Aqueous polymerized pressure-sensitive adhesive and label material containing the pressure-sensitive adhesive

Abstract

The present invention provides a water-based polymerizable pressure-sensitive adhesive and a label material containing the pressure-sensitive adhesive. The pressure-sensitive adhesive exhibits strong adhesive strength when used in label materials, is easily cut when punching the label material, does not stick, and has good removability. The pressure-sensitive adhesive is prepared from 4-6 parts of a water-soluble polyester, 16-18 parts of a C1-C4 alkyl ester of methacrylic acid, 16-18 parts of a C4-C8 alkyl ester of acrylic acid, 2-8 parts of a (meth)acrylic acid ureide, and 4-5 parts of a cycloalkyl ester of methacrylic acid, with the proviso that R 1 is H or a methyl group, and R 2 is a linear or cyclic ureido group having 3-5 carbon atoms, and the cycloalkyl ester of methacrylic acid is C5-C 20 The water-soluble polyester is made from 1-5 parts of a sulfonate salt for modifying the polyester, 10-15 parts of a hydroxyalkyl ester of (meth)acrylic acid, 60-80 parts of terephthalic acid, and 20-30 parts of ethylene glycol.

Description

[Technical Field]

[0001] The present invention relates to the technical field of labels, and more particularly to aqueous polymerized pressure-sensitive adhesives and label materials containing the pressure-sensitive adhesive. [Background technology]

[0002] In recent years, with the rapid advancements in packaging, transportation, and materials, the demand for label products has continued to increase, and the performance requirements for label products have also continued to change. Commonly known label materials include a polyester-based facing material, an aqueous polymer pressure-sensitive adhesive, and a substrate, all bonded together from above. In the manufacturing process, the pressure-sensitive adhesive is coated onto the facing material, baked, and then the substrate and facing material are layered to obtain the label material. The label material is then die-cut into finished labels of various specific sizes. Die-cutting requires cutting the facing material and the pressure-sensitive adhesive layer, while maintaining the integrity of the substrate. When in use, the facing material and pressure-sensitive adhesive are peeled from the substrate and bonded to the surface of the application.

[0003] Currently, acrylic ester polymers obtained by copolymerizing multiple types of acrylic ester monomers are very important pressure-sensitive adhesives. With many years of development, scientific researchers have continued to adjust the polymerization formulations and polymerization processes of acrylic ester pressure-sensitive adhesive products and have introduced various functional monomers to further improve their performance. However, when such pressure-sensitive adhesives are used in label materials, problems arise, such as poor compatibility between the pressure-sensitive adhesive and the label surface material, resulting in insufficient adhesive strength. This causes the adhesive to stick to the substrate to some extent during label removal, preventing quick label removal. Furthermore, some adhesive remains on the backing paper after label removal, affecting backing paper collection. In addition, during die-cutting of label products, the strong rebound elasticity of the pressure-sensitive adhesive causes it to return to its original state after die-cutting. At that time, the glue flows into the cut edges, causing adhesion, resulting in sticking when removing the label. [Overview of the project]

[0004] In view of the above problems, the present invention provides an aqueous polymer pressure-sensitive adhesive which has a strong adhesive force when used for a label material, is easily cut when punching the label material, does not adhere, has good re-peelability, and does not adhere to the base material and leave glue on the backing paper when peeling the label.

[0005] The present invention further provides a label material containing the above aqueous polymer pressure-sensitive adhesive.

[0006] As a first aspect of the present invention, the present invention relates to an aqueous polymer pressure-sensitive adhesive obtained by polymerizing 4 - 6 parts of a water-soluble polyester, 16 - 18 parts of a C1 - C4 alkyl ester of methacrylic acid, 16 - 18 parts of a C4 - C8 alkyl ester of acrylic acid, 2 - 8 parts of a ureido (meth)acrylate CHR 1 CH-COOR 2 where R 1 is H or a methyl group, R 2 is a linear or cyclic ureido group having 3 - 5 carbon atoms, and the cycloalkyl ester of methacrylic acid is a C5 - C 20 cycloalkyl ester.

[0007] The above-mentioned water-soluble polyester is obtained by polymerizing 1 - 5 parts of a sulfonate for polyester modification, 10 - 15 parts of a hydroxyalkyl ester of (meth)acrylic acid CHR 3 CH-COOR 4 OH, 60 - 80 parts of terephthalic acid, and 20 - 30 parts of ethylene glycol, where R 3 is H or a methyl group, and R 4 is a linear or branched alkylene group having 2 - 5 carbon atoms.

[0008] In the present invention, "C n -C mThe term "alkyl group" refers to a linear or branched saturated hydrocarbon radical having n to m carbon atoms. For example, the term C1-C4 alkyl group refers to a linear or branched saturated hydrocarbon group having 1 to 4 carbon atoms, and the term C4-C8 alkyl group refers to a linear or branched saturated hydrocarbon group having 4 to 8 carbon atoms. Examples of C1-C4 alkyl groups include, for example, methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, or 1,1-dimethylethyl. Examples of C4-C8 alkyl groups include n-butyl, s-butyl, isobutyl, t-butyl, 2-methylpropyl, 1,1-dimethylethyl (t-butyl), pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, and 1-ethylpropyl. This includes, but is not limited to, C5-C 20 The total number of carbon atoms in a cycloalkyl group is 5 to 20, C5-C 10 The total number of carbon atoms in a cycloalkyl group is between 5 and 10. C5-C 20Examples of the cycloalkyl group include, but are not limited to, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, cyclohexadecyl group, norbornyl group (= bicyclo[2.2.1]heptyl group) and isobornyl group (= 1,7,7-trimethylbicyclo[2.2.1]heptyl group).

[0009] Preferably, the ureido (meth)acrylate CHR 1 CH-COOR 2 is ethyleneurea ethyl methacrylate.

[0010] Preferably, the hydroxyalkyl ester of the (meth)acrylic acid CHR 3 CH-COOR 4 OH is 2-hydroxyethyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate or 4-hydroxybutyl acrylate, and more preferably 4-hydroxybutyl acrylate.

[0011] The sulfonate for the polyester modification may be a sulfonate that water-solubilizes a polyester commonly used in the field of water-soluble polyesters in the prior art, for example, dihydroxyethyl 5-sodium sulfoisophthalate.

[0012] Preferably, the cycloalkyl ester of methacrylic acid may be a cycloalkyl ester having a monocyclic or bicyclic structure, preferably a C5-C 10 cycloalkyl ester of methacrylic acid, for example, isobornyl methacrylate or norbornyl methacrylate.

[0013] The preparation of the water-soluble polyester and the acrylic acid polymer may adopt the methods commonly used in this field in the prior art, and specific process parameters are determined by technicians through experiments. Preferably, the viscosity of the water-soluble polyester is 5000-10000 mPa·s. Regarding the preparation method of the water-soluble polyester, specifically, a sulfonate for polyester modification, a hydroxyalkyl ester of (meth)acrylic acid CHR 3 CH-COOR 4 OH, terephthalic acid, and ethylene glycol are added to a reaction kettle, the temperature is raised to 120-125 °C, a polycondensation reaction initiator is added to carry out an esterification reaction, and after reacting for 3-3.5 h, the temperature is raised to 210-215 °C, and the polycondensation reaction is carried out for 5-5.5 h to obtain a water-soluble polyester. For the above polycondensation reaction initiator, a normal initiator such as ethylene glycol antimony may be adopted.

[0014] Specifically, as the preparation method of the aqueous polymer pressure-sensitive adhesive, (1) After mixing the water-soluble polyester with a C1-C4 alkyl ester of methacrylic acid, a C4-C8 alkyl ester of acrylic acid, an acrylate ureide, a cycloalkyl ester of methacrylic acid, and the first part of deionized water, stir and emulsify to obtain a monomer pre-emulsion with a solid content of 30%-50%. (2) After heating 50-100 parts by weight of the second part of deionized water, add 10%-20% of the monomer pre-emulsion obtained in step (1), carry out a radical polymerization reaction, and then drop the remaining pre-emulsion to carry out a radical polymerization reaction to obtain a product with a viscosity of 100-500 mPa·s.

[0015] Furthermore, as the preparation method of the aqueous polymer pressure-sensitive adhesive, (1) A water-soluble polyester is mixed with C1-C4 alkyl esters of methacrylic acid, C4-C8 alkyl esters of acrylic acid, ureid acrylic acid, cycloalkyl esters of methacrylic acid, a portion of deionized water, and a radical initiator. The mixture is then stirred and emulsified to obtain a monomer pre-emulsified solution, wherein the weight of the initiator is 0.3%-0.8% of the total weight of the water-soluble polyester, C1-C4 alkyl esters of methacrylic acid, C4-C8 alkyl esters of acrylic acid, ureid acrylic acid, and cycloalkyl esters of methacrylic acid. (2) Heat the deionized water from the second part to 78-82°C, add 10%-20% of the monomer pre-emulsified solution obtained in step (1), and react for 15-25 minutes. Then, add the remaining monomer pre-emulsified solution dropwise over 2-5 hours. After the dropwise addition is complete, keep warm at 80-85°C for 1-2 hours, then cool to below 45°C, adjust the pH to 7-8, and finally add the humicant and defoamer. Stir uniformly and filter to obtain an aqueous polymer pressure-sensitive adhesive. The concentration of the obtained pressure-sensitive adhesive is 35%-42%. In addition, a small amount of radical initiator may be added during the heat retention reaction step to allow the monomers to react completely.

[0016] The radical initiator, humidifier, and defoamer mentioned above can be those commonly used in this field. For example, the radical initiator may be ammonium persulfate or potassium persulfate alone, or a redox initiator. Of course, as is common sense, the oxidizing agent and reducing agent in the redox system are added separately, and the monomer pre-emulsified liquid obtained in step (1) contains at most one type, for example, only the oxidizing agent. The humidifier is alkyne glycols or organosilicon compounds, and the defoamer is mineral oil or organosilicon compounds.

[0017] As a second aspect of the present invention, the present invention further provides a label material comprising the above-mentioned aqueous polymer pressure-sensitive adhesive, wherein the label material comprises a polyester base surface material and an aqueous polymer pressure-sensitive adhesive that are bonded to each other.

[0018] In the embodiments of the present invention, the above-mentioned surface material is obtained by polymerizing 40 to 60 parts polyethylene glycol-1,4-cyclohexanedimethanol terephthalate (PETG), 15 to 35 parts polyethylene glycol terephthalate (PET), 15 to 20 parts polycarbonate, and 0.1 to 1.0 part lubricant. Specifically, PET, PETG, polycarbonate, and lubricant are mixed and melted, then continuously cast, followed by uniaxial or biaxial tensioning, and then rapidly cooled and molded to create the surface material. Preferably, after continuous casting, biaxial tensioning is performed at 3 to 5 times the original tension, and then cooled at 25 to 55°C to mold the surface material.

[0019] In particular, a preferred embodiment is one in which the quantity-average molecular weight of PETG is 50,000 to 80,000 and the intrinsic viscosity is 0.80 to 0.85 dl / g, the quantity-average molecular weight of PET is 20,000 to 30,000 and the intrinsic viscosity is 0.62 to 0.67 dl / g, and the quantity-average molecular weight of polycarbonate is 20,000 to 35,000.

[0020] The above lubricants may be those commonly known and used in this art, and are preferably silica, glass beads, kaolin, or aluminum oxide.

[0021] When producing label materials using conventional technology, the amount of silicon is 0.1-0.5 g / m². 2 Silicone is applied to the substrate to control the pressure, the aqueous polymer pressure-sensitive adhesive is applied to the surface material, the surface material is baked, the substrate and surface material are stacked to form a label material, the aqueous polymer pressure-sensitive adhesive is between the substrate and the surface material, and the label material is die-cut into finished labels of multiple specific sizes.

[0022] The above-mentioned base material may be any material known and commonly used in this field. For example, one method for preparing the base material involves melting polyethylene glycol terephthalate, continuously casting it, then performing biaxial tensioning at twice its strength, and thermoforming it at 220°C.

[0023] The technical solution provided in this invention has the following advantages:

[0024] 1. The aqueous polymer pressure-sensitive adhesive provided in the present invention effectively improves the wetting ability, adhesion, and tackiness of the aqueous polymer pressure-sensitive adhesive to the surface material. During the label removal process, it firmly adheres the surface material and the pressure-sensitive adhesive, making it easy to peel the pressure-sensitive adhesive-coated surface material from the substrate, allowing for quick label removal. It also prevents the label from being difficult to remove due to excessive adhesion to the substrate, and prevents glue residue from remaining on the backing paper after label removal, thus avoiding interference with the collection of the backing paper. The inventor speculates that this is because:

[0025] The aqueous polymer pressure-sensitive adhesive according to the present invention enhances compatibility with the surface material and improves wettability by introducing a water-soluble polyester modification, thereby making the molecular chain structure of the pressure-sensitive adhesive similar to that of the polyester surface material of the label. This is based on the principle that similar materials dissolve well together. Furthermore, because the sulfonic acid groups in the water-soluble polyester are hydrophilic, the wettability of the aqueous polymer pressure-sensitive adhesive is further improved, thereby increasing the adhesive strength of the aqueous polymer pressure-sensitive adhesive to the surface material.

[0026] The compatibility between water-soluble polyesters and acrylic acid polymers is poor. Therefore, if water-soluble polyesters are used to modify acrylic acid polymer pressure-sensitive adhesives, either by directly physically mixing water-soluble polyesters and acrylic acid polymers, or by polymerizing acrylic acid monomers in the presence of water-soluble polyesters to obtain acrylic acid polymers, the compatibility problem between the two cannot be solved. The resulting pressure-sensitive adhesive mixture is prone to problems such as opacity and non-uniformity, and the two phenomena described above are unacceptable when used as a label material. In the present invention, by cleverly introducing (meth)acrylate hydroxyester monomers into water-soluble polyesters, a double bond structure is introduced into the water-soluble polyester. The resulting water-soluble polyester undergoes a radical copolymerization reaction with acrylic acid monomers, thereby modifying the acrylic acid polymers through covalent bonding in the polyester structure. This solves the compatibility problem between the two, significantly improving the wettability and adhesive strength of the pressure-sensitive adhesive to the polyester base material. The resulting pressure-sensitive adhesive is transparent, uniform, and has stable and reliable performance.

[0027] Successfully selecting an acrylic acid ureid with appropriate copolymerization activity and introducing the ureid group structure into an aqueous polymer pressure-sensitive adhesive. The active hydrogen (H bonded to N) in the acrylic acid ureid forms hydrogen-bonded crosslinks with ester groups in other components of the aqueous polymer pressure-sensitive adhesive and ester groups in the surface material, thereby improving the tackiness and adhesive strength of the pressure-sensitive adhesive to the surface material. Furthermore, if the ureid group-containing structure is heterocyclic, it plays a significant role in increasing the aging resistance of the pressure-sensitive adhesive.

[0028] 2. The aqueous polymer pressure-sensitive adhesive provided in the present invention can provide intermolecular forces, including hydrogen bonds (as described above), and has a high molecular crosslink density and many crosslinking points, thereby improving the strength of internal crosslinking and increasing the cohesive force of the pressure-sensitive adhesive. Furthermore, the cycloalkyl ester of methacrylic acid can strongly suppress the movement of polymer segments. As a result, the hardness of the pressure-sensitive adhesive is improved and its repulsive fluidity is reduced, and when used as a label adhesive, there is no adhesion of adhesive threads during die-cutting, and it is possible to avoid the adhesive repulsing and flowing into the notch after die-cutting and causing sticking, so that two adjacent die-cut labels do not stick to each other. Conventional labels require the installation of a waste disposal area because two adjacent die-cut labels stick together, resulting in the wasteful use of a large amount of substrate and glue. In contrast, the aqueous polymer pressure-sensitive adhesive provided in the present invention, when used for labels, does not easily adhere to two adjacent labels during die-cutting. Therefore, it is not necessary to install a waste disposal area when die-cutting labels, achieving zero label waste. Furthermore, it avoids problems such as label peeling or packaging failure due to the adhesion of adjacent labels during use, thereby reducing the waste of labels in use. [Modes for carrying out the invention]

[0029] The technical solutions of the present invention will be clearly and completely described below using specific embodiments, and it goes without saying that the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments that can be obtained by a person of the art without creative work based on the embodiments of the present invention are all within the scope of the present invention.

[0030] When specifically implementing the present invention, the following raw materials are used: methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, butyl acrylate, isooctyl 2-acrylate, ethylene urea ethyl methacrylate, isobornyl methacrylate, norbornyl methacrylate, 4-hydroxybutyl acrylate (industrial grade, Shanghai Yongzheng Chemical Co., Ltd.); terephthalic acid (industrial grade, Suzhou Plastics Co., Ltd.); dihydroxyethyl 5-sodium sulfisoisophthalate (industrial grade, Jingmen Dongxie Biotechnology Co., Ltd.); polyethylene glycol terephthalate (PET) (molecular weight 72000), polyethylene glycol-1,4-cyclohexanedimethanol terephthalate (PETG) (Molecular weight 75000) (Industrial grade, Suzhou Aokai Polymer Materials Co., Ltd.); Polycarbonate (Industrial grade, Nantong Xingchen Synthetic Materials Co., Ltd.); Ethylene glycol, lubricant (containing silica, glass beads, kaolin or aluminum oxide) (Chemically pure, commercially available); Ammonium persulfate, potassium persulfate (Industrial grade, DEGUSSA-AJ (SHANGHAI) Co., Ltd.); Alkyne glycol-coated humidifier 104E (Industrial grade, Shanghai Sangjing Chemical Co., Ltd.); Organosilicon-coated humidifier 122 (Industrial grade, Zhuhai Xiande New Materials Co., Ltd.); Organosilicon defoamer TSA-830 (Industrial grade, Jiangsu Tengda Auxiliary Agents Co., Ltd.); Mineral oil defoamer A-10 (Industrial grade, Tianjin Hepufeile New Materials Co., Ltd.).

[0031] As a first aspect of the present invention, the present invention comprises 4-6 parts of a water-soluble polyester, 16-18 parts of a C1-C4 alkyl ester of methacrylic acid, 16-18 parts of a C4-C8 alkyl ester of acrylic acid, and (meth)acrylic acid ureid CHR 1 CH-COOR 2It is formed by polymerizing 2-8 parts of a cycloalkyl ester of methacrylic acid, however, R 1 is H or a methyl group, R 2 The ureid group is a linear or cyclic ureid group having 3-5 carbon atoms, and the cycloalkyl ester of the methacrylic acid is C5-C 20 We provide an aqueous polymer pressure-sensitive adhesive that is a cycloalkyl ester.

[0032] The aforementioned water-soluble polyester contains 1-5 parts of a sulfonate for polyester modification and a hydroxyalkyl ester of (meth)acrylic acid CHR 3 CH-COOR 4 It is obtained by polymerizing 10-15 parts of OH, 60-80 parts of terephthalic acid, and 20-30 parts of ethylene glycol, preferably comprising 3 parts of a sulfonate for polyester modification and a hydroxyalkyl ester of (meth)acrylic acid CHR 3 CH-COOR 4 It is obtained by polymerizing 15 parts of OH, 80 parts of terephthalic acid, and 20 parts of ethylene glycol, however, R 3 is H or a methyl group, R 4 This is a linear or branched alkylene group having 2-5 carbon atoms.

[0033] Preferably, the hydroxyalkyl ester CHR of the (meth)acrylic acid. 3 CH-COOR 4 The OH group is 2-hydroxyethyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, or 4-hydroxybutyl acrylate, more preferably 4-hydroxybutyl acrylate.

[0034] The sulfonate used for polyester modification may be a sulfonate commonly used in the field of water-soluble polyesters in the prior art, such as dihydroxyethyl 5-sodium sulfisophthalate, which is used to modify polyesters to be water-soluble.

[0035] The C1-C4 alkyl ester of methacrylic acid includes, but is not limited to, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, s-butyl methacrylate, isobutyl methacrylate, or t-butyl methacrylate, particularly methyl methacrylate. The weight ratio of the C1-C4 alkyl ester of methacrylic acid to the raw material is 16 to 18 parts, preferably 17 parts.

[0036] The C4-C8 alkyl ester of acrylic acid includes, but is not limited to, at least one of butyl acrylate, pentyl acrylate, heptyl acrylate, and isooctyl acrylate, and is particularly specific to butyl acrylate and / or isooctyl acrylate. The weight ratio of the C4-C8 alkyl ester of acrylic acid to the raw material is 16 to 18 parts, preferably 17 parts.

[0037] Preferably, the (meth)acrylate ureid CHR 1 CH-COOR 2 This is ethylene urea ethyl methacrylate. The aforementioned (meth)acrylic acid ureid CHR 1 CH-COOR 2 The weight ratio of this to the raw materials is 2 to 8 parts, preferably 5 parts.

[0038] Preferably, the cycloalkyl ester of methacrylic acid may be a monocyclic or bicyclic cycloalkyl ester, preferably a C5-C of methacrylic acid. 10 The cycloalkyl ester is, for example, isobornyl methacrylate or norbornyl methacrylate. The weight ratio of the cycloalkyl ester of methacrylic acid to the raw material is 4 to 5 parts, preferably 5 parts.

[0039] The preparation of the water-soluble polyester and acrylic acid polymer can be carried out by employing methods commonly used in the art in the prior art, and the specific process parameters are determined experimentally by the engineer. Preferably, the viscosity of the water-soluble polyester is 5000-10000 mPa·s. Specifically, the method for preparing the water-soluble polyester involves the use of a sulfonate for polyester modification, and a hydroxyalkyl ester of (meth)acrylic acid CHR 3 CH-COOR 4 OH, terephthalic acid, and ethylene glycol are placed in a reaction vessel, the temperature is raised to 120-125°C, a polycondensation initiator is added to carry out the esterification reaction for 3-3.5 hours, and then the temperature is raised to 210-215°C and the polycondensation reaction is carried out for 5-5.5 hours to obtain a water-soluble polyester. For the polycondensation initiator, a common initiator such as ethylene glycol antimony can be used.

[0040] Specifically, as a method for preparing the aqueous polymer pressure-sensitive adhesive, (1) After mixing a water-soluble polyester with C1-C4 alkyl esters of methacrylic acid, C4-C8 alkyl esters of acrylic acid, ureid acrylate, cycloalkyl esters of methacrylic acid, and a portion of deionized water, the mixture is stirred and emulsified to obtain a monomer pre-emulsified liquid with a solid content of 30%-50%. (2) After heating 50-100 parts by weight of the second part of deionized water, 10%-20% of the monomer pre-emulsified solution obtained in step (1) is added and a radical polymerization reaction is carried out, and then the remaining pre-emulsified solution is added dropwise and a radical polymerization reaction is carried out to obtain a product with a viscosity of 100-500 mPa·s.

[0041] As is common knowledge in this field, a radical initiator is necessary to carry out the radical polymerization reaction described above. The method of adding the radical initiator can be determined by the engineer according to the actual needs. The radical initiator may be added in step (1) as part of the monomer pre-emulsifier and then introduced into the reaction system in step (2), or it may be added dropwise simultaneously with or separately from the monomer pre-emulsifier in step (2). Further explanation is omitted here.

[0042] Furthermore, as a method for preparing the aqueous polymer pressure-sensitive adhesive, (1) A water-soluble polyester is mixed with C1-C4 alkyl esters of methacrylic acid, C4-C8 alkyl esters of acrylic acid, ureid acrylic acid, cycloalkyl esters of methacrylic acid, a portion of deionized water, and a radical initiator. The mixture is then stirred and emulsified to obtain a monomer pre-emulsified solution, wherein the weight of the initiator is 0.3%-0.8% of the total weight of the water-soluble polyester, C1-C4 alkyl esters of methacrylic acid, C4-C8 alkyl esters of acrylic acid, ureid acrylic acid, and cycloalkyl esters of methacrylic acid. (2) Heat the deionized water from the second part to 78-82°C, add 10%-20% of the monomer pre-emulsified solution obtained in step (1), and react for 15-25 minutes. Then, add the remaining monomer pre-emulsified solution dropwise over 2-5 hours. After the dropwise addition is complete, keep warm at 80-85°C for 1-2 hours, then cool to below 45°C, adjust the pH to 7-8, and finally add the humicant and defoamer. Stir uniformly and filter to obtain an aqueous polymer pressure-sensitive adhesive. The concentration of the obtained pressure-sensitive adhesive is 35%-42%. In addition, a small amount of radical initiator may be added during the heat retention reaction step to allow the monomers to react completely.

[0043] The radical initiator, humidifier, and defoamer mentioned above can be those commonly used in this field. For example, the radical initiator may be ammonium persulfate or potassium persulfate alone, or a redox initiator. Of course, as is common sense, the oxidizing agent and reducing agent in the redox system are added separately, and the monomer pre-emulsified liquid obtained in step (1) contains at most one type, for example, only the oxidizing agent. The humidifier is alkyne glycols or organosilicon compounds, and the defoamer is mineral oil or organosilicon compounds.

[0044] The viscosity of the above-mentioned water-soluble polyester and water-soluble polymer pressure-sensitive adhesives is measured using a rotational viscometer. The rotational viscometer is commercially available, and the viscosity referred to in the following examples is specifically measured using an NDJ-5S digital rotational viscometer manufactured by Shanghai Jingqi Instruments Co., Ltd.

[0045] As a second aspect of the present invention, the present invention further provides a label material comprising the above-mentioned aqueous polymer pressure-sensitive adhesive, wherein the label material comprises a polyester base surface material and an aqueous polymer pressure-sensitive adhesive that are bonded to each other.

[0046] Example 1 This embodiment provides an aqueous polymer pressure-sensitive adhesive containing 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of ethylene urea ethyl methacrylate, and 50 g of isobornyl methacrylate.

[0047] In particular, as a method for preparing a water-soluble polyester, 70 g of terephthalic acid, 20 g of ethylene glycol, 3 g of dihydroxyethyl 5-sodium sulfisophthalate, and 15 g of hydroxybutyl acrylate were placed in a reaction vessel, the temperature was raised to 125°C, 2 g of ethylene glycol antimony was added as an initiator, and the esterification reaction was carried out for 3 hours. Then the temperature was raised to 215°C to carry out a polycondensation reaction, which was carried out for 5 hours, and after being discharged, the water-soluble polyester with a viscosity of 6500 mPa·s was obtained.

[0048] In this embodiment, the specific method for preparing the aqueous polymer pressure-sensitive adhesive includes the following steps.

[0049] (1) 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl 2-acrylate, 50 g of ethylene urea ethyl methacrylate, 50 g of isobornyl methacrylate, and 700 g of deionized water, and 2 g of ammonium persulfate were mixed and then stirred to emulsify and obtain a monomer pre-emulsified solution with a solid content of 38%.

[0050] (2) 100 g of deionized water was heated to 80°C, 73.5 g of monomer pre-emulsified solution obtained in step (1) was added and reacted for 20 min, then the remaining monomer pre-emulsified solution was added dropwise over 4 hours, and after the dropwise addition was complete, the mixture was kept warm at 80°C for 1 hour. The temperature was lowered to below 45°C, a pH adjuster was added to adjust the emulsion to pH 7-8, and finally 1 g of alkyne glycol-based wetting agent and 1 g of organosilicon-based defoaming agent were added, the mixture was mixed uniformly, and filtered to obtain an aqueous polymer pressure-sensitive adhesive with a concentration of 35% and a viscosity of 150 mPa·s.

[0051] For the preparation of the label material, the amount of silicon is 0.35 g / m². 2 Silicone was applied to the substrate to control the pressure, and the above-mentioned aqueous polymer pressure-sensitive adhesive was applied to the surface material. After baking, the substrate and surface material were layered to form the label material. The label material was also die-cut into finished labels of several specific sizes. In particular, for the preparation of the surface material, 50 parts (by weight) of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant were mixed, melted, and continuously cast, followed by biaxial tensile stress at 4.4 times and rapid cooling at 30°C to form the shape. The lubricant was aluminum oxide. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting, biaxial tensile stress at 2 times, and thermoforming at 220°C.

[0052] Example 2 This embodiment provides an aqueous polymer pressure-sensitive adhesive containing 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 30 g of ethylene urea ethyl methacrylate, and 50 g of isobornyl methacrylate.

[0053] In particular, as a method for preparing a water-soluble polyester, 70 g of terephthalic acid, 20 g of ethylene glycol, 3 g of dihydroxyethyl 5-sodium sulfisophthalate, and 15 g of 4-hydroxybutyl acrylate were placed in a reaction vessel, the temperature was raised to 125°C, 2 g of ethylene glycol antimony was added as an initiator, and the esterification reaction was carried out for 3 hours. Then the temperature was raised to 215°C to carry out a polycondensation reaction, which was carried out for 5 hours, and after being discharged, the water-soluble polyester with a viscosity of 7600 mPa·s was obtained.

[0054] In this embodiment, the specific method for preparing the aqueous polymer pressure-sensitive adhesive includes the following steps.

[0055] (1) 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 30 g of ethylene urea ethyl methacrylate, 50 g of isobornyl methacrylate, and 580 g of deionized water, and 2 g of ammonium persulfate were mixed and then stirred to emulsify and obtain a monomer pre-emulsified solution with a solid content of 40%.

[0056] (2) 80 g of deionized water was heated to 80°C, 73.5 g of monomer pre-emulsified solution obtained in step (1) was added and reacted for 20 min, then the remaining monomer pre-emulsified solution was added dropwise over 4 hours, and after the dropwise addition was complete, the mixture was kept warm at 80°C for 1 hour. The temperature was lowered to below 45°C, a pH adjuster was added to adjust the emulsion to pH 7-8, and finally 1 g of alkyne glycol-based wetting agent and 1 g of organosilicon-based defoaming agent were added, the mixture was mixed uniformly, and filtered to obtain an aqueous polymer pressure-sensitive adhesive with a concentration of 38% and a viscosity of 120 mPa·s.

[0057] For the preparation of the label material, the amount of silicon is 0.35 g / m². 2Silicone was applied to the substrate to control the pressure, the above-mentioned aqueous polymer pressure-sensitive adhesive was applied to the surface material, and after baking, the substrate and surface material were layered to form the label material. The label material was also die-cut into finished labels of several specific sizes. In particular, for the preparation of the surface material, 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant (by weight) were mixed, melted, and after continuous casting, biaxial tensile stress was performed at 4.4 times, and the material was molded by rapid cooling at 30°C. The lubricant was silica. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting, biaxial tensile stress at 2 times, and thermoforming at 220°C.

[0058] Example 3 This embodiment provides an aqueous polymer pressure-sensitive adhesive containing 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 30 g of ethylene urea ethyl methacrylate, and 50 g of isobornyl methacrylate.

[0059] In particular, as a method for preparing a water-soluble polyester, 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of dihydroxyethyl 5-sodium sulfisophthalate, and 13 g of hydroxybutyl acrylate were placed in a reaction vessel, the temperature was raised to 125°C, 2 g of ethylene glycol antimony was added as an initiator, and the esterification reaction was carried out for 3 hours. Then the temperature was raised to 215°C to carry out a polycondensation reaction, which was carried out for 5 hours, and the mixture was discharged to obtain the water-soluble polyester with a viscosity of 7500 mPa·s.

[0060] In this embodiment, the specific method for preparing the aqueous polymer pressure-sensitive adhesive includes the following steps.

[0061] (1) 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 30 g of ethylene urea ethyl methacrylate, 50 g of isobornyl methacrylate, and 600 g of deionized water and 2 g of ammonium persulfate were mixed and then stirred to emulsify and obtain a monomer pre-emulsified solution with a solid content of 44%.

[0062] (2) 90 g of deionized water was heated to 80°C, 73.5 g of monomer pre-emulsified solution obtained in step (1) was added and reacted for 20 min, then the remaining monomer pre-emulsified solution was added dropwise over 4 hours, and after the dropwise addition was complete, the mixture was kept warm at 80°C for 1 hour. The temperature was lowered to below 45°C, a pH adjuster was added to adjust the emulsion to pH 7-8, and finally 1 g of alkyne glycol-based wetting agent and 1 g of organosilicon-based defoaming agent were added, the mixture was stirred uniformly, and filtered to obtain an aqueous polymer pressure-sensitive adhesive with a concentration of 40.5% and a viscosity of 180 mPa·s.

[0063] For the preparation of the label material, the amount of silicon is 0.35 g / m². 2 Silicone was applied to the substrate to control the pressure, and the above-mentioned aqueous polymer pressure-sensitive adhesive was applied to the surface material. After baking, the substrate and surface material were layered to form the label material. The label material was also die-cut into finished labels of several specific sizes. In particular, for the preparation of the surface material, 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant (by weight) were mixed, melted, and after continuous casting, biaxial tensile stress was performed at 4.4 times, and the material was rapidly cooled at 30°C to form the shape. The lubricant was kaolin. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting, biaxial tensile stress at 2 times, and thermoforming at 220°C.

[0064] Example 4 This embodiment provides an aqueous polymer pressure-sensitive adhesive containing 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of ethylene urea ethyl methacrylate, and 50 g of isobornyl methacrylate.

[0065] In particular, as a method for preparing a water-soluble polyester, 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of dihydroxyethyl 5-sodium sulfisophthalate, and 12 g of hydroxybutyl acrylate were placed in a reaction vessel, the temperature was raised to 125°C, 2 g of ethylene glycol antimony was added as an initiator, and the esterification reaction was carried out for 3 hours. Then the temperature was raised to 215°C and the polycondensation reaction was carried out, and after the reaction was carried out for 5 hours, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 7100 mPa·s.

[0066] In this embodiment, the specific method for preparing the aqueous polymer pressure-sensitive adhesive includes the following steps.

[0067] (1) 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of ethylene urea ethyl methacrylate, 50 g of isobornyl methacrylate, and 620 g of deionized water and 2 g of ammonium persulfate were mixed and then stirred to emulsify and obtain a monomer pre-emulsified solution with a solid content of 44%.

[0068] (2) 60 g of deionized water was heated to 80°C, 73.5 g of monomer pre-emulsified solution obtained in step (1) was added and reacted for 20 min, then the remaining monomer pre-emulsified solution was added dropwise over 4 hours, and after the dropwise addition was complete, the mixture was kept warm at 80°C for 1 hour. The temperature was lowered to below 45°C, a pH adjuster was added to adjust the emulsion to pH 7-8, and finally 1 g of alkyne glycol-based wetting agent and 1 g of organosilicon-based defoaming agent were added, the mixture was stirred uniformly, and filtered to obtain an aqueous polymer pressure-sensitive adhesive with a concentration of 41.8% and a viscosity of 190 mPa·s.

[0069] For the preparation of the label material, the amount of silicon is 0.35 g / m². 2Silicone was applied to the substrate to control the pressure, the above-mentioned aqueous polymer pressure-sensitive adhesive was applied to the surface material, and after baking, the substrate and surface material were layered to form the label material. The label material was also die-cut into finished labels of several specific sizes. In particular, for the preparation of the surface material, 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant (by weight) were mixed, melted, and after continuous casting, biaxial tensile stress was performed at 4.4 times, and the material was molded by rapid cooling at 30°C. The lubricant was silica. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting, biaxial tensile stress at 2 times, and thermoforming at 220°C.

[0070] Comparative Example 1 This comparative example provides an aqueous polymer pressure-sensitive adhesive containing 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, and 50 g of isobornyl methacrylate.

[0071] In particular, as a method for preparing a water-soluble polyester, 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of dihydroxyethyl 5-sodium sulfisophthalate, and 15 g of hydroxybutyl acrylate were placed in a reaction vessel, the temperature was raised to 125°C, 2 g of ethylene glycol antimony was added as an initiator, and the esterification reaction was carried out for 3 hours. Then the temperature was raised to 215°C and the polycondensation reaction was carried out for 5 hours, after which the mixture was discharged to obtain the water-soluble polyester with a viscosity of 8500 mPa·s.

[0072] The specific preparation method for the aqueous polymer pressure-sensitive adhesive includes the following steps.

[0073] (1) 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of isobornyl methacrylate, 500 g of deionized water, and 2 g of ammonium persulfate were mixed and then stirred to emulsify and obtain a monomer pre-emulsified solution with a solid content of 46.8%.

[0074] (2) 90 g of deionized water was heated to 80°C, 73.5 g of monomer pre-emulsified solution obtained in step (1) was added and reacted for 20 min, then the remaining monomer pre-emulsified solution was added dropwise over 4 hours, and after the dropwise addition was complete, the mixture was kept warm at 80°C for 1 hour. The temperature was lowered to below 45°C, a pH adjuster was added to adjust the emulsion to pH 7-8, and finally 1 g of alkyne glycol-based wetting agent and 1 g of organosilicon-based defoaming agent were added, the mixture was mixed uniformly, and filtered to obtain an aqueous polymer pressure-sensitive adhesive with a concentration of 42.7% and a viscosity of 210 mPa·s.

[0075] For the preparation of the label material, the amount of silicon is 0.35 g / m². 2 Silicone was applied to the substrate to control the pressure, and the above-mentioned aqueous polymer pressure-sensitive adhesive was applied to the surface material. After baking, the substrate and surface material were layered to form the label material. The label material was also die-cut into finished labels of several specific sizes. In particular, for the preparation of the surface material, 50 parts (by weight) of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant were mixed, melted, and continuously cast, followed by biaxial tensile stress at 4.4 times and rapid cooling at 30°C to form the shape. The lubricant was aluminum oxide. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting, biaxial tensile stress at 2 times, and thermoforming at 220°C.

[0076] Comparative Example 2 This comparative example provides an aqueous polymer pressure-sensitive adhesive containing 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of ethylene urea ethyl methacrylate, and 50 g of isobornyl methacrylate.

[0077] In particular, as a method for preparing a water-soluble polyester, 75 g of terephthalic acid, 20 g of ethylene glycol, and 3 g of dihydroxyethyl 5-sodium sulfisophthalate were placed in a reaction vessel, the temperature was raised to 125°C, 2 g of ethylene glycol antimony was added as an initiator, and the esterification reaction was carried out for 3 hours. Then the temperature was raised to 215°C to carry out a polycondensation reaction, which was carried out for 5 hours, and the mixture was discharged to obtain the water-soluble polyester with a viscosity of 8200 mPa·s.

[0078] The specific preparation method for the aqueous polymer pressure-sensitive adhesive includes the following steps.

[0079] (1) 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of ethylene urea ethyl methacrylate, 50 g of isobornyl methacrylate, and 600 g of deionized water and 2 g of ammonium persulfate were mixed and then stirred to emulsify and obtain a monomer pre-emulsified solution with a solid content of 47%.

[0080] (2) 100 g of deionized water was heated to 80°C, 73.5 g of monomer pre-emulsified solution obtained in step (1) was added and the mixture was reacted for 20 mins, then the remaining monomer pre-emulsified solution was added dropwise over 4 hours, and after the addition was complete, the mixture was kept warm at 80°C for 1 hour. The temperature was lowered to 65°C and the mixture was kept warm and reacted for 1 hour. The temperature was lowered to below 45°C, a pH adjuster was added to adjust the pH of the emulsion to 7-8, and finally 1 g of alkyne glycol-based humectant and 1 g of organosilicon-based defoaming agent were added, the mixture was mixed uniformly, and filtered to obtain an aqueous polymer pressure-sensitive adhesive with a concentration of 43.5% and a viscosity of 240 mPa·s.

[0081] For the preparation of the label material, the amount of silicon is 0.35 g / m². 2Silicone was applied to the substrate to control the pressure, and the above-mentioned aqueous polymer pressure-sensitive adhesive was applied to the surface material. After baking, the substrate and surface material were layered to form the label material. The label material was also die-cut into finished labels of several specific sizes. In particular, for the preparation of the surface material, 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant (by weight) were mixed, melted, and after continuous casting, biaxial tensile stress was performed at 4.4 times, and the material was rapidly cooled at 30°C to form the shape. The lubricant was kaolin. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting, biaxial tensile stress at 2 times, and thermoforming at 220°C.

[0082] Comparative Example 3 This comparative example provides an aqueous polymer pressure-sensitive adhesive containing 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of modified hydroxyethyl acrylate ureid (manufactured by Guangzhou Sanwang Chemical Materials Co., Ltd., model SW910), and 50 g of isobornyl methacrylate.

[0083] In particular, as a method for preparing the water-soluble polyester, 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of dihydroxyethyl 5-sodium sulfisophthalate, and 14 g of hydroxybutyl acrylate were placed in a reaction vessel, the temperature was raised to 125°C, 2 g of ethylene glycol antimony was added as an initiator, and the esterification reaction was carried out for 3 hours. Then the temperature was raised to 215°C and the polycondensation reaction was carried out, and after the reaction was carried out for 5 hours, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 7400 mPa·s.

[0084] The specific preparation method for the aqueous polymer pressure-sensitive adhesive includes the following steps.

[0085] (1) 50 g of water-soluble polyester, 170 g of methyl methacrylate, 70 g of butyl acrylate, 100 g of isooctyl acrylate, 50 g of modified hydroxyethyl ureid acrylate, 50 g of isobornyl methacrylate, and 680 g of deionized water, and 2 g of ammonium persulfate were mixed and then stirred to emulsify and obtain a monomer pre-emulsified solution with a solid content of 44.2%.

[0086] (2) 80 g of deionized water was heated to 80°C, 73.5 g of monomer pre-emulsified solution obtained in step (1) was added and the mixture was reacted for 20 minutes, then the remaining monomer pre-emulsified solution was added dropwise over 4 hours, and after the addition was complete, the mixture was kept warm at 80°C for 1 hour. The temperature was lowered to 65°C and the mixture was kept warm and reacted for 1 hour. The temperature was lowered to below 45°C, a pH adjuster was added to adjust the pH of the emulsion to 7-8, and finally 1 g of alkyne glycol-based wetting agent and 1 g of organosilicon-based defoaming agent were added, the mixture was mixed uniformly, and filtered to obtain an aqueous polymer pressure-sensitive adhesive with a concentration of 41.5% and a viscosity of 170 mPa·s.

[0087] For the preparation of the label material, the amount of silicon is 0.35 g / m². 2 Silicone was applied to the substrate to control the pressure, the above-mentioned aqueous polymer pressure-sensitive adhesive was applied to the surface material, and after baking, the substrate and surface material were layered to form the label material. The label material was also die-cut into finished labels of several specific sizes. In particular, for the preparation of the surface material, 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant (by weight) were mixed, melted, and after continuous casting, biaxial tensile stress was performed at 4.4 times, and the material was molded by rapid cooling at 30°C. The lubricant was silica. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting, biaxial tensile stress at 2 times, and thermoforming at 220°C.

[0088] Examples of applied experiments For the label materials prepared in Examples 1-4 and Comparative Examples 1-3, the initial tack, holding power, and 180° peel strength were measured, respectively. After die-cutting, the degree of adhesion between two adjacent label materials was observed, and the results are shown in Table 1.

[0089] Measurement method: Initial tack is measured according to GB / T 31125-2014, "Test method for initial tack of pressure-sensitive adhesive tape (loop tack method)". Holding strength is measured according to GBT 4851-2014, "Test method for standard tape holding strength". 180° peel strength is measured according to GB / T 2792-2014, "Test method for tape peel strength".

[0090] Table 1 Performance Measurement Results [Table 1]

[0091] From the table above, it can be seen that in Comparative Examples 1 and 3, when ureido group monomers were not added to the aqueous polymer pressure-sensitive adhesive, or when different types of ureido group monomers were used, the crosslinking strength and cohesive force of the aqueous polymer pressure-sensitive adhesive were low, resulting in high initial tack of the label, low retention and peeling force, and the surface material and substrate becoming sticky when the label was peeled off. In Comparative Example 2, 4-hydroxybutyl acrylate was not added to the aqueous polymer pressure-sensitive adhesive, resulting in poor penetration of the aqueous polymer pressure-sensitive adhesive into the surface material and low adhesion. As a result, the label had low retention and peeling force, and the surface material and substrate became sticky when the label was peeled off. In the label materials prepared in Examples 1-4, the water-based polymer pressure-sensitive adhesive exhibited high compatibility with the surface material, good penetration, adhesion, and tackiness of the water-based polymer pressure-sensitive adhesive to the surface material, high crosslinking strength, and high cohesive force. As a result, the labels were able to be given good initial tack, retention, and peel strength. When peeling off the labels, the surface material and substrate did not stick together, allowing for quick label removal. After peeling off the labels, no glue remained on the backing paper, which affected the collection of the backing paper. Furthermore, by increasing the strength of internal crosslinking, the cohesive strength of the water-based polymer pressure-sensitive adhesive was improved, increasing the hardness of the pressure-sensitive adhesive and reducing its repulsive fluidity. This prevented the adhesive threads from sticking together during die-cutting, and avoided the adhesive repulsing and flowing into the notches after die-cutting, thus preventing two adjacent die-cut labels from sticking to each other. Conventional labels require the installation of a waste disposal area because two adjacent die-cut labels stick together, resulting in the wasteful use of a large amount of substrate and glue. In contrast, the aqueous polymer pressure-sensitive adhesive provided in the present invention, when used for labels, does not easily adhere to two adjacent labels during die-cutting. Therefore, it is not necessary to install a waste disposal area when die-cutting labels, and zero waste from labels can be achieved.

[0092] The embodiments described above are provided for illustrative purposes only and do not limit the embodiments. A person skilled in the art to which the present invention pertains can make various other modifications and variations based on the above description. It is not possible, nor is it necessary, to list all embodiments here. Furthermore, any significant modifications or variations derived therefrom fall within the scope of the present invention.

Claims

1. 4 - 6 parts of water-soluble polyester, C of methacrylic acid １ -C ４ 16 - 18 parts of C-alkyl ester of acrylic acid, C of acrylic acid ４ -C ８ 16 - 18 parts of C-alkyl ester of (meth)acrylic acid, ureido (meth)acrylate CHR １ CH - COOR ２ 2 - 8 parts, and 4 - 5 parts of cycloalkyl ester of methacrylic acid are polymerized, provided that R １ is H or a methyl group, R ２ is a linear or cyclic ureido group having 3 - 5 carbon atoms, and the cycloalkyl ester of methacrylic acid is C ５ -C ２０ cycloalkyl ester, The aforementioned water-soluble polyester contains 1-5 parts of a sulfonate for polyester modification and a hydroxyalkyl ester of (meth)acrylic acid CHR ３ CH-COOR ４ Obtained by polymerizing 10-15 parts of OH, 60-80 parts of terephthalic acid, and 20-30 parts of ethylene glycol, however, R ３ is H or a methyl group, R ４ An aqueous polymer pressure-sensitive adhesive characterized in that it is a linear or branched alkylene group having 2-5 carbon atoms.

2. The aforementioned (meth)acrylic acid ureid CHR １ CH-COOR ２ It is ethylene ureaethyl methacrylate. The aqueous polymer pressure-sensitive adhesive according to feature 1.

3. The hydroxyalkyl ester CHR of the aforementioned (meth)acrylic acid ３ CH-COOR ４ The OH group is 2-hydroxyethyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, or 4-hydroxybutyl acrylate. The aqueous polymer pressure-sensitive adhesive according to feature 1.

4. The hydroxyalkyl ester CHR of the aforementioned (meth)acrylic acid ３ CH-COOR ４ The OH group is 4-hydroxybutyl acrylate. The aqueous polymer pressure-sensitive adhesive according to feature 1.

5. The sulfonate used for the polyester modification is dihydroxyethyl 5-sodium sulfisophthalate. The aqueous polymer pressure-sensitive adhesive according to feature 1.

6. The cycloalkyl ester of methacrylic acid is C of methacrylic acid ５ -C １０ It is a cycloalkyl ester. The aqueous polymer pressure-sensitive adhesive according to feature 1.

7. The viscosity of the aforementioned water-soluble polyester is 5000-10000 mPa·s. The aqueous polymer pressure-sensitive adhesive according to feature 1.

8. The method for preparing the aqueous polymer pressure-sensitive adhesive is as follows: (1) C of water-soluble polyester and methacrylic acid １ -C ４ Alkyl esters, acrylic acid C ４ -C ８ After mixing alkyl ester, (meth)acrylic acid ureid, cycloalkyl ester of methacrylic acid, and a portion of deionized water, the mixture is stirred and emulsified to obtain a monomer pre-emulsified liquid with a solid content of 30%-50%. (2) After heating 50-100 parts by weight of the deionized water from the second part, 10-20% of the monomer pre-emulsified solution obtained in step (1) is added and a radical polymerization reaction is carried out, and then the remaining pre-emulsified solution is added dropwise and a radical polymerization reaction is carried out to obtain a product with a viscosity of 100-500 mPa·s. A method for preparing an aqueous polymer pressure-sensitive adhesive according to feature 1.

9. The method for preparing the aqueous polymer pressure-sensitive adhesive is as follows: (1) C of water-soluble polyester and methacrylic acid １ -C ４ Alkyl esters, acrylic acid C ４ -C ８ After mixing alkyl ester, (meth)acrylic acid ureid, cycloalkyl ester of methacrylic acid, a portion of deionized water, and a radical initiator, the mixture is stirred and emulsified to obtain a monomer pre-emulsified solution, where the weight of the initiator is that of a water-soluble polyester and methacrylic acid C １ -C ４ Alkyl esters, acrylic acid C ４ -C ８ The total weight of alkyl esters, (meth)acrylic acid ureids, and cycloalkyl esters of methacrylic acid is 0.3%–0.8%. (2) Heat the deionized water from the second part to 78-82°C, add 10-20% of the monomer pre-emulsified solution obtained in step (1), and react for 15-25 minutes. Then, add the remaining monomer pre-emulsified solution dropwise over 2-5 hours. After the dropwise addition is complete, keep warm at 80-85°C for 1-2 hours, then cool to below 45°C, adjust the pH to 7-8, and finally add alkyne glycols or organosilicon and an antifoaming agent. Stir uniformly and filter to obtain an aqueous polymer pressure-sensitive adhesive. A method for preparing an aqueous polymer pressure-sensitive adhesive according to feature 1.

10. A label material comprising an aqueous polymer pressure-sensitive adhesive as described in claim 1, characterized in that it comprises a polyester base surface material and an aqueous polymer pressure-sensitive adhesive that are bonded to each other.

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