A water-based polymer pressure-sensitive adhesive and a label material containing the pressure-sensitive adhesive

Abstract

The present invention provides a water-based polymer pressure-sensitive adhesive and a label material containing the pressure-sensitive adhesive. The pressure-sensitive adhesive has strong adhesion when used for label materials, is easy to cut and does not stick when die-cutting the label materials, and has good re-peelability. 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 methacrylate, 16-18 parts of a C4-C8 alkyl ester of acrylic acid, 2-8 parts of a (meth)acrylic acid urea ester, and 4-5 parts of a cycloalkyl ester of methacrylate, wherein R 1 is H or methyl, R 2 is a linear or cyclic ureido group containing 3-5 carbon atoms, and the cycloalkyl ester of methacrylic acid is C5-C 20 Cycloalkyl ester, the water-soluble polyester is composed of 1-5 parts of sulfonate for polyester modification, 10-15 parts of hydroxyalkyl ester of (meth) acrylic acid, 60-80 parts of terephthalic acid, and 20-30 parts of ethylene glycol.

Description

Technical Field

[0001] The invention relates to the technical field of labels, and in particular to a water-based polymer pressure-sensitive adhesive and a label material containing the pressure-sensitive adhesive. Background Art

[0002] In recent years, due to the rapid development in packaging, transportation, materials, etc., the demand for label products has continued to expand, and the performance requirements for label products have also continued to change. A well-known and commonly used label material includes a polyester-based surface material, a water-based polymer pressure-sensitive adhesive, and a substrate that are bonded to each other from top to bottom. The production process is generally as follows: a pressure-sensitive adhesive is coated on the surface material, and after drying, the substrate and the surface material are compounded to obtain a label material; the label material is further die-cut into a plurality of finished labels of set sizes. During die-cutting, the surface material and the pressure-sensitive adhesive layer must be cut off, and the substrate needs to maintain its integrity. When in use, the surface material and the pressure-sensitive adhesive are removed from the substrate and attached to the surface of the application object.

[0003] Currently, acrylate polymers obtained by copolymerization of various types of acrylate monomers are a very important type of pressure-sensitive adhesive. After years of development, researchers have continuously adjusted the polymerization formula and polymerization process of acrylate pressure-sensitive adhesive products, and introduced a variety of functional monomers to improve their performance. Despite this, there are still a series of problems when this type of pressure-sensitive adhesive is used for label materials: for example, the pressure-sensitive adhesive has poor compatibility with the label surface material and insufficient adhesion, which leads to a certain degree of adhesion with the base material during the labeling process, making it impossible to complete the labeling quickly, and some residual glue will remain on the base paper after labeling, affecting the recycling of the base paper. In addition, when the label product is die-cut, due to the strong resilience of the pressure-sensitive adhesive, it will rebound to its original state after die-cutting. At this time, the glue at the incision position will flow to the incision position to produce gluing, resulting in adhesion during labeling. Summary of the invention

[0004] In view of this, the present invention provides a water-based polymer pressure-sensitive adhesive, which has strong adhesion when used for label materials, is easy to cut and does not stick when the label material is die-cut, has good removability, and will not stick to the base material when removing the label, so that residual adhesive will not be left on the base paper.

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

[0006] As a first aspect of the present invention, the present invention provides a water-based polymer pressure-sensitive adhesive, which is polymerized from the following raw materials in parts by weight: 4-6 parts of a water-soluble polyester, 16-18 parts of a C1-C4 alkyl ester of methacrylate, 16-18 parts of a C4-C8 alkyl ester of acrylic acid, and 16-18 parts of a (meth)acrylate urea base CHR 1 CH-COOR 2 2-8 parts, 4-5 parts of cycloalkyl methacrylate, wherein R1 is H or methyl, R 2 is a linear or cyclic ureido group containing 3 to 5 carbon atoms, and the cycloalkyl ester of methacrylic acid is C5-C 20 Cycloalkyl esters;

[0007] The water-soluble polyester is obtained by polymerizing the following raw materials in parts by weight: 1-5 parts of sulfonate for polyester modification, hydroxyalkyl (meth) acrylic acid ester CHR 3 CH-COOR 4 OH 10-15 parts, terephthalic acid 60-80 parts, ethylene glycol 20-30 parts, of which R 3 is H or methyl, R 4 It is a straight or branched chain alkylene group containing 2 to 5 carbon atoms.

[0008] In the present invention, the term "C n -C m "Alkyl" refers to a radical of a linear or branched saturated hydrocarbon radical having n to m carbon atoms. For example, the term C1-C4 alkyl refers to a radical of a linear or branched saturated hydrocarbon radical having 1 to 4 carbon atoms, and C4-C8 alkyl refers to a radical of a linear or branched saturated hydrocarbon radical having 4 to 8 carbon atoms. Examples of C1-C4 alkyl are methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl or 1,1-dimethylethyl. Examples of C4-C8 alkyl include, but are not limited to, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-methylpropyl, 1,1-dimethylethyl (tert-butyl), pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl The term "cycloalkyl" as used herein refers to a monocyclic or bicyclic alicyclic radical which is unsubstituted or substituted with 1, 2, 3 or 4 methyl radicals, wherein the C5-C6 radicals are substituted with 1, 2, 3 or 4 methyl radicals, and wherein the C5-C6 radicals are substituted with 1, 2, 3 or 4 methyl radicals. 20 The total number of carbon atoms in the cycloalkyl group is 5 to 20. 10 The total number of carbon atoms in the cycloalkyl group is from 5 to 10. 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)acrylate urea ester CHR 1 CH-COOR 2 It is ethylene urea ethoxy methacrylate.

[0010] Preferably, the hydroxyalkyl (meth)acrylate 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 used for modifying polyester can be selected from the sulfonates commonly used in the field of water-soluble polyesters in the prior art for modifying polyesters in water-soluble form, such as sodium bis(hydroxyethyl)isophthalate-5-sulfonate.

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

[0013] The water-soluble polyester and acrylic polymer can be prepared by the commonly used methods in the prior art. The specific process parameters can be determined by technicians based on experiments. Preferably, the viscosity of the water-soluble polyester is 5000-10000 mPa·s. Specifically, the following preparation method of the water-soluble polyester can be selected: sulfonate for polyester modification, hydroxyalkyl ester of (meth) acrylic acid CHR 3 CH-COOR 4 OH, terephthalic acid and ethylene glycol are put into a reaction kettle, the temperature is raised to 120-125°C, a polycondensation reaction initiator is added to carry out an esterification reaction, the reaction is carried out for 3-3.5 hours, the temperature is raised to 210-215°C, a polycondensation reaction is carried out, the reaction is carried out for 5-5.5 hours, and a water-soluble polyester is obtained. The polycondensation reaction initiator can be a conventional initiator, such as ethylene glycol antimony.

[0014] Specifically, the preparation method of the water-based polymer pressure-sensitive adhesive is:

[0015] (1) mixing a water-soluble polyester with a C1-C4 alkyl methacrylate, a C4-C8 alkyl acrylate, a ureido acrylate, a cycloalkyl methacrylate and a first portion of deionized water, and stirring and emulsifying to obtain a monomer pre-emulsion having a solid content of 30% to 50%;

[0016] (2) 50-100 parts by weight of the second portion of deionized water is heated and added to 10%-20% of the monomer pre-emulsion obtained in step (1) to carry out a free radical polymerization reaction, and then the remaining pre-emulsion is added dropwise to carry out a free radical polymerization reaction, and the viscosity of the obtained product is 100-500 mPa·s.

[0017] Furthermore, the preparation method of the water-based polymer pressure-sensitive adhesive is:

[0018] (1) mixing a water-soluble polyester with a C1-C4 alkyl methacrylate, a C4-C8 alkyl acrylate, a ureido acrylate, a cycloalkyl methacrylate, a first portion of deionized water, and a free radical initiator, and stirring and emulsifying to obtain a monomer pre-emulsion, wherein the weight of the initiator is 0.3% to 0.8% of the total weight of the water-soluble polyester, the C1-C4 alkyl methacrylate, the C4-C8 alkyl acrylate, the ureido acrylate, and the cycloalkyl methacrylate;

[0019] (2) Heat the second portion of deionized water to 78-82°C, add 10%-20% of the monomer pre-emulsion obtained in step (1), react for 15-25 minutes, then drop the remaining monomer pre-emulsion over a period of 2-5 hours, and keep the mixture at 80-85°C for 1-2 hours after the addition is complete; cool the mixture to below 45°C, adjust the pH value to 7-8, and finally add a wetting agent and a defoaming agent, stir evenly, and filter to obtain a water-based polymer pressure-sensitive adhesive. The concentration of the obtained pressure-sensitive adhesive is 35%-42%. Sometimes, a small amount of free radical initiator can be added during the heat preservation reaction stage to allow the monomer reaction to be complete.

[0020] The free radical initiator, wetting agent and defoamer can be selected from conventional methods in the art. For example, the free radical initiator can be ammonium persulfate or potassium persulfate alone; or a redox system initiator. Of course, as common sense, the oxidant and the reductant in the redox system should be added separately. In this case, the monomer pre-emulsion obtained in step (1) can contain at most one of them, for example, an oxidant; the wetting agent is an acetylenic diol or an organosilicon; and the defoamer is a mineral oil or an organosilicon.

[0021] As a second aspect of the present invention, the present invention also provides a label material comprising the above-mentioned water-based polymer pressure-sensitive adhesive, including a polyester-based surface material and a water-based polymer pressure-sensitive adhesive bonded to each other.

[0022] In an embodiment of the present invention, the surface material is polymerized by the following raw materials in parts by weight: 40 to 60 parts of polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG), 15 to 35 parts of polyethylene terephthalate (PET), 15 to 20 parts of polycarbonate, and 0.1 to 1.0 parts of a lubricant. Specifically, PET, PETG, polycarbonate, and a lubricant are mixed and melted, and after casting, they are stretched unidirectionally or bidirectionally, and quickly cooled and shaped to obtain the surface material. Preferably, after casting, they are stretched bidirectionally by 3 to 5 times, and cooled and shaped at 25 to 55°C to obtain the surface material.

[0023] Among them, as 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; the number average molecular weight of polycarbonate is 20,000 to 35,000.

[0024] The lubricant can be any material known in the art, preferably silicon dioxide, glass beads, kaolin or aluminum oxide.

[0025] When making label materials according to the prior art, silicon is coated on the base material, and the amount of silicon coating is controlled to be 0.1-0.5g / ㎡; the water-based polymer pressure-sensitive adhesive is coated on the surface material; after the surface material is dried, the base material and the surface material are compounded into a label material, and the water-based polymer pressure-sensitive adhesive is located between the base material and the surface material; the label material is die-cut into a plurality of finished labels with set sizes.

[0026] The substrate may be made of materials known in the art. For example, a method for preparing the substrate is as follows: polyethylene terephthalate is melted, cast into a sheet, biaxially stretched 2 times, and heat-set at 220°C.

[0027] The technical solution provided by the present invention has the following advantages:

[0028] 1. The water-based polymer pressure-sensitive adhesive provided by the present invention can effectively improve the wettability, adhesion and bonding of the water-based polymer pressure-sensitive adhesive to the surface material, so that the surface material and the pressure-sensitive adhesive are firmly attached together during the labeling process, and the surface material with the pressure-sensitive adhesive is easy to separate from the base material, so that the labeling can be completed quickly, avoiding excessive adhesion to the base material resulting in poor labeling, and no residual adhesive will be left on the base paper after labeling, avoiding affecting the recycling of the base paper. The inventor speculates that the reasons are as follows:

[0029] The water-based polymer pressure-sensitive adhesive of the present invention is modified by introducing a water-soluble polyester so that the molecular chain structure of the pressure-sensitive adhesive is similar to the polyester surface material of the label, and the compatibility with the surface material is improved according to the principle of like dissolves like, and the wettability to the surface material is improved; at the same time, the sulfonic acid group in the water-soluble polyester is hydrophilic, which can further improve the wettability of the water-based polymer pressure-sensitive adhesive, thereby improving the adhesion of the water-based polymer pressure-sensitive adhesive to the surface material.

[0030] Water-soluble polyesters have poor compatibility with acrylic polymers. Therefore, if the water-soluble polyester is directly physically mixed with the acrylic polymer, or the acrylic monomer is polymerized in the presence of the water-soluble polyester to obtain the acrylic polymer, the compatibility problem between the two cannot be solved by using the water-soluble polyester to modify the acrylic polymer pressure-sensitive adhesive. The resulting pressure-sensitive adhesive mixture is prone to problems of opacity and unevenness, both of which are not allowed during the use of label materials. The present invention cleverly introduces (methyl) hydroxyl acrylate monomers into the water-soluble polyester, thereby introducing a double bond structure into the water-soluble polyester. The resulting water-soluble polyester can undergo free radical copolymerization with the acrylic monomer, thereby modifying the acrylic polymer in a covalently bonded manner, solving the compatibility problem between the two, achieving a significant improvement in the wettability and adhesion of the pressure-sensitive adhesive to the polyester-based surface material, and the resulting pressure-sensitive adhesive is transparent and uniform, with reliable and stable performance.

[0031] We successfully selected urea acrylate with appropriate copolymerization activity and introduced the urea structure into the waterborne polymer pressure-sensitive adhesive. The active hydrogen (H connected to N) in the urea acrylate can undergo hydrogen bond cross-linking with the ester groups in other components of the waterborne polymer pressure-sensitive adhesive and the ester groups in the surface material to increase the adhesion and adhesion of the pressure-sensitive adhesive to the surface material. At the same time, when the urea-containing structure is a heterocyclic structure, it has a significant effect on improving the aging resistance of the pressure-sensitive adhesive.

[0032] 2. The water-based polymer pressure-sensitive adhesive provided by the present invention can provide an intermolecular force based on hydrogen bonds (as mentioned above), with a large molecular cross-linking density and many cross-linking points, which can improve the internal cross-linking strength and the cohesive force of the pressure-sensitive adhesive; the cycloalkyl ester of methacrylate has a strong inhibitory effect on the movement of polymer chain segments; thereby the hardness of the pressure-sensitive adhesive is improved and its rebound fluidity is reduced. When it is used as a label adhesive, there will be no adhesion of adhesive threads during the die-cutting process, and rebound after die-cutting will be avoided, and the flow to the incision position will produce adhesion, and the situation where two adjacent labels after die-cutting are adhered to each other will be avoided. Due to the problem of adhesion between two adjacent labels after die-cutting, traditional labels must set up a waste discharge interval, resulting in a large amount of substrate and glue waste. When the water-based polymer pressure-sensitive adhesive provided by the present invention is applied to labels, it is not easy for two adjacent labels to adhere during the die-cutting process, so that no waste discharge interval can be set when the label is die-cut, achieving zero label waste discharge, and also avoiding the problem of failure of labeling and packaging due to adhesion of adjacent labels when the label is used, reducing the waste of labels during use. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the specific implementation of the present invention, the raw materials used are as follows: methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, butyl acrylate, 2-isooctyl acrylate, ethylene urea ethoxy methacrylate, isobornyl methacrylate, norbornyl methacrylate, 4-hydroxybutyl acrylate, industrial grade, Shanghai Yongzheng Chemical Co., Ltd.; terephthalic acid, industrial grade, Suzhou Suyuxuan Plastic Co., Ltd.; sodium bis(hydroxyethyl)isophthalate-5-sulfonate, industrial grade, Jingmen Dongxin Biotechnology Co., Ltd.; polyethylene terephthalate (PET), molecular weight 72000, polyethylene terephthalate-1,4-cyclohexanedimethanol ester (PETG), Molecular weight is 75000, 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, Aijian Degussa (Shanghai) Co., Ltd.; acetylene glycol wetting agent 104E, industrial grade, Shanghai Sangjing Chemical Co., Ltd.; silicone wetting agent 122, industrial grade, Zhuhai Xiande New Materials Co., Ltd.; silicone defoamer TSA-830, industrial grade, Jiangsu Tengda Additive Co., Ltd.; mineral oil defoamer A-10, industrial grade, Tianjin Hepfill New Materials Co., Ltd.

[0035] As a first aspect of the present invention, the present invention provides a water-based polymer pressure-sensitive adhesive, which is polymerized from the following raw materials in parts by weight: 4-6 parts of a water-soluble polyester, 16-18 parts of a C1-C4 alkyl ester of methacrylate, 16-18 parts of a C4-C8 alkyl ester of acrylic acid, and 16-18 parts of a (meth)acrylate urea base CHR 1 CH-COOR 2 2-8 parts, 4-5 parts of cycloalkyl methacrylate, wherein R 1 is H or methyl, R 2 is a linear or cyclic ureido group containing 3 to 5 carbon atoms, and the cycloalkyl ester of methacrylic acid is C5-C 20 Cycloalkyl esters;

[0036] The water-soluble polyester is obtained by polymerizing the following raw materials in parts by weight: 1-5 parts of sulfonate for polyester modification, hydroxyalkyl (meth) acrylic acid ester CHR 3 CH-COOR 4 OH 10-15 parts, terephthalic acid 60-80 parts, ethylene glycol 20-30 parts, of which R 3 is H or methyl, R 4 is a straight or branched alkylene group containing 2 to 5 carbon atoms. Preferably, 3 parts of sulfonate for polyester modification, hydroxyalkyl (meth)acrylate CHR 3 CH-COOR 4 OH 15 parts, terephthalic acid 80 parts, ethylene glycol 20 parts.

[0037] Preferably, the hydroxyalkyl (meth)acrylate 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.

[0038] The sulfonate used for modifying polyester can be selected from the sulfonates commonly used in the field of water-soluble polyesters in the prior art for modifying polyesters in water-soluble form, such as sodium bis(hydroxyethyl)isophthalate-5-sulfonate.

[0039] 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, sec-butyl methacrylate, isobutyl methacrylate or tert-butyl methacrylate, especially methyl methacrylate. The weight proportion of the C1-C4 alkyl ester of methacrylic acid in the raw material is 16 to 18 parts, preferably 17 parts.

[0040] 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, especially butyl acrylate and / or isooctyl acrylate. The weight proportion of the C4-C8 alkyl ester of acrylic acid in the raw material is 16 to 18 parts, preferably 17 parts.

[0041] Preferably, the (meth)acrylate urea ester CHR 1 CH-COOR 2 It is ethylene urea ethoxy methacrylate. The (meth) urea ester CHR 1 CH-COOR 2 The weight proportion in the raw materials is 2 to 8 parts, preferably 5 parts.

[0042] Preferably, the cycloalkyl ester of methacrylic acid may be a cycloalkyl ester of a monocyclic or bicyclic structure, preferably a C5-C 10 Cycloalkyl esters, such as isobornyl methacrylate or norbornyl methacrylate. The weight proportion of the cycloalkyl ester of methacrylate in the raw material is 4 to 5 parts, preferably 5 parts.

[0043] The water-soluble polyester and acrylic polymer can be prepared by the commonly used methods in the prior art. The specific process parameters can be determined by technicians based on experiments. Preferably, the viscosity of the water-soluble polyester is 5000-10000 mPa·s. Specifically, the following preparation method of the water-soluble polyester can be selected: sulfonate for polyester modification, hydroxyalkyl ester of (meth) acrylic acid CHR 3 CH-COOR 4 OH, terephthalic acid and ethylene glycol are put into a reaction kettle, the temperature is raised to 120-125°C, a polycondensation reaction initiator is added to carry out an esterification reaction, the reaction is carried out for 3-3.5 hours, the temperature is raised to 210-215°C, a polycondensation reaction is carried out, the reaction is carried out for 5-5.5 hours, and a water-soluble polyester is obtained. The polycondensation reaction initiator can be a conventional initiator, such as ethylene glycol antimony.

[0044] Specifically, the preparation method of the water-based polymer pressure-sensitive adhesive is:

[0045] (1) mixing a water-soluble polyester with a C1-C4 alkyl methacrylate, a C4-C8 alkyl acrylate, a ureido acrylate, a cycloalkyl methacrylate and a first portion of deionized water, and stirring and emulsifying to obtain a monomer pre-emulsion having a solid content of 30% to 50%;

[0046] (2) 50-100 parts by weight of the second portion of deionized water is heated and added to 10%-20% of the monomer pre-emulsion obtained in step (1) to carry out a free radical polymerization reaction, and then the remaining pre-emulsion is added dropwise to carry out a free radical polymerization reaction, and the viscosity of the obtained product is 100-500 mPa·s.

[0047] As is common knowledge in the art, the free radical polymerization reaction described above requires the addition of a free radical initiator. The method of adding the free radical initiator can be determined by the technician according to actual needs. The free radical initiator can be added in step (1) and added to the reaction system of step (2) as part of the monomer pre-emulsion, or can be added dropwise simultaneously with the monomer pre-emulsion in step (2) or separately. No further details will be given here.

[0048] Furthermore, the preparation method of the water-based polymer pressure-sensitive adhesive is:

[0049] (1) mixing a water-soluble polyester with a C1-C4 alkyl methacrylate, a C4-C8 alkyl acrylate, a ureido acrylate, a cycloalkyl methacrylate, a first portion of deionized water, and a free radical initiator, and stirring and emulsifying to obtain a monomer pre-emulsion, wherein the weight of the initiator is 0.3% to 0.8% of the total weight of the water-soluble polyester, the C1-C4 alkyl methacrylate, the C4-C8 alkyl acrylate, the ureido acrylate, and the cycloalkyl methacrylate;

[0050] (2) Heat the second portion of deionized water to 78-82°C, add 10%-20% of the monomer pre-emulsion obtained in step (1), react for 15-25 minutes, then drop the remaining monomer pre-emulsion over a period of 2-5 hours, and keep the mixture at 80-85°C for 1-2 hours after the addition is complete; cool the mixture to below 45°C, adjust the pH value to 7-8, and finally add a wetting agent and a defoaming agent, stir evenly, and filter to obtain a water-based polymer pressure-sensitive adhesive. The concentration of the obtained pressure-sensitive adhesive is 35%-42%. Sometimes, a small amount of free radical initiator can be added during the heat preservation reaction stage to allow the monomer reaction to be complete.

[0051] The free radical initiator, wetting agent and defoamer can be selected from conventional methods in the art. For example, the free radical initiator can be ammonium persulfate or potassium persulfate alone; or a redox system initiator. Of course, as common sense, the oxidant and the reductant in the redox system should be added separately. In this case, the monomer pre-emulsion obtained in step (1) can contain at most one of them, for example, an oxidant; the wetting agent is an acetylenic diol or an organosilicon; and the defoamer is a mineral oil or an organosilicon.

[0052] The viscosity of the water-soluble polyester and water-based polymer pressure-sensitive adhesive is measured by a rotational viscometer. The rotational viscometer is commercially available, and the viscosity described in the following examples is specifically measured by a NDJ-5S digital display rotational viscometer produced by Shanghai Jingqi Instrument Co., Ltd.

[0053] As a second aspect of the present invention, the present invention also provides a label material comprising the above-mentioned water-based polymer pressure-sensitive adhesive, including a polyester-based surface material and a water-based polymer pressure-sensitive adhesive bonded to each other.

[0054] Example 1

[0055] This embodiment provides a water-based polymer pressure-sensitive adhesive, including the following raw materials: 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 ethoxy methacrylate, and 50 g of isobornyl methacrylate.

[0056] The preparation method of the water-soluble polyester is as follows: 70 g of terephthalic acid, 20 g of ethylene glycol, 3 g of sodium bis(hydroxyethyl)isophthalate-5-sulfonate and 15 g of 4-hydroxybutyl acrylate are put into a reaction kettle, the temperature is raised to 125° C., 2 g of initiator antimony ethylene glycol is added for esterification reaction, and after reacting for 3 hours, the temperature is raised to 215° C. for polycondensation reaction, and after reacting for 5 hours, the water-soluble polyester is obtained by discharging the material, and the viscosity is 6500 mPa·s.

[0057] In this embodiment, the specific preparation method of the water-based polymer pressure-sensitive adhesive includes the following steps:

[0058] (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 ethoxy methacrylate, 50 g of isobornyl methacrylate, 700 g of deionized water, and 2 g of ammonium persulfate were mixed, and stirred and emulsified to obtain a monomer pre-emulsion with a solid content of 38%;

[0059] (2) 100 g of deionized water was heated to 80° C., 73.5 g of the monomer pre-emulsion prepared in step (1) was added, and the mixture was reacted for 20 min. The remaining monomer pre-emulsion was then added dropwise over a period of 4 h. After the addition was completed, the mixture was kept at 80° C. for 1 h. The mixture was cooled to below 45° C., a pH regulator was added to adjust the pH value of the emulsion to 7-8, and finally 1 g of an acetylene glycol wetting agent and 1 g of an organosilicon defoaming agent were added. The mixture was stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive having a concentration of 35% and a viscosity of 150 mPa·s.

[0060] Preparation of label material: coating silicon on the base material, controlling the coating amount to 0.35g / ㎡, coating the above-mentioned water-based polymer pressure-sensitive adhesive on the surface material, and after drying, compounding the base material and the surface material into a label material; die-cutting the label material into multiple finished labels with set sizes. Among them, the surface material is prepared by the following method: (by weight) 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant are mixed and melted, and then cast into sheets and then biaxially stretched 4.4 times, and then rapidly cooled and shaped at 30°C. The lubricant is aluminum oxide; the base material is polyethylene terephthalate melted, and then cast into sheets and then biaxially stretched 2 times, and then heat-set at 220°C.

[0061] Example 2

[0062] This embodiment provides a water-based polymer pressure-sensitive adhesive, including the following raw materials: 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 ethoxy methacrylate, and 50 g of isobornyl methacrylate.

[0063] The preparation method of the water-soluble polyester is as follows: 70 g of terephthalic acid, 20 g of ethylene glycol, 3 g of sodium bis(hydroxyethyl)isophthalate-5-sulfonate and 15 g of 4-hydroxybutyl acrylate are put into a reaction kettle, the temperature is raised to 125° C., 2 g of initiator antimony ethylene glycol is added for esterification reaction, and after reacting for 3 hours, the temperature is raised to 215° C. for polycondensation reaction, and after reacting for 5 hours, the water-soluble polyester is obtained by discharging the material, and the viscosity is 7600 mPa·s.

[0064] In this embodiment, the specific preparation method of the water-based polymer pressure-sensitive adhesive includes the following steps:

[0065] (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 ethoxy methacrylate, 50 g of isobornyl methacrylate, 580 g of deionized water, and 2 g of ammonium persulfate were mixed, and stirred and emulsified to obtain a monomer pre-emulsion with a solid content of 40%;

[0066] (2) 80 g of deionized water was heated to 80° C., 73.5 g of the monomer pre-emulsion prepared in step (1) was added, and the mixture was reacted for 20 min. The remaining monomer pre-emulsion was then added dropwise over a period of 4 h. After the addition was completed, the mixture was kept at 80° C. for 1 h. The mixture was cooled to below 45° C., a pH regulator was added to adjust the pH value of the emulsion to 7 to 8, and finally 1 g of an acetylene glycol wetting agent and 1 g of an organosilicon defoaming agent were added. The mixture was stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive having a concentration of 38% and a viscosity of 120 mPa·s.

[0067] Preparation of label material: coating silicon on the base material, controlling the coating amount to 0.35g / ㎡, coating the above-mentioned water-based polymer pressure-sensitive adhesive on the surface material, and after drying, compounding the base material and the surface material into a label material; die-cutting the label material into multiple finished labels with set sizes. Among them, the surface material is prepared by the following method: (by weight) 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant are mixed and melted, and then cast into sheets and then biaxially stretched 4.4 times, and then rapidly cooled and shaped at 30°C. The lubricant is silicon dioxide; the base material is polyethylene terephthalate melted, and then cast into sheets and then biaxially stretched 2 times, and then heat-set at 220°C.

[0068] Example 3

[0069] This embodiment provides a water-based polymer pressure-sensitive adhesive, including the following raw materials: 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 ethoxy methacrylate, and 50 g of isobornyl methacrylate.

[0070] The preparation method of the water-soluble polyester is as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of sodium bis(hydroxyethyl)isophthalate-5-sulfonate and 13 g of 4-hydroxybutyl acrylate are put into a reaction kettle, the temperature is raised to 125° C., 2 g of initiator antimony ethylene glycol is added for esterification reaction, and after reacting for 3 hours, the temperature is raised to 215° C. for polycondensation reaction, and after reacting for 5 hours, the water-soluble polyester is obtained by discharging the material, and the viscosity is 7500 mPa·s.

[0071] In this embodiment, the specific preparation method of the water-based polymer pressure-sensitive adhesive includes the following steps:

[0072] (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 ethoxy methacrylate, 50 g of isobornyl methacrylate, 600 g of deionized water, and 2 g of ammonium persulfate were mixed, and stirred and emulsified to obtain a monomer pre-emulsion having a solid content of 44%;

[0073] (2) 90 g of deionized water was heated to 80° C., 73.5 g of the monomer pre-emulsion prepared in step (1) was added, and the mixture was reacted for 20 min. The remaining monomer pre-emulsion was then added dropwise over a period of 4 h. After the addition was completed, the mixture was kept at 80° C. for 1 h. The mixture was cooled to below 45° C., a pH regulator was added to adjust the pH value of the emulsion to 7 to 8, and finally 1 g of an acetylene glycol wetting agent and 1 g of an organosilicon defoaming agent were added. The mixture was stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive having a concentration of 40.5% and a viscosity of 180 mPa·s.

[0074] Preparation of label material: coating silicon on the base material, controlling the coating amount to 0.35g / ㎡, coating the above-mentioned water-based polymer pressure-sensitive adhesive on the surface material, and after drying, compounding the base material and the surface material into a label material; die-cutting the label material into multiple finished labels with set sizes. Among them, the surface material is prepared by the following method: (by weight) 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant are mixed and melted, and then cast into sheets and then biaxially stretched 4.4 times, and then rapidly cooled and shaped at 30°C. The lubricant is kaolin; the base material is polyethylene terephthalate melted, cast into sheets and then biaxially stretched 2 times, and then heat-set at 220°C.

[0075] Example 4

[0076] This embodiment provides a water-based polymer pressure-sensitive adhesive, including the following raw materials: 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 ethoxy methacrylate, and 50 g of isobornyl methacrylate.

[0077] The preparation method of the water-soluble polyester is as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of sodium bis(hydroxyethyl)isophthalate-5-sulfonate and 12 g of 4-hydroxybutyl acrylate are put into a reaction kettle, the temperature is raised to 125° C., 2 g of initiator antimony ethylene glycol is added for esterification reaction, and after reacting for 3 hours, the temperature is raised to 215° C. for polycondensation reaction, and after reacting for 5 hours, the water-soluble polyester is obtained by discharging the material, and the viscosity is 7100 mPa·s.

[0078] In this embodiment, the specific preparation method of the water-based 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 ethoxy methacrylate, 50 g of isobornyl methacrylate, 620 g of deionized water and 2 g of ammonium persulfate were mixed, and stirred and emulsified to obtain a monomer pre-emulsion having a solid content of 44%;

[0080] (2) 60 g of deionized water was heated to 80° C., 73.5 g of the monomer pre-emulsion prepared in step (1) was added, and the mixture was reacted for 20 min. The remaining monomer pre-emulsion was then added dropwise over a period of 4 h. After the addition was completed, the mixture was kept at 80° C. for 1 h. The mixture was cooled to below 45° C., a pH regulator was added to adjust the pH value of the emulsion to 7 to 8, and finally 1 g of an acetylene glycol wetting agent and 1 g of an organosilicon defoaming agent were added. The mixture was stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive having a concentration of 41.8% and a viscosity of 190 mPa·s.

[0081] Preparation of label material: coating silicon on the base material, controlling the coating amount to 0.35g / ㎡, coating the above-mentioned water-based polymer pressure-sensitive adhesive on the surface material, and after drying, compounding the base material and the surface material into a label material; die-cutting the label material into multiple finished labels with set sizes. Among them, the surface material is prepared by the following method: (by weight) 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant are mixed and melted, and then cast into sheets and then biaxially stretched 4.4 times, and then rapidly cooled and shaped at 30°C. The lubricant is silicon dioxide; the base material is polyethylene terephthalate melted, and then cast into sheets and then biaxially stretched 2 times, and then heat-set at 220°C.

[0082] Comparative Example 1

[0083] This comparative example provides a water-based polymer pressure-sensitive adhesive, comprising the following raw materials: 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.

[0084] The preparation method of the water-soluble polyester is as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of sodium bis(hydroxyethyl)isophthalate-5-sulfonate and 15 g of 4-hydroxybutyl acrylate are put into a reaction kettle, the temperature is raised to 125° C., 2 g of initiator antimony ethylene glycol is added for esterification reaction, and after reacting for 3 hours, the temperature is raised to 215° C. for polycondensation reaction, and after reacting for 5 hours, the water-soluble polyester is obtained by discharging the material with a viscosity of 8500 mPa·s.

[0085] The specific preparation method of the water-based polymer pressure-sensitive adhesive comprises the following steps:

[0086] (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 stirred and emulsified to obtain a monomer pre-emulsion having a solid content of 46.8%;

[0087] (2) 90 g of deionized water was heated to 80° C., 73.5 g of the monomer pre-emulsion prepared in step (1) was added, and the mixture was reacted for 20 min. The remaining monomer pre-emulsion was then added dropwise over a period of 4 h. After the addition was completed, the mixture was kept at 80° C. for 1 h. The mixture was cooled to below 45° C., a pH regulator was added to adjust the pH value of the emulsion to 7 to 8, and finally 1 g of an acetylene glycol wetting agent and 1 g of an organosilicon defoaming agent were added. The mixture was stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive having a concentration of 42.7% and a viscosity of 210 mPa·s.

[0088] Preparation of label material: coating silicon on the base material, controlling the coating amount to 0.35g / ㎡, coating the above-mentioned water-based polymer pressure-sensitive adhesive on the surface material, and after drying, compounding the base material and the surface material into a label material; die-cutting the label material into multiple finished labels with set sizes. Among them, the surface material is prepared by the following method: (by weight) 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant are mixed and melted, and then cast into sheets and then biaxially stretched by 4.4 times, and then rapidly cooled and shaped at 30°C. Lubricant aluminum oxide; the base material is polyethylene terephthalate melted, cast into sheets and then biaxially stretched by 2 times, and then heat-set at 220°C.

[0089] Comparative Example 2

[0090] This comparative example provides a water-based polymer pressure-sensitive adhesive, comprising the following raw materials: 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 ethoxy methacrylate, and 50 g of isobornyl methacrylate.

[0091] Among them, the preparation method of the water-soluble polyester is as follows: 75g of terephthalic acid, 20g of ethylene glycol, and 3g of sodium bis(hydroxyethyl)isophthalate-5-sulfonate are put into a reactor, the temperature is raised to 125°C, and 2g of initiator ethylene glycol antimony is added for esterification reaction. After reacting for 3 hours, the temperature is raised to 215°C for condensation reaction. After reacting for 5 hours, the water-soluble polyester is obtained by discharging the material with a viscosity of 8200mPa·s.

[0092] The specific preparation method of the water-based polymer pressure-sensitive adhesive comprises the following steps:

[0093] (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 ethoxy methacrylate, 50 g of isobornyl methacrylate, 600 g of deionized water and 2 g of ammonium persulfate were mixed, and stirred and emulsified to obtain a monomer pre-emulsion having a solid content of 47%;

[0094] (2) 100 g of deionized water was heated to 80° C., 73.5 g of the monomer pre-emulsion prepared in step (1) was added, and the mixture was reacted for 20 min. The remaining monomer pre-emulsion was then added dropwise over a period of 4 h. After the addition was completed, the mixture was kept at 80° C. for 1 h. The mixture was cooled to 65° C. and kept for 1 h. The mixture was cooled to below 45° C., a pH regulator was added to adjust the pH value of the emulsion to 7 to 8, and finally 1 g of an acetylene glycol wetting agent and 1 g of an organosilicon defoaming agent were added. The mixture was stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive having a concentration of 43.5% and a viscosity of 240 mPa·s.

[0095] Preparation of label material: coating silicon on the base material, controlling the coating amount to 0.35g / ㎡, coating the above-mentioned water-based polymer pressure-sensitive adhesive on the surface material, and after drying, compounding the base material and the surface material into a label material; die-cutting the label material into multiple finished labels with set sizes. Among them, the surface material is prepared by the following method: (by weight) 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant are mixed and melted, and then cast into sheets and then biaxially stretched 4.4 times, and then rapidly cooled and shaped at 30°C. The lubricant is kaolin; the base material is polyethylene terephthalate melted, cast into sheets and then biaxially stretched 2 times, and then heat-set at 220°C.

[0096] Comparative Example 3

[0097] This comparative example provides a water-based polymer pressure-sensitive adhesive, comprising the following raw materials: 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 urea (produced by Guangzhou Sanwang Chemical Materials Co., Ltd., model SW910), and 50 g of isobornyl methacrylate.

[0098] The preparation method of the water-soluble polyester is as follows: 75 g of terephthalic acid, 20 g of ethylene glycol, 3 g of sodium bis(hydroxyethyl)isophthalate-5-sulfonate and 14 g of 4-hydroxybutyl acrylate are put into a reaction kettle, the temperature is raised to 125° C., 2 g of initiator antimony ethylene glycol is added for esterification reaction, and after reacting for 3 hours, the temperature is raised to 215° C. for polycondensation reaction, and after reacting for 5 hours, the water-soluble polyester is obtained by discharging the material, and the viscosity is 7400 mPa·s.

[0099] The specific preparation method of the water-based polymer pressure-sensitive adhesive comprises the following steps:

[0100] (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 urea, 50 g of isobornyl methacrylate, 680 g of deionized water and 2 g of ammonium persulfate were mixed, and stirred and emulsified to obtain a monomer pre-emulsion having a solid content of 44.2%;

[0101] (2) 80 g of deionized water was heated to 80° C., 73.5 g of the monomer pre-emulsion prepared in step (1) was added, and the mixture was reacted for 20 min. The remaining monomer pre-emulsion was then added dropwise over a period of 4 h. After the addition was completed, the mixture was kept at 80° C. for 1 h. The mixture was cooled to 65° C. and reacted for 1 h. The mixture was cooled to below 45° C., a pH regulator was added to adjust the pH of the emulsion to 7 to 8, and finally 1 g of an acetylene glycol wetting agent and 1 g of an organosilicon defoaming agent were added. The mixture was stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive having a concentration of 41.5% and a viscosity of 170 mPa·s.

[0102] Preparation of label material: coating silicon on the base material, controlling the coating amount to 0.35g / ㎡, coating the above-mentioned water-based polymer pressure-sensitive adhesive on the surface material, and after drying, compounding the base material and the surface material into a label material; die-cutting the label material into multiple finished labels with set sizes. Among them, the surface material is prepared by the following method: (by weight) 50 parts of amorphous transparent or white PETG, 30 parts of PET, 19.5 parts of polycarbonate, and 0.5 parts of lubricant are mixed and melted, and then cast into sheets and then biaxially stretched 4.4 times, and then rapidly cooled and shaped at 30°C. The lubricant is silicon dioxide; the base material is polyethylene terephthalate melted, and then cast into sheets and then biaxially stretched 2 times, and then heat-set at 220°C.

[0103] Application Experiment Example

[0104] The label materials prepared in Examples 1-4 and the label materials prepared in Comparative Examples 1-3 were tested for initial adhesion, sustained adhesion, and 180° peel strength, respectively, and the adhesion between two adjacent second label materials after die-cutting was observed. The test results are shown in Table 1.

[0105] Test method: Initial tack is measured according to the "Test method for initial tack of pressure-sensitive adhesive tapes (ring method)" GB / T 31125-2014; persistent tack is measured according to the "Test method for persistent tack of adhesive tapes" GBT 4851-2014; 180° peel strength is measured according to the "Test method for peel strength of adhesive tapes" GB / T2792-2014.

[0106] Table 1 Performance test results

[0107]

[0108] As can be seen from the above table, in Comparative Examples 1 and 3, when no urea monomer is added to the water-based polymer pressure-sensitive adhesive or different types of urea monomers are replaced, the water-based polymer pressure-sensitive adhesive has low crosslinking strength and low cohesive force, resulting in high initial adhesion, low sustained adhesion and peeling force of the label, and the surface material of the label will adhere to the base material during the labeling process. In Comparative Example 2, no 4-hydroxybutyl acrylate is added to the water-based polymer pressure-sensitive adhesive, resulting in poor wettability of the water-based polymer pressure-sensitive adhesive to the surface material and low adhesion. As a result, the label has low sustained adhesion and peeling force, and the surface material of the label will adhere to the base material during the labeling process. The label materials prepared in Examples 1-4 have high compatibility with the surface material, good wettability, adhesion and bonding of the surface material, high cross-linking strength and high cohesion, which can make the label obtain good initial adhesion, sustained adhesion and peeling strength, so that the surface material of the label will not adhere to the base material during the labeling process, and the labeling can be completed quickly. After the labeling, no residual glue will be left on the base paper, avoiding affecting the recycling of the base paper. At the same time, by increasing the internal cross-linking strength, the water-based polymer pressure-sensitive adhesive improves the cohesive strength, thereby improving the hardness of the pressure-sensitive adhesive and reducing its rebound fluidity, so that there will be no adhesion of glue threads during the die-cutting process, avoiding rebound after die-cutting, and flowing to the incision position to produce gluing, avoiding the situation where two adjacent label products after die-cutting are adhered to each other. Traditional labels must have a waste discharge area due to the problem of adhesion between two adjacent labels after die-cutting, resulting in a large amount of substrate and glue waste. However, when the water-based polymer pressure-sensitive adhesive provided by the present invention is applied to labels, it is not easy for two adjacent finished labels to stick together during the die-cutting process, so that there is no need to set a waste discharge area when the labels are die-cut, achieving zero label waste.

[0109] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A water-based polymer pressure-sensitive adhesive, characterized in that: It is polymerized from the following raw materials in parts by weight: 4-6 parts of water-soluble polyester, 16-18 parts of C1-C4 alkyl ester of methacrylate, 16-18 parts of C4-C8 alkyl ester of acrylic acid, and (meth) urea acrylate CHR 1 CH-COOR 2 2-8 parts, 4-5 parts of cycloalkyl methacrylate, wherein R 1 is H or methyl, R 2 is a linear or cyclic ureido group containing 3 to 5 carbon atoms, and the cycloalkyl ester of methacrylic acid is C5-C 20 Cycloalkyl esters; The water-soluble polyester is obtained by polymerizing the following raw materials in parts by weight: 1-5 parts of sulfonate for polyester modification, hydroxyalkyl (meth) acrylic acid ester CHR 3 CH-COOR 4 OH 10-15 parts, terephthalic acid 60-80 parts, ethylene glycol 20-30 parts, of which R 3 is H or methyl, R 4 It is a straight or branched chain alkylene group containing 2 to 5 carbon atoms.

2. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The ureido (meth)acrylate CHR 1 CH-COOR 2 It is ethylene urea ethoxy methacrylate.

3. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The hydroxyalkyl (meth)acrylate CHR 3 CH-COOR 4 OH is 2-hydroxyethyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate or 4-hydroxybutyl acrylate.

4. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The hydroxyalkyl (meth)acrylate CHR 3 CH-COOR 4 OH is 4-hydroxybutyl acrylate.

5. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The sulfonate used for polyester modification is sodium bis(hydroxyethyl)isophthalate-5-sulfonate.

6. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The cycloalkyl ester of methacrylic acid is a C5-C 10 Cycloalkyl esters.

7. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The viscosity of the water-soluble polyester is 5000-10000 mPa·s.

8. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The preparation method of the water-based polymer pressure-sensitive adhesive is as follows: (1) mixing a water-soluble polyester with a C1-C4 alkyl methacrylate, a C4-C8 alkyl acrylate, a ureido acrylate, a cycloalkyl methacrylate and a first portion of deionized water, and stirring and emulsifying to obtain a monomer pre-emulsion having a solid content of 30% to 50%; (2) 50-100 parts by weight of the second portion of deionized water is heated and then added to 10%-20% of the monomer pre-emulsion obtained in step (1) to carry out a free radical polymerization reaction, and then the remaining pre-emulsion is added dropwise to carry out a free radical polymerization reaction. The viscosity of the obtained product is 100-500 mPa·s.

9. The water-based polymer pressure-sensitive adhesive according to claim 1, characterized in that: The preparation method of the water-based polymer pressure-sensitive adhesive is: (1) mixing a water-soluble polyester with C1-C4 alkyl methacrylate, C4-C8 alkyl acrylate, ureido acrylate, cycloalkyl methacrylate, the first portion of deionized water, and a free radical initiator, and stirring and emulsifying to obtain a monomer pre-emulsion, wherein the weight of the initiator is 0.3% to 0.8% of the total weight of the water-soluble polyester, C1-C4 alkyl methacrylate, C4-C8 alkyl acrylate, ureido acrylate, and cycloalkyl methacrylate; (2) The second portion of deionized water is heated to 78-82° C., 10%-20% of the monomer pre-emulsion obtained in step (1) is added, and the reaction is continued for 15-25 minutes. The remaining monomer pre-emulsion is then added dropwise over a period of 2-5 hours. After the addition is completed, the mixture is kept at 80-85° C. for 1-2 hours. The mixture is cooled to below 45° C., the pH value is adjusted to 7-8, and finally a wetting agent and a defoaming agent are added. The mixture is stirred evenly and filtered to obtain a water-based polymer pressure-sensitive adhesive.

10. A label material comprising the water-based polymer pressure-sensitive adhesive according to any one of claims 1 to 9, characterized in that: It includes a polyester-based surface material and a water-based polymer pressure-sensitive adhesive that are bonded to each other.

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