High-temperature-resistant, high-humidity-resistant and warping-resistant pressure-sensitive adhesive, adhesive tape and preparation method and application thereof

Abstract

The invention relates to a high-temperature-resistant, high-humidity-resistant and warping-resistant pressure-sensitive adhesive, an adhesive tape as well as a preparation method and application of the adhesive tape. The high-temperature-resistant, high-humidity-resistant and warping-resistant pressure-sensitive adhesive comprises a low-Tg acrylate copolymer component and a high-Tg acrylate copolymer component, the glass transition temperature of the low-Tg acrylate copolymer component is not higher than-30 DEG C; the acrylate copolymer component with high Tg has a cross-linked structure. The high-temperature-resistant and high-humidity-resistant warping-resistant pressure-sensitive adhesive has excellent adhesion and stripping force, especially excellent high-temperature-resistant and moisture-resistant performance, is suitable for adhesion and fixation of PC and aluminum materials, and can reduce the problems of warping and falling between the PC and the aluminum materials.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive, tape, its preparation method, and its application. Background Technology

[0002] Acrylic pressure-sensitive adhesives (PSAs) possess advantages such as good wetting properties and strong initial tack, making them widely used in labels, packaging tapes, and double-sided tapes. However, with the increasing reliability requirements of industries such as electronics and automotive manufacturing, especially in applications like mobile phone and tablet frame adhesives, more stringent requirements are being placed on the high-temperature and high-humidity resistance of PSAs. Under high-temperature environments, polymer chains are prone to thermal oxidative degradation, damaging the molecular structure of the PSA; simultaneously, moisture can penetrate into the adhesive layer and even the substrate interface, triggering corrosion or hydrolysis. These factors significantly shorten the lifespan of PSAs, making it difficult to meet market demands for material reliability and durability.

[0003] Polycarbonate (PC), a thermoplastic engineering plastic with excellent comprehensive properties, possesses high impact strength, good transparency, rigidity, flame retardancy, electrical insulation, and heat resistance, and is widely used in industrial fields such as consumer electronics. In many applications, pressure-sensitive adhesive tape is used to bond and fix PC to aluminum. However, PC's performance is unstable in high-temperature and high-humidity environments, and it is prone to hydrolysis, releasing carbon dioxide and water vapor, leading to problems such as warping and detachment of the bond between PC and aluminum.

[0004] Therefore, developing a pressure-sensitive adhesive tape that can maintain good adhesion under high humidity and high temperature conditions such as 85℃×85%RH and 60℃×90%RH, ensuring that the adhered object does not fall off or curl, presents both significant technical challenges and meets actual market demands. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the first objective of this invention is to provide a high-temperature and high-humidity resistant pressure-sensitive adhesive that has excellent adhesion and peel strength, especially excellent high-temperature and humidity resistance, and is suitable for bonding and fixing PC and aluminum materials, thereby reducing the problems of warping and detachment between PC and aluminum materials.

[0006] The second objective of this invention is to provide a method for preparing the high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive.

[0007] A third objective of this invention is to provide a high-temperature, high-humidity, anti-warping pressure-sensitive adhesive tape containing the high-temperature, high-humidity, anti-warping pressure-sensitive adhesive.

[0008] A fourth objective of this invention is to provide applications for the high-temperature, high-humidity, anti-warping pressure-sensitive adhesive or tape.

[0009] To achieve the first objective of this invention, this invention provides a high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive, comprising a low-Tg acrylate copolymer component and a high-Tg acrylate copolymer component; the glass transition temperature of the low-Tg acrylate copolymer component is not higher than -30°C; the high-Tg acrylate copolymer component has a crosslinked structure.

[0010] In some embodiments of the present invention, the glass transition temperature of the low Tg acrylate copolymer component is -60°C to -30°C.

[0011] In some embodiments of the present invention, the low Tg acrylate copolymer component is composed of first (meth)acrylic acid C1-C 18 It is obtained by polymerization of alkyl ester monomer, first acid-containing unsaturated monomer and hydroxyl-containing unsaturated monomer.

[0012] In some embodiments of the present invention, the first (meth)acrylic acid C1-C 18 The alkyl ester monomer is at least one of 2-ethylhexyl acrylate, n-butyl acrylate, methyl acrylate, and methyl methacrylate.

[0013] In some embodiments of the present invention, the first acid-containing unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid.

[0014] In some embodiments of the present invention, the hydroxyl-containing unsaturated monomer is at least one of hydroxyethyl methacrylate, hydroxybutyl methacrylate, and hydroxyhexyl methacrylate.

[0015] In some embodiments of the present invention, the low Tg acrylate copolymer component is obtained by solution polymerization.

[0016] In some embodiments of the present invention, the first (meth)acrylic acid C1-C 18 The mass ratio of the alkyl ester monomer, the first acidic unsaturated monomer, and the hydroxyl-containing unsaturated monomer is (360~370):32:(0.1~0.3).

[0017] In some embodiments of the present invention, the first (meth)acrylic acid C1-C 18 The alkyl ester monomer is a mixture of a first soft monomer and a first hard monomer, wherein the first soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate, and the first hard monomer is at least one of methyl acrylate and methyl methacrylate; the mass ratio of the first soft monomer to the first hard monomer is (267~348):(20~100).

[0018] In some embodiments of the present invention, the high Tg acrylate copolymer component is obtained by emulsion polymerization.

[0019] In some embodiments of the present invention, the glass transition temperature of the high Tg acrylate copolymer component is greater than 88°C.

[0020] In some embodiments of the present invention, the high Tg acrylate copolymer component is prepared by polymerization reaction of a mixture of macromolecular protective adhesive and monomers, and a multifunctional crosslinking agent.

[0021] In some embodiments of the present invention, the macromolecular protective colloid is composed of C1-C2 (meth)acrylic acid. 18 It is obtained by polymerization of alkyl ester monomers and second unsaturated monomers containing acidic groups; the second (meth)acrylic acid C1-C 18 The alkyl ester monomer is at least one of 2-ethylhexyl acrylate, n-butyl acrylate, methyl acrylate, and methyl methacrylate; the second acid-containing unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid; the weight-average molecular weight of the macromolecular protective adhesive is 8000 g / mol to 12000 g / mol.

[0022] In some embodiments of the present invention, the monomer mixture is a mixture of a high Tg monomer, a third acidic unsaturated monomer, and a basic unsaturated monomer. The high Tg monomer is at least one of methyl acrylate, methyl methacrylate, and isobornyl acrylate. The third acidic unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid. The basic unsaturated monomer is at least one of dimethylaminomethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, acrylamide, dimethylaminopropyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-benzylacrylamide, N-isopropylacrylamide, N-hydroxymethyl (meth)acrylamide, and N-tert-butylacrylamide.

[0023] In some embodiments of the present invention, the multifunctional crosslinking agent is at least one of dipropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,4-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, bis(trimethylolpropane)tetra(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, cyclohexanediethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polydipentaerythritol penta(meth)acrylate, and tris(2-acryloyloxyethyl)isocyanurate.

[0024] In some embodiments of the present invention, the mass ratio of the macromolecular protective adhesive, the monomer mixture and the multifunctional crosslinking agent is 30:(450~470):(3~6).

[0025] In some embodiments of the present invention, the second (meth)acrylic acid C1-C 18 The alkyl ester monomer is a mixture of a second soft monomer and a second hard monomer, wherein the second soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate, and the second hard monomer is at least one of methyl acrylate and methyl methacrylate; the mass ratio of the second soft monomer to the second hard monomer is (20~100):(650~800).

[0026] In some embodiments of the present invention, the second (meth)acrylic acid C1-C 18 The mass ratio of the alkyl ester monomer to the second acid-containing unsaturated monomer is (710~900):(100~290).

[0027] In some embodiments of the present invention, the mass ratio of the high Tg monomer, the third acid-containing unsaturated monomer, and the basic-containing unsaturated monomer is (450~460):(6~10):(4~5).

[0028] In some embodiments of the present invention, the high temperature and high humidity resistant anti-warping pressure-sensitive adhesive further includes a curing agent, wherein the amount of the curing agent is 0.2% to 1.0% of the total mass of the low Tg acrylate copolymer component and the high Tg acrylate copolymer component.

[0029] In some embodiments of the present invention, the mass ratio of the low-Tg acrylate copolymer component to the high-Tg acrylate copolymer component is 10:(1~3).

[0030] To achieve the second objective of this invention, this invention provides a method for preparing a high-temperature and high-humidity anti-warping pressure-sensitive adhesive as described in any of the above embodiments, comprising the following steps: Step 1: preparing a low-Tg acrylate copolymer component and a high-Tg acrylate copolymer component respectively; Step 2: mixing the low-Tg acrylate copolymer component and the high-Tg acrylate copolymer component evenly.

[0031] In some embodiments of the present invention, the preparation step of the low Tg acrylate copolymer component includes: adding a first (meth)acrylic acid C1-C to a reaction vessel. 18Alkyl ester monomer, first unsaturated monomer containing an acidic group, hydroxyl unsaturated monomer and solvent are purged with nitrogen at 23 ℃~50 ℃, the temperature is raised to 60 ℃~75 ℃, a free radical initiator is added, and the reaction is carried out for 2 h~4 h. Then a second free radical initiator is added, and the reaction is carried out for another 2 h~8 h until the monomer conversion is complete.

[0032] In some embodiments of the present invention, the preparation steps of the high Tg acrylate copolymer component include: mixing macromolecular protective colloid, water, and pH adjuster, stirring at a heating temperature until completely dissolved, with part of the dissolved macromolecular protective colloid located in a reaction vessel and the other part in an emulsification vessel; adding monomer mixture to the mixture in the emulsification vessel under stirring to obtain a pre-emulsion; adding a portion of the pre-emulsion to a crosslinking agent and mixing evenly; adding 7%~10% of the pre-emulsion to the reaction vessel, stirring evenly, and then adding a free radical initiator to obtain a seed emulsion; at 80℃~85℃, adding the pre-emulsion containing the crosslinking agent, the remaining pre-emulsion without the crosslinking agent, and the free radical initiator dropwise to the reaction vessel over 3~4 h, maintaining the temperature for 1h~2h after the addition is complete, lowering the temperature to 70℃, and then adding an oxidative-reduction initiator dropwise in parallel over 20min~30min, maintaining the temperature for 20min~30min; lowering the temperature to room temperature, adding a pH adjuster and a preservative, and filtering.

[0033] In some embodiments of the present invention, the preparation steps of the macromolecular protective adhesive include: adding C1-C second (meth)acrylic acid to a reaction vessel containing a solvent. 18 Alkyl ester monomer, second unsaturated monomer containing acidic group and free radical initiator are introduced into the reaction under nitrogen gas and reacted at 60 ℃~120 ℃ for 2 h~4 h. Then, a second free radical initiator is added and the reaction is continued for another 2~4 h until the monomer conversion is complete. The vacuum device is then turned on to remove the solvent and obtain a macromolecular protective gel.

[0034] In some embodiments of the present invention, the water is deionized water; the pH adjuster is at least one of ammonia, dimethylethanolamine, and triethanolamine; the free radical initiator is a thermal initiator, and is at least one of ammonium persulfate, sodium persulfate, and potassium persulfate; the redox initiator is at least one of ammonium persulfate-sodium bisulfite, ammonium persulfate-sodium metabisulfite, and tert-butyl hydroperoxide-sodium formaldehyde sulfoxylate; and the preservative is at least one of chloromethylisothiazolinone (CMI), methylisothiazolinone (MI), benzisothiazolinone (BIT), 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), and 2-methyl-4-isothiazolin-3-one (MIT).

[0035] In some embodiments of the present invention, step two includes: drying, dehydrating and granulating the emulsion of the high Tg acrylate copolymer component, dispersing the high Tg acrylate copolymer component evenly in a solvent, mixing and stirring it evenly with the low Tg acrylate copolymer component, adjusting the viscosity, and adding a curing agent to mix evenly.

[0036] To achieve the third objective of this invention, this invention provides a high-temperature and high-humidity anti-warping pressure-sensitive adhesive tape, comprising a substrate and a pressure-sensitive adhesive layer disposed on at least one side of the substrate, wherein the pressure-sensitive adhesive layer is made of the high-temperature and high-humidity anti-warping pressure-sensitive adhesive described in any of the above embodiments.

[0037] In some embodiments of the present invention, the substrate is at least one of PET, PE, PP, BOPP, PVC, and paper.

[0038] In some embodiments of the present invention, the substrate is subjected to double-sided corona treatment, with the power controlled at 2.0 kW to 3.0 kW.

[0039] In some embodiments of the present invention, the high temperature and high humidity anti-warping pressure-sensitive adhesive tape includes a release film, a first adhesive layer, the substrate, a foamed adhesive layer and a second adhesive layer stacked sequentially. The first adhesive layer and the second adhesive layer are made of the high temperature and high humidity anti-warping pressure-sensitive adhesive, and the foamed adhesive layer is obtained by adding foaming microparticles to the high temperature and high humidity anti-warping pressure-sensitive adhesive and then foaming it.

[0040] To achieve the fourth objective of this invention, this invention provides an adhesive composite material comprising a high-temperature and high-humidity anti-warping pressure-sensitive adhesive, PC, and aluminum material, wherein the high-temperature and high-humidity anti-warping pressure-sensitive adhesive bonds the PC and the aluminum material, and the high-temperature and high-humidity anti-warping pressure-sensitive adhesive is the high-temperature and high-humidity anti-warping pressure-sensitive adhesive or high-temperature and high-humidity anti-warping pressure-sensitive tape described in any of the above embodiments.

[0041] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0042] The high-temperature and high-humidity anti-warping pressure-sensitive adhesive provided by this invention comprises a low-Tg acrylate copolymer component and a high-Tg acrylate copolymer component. The low-Tg acrylate copolymer has a low glass transition temperature, while the high-Tg acrylate copolymer has a cross-linked structure. After compounding, the two components form a thin film on the substrate. The resulting pressure-sensitive tape after curing exhibits excellent adhesion and peel strength, especially high-temperature and high-humidity resistance. It demonstrates good adhesion and anti-warping effects under high temperature and high humidity conditions of 85℃×85%RH and 60℃×90%RH, making it suitable for bonding and fixing PC and aluminum materials, and reducing the problems of warping and detachment between PC and aluminum materials. Attached Figure Description

[0043] Figure 1This is a schematic diagram of the structure of an embodiment of the high temperature and high humidity resistant and anti-warping pressure-sensitive adhesive tape of the present invention.

[0044] In the diagram, 1-release film, 2-first adhesive layer, 3-PET substrate, 4-foaming adhesive layer, and 5-second adhesive layer.

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0046] The present invention provides a high temperature and high humidity resistant anti-warping pressure-sensitive adhesive, which is suitable for bonding and fixing PC and aluminum materials, and can also be used for bonding other objects, especially suitable for high temperature and high humidity application scenarios.

[0047] Specifically, the high-temperature and high-humidity anti-warping pressure-sensitive adhesive of this embodiment includes a low-Tg acrylate copolymer component and a high-Tg acrylate copolymer component. The glass transition temperature of the low-Tg acrylate copolymer component is no higher than -30°C, and the high-Tg acrylate copolymer component has a cross-linked structure. In the formulation of this embodiment, the low-Tg acrylate copolymer component is combined with the high-Tg acrylate copolymer component. The low-Tg acrylate copolymer component exhibits good high and low temperature resistance and adhesion, while the high-Tg acrylate copolymer component exhibits good temperature resistance and water resistance. The microphase separation of the two components can greatly improve the overall adhesion performance and significantly enhance the high-temperature and humidity resistance. It exhibits good adhesion and anti-warping effects under high temperature and high humidity conditions of 85°C × 85%RH and 60°C × 90%RH, making it suitable for bonding and fixing PC to aluminum materials, and reducing the problems of warping and detachment between PC and aluminum materials.

[0048] In some examples, the glass transition temperature of the low-Tg acrylate copolymer component is -60°C to -30°C, for example, -30°C, -32°C, -33°C, -35°C, -40°C, -42°C, -43°C, -45°C, -50°C, -55°C, -56°C, or -60°C. Tg can be estimated using the Fox formula.

[0049] In some examples, the low Tg acrylate copolymer component is composed of C1-C of the first (meth)acrylic acid. 18 It is obtained by polymerization of alkyl ester monomers, a first acid-containing unsaturated monomer, and a hydroxyl-containing unsaturated monomer. First (meth)acrylic acid C1-C 18The alkyl ester monomer can be at least one of 2-ethylhexyl acrylate, n-butyl acrylate, methyl acrylate, and methyl methacrylate; the first acid-containing unsaturated monomer can be at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid; and the hydroxyl-containing unsaturated monomer can be at least one of hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, and hydroxyhexyl (meth)acrylate. Using the above monomers can adjust the glass transition temperature of the acrylate copolymer and the adhesive properties of the pressure-sensitive adhesive.

[0050] In some examples, the low-Tg acrylate copolymer component is obtained by solution polymerization, which has advantages such as simple steps.

[0051] In some examples, the first (meth)acrylic acid C1-C 18 The mass ratio of the alkyl ester monomer, the first acidic unsaturated monomer, and the hydroxyl-containing unsaturated monomer is (360~370):32:(0.1~0.3), for example, it can be 367.8:32:0.2, to obtain good bonding properties.

[0052] In some examples, the first (meth)acrylic acid C1-C 18 The alkyl ester monomer is a mixture of a first soft monomer and a first hard monomer. The first soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate, and the first hard monomer is at least one of methyl acrylate and methyl methacrylate. The mass ratio of the first soft monomer to the first hard monomer is (267~348):(20~100), for example, it can be 347.8:20, 317.8:50, 267.8:100, etc., to obtain a lower Tg while maintaining good mechanical properties.

[0053] In some examples, the high-Tg acrylate copolymer component is obtained by emulsion polymerization. The high-Tg acrylate copolymer component is an acrylate with a cross-linked structure. When synthesized in an organic solvent, it is prone to phase separation, resulting in agglomeration and gelation. In this embodiment, the high-Tg acrylate copolymer component is obtained by emulsion polymerization, which can easily obtain a stable cross-linked network structure that is not easily separated from the low-Tg copolymer.

[0054] In some examples, the glass transition temperature of the high-Tg acrylate copolymer component is greater than 88°C to improve the high-temperature resistance and mechanical properties of the pressure-sensitive adhesive. Tg can be estimated according to the Fox formula.

[0055] In some examples, the high Tg acrylate copolymer component is prepared by polymerization of a macromolecular protective colloid and a monomer mixture, along with a multifunctional crosslinking agent. The macromolecular protective colloid can act as an emulsifier, avoiding the use of small molecule emulsifiers, thereby improving the water resistance of the pressure-sensitive adhesive.

[0056] In some examples, the macromolecular protective colloid is composed of C1-C di(meth)acrylic acid. 18 It is obtained by polymerization of alkyl ester monomers and second acid-containing unsaturated monomers; second (meth)acrylic acid C1-C 18 The alkyl ester monomer is at least one of 2-ethylhexyl acrylate, n-butyl acrylate, methyl acrylate, and methyl methacrylate; the second acid-containing unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid. The macromolecular protective adhesive prepared from the above raw materials can act as a macromolecular emulsifier. The macromolecular protective adhesive can participate in or not participate in the polymerization reaction of monomer mixtures and multifunctional crosslinking agents.

[0057] In some examples, the weight-average molecular weight of the macromolecular protective colloid is 8000 g / mol to 12000 g / mol, for example, it can be 8000 g / mol, 8500 g / mol, 8900 g / mol, 9000 g / mol, 9300 g / mol, 9400 g / mol, 9500 g / mol, 10000 g / mol, 10500 g / mol, 11000 g / mol, 11200 g / mol, 11300 g / mol, 11500 g / mol, or 12000 g / mol.

[0058] In some examples, the monomer mixture is a mixture of a high-Tg monomer, a third acidic unsaturated monomer, and a basic unsaturated monomer. The high-Tg monomer is at least one of methyl acrylate, methyl methacrylate, and isobornyl acrylate. The third acidic unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid. The basic unsaturated monomer is at least one of dimethylaminomethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, acrylamide, dimethylaminopropyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-benzylacrylamide, N-isopropylacrylamide, N-hydroxymethyl (meth)acrylamide, and N-tert-butylacrylamide. Using the above monomers can effectively improve Tg.

[0059] In some examples, the multifunctional crosslinking agent is at least one of dipropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,4-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, bis(trimethylolpropane)tetra(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, cyclohexanediethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polydipentaerythritol penta(meth)acrylate, and tris(2-acryloyloxyethyl)isocyanurate. The multifunctional crosslinking agent enables the copolymer to crosslink.

[0060] In some examples, the mass ratio of macromolecular protective colloid, monomer mixture and multifunctional crosslinking agent is 30:(450~470):(3~6), for example 30:463:5, to provide sufficient Tg and crosslinking degree.

[0061] In some examples, the second (meth)acrylic acid C1-C 18 The alkyl ester monomer is a mixture of a second soft monomer and a second hard monomer. The second soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate, and the second hard monomer is at least one of methyl acrylate and methyl methacrylate. The mass ratio of the second soft monomer to the second hard monomer is (20~100):(650~800) to obtain a higher Tg.

[0062] In some examples, the second (meth)acrylic acid C1-C 18 The mass ratio of the alkyl ester monomer to the second acid-containing unsaturated monomer is (710~900):(100~290).

[0063] In some examples, the mass ratio of high Tg monomer, third acidic unsaturated monomer and basic unsaturated monomer is (450~460):(6~10):(4~5), for example, it can be 451:8:4.

[0064] In some examples, the high-temperature and high-humidity anti-warping pressure-sensitive adhesive also includes a curing agent. The amount of curing agent is 0.2% to 1.0% of the total mass of the low-Tg acrylate copolymer component and the high-Tg acrylate copolymer component, and the degree of curing can be adjusted according to the actual mechanical performance requirements. The curing agent can be, for example, an isocyanate.

[0065] In some examples, the mass ratio of the low-Tg acrylate copolymer component to the high-Tg acrylate copolymer component is 10:(1~3), for example, 10:2.

[0066] In some examples, the preparation method of the high temperature and high humidity resistant anti-warping pressure-sensitive adhesive includes the following steps: Step 1: Prepare a low Tg acrylate copolymer component and a high Tg acrylate copolymer component separately; Step 2: Mix the low Tg acrylate copolymer component and the high Tg acrylate copolymer component evenly.

[0067] In some examples, the preparation steps of the low Tg acrylate copolymer component include: adding C1-C of (meth)acrylate to a reaction vessel. 18 Alkyl ester monomer, first unsaturated monomer containing an acidic group, hydroxyl unsaturated monomer and solvent are purged with nitrogen at 23 ℃~50 ℃, the temperature is raised to 60 ℃~75 ℃, a free radical initiator is added, and the reaction is carried out for 2 h~4 h. Then a second free radical initiator is added, and the reaction is carried out for another 2 h~8 h until the monomer conversion is complete.

[0068] In some examples, the preparation steps of the high Tg acrylate copolymer component include: mixing macromolecular protective colloid, water, and pH adjuster, stirring at a heating temperature until completely dissolved, with part of the dissolved macromolecular protective colloid in the reaction vessel and the other part in the emulsification vessel; adding monomer mixture to the mixture in the emulsification vessel under stirring to obtain a pre-emulsion; adding a portion of the pre-emulsion to a crosslinking agent and mixing evenly; adding 7%~10% of the pre-emulsion to the reaction vessel, stirring evenly, and then adding a free radical initiator to obtain a seed emulsion; at 80 ℃~85 ℃, adding the pre-emulsion containing the crosslinking agent, the remaining pre-emulsion without the crosslinking agent, and the free radical initiator dropwise to the reaction vessel over 3~4 h; after the dropwise addition is complete, maintaining the temperature for 1h~2 h, lowering the temperature to 70 ℃, and then adding an oxidative-reduction initiator dropwise in parallel for 20 min~30 min, maintaining the temperature for 20 min~30 min; lowering the temperature to room temperature, adding a pH adjuster and preservative, and filtering.

[0069] In some examples, the preparation steps of the macromolecular protective gel include: adding C1-C di(meth)acrylic acid to a reaction vessel containing a solvent. 18 Alkyl ester monomer, second unsaturated monomer containing acidic group and free radical initiator are purged with nitrogen gas and reacted at 60 ℃~120 ℃ for 2 h~4 h. Then, a second free radical initiator is added and the reaction is continued for another 2~4 h until the monomer conversion is complete. The vacuum device is then turned on to remove the solvent and obtain a macromolecular protective gel.

[0070] In some examples, the water is deionized water; the pH adjuster is at least one of ammonia, dimethylethanolamine, and triethanolamine; the free radical initiator is a thermal initiator, and is at least one of ammonium persulfate, sodium persulfate, and potassium persulfate; the redox initiator is at least one of ammonium persulfate-sodium bisulfite, ammonium persulfate-sodium metabisulfite, and tert-butyl hydroperoxide-sodium formaldehyde sulfoxylate; and the preservative is at least one of chloromethylisothiazolinone (CMI), methylisothiazolinone (MI), benzisothiazolinone (BIT), 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), and 2-methyl-4-isothiazolin-3-one (MIT).

[0071] In some examples, step two includes: drying, dehydrating and granulating the emulsion of the high Tg acrylate copolymer component, dispersing the high Tg acrylate copolymer component evenly in a solvent, mixing and stirring it evenly with the low Tg acrylate copolymer component, adjusting the viscosity, and adding a curing agent to mix evenly.

[0072] In some examples, the high temperature and high humidity resistant anti-warping pressure-sensitive adhesive tape includes a substrate and a pressure-sensitive adhesive layer disposed on at least one side of the substrate, the pressure-sensitive adhesive layer being made of the aforementioned high temperature and high humidity resistant anti-warping pressure-sensitive adhesive.

[0073] In some examples, the substrate is at least one of PET, PE, PP, BOPP, PVC, and paper, preferably PET. The PET substrate may undergo double-sided corona treatment with a controlled power of 2.0 kW to 3.0 kW.

[0074] In some examples, the high-temperature and high-humidity anti-warping pressure-sensitive adhesive tape comprises a release film, a first adhesive layer, a substrate, a foamed adhesive layer, and a second adhesive layer, which are sequentially stacked. The first and second adhesive layers are made of high-temperature and high-humidity anti-warping pressure-sensitive adhesive, and the foamed adhesive layer is obtained by adding foaming microparticles to the high-temperature and high-humidity anti-warping pressure-sensitive adhesive and then foaming it. The total thickness of the first adhesive layer, substrate, foamed adhesive layer, and second adhesive layer is 150~350μm.

[0075] In some examples, the preparation method of high temperature and high humidity resistant anti-warping pressure sensitive tape includes: (1) double-sided corona treatment of PET substrate, adjusting the voltage and controlling the power at 2.0 ~ 3.0 KW to prevent PET from being broken down. After the high Tg acrylate copolymer is dried by dehydration, it is dissolved in solvent EtOAc and mixed with low Tg acrylate copolymer according to the solid content, stirred evenly, and the foamed microspheres are diluted with solvent. Then, solvent EtOAc is added to adjust the viscosity to 2000 ~ 3000 mPas, 0.2 ~ 1.0% curing agent L 75 is added, and the mixture is allowed to stand to defoam. The crosslinking density is adjusted by the gradient change of the amount of curing agent. (2) Foaming process: After the glue has completely eliminated air bubbles, apply the glue to the release film with a thickness of 60-80 μm. Evaporate the solvent in an oven at 120℃ for 2-3 minutes, then place it in a high-temperature oven at 150-160℃ for 2-3 minutes for foaming. Then, laminate it onto the corona-treated PET substrate. (3) Topcoat coating process: Apply a 70-100 μm topcoat using the release film, laminate it onto the corona-treated PET substrate, and roll it up. The topcoat is glue without foamed microspheres. Apply another 70-100 μm topcoat using the release film, laminate it onto the foam surface. The highest drying temperature for the topcoat is 120℃, and the drying time is 3 minutes. Roll up the product and cure it in a 60℃ oven for 48 hours.

[0076] The technical solution of the present invention will be further described below through specific embodiments. The embodiments described in this invention are only illustrative examples of the present invention and do not limit the scope of the present invention.

[0077] The raw materials used in the following examples and comparative examples are shown in Table 1 below.

[0078] Table 1 Raw materials used in the examples and comparative examples

[0079]

[0080] I. Preparation of Low Tg Polymer-Based Adhesives

[0081] Basic adhesive L1

[0082] In a 1-liter glass reactor, 347.8 g EHA, 20 g MA, 0.2 g HEA, 32 g AA, and 600 g EtOAc were added sequentially. After purging with nitrogen for 45 minutes, the temperature was raised to 58°C. o C, and add 0.4 g AIBN, and adjust the outside water bath temperature to 62°C. o At temperature C, the reaction was carried out at a constant temperature. After polymerization for 4 hours, 0.4 g of AIBN was added. After reaction for 6 hours, 0.2 g of ABVN was added, and after polymerization for 2 hours, the reaction was stopped, and the temperature was lowered to room temperature to obtain adhesive L1.

[0083] Basic adhesive L2

[0084] In a 1-liter glass reactor, 187.8 g EHA, 160 g nBA, 20 g MA, 0.2 g HEA, 32 g AA, and 600 g EtOAc were added sequentially. After purging with nitrogen for 45 minutes, the temperature was raised to 58°C. o At temperature C, 0.1 g of ABVN was added, and the reaction was carried out at this temperature for 3 hours; then 0.4 g of AIBN was added, and the external water bath temperature was adjusted to 62°C. o At temperature C, the reaction was carried out at a constant temperature. After polymerization for 4 hours, 0.4 g of AIBN was added. After another 4 hours of reaction, 0.2 g of ABVN was added, and after another 2 hours of polymerization, the reaction was stopped, and the temperature was lowered to room temperature to obtain adhesive L2.

[0085] Base adhesive L3

[0086] In a 1-liter glass reactor, 77.8 g EHA, 240 g nBA, 50 g MA, 0.2 g HEA, 32 g AA, and 600 g EtOAc were added sequentially. After purging with nitrogen for 45 minutes, the temperature was raised to 58°C. o At temperature C, 0.12 g of ABVN was added, and the reaction was carried out at this temperature for 3 h; then 0.4 g of AIBN was added, and the external water bath temperature was adjusted to 62°C. o At temperature C, the reaction was carried out at a constant temperature. After polymerization for 4 h, 0.4 g of AIBN was added. After reacting at 70°C for 4 h, the temperature was lowered to room temperature to obtain adhesive L3.

[0087] Base adhesive L4

[0088] In a 1-liter glass reactor, 267.8 g nBA, 100 g MA, 0.2 g HEA, 32 g AA, and 600 g EtOAc were added sequentially. After purging with nitrogen for 45 minutes, the temperature was raised to 58°C. o C. Add 0.4 g AIBN and adjust the external water bath temperature to 62°C. o At temperature C, the reaction was carried out at a constant temperature. After polymerization for 4 hours, 0.4 g of AIBN was added. After another 4 hours of reaction, 0.2 g of ABVN was added, and after polymerization for 2 hours, the temperature was lowered to room temperature to obtain adhesive L4.

[0089] Table 2 Formulations for synthesizing low Tg polymer base adhesives

[0090]

[0091] II. Preparation of Protective Adhesive

[0092] Protective adhesive P1

[0093] Add 900 g of toluene to a glass reactor. In another reactor, add 100 g of AA, 800 g of MMA, 100 g of EHA, and 12 g of BPO sequentially. Purge with nitrogen for 45 min while stirring, and heat to reflux. After adding the mixed monomers dropwise over 3 h, rinse the reactor and piping with 20 g of toluene, and reflux for 2 h. Dissolve 2 g of BPO in 30 g of toluene, add dropwise over 15 min, and reflux for 2 h. Dissolve another 2 g of BPO in 20 g of toluene, add dropwise over 15 min, rinse the piping with 14 g of toluene, reflux for 2 h, then connect a vacuum device to remove the solvent, and transfer to the macromolecular protective colloid P1.

[0094] Protective adhesive P2

[0095] Add 900 g of sec-butyl acetate to a glass reactor. In another reactor, add 180 g of AA, 800 g of MMA, 20 g of EHA, and 12 g of BPO sequentially. Purge with nitrogen for 45 min while stirring, and heat to reflux. After adding the mixed monomers dropwise over 3 h, rinse the reactor and piping with 20 g of sec-butyl acetate and reflux for 2 h. Dissolve 2 g of BPO in 30 g of sec-butyl acetate and add dropwise over 15 min, then reflux for 2 h. Dissolve 2 g of DTBP in 20 g of butyl acetate and add dropwise over 15 min. Rinse the piping with 14 g of sec-butyl acetate, reflux for 2 h, then connect the vacuum device to remove the solvent, and proceed to the macromolecular protective colloid P2.

[0096] Protective adhesive P3

[0097] Add 600 g of sec-butyl acetate and 300 g of butyl acetate to a glass reactor. In another reactor, add 290 g of AA, 650 g of MMA, 60 g of nBA, and 12 g of BPO sequentially. Purge with nitrogen for 45 min while stirring, and heat to reflux. After adding the mixed monomers dropwise over 3 h, rinse the reactor and pipelines with 20 g of sec-butyl acetate and reflux for 2 h. Dissolve 2 g of DTBP in 30 g of butyl acetate and add dropwise over 15 min, then reflux for 2 h. Dissolve another 2 g of DTBP in 20 g of butyl acetate and add dropwise over 15 min. Rinse the pipeline with 14 g of butyl acetate, reflux for 2 h, then connect the vacuum device to remove the solvent, and transfer to macromolecular protective colloid P3.

[0098] Table 3 Formulations of Synthetic Macromolecular Protective Gel

[0099]

[0100] III. Preparation of High Tg Tackifying Resins

[0101] Tackifying resin H1

[0102] In the reaction vessel, 190 g of water, 15 g of macromolecular protective colloid P1, and 2 g of DMEA were added sequentially. 85 o Stir at C until completely dissolved, and use as the base mixture for the reactor.

[0103] Add 254 g of water, 15 g of macromolecular protective colloid P1, and 2 g of DMEA sequentially to a pre-emulsification vessel. o Stir at C until dissolved, cool down, then add 451 g MMA, 4 g AM, and 8 g AA in sequence, and emulsify at high speed for 30 min to obtain a pre-emulsion.

[0104] Divide the preemulsion into two portions. Add 5 g of DPGDA to the first portion and stir at high speed until homogeneous. Add 7% of the preemulsion dropwise to the reactor, stir until homogeneous, and then heat under nitrogen protection at 83-85°C. o Seed emulsion was prepared by adding 0.8 g of APS initiator dissolved in 10 g of water dropwise at C.

[0105] The pre-emulsion with added cross-linking agent was added dropwise over 2 hours, followed by the addition of the pre-emulsion without cross-linking agent over another 2 hours; a 1.2 g APS initiator solution dissolved in 30 g water was added dropwise over 4 hours; after the addition was complete, 85 o Keep warm at 70°C for 1 hour. Then cool down to 70°C. o C. Dissolve 1 g TBHP in 5 g water and 0.8 g sodium formaldehyde sulfoxylate in 5 g water. Add the redox initiator dropwise in parallel through two dropping funnels over 25-30 minutes. After maintaining the temperature for 30 minutes, cool to room temperature, adjust the pH to 7.5-8.0 with ammonia, add the preservative CMI, test and adjust the solid content, and filter to obtain the inner cross-linked high Tg polymer H1.

[0106] Tackifying resin H2

[0107] In the reactor, 190 g of water, 15 g of macromolecular protective colloid P2 and 2 g of DMEA were added in sequence and stirred at 85°C until completely dissolved, which served as the base mixture for the reactor.

[0108] Add 254 g of water, 15 g of macromolecular protective colloid P2, and 2 g of DMEA sequentially to a pre-emulsification vessel. o Stir until dissolved, cool, then add 451 g IBOA, 4 g AM, and 8 g AA in sequence, and emulsify at high speed for 30 min to obtain a pre-emulsion.

[0109] Divide the preemulsion into two portions. Add 5 g of TMPTA to the first portion and stir at high speed until homogeneous. Add 7% of the preemulsion dropwise to the reactor, stir until homogeneous, and then heat under nitrogen protection at 83-85°C. o Seed emulsion was prepared by adding 0.8 g of APS initiator dissolved in 10 g of water dropwise at C.

[0110] Add the pre-emulsion with cross-linking agent dropwise over 2 hours, then add the other half of the pre-emulsion without cross-linking agent dropwise over 2 hours; add 1.2 g of APS initiator solution in 30 g of water dropwise over 4 hours; after the addition is complete, 85 o Keep warm at C for 1 hour. Cool down by 70 degrees. o At C, within 25 to 30 minutes, ammonium persulfate solution-sodium bisulfite solution were added dropwise in parallel through two dropping funnels. After keeping warm for 30 minutes, the mixture was cooled to room temperature. The pH value was adjusted to 7.5 to 8.0 with ammonia water. The preservative BIT was added to the tank. The solid content was tested and adjusted. The mixture was then filtered to obtain the inner cross-linked high Tg polymer H2.

[0111] Tackifying resin H3

[0112] In the reaction vessel, 190 g of water, 15 g of macromolecular protective colloid P3, and 2 g of DMEA were added sequentially. 85 o Stir at C until completely dissolved, and use as the base mixture for the reactor.

[0113] Add 254 g of water, 15 g of macromolecular protective colloid P2, and 2 g of DMEA sequentially to a pre-emulsification vessel, and heat for 60°C. o After dissolving at C, and cooling down, add 200 g MMA, 251 g IBOA, 4 g AM, and 8 g AA in sequence, and emulsify at high speed for 30 min to obtain a pre-emulsion.

[0114] Divide the preemulsion into two portions. Add 5 g of PPTTA to the first portion and stir at high speed until homogeneous. Add 8% of the preemulsion dropwise to the reactor, stir until homogeneous, and then heat under nitrogen protection at 83-85°C. o Seed emulsion was prepared by adding 0.8 g of APS initiator dissolved in 10 g of water dropwise at C.

[0115] Add the pre-emulsion with added cross-linking agent dropwise over 2 hours; add the other half of the pre-emulsion without cross-linking agent dropwise over 2 hours; add 1.2 g of APS initiator solution in 30 g of water dropwise over 4 hours; after the addition is complete, 85 o Keep warm at 70°C for 1 hour. Then cool down to 70°C. oAt C, ammonium persulfate solution-sodium metabisulfite solution were added dropwise in parallel through two dropping funnels within 25-30 minutes. After keeping warm for 30 minutes, the mixture was cooled to room temperature. The pH value was adjusted to 7.5-8.0 with ammonia water. Preservative MI was added to the tank. The solid content was tested and adjusted. The mixture was then filtered to obtain the inner cross-linked high Tg polymer H3.

[0116] Table 4 Formulations for synthesizing high Tg tackifying resins

[0117]

[0118] Comparative Tackifying Resin C1

[0119] In the reaction vessel, 190 g of water, 15 g of macromolecular protective colloid P3, and 2 g of DMEA were added sequentially. 85 o Stir at C until completely dissolved, and use as the base mixture for the reactor.

[0120] Add 254 g of water, 15 g of macromolecular protective colloid P2, and 2 g of DMEA sequentially to a pre-emulsification vessel, and heat for 60°C. o After dissolving at C, and cooling down, add 200 g MMA, 251 g IBOA, 4 g AM, and 8 g AA in sequence, and emulsify at high speed for 30 min to obtain a pre-emulsion.

[0121] Add 4% of the pre-emulsion dropwise to the reactor, stir until homogeneous, and then heat under nitrogen protection at 83-85°C. o Seed emulsion was prepared by adding 0.8 g of APS initiator dissolved in 10 g of water dropwise at C.

[0122] Add the pre-emulsion and an initiator solution of 1.2 g APS dissolved in 30 g water dropwise over 4 hours; after the addition is complete, 85 o Keep warm at 70°C for 1 hour. Then cool down to 70°C. o At C, tert-butyl hydrogen peroxide solution-sodium formaldehyde sulfoxylate solution were added dropwise in parallel through two dropping funnels within 25-30 minutes. After keeping warm for 30 minutes, the solution was cooled to room temperature, and the pH value was adjusted to 7.5-8.0 with ammonia. The preservative MIT was added to the tank, and the product was filtered to obtain high Tg polymer C1.

[0123] Comparative tackifying resin C2

[0124] In the reaction vessel, add 190 g of water, 10 g of Dowfax 2A1, and 85 g of [unclear - possibly a specific chemical or chemical formula] in sequence. o Stir at C until completely dissolved, and use as the base mixture for the reactor.

[0125] Add 254 g of water, 15 g of Dowfax 2A1, and 2 g of DMEA sequentially to a pre-emulsification vessel, and heat for 60°C.o After dissolving at C, and cooling down, add 200 g MMA, 251 g IBOA, 4 g AM, and 8 g AA in sequence, and emulsify at high speed for 30 min to obtain a pre-emulsion.

[0126] Divide the preemulsion into two portions. Add 5 g of TMPTA to the first portion and stir at high speed until homogeneous. Add 8% of the preemulsion dropwise to the reactor, stir until homogeneous, and then heat under nitrogen protection at 83-85°C. o Seed emulsion was prepared by adding 0.8 g of APS initiator dissolved in 10 g of water dropwise at C.

[0127] Add the pre-emulsion containing the cross-linking agent dropwise over 2 hours, and then add the other half of the pre-emulsion without the cross-linking agent dropwise over 2 hours. Simultaneously, add 1.2 g of APS initiator solution in 30 g of water dropwise over 4 hours; after the addition is complete, at 85°C... o Keep warm at 70°C for 1 hour. Then cool down to 70°C. o C, ammonium persulfate solution-sodium metabisulfite solution were added dropwise in parallel through two dropping funnels within 25-30 minutes. After keeping warm for 30 minutes, the mixture was cooled to room temperature, and the pH value was adjusted to 7.5-8.0 with ammonia water. The preservative CMIT was added to the tank, and the mixture was filtered to obtain high Tg polymer C2.

[0128] Comparative tackifying resin C3

[0129] In the reaction vessel, add 190 g of water, 2 g of SR-10, and 85 g of [unclear - possibly a specific ingredient or compound] in sequence. o Stir at C until completely dissolved, and use as the base mixture for the reactor.

[0130] 254 g of water and 10 SR-10 were added sequentially to a pre-emulsification vessel and dispersed at high speed until completely dissolved. Then, 200 g of MMA, 251 g of IBOA, 4 g of AM, and 8 g of AA were added sequentially and emulsified at high speed for 30 min to obtain a pre-emulsion.

[0131] Divide the preemulsion into two portions. Add 5 g of PTTTA to the first portion and stir at high speed until homogeneous. Add 8% of the preemulsion dropwise to the reactor, stir until homogeneous, and then heat under nitrogen protection at 83-85°C. o Seed emulsion was prepared by adding 0.8 g of APS initiator dissolved in 10 g of water dropwise at C.

[0132] Add the pre-emulsion containing the cross-linking agent dropwise over 2 hours, and then add the other half of the pre-emulsion without the cross-linking agent dropwise over 2 hours. Simultaneously, add 1.2 g of APS initiator solution in 30 g of water dropwise over 4 hours; after the addition is complete, at 85°C... o Keep warm at 70°C for 1 hour. Then cool down to 70°C. oC, ammonium persulfate solution-sodium metabisulfite solution were added dropwise in parallel through two dropping funnels within 25-30 minutes. After keeping warm for 30 minutes, the mixture was cooled to room temperature, and the pH value was adjusted to 7.5-8.0 with ammonia water. The preservative CMIT was added to the tank, and the mixture was filtered to obtain high Tg polymer C3.

[0133] Table 5 Raw materials for the comparative examples of synthesized tackifying resins

[0134]

[0135] IV. Preparation of High Temperature and High Humidity Resistant Anti-Warping Pressure-Sensitive Adhesive Tape

[0136] The low-Tg polymer base adhesive and high-Tg tackifying resin synthesized above were used to prepare an adhesive tape. The resulting high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive tape has the following structure: Figure 1 As shown.

[0137] Double-sided corona treatment was performed on a 25 μm thick PET substrate 3, with the voltage adjusted and the power controlled at 2.5 KW. The high-Tg acrylate copolymer was dried after dehydration and dissolved in EtOAc solvent. It was then mixed with the low-Tg acrylate copolymer at a solids ratio of 10:2 and stirred thoroughly. Foaming microspheres diluted with solvent (3% addition) were added, and EtOAc was added again to adjust the viscosity to approximately 2500 mPas. 0.6% of curing agent L75 was added, and the mixture was allowed to stand to defoam, yielding a foamed adhesive. The high-Tg acrylate copolymer was dried after dehydration and dissolved in EtOAc solvent. It was then mixed with the low-Tg acrylate copolymer at a solids ratio of 10:2 and stirred thoroughly. EtOAc was added again to adjust the viscosity to approximately 2500 mPas, and 0.6% of curing agent L75 was added. The mixture was allowed to stand to defoam, yielding a surface adhesive.

[0138] Foaming process: After the foaming adhesive has completely eliminated the air bubbles, the adhesive is applied to the release film. The solvent is evaporated in an oven at 120°C for 3 minutes, and then it is placed in a high-temperature oven at 160°C for 3 minutes to foam, resulting in foamed adhesive layer 4. Then, the foamed adhesive layer 4 is laminated with a corona-treated PET substrate 3.

[0139] Topcoat application process: Apply the first layer of topcoat using a separate release film 1, and laminate it onto the corona-treated PET substrate. Then apply the second layer of topcoat using another release film, and laminate it onto the foam surface of the expanded foam layer 4 after removing the release film. The highest drying temperature range for the topcoat is 120℃, and the drying time is 3 minutes. After winding the product, cure it in a 60℃ oven for 48 hours. The first layer of topcoat forms the first topcoat layer 2, and the second layer of topcoat forms the second topcoat layer 5. The coating thickness of each layer of topcoat is the same as the coating thickness of the expanded foam adhesive.

[0140] The resulting tape is formed by sequentially stacking release film 1, first adhesive layer 2, PET substrate 3, foamed adhesive layer 4, and second adhesive layer 5, wherein the total thickness of the first adhesive layer 2, PET substrate 3, foamed adhesive layer 4, and second adhesive layer 5 is the usable thickness of the tape.

[0141] Test methods

[0142] 1. Peel strength test: Referring to GB / T 2792-2014 Test method for 180° peel strength of pressure sensitive adhesive tape, under standard laboratory conditions, a 25 mm wide double-sided adhesive tape (material SUS304, surface roughness 0.05 μm) was pasted onto a steel plate. After pasting, the release material on the back was removed, and a 0.05 mm thick PET film was pasted onto the back adhesive layer. A 2 kg pressure roller was used to roll it back and forth 3 times. After standing for 20 min, the 180° peel strength was tested at a test speed of 300 mm / min.

[0143] 2. Holding Force Test at 70℃: Referring to GB / T 4851-2014 "Test Method for Adhesive Tape Holding Force", the sample was cut into strips 25 mm wide and approximately 150 mm long, reinforced with 50 μm PET. The surface of a 304 stainless steel plate was cleaned with ethyl acetate. The tape was then smoothly applied to the steel plate, with a bonding area of ​​25 mm in length and 25 mm in width. A 2 kg roller was used to press the tape back and forth three times, with a wetting time of 20 min. The steel plate was then hung on a holding force testing machine with a 1 kg weight. The machine temperature was set to 70 ± 2℃. The timing automatically stopped after the sample fell, and the time recorded was the holding force test data.

[0144] 3. Anti-warping test:

[0145] 3.1 Test sample dimensions and material composition:

[0146] The tape size is 20 mm × 150 mm; the test plate is made of 5052 anodized aluminum with a surface roughness of 0.15 μm and a size of 20 mm × 150 mm × 0.5 mm; the material is PC with a smooth surface and a size of 25 mm × 200 mm × 2 mm.

[0147] 3.2 Test Procedure:

[0148] Clean the aluminum sheet and PC board with a lint-free cloth dampened with anhydrous ethanol, and then wipe them dry with a dry and clean lint-free cloth. After cleaning, do not touch the working surface of the aluminum sheet and board with your hands or other objects.

[0149] Attach the aluminum sheet to the double-sided tape, and use a blade to cut the tape to the size of the aluminum sheet around its perimeter. Attach the other side of the double-sided tape to the PC board, with the aluminum sheet placed in the middle of the PC board.

[0150] The roller was used to press the material back and forth three times at a speed of 120 mm / s using a 2 kg roller, and then left to stand for 2 hours. The ambient temperature during this standing period was 23 ± 2 ℃, and the relative humidity was 50 ± 5%.

[0151] The fitted sample is bent into a 193 mm long groove to give the sample a certain curvature.

[0152] 3.3 Warping Resistance Test

[0153] 70℃ environment: The long groove containing the sample was placed in a 70℃ test oven, and the height of the warping at both ends of the aluminum plate was measured after 24 hours.

[0154] 60℃×90%RH environment: The long trough containing the sample was placed in a 60℃ / 90%RH test oven, and the height of the warping at both ends of the aluminum plate was measured after 24 hours.

[0155] 85℃×85%RH: The entire long trough containing the sample was placed in a test oven at 85℃ / 85%RH. After 24 hours, the height of the warping at both ends of the aluminum plate was measured.

[0156] The test results are shown in Table 6 below.

[0157] Table 6 Test Results

[0158]

[0159] As shown in the table, in Examples 1 to 4, the holding power at 70°C can exceed 10,000 min through the combination of base adhesives L1-L4 and tackifying resins H1-H3. When the thickness of the pressure-sensitive adhesive layer is 150 μm, the 180° peel strength of the foam side is 15.2 N / 25 mm, 18.6 N / 25 mm, 19.0 N / 25 mm and 18.5 N / 25 mm, respectively, while the 180° peel strength of the PET side is 14.3 N / 25 mm, 18.5 N / 25 mm, 18.7 N / 25 mm and 18.1 N / 25 mm, respectively. The peel strength of the two sides of the double-sided adhesive resin is relatively close. When the thickness increases to 250 μm, the 180° peel force of the foam surface increases significantly. In Example 5, the 180° peel force of the foam surface is 36.2 N / 25 mm, and the 180° peel force of the PET layer is 34.5 N / 25 mm. In Example 6, when the layer thickness is further increased to 350 μm, the 180° peel force of the foam surface is 40.5 N / 25 mm, and the 180° peel force of the PET layer is 33.6 N / 25 mm. The peel force of the foam layer significantly exceeds that of the PET layer.

[0160] In Examples 1 to 6, the holding power at 70 °C all exceeded 10,000 min, indicating that a reasonable combination of base adhesive, high Tg tackifying resin and curing agent can achieve excellent holding power.

[0161] In Examples 1 to 4, the anti-warping height at 70℃ is approximately zero, while slight warping occurs at 60℃ and 90%RH and 85℃ and 85%RH. For example, in Example 1, the height increases to 2mm at 60℃ and 90%RH, and further increases to 3mm at 85℃ and 85%RH. In Examples 5 and 6, the layer thickness is increased to 250 μm and 350 μm respectively, and the anti-warping height is zero under all three conditions. This indicates that under the same conditions, the anti-warping height increases with harsher environments; increasing the layer thickness is beneficial for improving anti-warping performance.

[0162] In Examples 7 to 9, the peel force exhibited the same pattern as the layer thickness increased. In Example 7, the peel forces on both sides of the double-sided adhesive were relatively close. In Examples 8 and 9, when the thickness was 250 μm and 350 μm, the peel force of the foam layer was higher than that of the PET layer.

[0163] In Examples 7 to 9, the anti-warping height at 70°C was 4, 3, and 4 mm, respectively, which was significantly increased compared to Examples 4 to 6 with the same thickness; the anti-warping height at 60°C and 90%RH and at 85°C and 85%RH was further increased to 6 to 7 mm.

[0164] As can be seen from the above, this invention first synthesizes a solution-type low-Tg acrylate copolymer and an emulsion-type high-Tg acrylate crosslinking copolymer. After the emulsion is dried, dehydrated, and granulated, the high-Tg copolymer is uniformly dispersed in a solvent, then mixed and stirred evenly with the low-Tg copolymer. After adding a curing agent, a thin film is formed on the substrate. The pressure-sensitive tape obtained after curing has excellent adhesion and peel strength, and exhibits excellent high-temperature and moisture resistance in the bonding of PC and aluminum.

[0165] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive, characterized in that... It includes a low-Tg acrylate copolymer component and a high-Tg acrylate copolymer component; the glass transition temperature of the low-Tg acrylate copolymer component is not higher than -30°C; the high-Tg acrylate copolymer component has a cross-linked structure.

2. The high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive according to claim 1, characterized in that... The glass transition temperature of the low Tg acrylate copolymer component is -60℃ to -30℃. The low-Tg acrylate copolymer component is composed of C1-C1 (meth)acrylic acid. 18 It is obtained by polymerization of alkyl ester monomer, first unsaturated monomer containing an acidic group, and hydroxyl-containing unsaturated monomer; The first (meth)acrylic acid C1-C 18 The alkyl ester monomer is at least one of 2-ethylhexyl acrylate, n-butyl acrylate, methyl acrylate, and methyl methacrylate; The first acid-containing unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid; The hydroxyl-containing unsaturated monomer is at least one of hydroxyethyl methacrylate, hydroxybutyl methacrylate, and hydroxyhexyl methacrylate.

3. The high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive according to claim 2, characterized in that... The low-Tg acrylate copolymer component was obtained by solution polymerization; The first (meth)acrylic acid C1-C 18 The mass ratio of the alkyl ester monomer, the first acid-containing unsaturated monomer, and the hydroxyl-containing unsaturated monomer is (360~370):32:(0.1~0.3). The first (meth)acrylic acid C1-C 18 The alkyl ester monomer is a mixture of a first soft monomer and a first hard monomer, wherein the first soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate, and the first hard monomer is at least one of methyl acrylate and methyl methacrylate; the mass ratio of the first soft monomer to the first hard monomer is (267~348):(20~100).

4. A high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive according to any one of claims 1 to 3, characterized in that... The high-Tg acrylate copolymer component was obtained by emulsion polymerization; The glass transition temperature of the high Tg acrylate copolymer component is greater than 88°C. The high Tg acrylate copolymer component is prepared by polymerization reaction of macromolecular protective colloid, monomer mixture, and multifunctional crosslinking agent; The macromolecular protective colloid is composed of C1-C di(meth)acrylic acid. 18 It is obtained by polymerization of alkyl ester monomers and second unsaturated monomers containing acidic groups; the second (meth)acrylic acid C1-C 18 The alkyl ester monomer is at least one of 2-ethylhexyl acrylate, n-butyl acrylate, methyl acrylate, and methyl methacrylate; the second acid-containing unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid; the weight-average molecular weight of the macromolecular protective adhesive is 8000 g / mol to 12000 g / mol. The monomer mixture is a mixture of a high Tg monomer, a third acidic unsaturated monomer, and a basic unsaturated monomer. The high Tg monomer is at least one of methyl acrylate, methyl methacrylate, and isobornyl acrylate. The third acidic unsaturated monomer is at least one of (meth)acrylic acid, dimethacrylic acid, fumaric acid, and itaconic acid. The basic unsaturated monomer is at least one of dimethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, acrylamide, dimethylaminopropyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-benzylacrylamide, N-isopropylacrylamide, N-hydroxymethyl (meth)acrylamide, and N-tert-butylacrylamide. The multifunctional crosslinking agent is at least one of the following: dipropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,4-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, bis(trimethylolpropane)tetra(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, cyclohexanediethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polydipentaerythritol penta(meth)acrylate, and tris(2-acryloyloxyethyl)isocyanurate.

5. The high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive according to claim 4, characterized in that... The mass ratio of the macromolecular protective colloid, the monomer mixture, and the multifunctional crosslinking agent is 30:(450~470):(3~6); The second (meth)acrylic acid C1-C 18 The alkyl ester monomer is a mixture of a second soft monomer and a second hard monomer, wherein the second soft monomer is at least one of 2-ethylhexyl acrylate and n-butyl acrylate, and the second hard monomer is at least one of methyl acrylate and methyl methacrylate; the mass ratio of the second soft monomer to the second hard monomer is (20~100):(650~800). The second (meth)acrylic acid C1-C 18 The mass ratio of the alkyl ester monomer to the second acid-containing unsaturated monomer is (710~900):(100~290). The mass ratio of the high Tg monomer, the third acid-containing unsaturated monomer, and the basic-containing unsaturated monomer is (450~460):(6~10):(4~5). The high-temperature and high-humidity anti-warping pressure-sensitive adhesive also includes a curing agent, the amount of which is 0.2% to 1.0% of the total mass of the low-Tg acrylate copolymer component and the high-Tg acrylate copolymer component; The mass ratio of the low-Tg acrylate copolymer component to the high-Tg acrylate copolymer component is 10:(1~3).

6. A method for preparing a high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive according to any one of claims 1 to 5, characterized in that... Includes the following steps: Step 1: Prepare low-Tg acrylate copolymer components and high-Tg acrylate copolymer components separately; Step 2: Mix the low-Tg acrylate copolymer component and the high-Tg acrylate copolymer component evenly.

7. The preparation method according to claim 6, characterized in that... The preparation steps of the low Tg acrylate copolymer component include: adding C1-C of (meth)acrylate to a reaction vessel. 18 Alkyl ester monomer, first unsaturated monomer containing an acidic group, hydroxyl unsaturated monomer and solvent are introduced into the mixture at 23 ℃~50 ℃, nitrogen gas is introduced, the temperature is raised to 60 ℃~75 ℃, a free radical initiator is added, the reaction is carried out for 2 h~4 h, a second free radical initiator is added, and the reaction is carried out for another 2 h~8 h until the monomer conversion is complete. The preparation steps of the high Tg acrylate copolymer component include: mixing macromolecular protective colloid, water, and pH adjuster, stirring at a heating temperature until completely dissolved, with part of the dissolved macromolecular protective colloid located in the reaction vessel and the other part in the emulsification vessel; adding monomer mixture to the mixture in the emulsification vessel under stirring to obtain a pre-emulsion; adding a portion of the pre-emulsion to a crosslinking agent and mixing evenly; adding 7%~10% of the pre-emulsion to the reaction vessel, stirring evenly, and then adding a free radical initiator to obtain a seed emulsion; at 80 ℃~85 ℃, adding the pre-emulsion containing the crosslinking agent, the remaining pre-emulsion without the crosslinking agent, and the free radical initiator dropwise to the reaction vessel over 3~4 h; after the dropwise addition is complete, maintaining the temperature for 1h~2 h, lowering the temperature to 70 ℃, and then adding an oxidative-reduction initiator dropwise in parallel over 20 min~30 min, maintaining the temperature for 20 min~30 min; lowering the temperature to room temperature, adding a pH adjuster and preservative, and filtering; The preparation steps of the macromolecular protective colloid include: adding C1-C di(meth)acrylic acid to a reaction vessel containing a solvent. 18 Alkyl ester monomer, second unsaturated monomer containing acidic group and free radical initiator are introduced into nitrogen gas and reacted at 60 ℃~120 ℃ for 2 h~4 h. Then, a second free radical initiator is added and the reaction is continued for 2~4 h until the monomer conversion is complete. The vacuum device is turned on to remove the solvent and obtain macromolecular protective glue. The water is deionized water; the pH adjuster is at least one of ammonia, dimethylethanolamine, and triethanolamine; the free radical initiator is a thermal initiator, and is at least one of ammonium persulfate, sodium persulfate, and potassium persulfate; the redox initiator is at least one of ammonium persulfate-sodium bisulfite, ammonium persulfate-sodium metabisulfite, and tert-butyl hydroperoxide-sodium formaldehyde sulfoxylate; the preservative is at least one of chloromethylisothiazolinone (CMI), methylisothiazolinone (MI), benzisothiazolinone (BIT), 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), and 2-methyl-4-isothiazolin-3-one (MIT); Step two includes: drying, dehydrating and granulating the emulsion of the high Tg acrylate copolymer component, dispersing the high Tg acrylate copolymer component evenly in a solvent, mixing and stirring it evenly with the low Tg acrylate copolymer component, adjusting the viscosity, and adding a curing agent to mix evenly.

8. A high-temperature, high-humidity, anti-warping pressure-sensitive adhesive tape, characterized in that... It includes a substrate and a pressure-sensitive adhesive layer disposed on at least one side of the substrate, wherein the pressure-sensitive adhesive layer is made of a high-temperature and high-humidity anti-warping pressure-sensitive adhesive as described in any one of claims 1 to 5, or is made of a high-temperature and high-humidity anti-warping pressure-sensitive adhesive obtained by the preparation method described in claim 6 or 7.

9. The high-temperature and high-humidity resistant, anti-warping pressure-sensitive adhesive tape according to claim 8, characterized in that... The substrate is at least one of PET, PE, PP, BOPP, PVC, and paper; The substrate undergoes double-sided corona treatment, with the power controlled between 2.0 kW and 3.0 kW; The high-temperature and high-humidity anti-warping pressure-sensitive adhesive tape comprises a release film, a first adhesive layer, the substrate, a foamed adhesive layer, and a second adhesive layer stacked sequentially. The first adhesive layer and the second adhesive layer are made of the high-temperature and high-humidity anti-warping pressure-sensitive adhesive. The foamed adhesive layer is obtained by adding foaming microparticles to the high-temperature and high-humidity anti-warping pressure-sensitive adhesive and then foaming it. The total thickness of the first adhesive layer, the substrate, the foamed adhesive layer, and the second adhesive layer is 150μm to 450μm.

10. An adhesive composite material, characterized in that... The product includes a high-temperature and high-humidity anti-warping pressure-sensitive adhesive, PC, and aluminum. The high-temperature and high-humidity anti-warping pressure-sensitive adhesive bonds the PC and the aluminum. The high-temperature and high-humidity anti-warping pressure-sensitive adhesive is a high-temperature and high-humidity anti-warping pressure-sensitive adhesive according to any one of claims 1 to 5, or a high-temperature and high-humidity anti-warping pressure-sensitive adhesive obtained by the preparation method according to claim 6 or 7, or a high-temperature and high-humidity anti-warping pressure-sensitive tape according to claim 8 or 9.

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