A waterproof and wear-resistant label and its preparation process

Abstract

The present invention discloses a waterproof and wear-resistant label and its preparation process, belonging to the technical field of label paper. The waterproof and wear-resistant label includes a face paper, an adhesive, a film coating layer and a release base paper. The adhesive comprises raw materials in the following mass parts: 60-80 parts of acrylic monomers, 3-5 parts of multi-functional cross-linking monomers, 6-10 parts of siloxane-acrylate copolymer, 1-2 parts of initiator, 5-8 parts of nano-silica and 50-60 parts of solvent; the molecular chain of the siloxane-acrylate copolymer contains borate bonds. The siloxane long chain in the siloxane-acrylate copolymer has a low surface energy and can also help form a waterproof barrier, which can effectively prevent moisture from penetrating into the interface between the label and the product, greatly improving the waterproof property of the label; and the introduction of borate bonds can form a dynamic cross-linking network, improve stability, reinforce the label structure, improve wear resistance, and enable the label to closely adhere to the substrate in a long-term humid environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of label paper, and particularly relates to a waterproof and wear-resistant label and a preparation process thereof. Background Art

[0002] In modern packaging, label paper is an important material for information identification. At the same time, label paper also has multiple functions such as brand promotion, anti-counterfeiting, and functional protection. Therefore, it is widely used in many fields. For example, it is widely used in food packaging, daily chemical product packaging, and pharmaceutical packaging.

[0003] Among them, especially in food packaging and daily chemical product packaging, the products need to be in contact with water for a long time. For example, beer or other beverages are often cooled with ice water or refrigeration to improve the taste. After refrigeration, a large amount of water droplets will condense on the surface of the product at room temperature, or direct contact with ice water will damage the adhesive of the product label, resulting in a significant decrease in its adhesion and damaging the appearance of the product. Or the products need to be in a humid environment, such as shower gel, shampoo, or skin care products. Stored in a high-humidity environment for a long time, the moisture in the air will gradually penetrate into the label, causing adverse effects on the label paper. At the same time, frequent handling may cause the surface coating of the label to peel off or the pattern to become blurred.

[0004] To solve these problems, in order to enhance the waterproof performance of the label, the label materials widely used in the current market usually coat a waterproof coating on the surface of the label. However, the bonding force between this waterproof coating and the label paper is limited. When a large amount of water penetrates, the viscosity of the coating will decrease, and the wear resistance of the coating is not good, and it is easily damaged by friction, reducing the service life of the label. Summary of the Invention

[0005] The purpose of the present invention is to provide a waterproof and wear-resistant coating and a preparation process thereof to solve the problems of poor waterproof performance and weak anti-wear ability of label paper.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] In a first aspect, the present invention provides a waterproof and wear-resistant label, including a face paper, an adhesive, a film coating layer, and a release base paper. The adhesive includes the following raw materials in parts by mass:

[0008] Acrylic monomer 60 - 80 parts;

[0009] Multi-functional group cross-linking monomer 3 - 5 parts;

[0010] Siloxane-acrylate copolymer 6 - 10 parts;

[0011] Initiator 1 - 2 parts;

[0012] 5 to 8 parts of nano-silica;

[0013] 50 to 60 parts of solvent;

[0014] The molecular chain of the siloxane-acrylate copolymer contains borate bonds.

[0015] Preferably, the acrylic monomers include acrylic soft monomers and acrylic hard monomers with a mass ratio of (0.8 to 0.9):(0.1 to 0.2).

[0016] More preferably, the acrylic soft monomers include one or a combination of more than one of ethyl acrylate, butyl acrylate, isooctyl acrylate, n-octyl methacrylate, isobornyl acrylate, and octadecyl acrylate.

[0017] More preferably, the acrylic hard monomers include one or a combination of more than one of methyl methacrylate, glycidyl methacrylate, ethyl methacrylate, acrylic acid, and methacrylic acid.

[0018] Preferably, the polyfunctional crosslinking monomers include one or a combination of more than one of divinylbenzene, trimethylolpropane triacrylate, N,N'-methylenebisacrylamide, and pentaerythritol tetraacrylate.

[0019] Preferably, the initiators include one or a combination of more than one of benzoyl peroxide, di-tert-butyl peroxide, ammonium persulfate, azobisisobutyronitrile, benzoin ether, and benzoin dimethyl ether.

[0020] Preferably, the solvent includes one of alcohol solvents, ketone solvents, and ether solvents.

[0021] More preferably, the alcohol solvents include one of methanol, isopropanol, ethanol, and n-butanol; the ketone solvents include one of methyl ethyl ketone, acetone, cyclohexanone, and N-methylpyrrolidone; the ether solvents include one of ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and anisole.

[0022] By adopting the above technical solution, the acrylic soft monomer and the acrylic hard monomer, under the action of the multi-functional cross-linking monomer, provide good adhesion performance for the label paper. The addition of nano-silica can enhance the abrasion resistance of the label. In order to enhance the waterproof property of the label, a siloxane-acrylate copolymer is added to the adhesive. The siloxane chain segment in it is grafted onto the molecular chain of the acrylate, which can greatly improve the compatibility between the siloxane chain segment and the acrylic matrix, is conducive to the uniform dispersion of the siloxane chain segment and the formation of a uniform and dense protective film. The formed protective film can effectively prevent moisture from penetrating into the interface between the label and the product, improving the waterproof ability of the label. Moreover, the low surface energy of the siloxane itself makes the formed adhesive layer not easily wetted by moisture, further enhancing the waterproof effect. And the siloxane-acrylate copolymer has a long molecular chain, which can endow the adhesive with good flexibility. The acrylate chain segment can ensure the cohesion of the adhesive, enabling the label paper after waterproof treatment to also adhere well to products of different materials.

[0023] At the same time, the siloxane-acrylate copolymer has a long molecular chain segment. Compared with general siloxanes, such as silane coupling agents, the formed waterproof barrier can better block long-term moisture erosion and can also greatly optimize the compatibility with the acrylic matrix.

[0024] However, although adding only the siloxane-acrylate copolymer can improve the cohesion, it is easy to cause the interaction force between the internal molecular chains of the adhesive to increase accordingly, which is higher than the force with the substrate, and to a certain extent, it will reduce the peel strength between the label and the substrate. At the same time, the introduction of the long siloxane chain will affect the stability of the formed adhesive layer, bringing some material defects and affecting the service life of the label. To solve this problem, the molecular chain of the siloxane-acrylate copolymer of the present invention also contains borate bonds.

[0025] The introduction of borate bonds will significantly improve the bonding performance of the adhesive, and can also help form a more stable cross-linked network structure, which can interact with the siloxane chain segment. The formed Si-O-B cross-linked network can effectively improve the heat resistance and stability of the adhesive, improve the structural defects brought by the long-chain siloxane, and the borate bond can form a dynamic cross-linked network, enhancing the binding force with the substrate and the coating layer, and also bringing a certain self-healing ability to resist external pressure.

[0026] Preferably, the raw materials of the siloxane-acrylate copolymer include an acrylic compound, a monoacrylate-capped polysiloxane, and an aldehyde phenylboronic acid compound in a mass ratio of 100:(10 - 15):(2 - 3).

[0027] Preferably, the acrylic compound includes at least one hydroxy acrylic compound; the hydroxy acrylic compound includes one or a combination of two of hydroxyethyl methacrylate and hydroxypropyl methacrylate.

[0028] Preferably, the acrylic compound may also include one or a combination of multiple ones of methyl methacrylate, butyl acrylate, isooctyl acrylate, methacrylic acid, and isobornyl acrylate.

[0029] Preferably, the aldehyde group phenylboronic acid compound includes one or a combination of multiple ones of 4-formylphenylboronic acid, 3-formylphenylboronic acid, and 4-formyl-3,5-dimethoxyphenylboronic acid.

[0030] By adopting the above technical solution, the hydroxy acrylic compound adds new polar groups to the obtained acrylate copolymer, which can help with the polymerization between the polysiloxane and the aldehyde group phenylboronic acid compound. Finally, the obtained silicone-acrylate copolymer contains long-chain silicone segments, which can form a uniform and dense waterproof barrier, improving the waterproof property of the entire label paper.

[0031] The addition of the aldehyde group phenylboronic acid compound provides borate ester dynamic covalent bonds for the copolymer, which can coordinate the silicone long chains. The characteristics of the dynamic bonds enable the borate ester bonds to react with other oxygen-containing functional groups in the matrix, forming reversible crosslinking points. While endowing the material with self-healing ability, it can also help improve structural defects and improve the adhesion of the label, enabling the label to be closely attached to the substrate even in a long-term humid environment.

[0032] Preferably, the silicone-acrylate copolymer is prepared by the following method:

[0033] Add the aldehyde group phenylboronic acid compound to thionyl chloride, raise the temperature to 70 - 80 °C, and reflux for 10 - 12 h to obtain a pre-reaction monomer;

[0034] Raise the temperature of the solvent to 80 - 85 °C, add the acrylic compound, monoacrylate-capped polysiloxane, and initiator in a nitrogen atmosphere, stir and react for 2 - 3 h, then continue to add the initiator, and react for 2 - 3 h. After drying, a silicone-acrylate prepolymer is obtained;

[0035] Add the silicone-acrylate prepolymer and the pre-reaction monomer to the solvent respectively, mix the obtained solutions, add a catalyst, raise the temperature to 80 - 90 °C, keep the temperature for reaction for 10 - 12 h, and finally obtain the silicone-acrylate copolymer through filtration, washing, and drying.

[0036] Preferably, the initiator and the initiator in the adhesive raw materials are the same substance.

[0037] Preferably, the solvent comprises one or a combination of more of toluene, xylene and N,N-dimethylformamide.

[0038] Preferably, the catalyst comprises one of p-toluenesulfonic acid, sulfuric acid and hydrochloric acid.

[0039] By adopting the above technical solution, the acrylic compound first polymerizes under the action of an initiator and reacts with the monoacrylate-capped polysiloxane to be connected, and then an acetal reaction occurs between the monomer compound formed with the aldehyde group phenylboronic acid compound to form a borate bond.

[0040] Preferably, polydopamine is also grafted on the surface of the nano-silica; the mass ratio of the nano-silica to dopamine is 1:(1.5 - 2.5).

[0041] Preferably, the nano-silica grafted with dopamine is prepared by the following method:

[0042] Dissolve dopamine in Tris buffer solution, add nano-silica, stir and react at room temperature for 6 - 8 h, and finally obtain nano-silica grafted with dopamine through centrifugal separation, washing and drying.

[0043] By adopting the above technical solution, the addition of the nano-silica inorganic filler can improve the abrasion resistance of the label paper. However, due to the strong flexibility of the silicone-acrylate copolymer, the abrasion resistance of the label paper decreases accordingly. Therefore, in the present invention, the nano-silica is also modified by grafting polydopamine on the surface.

[0044] The molecular structure of dopamine contains amino and catechol groups. Among them, the amino group endows strong reactivity, thereby improving the dispersibility of nano-silica in the acrylic matrix, and can also react and crosslink with the acrylic matrix to enhance the crosslinking density of the adhesive; during the process of compounding the adhesive with the film coating layer, the adhesive containing dopamine can better penetrate into the surface micropores of the film coating layer to form a stronger interfacial bond, reinforce the label paper and improve the abrasion resistance of the label paper.

[0045] Moreover, the catechol group of dopamine can form strong bonding with the surfaces of various materials, and cooperate with the borate bond in the silicone-acrylate copolymer to dynamically crosslink in a humid environment, and can also provide stronger and more durable adhesion in a humid or underwater environment.

[0046] Preferably, the film coating layer comprises one of PET film, PP film and PE film.

[0047] In the second aspect, the present invention provides a preparation process for a waterproof and wear-resistant label, comprising the following process steps:

[0048] S1. Weigh the raw materials of the adhesive according to the corresponding mass parts, and stir and mix them for 3 to 4 hours to obtain the adhesive;

[0049] S2. Coating an ink layer on one side of the face paper, after drying, coating the obtained adhesive on the side of the face paper containing the ink layer, and then drying and hot-pressing and laminating a lamination layer through a laminator;

[0050] S3. Coating the adhesive on the other side of the face paper, and adhering it to the release base paper after drying to obtain a waterproof and wear-resistant label.

[0051] Advantages of the present invention:

[0052] 1. In the adhesive of the waterproof and wear-resistant label obtained in the present invention, a siloxane-acrylate copolymer is added. The long siloxane chain can help form a waterproof barrier, and the low surface energy of the siloxane itself also makes the formed adhesive layer difficult to be wetted by water, thereby effectively preventing water from penetrating into the interface between the label and the product, greatly improving the waterproofness of the label; in order to make up for the problem of the decrease in adhesion performance caused by the low intermolecular force of the siloxane, a borate bond is also introduced into the molecular chain of the siloxane-acrylate copolymer, which can form a dynamic crosslinking network, improve stability, and improve structural defects, so that the label can also be closely attached to the substrate in a long-term humid environment.

[0053] 2. In order to further improve the wear resistance and waterproofness of the label in the present invention, the nano-silica is also subjected to graft modification treatment. The grafted dopamine can increase the binding force with the lamination layer, strengthen the label, and improve the wear resistance of the label. At the same time, the catechol group in dopamine can also cooperate with the borate bond in the siloxane-acrylate copolymer to dynamically crosslink in a humid environment, providing a more stable and lasting adhesion force for the label in a humid environment. Specific embodiments

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0055] Preparation Example 1

[0056] Preparation Example 1-1, a siloxane-acrylate copolymer, is prepared according to the following method:

[0057] Add 2.5 g of 4-formylphenylboronic acid to 25 mL of thionyl chloride, raise the temperature to 70 °C, and reflux for 12 h to obtain a pre-reaction monomer;

[0058] Raise the temperature of 250 mL of toluene to 85 °C. Under a nitrogen atmosphere, add 100 g of an acrylic compound, 12 g of a monoacrylate-capped polysiloxane (model: Silok® 3821F3), and 0.3 g of ammonium persulfate. The acrylic compound is a mixture of 2-hydroxyethyl methacrylate and butyl acrylate with a mass ratio of 6:4. After stirring and reacting for 2 h, continue to add 0.1 g of ammonium persulfate and react for 2 h. After drying, a siloxane-acrylate prepolymer is obtained.

[0059] Add the obtained siloxane-acrylate prepolymer and the pre-reacted monomer to toluene respectively to prepare solutions with a mass fraction of 50%. Mix the obtained solutions, add 0.3 g of p-toluenesulfonic acid, raise the temperature to 85 °C, and keep the temperature for reaction for 12 h. Finally, after filtration, washing, and drying, a siloxane-acrylate copolymer is obtained.

[0060] Preparation Example 1-2, a siloxane-acrylate copolymer, which is only different from Preparation Example 1-1 in that the addition amount of 4-formylphenylboronic acid is 2 g; the addition amount of the monoacrylate-capped polysiloxane is 10 g.

[0061] Preparation Example 1-3, a siloxane-acrylate copolymer, which is only different from Preparation Example 1-1 in that the addition amount of 4-formylphenylboronic acid is 3 g; the addition amount of the monoacrylate-capped polysiloxane is 15 g.

[0062] Preparation Example 1-4, a siloxane-acrylate copolymer, which is only different from Preparation Example 1-1 in that the addition amount of the monoacrylate-capped polysiloxane is 5 g.

[0063] Preparation Example 1-5, a siloxane-acrylate copolymer, which is only different from Preparation Example 1-1 in that the addition amount of the monoacrylate-capped polysiloxane is 20 g.

[0064] Preparation Example 1-6, a siloxane-acrylate copolymer, which is prepared according to the following method:

[0065] Raise the temperature of 250 mL of toluene to 85 °C. Under a nitrogen atmosphere, add 100 g of an acrylic compound, 12 g of a monoacrylate-capped polysiloxane (model: Silok® 3821F3), and 0.3 g of ammonium persulfate. The acrylic compound is a mixture of 2-hydroxyethyl methacrylate and butyl acrylate with a mass ratio of 6:4. After stirring and reacting for 2 h, continue to add 0.1 g of ammonium persulfate and react for 2 h. After drying, a siloxane-acrylate copolymer is obtained.

[0066] Preparation Example 1-7, an acrylate copolymer, which is prepared according to the following method:

[0067] Add 2.5 g of 4-formylphenylboronic acid to 25 mL of thionyl chloride, raise the temperature to 70 °C, and reflux for 12 h to obtain a pre-reaction monomer;

[0068] Raise the temperature of 250 mL of toluene to 85 °C, add 100 g of acrylic compound and 0.2 g of ammonium persulfate in a nitrogen atmosphere. The acrylic compound is a mixture of 2-hydroxyethyl methacrylate and butyl acrylate with a mass ratio of 6:4. After stirring and reacting for 2 h, continue to add 0.1 g of ammonium persulfate and react for 2 h. After drying, an acrylate prepolymer is obtained;

[0069] Add the obtained acrylate prepolymer and pre-reaction monomer to toluene respectively, and prepare solutions with a mass fraction of 50%. Mix the obtained solutions, add 0.3 g of p-toluenesulfonic acid, raise the temperature to 85 °C, keep the temperature for reaction for 12 h, and finally obtain an acrylate copolymer through filtration, washing and drying.

[0070] Preparation Example 1-8, an acrylate copolymer, is prepared by the following method:

[0071] Raise the temperature of 250 mL of toluene to 85 °C, add 100 g of acrylic compound and 0.2 g of ammonium persulfate in a nitrogen atmosphere. The acrylic compound is a mixture of 2-hydroxyethyl methacrylate and butyl acrylate with a mass ratio of 6:4. After stirring and reacting for 2 h, continue to add 0.1 g of ammonium persulfate and react for 2 h. After drying, an acrylate copolymer is obtained.

[0072] Preparation Example 2

[0073] Preparation Example 2-1, a nano-silica, is subjected to graft modification treatment by the following method:

[0074] Dissolve 20 g of dopamine in 600 mL of Tris buffer solution, add 10 g of nano-silica (average particle size is 30 nm), stir and react at room temperature for 6 h, and finally obtain nano-silica grafted with dopamine through centrifugal separation, washing and drying.

[0075] Example

[0076] Example 1, a waterproof and wear-resistant label, is prepared by the following process steps:

[0077] S1. Weigh 70 parts of acrylic monomer, 4 parts of trimethylolpropane triacrylate, 8 parts of the silicone-acrylate copolymer prepared in Preparation Example 1-1, 1 part of azobisisobutyronitrile, 6 parts of nano-silica (average particle size is 30 nm) and 55 parts of isopropanol, and stir and mix for 4 h to obtain an adhesive; the acrylic monomer is a mixture of ethyl acrylate and methyl methacrylate with a mass ratio of 0.8:0.2;

[0078] S2. Coat an ink layer on one side of the facial tissue. After drying, coat the adhesive obtained on the side of the facial tissue with the ink layer, and then dry and hot-press laminate a PET film (with a thickness of 15 μm) through a laminating machine;

[0079] S3. Coat an adhesive on the other side of the facial tissue. After drying, adhere it to the release base paper to obtain a waterproof and wear-resistant label.

[0080] Examples 2 and 3, a waterproof and wear-resistant label, the difference from Example 1 is only that the raw material ratio of the adhesive is adjusted, as shown in Table 1 specifically:

[0081] Table 1 Adhesive formula table of Examples 1 to 3

[0082]

[0083] Among them, the acrylic monomers in Example 2 are a mixture of ethyl acrylate and methyl methacrylate with a mass ratio of 0.8:0.2; the acrylic monomers in Example 3 are a mixture of ethyl acrylate and methyl methacrylate with a mass ratio of 0.9:0.1.

[0084] Example 4, a waterproof and wear-resistant label, the difference from Example 1 is only that the addition amount of the silicone-acrylate copolymer prepared in Preparation Example 1-1 is 6 parts.

[0085] Example 5, a waterproof and wear-resistant label, the difference from Example 1 is only that the addition amount of the silicone-acrylate copolymer prepared in Preparation Example 1-1 is 10 parts.

[0086] Example 6, a waterproof and wear-resistant label, the difference from Example 1 is only that the silicone-acrylate copolymer prepared in Preparation Example 1-2 is used to replace the silicone-acrylate copolymer prepared in Preparation Example 1-1 in equal amounts.

[0087] Example 7, a waterproof and wear-resistant label, the difference from Example 1 is only that the silicone-acrylate copolymer prepared in Preparation Example 1-3 is used to replace the silicone-acrylate copolymer prepared in Preparation Example 1-1 in equal amounts.

[0088] Example 8, a waterproof and wear-resistant label, the difference from Example 1 is only that the silicone-acrylate copolymer prepared in Preparation Example 1-4 is used to replace the silicone-acrylate copolymer prepared in Preparation Example 1-1 in equal amounts.

[0089] Example 9, a waterproof and wear-resistant label, the difference from Example 1 is only that the silicone-acrylate copolymer prepared in Preparation Example 1-5 is used to replace the silicone-acrylate copolymer prepared in Preparation Example 1-1 in equal amounts.

[0090] Example 10. A waterproof and wear-resistant label, which is different from Example 1 only in that the nano-silica prepared in Preparation Example 2-1 is used to replace the nano-silica in Example 1 in an equal amount.

[0091] Comparative Example

[0092] Comparative Example 1. A waterproof and wear-resistant label, which is different from Example 1 only in that the addition amount of the siloxane-acrylate copolymer prepared in Preparation Example 1-1 is 3 parts.

[0093] Comparative Example 2. A waterproof and wear-resistant label, which is different from Example 1 only in that the addition amount of the siloxane-acrylate copolymer prepared in Preparation Example 1-1 is 12 parts.

[0094] Comparative Example 3. A waterproof and wear-resistant label, which is different from Example 1 only in that the siloxane-acrylate copolymer prepared in Preparation Example 1-6 is used to replace the siloxane-acrylate copolymer prepared in Preparation Example 1-1 in an equal amount.

[0095] Comparative Example 4. A waterproof and wear-resistant label, which is different from Example 1 only in that the acrylate copolymer prepared in Preparation Example 1-7 is used to replace the siloxane-acrylate copolymer prepared in Preparation Example 1-1 in an equal amount.

[0096] Comparative Example 5. A waterproof and wear-resistant label, which is different from Example 1 only in that the acrylate copolymer prepared in Preparation Example 1-8 is used to replace the siloxane-acrylate copolymer prepared in Preparation Example 1-1 in an equal amount.

[0097] Comparative Example 6. A waterproof and wear-resistant label, which is different from Example 1 only in that 3-aminopropyltriethoxysilane is used to replace the siloxane-acrylate copolymer prepared in Preparation Example 1-1 in an equal amount.

[0098] Performance Detection Test

[0099] Adhesion Test: The labels obtained in the examples and comparative examples are adhered to the PET board, naturally cooled after hot pressing for 1 h, and the peel strength of the adhesive film is tested.

[0100] Waterproof Test: The samples of the adhesion test are placed in an ice-water mixture for 30 min, and the peel strength of the adhesive film is tested continuously.

[0101] Wear Resistance Test: According to the relevant records in GB / T 6739-2022 "Paints and Varnishes - Determination of Film Hardness by the Pencil Method", the surface wear resistance of the labels in the examples and comparative examples is tested.

[0102] The above test results are shown in Table 2:

[0103] Table 2 Test Results of Performance Detection

[0104]

[0105] According to Example 1, Example 8, Example 9 and Comparative Example 4, it can be seen that the peel strength of Example 8, Example 9 and Comparative Example 4 decreased after immersion in ice water, and the decrease in Comparative Example 4 was the most obvious. The reason is that the only difference between Example 8, Example 9 and Comparative Example 4 compared with Example 1 is that the content of the siloxane segment in the added siloxane-acrylate copolymer was adjusted outside the required range. Among them, the addition amount of the siloxane segment was reduced in Example 8. Correspondingly, the waterproof property of the adhesive decreased. In a humid environment, the adhesive was greatly affected by moisture, and the adhesion decreased. In Comparative Example 4, the acrylate copolymer used did not contain a siloxane segment, and the performance decreased more significantly. In Example 9, the content of the monoacrylate-terminated polysiloxane in the siloxane-acrylate copolymer was increased, and the content of the siloxane segment increased. The introduction of a large number of low surface energy segments would cause the adhesion of the adhesive itself to decrease to some extent.

[0106] Combining Example 1 and Example 10, it can be seen that the adhesion, waterproof property and hardness of Example 10 were all enhanced compared with Example 1. The reason is that the nano-silica particles in Example 10 were grafted and modified with dopamine. The introduction of polar groups strengthened the bonding force between the adhesive and the substrate, and the catechol groups could cooperate with the borate bonds in the siloxane-acrylate copolymer to form a denser dynamic crosslinking network, which could not only improve the wear resistance, reduce the probability of water penetration, but also improve the adhesion under humid conditions.

[0107] Combining Example 1 and Comparative Example 3, it can be seen that the adhesion, waterproof property and hardness of Comparative Example 3 were all decreased compared with Example 1. The reason is that no borate bond was introduced into the siloxane-acrylate copolymer in Comparative Example 3. The structural defects and stability degradation brought by the long siloxane chain would both reduce the adhesion of the adhesive, and the adhesive was more likely to fail after immersion in ice water. At the same time, the absence of the borate bond also affected the crosslinking network in the adhesive, which would reduce the bonding force between the face paper and the laminating layer, resulting in a decrease in the reinforcement effect of the label and a decrease in wear resistance.

[0108] Combined with Example 1 and Comparative Example 6, it can be seen that the adhesion of Comparative Example 6 decreased significantly after being soaked in ice water, indicating that the waterproof property of Comparative Example 6 decreased significantly compared with that of Example 1. The reason is that in Comparative Example 6, the amino-silane coupling agent was used to replace the silicone-acrylate copolymer. In the natural state, the addition of the silane coupling agent does not affect the adhesion of the adhesive. However, compared with the silicone long chain, the siloxane segment in the silane coupling agent is short and it is difficult to form a tight waterproof barrier. After long-term soaking, the adhesion of the adhesive will decrease significantly. Moreover, the molecular weight of the silane coupling agent is low, and the formed adhesive layer will not enhance the reinforcement effect on the label and the wear resistance after combining with the film coating layer.

[0109] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0110] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A waterproof and wear-resistant label, comprising a face paper, an adhesive, a film coating layer and a release base paper, characterized in that, The adhesive comprises raw materials in the following parts by mass: 60 - 80 parts of acrylic monomer; 3 - 5 parts of multi - functional cross - linking monomer; 6 - 10 parts of siloxane - acrylate copolymer; 1 - 2 parts of initiator; 5 - 8 parts of nano - silica; 50 - 60 parts of solvent; The molecular chain of the siloxane - acrylate copolymer contains borate ester bonds; The raw materials of the siloxane - acrylate copolymer include an acrylic compound, a mono - acrylate - terminated polysiloxane, and an aldehyde - phenylboronic acid compound in a mass ratio of 100:(10 - 15):(2 - 3); The multi - functional cross - linking monomer includes one or a combination of more of divinylbenzene, trimethylolpropane triacrylate, N,N'-methylenebisacrylamide, and pentaerythritol tetraacrylate.

2. The waterproof and wear-resistant label according to claim 1, wherein The acrylic monomer includes an acrylic soft monomer and an acrylic hard monomer in a mass ratio of (0.8 - 0.9):(0.1 - 0.2).

3. The waterproof and wear-resistant label according to claim 1, characterized in that, The acrylic compound includes at least one hydroxy - acrylic compound; the hydroxy - acrylic compound includes one or a combination of two of 2 - hydroxyethyl methacrylate and 2 - hydroxypropyl methacrylate.

4. The waterproof and wear-resistant label according to claim 1, wherein The aldehyde - phenylboronic acid compound includes one or a combination of more of 4 - formylphenylboronic acid, 3 - formylphenylboronic acid, and 4 - formyl - 3,5 - dimethoxyphenylboronic acid.

5. The waterproof and wear-resistant label according to claim 1, wherein The siloxane - acrylate copolymer is prepared by the following method: Adding the aldehyde - phenylboronic acid compound to thionyl chloride, raising the temperature to 70 - 80 °C, and refluxing for 10 - 12 h to obtain a pre - reaction monomer; Raising the temperature of the solvent to 80 - 85 °C, adding the acrylic compound, the mono - acrylate - terminated polysiloxane, and the initiator in a nitrogen atmosphere, stirring and reacting for 2 - 3 h, then continuing to add the initiator, reacting for 2 - 3 h, and drying to obtain a siloxane - acrylate prepolymer; Adding the siloxane - acrylate prepolymer and the pre - reaction monomer to the solvent respectively, mixing the obtained solutions, adding a catalyst, raising the temperature to 80 - 90 °C, holding the temperature for 10 - 12 h, and finally obtaining the siloxane - acrylate copolymer through filtration, washing, and drying.

6. The waterproof and wear-resistant label according to claim 1, wherein The surface of the nano - silica is also grafted with dopamine; the mass ratio of the nano - silica to dopamine is 1:(1.5 - 2.5).

7. The waterproof and wear-resistant label according to claim 1, characterized in that, The coating layer includes one of a PET film, a PP film, and a PE film.

8. A preparation process of the waterproof and wear-resistant label according to any one of claims 1 to 7, characterized in that, It includes the following process steps: S1. Weigh the raw materials of the adhesive according to the corresponding parts by mass, stir and mix for 3 - 4 h to obtain the adhesive; S2. Coating an ink layer on one side of the face paper, after drying, coating the obtained adhesive on the side of the face paper with the ink layer, and then drying and hot - pressing to laminate a coating layer through a laminating machine; S3. Coating the adhesive on the other side of the face paper, after drying, adhering it to the release base paper to obtain a waterproof and wear - resistant label.

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