An adhesive film for image display devices made of plastic

Abstract

Disclosed is an adhesive film for an image display device of a plastic material, which satisfies the following conditions: 1) a compliance at 50 DEG C, 8 kPa for 300 s is greater than 5 x 10 ‑5 Pa ‑1 ; 2) a phase angle at 120 DEG C, 0.1 Hz is greater than 5 DEG ; and 3) a storage modulus at 120 DEG C, 0.1 Hz is greater than 2 x 10 4 Pa. The adhesive film contains a high-Tg oligomer and an acrylic derivative polymer as raw materials. The adhesive film has both good adhesion and reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical display technology, and particularly relates to an adhesive film suitable for image display device of plastic material. BACKGROUND

[0002] OCA (Optically Clear Adhesive) is a special adhesive for bonding transparent optical elements (such as touch screens, displays, optical lenses, etc.). Traditional OCA optical adhesive tape has the advantages of colorless transparency, light transmittance of more than 90%, good bonding strength, small curing shrinkage, and no yellowing. OCA optical adhesive is generally used to connect the cover plate and the display module (LCD and OLED) in the display field. The cover plate usually has two materials: glass and plastic. Glass is widely used due to its good optical performance, wear resistance and excellent touch feeling. At the same time, plastic cover plates are mainly PC (polycarbonate), PMMA (polymethyl methacrylate) and MS (methyl methacrylate and styrene copolymer). Due to its low cost and explosion-proof performance, it plays an irreplaceable role in some occasions.

[0003] However, plastic cover plates are prone to release small molecule gases when subjected to high temperature reliability tests. Ordinary OCA is prone to bubble defects at this time. Therefore, the OCA for plastic cover plates generally uses a macromolecular high-crosslinking formula system to inhibit the reliability defects (such as CN108034364A). However, the filling rate and bonding ability of the macromolecular high-crosslinking OCA will be greatly affected, which is unacceptable to panel bonding factory customers.

[0004] Under this background, combined with the specific needs of the industry, it is urgent to develop an adhesive film for plastic cover plates that has good filling and reliability. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide an adhesive film for image display devices suitable for plastic materials.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: an adhesive film for image display devices suitable for plastic materials, the adhesive film satisfies the following conditions: 1) the compliance of 300s creep at 50℃, 8kPa is greater than 5x10 - 5 Pa -1 ; 2) the phase angle at 120℃, 0.1Hz is greater than 5°; 3) the storage modulus at 120℃, 0.1Hz is greater than 2x10 4 Pa, the raw material of the adhesive film contains high Tg oligomer and acrylic derivative polymer.

[0007] As a specific embodiment, the high Tg oligomer has a molecular weight of 10,000-30,000 and the high Tg oligomer is added in an amount of 3-7% of the acrylic derivative polymer.

[0008] As a specific embodiment, the raw material of the oligomer includes an acrylic monomer and a molecular weight regulator, the molecular weight regulator is added in an amount of 0.05-1.0% of the acrylic monomer.

[0009] As a specific embodiment, the acrylic monomer includes a hard monomer selected from one or more of isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butyl (meth)acrylate, methyl (meth)acrylate and a functional monomer selected from one or more of acryloyl morpholine, acrylamide, N-vinyl pyrrolidone.

[0010] As a specific embodiment, the molecular weight regulator is selected from a combination of one or more of n-dodecyl mercaptan, t-dodecyl mercaptan, isooctyl mercaptoacetate.

[0011] As a specific embodiment, the raw material of the oligomer further includes a cleavage type photoinitiator selected from a combination of one or more of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, benzoin dimethyl ether, which is added in an amount of 0.1-1% of the acrylic monomer.

[0012] As a specific embodiment, the synthetic monomer of the acrylic derivative polymer includes a C4-C18 acrylate monomer and a hydrophilic monomer.

[0013] As a specific embodiment, the C4-C18 acrylate monomer is selected from one or more of butyl (meth)acrylate, isooctyl (meth)acrylate, isobornyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate and isostearyl (meth)acrylate, which is added in an amount of 50-95% of the total mass of the raw material of the acrylic derivative polymer.

[0014] As a specific embodiment, the hydrophilic monomer is selected from one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, which is added in an amount of 5-30% of the total mass of the raw material of the acrylic derivative polymer.

[0015] As a specific embodiment, the acrylic derivative polymer further comprises a basic monomer selected from one or more of (meth) acrylamide, (meth) acrylmorpholine, N, N-dimethyl acrylamide, and the basic monomer is added in an amount of 0-20% of the total mass of the acrylic derivative polymer raw material.

[0016] As a specific embodiment, the raw material of the adhesive film further comprises a crosslinking agent selected from a combination of one or more of hexanediol diacrylate, tripropyleneglycol diacrylate, and trimethylolpropane triacrylate.

[0017] As a specific embodiment, the raw material of the adhesive film further comprises a photoinitiator, and the photoinitiator uses a cleavage type initiator selected from one or more of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, phenyl bis (2, 4, 6-trimethyl benzoyl) phosphine oxide, and benzoin dimethyl ether, and the addition amount is 0.05-0.5% of the addition amount of the acrylic derivative polymer.

[0018] Due to the use of the above technical solution, the present application has the following advantages compared with the prior art: the adhesive film for image display devices suitable for plastic materials of the present application uses acrylic derivative polymer and high Tg oligomer in the raw material, and the adhesive film has a compliance of greater than 5x10- 5 Pa- 1 at 50℃, 8kPa for 300s, a phase angle of greater than 5° at 120℃, 0.1Hz, and a storage modulus of greater than 2x10 4 Pa at 120℃, 0.1Hz, so that the adhesive sheet used on the plastic cover plate has good fitting and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of the structure of the fitting member during the fitting test; Figure 1 Figure 2 is a schematic diagram of the structure of the fitting member during the reliability test;

[0020] Figure 3 is a schematic diagram of the structure of the fitting member during the reliability test; Figure 2

[0021] Wherein: 1, adhesive film; 2, cover glass; 3, IOT film; 4, PC board. DETAILED DESCRIPTION

[0022] The technical solution of the present application will be further described below in conjunction with specific embodiments.

[0023] ​The present application provides an adhesive film for image display devices made of plastic material, the raw material of which comprises: an acrylic derivative polymer, a photoinitiator, a high Tg oligomer, and a crosslinking agent, the high Tg oligomer having a molecular weight of 10,000-30,000, and the addition amount of the high Tg oligomer being 3-7% of the addition amount of the acrylic derivative polymer.

[0024] I. Preparation of high Tg oligomer

[0025] Into a reaction vessel were added isobornyl methacrylate (IBOMA), acryloyl morpholine (ACMO), acrylamide (AM), benzoyl dimethyl ether (BDK), and n-dodecyl mercaptan (NDM), and nitrogen was replaced at a flow rate of 100 mL / min while stirring to mix them uniformly. Thereafter, polymerization was performed under a 365 nm LED lamp at 1.0 mW / cm 2 for 10 min to obtain an oligomer. The obtained oligomer was then subjected to a molecular weight test using gel permeation chromatography (GPC), and the addition amounts of the components and the test results are shown in Table 1.

[0026] Table 1

[0027]

[0028]

[0029] II. Preparation of adhesive film

[0030] Example 1

[0031] Into a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen injection tube were added isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g, and nitrogen was replaced at a flow rate of 100 mL / min while stirring to mix them uniformly. Thereafter, polymerization was performed under a 365 nm LED lamp at 1.0 mW / cm 2 to increase the solid content to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and prepolymer C 5.0 g were further added, and the mixture was stirred to dissolve uniformly and then degassed under vacuum at 0.95 MPa for 2 hours to obtain an adhesive resin composition for adhesive sheets.

[0032] After that, the adhesive sheet adhesive resin composition obtained in the above was dropped on a polyethylene terephthalate (PET) release film (release surface contact adhesive resin composition), and another PET release film was overlaid thereon (release surface contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated into a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ), to obtain a transparent adhesive sheet.

[0033] Example 2

[0034] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isobutyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen replacement was performed at a wind rate of 100 mL / min while stirring to mix uniformly. After that, polymerization was performed under a 1.0 mW / cm 2 of a 365 nm LED lamp, and the solid content was increased to 15%. After that, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and prepolymer B 5.0 g were further added, and after stirring to dissolve uniformly, defoaming was performed under a vacuum of 0.95 MPa for 2 hours, to obtain an adhesive sheet adhesive resin composition.

[0035] After that, the adhesive sheet adhesive resin composition obtained in the above was dropped on a polyethylene terephthalate (PET) release film (release surface contact adhesive resin composition), and another PET release film was overlaid thereon (release surface contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated into a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ), to obtain a transparent adhesive sheet.

[0036] Example 3

[0037] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isobutyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen replacement was performed at a wind rate of 100 mL / min while stirring to mix uniformly. After that, polymerization was performed under a 1.0 mW / cm 2The polymerization was performed under a 365 nm LED lamp to increase the solid content to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and prepolymer D 5.0 g were added, and after being uniformly dissolved by stirring, the mixture was degassed under a vacuum of 0.95 MPa for 2 hours to obtain an adhesive sheet adhesive resin composition.

[0038] Thereafter, the adhesive sheet adhesive resin composition obtained in the above was dropped on a polyethylene terephthalate (PET) release film (release surface contact adhesive resin composition), and another PET release film was overlaid thereon (release surface contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated into a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ) to obtain a transparent adhesive sheet.

[0039] Example 4

[0040] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and while being uniformly mixed by stirring, nitrogen gas was replaced at a wind speed of 100 mL / minute. Thereafter, the polymerization was performed under a 365 nm LED lamp to increase the solid content to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and prepolymer C 3.0 g were added, and after being uniformly dissolved by stirring, the mixture was degassed under a vacuum of 0.95 MPa for 2 hours to obtain an adhesive sheet adhesive resin composition. 2 In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and while being uniformly mixed by stirring, nitrogen gas was replaced at a wind speed of 100 mL / minute. Thereafter, the polymerization was performed under a 365 nm LED lamp to increase the solid content to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and prepolymer C 3.0 g were added, and after being uniformly dissolved by stirring, the mixture was degassed under a vacuum of 0.95 MPa for 2 hours to obtain an adhesive sheet adhesive resin composition.

[0041] Thereafter, the adhesive sheet adhesive resin composition obtained in the above was dropped on a polyethylene terephthalate (PET) release film (release surface contact adhesive resin composition), and another PET release film was overlaid thereon (release surface contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated into a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ) to obtain a transparent adhesive sheet.

[0042] Example 5

[0043] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen gas was replaced while stirring the mixture uniformly at a wind volume of 100 mL / min. Thereafter, polymerization was performed under a 1.0 mW / cm 2 of a 365 nm LED lamp, and the solid content was increased to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and prepolymer C 7.0 g were further added, and after stirring and dissolving uniformly, the mixture was degassed under a vacuum of 0.95 MPa for 2 hours to obtain an adhesive sheet adhesive resin composition.

[0044] Thereafter, the adhesive sheet adhesive resin composition obtained in the above (release face contact adhesive resin composition) was dropped on a polyethylene terephthalate (PET) release film, and another PET release film was overlaid thereon (release face contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated in a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet ray irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ), and a transparent adhesive sheet was obtained.

[0045] Comparative Example 1

[0046] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen gas was replaced while stirring the mixture uniformly at a wind volume of 100 mL / min. Thereafter, polymerization was performed under a 1.0 mW / cm 2 of a 365 nm LED lamp, and the solid content was increased to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.1 g and benzoyl dimethyl ether 1.0 g were further added, and after stirring and dissolving uniformly, the mixture was degassed under a vacuum of 0.95 MPa for 2 hours to obtain an adhesive sheet adhesive resin composition.

[0047] Thereafter, the adhesive sheet adhesive resin composition obtained in the above (release face contact adhesive resin composition) was dropped on a polyethylene terephthalate (PET) release film, and another PET release film was overlaid thereon (release face contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated in a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet ray irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm2 ), a transparent adhesive sheet was obtained.

[0048] Comparative Example 2

[0049] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen gas was replaced while stirring the mixture uniformly at a wind volume of 100 mL / min. Thereafter, polymerization was performed under a 365 nm LED lamp of 1.0 mW / cm 2 , and the solid content was increased to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.5 g and benzoyl dimethyl ether 1.0 g were further added, and after stirring and dissolving uniformly, defoaming was performed under a vacuum of 0.95 MPa for 2 hours, to obtain an adhesive resin composition for an adhesive sheet.

[0050] Thereafter, the adhesive resin composition for an adhesive sheet obtained in the above (adhesive resin composition for a release surface contact) was dropped on a polyethylene terephthalate (PET) release film, and another PET release film was overlaid thereon (adhesive resin composition for a release surface contact), and the adhesive resin composition for an adhesive sheet was coated in a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ), to obtain a transparent adhesive sheet.

[0051] Comparative Example 3

[0052] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen gas was replaced while stirring the mixture uniformly at a wind volume of 100 mL / min. Thereafter, polymerization was performed under a 365 nm LED lamp of 1.0 mW / cm 2 , and the solid content was increased to 15%. Thereafter, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and oligomer A 5.0 g were further added, and after stirring and dissolving uniformly, defoaming was performed under a vacuum of 0.95 MPa for 2 hours, to obtain an adhesive resin composition for an adhesive sheet.

[0053] After that, the adhesive sheet adhesive resin composition obtained in the above was dropped on a polyethylene terephthalate (PET) release film (release surface-contact adhesive resin composition), and another PET release film was overlaid thereon (release surface-contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated into a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ), to obtain a transparent adhesive sheet.

[0054] Comparative Example 4

[0055] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen replacement was performed while stirring and mixing uniformly at an air flow rate of 100 mL / min. After that, polymerization was performed under a 1.0 mW / cm 2 of a 365 nm LED lamp, and the solid content was increased to 15%. After that, hexanediol diacrylate (HDDA) 0.1 g, benzoyl dimethyl ether 1.0 g, and oligomer E 5.0 g were further added, and after stirring and dissolving uniformly, defoaming was performed under a vacuum of 0.95 MPa for 2 hours, to obtain an adhesive sheet adhesive resin composition.

[0056] After that, the adhesive sheet adhesive resin composition obtained in the above was dropped on a polyethylene terephthalate (PET) release film (release surface-contact adhesive resin composition), and another PET release film was overlaid thereon (release surface-contact adhesive resin composition), and the adhesive sheet adhesive resin composition was coated into a sheet shape using a roll, and ultraviolet rays were irradiated using an ultraviolet irradiation device (intensity: 1 mW / cm 2 , energy: 600 mJ / cm 2 ), to obtain a transparent adhesive sheet.

[0057] Comparative Example 5

[0058] In a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen gas injection tube, isooctyl acrylate 63.0 g, isobornyl acrylate 10.0 g, hydroxyethyl acrylate 10.0 g, isooctyl methacrylate 9.0 g, acryloyl morpholine 5.0 g, acrylamide 3.0 g, and benzoyl dimethyl ether 0.05 g were added, and nitrogen replacement was performed while stirring and mixing uniformly at an air flow rate of 100 mL / min. After that, polymerization was performed under a 1.0 mW / cm 2Polymerization was carried out under a 365nm LED lamp to increase the solid content to 15%. Then, 0.1g of hexanediol diacrylate (HDDA), 1.0g of benzoyl dimethyl ether and 1.0g of oligomer C were added, stirred and dissolved evenly, and then degassed under a vacuum of 0.95MPa for 2 hours to obtain an adhesive resin composition for adhesive sheets.

[0059] Next, the adhesive resin composition for adhesive sheets obtained above (release surface contact adhesive resin composition) is dropped onto a polyethylene terephthalate (PET) release film, and then another PET release film is placed on top of it (release surface contact adhesive resin composition). The adhesive resin composition for adhesive sheets is then coated into a sheet using a roller, and the sheet is irradiated with ultraviolet light (intensity 1 mW / cm²) using an ultraviolet irradiation device. 2 The energy is 600 mJ / cm 2 ), thus obtaining a transparent adhesive sheet.

[0060] Comparative Example 6

[0061] In a reaction vessel equipped with a thermometer, stirrer, and nitrogen injection pipe, 63.0 g of isooctyl acrylate, 10.0 g of isobornyl acrylate, 10.0 g of hydroxyethyl acrylate, 9.0 g of isooctyl methacrylate, 5.0 g of acrylmorpholine, 3.0 g of acrylamide, and 0.05 g of benzoyl dimethyl ether were added. The mixture was stirred until homogeneous while purging with nitrogen at a flow rate of 100 mL / min. Subsequently, the mixture was subjected to a nitrogen injection system at 1.0 mW / cm². 2 Polymerization was carried out under a 365nm LED lamp to increase the solid content to 15%. Then, 0.1g of hexanediol diacrylate (HDDA), 1.0g of benzoyl dimethyl ether and 0.0g of oligomer C1 were added, stirred and dissolved evenly, and then degassed under a vacuum of 0.95MPa for 2 hours to obtain an adhesive resin composition for adhesive sheets.

[0062] Next, the adhesive resin composition for adhesive sheets obtained above (release surface contact adhesive resin composition) is dropped onto a polyethylene terephthalate (PET) release film, and then another PET release film is placed on top of it (release surface contact adhesive resin composition). The adhesive resin composition for adhesive sheets is then coated into a sheet using a roller, and the sheet is irradiated with ultraviolet light (intensity 1 mW / cm²) using an ultraviolet irradiation device. 2 The energy is 600 mJ / cm 2 ), thus obtaining a transparent adhesive sheet.

[0063] Performance tests were conducted on the above embodiments and comparative examples, and the test results are shown in Table 2.

[0064] 1) 50℃ creep test

[0065] An adhesive sheet having a thickness of 1.0 mm and a diameter of 8 mm was prepared, and a dynamic viscoelasticity measuring device (Solids Analyzer RSA-II, manufactured by Pheometric Scientific) was used to measure the compliance value at 300 seconds under a stress of 8 kPa at 50°C under rotation.

[0066] ii) 120°C phase angle test

[0067] An adhesive sheet having a thickness of 1.0 mm and a diameter of 8 mm was prepared, and a dynamic viscoelasticity measuring device (Solids Analyzer RSA-II, manufactured by Pheometric Scientific) was used to measure the phase angle at different frequencies under a strain of 5% at 120°C under frequency sweep from 10 to 0.01 Hz.

[0068] iii) 120°C, 0.1 Hz storage modulus

[0069] An adhesive sheet having a thickness of 1.0 mm and a diameter of 8 mm was prepared, and a dynamic viscoelasticity measuring device (Solids Analyzer RSA-II, manufactured by Pheometric Scientific) was used to measure the storage modulus G' at 0.1 Hz under a strain of 5% at 120°C under frequency sweep from 10 to 0.01 Hz.

[0070] iv) Lamination test

[0071] The light film of the OCA was peeled off, and the OCA was attached to a 6.5-inch cover glass 2 having a 20-μm ink step difference using a roller, the heavy film of the OCA was peeled off, and the IOT film 3 was attached to the OCA 1 using a roller, and the resulting laminate was degassed at 45°C and 0.5 MPa for 15 minutes to obtain a laminate as shown in FIG. 1. Figure 1 The degassing of the laminate was observed, and the number and size of bubbles in the visual field were scored on a scale of 1 to 5.

[0072] 5 points: no bubbles;

[0073] 4 points: 5 or less small bubbles (0.5 mm or less in diameter);

[0074] 3 points: 5 to 10 small bubbles;

[0075] 2 points: 10 or more small bubbles or 1 to 5 large bubbles (0.5 mm or more in diameter);

[0076] 1 point: full screen of bubbles.

[0077] v) Reliability test

[0078] The light film of OCA was torn off, and the heavy film of OCA was torn off after the 6.5-inch PC plate 4 was attached to the OCA by a roller. Then, another 6.5-inch PC plate 4 was attached to the OCA 1, and the OCA was degassed at 45°C and 0.5 MPa for 15 min to obtain a laminated member as shown in Figure 2 After that, the laminated member was placed in an oven at 85°C for 3 hours, taken out, and scored 1 to 5 points according to the size and number of bubbles in the visual area.

[0079] 5 points: no bubbles;

[0080] 4 points: less than 5 small bubbles (diameter less than 0.5 mm);

[0081] 3 points: 5-10 small bubbles;

[0082] 2 points: more than 10 small bubbles or 1-5 large bubbles (diameter more than 0.5 mm);

[0083] 1 point: full screen of bubbles.

[0084] Table 2 - Properties of OCA glue and lamination and aging effects

[0085]

[0086]

[0087] In Table 2, from Examples 1, 4, 5 and Comparative Examples 5 and 6, we can see that when the amount of oligomer C is 3%-7% of the mass of the acrylic derivative polymer, the lamination and aging effects of the OCA glue are relatively good, and the optimal amount is between 5%-7%. From Examples 1, 2, 3 and Comparative Examples 3 and 4, we can see that when the weight average molecular weight of oligomers B, C and D is between 10,000-30,000, the lamination and aging effects of the OCA glue are relatively good, and the performance of oligomers B and C is the best. When oligomer A with a weight average molecular weight of 51,882 is added, the OCA haze is greater than 1, and when oligomer E with a weight average molecular weight of 6,771 is added, the aging effect is poor. In addition, from Comparative Examples 1 and 2, we can see that when no oligomer is added, the lamination and aging effects of the OCA glue cannot be achieved simultaneously.

[0088] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. An adhesive film suitable for image display devices made of plastic materials, characterized in that, The adhesive film meets the following conditions: 1) The creep compliance at 50℃ and 8kPa for 300s is greater than 5×10 -5 Pa -1 2) The phase angle at 120℃ and 0.1Hz is greater than 5°; 3) The energy storage modulus at 120℃ and 0.1Hz is greater than 2×10 4 Pa, the raw material of the adhesive film contains a high Tg oligomer and an acrylic derivative polymer. The high Tg oligomer has a molecular weight between 10,000 and 30,000, and the dosage of the high Tg oligomer is 3%-7% of the dosage of the acrylic derivative polymer. The raw material of the high Tg oligomer includes acrylic monomers and molecular weight regulators. The dosage of the molecular weight regulator is 0.05-1.0% of the dosage of the acrylic monomers. The synthetic monomers of the acrylic derivative polymer include C4-C18 acrylate monomers and hydrophilic monomers. The acrylic monomers include hard monomers and functional monomers. The hard monomers are selected from one or more of isobornyl methacrylate, cyclohexyl methacrylate, tert-butyl methacrylate, and methyl methacrylate. The functional monomers are selected from one or more of acrylamide, acrylamide, and N-vinylpyrrolidone.

2. The adhesive film for image display devices made of plastic materials according to claim 1, characterized in that, The molecular weight regulator is selected from one or more combinations of n-dodecyl mercaptan, tert-dodecyl mercaptan, and isooctyl mercaptoacetate.

3. The adhesive film for image display devices made of plastic materials according to claim 1, characterized in that, The C4-C18 acrylate monomer is selected from one or more of butyl methacrylate, isooctyl methacrylate, isobornyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, and isooctadecyl methacrylate, and the amount of the C4-C18 acrylate monomer added accounts for 50-95% of the total mass of the acrylic derivative polymer raw materials.

4. The adhesive film for image display devices made of plastic materials according to claim 1, characterized in that, The hydrophilic monomer is selected from one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate, and the amount of the hydrophilic monomer added accounts for 5-30% of the total mass of the acrylic derivative polymer raw material.

5. The adhesive film for image display devices made of plastic materials according to claim 1, characterized in that, The acrylic derivative polymer further comprises a basic monomer selected from one or more of (meth)acrylamide, (meth)acryloylmorpholine, and N,N-dimethylacrylamide, and the amount of the basic monomer added accounts for 0-20% of the total mass of the acrylic derivative polymer raw material.

6. The adhesive film for image display devices made of plastic materials according to claim 1, characterized in that, The adhesive film raw material also contains a crosslinking agent, which is selected from one or more combinations of glycol diacrylate, tripropylene glycol diacrylate, and trimethylolpropane triacrylate.

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