A dry-wet composite process for vacuum aluminum-coated paper

Abstract

The application relates to the field of vacuum aluminum-plated paper processing and specifically discloses a dry-wet compounding process for vacuum aluminum-plated paper. The dry-wet compounding process for vacuum aluminum-plated paper comprises the following preparation steps: S1, coating a bottom adhesive on a film, and heat setting one side of the bottom adhesive close to the film; S2, compounding the heat-set bottom adhesive with base paper, curing the bottom adhesive, and forming a bottom coating layer on the surface of the base paper; S3, vacuum aluminum plating on the side of the bottom coating layer away from the base paper to form a vacuum aluminum-plated layer; and S4, coating a surface adhesive on the side of the vacuum aluminum-plated layer away from the bottom coating layer, curing to form a surface coating layer, and obtaining vacuum aluminum-plated composite paper. The dry-wet compounding process can improve the amount of the bottom adhesive without causing overflow of the bottom adhesive, improve the folding resistance of the obtained vacuum aluminum-plated paper, and solve the color explosion problem.

Description

Technical Field

[0001] This application relates to the field of vacuum metallized paper processing, and more specifically, it relates to a dry-wet lamination process for vacuum metallized paper. Background Technology

[0002] Vacuum metallized paper is generally composed of base paper, base coating, vacuum metallized layer and top coating. It has good gloss and smoothness, good flexibility, high metallization layer fastness, and is beautiful and environmentally friendly. It also has good printing and machining performance. Therefore, it can be widely used for exquisite packaging of products such as cigarettes, wine, bottle labels, tea, food, cosmetics, daily chemicals, department stores, gifts, and handicrafts. It can also be used in building decoration materials.

[0003] Vacuum metallized paper lamination processes generally include wet lamination and dry lamination. The wet lamination process involves laminating a film coated with a primer onto the base paper. After drying, the film is peeled off, allowing the primer to adhere to the base paper while it is still uncured. The primer and base paper have good adhesion, but the amount of primer used is typically around 4 g / m². 2 The vacuum-metallized paper produced is prone to problems such as poor folding resistance and color bleeding. If the amount of base coating adhesive is too large, adhesive overflow may occur. The dry lamination process involves directly drying the film coated with base coating adhesive and then laminating it with the base paper. Although this can increase the amount of base coating adhesive used, the amount of base coating adhesive used is generally 20-30 g / m². 2 It does not cause glue overflow, but the adhesion stability between the dry base coating and the base paper is low, and the base paper generally needs to be un-flattened, so the choice of base paper is limited. The stability and folding endurance of the vacuum metallized paper are also low, and it is easy to cause color bursting problems during use. Summary of the Invention

[0004] To address the issue that conventional vacuum metallized paper lamination processes cannot simultaneously achieve good bonding stability and adhesive overflow, resulting in vacuum metallized paper that is prone to folding problems and color bleeding, this application provides a dry-wet lamination process for vacuum metallized paper.

[0005] This application provides a dry-wet lamination process for vacuum metallized paper, employing the following technical solution:

[0006] A dry-wet lamination process for vacuum metallized paper includes the following preparation steps:

[0007] S1. Apply a primer to the film and heat-set the side of the primer closest to the film.

[0008] S2. The heat-set base coating is laminated with the base paper, and the base coating is cured to form a base coating layer on the surface of the base paper; S3. Vacuum aluminum plating is performed on the side of the base coating layer away from the base paper to form a vacuum aluminum plating layer.

[0009] S4. Apply adhesive to the side of the vacuum aluminized layer away from the base coating layer, and cure to form a top coating layer, thus obtaining vacuum aluminized composite paper.

[0010] By adopting the above technical solution, the primer is first uniformly coated onto the film, and then heat-set, so that the primer on the film is partially cured. After heat setting, the primer is not easy to overflow or deform, and it also maintains good adhesion. This allows the partially cured primer to be stably bonded to the original paper on the side away from the film. The primer is then further cured to form a smooth and stably bonded primer layer on the surface of the original paper. After peeling off the film, vacuum aluminum plating is performed on the side of the primer layer away from the original paper to form a vacuum aluminum plating layer. The vacuum aluminum plating layer can give the vacuum aluminum paper a metallic texture and luster. Finally, a topcoat is applied to the surface of the vacuum aluminum plating layer to form a topcoat layer. The topcoat layer provides good protection for the vacuum aluminum plating layer and improves its wear resistance and scratch resistance.

[0011] The dry-wet lamination process of this application increases the amount of base coating adhesive used by first heat-setting the base coating adhesive, then laminating and transferring it, and finally curing it. The base coating adhesive does not overflow or become uneven. Vacuum aluminizing is then performed on the surface of a thick base paper. The base coating layer provides a good buffer for the vacuum aluminized layer, improving the folding endurance of the resulting vacuum aluminized paper and mitigating the color splatter problem. The base paper used in this application can be either leveled or unleveled, with limited requirements on the selection range, making it suitable for continuous industrial production.

[0012] Preferably, in step S1, the amount of the primer coating is 40-50 g / m². 2 The heat setting temperature is 90-110℃, and the heat setting time is 10-20s.

[0013] By adopting the above technical solution, the vacuum metallized paper prepared with a base coating of optimal thickness has good flatness and folding resistance, and is not prone to color bursting. When the thickness of the base coating is too thin, the vacuum metallized paper prepared is not foldable and is prone to color bursting. The optimal heat setting temperature and time allow the base coating to partially cure on the film surface, so that the base coating can maintain good adhesion stability without being easily deformed or overflowing. This improves the flatness and stability of the bonding between the base coating and the base paper, thereby improving the folding resistance of the prepared vacuum metallized paper and improving the color bursting problem.

[0014] Preferably, the composite pressure in step S2 is 0.1-0.3 kPa, the curing time is 5-10 min, and the curing temperature is 80-100℃.

[0015] By adopting the above technical solutions, the optimal composite pressure enables the base coating adhesive to be stably bonded to the surface of the base paper and gives the base coating adhesive good flatness; the optimal curing temperature and curing time enable the base coating adhesive to be stably cured, reducing the occurrence of bubbles and shrinkage in the base coating adhesive, thereby improving the bonding stability and flatness of the base coating adhesive on the surface of the base paper.

[0016] Preferably, the smoothness of the base paper is 400-600s.

[0017] By adopting the above technical solution, this application selects base paper with high flatness. The bottom coating adhesive can have good bonding stability on base paper with good flatness, reducing the occurrence of adhesive overflow. This shows that the composite process of this application can also be applied to base paper with low flatness, thus increasing the range of base paper options.

[0018] Preferably, the primer is made from the following percentages of raw materials:

[0019] 30-50% waterborne polyurethane prepolymer emulsion

[0020] Adhesion promoter 5-10%

[0021] Wetting and dispersing agent 1-3%

[0022] Curing agent 2-4%

[0023] Water balance.

[0024] By adopting the above technical solution, the waterborne polyurethane prepolymer emulsion has good flexibility and film-forming properties, and produces a good synergistic effect with the adhesion promoter. It can be uniformly cast on the film surface and heat-set to form a non-deformable base coating. Under the action of the curing agent, it is cured to form a smooth and uniform base coating. The wetting and dispersing agent can further improve the wetting and dispersing properties of the base coating on the film surface, thereby improving the adhesion and smoothness of the base coating on the base paper surface. The base coating prepared in this way has good uniformity and is not prone to overflow. After heat setting, it can still maintain good adhesion stability. The cured base coating has good flexibility and smoothness. The vacuum metallized paper has good bending resistance and is not prone to color bursting.

[0025] Preferably, the aqueous polyurethane prepolymer emulsion is prepared by the following steps:

[0026] A1. Add 40-60 parts of diisocyanate, 5-15 parts of polycaprolactone polyol, 3-8 parts of allyl glycidyl ether, 4-6 parts of 3-diethylenetriaminepropylmethyldimethoxysilane and 0.5-1.5 parts of catalyst to the reaction equipment, and react under vacuum to obtain polyurethane prepolymer.

[0027] A2. Add 3-6 parts of hydrophilic chain extender to the polyurethane prepolymer obtained in step A1, and react under vacuum to obtain polyurethane chain extender prepolymer.

[0028] A3. Add 2-5 parts of neutralizer, 3-5 parts of emulsifier and 20-30 parts of water to the polyurethane chain extender prepolymer obtained in step A2, and continue the reaction to obtain an aqueous polyurethane prepolymer emulsion.

[0029] By adopting the above technical solution, firstly, under the action of a catalyst, diisocyanate reacts with polycaprolactone polyol, allyl glycidyl ether, and 3-diethylenetriaminepropylmethyldimethoxysilane to introduce long-chain ether segments and branched amino segments into the polyurethane chain. Allyl glycidyl ether and 3-diethylenetriaminepropylmethyldimethoxysilane produce a good synergistic effect, forming a network cross-linked macromolecular structure, which improves the adhesion, flexibility, and dispersion uniformity of the prepared primer. The reaction produces an isocyanate-terminated polyurethane prepolymer. Then, a hydrophilic chain extender is added to the polyurethane prepolymer to obtain a polyurethane chain extender prepolymer with good hydrophilicity. Finally, water, emulsifier, and neutralizer are added to the polyurethane chain extender prepolymer. Under the action of the emulsifier and neutralizer, the polyurethane chain extender prepolymer is emulsified and dispersed, thereby obtaining a stable waterborne polyurethane prepolymer emulsion.

[0030] The aqueous polyurethane prepolymer emulsion prepared in this application has a good network macromolecular structure, which can improve the adhesion and flexibility of the primer, so that the primer can be uniformly cast and dispersed on the surface of the film without overflowing, and has good adhesion stability to the base paper.

[0031] Preferably, the reaction temperature in step S1 is 75-85℃ and the reaction time is 1-2h.

[0032] By adopting the above technical solution, the optimized reaction temperature and reaction time enable diisocyanate, polycaprolactone polyol, allyl glycidyl ether and 3-diethylenetriaminepropylmethyldimethoxysilane to react stably under the catalysis of the catalyst, thereby improving the reaction stability of the obtained polyurethane prepolymer.

[0033] Preferably, the adhesion promoter is composed of pentaerythritol triallyl ether and diaminosilane oligomer in a weight ratio of 1:(0.5-1).

[0034] By adopting the above technical solution, pentaerythritol triallyl ether and diaminosilane oligomers can be further cross-linked and polymerized with waterborne polyurethane prepolymer emulsion, further improving the bonding stability of the prepared base coating on flat base paper. At the same time, the macromolecular network structure formed by cross-linking can further improve the flexibility of the base coating, thereby improving the folding endurance of the prepared vacuum metallized paper and reducing the problem of color bursting.

[0035] Preferably, the wetting and dispersing agent is any one or a combination of sodium polyacrylate, sodium polycarboxylate, and ammonium polycarboxylate.

[0036] By adopting the above technical solution, the wetting and dispersing agent can improve the wetting and dispersibility of the base coating on the flat surface of the base paper, so that the base coating adheres to the surface of the base paper evenly and stably, improve the adhesion stability and flatness of the base coating, and thus improve the stability and folding resistance of the vacuum metallized paper.

[0037] Preferably, the curing agent is an isocyanate-based curing agent.

[0038] By adopting the above technical solution, isocyanate curing agents can improve the curing rate of the primer, enabling the primer to cure evenly and stably, and improving the bonding stability between the primer and the base paper.

[0039] In summary, this application has the following beneficial effects:

[0040] 1. The dry-wet lamination process of this application, by first heat-setting the base coating adhesive, then laminating and transferring it and curing it, increases the amount of base coating adhesive used, and the base coating adhesive will not produce overflow or unevenness. Vacuum metallization is performed on the surface of a thick base paper. The base coating layer can play a good buffering role for the vacuum metallized layer, improving the folding endurance of the obtained vacuum metallized paper and improving the color bursting problem. The base paper of this application can be either leveled or unleveled, with low requirements on the selection range of base paper, and is suitable for continuous industrial production.

[0041] 2. A polyurethane prepolymer is prepared by reacting diisocyanate, polycaprolactone polyol, allyl glycidyl ether, and 3-diethylenetriaminepropylmethyldimethoxysilane under the action of a catalyst. This prepolymer is then further reacted with a hydrophilic chain extender to obtain a polyurethane chain extender prepolymer. A neutralizer, emulsifier, and water are then added to prepare an aqueous polyurethane prepolymer emulsion. This emulsion is further compounded with an adhesion promoter, wetting and dispersing agent, curing agent, and water to prepare a primer. The resulting primer exhibits good adhesion and flexibility, improving the adhesion stability to the base paper, enhancing the folding resistance of vacuum metallized paper, and reducing the risk of bursting.

[0042] 3. By using an adhesion promoter composed of pentaerythritol triallyl ether and diaminosilane oligomers, it is possible to further crosslink and polymerize with the waterborne polyurethane prepolymer emulsion, thereby further improving the bonding stability of the prepared primer on the flat base paper. At the same time, the macromolecular network structure formed by crosslinking can further improve the flexibility of the primer, thereby improving the folding endurance of the prepared vacuum metallized paper and reducing the occurrence of color bursting problems. Detailed Implementation

[0043] The present application will be further described in detail below with reference to the embodiments.

[0044] The following are some of the sources and specifications of the raw materials used in this application. The raw materials used in the preparation examples and embodiments of this application can all be obtained commercially, including but not limited to the following models and manufacturers of raw materials. Raw materials with equivalent performance can also be used:

[0045] 1. Films: BOPET release film: thickness 25-50μm, peel force 5-15g / in; BOPP release film: thickness 25-50μm, peel force 5-15g / in;

[0046] 2. Base paper: All wood pulp base paper, moisture content 4-5%;

[0047] 3. 3-Diethylenetriaminepropylmethyldimethoxysilane: Nanjing Nengdexin SCA-A30T;

[0048] 4. Allyl glycidyl ether: Tosoh Chemical, CAS No. 106-92-3, density 0.981 g / cm³ 3 ;

[0049] 5. Pentaerythritol triallyl ether: density 0.985 g / cm³ 3 CAS No. 1471-17-6;

[0050] 6. Diaminosilane oligomers: Aikepu 5246;

[0051] 7. Isocyanate curing agents: Covestro Z4470MPA / X;

[0052] 8. Polycaprolactone polyols: Polycaprolactone diol: molecular weight 2000, hydroxyl value 54-58 KOH mg / g, viscosity 400 mPa·s / 60℃; Polycaprolactone triol: molecular weight 2000, hydroxyl value 80-88 KOH mg / g, viscosity 300 mPa·s / 60℃.

[0053] Preparation example of waterborne polyurethane prepolymer emulsion

[0054] Preparation Example 1

[0055] Preparation Example 1 discloses an aqueous polyurethane prepolymer emulsion, which is prepared by the following steps:

[0056] A1. 4 kg of isophorone diisocyanate as diisocyanate, 0.5 kg of polycaprolactone diol as polycaprolactone polyol, 0.8 kg of allyl glycidyl ether, 0.4 kg of 3-diethylenetriaminepropylmethyldimethoxysilane and 0.05 kg of dibutyltin dilaurate as catalyst were added to a reaction vessel. The vacuum degree was maintained at -0.08 MPa and the reaction was carried out at 75℃ for 1 h to obtain a polyurethane prepolymer.

[0057] A2. Add 0.45 kg of dimethylolpropionic acid as a hydrophilic chain extender to the polyurethane prepolymer obtained in step A1, maintain a vacuum of -0.08 MPa, and react at 80°C for 30 min to obtain the polyurethane chain extender prepolymer.

[0058] A3. Add 0.2 kg of triethanolamine as a neutralizing agent, 0.3 kg of sodium ethylenediamine ethanesulfonate as an emulsifier, and 2 kg of water to the polyurethane chain extender prepolymer obtained in step A2. React at 70°C for 40 min to obtain an aqueous polyurethane prepolymer emulsion.

[0059] Preparation Examples 2-3

[0060] The difference between Preparation Example 2-3 and Preparation Example 1 lies in the amount of raw materials used and the preparation conditions, as detailed in Table 1 below.

[0061] Table 1. Raw material amounts and preparation conditions for preparation examples 1-3

[0062]

[0063]

[0064] Preparation Example 4

[0065] The difference between Preparation Example 4 and Preparation Example 1 is that allyl glycidyl ether is replaced in equal amounts with polytetramethyl ether diol, which has a molecular weight of 2000 and a hydroxyl value of 54.7-57.5 KOH mg / g. Otherwise, they are the same as Preparation Example 1.

[0066] Preparation Example 5

[0067] The difference between Preparation Example 5 and Preparation Example 1 is that 3-diethylenetriaminepropylmethyldimethoxysilane is replaced with γ-aminopropylmethyldiethoxysilane in equal amounts, while the rest is the same as Preparation Example 1.

[0068] Preparation Example 6

[0069] The difference between Preparation Example 6 and Preparation Example 1 is that 3-diethylenetriaminepropylmethyldimethoxysilane is replaced with an equal amount of allyl glycidyl ether, otherwise the same as Preparation Example 1.

[0070] Preparation Example 7

[0071] The difference between Preparation Example 7 and Preparation Example 1 is that polycaprolactone polyol is replaced by an equal amount of polycarbonate diol. The polycarbonate diol has a molecular weight of 2000, a hydroxyl content of 1.7%, and a viscosity of 1550 cps. The rest is the same as Preparation Example 1.

[0072] Example

[0073] Example 1

[0074] Example 1 discloses a dry-wet lamination process for vacuum metallized paper, including the following steps:

[0075] S1. Using BOPET release film as the thin film, with a density of 40 g / m 2 The amount of commercially available primer is applied, and the side of the primer closest to the film is heat-set at a temperature of 90°C for 10 seconds.

[0076] S2. Apply the heat-set primer to a surface with a smoothness of 400s and a weight of 80g / m². 2 The base paper is rolled and laminated, and the rolling pressure is controlled at 0.1 kPa. Then, the base coating is cured at 80°C for 5 minutes to form a base coating on the surface of the base paper.

[0077] S3. Using a vacuum metallization device, perform vacuum metallization on the side of the base coating away from the original paper, and control the thickness of the vacuum metallization to 20nm to form a vacuum metallization layer on the base coating.

[0078] S4. Apply 3g / m to the side of the vacuum-plated aluminum layer away from the base coating. 2 The coating amount is applied to the surface of the adhesive, which is then cured at a temperature of 80℃ for 30 seconds to form a surface coating, thus obtaining vacuum metallized composite paper.

[0079] Both the commercially available primer and topcoat are water-based polyurethane resins, manufactured by Wenzhou Guoshibang Polymer Materials Co., Ltd., with a solid content of 40%, a viscosity of 400 cps, and a pH of 7-9.

[0080] Example 2-3

[0081] The difference between Examples 2-3 and Example 1 lies in the different preparation conditions and process parameters, as detailed in Table 2 below.

[0082] Table 2. Preparation conditions and process parameters for Examples 1-3

[0083]

[0084] Example 4

[0085] The difference between Example 4 and Example 1 is that the source of the primer is different. The primer in Example 4 is prepared by the following steps: 4 kg of waterborne polyurethane prepolymer emulsion prepared in Example 1 and 0.2 kg of dispersant 5040 are added to 4.85 kg of water as wetting and dispersing agents. After being dispersed evenly, 0.75 kg of adhesion promoter (composed of polyethylene glycol diglycidyl ether and vinyltrimethoxysilane in a weight ratio of 1:1) and 0.2 kg of isocyanate curing agent are added and stirred evenly to obtain the primer; the dispersant 5040 is Nopco SN-5040.

[0086] Examples 5-6

[0087] The difference between Examples 5-6 and Example 4 lies in the amount of raw materials used, the preparation conditions, and the source of the primer. See Table 3 below for details.

[0088] Table 3. Raw material usage and preparation conditions for Examples 4-6

[0089]

[0090] Examples 7-10

[0091] The difference between Examples 7-10 and Example 4 is that the source of the waterborne polyurethane prepolymer resin in the primer is different, as detailed in Table 4 below.

[0092] Table 4. Source of the primer adhesive in Examples 7-10

[0093]

[0094]

[0095] Example 11

[0096] The difference between Example 11 and Example 4 is that the adhesion promoter is different. The adhesion promoter in Example 11 is composed of an aqueous styrene-acrylic emulsion and a diaminosilane oligomer. The amount of aqueous styrene-acrylic emulsion is 0.5 kg and the amount of diaminosilane oligomer is 0.25 kg. Everything else is the same as in Example 4.

[0097] Example 12

[0098] The difference between Example 12 and Example 4 is that the adhesion promoter in Example 12 is composed of pentaerythritol triallyl ether and diaminosilane oligomer. The amount of pentaerythritol triallyl ether is 0.5 kg and the amount of diaminosilane oligomer is 0.25 kg. The rest is the same as in Example 4.

[0099] Example 13

[0100] The difference between Example 13 and Example 4 is that the adhesion promoter in Example 13 is composed of pentaerythritol triallyl ether and diaminosilane oligomer. The amount of pentaerythritol triallyl ether is 0.375 kg and the amount of diaminosilane oligomer is 0.375 kg. The rest is the same as in Example 4.

[0101] Comparative Example

[0102] Comparative Example 1

[0103] The difference between Comparative Example 1 and Example 1 lies in the different preparation steps:

[0104] S1. Using BOPET release film as the thin film, with a density of 40 g / m 2 The amount of coating applied to commercially available primer;

[0105] S2. Roll-press the base coating with the base paper with a smoothness of 400s, control the rolling pressure of the composite to be 0.1KPa, and then cure the base coating at a temperature of 80℃ for 5 minutes to form a base coating on the surface of the base paper.

[0106] S3. Using a vacuum metallization device, perform vacuum metallization on the side of the base coating away from the original paper, and control the thickness of the vacuum metallization to 20nm to form a vacuum metallization layer on the base coating.

[0107] S4. Apply 3g / m to the side of the vacuum-plated aluminum layer away from the base coating. 2 The coating amount is applied to the surface of the adhesive, which is then cured at a temperature of 80℃ for 30 seconds to form a surface coating, thus obtaining vacuum metallized composite paper.

[0108] Both the commercially available primer and topcoat are water-based polyurethane resins, manufactured by Wenzhou Guoshibang Polymer Materials Co., Ltd., with a solid content of 40%, a viscosity of 400 cps, and a pH of 7-9.

[0109] Performance testing

[0110] The following tests were conducted on the performance of the vacuum metallized paper prepared in Examples 1-13 and Comparative Example 1:

[0111] 1. Peel strength test of the primer:

[0112] After the film coated with the primer is rolled and laminated with the base paper and cured (after completing step S2), the peel strength (unit: N / 25mm) of the primer coating is tested using a tensile testing machine at a peel angle of 180°. The test results are recorded.

[0113] 2. Glue overflow test

[0114] After the film coated with primer is rolled and laminated with the base paper and cured (after completing step S2), observe whether there is any glue overflow in the edge area of ​​the base paper and record the test results.

[0115] 3. Aluminum plating flatness test:

[0116] Referring to the test method in BB / T 0054-2010 Vacuum Metallized Paper, the flatness (unit: mm) of the metallized vacuum metallized paper (with adhesive applied to the uncoated side) was tested, and the test results were recorded.

[0117] 4. Folding endurance test of vacuum metallized paper:

[0118] Referring to the test method in GB / T 457-2008 Determination of Folding Endurance of Paper and Paperboard, the MIT folding endurance tester was used to test the folding endurance of vacuum metallized paper. When the vacuum metallized paper showed color splattering, the test was stopped, and the number of folding endurance tests (unit: times) was recorded.

[0119] The following are the performance test data of the vacuum metallized paper prepared in Examples 1-13 and Comparative Example 1, as detailed in Table 5 below.

[0120] Table 5. Test data of vacuum metallized composite paper prepared in Examples 1-13 and Comparative Example 1

[0121]

[0122]

[0123] Based on Examples 1-3 and Comparative Example 1, and in conjunction with Table 5, it can be concluded that heat-setting the base coating before roll lamination results in vacuum metallized paper with good folding endurance, high flatness of the metallization, and significantly improved adhesive overflow in the base coating.

[0124] Based on Examples 1-3 and 4-10 and Table 5, it can be concluded that the aqueous polyurethane prepolymer emulsion prepared by reacting the diisocyanate, polycaprolactone polyol, allyl glycidyl ether and 3-diethylenetriaminepropylmethyldimethoxysilane of this application, when applied to the base coating, exhibits good adhesion and high flatness on a smooth base paper surface, high flatness of the vacuum aluminized layer, and significantly improved folding endurance of the vacuum aluminized paper. Compared to Example 1, Example 4 shows an increase of 5.6 N / mm in peel strength of the base coating, an increase of 2.9 mm in the smoothness of the vacuum aluminized layer, and an increase of 95 folding cycles. This demonstrates that the base coating of this application significantly improves the performance stability and folding endurance of the vacuum aluminized paper compared to commercially available base coatings, and reduces the occurrence of color bursting. However, Examples 7-10, compared to Example 4, did not use the diisocyanate, polycaprolactone polyol, allyl glycidyl ether, and 3-diethylenetriaminepropylmethyldimethoxysilane of this application for combined use, which reduced the peel strength and coating uniformity of the resulting base coating. The peel strength was lower, the smoothness of the vacuum aluminized layer was lower, and the folding endurance of the resulting vacuum aluminized paper was also significantly reduced.

[0125] Based on Examples 4 and 11-13 and Table 5, it can be concluded that further compounding with the adhesion promoter and waterborne polyurethane prepolymer emulsion of this application can further improve the adhesion of the prepared base coating on the flat surface of the base paper, increase the peel strength by 1.2 N / mm, increase the flatness by 0.6 mm, and increase the number of folds by 25. This indicates that the adhesion promoter of this application has a good synergistic effect on improving the performance of the base coating of this application, which can improve the folding endurance and stability of the prepared vacuum metallized paper and further improve and reduce the color bursting problem.

[0126] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A dry-wet lamination process for vacuum metallized paper, characterized in that, The preparation steps include the following: S1. Apply a primer to the film and heat-set the side of the primer closest to the film. S2. The heat-set base coating is laminated with the base paper, and the base coating is cured to form a base coating on the surface of the base paper. S3. After peeling off the film, vacuum aluminum plating is performed on the side of the base coating away from the original paper to form a vacuum aluminum plating layer. S4. Apply adhesive to the side of the vacuum aluminized layer away from the base coating layer, and cure to form a top coating layer to obtain vacuum aluminized composite paper. The amount of the primer coating is 40-50 g / m². 2 The primer is made from the following percentages of raw materials: 30-50% waterborne polyurethane prepolymer emulsion Adhesion promoter 5-10% Wetting and dispersing agent 1-3% Hardener 2-4% Water balance; The aqueous polyurethane prepolymer emulsion is prepared by the following steps: A1. Add 40-60 parts of diisocyanate, 5-15 parts of polycaprolactone polyol, 3-8 parts of allyl glycidyl ether, 4-6 parts of 3-diethylenetriaminepropylmethyldimethoxysilane and 0.5-1.5 parts of catalyst to the reaction equipment, and react under vacuum to obtain polyurethane prepolymer. A2. Add 2-4 parts of hydrophilic chain extender to the polyurethane prepolymer obtained in step A1, and react under vacuum to obtain polyurethane chain extender prepolymer. A3. Add 2-5 parts of neutralizer, 3-5 parts of emulsifier and 20-30 parts of water to the polyurethane chain extender prepolymer obtained in step A2, and continue the reaction to obtain an aqueous polyurethane prepolymer emulsion. The adhesion promoter is composed of pentaerythritol triallyl ether and diaminosilane oligomer in a weight ratio of 1:(0.5-1); in step S1, the heat setting temperature is 90-110℃ and the heat setting time is 10-20s. The composite pressure in step S2 is 0.1-0.3 kPa, the curing time is 5-10 min, and the curing temperature is 80-100℃.

2. The dry-wet lamination process for vacuum metallized paper according to claim 1, characterized in that, The smoothness of the base paper is 400-600s.

3. The dry-wet lamination process for vacuum metallized paper according to claim 1, characterized in that, The reaction temperature in step A1 is 75-85℃, and the reaction time is 1-2 hours.

4. The dry-wet lamination process for vacuum metallized paper according to claim 1, characterized in that, The wetting and dispersing agent is any one or a combination of sodium polycarboxylate and ammonium polycarboxylate.

5. The dry-wet lamination process for vacuum metallized paper according to claim 1, characterized in that, The curing agent is an isocyanate-based curing agent.

Images