; the antioxidant 1010 is 0.5wt% of the weight of PBT, and the lubricant EBS is mixed to 0.4wt% of the weight of PBT.

[0037] For the PBT substrate of Example 1.2, denoted as CA2, the specific preparation process is as follows: PBT, nanocellulose, A-174, antioxidant 1010 and lubricant EBS are mixed and extruded and granulated by a twin-screw extruder, and then cast into a film by a casting machine with a film thickness of 0.3mm ± 0.02mm to obtain the PBT substrate; the amount of nanocellulose added is 10.5wt% of the weight of PBT, the amount of A-174 added is 1wt% of the weight of nanocellulose, the amount of antioxidant 1010 is 0.5wt% of the weight of PBT, and the amount of lubricant EBS mixed is 0.4wt% of the weight of PBT.

[0038] The rigidity and toughness of the modified PBT substrates A2~A7 in Example 1 and the PBT substrate CA1 in Comparative Example 1 were tested, and the test results are shown in Table 1.

[0039] Table 1 Properties of modified PBT substrate

[0040] Table 1 shows that the modified PBT substrate of this invention, after surface treatment of the nanofiller with a silane coupling agent and then added to the PBT mixture, has a higher flexural modulus and elongation at break, which greatly improves the rigidity and toughness of the substrate and enhances the support and transparency of the positioning frame paper product. In addition, it was found that the nanofiller composed of nanosilicate and nanocellulose mixed in a ratio of 2:2 to 3 is more helpful in improving the rigidity and toughness of the modified PBT substrate and can further optimize the support of the product.

[0041] Example 2: Siloxane-Polyurethane Hybrid Primer Example 2.1 Siloxane-polyurethane hybrid primer, denoted as B1, is prepared as follows: b1. Mix dihydroxy-terminated polydimethylsiloxane and polyurethane prepolymer containing 5.5% NCO, and add ethyl acetate while stirring at room temperature; b2. Add the catalyst DBTDL (dibutyltin dilaurate), stir for 30 minutes, degas, and obtain the siloxane-polyurethane hybrid primer. The product contains 30wt% dihydroxy-terminated polydimethylsiloxane, 60wt% polyurethane prepolymer containing 5.5% NCO, 4.5wt% ethyl acetate, and 0.5wt% DBTDL catalyst.

[0042] Example 2.2 Siloxane-polyurethane hybrid primer, denoted as B2, is prepared as follows: b1. Mix hydroxypropyl-terminated polydimethylsiloxane and polyurethane prepolymer containing 5.5% NCO, and add ethyl acetate while stirring at room temperature; b2. Add the catalyst DBTDL, stir for 30 minutes, degas, and obtain the siloxane-polyurethane hybrid primer. The product contains 30wt% hydroxypropyl-terminated polydimethylsiloxane, 60wt% polyurethane prepolymer containing 5.5% NCO, 4.5wt% ethyl acetate, and 0.5wt% DBTDL catalyst.

[0043] Comparative Example 2 For the siloxane-polyurethane hybrid primer of Example 2.1, denoted as CB1, the specific preparation process is as follows: b1. Mix polydimethylsiloxane and polyurethane prepolymer containing 5.5% NCO, and add ethyl acetate while stirring at room temperature; b2. Add the catalyst DBTDL, stir for 30 minutes, degas, and obtain the siloxane-polyurethane hybrid primer. The composition includes 30wt% polydimethylsiloxane, 60wt% polyurethane prepolymer containing 5.5% NCO, 4.5wt% ethyl acetate, and 0.5wt% DBTDL catalyst.

[0044] For the siloxane-polyurethane hybrid primer of Example 2.2, denoted as CB2, the specific preparation process is as follows: b1. Mix monohydroxy-terminated polydimethylsiloxane and polyurethane prepolymer containing 5.5% NCO, and add ethyl acetate while stirring at room temperature; b2. Add the catalyst DBTDL, stir for 30 minutes, degas, and obtain the siloxane-polyurethane hybrid primer. The product contains 30wt% monohydroxy-terminated polydimethylsiloxane, 60wt% polyurethane prepolymer containing 5.5% NCO, 4.5wt% ethyl acetate, and 0.5wt% DBTDL catalyst.

[0045] The polyurethane prepolymer containing 5.5% NCO used in Example 2 was generated by reacting isophorone diisocyanate with polyether polyol via the catalyst DBTDL.

[0046] Example 3 Preparation of Nano-Alumina Dispersion Example 3.1 Nano alumina dispersion, denoted as C1, was prepared as follows: c1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. c2. Add calcium lignosulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000-2500 rpm, then ball mill for 30-60 min to obtain nano alumina dispersion. The nano-α-alumina content is 20wt%, the polyurethane resin content is 4wt%, the calcium lignosulfonate content is 0.6%, and the silane coupling agent is 0.8wt% of the nano-α-alumina.

[0047] Example 3.2 Nano alumina dispersion, denoted as C3, was prepared as follows: c1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. c2. Add sodium lignosulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000-2500 rpm, then ball mill for 30-60 min to obtain nano alumina dispersion. The nano-α-alumina content is 25wt%, the polyurethane resin content is 8wt%, the sodium lignosulfonate content is 0.8%, and the silane coupling agent is 1.5wt% of the nano-α-alumina.

[0048] Example 3.3 Nano-alumina dispersion, denoted as C3, was prepared as follows: c1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. c2. Add magnesium lignosulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000-2500 rpm, then ball mill for 30-60 min to obtain nano alumina dispersion. The nano-α-alumina content is 22wt%, the polyurethane resin content is 6wt%, the magnesium lignosulfonate content is 0.1%, and the silane coupling agent is 1wt% of the nano-α-alumina.

[0049] Comparative Example 3 For the nano-alumina dispersion in Example 3.1, denoted as CC1, the specific preparation process is as follows: c1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. c2. Add calcium lignosulfonate and polyacrylate resin and mix. Stir and disperse evenly at 2000-2500 rpm, then ball mill for 30-60 min to obtain nano alumina dispersion. The nano-α-alumina content is 20wt%, the polyacrylate resin content is 4wt%, the calcium lignosulfonate content is 0.6%, and the silane coupling agent is 0.8wt% of the nano-α-alumina.

[0050] The nano-alumina dispersion of Example 3.2, denoted as CC2, was prepared as follows: c1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. c2. Add sodium dodecyl sulfonate and polyurethane acrylate and mix. Stir and disperse evenly at 2000-2500 rpm, then ball mill for 30-60 min to obtain nano alumina dispersion. The nano-α-alumina content is 20wt%, the polyurethane acrylate content is 4wt%, the sodium dodecyl sulfonate content is 0.6%, and the silane coupling agent is 0.8wt% of the nano-α-alumina.

[0051] The preparation process of the nano-alumina dispersion in Example 3.3, denoted as CC3, is as follows: c1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. c2. Add sodium dodecyl sulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000-2500 rpm, then ball mill for 30-60 min to obtain nano alumina dispersion. The nano-α-alumina content is 20wt%, the polyurethane resin content is 8wt%, the sodium dodecyl sulfonate content is 0.6%, and the silane coupling agent is 0.8wt% of the nano-α-alumina.

[0052] The preparation process of the nano-alumina dispersion in Example 3.4, denoted as CC4, is as follows: Nano-alumina, KH-570, sodium dodecyl sulfonate, and polyurethane resin are mixed and dispersed evenly by stirring at 2000-2500 rpm, and then ball-milled for 30-60 min to obtain a nano-alumina dispersion. The nano-α-alumina content is 20wt%, the polyurethane resin content is 8wt%, the sodium dodecyl sulfonate content is 0.6%, and the silane coupling agent is 0.8wt% of the nano-α-alumina.

[0053] For the 3.5 nm alumina dispersion, denoted as CC5, the specific preparation process is as follows: Nano-γ-alumina, KH-570, sodium dodecyl sulfonate, and polyurethane resin are mixed and dispersed evenly by stirring at 2000-2500 rpm, and then ball-milled for 30-60 min to obtain a nano-alumina dispersion. The nano-γ-alumina content is 20wt%, the polyurethane resin content is 8wt%, the sodium dodecyl sulfonate content is 0.6%, and the silane coupling agent content is 0.8wt% of the nano-γ-alumina.

[0054] Wear resistance and adhesion tests were conducted on the nano-alumina dispersions C1~C3 prepared in Example 3 and the nano-alumina dispersions CC1~CC5 prepared in Comparative Example 3.

[0055] Methods: A nano-alumina dispersion was uniformly coated onto a PBT substrate as a base layer and cured to form a 5 μm thick nano-alumina dispersion coating. Abrasion resistance and adhesion were then tested, and the results are shown in Table 2. Abrasion resistance was assessed using the steel wool abrasion test (number of rubs), and adhesion was assessed using the cross-cut test (0-5 levels, with higher levels being better, and 4-5 being excellent).

[0056] Table 2 Performance of Nano-Alumina Dispersion

[0057] Table 2 shows that the nano-alumina dispersion of the present invention uses nano-α-alumina, and after surface treatment of nano-α-alumina with silane coupling agent, polyurethane resin is used as a polymeric dispersant and anionic lignin sulfonate is used as a polymeric dispersant, so that the nano-alumina dispersion coating has higher adhesion and wear resistance.

[0058] Examples 4-10 and Comparative Examples 4-6 A manufacturing process for a transparent composite positioning frame includes the following steps: (1) Using the modified PBT substrate of Example 1 as the base layer, the siloxane-polyurethane hybrid primer prepared in Example 2 and Comparative Example 2 is uniformly coated on the modified PBT substrate and cured to form a siloxane-polyurethane hybrid primer layer with a thickness of 5 μm. (2) The nano-alumina dispersion prepared in Example 3 was uniformly coated on the siloxane-polyurethane hybrid primer layer and cured to form a nano-alumina dispersion coating with a thickness of 5 μm. (3) Print the UV ink onto the nano-alumina dispersion I coating and cure it with UV to form an ink layer with a thickness of 8μm; (4) Place the hot stamping foil on the ink layer and heat and pressurize it: temperature 105~135℃, pressure 0.2~0.5MPa, time 1~2s, so that the metal layer of the hot stamping foil is transferred to the ink surface to form a hot stamping layer. Then, heat it to 85~95℃ at 1~2℃ / min, keep it at 50~70min, and then cool it down at 1~2℃ / min.

[0059] The modified PBT substrate, siloxane-polyurethane hybrid primer, nano-alumina dispersion, and UV ink were prepared according to the combinations selected in Table 3 in Examples 4-10 and Comparative Examples 4-6.

[0060] The UV inks in Examples 4-10 and Comparative Examples 4 and 5 are inks made of a mixture of epoxy acrylate and polyurethane acrylate, with an epoxy acrylate content of 25-30 wt% and a polyurethane acrylate content of 30-35 wt%; the UV ink in Comparative Example 6 is an ink made of epoxy acrylate, with an epoxy acrylate content of 60%.

[0061] Table 3. Coating composition of transparent PBT positioning frame paper

[0062] Comparative Example 7 The production process of a transparent composite positioning frame differs from that of Example 7 in that: (4) after the hot stamping layer is formed, no heat treatment is performed.

[0063] Comparative Example 8 The production process of a transparent composite positioning frame differs from that of Example 7 in that: (4) after forming the hot stamping layer, heat treatment is performed: the frame is placed directly at 85~95℃ and kept at that temperature for 50~70 minutes.

[0064] The rigidity, toughness, abrasion resistance and adhesion of the transparent PBT positioning frame paper in Examples 4-10 and Comparative Examples 4-8 were tested, and the warping phenomenon was observed. The test results are shown in Table 4.

[0065] Table 4 Properties of Transparent PBT Positioning Frame Paper

[0066] Table 4 illustrates that the transparent PBT positioning frame paper of this invention uses a modified PBT substrate with a silane coupling agent surface-treated with nanofillers as the bottom layer, a siloxane-polyurethane hybrid primer layer prepared with hydroxyl-terminated polysiloxane and a polyurethane prepolymer containing 5.5% NCO, and a nano-alumina dispersion coating prepared by surface-treating nano-α-alumina with a silane coupling agent combined with polyurethane resin and anionic lignin sulfonate to form a double-layer base coat. This is then combined with a UV ink made from a mixture of epoxy acrylate and polyurethane acrylate. This not only gives the transparent PBT positioning frame paper excellent transparency but also significantly improves its flexural modulus, elongation at break, scratch resistance, and adhesion grade. The support strength of the transparent PBT positioning frame paper is effectively enhanced, resulting in good rigidity and abrasion resistance during printing. It also promotes ink adhesion and avoids warping of the transparent PBT positioning frame paper, solving the problems of insufficient rigidity, poor abrasion resistance, or low ink adhesion in ordinary printing.

[0067] Comparing Examples 4 and 5 with Example 7, it was found that using polysiloxanes with hydroxyl end caps not only helps to improve the adhesion between the coating and the substrate, but also further enhances the rigidity and toughness of the transparent PBT positioning frame paper, improving its abrasion resistance.

[0068] Comparing Example 6 with Example 7, it was found that the UV ink containing polyurethane acrylate is more beneficial in improving the scratch resistance of the ink on transparent PBT positioning frame paper.

[0069] By comparing Examples 7 and 8 with Example 7, it was found that the use of heated heat treatment is beneficial to reduce the warping of the transparent PBT positioning frame paper.

[0070] Example 11 Preparation of waterborne polyurethane wear-resistant fluid Example 11.1 Waterborne polyurethane wear-resistant fluid, denoted as D1, is prepared as follows: d1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and nano-zinc oxide with a particle size of 20-30 nm. Stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. d2. Add calcium lignosulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000~2500 rpm, then ball mill for 30~60 min to obtain water-based polyurethane wear-resistant liquid. The nano-α-alumina content is 2wt%, the nano-zinc oxide content is 5%, the polyurethane resin content is 10wt%, the calcium lignosulfonate content is 0.5%, and the silane coupling agent is 0.8wt% of the sum of nano-α-alumina and nano-zinc oxide.

[0071] Example 11.2 Waterborne polyurethane wear-resistant fluid, denoted as D2, is prepared as follows: d1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and nano-zinc oxide with a particle size of 20-30 nm. Stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. d2. Add sodium lignosulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000-2500 rpm, then ball mill for 30-60 minutes to obtain water-based polyurethane wear-resistant liquid. The nano-α-alumina content is 6wt%, the nano-zinc oxide content is 10%, the polyurethane resin content is 12wt%, the calcium lignosulfonate content is 0.8%, and the silane coupling agent is 1.2wt% of the sum of nano-α-alumina and nano-zinc oxide.

[0072] Example 11.3 Waterborne polyurethane wear-resistant fluid, denoted as D3, is prepared as follows: d1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and nano-zinc oxide with a particle size of 20-30 nm. Stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. d2. Add magnesium lignosulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000~2500 rpm, then ball mill for 30~60 min to obtain water-based polyurethane wear-resistant liquid. The nano-α-alumina content is 4wt%, the nano-zinc oxide content is 8%, the polyurethane resin content is 15wt%, the calcium lignosulfonate content is 1%, and the silane coupling agent is 1.5wt% of the sum of nano-α-alumina and nano-zinc oxide.

[0073] Comparative Example 9 For the aqueous polyurethane wear-resistant fluid of Example 9.1, denoted as CD1, the specific preparation process is as follows: d1. Dissolve KH-570 in 50% ethanol aqueous solution to form silane solution. Adjust the pH to 4-5 with 0.1% acetic acid and hydrolyze for 10-15 min. Then add nano-α-alumina with a particle size of 30-50 nm and stir at 1000-1500 rpm for 30 min to make silane molecules uniformly adsorbed on the surface of the filler. d2. Add magnesium lignosulfonate and polyurethane resin and mix. Stir and disperse evenly at 2000~2500 rpm, then ball mill for 30~60 min to obtain water-based polyurethane wear-resistant liquid. The nano-α-alumina content is 12wt%, the polyurethane resin content is 15wt%, the calcium lignosulfonate content is 1%, and the silane coupling agent is 1.5wt% of the nano-α-alumina.

[0074] Examples 12-14 and Comparative Example 10 A manufacturing process for a transparent composite positioning frame includes the following steps: (1) Using the modified PBT substrate of Example 1 as the base layer, the siloxane-polyurethane hybrid primer prepared in Example 2 was uniformly coated on the modified PBT substrate and cured to form a siloxane-polyurethane hybrid primer layer with a thickness of 5 μm. (2) The nano-alumina dispersion prepared in Example 3 was uniformly coated on the siloxane-polyurethane hybrid primer layer and cured to form a nano-alumina dispersion coating with a thickness of 5 μm. (3) Print the UV ink onto the nano-alumina dispersion I coating and cure it with UV to form an ink layer with a thickness of 8μm; The UV ink is a mixture of epoxy acrylate and polyurethane acrylate, with the acrylate content being 30wt% and the polyurethane acrylate content being 30wt%.

[0075] (4) Place the hot stamping foil on the ink layer and heat and pressurize it: temperature 105~135℃, pressure 0.2~0.5MPa, time 1~2s, so that the metal layer of the hot stamping foil is transferred to the ink surface to form a hot stamping layer; 5) Spray the water-based polyurethane wear-resistant liquid prepared in Example 11 and Comparative Example 9 onto the ink layer, cure it to form a water-based polyurethane wear-resistant coating with a thickness of 0.5 μm, and finally heat treat it by raising the temperature to 85-95°C at 1-2°C / min and holding it at 50-70 min, and then cooling it down at 1-2°C / min.

[0076] The modified PBT substrate, siloxane-polyurethane hybrid primer, nano-alumina dispersion, and waterborne polyurethane wear-resistant liquid were prepared according to Examples 12-14 and Comparative Example 10 based on the combination of the modified PBT substrate, siloxane-polyurethane hybrid primer, nano-alumina dispersion, and waterborne polyurethane wear-resistant liquid in Table 5.

[0077] Table 5 Transparent PBT positioning frame paper (with a thin layer of water-based polyurethane abrasion-resistant coating sprayed onto the ink layer)

[0078] The rigidity, toughness, abrasion resistance, and ultraviolet (320-400nm) transmittance of the transparent PBT positioning frame paper in Examples 4 and 12-14 and Comparative Example 11 were tested, and the test results are shown in Table 6.

[0079] Table 6. Performance of Transparent PBT Positioning Frame Paper (with a thin layer of water-based polyurethane abrasion-resistant coating sprayed onto the ink layer).

[0080] Table 4 illustrates that the transparent PBT positioning frame paper of this invention uses a modified PBT substrate with a silane coupling agent surface-treated with nanofillers as the base layer. A siloxane-polyurethane hybrid primer layer is prepared using hydroxyl-terminated polysiloxane and a polyurethane prepolymer containing 5.5% NCO. A nano-alumina dispersion coating layer is prepared by surface-treating nano-α-alumina with a silane coupling agent and combining it with polyurethane resin and anionic lignin sulfonate, forming a double-layer base coat. This is then combined with a UV ink made from a mixture of epoxy acrylate and polyurethane acrylate, and finally sprayed with a thin layer of water-based polyurethane abrasion-resistant coating. The water-based polyurethane abrasion-resistant coating uses a combination of nano-α-alumina and nano-zinc oxide, which not only improves the product's rigidity, toughness, and abrasion resistance, but also enhances the adhesion of the hot stamping layer, reducing the risk of hot stamping layer peeling off. Simultaneously, it significantly reduces ultraviolet (320~400nm) transmittance, improves ultraviolet shielding, and greatly extends the service life.

[0081] In summary, the production process of the transparent PBT positioning frame paper of the present invention can improve the supporting strength of the frame paper and solve the problems of insufficient rigidity, poor abrasion resistance or low ink adhesion in ordinary printing.

[0082] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit and essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0083] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A manufacturing process for a transparent composite positioning frame, characterized in that, Includes the following steps: (1) Using modified PBT substrate as base layer, first uniformly apply siloxane-polyurethane hybrid primer on modified PBT substrate and cure to form siloxane-polyurethane hybrid primer layer. (2) The nano-alumina dispersion is uniformly coated on the siloxane-polyurethane hybrid primer layer and cured to form a nano-alumina dispersion coating. (3) Print UV ink onto the nano-alumina dispersion I coating, and cure with UV to form an ink layer; (4) Place the hot stamping foil on the ink layer, heat and pressurize it to transfer the metal layer of the hot stamping foil to the ink surface to form a hot stamping layer, and then heat treat it. The modified PBT substrate is prepared from PBT, nanofillers, silane coupling agents and auxiliary raw materials, wherein the silane coupling agent modifies the surface of the nanofillers. The siloxane-polyurethane hybrid primer is prepared from hydroxyl-terminated polysiloxane, a polyurethane prepolymer containing 5.5% NCO, ethyl acetate, and the catalyst DBTDL. The nano-alumina dispersion is prepared from nano-α-alumina, silane coupling agent, anionic lignin sulfonate, polyurethane resin and ethanol aqueous solution, wherein the silane coupling agent modifies the surface of the nano-α-alumina.

2. The manufacturing process of a transparent composite positioning frame according to claim 1, characterized in that, It also includes step (5): spray the prepared water-based polyurethane wear-resistant liquid onto the ink layer, cure it to form a water-based polyurethane wear-resistant coating, and finally heat treat it. When performing step (5), the hot stamping layer formed in step 4 is not heat treated. The waterborne polyurethane wear-resistant fluid is prepared from nano-α-alumina, nano-zinc oxide, silane coupling agent, anionic lignin sulfonate, polyurethane resin and ethanol aqueous solution. The silane coupling agent modifies the surface of nano-α-alumina and nano-zinc oxide.

3. The manufacturing process of a transparent composite positioning frame according to claim 1, characterized in that, In the modified PBT substrate, the amount of nanofiller added is 9-12 wt% of the weight of PBT, the amount of silane coupling agent added is 0.8-1.5 wt% of the weight of nanofiller, and the amount of additives is 0.5-1 wt% of the weight of PBT.

4. The manufacturing process of a transparent composite positioning frame according to claim 1 or 3, characterized in that, The nanofiller is composed of nanosilicate and nanocellulose mixed in a ratio of 2:2 to 3; the silane coupling agent is one or both of A-174 and KH-570.

5. The manufacturing process of a transparent composite positioning frame according to claim 1, characterized in that, In the siloxane-polyurethane hybrid primer, the content of polysiloxane with hydroxyl end caps is 30wt%, the content of ethyl acetate is 4.5~7wt%, the content of catalyst DBTDL is 0.5wt%, and the remainder is a polyurethane prepolymer containing 5.5% NCO.

6. The manufacturing process of a transparent composite positioning frame according to claim 1 or 5, characterized in that, In siloxane-polyurethane hybrid primers, the polysiloxanes with hydroxyl end caps are selected from either dihydroxyl-terminated polydimethylsiloxane or hydroxypropyl-terminated polydimethylsiloxane.

7. The manufacturing process of a transparent composite positioning frame according to claim 1 or 2, characterized in that, The anionic lignin sulfonate is calcium lignin sulfonate, sodium lignin sulfonate, or magnesium lignin sulfonate. In step (4) or (5), the heat treatment conditions are as follows: heat up to 85-95℃ at 1-2℃ / min, hold for 50-70min, and then cool down at 1-2℃ / min.

8. The manufacturing process of a transparent composite positioning frame according to claim 1, characterized in that, In the nano-alumina dispersion, the content of nano-α-alumina is 20~25wt%, the content of polyurethane resin is 4~8wt%, the content of anionic lignin sulfonate is 0.5~1%, and the content of silane coupling agent is 0.8~1.5wt% of nano-α-alumina.

9. The manufacturing process of a transparent composite positioning frame according to claim 1, characterized in that, The UV ink is a mixture of acrylate system and polyurethane acrylate; in the UV ink, the content of acrylate system is 25~30wt%, and the content of polyurethane acrylate is 30~35wt%.

10. The manufacturing process of a transparent composite positioning frame according to claim 2, characterized in that, In the waterborne polyurethane wear-resistant fluid, the content of nano-α-alumina is 2~6wt%, nano-zinc oxide is 5~10%, polyurethane resin is 10~15wt%, anionic lignin sulfonate is 0.5~1%, and silane coupling agent is 0.8~1.5wt% of the sum of nano-α-alumina and nano-zinc oxide.

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