A polymer emulsion tackifier and its preparation method and application

Abstract

The present invention provides a polymer emulsion thickener and a preparation method and application thereof. The raw materials for preparing the polymer emulsion thickener include a first acrylate monomer, a second acrylate monomer, a third acrylate monomer, a fourth acrylate monomer, an initiator and an emulsifier; the second acrylate monomer includes an isocyanate-modified acrylate monomer. In the present invention, the polymer emulsion thickener uses an isocyanate-modified acrylate monomer as a raw material, and multiple acrylate monomers are coordinated with each other, so that the obtained polymer emulsion thickener has good compatibility with acrylic adhesives, and improves the peel strength and wetting performance between the adhesive and the substrate, and has a wide range of applications.

Description

Technical Field

[0001] The invention belongs to the technical field of tackifiers, and in particular relates to a polymer emulsion tackifier and a preparation method and application thereof. Background Art

[0002] Water-based acrylic emulsion adhesives have the advantages of being non-toxic, simple in synthesis process, low in production cost, strong in product bonding adaptability, fast in drying and film-forming rate, and environmentally friendly and pollution-free. Therefore, they play an important role in the adhesive industry, especially in the fields of pressure-sensitive adhesives, paper / plastic laminating adhesives, floor adhesives, and automotive interior adhesives. However, due to the characteristics of the linear molecular structure of polyacrylate emulsions, they have certain defects in terms of bonding performance and wettability with different substrates.

[0003] In the prior art, in order to broaden and improve the application performance and field of acrylic emulsion adhesives, water-based tackifying emulsions are usually added to improve the initial adhesion, holding force and peel strength of the adhesive. Among them, the most widely used are rosin series resins, terpene resins, etc., and the tackifiers are mostly added to the water-based acrylic ester emulsion in the form of physical blending, generally accounting for 15-20%. For example, CN108084937A discloses an epoxy acrylic adhesive, including a tackifier water-based tackifying rosin resin or a multi-carbon tackifying resin. And CN102701982A discloses a method for synthesizing a tackifier monomer using terpinene, a byproduct of terpinene alcohol, using turpentine oil to produce terpinene, a byproduct of terpinene alcohol, through addition and esterification reactions, a tackifier is synthesized, which can be applied to acrylic water-based coatings or adhesives as a tackifier monomer or a tackifier monomer for hot melt adhesives, and has good application value. However, the tackifier has poor compatibility with acrylic acid, and the bonding strength of the obtained acrylic adhesive needs to be further improved.

[0004] The common defects in the prior art are that the bonding strength of rosin series resins and terpene resin tackifiers is not high, and their compatibility with acrylic emulsions is poor, which can easily cause phase separation problems after the adhesive is formed into a film, resulting in reduced film uniformity, poor bonding effect, unstable performance, and cannot effectively meet the market requirements for adhesives.

[0005] Therefore, developing an aqueous polymer emulsion tackifier that has good compatibility with acrylic adhesives and is beneficial to improving the peel strength of acrylic adhesives and extending the action time is a technical problem that needs to be solved urgently in the field. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a polymer emulsion thickener and a preparation method and application thereof. The polymer emulsion thickener uses isocyanate-modified acrylate monomers as raw materials, and multiple acrylate monomers are coordinated with each other, so that the obtained polymer emulsion thickener has good compatibility with acrylic adhesives, and improves the peel strength and wetting performance of the adhesive and the substrate. With a small amount of use, the adhesive can have high initial adhesion, peel strength and long adhesion time, and has a wide range of applications.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a polymer emulsion thickener, wherein raw materials for preparing the polymer emulsion thickener include a first acrylate monomer, a second acrylate monomer, a third acrylate monomer, a fourth acrylate monomer, an initiator and an emulsifier; the second acrylate monomer includes an isocyanate-modified acrylate monomer.

[0009] In the present invention, acrylate monomers are modified by using isocyanate to obtain acrylate monomers with polyurethane properties, so that the polymer emulsion has the characteristics of high adhesion, high peel strength and excellent temperature stability of polyurethane; and through the mutual coordination of various acrylate monomers, the obtained polymer emulsion thickener not only has good compatibility with acrylic adhesives to avoid phase separation, but also can improve the wettability and bonding performance of the adhesive to the substrate, thereby achieving a good replacement for natural emulsion thickeners.

[0010] Preferably, the isocyanate-modified acrylate monomer has a comb-shaped structure.

[0011] Preferably, the raw materials for preparing the isocyanate-modified acrylic ester monomer include hydroxyl-containing acrylic ester monomer, isocyanate and polymer polyol.

[0012] Preferably, the molar ratio of the hydroxyl-containing acrylic monomer, isocyanate and polymer polyol is 1:(1-1.1):(1.1-1.2), wherein the specific value in (1-1.1) can be, for example, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, etc.; the specific value in (1.1-1.2) can be, for example, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, etc.

[0013] Preferably, the hydroxyl-containing acrylic ester monomer includes at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate, and more preferably hydroxyethyl acrylate and / or hydroxypropyl acrylate.

[0014] Preferably, the isocyanate comprises a diisocyanate.

[0015] Preferably, the isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate, and more preferably hexamethylene diisocyanate and / or isophorone diisocyanate.

[0016] Preferably, the number average molecular weight of the polymer polyol is 200-600, for example, 220, 250, 280, 300, 320, 350, 380, 400, 420, 450, 480, 500, 520, 550, 580, etc.

[0017] Preferably, the polymer polyol comprises a polyether polyol.

[0018] Preferably, the polyether polyol comprises polyethylene glycol and / or polypropylene glycol.

[0019] Preferably, the isocyanate-modified acrylate monomer is prepared by the following method, which comprises:

[0020] (i) reacting isocyanate with a hydroxyl-containing acrylic ester monomer to obtain a reactant 1;

[0021] (ii) reacting the reactant 1 obtained in step (i) with a polymer polyol to obtain the isocyanate-modified acrylate monomer.

[0022] Preferably, the reaction in step (i) is carried out in the presence of a protective atmosphere.

[0023] In the present invention, the protective atmosphere includes but is not limited to nitrogen.

[0024] Preferably, the reaction system in step (i) further comprises a catalyst and an inhibitor.

[0025] Preferably, the content of the catalyst is 0.05-0.3% of the mass of the isocyanate, for example, it can be 0.1%, 0.15%, 0.2%, 0.25%, etc.

[0026] Preferably, the catalyst comprises an organometallic catalyst.

[0027] Preferably, the organic metal catalyst includes at least one of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dibutyrate or dioctyltin dilaurate.

[0028] Preferably, the content of the polymerization inhibitor is 0.05-0.15% of the mass of the hydroxyl-containing acrylic ester monomer, for example, it can be 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.12%, 0.14%, etc.

[0029] Preferably, the polymerization inhibitor includes at least one of hydroquinone, p-benzoquinone, p-hydroxyanisole or tert-butylhydroquinone.

[0030] Preferably, the reaction temperature in step (i) is 30-60°C, for example, 35°C, 40°C, 45°C, 50°C, 55°C, etc.

[0031] Preferably, the reaction time of step (i) is 1 to 3 h, for example, 1.5 h, 2 h, 2.5 h, etc.

[0032] Preferably, the reaction temperature in step (ii) is 60-80°C, for example, 65°C, 70°C, 75°C, etc.

[0033] Preferably, the reaction time of step (ii) is 1 to 2 h, for example, 1.2 h, 1.4 h, 1.6 h, 1.8 h, etc.

[0034] Preferably, the first acrylate monomer includes C2-C15 alkyl acrylate, wherein C2-C15 can be, for example, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, etc.

[0035] Preferably, the first acrylic acid ester monomer includes at least one of ethyl acrylate, butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate or lauric acrylate, preferably butyl acrylate.

[0036] Preferably, the third acrylic acid ester monomer includes an acrylic acid ester monomer containing a hydroxyl group and / or an amino group.

[0037] Preferably, the third acrylic acid ester monomer includes hydroxyethyl acrylate and / or hydroxypropyl acrylate.

[0038] Preferably, the fourth acrylic acid ester monomer includes a carboxyl group-containing acrylic acid ester monomer.

[0039] Preferably, the carboxyl group-containing acrylate monomer includes β-acryloxy propionic acid and / or β-methacryloxy propionic acid, preferably β-acryloxy propionic acid.

[0040] Preferably, the mass ratio of the first acrylate monomer, the second acrylate monomer, the third acrylate monomer and the fourth acrylate monomer is 100:(30-50):(5-10):(10-20), wherein the specific value in (30-50) can be, for example, 32, 34, 36, 38, 40, 42, 44, 46, 48, etc.; the specific value in (5-10) can be, for example, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, etc.; the specific value in (10-20) can be, for example, 11, 12, 13, 14, 15, 16, 17, 18, 19, etc.

[0041] In the present invention, by selecting a second acrylate monomer, a third acrylate monomer, and a fourth acrylate monomer containing functional groups, the side chain of the polymer emulsion thickener contains functional groups such as carbamate, epoxy, ester, hydroxyl, amino, and carboxyl groups, which greatly improves the wetting and bonding ability of the emulsion to the adhesive substrate, promotes the interaction between the adhesive emulsion and the substrate, thereby significantly improving the bonding force and peel strength of the adhesive, and achieving a good replacement for the natural emulsion thickener.

[0042] Preferably, the amount of the initiator used is 0.1-1% of the total mass of the monomers, for example, 0.2%, 0.4%, 0.6%, 0.8%, etc.

[0043] Preferably, the initiator comprises at least one of a peroxide initiator, an azo initiator or a redox initiator.

[0044] Preferably, the initiator comprises at least one of potassium persulfate, ammonium persulfate, potassium persulfate-sodium sulfite, hydrogen peroxide or azobisisobutylamidine hydrochloride, preferably potassium persulfate and / or ammonium persulfate.

[0045] Preferably, the content of the emulsifier is 0.2-1% of the total mass of the monomers, for example, 0.4%, 0.6%, 0.8%, etc.

[0046] Preferably, the emulsifier comprises an anionic emulsifier and / or a nonionic emulsifier.

[0047] Preferably, the emulsifier includes at least one of alkylphenol polyoxyethylene ether, alkylphenol polyoxyethylene ether ammonium sulfate, ethoxylated alkyl sulfate sodium salt or polyoxyethylene ether castor oil ester.

[0048] Preferably, the raw materials for preparing the polymer emulsion tackifier also include a chain transfer agent.

[0049] Preferably, the amount of the chain transfer agent is 0.5-3% of the total weight of the monomers, for example, 0.6%, 0.8%, 1%, 1.5%, 2%, 2.5%, etc.

[0050] Preferably, the chain transfer agent comprises a mercapto compound.

[0051] Preferably, the chain transfer agent includes at least one of butyl mercaptan, tert-butyl mercaptan, dodecyl mercaptan, mercaptoethanol or mercaptopropionic acid, and mercaptoethanol and / or mercaptopropionic acid are more preferred.

[0052] In a second aspect, the present invention provides a method for preparing the polymer tackifier according to the first aspect, the preparation method comprising:

[0053] (1) mixing a first acrylic ester monomer, a second acrylic ester monomer, a third acrylic ester monomer, a fourth acrylic ester monomer, an emulsifier and a solvent, and pre-emulsifying the mixture to obtain a monomer pre-emulsion;

[0054] (2) mixing 10 to 30% (for example, 10%, 15%, 20%, 25%, 30%, etc.) of the total mass of the monomer pre-emulsion obtained in step (1) with 30 to 50% (for example, 35%, 40%, 45%, etc.) of the initiator, and subjecting the mixture to polymerization reaction to obtain a seed emulsion;

[0055] (3) The seed emulsion obtained in step (2) is mixed with the remaining monomer pre-emulsion and the remaining initiator, and reacted to obtain the polymer emulsion thickener.

[0056] Preferably, the mixed raw materials in step (1) further include a chain transfer agent.

[0057] Preferably, the pre-emulsification method in step (1) comprises shear emulsification.

[0058] Preferably, the shearing rotation speed is 300-800 r / min, for example, it can be 350 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min, 600 r / min, 650 r / min, 700 r / min, 750 r / min, etc.

[0059] Preferably, the polymerization reaction temperature in step (2) is 50-80°C, for example, 55°C, 60°C, 65°C, 70°C, 75°C, etc.

[0060] Preferably, the polymerization reaction time in step (2) is 1 to 3 hours, for example, 1.5 hours, 2 hours, 2.5 hours, etc.

[0061] Preferably, the mixing in step (3) comprises sequentially dropping the remaining monomer pre-emulsion and the remaining initiator into the seed emulsion.

[0062] Preferably, the dropwise addition time of the remaining monomer pre-emulsion is 3 to 5 hours, for example, 3.5 hours, 4 hours, 4.5 hours, etc.

[0063] Preferably, the remaining initiator is added dropwise for 4 to 6 hours, for example, 4.5 hours, 5 hours, 5.5 hours, etc.

[0064] Preferably, the reaction temperature in step (3) is 55-95°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.

[0065] Preferably, the reaction time of step (3) is 2 to 5 h, for example, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, etc.

[0066] Preferably, the solid content of the polymer emulsion tackifier is 40-60%, for example, 45%, 50%, 55%, etc.

[0067] In a third aspect, the present invention provides an acrylate adhesive, comprising an acrylic masterbatch emulsion and the polymer emulsion tackifier as described in the first aspect.

[0068] Preferably, the effective mass percentage of the polymer emulsion tackifier in the acrylic adhesive is 2-6%, for example, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, etc.

[0069] In the present invention, the effective mass percentage refers to the mass content excluding the solvent.

[0070] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] The polymer tackifier emulsion provided by the present invention uses isocyanate-modified acrylate monomers as raw materials, and multiple acrylate monomers are coordinated with each other to make the obtained polymer emulsion tackifier have good compatibility with acrylic adhesives, avoiding the phenomenon of phase separation; and improves the wetting and bonding ability of the emulsion to the adhesive substrate, promotes the interaction between the adhesive emulsion and the substrate, thereby significantly improving the bonding force and peel strength of the adhesive, and achieving a good replacement for natural emulsion tackifiers. DETAILED DESCRIPTION

[0073] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0074] Preparation Example 1

[0075] An isocyanate-modified acrylate monomer. The raw materials for preparing the isocyanate-modified acrylate monomer include 176.4g of hexamethylene diisocyanate, 116g of hydroxyethyl acrylate, 220g of polyethylene glycol 200, 0.088g of stannous octoate and 0.058g of hydroquinone.

[0076] The preparation method of the isocyanate-modified acrylate monomer comprises:

[0077] Under a nitrogen environment, hexamethylene diisocyanate and stannous octoate were weighed into a flask, the temperature was raised to 30° C., hydroxyethyl acrylate monomer containing hydroquinone was added dropwise, and after reacting for 3 hours, polyethylene glycol 200 was added, and end-capping treatment was performed at 70° C. The reaction was continued for 2 hours to obtain the isocyanate-modified acrylate monomer.

[0078] Preparation Example 2

[0079] An isocyanate-modified acrylic ester monomer. The raw materials for preparing the isocyanate-modified acrylic ester monomer include 244.5 g of isophorone diisocyanate, 130 g of hydroxypropyl acrylate, 720 g of polyethylene glycol 600, 0.48 g of dibutyltin dilaurate and 0.13 g of hydroquinone.

[0080] The preparation method of the isocyanate-modified acrylate monomer comprises:

[0081] Under a nitrogen environment, isophorone diisocyanate and dibutyltin dilaurate were weighed into a flask, the temperature was raised to 50° C., hydroxypropyl acrylate monomer containing hydroquinone was added dropwise, and after reacting for 2 hours, polyethylene glycol 600 was added, and end-capping treatment was performed at 60° C. The reaction was continued for 2 hours to obtain the isocyanate-modified acrylate monomer.

[0082] Preparation Example 3

[0083] An isocyanate-modified acrylic ester monomer. The raw materials for preparing the isocyanate-modified acrylic ester monomer include 201g of xylylene diisocyanate, 130g of hydroxyethyl methacrylate, 460g of polypropylene glycol 400, 0.6g of dibutyltin diacetate and 0.195g of hydroquinone.

[0084] The preparation method of the isocyanate-modified acrylate monomer comprises:

[0085] Under a nitrogen environment, xylene diisocyanate and dibutyltin diacetate were weighed into a flask, the temperature was raised to 60° C., hydroxyethyl methacrylate monomer containing hydroquinone was added dropwise, and after reacting for 1 hour, polypropylene glycol 400 was added, and end-capping treatment was performed at 80° C. The reaction was continued for 1 hour to obtain the isocyanate-modified acrylate monomer.

[0086] Preparation Example 4

[0087] An isocyanate-modified acrylate monomer, which differs from Preparation Example 1 only in that the polyethylene glycol 200 is replaced by ethylene glycol with an equal molar amount of hydroxyl groups, and other raw materials, amounts and preparation methods are the same as those in Preparation Example 1.

[0088] Preparation Example 5

[0089] An isocyanate-modified acrylate monomer, which differs from Preparation Example 1 only in that the polyethylene glycol 200 is replaced by polyethylene glycol 800 with an equal molar amount of hydroxyl groups, and other raw materials, amounts and preparation methods are the same as those in Preparation Example 1.

[0090] Preparation Example 6

[0091] An isocyanate-modified acrylate monomer, which differs from Preparation Example 1 only in that the polyethylene glycol 200 is replaced by pentaerythritol with an equal molar amount of hydroxyl groups, and other raw materials, amounts and preparation methods are the same as those in Preparation Example 1.

[0092] Preparation Example 7

[0093] An isocyanate-modified acrylic ester monomer, which differs from Preparation Example 1 only in that the polyethylene glycol 200 is replaced by pentaerythritol with an equal molar amount of hydroxyl groups. The preparation method comprises: under a nitrogen environment, weighing isophorone diisocyanate and dibutyltin dilaurate into a flask, adding pentaerythritol, reacting at 60° C. for 2 hours, then dropwise adding hydroxypropyl acrylate monomer containing hydroquinone thereto, and reacting at 50° C. for 2 hours to obtain the isocyanate-modified acrylic ester monomer.

[0094] Example 1

[0095] The present embodiment provides a polymer emulsion thickener, wherein the raw materials for preparing the polymer emulsion thickener include 100g butyl acrylate, 50g isocyanate-modified acrylate monomer (Preparation Example 1), 5g hydroxyethyl acrylate, 15g β-acryloxypropionic acid, 2.55g mercaptopropionic acid, 0.85g alkylphenol polyoxyethylene ether and 0.17g potassium persulfate.

[0096] This embodiment provides a method for preparing the polymer emulsion tackifier, which specifically includes:

[0097] (1) 100 g of butyl acrylate, 50 g of isocyanate-modified acrylate monomer, 5 g of hydroxyethyl acrylate, 15 g of β-acryloxypropionic acid, 2.55 g of mercaptopropionic acid, 0.85 g of alkylphenol polyoxyethylene ether and 252 g of pure water were mixed and sheared and emulsified to obtain a monomer pre-emulsion;

[0098] (2) adding 128 g of the monomer pre-emulsion obtained in step (1) and 0.085 g of potassium persulfate into a flask, heating to 50° C. to initiate polymerization, and reacting for 3 hours to obtain a blue-white seed emulsion;

[0099] (3) adding the remaining monomer pre-emulsion and potassium persulfate solution (0.085 g potassium persulfate dissolved in 10 g water) to the blue-white seed emulsion obtained in step (2), wherein the monomer pre-emulsion is added for 3 hours and the potassium persulfate solution is added for 4 hours; after the addition is completed, the mixture is kept warm at 65° C. for 4 hours, and some water is removed under reduced pressure to obtain a blue light emulsion with a solid content of 50.6%, which is the polymer emulsion thickener.

[0100] Example 2

[0101] The present embodiment provides a polymer emulsion thickener, wherein the raw materials for preparing the polymer emulsion thickener include 100g of 2-ethylhexyl acrylate, 40g of isocyanate-modified acrylate monomer (Preparation Example 2), 10g of hydroxypropyl acrylate, 10g of β-methacryloyloxypropionic acid, 0.8g of mercaptoethanol, 0.32g of alkylphenol polyoxyethylene ether ammonium sulfate and 0.3g of ammonium persulfate.

[0102] This embodiment provides a method for preparing the polymer emulsion tackifier, which specifically includes:

[0103] (1) 100 g of 2-ethylhexyl acrylate, 40 g of isocyanate-modified acrylate monomer, 10 g of hydroxypropyl acrylate, 10 g of β-methacryloxypropionic acid, 0.8 g of mercaptoethanol, 0.32 g of alkylphenol polyoxyethylene ether ammonium sulfate and 68 g of pure water were mixed and sheared and emulsified to obtain a monomer pre-emulsion;

[0104] (2) adding 22.9 g of the monomer pre-emulsion obtained in step (1) and 0.12 g of ammonium persulfate into a flask, heating to 70° C. to initiate polymerization, and reacting for 2 hours to obtain a blue-white seed emulsion;

[0105] (3) adding the remaining monomer pre-emulsion and ammonium persulfate solution (0.18 g of ammonium persulfate dissolved in 90 g of water) to the blue-white seed emulsion obtained in step (2) dropwise for 5 hours; after the addition is completed, the mixture is kept warm at 80° C. for 5 hours to obtain a blue light emulsion with a solid content of 50.3%, which is the polymer emulsion thickener.

[0106] Example 3

[0107] The present embodiment provides a polymer emulsion thickener, wherein the raw materials for preparing the polymer emulsion thickener include 100g of isooctyl acrylate, 30g of isocyanate-modified acrylate monomer (Preparation Example 3), 8g of hydroxyethyl acrylate, 20g of β-acryloxypropionic acid, 4.74g of dodecyl mercaptan, 1.58g of alkylphenol polyoxyethylene ether and 1.58g of potassium persulfate.

[0108] This embodiment provides a method for preparing the polymer emulsion tackifier, which specifically includes:

[0109] (1) 100 g of isooctyl acrylate, 30 g of isocyanate-modified acrylate monomer, 8 g of hydroxyethyl acrylate, 20 g of β-acryloxypropionic acid, 4.74 g of dodecyl mercaptan, 1.58 g of alkylphenol polyoxyethylene ether and 123 g of pure water were mixed and sheared and emulsified to obtain a monomer pre-emulsion;

[0110] (2) adding 57.5 g of the monomer pre-emulsion obtained in step (1) and 0.48 g of potassium persulfate into a flask, heating to 80° C. to initiate polymerization, and reacting for 1 hour to obtain a blue-white seed emulsion;

[0111] (3) adding the remaining monomer pre-emulsion and potassium persulfate solution (1.1 g potassium persulfate dissolved in 29 g water) to the blue-white seed emulsion obtained in step (2), wherein the monomer pre-emulsion is added for 4 hours and the potassium persulfate solution is added for 6 hours; after the addition is completed, the mixture is kept warm at 85° C. for 2 hours to obtain a blue light emulsion with a solid content of 50.5%, which is the polymer emulsion thickener.

[0112] Embodiment 4-7

[0113] Example 4-7 provides a polymer emulsion thickener, which differs from Example 1 only in that the isocyanate-modified acrylate monomer is an isocyanate-modified acrylate monomer of equal mass provided in Preparation Example 4-7, and other raw materials, amounts and preparation methods are the same as those in Example 1.

[0114] Example 8

[0115] This embodiment provides a polymer emulsion thickener, which is different from Embodiment 1 only in that the total amount of the monomers remains unchanged, the mass ratio of the first acrylate monomer, the second acrylate monomer, the third acrylate monomer, and the fourth acrylate monomer is 100:20:20:30, and other raw materials, amounts, and preparation methods are the same as those in Embodiment 1.

[0116] Example 9

[0117] This embodiment provides a polymer emulsion thickener, which is different from Embodiment 1 only in that the total amount of the monomers remains unchanged, the mass ratio of the first acrylate monomer, the second acrylate monomer, the third acrylate monomer, and the fourth acrylate monomer is 100:60:2:8, and other raw materials, amounts, and preparation methods are the same as those in Embodiment 1.

[0118] Comparative Example 1

[0119] This comparative example provides a polymer emulsion tackifier, which differs from Example 1 only in that the isocyanate-modified acrylate monomer is replaced with an equal mass of hydroxyethyl acrylate, and other raw materials, amounts and preparation methods are the same as those in Example 1.

[0120] Comparative Example 2

[0121] This comparative example provides a polymer emulsion thickener, which is different from Example 1 only in that the total amount of the isocyanate-modified acrylate monomer, hydroxyethyl acrylate and β-acryloxypropionic acid remains unchanged, hydroxyethyl acrylate and β-acryloxypropionic acid are omitted, and other raw materials, amounts used and preparation methods are the same as those in Example 1.

[0122] Performance Testing

[0123] BASF Acronal AV 215ap was used as the acrylic masterbatch emulsion, and different amounts of the polymer emulsion tackifiers provided in Examples 1 to 9 and Comparative Examples 1 to 2 were added to perform the following test; wherein, the American Laughter 780G water-based rosin tackifier emulsion was used as the comparative sample; wherein, “-” means that no tackifier was added, and only the acrylic masterbatch emulsion was used;

[0124] (1) Initial adhesion: tested according to ASTM D3121-17;

[0125] (2) 180°C peel strength: tested in accordance with GB / T 25256;

[0126] (3) Adhesion: Tested in accordance with GB / T 48514.

[0127] The specific test results are shown in Table 1:

[0128] Table 1

[0129]

[0130]

[0131] As can be seen from the above table, the polymer emulsion tackifier provided by the present invention selects isocyanate-modified acrylate monomers as raw materials, and cooperates with multiple acrylate monomers to make the obtained polymer emulsion tackifier have good compatibility with acrylic adhesives. With a small amount, the peel strength and wetting performance between the adhesive and the substrate can be improved, and the adhesive has a large initial adhesion and a long adhesion time. It can be seen from Groups 1-4 that when the content of the polymer emulsion tackifier is between 5 and 10%, the initial adhesion of the adhesive can reach 8.9 to 10.48N, the peel strength at 180°C is 12.7 to 15.64N, and the adhesion lasts for 22.3 to 24.5h.

[0132] It can be seen from Example 1 and Examples 4 to 7 that when the amount of the polymer emulsion thickener is the same, the isocyanate-modified acrylate monomer is not specific to the present invention, and the initial adhesion, peel strength and holding strength of the adhesive deteriorate; it can be seen from Example 1 and Examples 8 and 9 that when the amount of the polymer emulsion thickener is the same, the first acrylate monomer, the second acrylate monomer, the third acrylate monomer, and the fourth acrylate monomer are not in a specific mass ratio, and the initial adhesion, peel strength and holding strength of the adhesive deteriorate.

[0133] It can be seen from the comparison between Example 1 and the comparative example that when the amount of the polymer emulsion tackifier is the same, without using isocyanate to modify the acrylic ester monomer or without adding a functional group monomer, the performance of the adhesive is significantly deteriorated.

[0134] Comparison between Group 1 and Group 14 shows that the polymer emulsion tackifier provided by the present invention can achieve the effect of 15% aqueous rosin tackifier emulsion with a tackifier content of only 5%, and is better than aqueous rosin tackifier emulsion.

[0135] In summary, the polymer emulsion tackifier provided by the present invention modifies the acrylic acid ester monomer by using isocyanate, and at the same time, by adding acrylic acid monomers containing various functional groups in a specific ratio, the polymer emulsion tackifier can obtain a better adhesive performance improvement at a smaller addition amount compared with the conventional water-based rosin emulsion, effectively overcomes the disadvantages of poor compatibility between natural tackifying emulsion and acrylic acid emulsion, and unsatisfactory tackifying modification, can effectively replace the existing tackifying emulsion varieties, and achieve high-performance adhesive requirements. Therefore, the present invention has significant value in expanding the industrial application of acrylic acid ester adhesive emulsions.

[0136] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A polymer emulsion tackifier, characterized in that: The raw materials for preparing the polymer emulsion tackifier include a first acrylate monomer, a second acrylate monomer, a third acrylate monomer, a fourth acrylate monomer, an initiator and an emulsifier; The second acrylic acid ester monomer includes an isocyanate-modified acrylic acid ester monomer; The raw materials for preparing the isocyanate-modified acrylic ester monomer include hydroxyl-containing acrylic ester monomer, isocyanate and polymer polyol; The polymer polyol includes a polyether polyol; The isocyanate-modified acrylate monomer is prepared by the following method, which comprises: (i) reacting isocyanate with a hydroxyl-containing acrylic ester monomer to obtain a reactant 1; (ii) reacting the reactant 1 obtained in step (i) with a polymer polyol to obtain the isocyanate-modified acrylate monomer; The first acrylic acid ester monomer includes C2-C15 alkyl acrylate; The third acrylic acid ester monomer includes an acrylic acid ester monomer containing a hydroxyl group and / or an amino group; The fourth acrylic acid ester monomer includes a carboxyl-containing acrylic acid ester monomer; The mass ratio of the first acrylic ester monomer, the second acrylic ester monomer, the third acrylic ester monomer and the fourth acrylic ester monomer is 100:(30-50):(5-10):(10-20).

2. The polymer emulsion tackifier according to claim 1, characterized in that The isocyanate-modified acrylic ester monomer has a comb-shaped structure.

3. The polymer emulsion tackifier according to claim 1, characterized in that The molar ratio of the hydroxyl-containing acrylic ester monomer, isocyanate and polymer polyol is 1:(1-1.1):(1.1-1.2).

4. The polymer emulsion tackifier according to claim 1, characterized in that The hydroxyl-containing acrylic ester monomer includes at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate.

5. The polymer emulsion tackifier according to claim 4, characterized in that The hydroxyl-containing acrylic ester monomer is hydroxyethyl acrylate and / or hydroxypropyl acrylate.

6. The polymer emulsion tackifier according to claim 1, characterized in that The isocyanate includes diisocyanate.

7. The polymer emulsion tackifier according to claim 6, characterized in that The isocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate.

8. The polymer emulsion tackifier according to claim 7, characterized in that The isocyanate is hexamethylene diisocyanate and / or isophorone diisocyanate.

9. The polymer emulsion tackifier according to claim 1, characterized in that The number average molecular weight of the polymer polyol is 200-600.

10. The polymer emulsion tackifier according to claim 1, characterized in that The polyether polyol includes polyethylene glycol and / or polypropylene glycol.

11. The polymer emulsion tackifier according to claim 1, characterized in that The reaction in step (i) is carried out under a protective atmosphere.

12. The polymer emulsion tackifier according to claim 1, characterized in that The reaction system in step (i) also includes a catalyst and an inhibitor.

13. The polymer emulsion tackifier according to claim 12, characterized in that The content of the catalyst is 0.05-0.3% of the mass of the isocyanate.

14. The polymer emulsion tackifier according to claim 12, characterized in that The catalyst includes an organometallic catalyst.

15. The polymer emulsion tackifier according to claim 14, characterized in that The organic metal catalyst includes at least one of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dibutyrate or dioctyltin dilaurate.

16. The polymer emulsion tackifier according to claim 12, characterized in that: The content of the polymerization inhibitor is 0.05-0.15% of the mass of the hydroxyl-containing acrylic ester monomer.

17. The polymer emulsion tackifier according to claim 12, characterized in that: The polymerization inhibitor includes at least one of hydroquinone, p-benzoquinone, p-hydroxyanisole or tert-butylhydroquinone.

18. The polymer emulsion tackifier according to claim 1, characterized in that The reaction temperature in step (i) is 30-60°C.

19. The polymer emulsion tackifier according to claim 1, characterized in that The reaction time of step (i) is 1 to 3 hours.

20. The polymer emulsion tackifier according to claim 1, characterized in that The reaction temperature in step (ii) is 60-80°C.

21. The polymer emulsion tackifier according to claim 1, characterized in that The reaction time of step (ii) is 1 to 2 hours.

22. The polymer emulsion tackifier according to claim 1, characterized in that: The first acrylic acid ester monomer includes at least one of ethyl acrylate, butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate or lauric acrylate.

23. The polymer emulsion tackifier according to claim 22, characterized in that: The first acrylic ester monomer is butyl acrylate.

24. The polymer emulsion tackifier according to claim 1, characterized in that: The third acrylic acid ester monomer includes hydroxyethyl acrylate and / or hydroxypropyl acrylate.

25. The polymer emulsion tackifier according to claim 1, characterized in that: The carboxyl group-containing acrylic acid ester monomer includes β-acryloxy propionic acid and / or β-methacryloxy propionic acid.

26. The polymer emulsion tackifier according to claim 25, characterized in that The carboxyl-containing acrylic acid ester monomer is β-acryloxy propionic acid.

27. The polymer emulsion tackifier according to claim 1, characterized in that: The amount of the initiator used is 0.1-1% of the total weight of the monomers.

28. The polymer emulsion tackifier according to claim 1, characterized in that: The initiator includes at least one of a peroxide initiator, an azo initiator or a redox initiator.

29. The polymer emulsion tackifier according to claim 1, characterized in that The initiator includes at least one of potassium persulfate, ammonium persulfate, potassium persulfate-sodium sulfite, hydrogen peroxide or azobisisobutyramidine hydrochloride.

30. The polymer emulsion tackifier according to claim 1, characterized in that: The initiator is potassium persulfate and / or ammonium persulfate.

31. The polymer emulsion tackifier according to claim 1, characterized in that The content of the emulsifier is 0.2-1% of the total weight of the monomers.

32. The polymer emulsion tackifier according to claim 1, characterized in that The emulsifier includes anionic emulsifier and / or nonionic emulsifier.

33. The polymer emulsion tackifier according to claim 1, characterized in that The emulsifier includes at least one of alkylphenol polyoxyethylene ether, alkylphenol polyoxyethylene ether ammonium sulfate, ethoxylated alkyl sulfate sodium salt or polyoxyethylene ether castor oil ester.

34. The polymer emulsion tackifier according to claim 1, characterized in that The raw materials for preparing the polymer emulsion tackifier also include a chain transfer agent.

35. The polymer emulsion tackifier according to claim 34, characterized in that The amount of the chain transfer agent used is 0.5-3% of the total weight of the monomers.

36. The polymer emulsion tackifier according to claim 34, characterized in that The chain transfer agent includes a mercapto compound.

37. The polymer emulsion tackifier according to claim 34, characterized in that The chain transfer agent includes at least one of butyl mercaptan, tert-butyl mercaptan, dodecyl mercaptan, mercaptoethanol or mercaptopropionic acid.

38. The polymer emulsion tackifier according to claim 34, characterized in that The chain transfer agent is mercaptoethanol and / or mercaptopropionic acid.

39. A method for preparing a polymer tackifier according to any one of claims 1 to 38, characterized in that: The preparation method comprises: (1) mixing a first acrylic ester monomer, a second acrylic ester monomer, a third acrylic ester monomer, a fourth acrylic ester monomer, an emulsifier and a solvent, and pre-emulsifying the mixture to obtain a monomer pre-emulsion; (2) mixing 10 to 30% of the total mass of the monomer pre-emulsion obtained in step (1) with 30 to 50% of the initiator in the formula amount, and subjecting the mixture to polymerization reaction to obtain a seed emulsion; (3) The seed emulsion obtained in step (2) is mixed with the remaining monomer pre-emulsion and the remaining initiator to react to obtain the polymer emulsion thickener.

40. The preparation method according to claim 39, characterized in that: The mixed raw materials in step (1) also include a chain transfer agent.

41. The preparation method according to claim 39, characterized in that: The pre-emulsification method in step (1) includes shear emulsification.

42. The preparation method according to claim 41, characterized in that The shearing rotation speed is 300-800 r / min.

43. The preparation method according to claim 39, characterized in that: The temperature of the polymerization reaction in step (2) is 50-80°C.

44. The preparation method according to claim 39, characterized in that The polymerization reaction time in step (2) is 1 to 3 hours.

45. The preparation method according to claim 39, characterized in that: The mixing in step (3) includes sequentially dropping the remaining monomer pre-emulsion and the remaining initiator into the seed emulsion.

46. ​​The preparation method according to claim 45, characterized in that The remaining monomer pre-emulsion is added dropwise for 3 to 5 hours.

47. The preparation method according to claim 45, characterized in that The remaining initiator is added dropwise for 4 to 6 hours.

48. The preparation method according to claim 39, characterized in that: The reaction temperature in step (3) is 55-95°C.

49. The preparation method according to claim 39, characterized in that: The reaction time of step (3) is 2 to 5 hours.

50. The preparation method according to claim 39, characterized in that: The solid content of the polymer emulsion tackifier is 40-60%.

51. An acrylic adhesive, characterized in that: The acrylic adhesive comprises an acrylic masterbatch emulsion and a polymer emulsion tackifier as claimed in any one of claims 1 to 38.

52. The acrylic adhesive according to claim 51, characterized in that: The effective mass percentage of the polymer emulsion tackifier in the acrylic ester adhesive is 2-6%.

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