CN117210173A

CN117210173A - Water-based pressure-sensitive adhesive and preparation method and application thereof

Info

Publication number: CN117210173A
Application number: CN202311415353.3A
Authority: CN
Inventors: 王彦彬
Original assignee: Shanghai Baolijia New Material Co ltd
Current assignee: Shanghai Baolijia New Material Co ltd
Priority date: 2023-10-30
Filing date: 2023-10-30
Publication date: 2023-12-12

Abstract

The invention relates to a water-based pressure-sensitive adhesive and a preparation method and application thereof, wherein the preparation method comprises the following steps: preparation of the fluorochemical block oligomer: polymerizing fluorine-containing monomer and super-hydrophobic long-chain acrylic ester monomer to obtain fluorine-containing block oligomer; the obtained fluorine-containing block oligomer participates in emulsion polymerization to prepare the water-based pressure-sensitive adhesive. Compared with the prior art, the aqueous pressure-sensitive adhesive provided by the invention has low surface energy, is suitable for film materials with low surface energy, has excellent wettability and spreadability, avoids the problem of coating shrinkage cavity in short time, and has good laminating property to a substrate.

Description

Water-based pressure-sensitive adhesive and preparation method and application thereof

Technical Field

The invention belongs to the field of pressure-sensitive adhesives, and particularly relates to a water-based pressure-sensitive adhesive, and a preparation method and application thereof.

Background

For the adhesive field, the replacement of the oily adhesive emulsion with the aqueous adhesive emulsion has become the necessary trend of future development. In recent years, more and more aqueous adhesive products are going into the production and life of people, but the aqueous pressure-sensitive adhesive can cause problems of poor wetting, more bubbles, shrinkage cavity and the like on some low-surface-energy film materials, and particularly, the problems are more prominent in the release film coating process, which brings a series of troubles to the production.

In the prior art, various functional auxiliary agents are added on the basis of a master batch to improve the problems, for example, patent CN115124950A discloses a water-based advertisement paste pressure-sensitive adhesive with excellent wettability, and 0.1-1% of auxiliary agents are added into polymer emulsion, wherein the auxiliary agents comprise thickening agents, wetting agents, defoaming agents and the like, and when the adhesive is used for cold mounting film back-coating, shrinkage-hole-free edge shrinkage can be realized within 5 seconds, so that the production transfer coating requirement is met, and the possible oil shrinkage phenomenon in the use process is avoided. However, the mode of adding the auxiliary agent after the production step is increased, the performance of the adhesive is also adversely affected, and meanwhile, the volatile components are easily increased due to the subsequently added multiple auxiliary agents, so that the environment friendliness of the product is adversely affected.

The pressure-sensitive adhesive emulsion is also improved, for example, patent CN114437649A discloses an organic fluorine modified polyacrylate pressure-sensitive adhesive and a preparation method thereof, wherein fluorine-containing materials containing acrylic double bonds are selected to participate in free radical polymerization reaction and are randomly copolymerized with soft monomers, hard monomers and functional monomers to synthesize the acrylic pressure-sensitive adhesive with ultralow surface energy, however, the solvents used in the patent are organic solvents such as toluene, ethyl acetate, n-hexane, acetone and methanol, and the like, and the acrylic pressure-sensitive adhesive is not an environment-friendly water-based pressure-sensitive adhesive.

For the problems of poor wettability, serious shrinkage cavity and poor cohesiveness of film materials (such as release film or release paper transfer coating) pressure-sensitive adhesives with ultralow surface energy, an aqueous pressure-sensitive adhesive with excellent performance cannot be provided.

Disclosure of Invention

The invention aims to solve the problems and provides a water-based pressure-sensitive adhesive, a preparation method and application thereof. The aqueous pressure-sensitive adhesive provided by the invention has ultra-low surface energy, is suitable for film materials with low surface energy, has excellent wettability, avoids the problem of coating shrinkage cavity, and has good adhesion to a substrate.

The fluorine-containing monomer has superhydrophobicity, and the introduction of emulsion polymerization is helpful for reducing the surface energy of emulsion, and is helpful for improving the wettability and avoiding the problem of coating shrinkage cavity when contacting with a material with low surface energy. In the preparation of the aqueous pressure-sensitive adhesive, the fluorine-containing block oligomer is further introduced, and is obtained through the polymerization reaction of the fluorine-containing monomer and the super-hydrophobic long-chain acrylate monomer, so that the fluorine-containing block oligomer can participate in the emulsion polymerization reaction and is grafted on a polymer molecular chain, and the super-hydrophobic long-chain acrylate monomer has a long-chain structure, so that the hydrophobicity of emulsion is further improved, the particle size and the dispersibility of colloidal particles in an emulsion polymerization system are influenced, the growth rate and the aggregation degree of the colloidal particles are controlled, and meanwhile, the hydrophobic long-chain structure can be used as a bridge for linking the fluorine-containing monomer and the main acrylate monomer, so that the grafting efficiency and the copolymerization effect of a product are further improved, and the stability of the emulsion system in and after polymerization is facilitated.

The invention is realized by the following technical scheme:

the preparation method of the aqueous pressure-sensitive adhesive comprises the following steps:

(1) Preparation of the fluorochemical block oligomer: polymerizing fluorine-containing monomer and super-hydrophobic long-chain acrylic ester monomer to obtain fluorine-containing block oligomer;

(2) And (3) enabling the fluorine-containing block oligomer obtained in the step (1) to participate in emulsion polymerization to prepare the water-based pressure-sensitive adhesive.

As a preferable technical scheme of the invention, the timing of adding the fluorine-containing block oligomer in the step (2) into the polymerization system is as follows: when the pre-emulsified liquid is added in an amount of 50-60wt%, the mixture is added until the polymerization process is completed.

The control of the timing of the addition of the fluorine-containing block oligomer during the polymerization is a key step. Early addition, which is detrimental to improvement of hydrophobicity, has limited effect on lowering the surface energy of the emulsion, and early addition of the fluorine-containing block oligomer affects the rate and extent of polymerization; whereas too late addition, emulsion polymerization presents stability problems, the fluorine-containing block oligomers generally have a relatively low surface tension, forming a stable surfactant layer in the emulsion, too late addition results in incomplete or unstable surfactant layer formation in the emulsion, reducing the stability of the emulsion, and too late addition also results in insufficient interaction with other components in the polymerization system, resulting in uneven phase separation of the emulsion or the appearance of agglomerates. Preferably, the addition is best at the mid-polymerization stage, for example, when the amount of pre-emulsified liquid added is 50-60wt%, most preferably 55wt%.

As a preferable technical scheme of the invention, the preparation method of the water-based pressure-sensitive adhesive comprises the following specific steps:

(a) Preparing kettle base solution: weighing water and an emulsifier 1, adding the water and the emulsifier into a reaction kettle, stirring and heating to 84-86 ℃;

(b) Preparing a pre-emulsion: weighing water and an emulsifying agent 2, adding the water and the emulsifying agent into an emulsifying cylinder, stirring, adding a mixed monomer, and uniformly stirring to obtain a pre-emulsion;

(c) Adding 2-5wt% of the pre-emulsion into a reaction kettle, adding an initiator 1, and carrying out polymerization for 5-25 minutes, preferably 8-15 minutes;

(d) Simultaneously dripping the residual pre-emulsion and the initiator 2 into the reaction kettle within 3-4 hours, starting dripping the fluorine-containing block oligomer when the dripping amount of the pre-emulsion reaches 50-60wt% of the total amount, preserving the heat for 30-60 minutes after dripping, and performing aftertreatment to obtain the water-based pressure-sensitive adhesive;

the step (a) and the step (b) are not sequenced.

As a preferable technical scheme of the invention, the dosage of the emulsifier 1 in the kettle bottom liquid is 2-5wt% based on the total weight of all monomers; the water dosage is 18-22 times of that of the emulsifier 1;

the emulsifier 1 consists of a mixture of an anionic emulsifier and a perfluorinated surfactant, wherein the perfluorinated surfactant accounts for 10-15wt% of the anionic emulsifier.

Preferably, the perfluorinated surfactant is selected from perfluorobutyl sulfonyl fluoride and/or perfluorohexyl sulfonamide.

The addition of a small amount of perfluorinated surfactants in the anionic emulsifier is beneficial to reducing the surface energy of the emulsion, plays a role in defoaming and inhibiting foam, is beneficial to the uniformity of a coated adhesive surface, can increase the wettability and spreadability of the pressure-sensitive adhesive on the surface of a low-surface-energy material, and improves the adhesion.

As a preferable technical scheme of the invention, in the pre-emulsion, the dosage of the emulsifier 2 is 3-5wt percent based on the total weight of all monomers; the water is 18-22 times of the emulsifier 2, and the emulsifier 2 comprises an anionic emulsifier and/or a nonionic emulsifier;

the mixed monomer consists of the following components: the hard monomer, the soft monomer and the functional monomer are mixed according to the weight ratio of 1-3:50-55:1-2;

the amount of said fluorochemical block oligomer added is 5 to 20%, preferably 6 to 9%, for example 8% in a particular embodiment, of the total amount of said mixed monomers;

preferably, the hard monomer is selected from one or more of styrene, methyl methacrylate, methacrylic acid, most preferably styrene;

the soft monomer is selected from one or more of isooctyl acrylate, ethyl acrylate and butyl acrylate;

the functional monomer is selected from one or more of acrylic acid, acrylamide, hydroxybutyl acrylate, hydroxypropyl acrylate and hydroxyethyl acrylate; further preferred are mixtures of acrylic acid and hydroxyethyl acrylate;

for example, in a particular embodiment, the mixed monomer consists of: 2.2 parts of styrene, 53 parts of butyl acrylate, 0.75 part of hydroxyethyl acrylate and 0.8 part of acrylic acid.

The anionic emulsifier comprises one or more of alkyl sulfate (such as sodium dodecyl sulfate), alkylbenzene sulfonate (such as sodium dodecyl benzene sulfonate), dioctyl sodium sulfosuccinate (such as Solvin OT-75), fatty alcohol ether sulfate anionic emulsifier and alkyl polyoxyethylene ether sulfate anionic emulsifier;

the nonionic emulsifier comprises fatty alcohol polyoxyethylene ether (AEO 7, AEO-9).

As a preferable technical scheme of the invention, the initiator 1 and the initiator 2 are selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, tert-butyl hydroperoxide, BPO and AIBN;

preferably, the initiator 1 and the initiator 2 adopt ammonium persulfate, and the dosage of the initiator 1 is 0.1-1wt% of the mixed monomer; the amount of the initiator 2 is 0.2-1wt% of the mixed monomer; preferably, ammonium persulfate is added as an aqueous solution;

and/or, the specific steps of the post-treatment comprise: simultaneously dripping an oxidant and a reducing agent, reacting for 20-40min, cooling to below 50 ℃, adding ammonia water to neutralize the pH to 7.0-8.0, and finally filtering and discharging;

the oxidant comprises tert-butyl hydroperoxide, and the amount of the oxidant is 0.1-0.5wt% of the weight of the mixed monomers; the reducing agent comprises a white suspending block, and the dosage of the white suspending block is 0.1-0.3wt% of the weight of the mixed monomer.

As a preferable technical scheme of the invention, the fluorine-containing block oligomer is prepared by aqueous phase copolymerization, and the specific method comprises the following steps: adding water and cardanol emulsifying agent into a reaction kettle, stirring and dispersing uniformly, keeping a stirring state, adding fluorine-containing monomer, super-hydrophobic long-chain acrylic ester monomer and acrylic ester soft monomer, heating to 60-75 ℃, preferably 70-75 ℃, adding initiator, and carrying out polymerization reaction for 2-4 hours, preferably 3-4 hours to obtain the product.

When the super-hydrophobic long-chain acrylic ester monomer is polymerized with the fluorine-containing monomer, the super-hydrophobic long-chain acrylic ester monomer and the fluorine-containing monomer are not easy to dissolve in water due to the hydrophobicity of the super-hydrophobic long-chain acrylic ester monomer and the fluorine-containing monomer, the stability is poor, the crosslinking property is poor, the amount of coagulum in the polymerization process is large, the polymerization is difficult to polymerize, the cardanol emulsifier is adopted, the methylene structure in the cardanol is utilized to enable the emulsion to have high crosslinking property, the characteristic of the cardanol long-carbon chain vegetable oil enables the emulsion to have high wettability, the coagulum amount of the emulsion is reduced, and a small amount of acrylic ester soft monomer is matched for blending, so that the fluorine-containing block oligomer is successfully obtained.

The preferable technical scheme of the invention comprises one of the following steps:

the super-hydrophobic long-chain acrylic ester monomer accounts for 90-110wt% of the fluorine-containing monomer, and the acrylic ester soft monomer accounts for 20-30wt% of the fluorine-containing monomer;

and/or the fluorine-containing monomer is selected from one or more of hexafluorobutyl acrylate, hexafluoroisopropyl acrylate, octafluoropentyl acrylate, 12 fluoroheptyl acrylate, hexafluoroisopropyl methacrylate, octafluoropentyl methacrylate, 12 fluoroheptyl methacrylate, perfluorodecyl ethyl acrylate, perfluorobutyl ethyl acrylate and perfluoroalkyl ethyl methacrylate; preferably, the fluoromonomer is selected from hexafluorobutyl acrylate, hexafluoroisopropyl acrylate, octafluoropentyl acrylate;

and/or the superhydrophobic long-chain acrylate monomer is a C12-C18 alkyl ester, preferably selected from lauryl methacrylate, such as Terra C13-MA, BASF 1214F, or heptadecyl methacrylate, such as Terra C17.4-MA.

And/or the acrylic ester soft monomer comprises one or more of isooctyl acrylate, ethyl acrylate and butyl acrylate;

and/or the cardanol emulsifier is selected from cardanol sulfonate, cardanol sulfate, cardanol carboxylate or cardanol polyoxyethylene ether, preferably the cardanol emulsifier is selected from cardanol polyoxyethylene ether, and the dosage of the cardanol emulsifier is 3-8% of the total weight of the fluorine-containing monomer and the super-hydrophobic long-chain acrylate monomer, preferably 5-7%;

and/or the initiator is benzoyl peroxide, and the dosage of the initiator is 0.1-1% of the total weight of the fluorine-containing monomer and the super-hydrophobic long-chain acrylic ester monomer, preferably 0.6-0.8%;

in the whole preparation method, the addition amount of water is adjusted to 45-50% of the solid content of the finally prepared product.

The fluorine-containing block oligomer for preparing the aqueous pressure-sensitive adhesive is prepared by adopting the preparation method.

The aqueous pressure-sensitive adhesive is prepared by adopting the preparation method.

The aqueous pressure-sensitive adhesive is used as an adhesive of an ultralow surface energy material.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, a mode of preparing the copolymer by reacting the fluorine-containing monomer and the long-carbon-chain acrylic acid monomer is adopted, so that the low surface energy structure is better introduced into the acrylate main chain segment, the conversion efficiency of the fluorine-containing monomer and the distribution in the main chain segment are improved, and the wettability of the emulsion on the low surface energy surface is improved. The hydrophobicity of the emulsion is improved, the prepared aqueous pressure-sensitive adhesive has low surface energy, is suitable for film materials with low surface energy, has excellent wettability, avoids the problem of coating shrinkage cavity, and has good adhesion to a substrate.

Drawings

FIGS. 1 to 3 are photographs showing the state of the pressure-sensitive adhesive of example 1 at 1s, 5s and 10s, respectively, after coating;

FIGS. 4 to 6 are photographs showing the state of the pressure-sensitive adhesive of comparative example 2 at 1s, 3s and 5s, respectively, after coating;

FIGS. 7 to 8 are photographs showing the state of the pressure-sensitive adhesive of comparative example 1 at the 1 st and 3 rd s after coating, respectively.

Detailed Description

The invention will now be further illustrated by means of specific examples which are given solely by way of illustration of the invention and do not limit the scope thereof.

The raw materials or reagents not specifically described in the present invention are all conventional in the art and commercially available.

[ preparation of a fluorine-containing Block oligomer ]

Fluorine-containing Block oligomer a

250g of deionized water and 13.5g of cardanol polyoxyethylene ether (YGF-6 of Liaoning Kelong fine chemical company, inc.) are added into a reaction kettle, stirred and dispersed uniformly, 100g of hexafluorobutyl acrylate, 100g of lauryl methacrylate Terra C13-MA and 24g of isooctyl acrylate are added, the temperature is raised to 72 ℃, and 1.7g of initiating agent benzoyl peroxide is added for polymerization reaction for 3 hours, so that the product is obtained.

Fluorine-containing Block oligomer b

250g of deionized water and 11g of cardanol polyoxyethylene ether (YGF-6 of Liaoning Kelong fine chemical company, inc.) are added into a reaction kettle, stirred and dispersed uniformly, 100g of hexafluoroisopropyl acrylate, 90g of lauryl methacrylate BASF 1214F and 30g of butyl acrylate are added into the reaction kettle, the temperature is raised to 71 ℃, and 1.35g of initiating agent benzoyl peroxide is added for polymerization reaction for 4 hours, so that the product is obtained.

Fluorine-containing Block oligomer c

250g of deionized water and 17g of cardanol polyoxyethylene ether (YGF-6 of Liaoning Kelong fine chemical company, inc.) are added into a reaction kettle, stirred and dispersed uniformly, 115g of hexafluoroisopropyl acrylate, 100g of heptadecyl methacrylate Terra C17.4-MA and 30g of isooctyl acrylate are added into the reaction kettle, the temperature is raised to 73 ℃, 1.5g of initiator benzoyl peroxide is added into the reaction kettle for polymerization reaction for 3.5 hours, and the product is obtained.

Fluorine-containing block oligomer d

250g of deionized water and 16g of cardanol polyoxyethylene ether (YGF-6 of Liaoning Kelong fine chemical company, inc.) are added into a reaction kettle, stirred and dispersed uniformly, 105g of octafluoropentanyl acrylate, 100g of heptadecyl methacrylate Terra C17.4-MA and 28g of ethyl acrylate are added into the reaction kettle, the temperature is raised to 72 ℃, and 1.7g of initiating agent benzoyl peroxide is added for polymerization reaction for 3 hours, so that the product is obtained.

[ preparation of aqueous pressure-sensitive adhesive ]

Example 1

The aqueous pressure-sensitive adhesive was prepared as follows:

(a) Preparing kettle base solution: 35g of deionized water, 1.52g of sodium dodecyl benzene sulfonate and 0.22g of perfluorobutyl sulfonyl fluoride are weighed, added into a reaction kettle, stirred and heated to 85 ℃;

(b) Preparing a pre-emulsion: 45g of deionized water and 2.3g of Solvifer OT-75 are weighed, added into an emulsifying cylinder for stirring, 56.75g of mixed monomers (2.2 g of styrene, 53g of butyl acrylate, 0.75g of hydroxyethyl acrylate and 0.8g of acrylic acid) are added, and the mixture is stirred uniformly to prepare a pre-emulsion;

(c) Adding 4g of pre-emulsion into a reaction kettle, adding ammonium persulfate (0.2 g of ammonium persulfate is dissolved in 3g of deionized water), and preserving heat for 10 minutes;

(d) Simultaneously dropwise adding the residual pre-emulsion and ammonium persulfate (0.3 g of ammonium persulfate is dissolved in 5g of deionized water) into a reaction kettle within 4 hours, starting to dropwise add the fluorine-containing block oligomer a when the dropwise adding amount of the pre-emulsion reaches 55wt% of the total amount, keeping the temperature for 45 minutes after the dropwise adding is finished, and carrying out aftertreatment: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Example 2

The aqueous pressure-sensitive adhesive was prepared as follows:

(a) Preparing kettle base solution: 35g of deionized water, 1.6g of sodium dodecyl sulfate and 0.18g of perfluorohexyl sulfonamide are weighed, added into a reaction kettle, stirred and heated to 85 ℃;

(b) Preparing a pre-emulsion: 45g of deionized water and 2.4g of Solvifer OT-75 are weighed, added into an emulsifying cylinder for stirring, 56.45g of mixed monomers (2.8 g of styrene, 52g of butyl acrylate, 0.8g of hydroxyethyl acrylate and 0.85g of acrylic acid) are added, and the mixture is stirred uniformly to prepare a pre-emulsion;

(c) Adding 3.5g of the pre-emulsion into a reaction kettle, adding ammonium persulfate (0.2 g of ammonium persulfate is dissolved in 3g of deionized water), and preserving the heat for 10 minutes;

(d) Simultaneously dropwise adding the residual pre-emulsion and ammonium persulfate (0.3 g of ammonium persulfate is dissolved in 5g of deionized water) into a reaction kettle within 4 hours, starting to dropwise add the fluorine-containing block oligomer b when the dropwise adding amount of the pre-emulsion reaches 50wt% of the total amount, keeping the temperature for 40 minutes after the dropwise adding is finished, and performing aftertreatment: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Example 3

The aqueous pressure-sensitive adhesive was prepared as follows:

(a) Preparing kettle base solution: 35g of deionized water, 1.65g of sodium dodecyl sulfate and 0.19g of perfluorohexyl sulfonamide are weighed, added into a reaction kettle, stirred and heated to 85 ℃;

(b) Preparing a pre-emulsion: 45g of deionized water and 2.4g of sodium dodecyl sulfate are weighed, added into an emulsifying cylinder for stirring, 58.75g of mixed monomers (2.9 g of styrene, 54g of butyl acrylate, 0.9g of hydroxyethyl acrylate and 0.95g of acrylic acid) are added, and the mixture is stirred uniformly to prepare a pre-emulsion;

(c) Adding 5g of pre-emulsion into a reaction kettle, adding ammonium persulfate (0.15 g of ammonium persulfate is dissolved in 3g of deionized water), and preserving heat for 10 minutes;

(d) Simultaneously dropwise adding the residual pre-emulsion and ammonium persulfate (0.22 g of ammonium persulfate is dissolved in 5g of deionized water) into a reaction kettle within 4 hours, starting to dropwise add the fluorine-containing block oligomer c when the dropwise adding amount of the pre-emulsion reaches 60wt% of the total amount, keeping the temperature for 40 minutes after the dropwise adding is finished, and performing aftertreatment: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Example 4

The aqueous pressure-sensitive adhesive was prepared as follows:

(a) Preparing kettle base solution: 35g of deionized water, 1.64g of sodium dodecyl sulfate and 0.17g of perfluorohexyl sulfonamide are weighed, added into a reaction kettle, stirred and heated to 85 ℃;

(b) Preparing a pre-emulsion: 45g of deionized water and 2.4g of sodium dodecyl sulfate are weighed, added into an emulsifying cylinder for stirring, 58.25g of mixed monomers (2.9 g of styrene, 54g of butyl acrylate, 0.6g of hydroxybutyl acrylate and 0.75g of acrylamide) are added, and the mixture is stirred uniformly to prepare a pre-emulsion;

(c) Adding 4.8g of pre-emulsion into a reaction kettle, adding ammonium persulfate (0.2 g of ammonium persulfate is dissolved in 3g of deionized water), and preserving heat for 10 minutes;

(d) Simultaneously dropwise adding the residual pre-emulsion and ammonium persulfate (0.3 g of ammonium persulfate is dissolved in 5g of deionized water) into a reaction kettle within 3.5h, starting to dropwise add the fluorine-containing block oligomer d when the dropwise adding amount of the pre-emulsion reaches 56wt% of the total amount, keeping the temperature for 40min after the dropwise adding is finished, and carrying out aftertreatment: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Example 5

The aqueous pressure-sensitive adhesive was prepared as follows:

(a) Preparing kettle base solution: 35g of deionized water, 1.6g of sodium dodecyl benzene sulfonate and 0.24g of perfluorobutyl sulfonyl fluoride are weighed, added into a reaction kettle, stirred and heated to 85 ℃;

(b) Preparing a pre-emulsion: 45g of deionized water and 2.4g of Solvifer OT-75 are weighed, added into an emulsifying cylinder for stirring, 54.2g of mixed monomers (3 g of methyl methacrylate, 50g of butyl acrylate, 0.5g of hydroxyethyl acrylate and 0.7g of acrylic acid) are added, and the mixture is stirred uniformly to prepare a pre-emulsion;

(d) The remaining pre-emulsion and ammonium persulfate (0.3 g ammonium persulfate is dissolved in 5g deionized water) are added dropwise into the reaction kettle simultaneously within 3h, the fluorine-containing block oligomer a starts to be added dropwise when the adding amount of the pre-emulsion drops reaches 55wt% of the total amount, the total amount of the fluorine-containing block oligomer is 4.5g, the temperature is kept for 45min after the adding is finished, and the post-treatment is carried out: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Example 6

The aqueous pressure-sensitive adhesive was prepared as follows:

(a) Preparing kettle base solution: 35g of deionized water, 1.65g of sodium dodecyl benzene sulfonate and 0.25g of perfluorohexyl sulfonamide are weighed, added into a reaction kettle, stirred and heated to 85 ℃;

(b) Preparing a pre-emulsion: 45g of deionized water and 2.2g of AEO-9 are weighed, added into an emulsifying cylinder for stirring, 54.8g of mixed monomers (1.5 g of methacrylic acid, 52g of butyl acrylate, 0.55g of hydroxybutyl acrylate and 0.75g of acrylic acid) are added, and the mixture is stirred uniformly to prepare a pre-emulsion;

(c) Adding 4.5g of the pre-emulsion into a reaction kettle, adding ammonium persulfate (0.2 g of ammonium persulfate is dissolved in 3g of deionized water), and preserving the heat for 10 minutes;

(d) Simultaneously dropwise adding the residual pre-emulsion and ammonium persulfate (0.3 g of ammonium persulfate is dissolved in 5g of deionized water) into a reaction kettle within 3h, starting to dropwise add the fluorine-containing block oligomer c when the dropwise adding amount of the pre-emulsion reaches 50wt% of the total amount, keeping the temperature for 45min after the dropwise adding is finished, and performing aftertreatment: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Comparative example 1

In comparison with example 1, the aqueous pressure-sensitive adhesive was prepared in the following manner without adding the fluorine-containing block oligomer a in step (d) and in the same manner as in example 1:

(d) Simultaneously dropwise adding the residual pre-emulsion and ammonium persulfate (0.3 g of ammonium persulfate is dissolved in 5g of deionized water) into the reaction kettle within 4 hours, and preserving the heat for 45 minutes after the dropwise adding, and carrying out post-treatment: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Comparative example 2

In comparison with example 1, in step (d) the fluorine-containing block oligomer a was replaced with an equivalent amount of hexafluorobutyl acrylate, and the rest was the same as in example 1, and an aqueous pressure-sensitive adhesive was prepared specifically as follows:

the aqueous pressure-sensitive adhesive was prepared as follows:

(d) Simultaneously dropwise adding the residual pre-emulsion and ammonium persulfate (0.3 g of ammonium persulfate is dissolved in 5g of deionized water) into a reaction kettle within 4 hours, starting to dropwise add hexafluorobutyl acrylate when the dropwise adding amount of the pre-emulsion reaches 55wt% of the total amount, keeping the temperature for 45 minutes after the dropwise adding is finished, and performing aftertreatment: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Comparative example 3

In comparison with example 1, the timing of adding the fluorine-containing block oligomer a in the step (d) was advanced, and the fluorine-containing block oligomer a was started to be added dropwise when the amount of the pre-emulsified liquid added was 40% by weight of the total amount, and the rest was the same as in example 1, and specifically an aqueous pressure-sensitive adhesive was produced as follows:

(d) The remaining pre-emulsion and ammonium persulfate (0.3 g ammonium persulfate is dissolved in 5g deionized water) are added dropwise into the reaction kettle simultaneously within 4h, the fluorine-containing block oligomer a starts to be added dropwise when the adding amount of the pre-emulsion drops reaches 40wt% of the total amount, the total amount of the fluorine-containing block oligomer is 4.5g, the temperature is kept for 45min after the adding is finished, and the post-treatment is carried out: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Comparative example 4

In comparison with example 1, the timing of adding the fluorine-containing block oligomer a in the step (d) was delayed, and the fluorine-containing block oligomer a was started to be added dropwise when the amount of the pre-emulsified liquid added was 65% by weight of the total amount, and the rest was the same as in example 1, and specifically an aqueous pressure-sensitive adhesive was produced as follows:

(d) The remaining pre-emulsion and ammonium persulfate (0.3 g ammonium persulfate is dissolved in 5g deionized water) are added dropwise into the reaction kettle simultaneously within 4h, the fluorine-containing block oligomer a starts to be added dropwise when the adding amount of the pre-emulsion drops reaches 65wt% of the total amount, the total amount of the fluorine-containing block oligomer is 4.5g, the temperature is kept for 45min after the adding is finished, and the post-treatment is carried out: and simultaneously dropwise adding an oxidant and a reducing agent, wherein the oxidant is tert-butyl hydroperoxide (0.2 g of tert-butyl hydroperoxide is dissolved in 2g of deionized water), the reducing agent is a hanging white block (0.12 g of hanging white block is dissolved in 2g of deionized water), cooling to below 50 ℃ after reacting for 30min, adding ammonia water to neutralize pH to 7.5, and finally filtering and discharging to obtain the water-based pressure-sensitive adhesive.

Comparative example 5

In comparison with example 1, 0.22g of perfluorobutyl sulfonyl fluoride in step (a) was replaced with an equivalent amount of sodium dodecylbenzenesulfonate, and the remainder were the same as in example 1, to prepare an aqueous pressure-sensitive adhesive in particular as follows:

(a) Preparing kettle base solution: 35g of deionized water and 1.74g of sodium dodecyl benzene sulfonate are weighed, added into a reaction kettle, stirred and heated to 85 ℃;

[ Water-based pressure-sensitive adhesive Performance test ]

The aqueous pressure-sensitive adhesives prepared in each of the examples and comparative examples were subjected to product performance testing according to the following methods.

Wetting ability test: the aqueous pressure-sensitive adhesive was uniformly coated on the PET release film by a small coater using a 25 bar, and the time of first occurrence of shrinkage cavity or shrinkage edge was observed and recorded, and the specific test results are shown in Table 1.

In the examples, FIGS. 1 to 3 are respectively photographs showing the state of the pressure-sensitive adhesive obtained in example 1 after being uniformly coated on the surface of the PET release film, at the 1 st, 5 th and 10 th s, and edge shrinkage occurs at the 10 th s;

in the comparative examples, FIGS. 4 to 6 are photographs showing the state of 1s, 3s and 5s after the pressure-sensitive adhesive obtained in comparative example 2 was uniformly coated on the surface of the PET release film, respectively, and edge shrinkage occurred at 3 s;

FIGS. 7 to 8 are photographs showing the state of the pressure-sensitive adhesive of comparative example 1 after the pressure-sensitive adhesive was uniformly applied to the surface of the PET release film at the 1 st and 3 rd positions, respectively, and shrinkage cavity and edge shrinkage occurred at the same time (. Ltoreq.1 s) when the pressure-sensitive adhesive was applied.

Samples of each example with satisfactory wetting ability were prepared and further tested for adhesive properties.

Coating a release film on the prepared pressure-sensitive adhesive emulsion by using a 50# wire rod, placing the sample in a 100 ℃ oven for 3min, and then coating 50-micrometer PET (polyethylene terephthalate) in a conversion mode to prepare a glue film sample with a dry glue thickness of 25+/-1 micrometer for subsequent physical property testing, wherein the following concrete steps are as follows:

initial peel force was tested according to GB 2792-2014; the initial adhesion is tested according to GB/T4852-2002, and the ball number is used for representing the initial adhesion; the holding power was measured according to GB4851-2014 and expressed in terms of drop time, and the specific results are shown in Table 1.

TABLE 1 results of product Performance test

	Shrinkage cavity edge/s	Complete wetting/s	Initial peel force (N/25 mm)	Initial adhesion	Holding power of adhesion
						Example 1	≥10	3	8.4	15#	≥72h
Example 2	≥9	3	8.1	13#	≥72h
						Example 3	≥8	4	7.4	14#	≥72h
Example 4	≥7	5	7.6	13#	≥72h
						Example 5	≥8	4	7.8	15#	≥72h
Example 6	≥7	5	7.4	14#	≥72h
						Comparative example 1	≤1	--	--	--	--
Comparative example 2	≤3	--	--	--	--
						Comparative example 3	≤4	--	--	--	--
Comparative example 4	≤4	--	--	--	--
						Comparative example 5	≤4	--	--	--	--

As can be seen from Table 1, the aqueous pressure-sensitive adhesive prepared by the embodiment of the invention has excellent wettability to low surface energy materials, does not have the problem of coating shrinkage cavity in a long time, can meet the requirements of a production transfer coating process, and the prepared adhesive film has excellent three-force balance performance and meets the requirements of mechanical properties.

The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.

Claims

1. The preparation method of the aqueous pressure-sensitive adhesive is characterized by comprising the following steps of:

2. The method for preparing an aqueous pressure-sensitive adhesive according to claim 1, wherein the timing of adding the fluorine-containing block oligomer in the step (2) to the polymerization system is as follows: when the pre-emulsified liquid is added in an amount of 50-60wt%, the mixture is added until the polymerization process is completed.

3. The method for preparing the aqueous pressure-sensitive adhesive according to claim 1, wherein the method for preparing the aqueous pressure-sensitive adhesive comprises the following specific steps:

(c) Adding 2-5wt% of pre-emulsion into a reaction kettle, adding an initiator 1, and performing polymerization for 5-25 minutes;

the step (a) and the step (b) are not sequenced.

4. The method for preparing an aqueous pressure-sensitive adhesive according to claim 3, wherein the amount of the emulsifier 1 is 2-5wt% based on the total weight of all monomers in the pot base solution; the water dosage is 18-22 times of that of the emulsifier 1;

5. The method for preparing an aqueous pressure-sensitive adhesive according to claim 3, wherein the amount of the emulsifier 2 in the pre-emulsion is 3 to 5wt% based on the total weight of all monomers; the water is 18-22 times of the emulsifier 2, and the emulsifier 2 comprises an anionic emulsifier and/or a nonionic emulsifier;

the addition amount of the fluorine-containing block oligomer is 5-20%, preferably 6-9% of the total amount of the mixed monomers;

the functional monomer is selected from one or more of acrylic acid, acrylamide, hydroxybutyl acrylate, hydroxypropyl acrylate and hydroxyethyl acrylate; further preferred is a mixture of acrylic acid and hydroxyethyl acrylate.

6. The method for preparing an aqueous pressure-sensitive adhesive according to claim 3, wherein the initiator 1 and the initiator 2 are one or more selected from the group consisting of ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, t-butyl hydroperoxide, BPO, AIBN;

preferably, the initiator 1 and the initiator 2 adopt ammonium persulfate, and the dosage of the initiator 1 is 0.1-1wt% of the mixed monomer; the amount of the initiator 2 is 0.2-1wt% of the mixed monomer;

7. The method for preparing the aqueous pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the fluorine-containing block oligomer is prepared by aqueous phase copolymerization, and the specific method comprises: adding water and cardanol emulsifying agent into a reaction kettle, stirring and dispersing uniformly, keeping a stirring state, adding fluorine-containing monomer, super-hydrophobic long-chain acrylic ester monomer and acrylic ester soft monomer, heating to 60-75 ℃, adding initiator, and performing polymerization reaction for 2-4 hours to obtain the product.

8. The method for preparing an aqueous pressure-sensitive adhesive according to claim 7, comprising one of the following:

and/or the super-hydrophobic long-chain acrylic ester monomer is C12-C18 alkyl ester, preferably selected from lauryl methacrylate or heptadecyl methacrylate;

and/or the cardanol emulsifier is selected from cardanol sulfonate, cardanol sulfate, cardanol carboxylate or cardanol polyoxyethylene ether, and the dosage of the cardanol emulsifier is 3-8% of the total weight of the fluorine-containing monomer and the super-hydrophobic long-chain acrylate monomer, preferably 5-7%;

9. A fluorine-containing block oligomer for preparing an aqueous pressure-sensitive adhesive, characterized by being prepared by using the preparation method as claimed in claim 7 or 8.

10. An aqueous pressure-sensitive adhesive prepared by the preparation method according to any one of claims 1 to 8.

11. The use of an aqueous pressure sensitive adhesive as claimed in claim 10, wherein the aqueous pressure sensitive adhesive is used as an adhesive for ultra low surface energy materials.