Environment-friendly high-performance water-based acrylate pressure-sensitive adhesive and preparation method thereof

Abstract

This invention provides an environmentally friendly, high-performance waterborne acrylic pressure-sensitive adhesive and its preparation method. The raw materials, by weight, include: 75-105 parts monomer, 1-5 parts functional monomer, 0.3-0.8 parts initiator, 0.05-0.2 parts buffer, 0.01-0.1 parts molecular weight regulator, 0.3-3 parts emulsifier, 0.05-0.5 parts defoamer, 0.05-0.2 parts pH adjuster, and 80-100 parts deionized water. The prepared pressure-sensitive adhesive is nonylphenol-free and meets RoHS and REACH standards. It exhibits high bonding strength and transparency, and can be used to prepare various transparent, printed, and colored BOPP packaging tapes, various double-sided tapes, and various labels.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of C09J7 / 10, and particularly relates to an environment-friendly high-performance water-based acrylic ester pressure-sensitive adhesive and a preparation method thereof. BACKGROUND

[0002] Pressure-sensitive adhesive is divided into rubber-based pressure-sensitive adhesive, polyacrylate-based pressure-sensitive adhesive, polyvinyl ether resin-based, polyurethane resin-based, polyisobutylene-based emulsion pressure-sensitive adhesive, and emulsion pressure-sensitive adhesive occupies an absolute dominant position, which is a major feature of China's pressure-sensitive adhesive industry. Emulsion pressure-sensitive adhesive, especially acrylic emulsion pressure-sensitive adhesive, has special importance in China.

[0003] CN111286283A discloses a preparation method of an acrylic pressure-sensitive adhesive tape for bonding low surface energy materials, and the preparation raw materials include: perfluoro surfactant, water-soluble acrylic ester glue, and curing agent. The water-soluble acrylic ester glue can be modified according to different application occasions and different requirements for adhesion, so as to reduce the overall surface energy of the glue. However, the overall performance of the adhesive tape prepared by the method is low, and the bonding performance of the adhesive tape for PP and PE and other low surface energy materials has not been tested. In addition, the water-based acrylic coating has high requirements for the selection and matching of release materials, and the applicability of the adhesive tape is low.

[0004] CN110819273B discloses a thin-coated high-adhesion pressure-sensitive adhesive, and the preparation raw materials include: acrylic ester resin paste, curing agent, and tackifying resin. The pressure-sensitive adhesive has excellent initial adhesion and excellent peeling force, and the glue has good flowability. The prepared pressure-sensitive adhesive tape has a thin thickness and high bonding strength for nanocrystals. However, the glue has low transparency, and the viscosity still needs to be further improved. SUMMARY

[0005] In view of the above problems, the present application discloses an environment-friendly high-performance water-based acrylic ester pressure-sensitive adhesive. The preparation raw materials include, by mass fraction: 75-105 parts of monomers, 1-5 parts of functional monomers, 0.3-0.8 parts of initiators, 0.05-0.2 parts of buffers, 0.01-0.1 parts of molecular weight regulators, 0.3-3 parts of emulsifiers, 0.05-0.5 parts of defoaming agents, 0.05-0.2 parts of pH regulators, and 80-100 parts of deionized water.

[0006] In an embodiment, the monomers are acrylic acid monomers and / or acrylic ester monomers.

[0007] Preferably, the monomers are acrylic ester monomers.

[0008] In an embodiment, the acrylic ester monomers are selected from one or more of acrylic ester soft monomers, acrylic acid hard monomers, and acrylic ester polar monomers.

[0009] Preferably, the acrylate monomer is a combination of acrylate soft monomer and acrylate hard monomer, with a mass ratio of (70-90):(5-15).

[0010] The acrylate soft monomer includes but is not limited to butyl acrylate, isooctyl acrylate, dodecyl acrylate, isobutyl acrylate, ethyl acrylate, n-propyl acrylate, n-hexyl acrylate.

[0011] Preferably, the acrylate soft monomer is dodecyl acrylate, n-propyl acrylate, n-hexyl acrylate, with a mass ratio of 1:(0.3-1):(0.3-1).

[0012] Further preferably, the acrylate soft monomer is dodecyl acrylate, n-propyl acrylate, n-hexyl acrylate, with a mass ratio of 1:0.5:0.3.

[0013] The acrylate hard monomer includes but is not limited to methyl methacrylate, ethyl acetate, methyl acrylate, tert-butyl acrylate, ethyl methacrylate, butyl methacrylate, tert-butyl methacrylate, vinyl versatate, isopropyl methacrylate.

[0014] Preferably, the acrylate hard monomer is ethyl methacrylate.

[0015] In an embodiment, the functional monomer is selected from one or more of a hydroxyl-containing functional monomer, an amino-containing functional monomer, and a carboxyl-containing functional monomer.

[0016] Preferably, the functional monomer is an amino-containing functional monomer, including but not limited to acrylamide, methacrylamide, N-methylol methacrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide.

[0017] Further preferably, the functional monomer is N-methylol methacrylamide and methacrylamide, with a mass ratio of 1:(3-10).

[0018] In an embodiment, the initiator is a peroxide compound initiator and / or an oxidation-reduction initiator.

[0019] Preferably, the initiator is a peroxide compound initiator.

[0020] The peroxide compound initiator includes but is not limited to sodium persulfate, potassium persulfate, ammonium persulfate, tert-butyl hydroperoxide.

[0021] Preferably, the initiator is potassium persulfate.

[0022] In an embodiment, the buffer is a strong acid-weak base salt and / or a weak acid-strong base salt.

[0023] Preferably, the buffering agent is a salt of a weak acid and a strong base.

[0024] Further preferably, the buffering agent is sodium bicarbonate.

[0025] In one embodiment, the molecular weight regulator is selected from one or more of aliphatic mercaptans, mercapto-containing organic compounds, polyphenols, and nitroso compounds.

[0026] Preferably, the molecular weight regulator is a combination of aliphatic mercaptans and mercapto-containing organic compounds in a mass ratio of 1 : (2-3).

[0027] Further preferably, the aliphatic mercaptans are n-dodecyl mercaptan and the mercapto-containing organic compounds are 3-mercaptopropionic acid butyl ester.

[0028] In one embodiment, the emulsifier is selected from one or more of anionic emulsifiers, non-ionic emulsifiers, and reactive emulsifiers.

[0029] Preferably, the emulsifier is a combination of non-ionic emulsifiers and reactive emulsifiers in a mass ratio of (7-20) : 1.

[0030] In one embodiment, the non-ionic emulsifier is selected from one or more of fatty acid soaps, alkyl sulfate salts, alkyl benzene sulfonate salts, phosphate salts, and alcohol ethers.

[0031] Preferably, the non-ionic emulsifier is an alcohol ether.

[0032] Further preferably, the alcohol ether is a fatty alcohol ether phosphate ester.

[0033] In one embodiment, the reactive emulsifier is selected from one or more of methacrylic acid type, acrylamide type, vinyl type, and maleic anhydride type.

[0034] Preferably, the reactive emulsifier is a vinyl type, including but not limited to vinyl sulfonate salts, vinyl polyether ammonium sulfate salts, and vinyl alcohol ether phosphate esters.

[0035] Further preferably, the reactive emulsifier is a vinyl alcohol ether phosphate ester.

[0036] The polar groups of the functional monomers, such as hydroxyl, amino, carboxyl, etc., can provide crosslinking points, so that intramolecular self-crosslinking reaction occurs, a network structure is formed, the hardness of the coating film is increased, the tensile strength of the coating film is improved, the polarity of the whole polymer resin is improved, and the initial adhesion effect is improved. However, the functional monomers, such as the N-hydroxymethyl acrylamide added in the present application, also increase the hydrophilicity, which causes the water resistance and water bonding resistance of the pressure-sensitive adhesive to decrease. The types of the hydrophilic groups of the anionic surfactants are limited, but the hydrophobic groups are rich in structure, the anionic surfactant is the fatty alcohol ether phosphate, and the types of the soft monomers and the hard monomers are controlled, so that the water resistance is improved. The reason is that the soft monomers are selected to be dodecyl acrylate, n-propyl acrylate and n-hexyl acrylate, and the hard monomer is ethyl methacrylate, the monomer structure is rich, the crosslinking structure of the system is more complex, the compatibility and dispersibility are good under the action of the fatty alcohol ether phosphate, the wetting performance is excellent, the water resistance is improved, and the bonding resistance is further improved.

[0037] In an embodiment, the defoaming agent is selected from any one of non-silicon type, polyether type, organic silicon type and polyether modified organic silicon type.

[0038] Preferably, the defoaming agent is of polyether type.

[0039] In an embodiment, the pH regulator is an inorganic alkali solution and / or an organic alkali solution.

[0040] Preferably, the pH regulator is an organic alkali solution.

[0041] Further preferably, the pH regulator is diethanolamine.

[0042] In an embodiment, the environmentally friendly high-performance water-based acrylic pressure-sensitive adhesive further comprises, by mass fraction, 0.1-0.5 parts of a thickening agent and 0.05-0.3 parts of a preservative.

[0043] Preferably, the thickening agent is selected from one or more of alkali swelling ASE-60, TT935, polyurethane UH-420 and 852.

[0044] Preferably, the preservative is selected from one or more of sorbic acid, potassium sorbate, benzoic acid, sodium benzoate and calcium propionate.

[0045] Another aspect of the present application discloses a preparation method of the environmentally friendly high-performance water-based acrylic pressure-sensitive adhesive, comprising the following steps: (1) monomer pre-emulsification; (2) polymerization of seed emulsion; and (3) polymerization of main body emulsion.

[0046] Specifically,

[0047] (1) monomer pre-emulsification: water, emulsifier is put into the emulsification tank, stirring is started, then monomer, functional monomer is added, emulsification is continued for 30-60 min, uniform and stable emulsified monomer is obtained;

[0048] (2) polymerization of seed emulsion: pH regulator, molecular weight regulator is added in the reaction kettle, temperature is raised to 80-85℃, 40% initiator and 10% of the total amount of emulsified monomer prepared in step (1) is added, reaction is carried out for 15-30 min, and then it is kept for 20-40 min to prepare the seed emulsion;

[0049] (3) polymerization of main emulsion: in the reaction kettle described in step (2), all the remaining emulsified monomers and the remaining initiator are continuously added dropwise, and the temperature is controlled at 83-85℃. After the dropwise addition is completed, it is kept for 30-60 min. When the temperature is lowered to 60-70℃, residual monomer treatment agent is added, and after keeping for 20-35 min, defoaming agent, thickening agent and preservative are gradually added and stirred uniformly to obtain the product.

[0050] Beneficial effects

[0051] 1. The polar groups such as hydroxyl, amino and carboxyl of the functional monomer can provide crosslinking points, so that intramolecular self-crosslinking reaction occurs, a network structure is formed, the hardness of the coating film is increased, and the tensile strength of the coating film is also improved.

[0052] 2. The addition of anionic surfactant and the control of the types of soft monomers and hard monomers not only improve the water resistance, but also further improve the adhesion.

[0053] 3. The emulsifier is a combination of nonionic emulsifier and reactive emulsifier, and the mass ratio is (7-20):1. The agglomeration can be reduced, and the adhesion and stability are improved.

[0054] 4. The prepared pressure-sensitive adhesive does not contain nonyl phenol, and meets the rohs and reach standards.

[0055] 5. The adhesive bonding strength is large, the transparency is high, and it can be applied to the preparation of various transparent, printed, colored BOPP packaging adhesive tapes, various double-sided adhesive tapes and various labels. DETAILED DESCRIPTION

[0056] Example 1

[0057] The example 1 discloses an environmentally friendly high-performance water-based acrylic pressure-sensitive adhesive. The preparation raw materials are 75 parts of monomer, 2 parts of functional monomer, 0.4 parts of initiator, 0.1 parts of buffer, 0.02 parts of molecular weight regulator, 0.3 parts of emulsifier, 0.05 parts of defoaming agent, 0.05 parts of pH regulator, 80 parts of deionized water and 0.1 parts of thickening agent, 0.05 parts of preservative.

[0058] The monomer is a combination of acrylate soft monomer and acrylic hard monomer, with a mass ratio of 70:5.

[0059] The acrylate soft monomer is dodecyl acrylate, n-propyl acrylate, and n-hexyl acrylate, with a mass ratio of 1:1:1.

[0060] The acrylic hard monomer is ethyl methacrylate.

[0061] The functional monomer is N-hydroxymethyl acrylamide and methacrylamide, with a mass ratio of 1:3.

[0062] The initiator is potassium persulfate.

[0063] The buffer is sodium bicarbonate.

[0064] The molecular weight regulator is n-dodecyl mercaptan and 3-mercapto butyl propionate, with a mass ratio of 1:2.

[0065] The emulsifier is a combination of fatty alcohol ether phosphate and vinyl alcohol ether phosphate, with a mass ratio of 7:1.

[0066] The defoaming agent is polyether type, purchased from Guangzhou Kanglunxi Chemical Technology Co., Ltd., model KX-306.

[0067] The pH regulator is diethanolamine.

[0068] The thickening agent is polyurethane UH-420, purchased from Shenzhen Xiangrun New Material Co., Ltd., brand: Aidi Ke, model UH-420.

[0069] The preservative is selected from sorbic acid.

[0070] The other aspect of the present embodiment 1 discloses a preparation method of the environmentally friendly high-performance water-based acrylate pressure-sensitive adhesive, with the following steps:

[0071] (1) Monomer pre-emulsification: Put water and emulsifier into the emulsification tank, start stirring, then add monomer and functional monomer, and continue emulsification for 45 min to obtain uniform and stable emulsified monomer;

[0072] (2) Polymerization of seed emulsion: Add pH regulator and molecular weight regulator to the reaction kettle, heat to 80℃, add 40% initiator and 10% of the total amount of emulsified monomer prepared in step (1), react for 20 min, and then keep warm for 30 min to prepare the seed emulsion;

[0073] (3) Polymerization of the main body emulsion: in the reactor described in step (2), continue to add all the remaining emulsified monomers and the remaining initiator, control the temperature at 85℃, and keep for 45 min after the addition; when the temperature is lowered to 65℃, add the residual monomer treatment agent, keep for 30 min, then gradually add the defoaming agent, thickening agent and preservative, and stir uniformly to obtain the product.

[0074] Example 2

[0075] The present embodiment 2 discloses an environmentally friendly high-performance water-based acrylic pressure-sensitive adhesive. The preparation raw materials are 105 parts of monomers, 5 parts of functional monomers, 0.8 parts of initiator, 2 parts of buffer, 0.1 parts of molecular weight regulator, 3 parts of emulsifier, 0.5 parts of defoaming agent, 0.2 parts of pH regulator, 100 parts of deionized water, 0.3 parts of thickening agent, and 0.5 parts of preservative.

[0076] The monomers are a combination of acrylic ester soft monomers and acrylic ester hard monomers, with a mass ratio of 90:15.

[0077] The acrylic ester soft monomers are dodecyl acrylate, n-propyl acrylate and n-hexyl acrylate, with a mass ratio of 1:0.3:0.3.

[0078] The acrylic ester hard monomers are ethyl methacrylate.

[0079] The functional monomers are N-hydroxymethyl acrylamide and methacrylamide, with a mass ratio of 1:10.

[0080] The initiator is potassium persulfate.

[0081] The buffer is sodium bicarbonate.

[0082] The molecular weight regulator is n-dodecyl mercaptan and 3-mercapto butyl propionate, with a mass ratio of 1:3.

[0083] The emulsifier is a combination of fatty alcohol ether phosphate and vinyl alcohol ether phosphate, with a mass ratio of 20:1.

[0084] The defoaming agent is polyether type, which is purchased from Guangzhou Kanglunxi Chemical Technology Co., Ltd., and the model is KX-306.

[0085] The pH regulator is diethanolamine.

[0086] The thickening agent is polyurethane UH-420, which is purchased from Shenzhen Xiangrun New Material Co., Ltd., the brand is Aidi Ke, and the model is UH-420.

[0087] The preservative is selected from sorbic acid.

[0088] The preparation method is the same as that of embodiment 1.

[0089] Example 3

[0090] The embodiment 3 discloses an environmentally friendly high-performance water-based acrylic pressure-sensitive adhesive. The preparation raw materials are 90 parts of monomer, 3 parts of functional monomer, 0.5 parts of initiator, 0.1 parts of buffer, 0.08 parts of molecular weight regulator, 1 parts of emulsifier, 0.2 parts of defoaming agent, 0.1 parts of pH regulator, 90 parts of deionized water, 0.08 parts of thickening agent and 0.07 parts of preservative.

[0091] The monomer is a combination of acrylic ester soft monomer and acrylic hard monomer, and the mass ratio is 80:10.

[0092] The acrylic ester soft monomer is dodecyl acrylate, n-propyl acrylate and n-hexyl acrylate, and the mass ratio is 1:0.5:0.3.

[0093] The acrylic hard monomer is ethyl methacrylate.

[0094] The functional monomer is N-hydroxymethyl acrylamide and methacrylamide, and the mass ratio is 1:5.

[0095] The initiator is potassium persulfate.

[0096] The buffer is sodium bicarbonate.

[0097] The molecular weight regulator is n-dodecyl mercaptan and 3-mercapto butyl propionate, and the mass ratio is 1:2.5.

[0098] The emulsifier is a combination of fatty alcohol ether phosphate and vinyl alcohol ether phosphate, and the mass ratio is 10:1.

[0099] The defoaming agent is polyether type, which is purchased from Guangzhou Kanglunxi Chemical Technology Co., Ltd., and the model is KX-306.

[0100] The pH regulator is diethanolamine.

[0101] The thickening agent is polyurethane UH-420, which is purchased from Shenzhen Xiangrun New Material Co., Ltd., the brand is Aidi Ke, and the model is UH-420.

[0102] The preservative is selected from sorbic acid.

[0103] The preparation method is the same as that of embodiment 1.

[0104] Example 4

[0105] The embodiment is different from embodiment 3 in that the acrylic ester soft monomer is dodecyl acrylate, n-propyl acrylate and n-hexyl acrylate, and the mass ratio is 0.5:1:2.

[0106] Example 5

[0107] The difference between this embodiment and embodiment 3 is that the acrylate soft monomer is dodecyl acrylate.

[0108] Example 6

[0109] The difference between this embodiment and embodiment 3 is that the functional monomer is acrylic acid and hydroxyethyl acrylate, and the mass ratio is 1:1.

[0110] Example 7

[0111] The difference between this embodiment and embodiment 3 is that the emulsifier is a vinyl alcohol ether phosphate ester.

[0112] Performance tests

[0113] The pressure-sensitive adhesive was coated on 25 μm BOPP with a coating wire bar, placed in a 90°C oven, and after 5 min, the solvent was volatilized and dried, the dry adhesive thickness was controlled to be 25 μm, then a release paper was overlaid to obtain a single-sided adhesive tape.

[0114] 1. Peeling force test: according to GB / T 2792 Adhesive Tape Peeling Strength Test Method.

[0115] 2. Initial adhesion test: GB / T 4852 Adhesive Tape Initial Adhesion Test Method.

[0116] 3. Holding adhesion: GB / T 4851 Adhesive Tape Holding Adhesion Test Method.

[0117]

[0118]

[0119] Embodiments 4 and 5 can verify the influence of the component of the acrylate soft monomer on the adhesive performance, and embodiments 6 and 7 can verify the influence of the functional monomer containing amino groups and anionic surfactants on the adhesive performance.

Claims

1. An environmentally friendly high performance waterborne acrylate pressure sensitive adhesive, characterized in that, The preparation raw materials include, by mass fraction: 75-105 parts of monomer, 1-5 parts of functional monomer, 0.3-0.8 parts of initiator, 0.05-0.2 parts of buffer, 0.01-0.1 parts of molecular weight regulator, 0.3-3 parts of emulsifier, 0.05-0.5 parts of defoaming agent, 0.05-0.2 parts of pH regulator, 80-100 parts of deionized water; The emulsifier is a combination of non-ionic emulsifier and reactive emulsifier, the mass ratio is (7-20):1, the non-ionic emulsifier is fatty alcohol ether phosphate, and the reactive emulsifier is vinyl alcohol ether phosphate; The monomer is a combination of acrylate soft monomer and acrylic hard monomer, the acrylate soft monomer is a specific ternary combination of lauryl acrylate, n-propyl acrylate and n-hexyl acrylate, and the mass ratio is 1:(0.3-1):(0.3-1). The functional monomer is N-hydroxymethyl acrylamide and methacrylamide, and the mass ratio is 1:(3-10).

2. The aqueous acrylate pressure sensitive adhesive of claim 1, wherein, The monomer is a combination of acrylate soft monomer and acrylic hard monomer, and the mass ratio is (70-90):(5-15).

3. The aqueous acrylate pressure sensitive adhesive of claim 1, wherein, The initiator is a peroxide initiator and / or an oxidation-reduction initiator.

4. The aqueous acrylate pressure sensitive adhesive according to any one of claims 1 to 3, characterized in that, The preparation raw materials of the environmentally friendly high-performance water-based acrylate pressure-sensitive adhesive further include, by mass fraction: 0.1-0.5 parts of thickening agent, and 0.05-0.3 parts of preservative.

5. A method of preparing the aqueous acrylate pressure sensitive adhesive according to claim 4, characterized in that, The steps include: (1) monomer pre-emulsification; (2) polymerization of seed emulsion; (3) polymerization of main body emulsion.

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