Water-based polymeric pressure-sensitive adhesive and label material containing said 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 in particular to water-based polymeric pressure-sensitive adhesives and label materials containing said pressure-sensitive adhesives. [Background technology]

[0002] In recent years, with the rapid development of packaging, transportation, materials, etc., the demand for label-type products has continued to increase, and the performance requirements for label products have also continued to change. Known and commonly used label materials include a polyester-based facestock, a water-based polymeric pressure-sensitive adhesive, and a substrate, which are adhered to each other from above. The manufacturing process involves coating the facestock with a pressure-sensitive adhesive, baking it, and then laminating the substrate and facestock to obtain a label material. The label material is then die-cut into finished labels of multiple specific sizes. The die-cutting process requires the facestock and pressure-sensitive adhesive layer to be cut, while the substrate must remain intact. To use the label, the facestock and pressure-sensitive adhesive are peeled from the substrate and then attached to the surface of the target application.

[0003] Currently, acrylic ester polymers, obtained by copolymerizing multiple acrylic ester monomers, are very important pressure-sensitive adhesives. Over the years, scientific researchers have continued to adjust the polymerization formulations and polymerization processes of acrylic ester pressure-sensitive adhesives 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, resulting in some adhesion to the substrate during label removal, making label removal difficult. Furthermore, some adhesive remains on the backing paper after label removal, affecting backing paper recycling. Furthermore, during die-cutting of label products, the pressure-sensitive adhesive has strong rebound resilience, which causes the adhesive to return to its original state after die-cutting, resulting in the glue flowing into the cutouts and causing sticking, resulting in label peeling. Summary of the Invention

[0004] In view of the above problems, the present invention provides an aqueous polymerizable pressure-sensitive adhesive that has strong adhesive strength when used with label materials, is easily cut when punching the label material, does not stick, has good removability, and does not stick to the substrate or leave glue on the backing paper when the label is peeled off.

[0005] The present invention further provides a label material comprising the water-based polymeric pressure-sensitive adhesive.

[0006] In a first aspect, the present invention provides a polymerizable composition comprising 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 ureido (meth)acrylate CHR 1 CH-COOR 2 2-8 parts of a cycloalkyl ester of methacrylic acid and 4-5 parts of a cycloalkyl ester of methacrylic acid, 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 A water-based polymeric pressure-sensitive adhesive is provided that is a cycloalkyl ester.

[0007] The water-soluble polyester may be prepared by adding 1-5 parts of a sulfonate salt for modifying the polyester, a hydroxyalkyl ester of (meth)acrylic acid (CHR), or a mixture of these. 3 CH-COOR 4 OH 10-15 parts, terephthalic acid 60-80 parts, ethylene glycol 20-30 parts, 3 is H or a methyl group, and R 4 is a straight or branched chain alkylene group having 2 to 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 radical having 1 to 4 carbon atoms, and a C4-C8 alkyl group refers to a linear or branched saturated hydrocarbon radical having 4 to 8 carbon atoms. Examples of C1-C4 alkyl groups are, for example, methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, or 1,1-dimethylethyl. Examples of C4-C8 alkyl groups are, for example, n-butyl, s-butyl, isobutyl, t-butyl, 2-methylpropyl, 1,1-dimethylethyl (t-butyl), pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, The term "cycloalkyl" as used herein includes, but is not limited to, cycloaliphatic groups, such as cyclohexyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, 2-heptyl, n-octyl, 2-octyl, and 2-ethylhexyl. As used herein, the term "cycloalkyl" refers to a monocyclic or bicyclic alicyclic group that is unsubstituted or substituted with one, two, three, or four methyl groups, and is particularly intended to include C5-C6 20 The total number of carbon atoms in the cycloalkyl group is 5 to 20, and C5-C 10 The total number of carbon atoms in the cycloalkyl group is 5 to 10. C5-C 20Examples of cycloalkyl groups include, but are not limited to, cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl, cyclododecyl, cyclohexadecyl, norbornyl (=bicyclo[2.2.1]heptyl) and isobornyl (=1,7,7-trimethylbicyclo[2.2.1]heptyl).

[0009] Preferably, the (meth)acrylic acid ureido CHR 1 CH-COOR 2 is ethylene urea ethyl methacrylate.

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

[0011] The sulfonate for modifying the polyester may be selected from sulfonates that are commonly used in the field of water-soluble polyesters in the prior art to modify polyesters to be water-soluble, such as 5-sodium dihydroxyethyl sulfoisophthalate.

[0012] Preferably, the cycloalkyl ester of methacrylic acid may be a cycloalkyl ester of a monocyclic or bicyclic structure, preferably a C5-C6 cycloalkyl ester of methacrylic acid. 10 Cycloalkyl esters, for example isobornyl methacrylate or norbornyl methacrylate.

[0013] The preparation of the water-soluble polyester and acrylic polymer may be carried out by methods commonly used in the prior art, and the specific process parameters can be determined by the engineer 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, the following methods are used: sulfonate for modifying polyester, hydroxyalkyl ester of (meth)acrylic acid CHR 3 CH-COOR 4 OH, terephthalic acid, and ethylene glycol are charged into a reactor, the temperature is raised to 120-125°C, a polycondensation initiator is added to carry out an esterification reaction, and after 3-3.5 hours of reaction, 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. The polycondensation initiator may be a conventional initiator, such as ethylene glycol antimony.

[0014] Specifically, the method for preparing the aqueous polymer pressure-sensitive adhesive includes the steps of: (1) Mixing a water-soluble polyester with a C1-C4 alkyl ester of methacrylic acid, a C4-C8 alkyl ester of acrylic acid, a ureido acrylate, a cycloalkyl ester of methacrylic acid, and a portion of deionized water, followed by stirring and emulsifying to obtain a monomer pre-emulsion with a solid content of 30%-50%; (2) After heating the second part, 50-100 parts by weight of deionized water, add 10%-20% of the monomer pre-emulsion obtained in step (1) to carry out a radical polymerization reaction, and then add the remaining pre-emulsion dropwise to carry out a radical polymerization reaction to obtain a product with a viscosity of 100-500 mPa·s.

[0015] Furthermore, the method for preparing the aqueous polymer pressure-sensitive adhesive includes the steps of: (1) Mixing a water-soluble polyester with a C1-C4 alkyl ester of methacrylic acid, a C4-C8 alkyl ester of acrylic acid, an acrylic acid ureide, a cycloalkyl ester of methacrylic acid, a portion of deionized water, and a radical initiator, followed by stirring and emulsifying to obtain a monomer pre-emulsion, wherein the weight of the initiator is 0.3%-0.8% of the total weight of the water-soluble polyester, the C1-C4 alkyl ester of methacrylic acid, a C4-C8 alkyl ester of acrylic acid, an acrylic acid ureide, and a cycloalkyl ester of methacrylic acid; (2) Heat the second portion of deionized water to 78-82°C, add 10-20% of the monomer pre-emulsion from step (1), and react for 15-25 minutes. Then, add the remaining monomer pre-emulsion dropwise over 2-5 hours. After the addition is complete, keep the mixture at 80-85°C for 1-2 hours, then lower the temperature to below 45°C and adjust the pH to 7-8. Finally, add a wetting agent and antifoaming agent, stir uniformly, and filter to obtain the aqueous polymer pressure-sensitive adhesive. The resulting pressure-sensitive adhesive has a concentration of 35-42%. During the incubation reaction step, a small amount of radical initiator may be added to allow the monomers to react completely.

[0016] The radical initiator, wetting agent, and antifoaming agent may be those commonly used in the art, for example, the radical initiator may be ammonium persulfate or potassium persulfate alone, or a redox initiator. Of course, as a matter of common sense, the oxidizing agent and reducing agent in the redox system are added separately, and the monomer pre-emulsion obtained in step (1) contains at most one of them, for example, only the oxidizing agent. The wetting agent is an alkyne glycol or an organosilicon, and the antifoaming agent is a mineral oil or an organosilicon.

[0017] In a second aspect, the present invention further provides a label material comprising the above-described water-based polymeric pressure-sensitive adhesive, the label material comprising a polyester base face material and the water-based polymeric pressure-sensitive adhesive adhered to each other.

[0018] In an embodiment of the present invention, the face material is prepared by polymerizing 40 to 60 parts of polyethylene glycol-1,4-cyclohexanedimethanol terephthalate (PETG), 15 to 35 parts of polyethylene glycol terephthalate (PET), 15 to 20 parts of polycarbonate, and 0.1 to 1.0 part of lubricant. Specifically, the PET, PETG, polycarbonate, and lubricant are mixed and melted, and then continuously cast. After that, the melt is subjected to uniaxial or biaxial stretching, and then rapidly cooled and molded to produce the face material. Preferably, the melt is continuously cast, then subjected to biaxial stretching at 3 to 5 times its original size, and then cooled to 25 to 55°C to produce the face material.

[0019] In a preferred embodiment, the number average molecular weight of PETG is 50,000 to 80,000 and the intrinsic viscosity is 0.80 to 0.85 dL / g, the number 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 number average molecular weight of polycarbonate is 20,000 to 35,000.

[0020] The lubricant may be any lubricant known in the art, and is preferably silica, glass beads, kaolin, or aluminum oxide.

[0021] When label materials are prepared by conventional techniques, the amount of silicon is 0.1-0.5 g / m 2 Silicon is applied to the substrate so as to control the adhesive strength, the water-based polymer pressure-sensitive adhesive is applied to the face material, the face material is baked, and then the substrate and the face material are stacked to form a label material, with the water-based polymer pressure-sensitive adhesive between the substrate and the face material, and the label material is die-cut into finished labels having a plurality of specific sizes.

[0022] The substrate may be made of a material commonly known in the art. For example, one method for preparing the substrate involves melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at two times its original size, and thermoforming it at 220°C.

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

[0024] 1. The water-based polymeric pressure-sensitive adhesive provided by the present invention can effectively improve the wetting, adhesion, and stickiness of the water-based polymeric pressure-sensitive adhesive to the face material, ensuring a strong bond between the face material and the pressure-sensitive adhesive during the label removal process, making it easy to peel the face material with the pressure-sensitive adhesive from the substrate, allowing for quick label removal, without the adhesive being too strong to the substrate, making label removal difficult, and without leaving any glue on the backing paper after the label is removed, which can affect the recycling of the backing paper. The inventors speculate that the reasons for this are as follows:

[0025] The aqueous polymer pressure-sensitive adhesive of the present invention incorporates a water-soluble polyester modification, which makes the molecular chain structure of the pressure-sensitive adhesive similar to that of the polyester surface material of the label. Based on the principle that similar substances dissolve well in each other, the adhesive is more compatible with the surface material and has better wettability. Furthermore, the hydrophilic sulfonic acid groups in the water-soluble polyester further improve the wettability of the aqueous polymer pressure-sensitive adhesive, thereby increasing the adhesive strength of the aqueous polymer pressure-sensitive adhesive to the surface material.

[0026] Water-soluble polyesters and acrylic acid polymers have poor compatibility. Therefore, if a water-soluble polyester is used to modify an acrylic acid polymer pressure-sensitive adhesive, such as by directly physically mixing the water-soluble polyester with the acrylic acid polymer or by polymerizing an acrylic acid monomer in the presence of the water-soluble polyester to obtain an acrylic acid polymer, the compatibility problem between the two cannot be solved, and the resulting pressure-sensitive adhesive mixture is likely to suffer from opacity and non-uniformity, both of which are unacceptable in the use of label materials. In the present invention, a (meth)acrylic acid hydroxyester monomer is cleverly introduced into the water-soluble polyester to introduce a double bond structure into the water-soluble polyester. The resulting water-soluble polyester undergoes radical copolymerization with the acrylic acid monomer, thereby modifying the acrylic acid polymer through a covalent bond in the polyester structure, thereby solving the compatibility problem between the two. This significantly improves the wettability and adhesion of the pressure-sensitive adhesive to polyester-based facings, and the resulting pressure-sensitive adhesive is transparent, uniform, and has stable and reliable performance.

[0027] By successfully selecting an acrylic acid ureido with suitable copolymerization activity, a ureido group structure can be introduced into the waterborne polymeric pressure-sensitive adhesive. The active hydrogen (H bonded to N) in the acrylic acid ureido can form hydrogen bond bridges with the ester groups in other components of the waterborne polymeric pressure-sensitive adhesive and the ester groups in the surface material, thereby improving the adhesive strength and adhesion of the pressure-sensitive adhesive to the surface material. When the ureido group-containing structure is a heterocyclic structure, it plays a significant role in increasing the aging resistance of the pressure-sensitive adhesive.

[0028] 2. The water-based polymer pressure-sensitive adhesive provided by the present invention can provide intermolecular forces (as described above), including hydrogen bonds. The high molecular crosslinking density and numerous crosslinking points improve the strength of internal crosslinks and increase the cohesive strength of the pressure-sensitive adhesive. Furthermore, the cycloalkyl ester of methacrylic acid can strongly inhibit the movement of polymer segments. This improves the hardness of the pressure-sensitive adhesive and reduces its rebound flow. When used as a label adhesive, this prevents adhesive threads from sticking during die-cutting and prevents them from rebounding and flowing into the cutouts after die-cutting, causing sticking. This prevents two adjacent die-cut labels from sticking to each other. With conventional labels, two adjacent labels stick together after die-cutting, necessitating the installation of a waste discharge section, resulting in the waste of a large amount of substrate and glue. In contrast, when the water-based polymeric pressure-sensitive adhesive provided by the present invention is used in labels, two adjacent labels are less likely to stick together during die-cutting, so there is no need to install a waste discharge section when die-cutting labels. This achieves zero label waste and avoids the problem of labels being unable to be peeled off or packaged due to the adhesion of adjacent labels during label use, thereby reducing label waste during use. DETAILED DESCRIPTION OF THE INVENTION

[0029] The following specific embodiments will be used to clearly and completely explain the technical solutions of the present invention, and it goes without saying that the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, any other embodiments that can be obtained by ordinary skilled artisans in this field without any creative work are all within the scope of protection of the present invention.

[0030] In the specific implementation of the present invention, the following raw materials are used: methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, butyl acrylate, 2-isooctyl 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.); 5-dihydroxyethyl sodium sulfoisophthalate (industrial grade, Jingmen Dongxi Biotechnology Co., Ltd.); polyethylene glycol terephthalate (PET) (molecular weight 72,000), polyethylene glycol-1,4-cyclohexanedimethanol terephthalate PETG (molecular weight 75,000) (industrial grade, Suzhou Aokai Polymer Materials Co., Ltd.); polycarbonate (industrial grade, Nantong Xingchen Synthetic Materials Co., Ltd.); ethylene glycol, lubricant (including silica, glass beads, kaolin, or aluminum oxide) (chemically pure, commercially available); ammonium persulfate, potassium persulfate (industrial grade, Degussa-AJ (Shanghai) Co., Ltd.); alkyne glycol wetting agent 104E (industrial grade, Shanghai Kuwai Chemical Co., Ltd.); organosilicon wetting agent 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 Hepufile New Materials Co., Ltd.).

[0031] In a first aspect, the present invention provides a polymerizable composition comprising 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 ureido (meth)acrylate CHR 1 CH-COOR 22-8 parts of a cycloalkyl ester of methacrylic acid and 4-5 parts of a cycloalkyl ester of methacrylic acid, 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 A water-based polymeric pressure-sensitive adhesive is provided that is a cycloalkyl ester.

[0032] The water-soluble polyester may comprise 1-5 parts of a sulfonate salt for modifying the polyester, a hydroxyalkyl ester of (meth)acrylic acid, CHR 3 CH-COOR 4 10-15 parts of hydroxyalkyl ester of (meth)acrylic acid, 60-80 parts of terephthalic acid, 20-30 parts of ethylene glycol, preferably 3 parts of sulfonic acid salt for polyester modification, CHR 3 CH-COOR 4 15 parts of OH, 80 parts of terephthalic acid, and 20 parts of ethylene glycol, except that R 3 is H or a methyl group, and R 4 is a straight or branched chain alkylene group having 2 to 5 carbon atoms.

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

[0034] The sulfonate for modifying the polyester may be selected from sulfonates that are commonly used in the field of water-soluble polyesters in the prior art to modify polyesters to be water-soluble, such as 5-sodium dihydroxyethyl sulfoisophthalate.

[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, and 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, particularly butyl acrylate and / or isooctyl acrylate, and 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)acrylic acid ureido CHR 1 CH-COOR 2 is ethylene urea ethyl methacrylate. 1 CH-COOR 2 The weight ratio of the raw material is 2 to 8 parts, preferably 5 parts.

[0038] Preferably, the cycloalkyl ester of methacrylic acid may be a cycloalkyl ester of a monocyclic or bicyclic structure, preferably a C5-C6 cycloalkyl ester 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 polymer may be carried out by methods commonly used in the prior art, and the specific process parameters can be determined by a technician through experimentation. Preferably, the viscosity of the water-soluble polyester is 5000-10000 mPa·s. Regarding the preparation method of the water-soluble polyester, specifically, the following methods are used: sulfonate for modifying polyester, hydroxyalkyl ester of (meth)acrylic acid CHR 3 CH-COOR 4 OH, terephthalic acid, and ethylene glycol are charged into a reactor, the temperature is raised to 120-125°C, a polycondensation initiator is added to carry out an esterification reaction, and after 3-3.5 hours of reaction, 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. The polycondensation initiator may be a conventional initiator, such as ethylene glycol antimony.

[0040] Specifically, the method for preparing the aqueous polymer pressure-sensitive adhesive includes the steps of: (1) Mixing a water-soluble polyester with a C1-C4 alkyl ester of methacrylic acid, a C4-C8 alkyl ester of acrylic acid, a ureido acrylate, a cycloalkyl ester of methacrylic acid, and a portion of deionized water, followed by stirring and emulsifying to obtain a monomer pre-emulsion with a solid content of 30%-50%; (2) After heating the second part, 50-100 parts by weight of deionized water, add 10%-20% of the monomer pre-emulsion obtained in step (1) to carry out a radical polymerization reaction, and then add the remaining pre-emulsion dropwise to carry out a radical polymerization reaction to obtain a product with a viscosity of 100-500 mPa·s.

[0041] It is common knowledge in this field that a radical initiator must be added to carry out the above-mentioned radical polymerization reaction, and the means for adding the radical initiator can be determined by the engineer according to the actual needs, and the radical initiator may be added in step (1) and added as part of the monomer pre-emulsion to the reaction system in step (2), or may be added dropwise together with the monomer pre-emulsion in step (2) or separately, etc. Explanation will be omitted here.

[0042] Furthermore, the method for preparing the aqueous polymer pressure-sensitive adhesive includes the steps of: (1) Mixing a water-soluble polyester with a C1-C4 alkyl ester of methacrylic acid, a C4-C8 alkyl ester of acrylic acid, an acrylic acid ureide, a cycloalkyl ester of methacrylic acid, a portion of deionized water, and a radical initiator, followed by stirring and emulsifying to obtain a monomer pre-emulsion, wherein the weight of the initiator is 0.3%-0.8% of the total weight of the water-soluble polyester, the C1-C4 alkyl ester of methacrylic acid, a C4-C8 alkyl ester of acrylic acid, an acrylic acid ureide, and a cycloalkyl ester of methacrylic acid; (2) Heat the second portion of deionized water to 78-82°C, add 10-20% of the monomer pre-emulsion from step (1), and react for 15-25 minutes. Then, add the remaining monomer pre-emulsion dropwise over 2-5 hours. After the addition is complete, keep the mixture at 80-85°C for 1-2 hours, then lower the temperature to below 45°C and adjust the pH to 7-8. Finally, add a wetting agent and antifoaming agent, stir uniformly, and filter to obtain the aqueous polymer pressure-sensitive adhesive. The resulting pressure-sensitive adhesive has a concentration of 35-42%. During the incubation reaction step, a small amount of radical initiator may be added to allow the monomers to react completely.

[0043] The radical initiator, wetting agent, and antifoaming agent may be those commonly used in the art, for example, the radical initiator may be ammonium persulfate or potassium persulfate alone, or a redox initiator. Of course, as a matter of common sense, the oxidizing agent and reducing agent in the redox system are added separately, and the monomer pre-emulsion obtained in step (1) contains at most one of them, for example, only the oxidizing agent. The wetting agent is an alkyne glycol or an organosilicon, and the antifoaming agent is a mineral oil or an organosilicon.

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

[0045] In a second aspect, the present invention further provides a label material comprising the above-described water-based polymeric pressure-sensitive adhesive, the label material comprising a polyester base face material and the water-based polymeric pressure-sensitive adhesive adhered to each other.

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

[0047] In particular, the method for preparing the water-soluble polyester was as follows: 70 g of terephthalic acid, 20 g of ethylene glycol, 3 g of 5-dihydroxyethyl sodium sulfoisophthalate, and 15 g of 4-hydroxybutyl acrylate were placed in a reactor, heated to 125°C, and 2 g of ethylene glycol antimony was added as an initiator. After 3 hours of esterification, the temperature was raised to 215°C to carry out a polycondensation reaction. After 5 hours of reaction, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 6,500 mPa·s.

[0048] In this example, a specific method for preparing the water-based polymeric 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 2-isooctyl acrylate, 50 g of ethylene urea ethyl methacrylate, 50 g of isobornyl methacrylate, 700 g of deionized water, and 2 g of ammonium persulfate were mixed, and then emulsified by stirring to obtain a monomer pre-emulsion liquid with a solid content of 38%.

[0050] (2) 100 g of deionized water was heated to 80°C, and 73.5 g of the monomer pre-emulsion obtained in step (1) was added. The mixture was allowed to react for 20 minutes. The remaining monomer pre-emulsion was then added dropwise over a 4-hour period. After the addition was complete, the mixture was kept at 80°C for 1 hour. The temperature was then lowered to below 45°C, and a pH adjuster was added to adjust the emulsion to a pH of 7-8. Finally, 1 g of an alkyne glycol wetting agent and 1 g of an organosilicon antifoaming agent were added, and the mixture was stirred uniformly and filtered to yield an aqueous polymer pressure-sensitive adhesive with a concentration of 35% and a viscosity of 150 mPa·s.

[0051] The label material was prepared with a silicone content of 0.35 g / m 2 The substrate was coated with silicone to control the temperature, and the face material was coated with the above-mentioned water-based polymer pressure-sensitive adhesive. After baking, the substrate and face material were laminated to form a label material. The label material was also die-cut into finished labels of several specific sizes. The face material was prepared by mixing (by weight) 50 parts amorphous transparent or white PETG, 30 parts PET, 19.5 parts polycarbonate, and 0.5 parts lubricant, melting the mixture, continuously casting it, biaxially stretching it at 4.4 times its original size, and rapidly cooling it at 30°C to form a mold. The lubricant was aluminum oxide. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at 2 times its original size, and thermoforming it at 220°C.

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

[0053] In particular, the method for preparing the water-soluble polyester was as follows: 70 g of terephthalic acid, 20 g of ethylene glycol, 3 g of 5-dihydroxyethyl sodium sulfoisophthalate, and 15 g of 4-hydroxybutyl acrylate were placed in a reactor, heated to 125°C, and 2 g of ethylene glycol antimony was added as an initiator. After 3 hours of esterification, the temperature was raised to 215°C to carry out a polycondensation reaction. After 5 hours of reaction, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 7600 mPa·s.

[0054] In this example, a specific method for preparing the water-based polymeric 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, 580 g of deionized water, and 2 g of ammonium persulfate were mixed, and then emulsified by stirring to obtain a monomer pre-emulsion liquid with a solid content of 40%.

[0056] (2) 80 g of deionized water was heated to 80°C, and 73.5 g of the monomer pre-emulsion obtained in step (1) was added. The mixture was allowed to react for 20 minutes. The remaining monomer pre-emulsion was then added dropwise over a 4-hour period. After the addition was complete, the mixture was kept at 80°C for 1 hour. The temperature was then lowered to below 45°C, and a pH adjuster was added to adjust the emulsion to a pH of 7-8. Finally, 1 g of an alkyne glycol wetting agent and 1 g of an organosilicon antifoaming agent were added, and the mixture was stirred uniformly and filtered to yield an aqueous polymer pressure-sensitive adhesive with a concentration of 38% and a viscosity of 120 mPa·s.

[0057] The label material was prepared with a silicone content of 0.35 g / m 2The substrate was coated with silicone to control the temperature, and the above-mentioned water-based polymer pressure-sensitive adhesive was applied to the face material. After baking, the substrate and face material were laminated to form a label material. The label material was also die-cut into finished labels of several specific sizes. The face material was prepared by mixing (by weight) 50 parts amorphous transparent or white PETG, 30 parts PET, 19.5 parts polycarbonate, and 0.5 parts lubricant, melting the mixture, continuously casting it, biaxially stretching it at 4.4 times its original size, and rapidly cooling it at 30°C to form a mold. The lubricant was silica. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at 2 times its original size, and thermoforming it at 220°C.

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

[0059] In particular, the method for preparing the water-soluble polyester was as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of 5-dihydroxyethyl sodium sulfoisophthalate, and 13 g of 4-hydroxybutyl acrylate were placed in a reactor, heated to 125°C, and 2 g of ethylene glycol antimony was added as an initiator. After 3 hours of esterification, the temperature was raised to 215°C to carry out a polycondensation reaction. After 5 hours of reaction, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 7,500 mPa·s.

[0060] In this example, a specific method for preparing the water-based polymeric 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, 600 g of deionized water, and 2 g of ammonium persulfate were mixed, and then emulsified by stirring to obtain a monomer pre-emulsion liquid with a solid content of 44%.

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

[0063] The label material was prepared with a silicone content of 0.35 g / m 2 The substrate was coated with silicone to control the temperature, and the above-mentioned water-based polymer pressure-sensitive adhesive was applied to the face material. After baking, the substrate and face material were laminated to form a label material. The label material was also die-cut into finished labels of several specific sizes. The face material was prepared by mixing (by weight) 50 parts amorphous transparent or white PETG, 30 parts PET, 19.5 parts polycarbonate, and 0.5 parts lubricant, melting the mixture, continuously casting it, biaxially stretching it at 4.4 times its original size, and rapidly cooling it at 30°C to form a mold. The lubricant was kaolin. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at 2 times its original size, and thermoforming it at 220°C.

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

[0065] In particular, the method for preparing the water-soluble polyester was as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of 5-dihydroxyethyl sodium sulfoisophthalate, and 12 g of 4-hydroxybutyl acrylate were placed in a reactor, heated to 125°C, and 2 g of ethylene glycol antimony was added as an initiator. After 3 hours of esterification, the temperature was raised to 215°C to carry out a polycondensation reaction. After 5 hours of reaction, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 7100 mPa·s.

[0066] In this example, a specific method for preparing the water-based polymeric 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, 620 g of deionized water, and 2 g of ammonium persulfate were mixed, and then emulsified by stirring to obtain a monomer pre-emulsion liquid with a solid content of 44%.

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

[0069] The label material was prepared with a silicone content of 0.35 g / m 2The substrate was coated with silicone to control the temperature, and the above-mentioned water-based polymer pressure-sensitive adhesive was applied to the face material. After baking, the substrate and face material were laminated to form a label material. The label material was also die-cut into finished labels of several specific sizes. The face material was prepared by mixing (by weight) 50 parts amorphous transparent or white PETG, 30 parts PET, 19.5 parts polycarbonate, and 0.5 parts lubricant, melting the mixture, continuously casting it, biaxially stretching it at 4.4 times its original size, and rapidly cooling it at 30°C to form a mold. The lubricant was silica. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at 2 times its original size, and thermoforming it at 220°C.

[0070] Comparative Example 1 In this comparative example, a water-based polymeric pressure-sensitive adhesive is provided that contains 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, the method for preparing the water-soluble polyester was as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of 5-dihydroxyethyl sodium sulfoisophthalate, and 15 g of 4-hydroxybutyl acrylate were placed in a reactor, heated to 125°C, and 2 g of ethylene glycol antimony was added as an initiator. After 3 hours of esterification, the temperature was raised to 215°C to carry out a polycondensation reaction. After 5 hours of reaction, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 8,500 mPa·s.

[0072] A specific method for preparing the water-based polymeric 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 emulsified by stirring to obtain a monomer pre-emulsion liquid with a solid content of 46.8%.

[0074] (2) 90 g of deionized water was heated to 80°C, and 73.5 g of the monomer pre-emulsion obtained in step (1) was added. The mixture was allowed to react for 20 minutes. The remaining monomer pre-emulsion was then added dropwise over a 4-hour period. After the addition was complete, the mixture was kept at 80°C for 1 hour. The temperature was then lowered to below 45°C, and a pH adjuster was added to adjust the emulsion to a pH of 7-8. Finally, 1 g of an alkyne glycol wetting agent and 1 g of an organosilicon antifoaming agent were added, and the mixture was stirred uniformly and filtered to yield an aqueous polymer pressure-sensitive adhesive with a concentration of 42.7% and a viscosity of 210 mPa·s.

[0075] The label material was prepared with a silicone content of 0.35 g / m 2 The substrate was coated with silicone to control the temperature, and the face material was coated with the above-mentioned water-based polymer pressure-sensitive adhesive. After baking, the substrate and face material were laminated to form a label material. The label material was also die-cut into finished labels of several specific sizes. The face material was prepared by mixing (by weight) 50 parts amorphous transparent or white PETG, 30 parts PET, 19.5 parts polycarbonate, and 0.5 parts lubricant, melting the mixture, continuously casting it, biaxially stretching it at 4.4 times its original size, and rapidly cooling it at 30°C to form a mold. The lubricant was aluminum oxide. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at 2 times its original size, and thermoforming it at 220°C.

[0076] Comparative Example 2 In this comparative example, a water-based polymeric pressure-sensitive adhesive is provided that contains 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, the method for preparing the water-soluble polyester was as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, and 3 g of 5-dihydroxyethyl sodium sulfoisophthalate were placed in a reactor, heated to 125°C, and 2 g of ethylene glycol antimony was added as an initiator. After 3 hours of esterification, the temperature was raised to 215°C to carry out a polycondensation reaction. After 5 hours of reaction, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 8200 mPa·s.

[0078] A specific method for preparing the water-based polymeric 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, 600 g of deionized water, and 2 g of ammonium persulfate were mixed, and then emulsified by stirring to obtain a monomer pre-emulsion liquid with a solid content of 47%.

[0080] (2) 100 g of deionized water was heated to 80°C, and 73.5 g of the monomer pre-emulsion obtained in step (1) was added. The mixture was allowed to react for 20 minutes. After the remaining monomer pre-emulsion was added dropwise over a 4-hour period, the mixture was kept at 80°C for 1 hour. The temperature was then lowered to 65°C and the mixture was allowed to react for 1 hour. The temperature was then lowered to below 45°C, and a pH adjuster was added to adjust the emulsion to a pH of 7-8. Finally, 1 g of an alkyne glycol wetting agent and 1 g of an organosilicon antifoaming agent were added, and the mixture was stirred 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] The label material was prepared with a silicone content of 0.35 g / m 2The substrate was coated with silicone to control the temperature, and the above-mentioned water-based polymer pressure-sensitive adhesive was applied to the face material. After baking, the substrate and face material were laminated to form a label material. The label material was also die-cut into finished labels of several specific sizes. The face material was prepared by mixing (by weight) 50 parts amorphous transparent or white PETG, 30 parts PET, 19.5 parts polycarbonate, and 0.5 parts lubricant, melting the mixture, continuously casting it, biaxially stretching it at 4.4 times its original size, and rapidly cooling it at 30°C to form a mold. The lubricant was kaolin. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at 2 times its original size, and thermoforming it at 220°C.

[0082] Comparative Example 3 In this comparative example, a water-based polymer pressure-sensitive adhesive is provided, 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 ureide (manufactured by Guangzhou Sanwang Chemical Materials Co., Ltd., model SW910), and 50 g of isobornyl methacrylate.

[0083] In particular, the method for preparing the water-soluble polyester was as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of 5-dihydroxyethyl sodium sulfoisophthalate, and 14 g of 4-hydroxybutyl acrylate were placed in a reactor, heated to 125°C, and 2 g of ethylene glycol antimony was added as an initiator. After 3 hours of esterification, the temperature was raised to 215°C to carry out a polycondensation reaction. After 5 hours of reaction, the mixture was discharged to obtain the water-soluble polyester with a viscosity of 7,400 mPa·s.

[0084] A specific method for preparing the water-based polymeric 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 acrylate ureide, 50 g of isobornyl methacrylate, 680 g of deionized water, and 2 g of ammonium persulfate were mixed, and then emulsified by stirring to obtain a monomer pre-emulsion liquid with a solid content of 44.2%.

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

[0087] The label material was prepared with a silicone content of 0.35 g / m 2 The substrate was coated with silicone to control the temperature, and the above-mentioned water-based polymer pressure-sensitive adhesive was applied to the face material. After baking, the substrate and face material were laminated to form a label material. The label material was also die-cut into finished labels of several specific sizes. The face material was prepared by mixing (by weight) 50 parts amorphous transparent or white PETG, 30 parts PET, 19.5 parts polycarbonate, and 0.5 parts lubricant, melting the mixture, continuously casting it, biaxially stretching it at 4.4 times its original size, and rapidly cooling it at 30°C to form a mold. The lubricant was silica. The substrate was obtained by melting polyethylene glycol terephthalate, continuously casting it, biaxially stretching it at 2 times its original size, and thermoforming it at 220°C.

[0088] Application experiment example The label materials prepared in Examples 1-4 and Comparative Examples 1-3 were each measured for initial tack, holding power, and 180° peel strength, and after die-cutting, the degree of adhesion between two adjacent label materials was observed. The results are shown in Table 1.

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

[0090] Table 1 Performance measurement results [Table 1]

[0091] From the above table, it can be seen that in Comparative Examples 1 and 3, when no ureido-group monomer was added to the aqueous polymeric pressure-sensitive adhesive or when a different type of ureido-group monomer was used, the crosslinking strength and cohesive strength of the aqueous polymeric pressure-sensitive adhesive were low, resulting in high initial tack, poor holding power, and poor peel strength, resulting in adhesion between the face material and the substrate when the label was peeled off. In Comparative Example 2, 4-hydroxybutyl acrylate was not added to the aqueous polymeric pressure-sensitive adhesive, resulting in poor wetting of the face material and poor adhesion. This resulted in poor holding power and peel strength of the label, resulting in adhesion between the face material and the substrate when the label was peeled off. The label materials prepared in Examples 1-4 had high compatibility between the water-based polymeric pressure-sensitive adhesive and the face stock, and the water-based polymeric pressure-sensitive adhesive had good wettability, adhesion, and stickiness to the face stock, as well as high crosslinking strength and cohesive strength, which gave the labels good initial tack, retention, and peel strength. The face stock and substrate did not stick together when the label was peeled, allowing for rapid label removal. After the label was peeled, no glue remained on the backing paper, which affected backing paper recycling. Furthermore, by increasing the internal crosslinking strength, the cohesive strength of the water-based polymeric pressure-sensitive adhesive was improved, increasing its hardness and reducing its rebound flow, preventing adhesive threads from sticking during die-cutting and preventing the adhesive from rebounding and flowing into the cutout after die-cutting, preventing two adjacent die-cut labels from sticking to each other. With conventional labels, two adjacent labels stick together after die-cutting, necessitating the installation of a waste disposal section, resulting in the waste of a large amount of substrate and glue. In contrast, when the water-based polymeric pressure-sensitive adhesive provided by the present invention is used in labels, two adjacent labels do not stick together during die-cutting, so there is no need to install a waste disposal section when die-cutting labels, thereby achieving zero label waste.

[0092] It goes without saying that the above-described examples are merely provided for clarity of explanation and are not intended to limit the scope of the present invention. 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 or necessary to list every possible embodiment here. Furthermore, any significant modifications or variations derived therefrom are within the scope of protection of the present invention.

Claims

1. Water-soluble polyester 4-6 parts, methacrylic acid C １ -C ４ 16-18 parts of alkyl ester, C of acrylic acid ４ -C ８ Alkyl ester 16-18 parts, (meth)acrylic acid ureido CHR １ CH-COOR ２ 2-8 parts of a cycloalkyl ester of methacrylic acid and 4-5 parts of a cycloalkyl ester of methacrylic acid, 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 C ５ -C ２０ is a cycloalkyl ester, The water-soluble polyester may comprise 1-5 parts of a sulfonic acid salt for modifying the polyester, a hydroxyalkyl ester of (meth)acrylic acid, CHR ３ CH-COOR ４ 10-15 parts of ethylene glycol, 60-80 parts of terephthalic acid, and 20-30 parts of ethylene glycol, ３ is H or a methyl group, and R ４ is a straight or branched chain alkylene group having 2 to 5 carbon atoms.

2. (Meth)acrylic acid ureido CHR １ CH-COOR ２ is ethylene urea ethyl methacrylate 2. The water-based polymeric pressure-sensitive adhesive of claim 1.

3. The hydroxyalkyl ester CHR of (meth)acrylic acid ３ CH-COOR ４ OH is 2-hydroxyethyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, or 4-hydroxybutyl acrylate 2. The water-based polymeric pressure-sensitive adhesive of claim 1.

4. The hydroxyalkyl ester CHR of (meth)acrylic acid ３ CH-COOR ４ OH is 4-hydroxybutyl acrylate 2. The water-based polymeric pressure-sensitive adhesive of claim 1.

5. The sulfonate salt for modifying the polyester is 5-dihydroxyethyl sodium sulfoisophthalate.

2. The water-based polymeric pressure-sensitive adhesive of claim 1.

6. The cycloalkyl ester of methacrylic acid is C ５ -C １０ It is a cycloalkyl ester 2. The water-based polymeric pressure-sensitive adhesive of claim 1.

7. The viscosity of the water-soluble polyester is 5000 to 10000 mPa·s.

2. The water-based polymeric pressure-sensitive adhesive of claim 1.

8. The method for preparing the water-based polymeric pressure-sensitive adhesive comprises: (1) C of water-soluble polyester and methacrylic acid １ -C ４ Alkyl ester, acrylic acid C ４ -C ８ The alkyl ester, (meth)acrylic acid ureide, cycloalkyl ester of methacrylic acid, and a portion of deionized water are mixed, and then emulsified by stirring to obtain a monomer pre-emulsion having a solid content of 30% to 50%; (2) Heat the second part of 50-100 parts by weight of deionized water, add 10%-20% of the monomer pre-emulsion obtained in step (1) to carry out a radical polymerization reaction, and then dropwise add the remaining pre-emulsion to carry out a radical polymerization reaction to obtain a product with a viscosity of 100-500 mPa·s.

2. The water-based polymeric pressure-sensitive adhesive of claim 1.

9. The method for preparing the water-based polymeric pressure-sensitive adhesive comprises: (1) C of water-soluble polyester and methacrylic acid １ -C ４ Alkyl ester, acrylic acid C ４ -C ８ The alkyl ester, (meth)acrylic acid ureide, cycloalkyl ester of methacrylic acid, a portion of deionized water, and a radical initiator are mixed and emulsified by stirring to obtain a monomer pre-emulsion. The weight of the initiator is the water-soluble polyester, C of methacrylic acid. １ -C ４ Alkyl ester, acrylic acid C ４ -C ８ 0.3% to 0.8% by weight of the total weight of the alkyl ester, (meth)acrylic acid ureide, and cycloalkyl ester of methacrylic acid; (2) Heat the second portion of deionized water to 78-82°C, add 10%-20% of the monomer pre-emulsion obtained in step (1), and react for 15-25 minutes. Then, add the remaining monomer pre-emulsion dropwise over a period of 2-5 hours. After the dropwise addition is complete, keep the temperature at 80-85°C for 1-2 hours, then lower the temperature to 45°C or below, adjust the pH to 7-8, and finally add a wetting agent and an antifoaming agent. Stir uniformly and filter to obtain an aqueous polymer pressure-sensitive adhesive.

2. The water-based polymeric pressure-sensitive adhesive of claim 1.

10. 10. A label material comprising the water-based polymeric pressure-sensitive adhesive of claim 1, comprising a polyester base face material and a water-based polymeric pressure-sensitive adhesive adhered together.

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