Organic silicon optical adhesive composition, organic silicon optical adhesive film containing organic silicon optical adhesive composition and application of organic silicon optical adhesive film

Abstract

The invention provides an organic silicon optical cement composition, an organic silicon optical cement film containing the same and application of the organic silicon optical cement film. The organic silicon optical cement composition comprises a component A and a component B, the component A comprises the following components in parts by weight: 10-25 parts of vinyl silicone oil, 10-20 parts of vinyl silicone resin, 0.1-2 parts of a first catalyst and 7-18 parts of alkoxy silicone oil; and the component B comprises the following components in parts by weight: 2-10 parts of hydrogen-containing silicon resin, 15-30 parts of vinyl silicone oil, 20-30 parts of methyl MQ silicon resin and 0.1-0.5 part of a second catalyst. The organic silicon optical adhesive composition has high bonding performance, low storage modulus under a low temperature condition and excellent high and low temperature bending resistance, so that a foldable screen has higher bending reliability at outdoor high temperature and low temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic silicon materials, and specifically relates to an organic silicon optical adhesive composition, an organic silicon optical adhesive film containing the same, and applications thereof. Background Art

[0002] Organic light-emitting diodes (OLEDs) are self-luminous; since they don't require an external light source, OLED screens can be made thinner. Compared to LCD screens, they also offer wider viewing angles, higher contrast, faster response times, and more vibrant colors. Due to their flexibility, OLED screens are increasingly being used in smartphones, creating a variety of innovative phone designs.

[0003] Optically clear adhesive film (OCA film) is an important component of smartphone OLED touch display screens. Compared with traditional LCD screens, the OCA film used in flexible OLED screens has new properties. In addition to basic properties such as high light transmittance, low haze, a refractive index close to that of the substrate and good adhesion, it also needs to have high flow filling properties, dynamic and static bending properties, and optical improvement performance. Currently, all optically clear adhesive films (OCA) for folding on the market are acrylic system materials. Under low temperature conditions (-30°C), the storage modulus of the optical film is 4 times or more than that at room temperature (the storage modulus at room temperature is about 50Kpa, and greater than 200Kpa at low temperature). In severe cases, the screen cannot even be opened or closed. Moreover, when used in low and high temperature environments, the adhesion of OCA drops sharply, greatly affecting the opening and closing reliability of the folding screen.

[0004] To reduce the storage modulus of optical films at low temperatures (e.g., -20°C to 0°C) and improve stress distribution when the screen is bent, silicone-based optical adhesives are used instead of acrylic-based materials. Silicone materials have a polysiloxane backbone. Due to their unique structure, silicone combines the properties of both inorganic and organic materials. Compared to acrylic folding OCAs, silicone materials have wider bond angles (Si-O-Si angle of 140°, CC angle of 120°), resulting in greater free volume, less rotational resistance, and lower internal stress. Furthermore, silicone bond lengths of 1.7 angstroms, compared to acrylic's 1.5 angstroms, enhance moisture and oxygen permeability. Silicone also possesses high elasticity, facilitating stress release. Furthermore, silicone bond energy of 444 kJ / mol, also greater than acrylic's 356 kJ / mol, offers excellent weather resistance. Its low and stable modulus also allows for a wider range of applications. However, silicone-based optical adhesives still have significant drawbacks. First, some technical solutions achieve low-temperature modulus control by adding polysiloxane (raw rubber) that does not contain active reactive groups. However, due to the lack of active reactive groups in the raw rubber molecular chain, uncrosslinked free raw rubber is easily precipitated from the system, resulting in attenuation of the adhesive force at the interface of the adhesive layer and insufficient bonding stability. While reducing the storage modulus, the bonding strength is generally sacrificed, affecting the long-term reliability of the screen module. Secondly, in order to maintain the bonding strength of the adhesive under high and low temperature cycles, the existing technology usually requires the introduction of a large amount of MQ resin to increase the cohesive energy, but the three-dimensional cross-linked structure of the MQ resin will significantly increase the modulus of the adhesive layer, especially under low temperature conditions. The modulus increase is more obvious, making it difficult to take into account both high bonding strength and low-temperature flexibility requirements. Third, some solutions improve low-temperature adhesion by adding a high proportion of silane coupling agent, but excessive alkoxy groups easily absorb environmental moisture to produce by-products, causing the adhesive layer to fog, reducing optical transmittance, and affecting the screen display effect; in addition, there are solutions that use polysiloxane co-modified with alkoxy and vinyl. Although it can improve adhesion, the increase in cross-linking points and the enhanced rigidity of the molecular chain segments lead to the obstruction of molecular chain movement at low temperatures, and the low-temperature storage modulus is high, which easily causes microcracks to expand.

[0005] Therefore, there is an urgent need to develop a silicone optical adhesive composition that can maintain a low storage modulus at low temperatures and has both high bonding stability and optical transparency to meet the dual requirements of durability and display performance for foldable screen mobile phones. Summary of the Invention

[0006] To address the shortcomings of the prior art, the present invention provides a silicone optical adhesive composition, a silicone optical adhesive film containing the same, and applications thereof. The silicone optical adhesive composition combines high bonding performance, a low storage modulus at low temperatures, and excellent high- and low-temperature bending resistance, enabling foldable screens to exhibit enhanced bending reliability in both high and low-temperature outdoor conditions.

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

[0008] In a first aspect, the present invention provides an organic silicone optical adhesive composition, which includes a component A and a component B; in parts by weight, the component A includes 10 to 25 parts of vinyl silicone oil, 10 to 20 parts of vinyl silicone resin, 0.1 to 2 parts of a first catalyst and 7 to 18 parts of alkoxy silicone oil; in parts by weight, the component B includes 2 to 10 parts of hydrogenated silicone resin, 15 to 30 parts of vinyl silicone oil, 20 to 30 parts of methyl MQ silicone resin and 0.1 to 0.5 parts of a second catalyst.

[0009] In the present invention, the alkoxy silicone oil contains flexible long siloxane chain segments, which can enable the composition to maintain a low storage modulus at a relatively low temperature. At the same time, the condensation or hydrogen bond formation between the active alkoxy groups is beneficial to improving the bonding performance of the composition. Furthermore, by combining it with a specific content of MQ silicone resin, a resin composition can be obtained that has good bonding performance, higher bending reliability at both high and low temperatures, and a lower storage modulus at low temperatures, thereby improving the opening and closing reliability of the folding screen under high and low temperature conditions.

[0010] In the present invention, 10 to 25 parts of vinyl silicone oil can be, for example, 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, 15.5 parts, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 18.5 parts, 19 parts, 19.5 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, etc.

[0011] In the present invention, 10 to 20 parts of vinyl silicone resin can be, for example, 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, 15.5 parts, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 18.5 parts, 19 parts, 19.5 parts, 20 parts, etc.

[0012] In the present invention, 0.1 to 2 parts of the first catalyst can be, for example, 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, etc.

[0013] In the present invention, 7 to 18 parts of alkoxy silicone oil can be, for example, 7 parts, 7.2 parts, 7.5 parts, 7.8 parts, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts, 10 parts, 10.2 parts, 10.5 parts, 10.8 parts, 11 parts, 11.2 parts, 11.5 parts, 11.8 parts, 12 parts, 12.2 parts , 12.5 parts, 12.8 parts, 13 parts, 13.2 parts, 13.5 parts, 13.8 parts, 14 parts, 14.2 parts, 14.5 parts, 14.8 parts, 15 parts, 15.2 parts, 15.5 parts, 15.8 parts, 16 parts, 16.2 parts, 16.5 parts, 16.8 parts, 17 parts, 17.2 parts, 17.5 parts, 17.8 parts, 18 parts, etc.

[0014] In the present invention, 2 to 10 parts of the hydrogen-containing silicone resin can be, for example, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0015] In the present invention, 15 to 30 parts of vinyl silicone oil can be, for example, 15 parts, 16 parts, 18 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, etc.

[0016] In the present invention, 20 to 30 parts of methyl MQ silicone resin can be, for example, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, etc.

[0017] In the present invention, 0.1 to 0.5 parts of the second catalyst can be, for example, 0.1 part, 0.12 part, 0.15 part, 0.18 part, 0.2 part, 0.22 part, 0.25 part, 0.28 part, 0.3 part, 0.32 part, 0.35 part, 0.38 part, 0.4 part, 0.42 part, 0.45 part, 0.48 part, 0.5 part, etc.

[0018] Preferably, the vinyl silicone oil in the component A and the component B is independently selected from the compound having the structure shown in Formula I.

[0019]

[0020] In Formula I, a is selected from an integer ≥ 1, for example, 1, 2, 4, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, 35, 40, 45, 50, etc.

[0021] Preferably, the vinyl content in the vinyl silicone resin in component A is 0.1 to 0.4 mmol / g, for example, it can be 0.1 mmol / g, 0.12 mmol / g, 0.14 mmol / g, 0.16 mmol / g, 0.18 mmol / g, 0.2 mmol / g, 0.22 mmol / g, 0.24 mmol / g, 0.26 mmol / g, 0.28 mmol / g, 0.3 mmol / g, 0.32 mmol / g, 0.34 mmol / g, 0.36 mmol / g, 0.38 mmol / g, 0.4 mmol / g, etc.

[0022] Preferably, the number average molecular weight of the vinyl silicone resin is 3500-6500, for example, 3500, 3500, 3800, 4000, 4200, 4400, 4600, 4800, 5000, 5200, 5400, 5600, 5800, 6000, 6200, 6400, 6500, etc.

[0023] Preferably, the vinyl silicone resin in component A includes any one of MQ vinyl silicone resin, MT vinyl silicone resin, MDT vinyl silicone resin or MTQ vinyl silicone resin, or a combination of at least two thereof, and more preferably MQ vinyl silicone resin.

[0024] Preferably, the ratio of M to Q in the MQ vinyl silicone resin is 0.7 to 0.9, for example, it can be 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, etc.

[0025] Preferably, the first catalyst in the A component comprises a platinum catalyst.

[0026] Preferably, the platinum catalyst includes any one of chloroplatinic acid, Karstedt platinum catalyst or Willing platinum catalyst, or a combination of at least two thereof.

[0027] Preferably, the alkoxy silicone oil in component A has a structure shown in Formula II.

[0028]

[0029] In Formula II, R1 is the same or different and is independently selected from a substituted or unsubstituted C1-C12 linear or branched alkyl group; R2 is the same or different and is independently selected from H, a substituted or unsubstituted C1-C12 linear or branched alkyl group; R3 is the same or different and is independently selected from a C1-C6 linear or branched alkoxy group; n1 and n2 are independently selected from integers ≥ 0, such as 0, 1, 2, 3, 4, 5, 6, etc.; b is selected from an integer of 180 to 280, such as 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, etc. The substituted substituents include halogen.

[0030] In the present invention, the C1-C12 straight chain or branched chain alkyl group may be, for example, a C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, or C12 straight chain or branched chain alkyl group, illustratively including a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a n-pentyl group, a n-hexyl group, and the like.

[0031] In the present invention, the C1 to C6 straight chain or branched alkoxy group may be, for example, a C1, C2, C3, C4, C5, or C6 straight chain or branched alkoxy group; illustratively including methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, n-pentoxy, n-hexoxy, and the like.

[0032] Preferably, the viscosity of component A is 80,000 to 200,000 mPa·s, for example, 80,000 mPa·s, 100,000 mPa·s, 120,000 mPa·s, 140,000 mPa·s, 160,000 mPa·s, 180,000 mPa·s, 200,000 mPa·s, etc.; more preferably, 100,000 to 150,000 mPa·s.

[0033] Preferably, the hydrogenated silicone resin in component B has the structural formula (H c R 2 3-c SiO 0.5 ) x (SiO2) y ; Among them, R 2 Any one selected from C1-C10 straight chain or branched alkyl (for example, C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 straight chain or branched alkyl), C6-C15 aryl (for example, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15 aryl); c is an integer selected from 1 to 3, for example, 1, 2, 3; x and y are each independently selected from an integer >0.

[0034] Preferably, the ratio of x to y in the hydrogenated silicone resin is 0.6 to 1, for example, 0.6, 0.7, 0.8, 0.9, 1, etc.

[0035] Preferably, the hydrogen content in the hydrogen-containing silicone resin is 1 to 10 mmol / g, for example, 1 mmol / g, 2 mmol / g, 3 mmol / g, 4 mmol / g, 5 mmol / g, 6 mmol / g, 7 mmol / g, 8 mmol / g, 9 mmol / g, 10 mmol / g, etc.

[0036] Preferably, the weight average molecular weight of the hydrogenated silicone resin is 1000 to 10000, for example, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, etc.

[0037] Preferably, the number average molecular weight of the methyl MQ silicone resin in the B component is 3000-10000 g / mol, for example, 3000 g / mol, 4000 g / mol, 5000 g / mol, 6000 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, etc.

[0038] Preferably, the ratio of M to Q in the methyl MQ silicone resin is 0.6 to 1, for example, 0.6, 0.7, 0.8, 0.9, 1, etc.

[0039] Preferably, the second catalyst in the B component comprises an organic titanium catalyst.

[0040] Preferably, the organic titanium catalyst comprises any one or a combination of at least two of diisopropoxyethyl acetoacetate titanium, diisopropyl bis titanate, titanium isooctoxide or titanate chelate.

[0041] In the present invention, the first catalyst is selected from a platinum catalyst, which is used to catalyze the addition of silicon and hydrogen; the second catalyst is selected from an organic titanium catalyst, which is used to catalyze the dealcoholization condensation of alkoxy silicone oil. Through compounding of the two curing mechanisms, the silica gel prepared from vinyl silicone resin and hydrogen-containing silicone resin is used as the main body, and a certain proportion of terminal alkoxy silicone oil is compounded. The optically transparent adhesive film obtained has the characteristics of stable high and low temperature modulus and high adhesion.

[0042] Preferably, the component B further comprises 0.5 to 2 parts of an inhibitor in parts by weight, for example, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, etc.

[0043] Preferably, the inhibitor comprises at least one of an alkynol compound, a vinyl ring compound, a polyvinyl silicone oil or a maleate compound.

[0044] Preferably, the viscosity of component B is 100,000 to 150,000 mPa·s, for example, 100,000 mPa·s, 110,000 mPa·s, 120,000 mPa·s, 130,000 mPa·s, 140,000 mPa·s, 150,000 mPa·s, etc.; more preferably, it is 100,000 to 120,000 mPa·s.

[0045] Preferably, the mass ratio of component A to component B is 1:(0.5-1.5), wherein the specific value of (0.5-1.5) can be, for example, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, etc.

[0046] In the present invention, as a preferred technical solution, the component A includes, by weight, 12.5 to 22.5 parts of vinyl silicone oil, 12.5 to 22.5 parts of vinyl silicone resin, 0.5 to 1.5 parts of a first catalyst and 11 to 15 parts of alkoxy silicone oil; the component B includes, by weight, 2 to 5 parts of hydrogenated silicone resin, 15 to 25 parts of vinyl silicone oil, 22 to 30 parts of methyl MQ silicone resin, 0.1 to 0.5 parts of a second catalyst and 0.5 to 2 parts of an inhibitor.

[0047] In the present invention, the preparation method of the organic silicone optical adhesive composition includes: mixing vinyl silicone oil, vinyl silicone resin, a first catalyst and alkoxy silicone oil at 100 to 500 rpm, filtering to obtain component A; mixing hydrogenated silicone resin, vinyl silicone oil, methyl MQ silicone resin, a second catalyst and an optional inhibitor at 100 to 500 rpm, filtering to obtain component B; and mixing components A and B to obtain the organic silicone optical adhesive composition.

[0048] In a second aspect, the present invention provides a high-low temperature resistant bending silicone optical adhesive film, wherein the silicone optical adhesive film comprises the silicone optical adhesive composition described in the first aspect.

[0049] In the present invention, the high and low temperature resistant bending silicone optical adhesive film comprises a first release film, an optical adhesive layer and a second release film stacked in sequence; the material of the optical adhesive layer comprises the silicone optical adhesive composition described in the first aspect.

[0050] In the present invention, the thickness of the optical adhesive layer is 10-50 μm, for example, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.

[0051] In the present invention, the preparation method of the high and low temperature resistant bending silicone optical adhesive film comprises the following steps: coating the silicone optical adhesive composition on the surface of a first release film, laminating a second release film, and curing to obtain the silicone optical adhesive film.

[0052] In the present invention, the first release film is a light release film; the second release film is a heavy release film; the coating method includes roller coating; the curing includes pre-curing at 80-90°C for 10-50 minutes and then aging at 50-70°C for 36-72 hours.

[0053] In the present invention, the organic silicone optical adhesive film can be cut into any size according to actual needs.

[0054] In a third aspect, the present invention provides a foldable display screen, wherein the material of the foldable display screen includes the organic silicone optical adhesive composition described in the first aspect or the organic silicone optical adhesive film described in the second aspect.

[0055] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The silicone optical adhesive composition provided by the present invention comprises component A which is compounded with other components using a specific content of alkoxy silicone oil, and component A is compounded with component B at the same time. The optically transparent adhesive film formed has a lower modulus at room temperature and low temperatures, is used for bonding folding screens, has higher peel strength, and has good high and low temperature bending resistance, which significantly improves the high and low temperature opening and closing reliability of the folding screen, especially the opening and closing reliability under low temperature conditions. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0059] The materials used in the examples and comparative examples of the present invention can be purchased commercially or prepared by conventional methods. Unless otherwise specified, the materials used in the present invention are as follows:

[0060] Vinyl silicone oil: V-15W purchased from Jiangsu Keqi Polymer Materials Research Institute Co., Ltd., with a viscosity of 150,000 mPa·s and a vinyl content of 0.015 mmol / g.

[0061] Vinyl silicone resin: YF100515 purchased from Delta Silicones, with a molecular weight of 4500 and a vinyl content of 0.22 mmol / g.

[0062] Platinum catalyst: BC-PT20 purchased from Dongguan Bochang New Material Technology Co., Ltd., with a viscosity of 1000 mPa·s and a platinum content of 2000 ppm.

[0063] Alkoxy silicone oil

[0064] Alkoxy silicone oil 1: The structural formula is b=268; the preparation method of the alkoxy silicone oil 1 comprises: adding 200g of vinyl silicone oil (molecular weight of 20,000, vinyl mass percentage of 0.297%) to a four-necked flask, performing reduced pressure distillation, heating to 120°C for 30 minutes; using nitrogen to release the pressure, and cooling to 50°C under a nitrogen atmosphere; after turning off the nitrogen, adding 3.506g of trimethoxysilane, stirring for 5 minutes, adding 10ppm of platinum catalyst using a constant pressure dropping funnel, and maintaining the reaction at 60°C for 5 hours; after the reaction is completed, heating to 100°C, evacuating the mixture for 3 hours, discharging the mixture, and sealing and storing it to obtain the alkoxy silicone oil 1.

[0065] Alkoxy silicone oil 2: The difference between it and alkoxy silicone oil 1 is that b=220, and the structure is the same as alkoxy silicone oil 1; in the preparation method, it can be replaced with vinyl silicone oil of corresponding molecular weight.

[0066] Alkoxy silicone oil 3: The difference between it and alkoxy silicone oil 1 is that b=170, and the structure is the same as alkoxy silicone oil 1; in the preparation method, it can be replaced with vinyl silicone oil of corresponding molecular weight.

[0067] Alkoxy silicone oil 4: The difference between it and alkoxy silicone oil 1 is that b=290, and the structure is the same as alkoxy silicone oil 1; in the preparation method, it can be replaced with vinyl silicone oil of corresponding molecular weight.

[0068] Alkoxy silicone oil 5: The structural formula is m=220, n=48; the preparation method comprises: mixing a dihydroxyl-terminated vinyl silicone oil with an acid-binding agent, triethylamine (15% by mass of trimethoxychlorosilane), and trimethoxychlorosilane, wherein the molar ratio of the hydroxyl group in the dihydroxyl-terminated vinyl silicone oil to the trimethoxychlorosilane is 1:1.1; then reacting at 40° C. for 4 h, heating to 120° C., performing reduced pressure distillation for 1 h, and cooling to room temperature to obtain the alkoxy silicone oil 5.

[0069] Hydrogen-containing silicone resin: DY-YF2303-27 purchased from Shandong Dayi Chemical, with a viscosity of 165 mPa·s and an active hydrogen content of 6.8 mmol / g.

[0070] Methyl MQ silicone resin: XJY-8205-05 purchased from Jiangxi Xinjiayi New Materials Co., Ltd., with a molecular weight of 5000 and a ratio of M to Q of 0.8.

[0071] Organic titanium catalyst: titanium isooctoxide purchased from Sane Chemical Technology (Shanghai) Co., Ltd., with an organic titanium content of 100 ppm.

[0072] Inhibitor: B103673 purchased from Delta Silicones.

[0073] Examples 1 to 7, Comparative Examples 1 to 4

[0074] Examples 1 to 7 and Comparative Examples 1 to 4 respectively provide a silicone optical adhesive composition, including component A and component B, and the mass ratio of component A to component B is 1:1; the formulas of component A and component B in parts by weight are shown in Tables 1 to 2; wherein, “ / ” indicates that the component is not included in the formula.

[0075] The preparation method of the organic silicone optical adhesive composition includes: mixing vinyl silicone oil, vinyl silicone resin, a first catalyst and alkoxy silicone oil at 300 rpm, filtering to obtain component A; mixing hydrogenated silicone resin, vinyl silicone oil, methyl MQ silicone resin, a second catalyst and an optional inhibitor at 300 rpm, filtering to obtain component B; and mixing components A and B to obtain the organic silicone optical adhesive composition.

[0076] Table 1

[0077]

[0078] Table 2

[0079]

[0080]

[0081] Application Examples

[0082] A silicone optical adhesive film that is resistant to high and low temperature bending, the silicone optical adhesive film that is resistant to high and low temperature bending comprising a light release film, an optical adhesive layer (with a thickness of 35 μm) and a heavy release film stacked in sequence; the material of the optical adhesive layer comprises the silicone optical adhesive composition provided in Examples 1 to 7 and Comparative Examples 1 to 4.

[0083] The preparation method of the high-temperature and low-temperature resistant silicone optical adhesive film includes the following steps: roll-coating the silicone optical adhesive composition on the surface of a light release film, laminating a heavy release film, pre-curing at 85°C for 30 minutes, winding the material, and then aging the coiled material at 60°C for 48 hours to obtain the silicone optical adhesive film.

[0084] Performance Testing

[0085] (1) Bending resistance test: The organic silicone optical adhesive film is used to bond the PET substrate and the polarizer for the folding screen; the specific steps include: (1) using plasma to treat the folding PET substrate and the polarizer for the folding screen, peeling off the light release film of the organic silicone optical transparent adhesive film, and laminating the organic silicone optical transparent adhesive film on the PET substrate by a roller, and then peeling off the heavy release film, and laminating the polarizer of the folding screen by a roller again; (2) performing high-pressure degassing on the materials laminated in step (1), and the degassing parameters are 5kg / 60℃ / 30min; (3) after the degassing material is left to stand at room temperature for 24h, the bending resistance test is performed at different temperatures.

[0086] (2) Peel strength: Tested according to GB / T2791-1995 Adhesive T peel strength test method.

[0087] (3) Creep rebound: GB / T 11546.1-2008 Determination of creep properties of plastics Part 1: Tensile creep Vulcanized rubber and rubber products: Compression creep, shear creep, tensile stress relaxation, compression force GB / T19242 Vulcanized rubber - Determination of creep under compression or shear, GB / T 9871 Vulcanized rubber or thermoplastic rubber - Determination of aging properties.

[0088] (4) Stress relaxation: tensile stress relaxation test according to GB / T 9871 Vulcanized rubber or thermoplastic rubber - Determination of aging properties;

[0089] (5) Storage modulus: Tested in accordance with the Young's modulus, shear modulus and Poisson's ratio test methods of GB / T 7962.23-1987 colorless optical glass test methods.

[0090] (6) Tg point test: GB / T33061.1-2016 Determination of dynamic mechanical properties.

[0091] The specific test results are shown in Tables 3 and 4.

[0092] Table 3

[0093]

[0094] Table 4

[0095]

[0096]

[0097] As can be seen from Tables 3 and 4, the silicone optical adhesive composition provided by the present invention comprises component A, which is compounded with other components using a specific amount of alkoxy silicone oil. Component A is compounded with component B, and the resulting optically transparent adhesive film has a lower modulus at low temperatures. This film is used for bonding foldable screens and has higher peel strength and good high and low temperature bending resistance, significantly improving the high and low temperature opening and closing reliability of foldable screens, especially the opening and closing reliability under low temperature conditions. The material comprising the silicone optical adhesive composition has a low-temperature modulus of ≤175.6 kPa at -20°C, a peel strength of ≥363 gf / 25 mm, creep rebound of ≥72.7%, stress relaxation of ≥71.2%, and a high resistance to bending at both high and low temperatures. The low-temperature modulus can even reach ≤93.9 kPa at -20°C, a peel strength of ≥515 gf / 25 mm, creep rebound of ≥80%, stress relaxation of ≥75%, and a resistance to bending at -20°C and 60°C of more than 80,000 times.

[0098] It can be seen from Comparative Example 1 that the B component does not contain a catalyst, and the compounding of the two curing methods cannot be achieved, resulting in poor bonding performance and bending resistance of the silicone optical adhesive.

[0099] It can be seen from Comparative Examples 2 and 3 that the content of alkoxy silicone oil in component A is not within a specific range, and the silicone optical adhesive cannot take into account good bonding performance, bending resistance and low modulus under low temperature conditions.

[0100] It can be seen from Comparative Example 4 that there is no alkoxy silicone oil in the A component, the modulus of the silicone optical adhesive at low temperature conditions is significantly increased, and the bonding performance and bending resistance are deteriorated.

[0101] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A silicone optical adhesive composition, characterized in that: The organic silicon optical adhesive composition comprises component A and component B; In parts by weight, the component A comprises 10 to 25 parts of vinyl silicone oil, 10 to 20 parts of vinyl silicone resin, 0.1 to 2 parts of a first catalyst and 7 to 18 parts of alkoxy silicone oil; In parts by weight, the component B includes 2 to 10 parts of hydrogenated silicone resin, 15 to 30 parts of vinyl silicone oil, 20 to 30 parts of methyl MQ silicone resin and 0.1 to 0.5 parts of a second catalyst.

2. The organic silicone optical adhesive composition according to claim 1, characterized in that: The vinyl silicone oils in component A and component B are each independently selected from compounds having a structure shown in formula I; In formula I, a is selected from an integer ≥1.

3. The organic silicone optical adhesive composition according to claim 1 or 2, characterized in that: The vinyl content of the vinyl silicone resin in component A is 0.1 to 0.4 mmol / g; Preferably, the number average molecular weight of the vinyl silicone resin is 3500 to 6500; Preferably, the vinyl silicone resin includes any one of MQ vinyl silicone resin, MT vinyl silicone resin, MDT vinyl silicone resin or MTQ vinyl silicone resin, or a combination of at least two thereof, and more preferably MQ vinyl silicone resin.

4. The organic silicone optical adhesive composition according to any one of claims 1 to 3, characterized in that: The first catalyst in the A component includes a platinum catalyst; Preferably, the platinum catalyst comprises any one or a combination of at least two of chloroplatinic acid, Karstedt platinum catalyst or Willing platinum catalyst; Preferably, the alkoxy silicone oil in component A has a structure shown in Formula II; In Formula II, R1 is the same or different and is independently selected from substituted or unsubstituted C1-C12 linear or branched alkyl; R2 is the same or different and is independently selected from any one of H, substituted or unsubstituted C1-C12 linear or branched alkyl; R3 is the same or different and is independently selected from C1-C6 linear or branched alkoxy; the substituted substituent includes halogen; n1 and n2 are each independently selected from an integer ≥ 0; b is selected from an integer from 180 to 280; Preferably, the viscosity of component A is 80,000 to 200,000 mPa·s, more preferably 100,000 to 150,000 mPa·s.

5. The organic silicone optical adhesive composition according to any one of claims 1 to 4, characterized in that: The structural formula of the hydrogenated silicone resin in component B is (H c R 2 3-c SiO 0.5 ) x (SiO2) y ; Among them, R 2 Any one selected from C1-C10 straight-chain or branched alkyl groups, C6-C15 aryl groups; c is selected from an integer of 1-3; x and y are each independently selected from an integer greater than 0; Preferably, the ratio of x to y in the hydrogenated silicone resin is 0.6 to 1; Preferably, the hydrogen content in the hydrogen-containing silicone resin is 1 to 10 mmol / g.

6. The organic silicone optical adhesive composition according to any one of claims 1 to 5, characterized in that: The number average molecular weight of the methyl MQ silicone resin in the B component is 3000 to 10000 g / mol; Preferably, the ratio of M to Q in the methyl MQ silicone resin is 0.6 to 1; Preferably, the second catalyst in the B component comprises an organic titanium catalyst; Preferably, the organic titanium catalyst comprises any one or a combination of at least two of diisopropoxyethyl acetoacetate titanium, diisopropyl bis titanate, titanium isooctoxide or titanate chelate.

7. The organic silicone optical adhesive composition according to any one of claims 1 to 6, characterized in that: In parts by weight, the component B further comprises 0.5 to 2 parts of an inhibitor; Preferably, the inhibitor comprises at least one of an alkynol compound, a vinyl ring compound, a polyvinyl silicone oil or a maleate compound.

8. The organic silicone optical adhesive composition according to any one of claims 1 to 7, characterized in that: The viscosity of the B component is 100,000 to 150,000 mPa·s, more preferably 100,000 to 120,000 mPa·s; Preferably, the mass ratio of component A to component B is 1:(0.5-1.5).

9. A high and low temperature resistant silicone optical adhesive film, characterized in that: The organic silicone optical adhesive film comprises the organic silicone optical adhesive composition according to any one of claims 1 to 8.

10. A foldable display screen, characterized in that: The material of the foldable display screen includes the organic silicone optical adhesive composition according to any one of claims 1 to 8 or the organic silicone optical adhesive film according to claim 9.

Images