Adhesive Composition, Preparation Method Thereof, Optical Adhesive Film and Application Thereof

Abstract

The present application provides an adhesive composition, which includes an adhesive matrix and a modified polymer. Among them, the main chain of the modified polymer contains boron-oxygen coordination and / or boron-boron-oxygen coordination bonds, and the end group and / or side chain of the modified polymer contains at least one of a hydroxyl group, an acrylate group, and a vinyl group. The present application also provides a preparation method of the resin composition, an optical adhesive film, a folding screen using the optical adhesive film, and an electronic device using the optical adhesive film or the folding screen. The present application introduces boron-oxygen coordination bonds and / or boron-boron-oxygen coordination bonds into the molecular main chain of the modified polymer, so that the adhesive composition has excellent energy absorption and impact resistance performance on the premise of ensuring the bonding strength, thereby improving the impact resistance performance of the folding screen and reducing failure phenomena such as black spots or broken bright spots on the panel caused by external force impact.

Description

Technical Field

[0001] The present application relates to an adhesive composition, a preparation method of the adhesive composition, an optical adhesive film prepared from the adhesive composition, a folding screen containing the optical adhesive film, and an electronic device containing the optical adhesive film or the folding screen. Background Art

[0002] Due to the foldable screen of the foldable screen electronic device, it brings a brand-new visual experience and convenience to users in the fields of reading, gaming, office work, etc., and is increasingly favored by people.

[0003] Currently, the structure of the folding screen mainly includes a panel and a cover plate located on the front of the panel. The base material of the cover plate is an organic film material with excellent bendability, such as polyimide film (PI), polyethylene terephthalate film (PET), etc. Among them, adjacent two layers of base materials in the cover plate and between the cover plate and the panel are bonded together by an optical clear adhesive (OCA) or a liquid optical clear adhesive (LOCA).

[0004] However, most of the existing OCA / LOCA systems are acrylate polymer systems or silicone polymer systems, with an excessively low elastic modulus, about 10 Kpa - 500 Kpa. After the screen is impacted, due to the flexibility of the organic film material, it cannot resist external force impacts well and is easily deformed, causing a strong external force to act on the OCA / LOCA film layer. However, the existing OCA / LOCA has poor impact resistance, and the impact energy cannot be absorbed or dissipated, and then is transmitted to the panel, resulting in failure phenomena such as black spots or broken bright spots on the panel. Summary of the Invention

[0005] In a first aspect of the embodiments of the present application, an adhesive composition is provided. The adhesive composition includes an adhesive matrix and a modified polymer. Wherein, the main chain of the modified polymer contains a boron-oxygen coordination and / or a boron-boron-oxygen coordination bond, and the end group and / or side chain of the modified polymer contains at least one of a hydroxyl group, an acrylate group, and a vinyl group.

[0006] It can be seen that at least one of boron-oxygen coordination bonds and boron-boron-oxygen coordination bonds is introduced into the main chain of the modified polymer of the present application. Since the boron-oxygen coordination bond or the boron-boron-oxygen coordination bond has sufficient time to break under the action of a low strain rate, it ensures that the molecular chain has flexibility and bendability at a low modulus; under the action of a high strain rate, the time scale of the molecular chain movement is much smaller than the time for the boron-oxygen coordination bond or the boron-boron-oxygen coordination bond to break, and the unbroken boron-oxygen coordination bond or boron-boron-oxygen coordination bond hinders the movement of the molecular chain, making it difficult for the molecular chain to move sufficiently to unwind, and macroscopically showing the characteristics of rigidity and elasticity. The above unique breaking and bonding behaviors of the boron-oxygen coordination bond or the boron-boron-oxygen coordination bond enable the adhesive composition to have excellent energy absorption and impact resistance performance while ensuring the bonding strength, and can absorb the energy generated by external force impact to resist the impact on the panel. In addition, by introducing active groups such as terminal hydroxyl groups, terminal acrylate groups, and terminal vinyl groups at the end groups of the modified polymer, it is beneficial to carry out cross-linking reactions with the adhesive matrix or acrylate monomers.

[0007] Combined with the first aspect, in some embodiments, the structural formula of the modified polymer is Formula (1)-Formula (2), and the structures of Formula (1)-Formula (2) are shown as follows:

[0008]

[0009] Among them, R1 and R2 in Formula (1)-Formula (2) are each independently selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups;

[0010] The adhesive matrix includes at least one of silicone resin and epoxy resin.

[0011] Combined with the first aspect, in some embodiments, the silicone resin includes polydiorganosiloxane capped with at least one of alkoxy groups, acyloxy groups, and ketoxime groups, and each organic group in the polydiorganosiloxane is independently selected from any one of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups;

[0012] The epoxy resin includes at least one of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0013] Combined with the first aspect, in some embodiments, the mass ratio of the adhesive matrix to the modified polymer is (10-80):(50-90) or (10-30):(50-90).

[0014] Combined with the first aspect, in some embodiments, the structural formula of the modified polymer is Formula (3)-Formula (6), and the structures of Formula (3)-Formula (6) are shown as follows:

[0015]

[0016] Among them, R1 and R2 in formulas (3)-(6) are each independently selected from the group consisting of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group.

[0017] In combination with the first aspect, in some embodiments, the mass ratio of the modified polymer to the acrylate monomer is (30-80):(20-50) or (30-80):(0.1-70).

[0018] In combination with the first aspect, in some embodiments, the structural formula of the modified polymer is formulas (7)-(8), and the structures of formulas (7)-(8) are shown as follows:

[0019]

[0020] Among them, R1 and R2 in formulas (7)-(8) are each independently selected from the group consisting of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group;

[0021] The adhesive matrix includes a silicone resin.

[0022] In combination with the first aspect, in some embodiments, the silicone resin includes polydiorganosiloxane, the end groups and / or side groups of the polydiorganosiloxane contain active hydrogen atoms, and each organic group in the polydiorganosiloxane is independently selected from any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group.

[0023] In combination with the first aspect, in some embodiments, the mass ratio of the adhesive matrix to the modified polymer is (10-80):(50-90).

[0024] A second aspect of the embodiments of the present application provides a method for preparing an adhesive composition. The preparation method includes mixing an adhesive matrix with a modified polymer to obtain the adhesive composition. Among them, the main chain of the modified polymer contains a boron-oxygen coordination and / or a boron-boron-oxygen coordination bond, and the end groups and / or side chains of the modified polymer contain at least one of a hydroxyl group, an acrylate group, and a vinyl group.

[0025] In combination with the second aspect, in some embodiments, the modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with boric acid and / or diboric acid. The structural formula of the modified polymer is formulas (1)-(2), and the structures of formulas (1)-(2) are shown as follows:

[0026]

[0027] Among them, R1 and R2 in Formula (1) - Formula (2) are each independently selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups;

[0028] The adhesive matrix includes at least one of a silicone resin and an epoxy resin.

[0029] It can be seen that by using boric acid and / or diboric acid to carry out a chain extension or capping reaction with hydroxyl-terminated silicone oil, the reaction is easy to proceed, the product purity is high, and it is easy to introduce boron-oxygen coordination and / or boron-oxygen coordination bonds into the molecular main chain of the hydroxyl-terminated silicone oil polymer; in addition, since the molecular chain of the formed modified polymer contains hydroxyl groups, it is easy to cross-link with the adhesive matrix.

[0030] Combined with the second aspect, in some embodiments, the hydroxyl-terminated silicone oil includes hydroxyl-terminated silicone oils with three molecular weights, and the viscosities of the hydroxyl-terminated silicone oils with the three molecular weights are respectively greater than or equal to 15000 cps, 4000 - 15000 cps, and less than or equal to 4000 cps.

[0031] Combined with the second aspect, in some embodiments, the mass fraction ratios of the hydroxyl-terminated silicone oils with viscosities respectively greater than or equal to 15000 cps, 4000 - 15000 cps, and less than or equal to 4000 cps are (30 - 60):(20 - 50):(20 - 30); the total mass fraction of the boric acid and / or diboric acid is 0.1 - 5.

[0032] It can be seen that by adding hydroxyl-terminated silicone oils with different molecular weights in different proportions, the viscosity of the formed modified polymer can be adjusted to control the viscosity of the final adhesive system and meet different viscosity requirements.

[0033] Combined with the second aspect, in some embodiments, the silicone resin includes a polydiorganosiloxane capped with at least one of an alkoxy group, an acyloxy group, and a ketoxime group, and each organic group in the polydiorganosiloxane is independently selected from any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group;

[0034] The epoxy resin includes at least one of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0035] It can be seen that the presence of the above groups in the polydiorganosiloxane is beneficial to the cross-linking reaction with the hydroxyl groups of the modified polymer.

[0036] Combined with the second aspect, in some embodiments, the mass fraction ratio of the adhesive matrix to the modified polymer is (10 - 80):(50 - 90) or (10 - 30):(50 - 90).

[0037] In combination with the second aspect, in some embodiments, the modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with boric acid and / or diboric acid to obtain an intermediate, and then reacting the intermediate with isocyanate acrylate. The structural formula of the modified polymer is Formula (3)-Formula (4), and the structures of Formula (3)-Formula (4) are shown as follows:

[0038]

[0039] Among them, R1 and R2 in Formula (3)-Formula (4) are each independently selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups;

[0040] The adhesive matrix includes acrylate monomers.

[0041] It can be seen that by using boric acid and / or diboric acid to carry out chain extension or capping reaction with the hydroxyl-terminated silicone oil, and capping the hydroxyl groups at the ends of the intermediate to introduce acrylate groups, the reaction is easy to carry out, the product purity is high, and it is easy to introduce boron-oxygen coordination and / or boron-oxygen coordination bonds into the molecular main chain of the hydroxyl-terminated silicone oil polymer, and introduce acrylate groups, which are easy to crosslink with acrylate monomers.

[0042] In combination with the second aspect, in some embodiments, the mass ratio of the modified polymer to the acrylate monomer is (30-80):(20-50).

[0043] In combination with the second aspect, in some embodiments, the modified polymer is obtained by reacting a hydroxyl-terminated acrylate polymer with boric acid and / or diboric acid to generate an intermediate, and then reacting the intermediate with a hydroxyl acrylate monomer. The structural formula of the modified polymer is Formula (5)-Formula (6), and the structures of Formula (5)-Formula (6) are shown as follows:

[0044]

[0045] Among them, R1 and R2 in Formula (5)-Formula (6) are each independently selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups, and n is an integer greater than or equal to 1;

[0046] The adhesive matrix includes acrylate monomers.

[0047] It can be seen that by using boric acid and / or diboric acid to cap the hydroxyl-terminated acrylate polymer, and using acrylic monomers to cap the hydroxyl groups at the ends of the intermediate to introduce acrylate groups, the reaction is easy to carry out, the product purity is high, and it is easy to introduce boron-oxygen coordination and / or boron-oxygen coordination bonds into the molecular main chain of the acrylate polymer, and introduce acrylate groups, which are easy to crosslink with acrylate monomers.

[0048] In combination with the second aspect, in some embodiments, the mass ratio of the modified polymer to the acrylate monomer is (30 - 80):(0.1 - 70).

[0049] In combination with the second aspect, in some embodiments, the modified polymer is obtained by reacting a hydroxy - terminated acrylate polymer with boric acid and / or diboric acid to form an intermediate, and then reacting the intermediate with vinyl silicone oil. The structural formula of the modified polymer is Formula (7) - Formula (8), and the structures of Formula (7) - Formula (8) are shown as follows:

[0050]

[0051] Among them, R1 and R2 in Formula (7) - Formula (8) are each independently selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups;

[0052] The adhesive matrix includes a silicone resin.

[0053] It can be seen that by using boric acid and / or diboric acid to carry out chain - extension or end - capping reaction with hydroxy - terminated silicone oil, and using vinyl silicone oil to cap the terminal hydroxyl groups of the intermediate, thereby introducing vinyl groups, the reaction is easy to carry out, the product purity is high, it is easy to introduce boron - oxygen coordination and / or boron - oxygen - boron coordination bonds into the molecular main chain of the hydroxy - terminated silicone oil polymer, and vinyl groups are introduced, which is easy to cross - link with the adhesive matrix of the addition - curing type silicone system.

[0054] In combination with the second aspect, in some embodiments, the silicone resin includes polydiorganosiloxane, the terminal groups and / or side groups of the polydiorganosiloxane contain active hydrogen atoms, and each organic group in the polydiorganosiloxane is independently selected from any one of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups.

[0055] In combination with the second aspect, in some embodiments, the mass ratio of the adhesive matrix to the modified polymer is (10 - 80):(50 - 90).

[0056] In the third aspect of the embodiments of the present application, an optical adhesive film is provided. The optical adhesive film is cured from the adhesive composition as described above, and the molecular chain of the optical adhesive film contains boron - oxygen coordination and / or boron - oxygen - boron coordination bonds.

[0057] In combination with the third aspect, in some embodiments, the transmittance of the optical adhesive film is greater than or equal to 90%, the haze is less than or equal to 2.0%, and the peel strength is greater than or equal to 1.0 N / in.

[0058] In a fourth aspect of the embodiments of the present application, a foldable screen is provided. The foldable screen includes a panel, and at least one substrate layer and at least one optical adhesive film stacked on the surface of the panel. One layer of the optical adhesive film is provided between the panel and the adjacent substrate layer, and between two adjacent substrate layers. The optical adhesive film is the optical adhesive film as described above.

[0059] It can be seen that boron-oxygen coordination bonds and consecutive boron-oxygen coordination bonds are introduced into the main chain of the molecules of the optical adhesive film. Due to the aforementioned unique breaking and bonding behaviors of the boron-oxygen coordination bond or the consecutive boron-oxygen coordination bond, when subjected to an impact, it can absorb energy to resist the impact on the adhesive film, enabling the optical adhesive film to have excellent impact resistance while maintaining excellent bonding performance and optical performance. The combination of multiple layers of optical adhesive film and multiple layers of substrate layer can well resist external force impacts, improve the impact resistance of the foldable screen, and reduce failure phenomena such as black spots or broken bright spots on the panel caused by external force impacts.

[0060] In a fifth aspect of the embodiments of the present application, an electronic device is provided. The electronic device includes the optical adhesive film as described above or the foldable screen as described above. Description of the Drawings

[0061] Figure 1 It is a schematic diagram of a foldable screen provided by an embodiment of the present application.

[0062] Figure 2 It is a schematic diagram of a ball-drop experiment provided by an embodiment of the present application.

[0063] Figure 3 It is a comparison chart of the ball-drop experiment results between Embodiment 7 and Comparative Example 1 of the present application.

[0064] Description of the Main Component Symbols

[0065] Foldable screen 100

[0066] Panel 10

[0067] Substrate layer 20

[0068] Optical adhesive film 30

[0069] Height h Detailed Embodiments

[0070] The embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. The data ranges involved in the present application should include the end values unless otherwise specified.

[0071] Common optical adhesives (OCA / LOCA) have poor impact resistance. After applying the optical adhesive to foldable screen electronic products, the screen of the foldable screen is prone to failure phenomena such as black spots or broken bright spots under external force impacts.

[0072] The present application provides an energy-absorbing optical adhesive composition with excellent optical properties, bonding strength and impact resistance. The adhesive composition can be used as an adhesive material for bonding different substrates in foldable screen electronic products, but is not limited thereto. Each component for synthesizing the adhesive composition is optimized, so that the adhesive composition has excellent impact resistance while maintaining excellent optical properties and bonding properties.

[0073] The adhesive composition includes an adhesive matrix and a modified polymer. Among them, the main chain of the modified polymer contains boron-oxygen coordination and / or diboron-oxygen coordination bonds, and the end groups and / or side chains of the modified polymer include at least one of hydroxyl groups, acrylate groups, and vinyl groups.

[0074] The adhesive matrix can be a base matrix of acrylate pressure-sensitive adhesive, silicone pressure-sensitive adhesive, or epoxy resin pressure-sensitive adhesive. For example, the adhesive matrix can be acrylate monomers, silicone resins, or epoxy resins.

[0075] It can be understood that in addition to the above components, the adhesive composition can also contain any necessary and non-necessary components required for conventional pressure-sensitive adhesives. For example, photoinitiators, antioxidants, and plasticizers required for acrylate pressure-sensitive adhesives, catalysts and fillers required for silicone pressure-sensitive adhesives, cross-linking agents required for epoxy resin pressure-sensitive adhesives, etc.

[0076] At least one of boron-oxygen coordination bonds and diboron-oxygen coordination bonds is introduced into the main chain of the modified polymer in the present application. Since the boron-oxygen coordination bond or diboron-oxygen coordination bond has enough time to break under the action of a low strain rate, it ensures that the molecular chain has flexibility and bendability at a low modulus; under the action of a high strain rate, the time scale of molecular chain movement is much smaller than the time for the boron-oxygen coordination bond or diboron-oxygen coordination bond to break. The unbroken boron-oxygen coordination bond or diboron-oxygen coordination bond hinders the movement of the molecular chain, making it difficult for the molecular chain to move sufficiently to unwind, and macroscopically showing the characteristics of rigidity and elasticity. The above unique breaking and bonding behaviors of the boron-oxygen coordination bond or diboron-oxygen coordination bond enable the adhesive composition to have excellent impact resistance while ensuring the optical properties and bonding properties of the optical film, and can absorb the energy generated by external force impact to resist the impact on the panel. In addition, by introducing active groups such as terminal hydroxyl groups, terminal acrylate groups, and terminal vinyl groups at the end groups of the modified polymer, it is beneficial to cross-linking reactions with acrylate monomers, silicone resins, and epoxy resins.

[0077] In the following embodiments, different modified polymers are used to modify different optical pressure-sensitive adhesive systems, endowing the corresponding optical pressure-sensitive adhesives with excellent energy absorption and impact resistance while ensuring the optical properties and bonding properties of the optical pressure-sensitive adhesives.

[0078] Example 1 (An acrylate adhesive system)

[0079] An embodiment of the present application provides an adhesive composition, which includes acrylate monomers and a modified polymer (PBDMSA). Among them, the main chain of the modified polymer (PBDMSA) contains boron-oxygen coordination bonds and / or diboron-oxygen coordination bonds, and the end groups are acrylate groups. According to whether boron-oxygen coordination bonds or diboron-oxygen coordination bonds are introduced, the structures of the modified polymers (PBDMSA1 or PBDMSA2) are respectively Formula (3)-Formula (4), and the structures of Formula (3)-Formula (4) are shown as follows:

[0080]

[0081] Among them, R1 and R2 in Formula (3)-Formula (4) are independently selected from the groups consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups.

[0082] Furthermore, the mass ratio of the modified polymer (PBDMSA1 or PBDMSA2) to the acrylate monomer is (30-80):(20-50).

[0083] Furthermore, the adhesive composition further includes a photoinitiator, and the modified polymer (PBDMSA1 or PBDMSA2) and the acrylate monomer undergo a polymerization reaction and cure under the action of the photoinitiator. In this embodiment, the photoinitiator includes but is not limited to photoinitiators required for optical acrylate pressure-sensitive adhesive systems such as Model 184 and TPO.

[0084] Furthermore, the adhesive composition further includes an antioxidant and a plasticizer. In this embodiment, the antioxidant includes but is not limited to antioxidants required for optical acrylate pressure-sensitive adhesive systems such as Model 1010 and DNP, and the plasticizer includes but is not limited to plasticizers required for optical acrylate pressure-sensitive adhesive systems such as DMP and DOP.

[0085] Furthermore, the solvent of the adhesive composition includes but is not limited to methanol, toluene, tetrahydrofuran (THF), ethyl acetate, etc.

[0086] It can be understood that in addition to the above components, the adhesive composition may further contain any necessary and non-necessary components required for a conventional optical acrylate pressure-sensitive adhesive system.

[0087] In this embodiment, at least one of boron-oxygen coordination bonds and boron-oxygen coordination bonds is introduced into the molecular main chain of the optical acrylate pressure-sensitive adhesive. Due to the above unique fracture and bonding behaviors of the boron-oxygen coordination bond or the boron-oxygen coordination bond, the optical acrylate pressure-sensitive adhesive has excellent energy absorption and impact resistance performance on the premise of ensuring the optical performance and bonding performance of the optical adhesive film, and can absorb the energy generated by external force impact to resist the impact on the panel. In addition, by introducing terminal acrylate groups at the end groups of the modified polymer (PBDMSA1 or PBDMSA2), it is beneficial to cross-link with acrylate monomers.

[0088] The preparation method of the above adhesive composition specifically includes the following steps:

[0089] Step S11: Prepare the modified polymer (PBDMSA1 or PBDMSA2).

[0090] First, a modified polymer (PBDMS1 or PBDMS2) modified with boron-oxygen bonds is generated through the chain extension reaction of terminal hydroxyl silicone oil with boric acid and / or diboric acid. The structural formulas of the modified polymers (PBDMS1 or PBDMS2) are respectively Formula (1)-Formula (2), and the structures of Formula (1)-Formula (2) are shown as follows:

[0091]

[0092]

[0093] Among them, R1 and R2 in Formula (1)-Formula (2) are independently selected from the groups in the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups. Using boric acid and / or diboric acid to carry out chain extension or capping reaction with terminal hydroxyl silicone oil, the reaction is easy to carry out, the product purity is high, it is easy to introduce boron-oxygen coordination and / or boron-oxygen coordination bonds into the molecular main chain of the terminal hydroxyl silicone oil polymer, and at the same time introduce hydroxyl groups into the product molecular chain, which is convenient for subsequent introduction of acrylate groups.

[0094] Then, the modified polymer (PBDMS1 or PBDMS2) is capped with isocyanate acrylate (such as isocyanate ethyl acrylate AOI) under the action of an organotin catalyst to obtain the modified polymer (PBDMSA1 or PBDMSA2).

[0095] The reaction process of synthesizing the adhesive matrix (PBDMSA1) using boric acid is shown in the following reaction formula (I)-reaction formula (II):

[0096]

[0097] The reaction process for synthesizing the modified polymer (PBDMSA2) using diboric acid is as shown in Reaction Formula (III) - Reaction Formula (IV) below:

[0098]

[0099] In Reaction Formulas (I) - (IV), R1 and R2 are each independently selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups.

[0100] Furthermore, the hydroxyl-terminated silicone oil is a combination of hydroxyl-terminated silicone oils with different molecular weights, including high molecular weight hydroxyl-terminated silicone oil with a viscosity ≥ 15000 cps, medium molecular weight hydroxyl-terminated silicone oil with a viscosity of 4000 - 15000 cps, and low molecular weight hydroxyl-terminated silicone oil with a viscosity ≤ 4000 cps. The mass fractions of the three are 30 - 60, 20 - 50, and 20 - 30 respectively. The average molecular weight and viscosity of the modified polymer (PBDMS1 or PBDMS2) can be regulated by adjusting the content of hydroxyl-terminated silicone oils with different molecular weights. The mass fraction of boric acid / diboric acid is 0.1 - 5.

[0101] Furthermore, the organotin catalyst includes but is not limited to dibutyltin dilaurate (DBTDL).

[0102] Furthermore, the solvents in the reaction process include but are not limited to methanol, toluene, THF, ethyl acetate, etc.

[0103] It can be understood that in other embodiments, the hydroxyl-terminated silicone oil can also react with boric acid and diboric acid simultaneously to form a modified polymer (PBDMS) containing both boron-oxygen coordination bonds and boron-boron-oxygen coordination bonds in the molecular chain.

[0104] Step S12: Mix the above modified polymer (PBDMSA1 or PBDMSA2) with acrylate monomers to form the adhesive composition.

[0105] Furthermore, the adhesive composition also includes a photoinitiator, an antioxidant, and a plasticizer. It can be understood that in addition to the above components, the adhesive composition can also contain any necessary and non-necessary components required for a conventional optical acrylate pressure-sensitive adhesive system.

[0106] When the above adhesive composition is used as an optical adhesive film, the optical adhesive film is cured under light, specifically UV light curing. Among them, the acrylate groups on the modified polymer (PBDMSA1 or PBDMSA2) can undergo a crosslinking reaction with acrylate monomers, thereby generating a crosslinked and cured optical adhesive film. The molecular chain of this optical adhesive film contains boron-oxygen coordination and / or boron-boron-oxygen coordination bonds.

[0107] In this embodiment, the transmittance of the optical adhesive film is greater than or equal to 90%, the haze is less than or equal to 2.0%, and the peel strength is greater than or equal to 1.0 N / in, which can meet the requirements of optical performance and bonding strength of the optical acrylate adhesive. In addition, the bonding strength of the optical adhesive film can be regulated by adjusting the molecular weight of the modified polymer (PBDMSA1 or PBDMSA2) and the degree of crosslinking curing to meet different requirements.

[0108] Example 2 (Another acrylate adhesive system)

[0109] Another embodiment of the present application provides an adhesive composition, which is different from the previous embodiment in that: the structure of the modified polymer (B-PAA) used in this embodiment for the modified acrylate adhesive system is different from the modified polymer (PBDMSA) used in the previous embodiment for the modified acrylate adhesive system. In this embodiment, the main chain of the modified polymer (B-PAA) contains a boron-oxygen coordination bond / boron-linked oxygen coordination bond, and at the same time, the end group and / or side chain of the modified polymer (B-PAA) contains an acrylate group.

[0110] Furthermore, the structure of the modified polymer (B-PAA1 or B-PAA2) is Formula (5)-Formula (6), and the structures of Formula (5)-Formula (6) are shown as follows:

[0111]

[0112] Among them, R1 and R2 in Formula (5)-Formula (6) are independently selected from the groups consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups, and n is an integer greater than or equal to 1.

[0113] In this embodiment, at least one of a boron-oxygen coordination bond and a boron-linked oxygen coordination bond is introduced into the molecular main chain of the optical acrylate pressure-sensitive adhesive. Due to the above unique fracture and bonding behaviors of the boron-oxygen coordination bond or the boron-linked oxygen coordination bond, the optical acrylate pressure-sensitive adhesive has excellent energy-absorbing and impact-resistant properties on the premise of ensuring the optical performance and bonding performance of the optical adhesive film, and can absorb the energy generated by external force impact to resist the influence of the impact on the panel. In addition, by introducing an acrylate group at the end group of the modified polymer (B-PAA), it is beneficial to carry out a crosslinking reaction with acrylate monomers.

[0114] The preparation method of the adhesive composition in this embodiment specifically includes the following steps:

[0115] Step S21: Preparation of the modified polymer (B-PAA1 or B-PAA2).

[0116] The terminal - hydroxyl acrylate polymer is chain - extended or capped with boric acid or diboric acid to generate an intermediate, and then the intermediate product is capped with hydroxyethyl acrylate to generate the modified acrylate polymer.

[0117] The reaction process for generating the modified polymer (B - PAA1) using boric acid is shown in the following Reaction Formula (V) - Formula (VI):

[0118]

[0119] The reaction process for generating the modified polymer (B - PAA2) using diboric acid is shown in the following Reaction Formula (VII) - Formula (VIII):

[0120]

[0121] In Formula (V) - Formula (VIII), R1 is selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups; n is an integer greater than or equal to 1.

[0122] Further, the terminal - hydroxyl acrylate polymer includes, but is not limited to, terminal - hydroxyl polybutyl acrylate, terminal - hydroxyl polyisooctyl acrylate, terminal - hydroxyl polybutadiene, terminal - hydroxyl polyisoprene, etc. In this embodiment, the mass fraction of the terminal - hydroxyl acrylate polymer is 40 - 80.

[0123] Further, the hydroxy - acrylic monomer includes, but is not limited to, hydroxyethyl acrylate, hydroxybutyl acrylate, etc. In this embodiment, the hydroxy - acrylic monomer is hydroxyethyl acrylate, and the mass fraction is 5 - 40.

[0124] Further, the mass fraction of the boric acid or diboric acid is 0.1 - 20.

[0125] Step S22: Mix the above - mentioned modified polymer (B - PAA1 or B - PAA2) with acrylate monomers to form the adhesive composition.

[0126] Further, the mass - fraction ratio of the modified polymer (B - PAA1 or B - PAA2) to the acrylate monomers is (30 - 80):(0.1 - 70).

[0127] Further, the adhesive composition also includes a photo - initiator, an antioxidant, and a plasticizer. It can be understood that in addition to the above components, the adhesive composition may also contain any necessary and non - necessary components required for a conventional optical acrylate pressure - sensitive adhesive system.

[0128] When the above-mentioned adhesive composition is used as an optical adhesive film, the optical adhesive film is cured under light by the above-mentioned adhesive composition, specifically by UV light curing. Among them, the acrylate groups on the modified polymer (B-PAA1 or B-PAA2) can undergo a cross-linking reaction with acrylate monomers, thereby generating a cross-linked and cured optical adhesive film, and the molecular chain of the optical adhesive film contains boron-oxygen coordination and / or boron-boron-oxygen coordination bonds.

[0129] In this embodiment, the transmittance of the optical adhesive film is greater than or equal to 90%, the haze is less than or equal to 2.0%, and the peel strength is greater than or equal to 1.0 N / in, which can meet the requirements of optical acrylate adhesives for optical properties and bonding strength. In addition, the bonding strength of the optical adhesive film can also be regulated by adjusting the molecular weight of the modified polymer (PBDMSA1 or PBDMSA2) and the degree of cross-linking curing to meet different requirements.

[0130] Example 3 (an organosilicon adhesive system)

[0131] Another embodiment of the present application provides an adhesive composition, which includes the modified polymers (PBDMS1 and / or PBDMS2) in the foregoing Example 1 and a silicone resin of a condensation-curing type optical organosilicon pressure-sensitive adhesive system.

[0132] Further, the silicone resin includes a polydiorganosiloxane capped with at least one of an alkoxy group, an acyloxy group, and a ketoxime group, and each organo group in the polydiorganosiloxane is independently selected from any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group. In this embodiment, the structure of the polydiorganosiloxane is shown in the following formula (9):

[0133]

[0134] Among them, n is an integer greater than or equal to 1.

[0135] Further, the mass ratio of the polydiorganosiloxane to the modified polymer (PBDMS1 and / or PBDMS2) is (10-80):(50-90). In this embodiment, the elastic modulus of the polydiorganosiloxane is less than or equal to 10 Mpa, the light transmittance is greater than or equal to 90%, and the haze is less than or equal to 5.0%.

[0136] Further, the adhesive composition further includes a catalyst and a nano-silica filler. The catalyst includes, but is not limited to, a platinum catalyst.

[0137] Further, the adhesive composition further includes a nano-silica filler.

[0138] It is understandable that in addition to the above components, the adhesive composition may further contain any necessary and non-necessary components required for a conventional condensation-curing type organosilicon pressure-sensitive adhesive system.

[0139] The above adhesive composition cures under humid conditions to form an optical adhesive film. Among them, the hydroxyl groups on the modified polymers (PBDMS1 and / or PBDMS2) can undergo a condensation reaction with the alkoxy groups on the polydiorganosiloxane under room temperature and humid conditions, and finally form a crosslinked and cured optical adhesive film. The molecular chain of this optical adhesive film contains boron-oxygen coordination and / or boron-oxygen coordination bonds.

[0140] Specifically, the crosslinking reaction process and structural formula of the modified polymers (PBDMS1 and / or PBDMS2) and the polydiorganosiloxane shown in formula (9) are as shown in the following reaction formula (IX):

[0141]

[0142] Among them, n is an integer greater than or equal to 1.

[0143] In this embodiment, the transmittance of the optical adhesive film is greater than or equal to 90%, the haze is less than or equal to 2.0%, and the peel strength is greater than or equal to 1.0 N / in, which can meet the requirements of optical organosilicon pressure-sensitive adhesives for optical properties and bonding strength. In addition, the bonding strength of the optical adhesive film can also be regulated by adjusting the molecular weight of the modified polymer (PBDMS1 or PBDMS2) and the degree of crosslinking and curing to meet different requirements.

[0144] This embodiment is a modified optical organosilicon pressure-sensitive adhesive system, which introduces at least one of boron-oxygen coordination bonds and boron-oxygen coordination bonds into the main molecular chain of the organosilicon pressure-sensitive adhesive. Due to the above unique fracture and bonding behaviors of boron-oxygen coordination bonds or boron-oxygen coordination bonds, the optical organosilicon pressure-sensitive adhesive has excellent buffering, energy absorption and impact resistance properties on the premise of ensuring the optical properties and bonding properties of the optical adhesive film, and can absorb the energy generated by external force impact to resist the impact on the panel. In addition, the modified polymers (PBDMS1 and / or PBDMS2) containing boron-oxygen coordination bonds or boron-oxygen coordination bonds are cured and formed into a new structure polymer through a condensation-curing type silicone resin, avoiding the defects that the modified polymers (PBDMS1 and / or PBDMS2) containing boron-oxygen coordination bonds or boron-oxygen coordination bonds are prone to creep and flow and have no peel strength.

[0145] Example 4 (Another organosilicon adhesive system)

[0146] Another embodiment of the present application provides an adhesive composition, which includes a modified polymer (PBDMSC) and a siloxane resin of an addition-curable optical silicone pressure-sensitive adhesive system. The main chain of the modified polymer (PBDMSC) contains boron-oxygen coordination and / or boron-oxygen coordination bonds, and the end groups and / or side chains of the modified polymer (PBDMSC) contain vinyl groups.

[0147] The structural formulas of the modified polymers (PBDMSC1 or PBDMSC2) are shown in Formulas (7)-(8) respectively:

[0148]

[0149] Among them, R1 and R2 in Formulas (7)-(8) are each independently selected from the group consisting of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups.

[0150] Further, the siloxane resin includes polydiorganosiloxane, the end groups and / or side groups of the polydiorganosiloxane contain active hydrogen atoms, and each organic group in the polydiorganosiloxane is independently selected from any one of alkyl groups, alkoxy groups, alkenyl groups, cycloalkyl groups, and aryl groups. In this embodiment, the structure of the polydiorganosiloxane is shown in the following Formula (10):

[0151]

[0152] Further, the mass ratio of the polydiorganosiloxane to the modified polymer (PBDMSC1 and / or PBDMSC2) is (10-80):(50-90). In this embodiment, the elastic modulus of the polydiorganosiloxane is less than or equal to 10 Mpa, the light transmittance is greater than or equal to 90%, and the haze is less than or equal to 5.0%.

[0153] Further, the adhesive composition further includes a catalyst and nano-silica filler.

[0154] It can be understood that in addition to the above components, the adhesive composition may further contain any necessary and non-necessary components required for a conventional addition-curable optical silicone pressure-sensitive adhesive system.

[0155] The preparation method of the adhesive composition in this embodiment specifically includes the following steps:

[0156] Step S41: Preparation of the modified polymer (PBDMSC1 or PBDMSC2).

[0157] The modified polymer (PBDMSC1 or PBDMSC2) is obtained by end-capping the modified polymer (PBDMS1 or PBDMS2) in the foregoing Example 1 with vinyl silicone oil. The structure of the vinyl silicone oil is shown in the following formula (11):

[0158]

[0159] The reaction formula for the reaction of the modified polymer (PBDMS1 or PBDMS2) prepared in the foregoing example with vinyl silicone oil is shown in the following formula (X):

[0160]

[0161] Step S42: Mix the above-mentioned modified polymer (PBDMSC1 and / or PBDMSC2) with the siloxane resin shown in formula (10) and other components to form the adhesive composition.

[0162] The above-mentioned adhesive composition cures under heating conditions to form an optical adhesive film. Among them, the vinyl groups on the modified polymer (PBDMSC1 or PBDMSC2) can undergo addition polymerization reaction with the active hydrogen atoms on the polydiorganosiloxane under heating conditions, and finally a crosslinked and cured optical adhesive film is formed. The molecular chain of the optical adhesive film contains boron-oxygen coordination and / or boron-oxygen coordination bonds.

[0163] Specifically, the crosslinking reaction process and structural formula of the modified polymer (PBDMS1 and / or PBDMS2) and the polydiorganosiloxane shown in formula (10) are shown in the following reaction formula (XI):

[0164]

[0165] In this example, the transmittance of the optical adhesive film is greater than or equal to 90%, the haze is less than or equal to 2.0%, and the peel strength is greater than or equal to 1.0 N / in, which can meet the requirements of optical silicone pressure-sensitive adhesives for optical properties and bonding strength. In addition, the bonding strength of the optical adhesive film can also be regulated by adjusting the molecular weight of the modified polymer (PBDMS1 and / or PBDMS2) and the degree of crosslinking and curing to meet different requirements.

[0166] This embodiment is another modified optical silicone pressure-sensitive adhesive system, in which at least one of boron-oxygen coordination bonds and boron-boron-oxygen coordination bonds is introduced into the molecular main chain of the silicone pressure-sensitive adhesive. Due to the above unique fracture and bonding behaviors of the boron-oxygen coordination bond or boron-boron-oxygen coordination bond, the optical silicone pressure-sensitive adhesive has excellent buffering, energy absorption and impact resistance properties on the premise of ensuring the optical properties and bonding properties of the optical adhesive film, and can absorb the energy generated by external force impact to resist the impact on the panel. In addition, the modified polymers (PBDMSC1 and / or PBDMSC2) can be cured and formed by an addition-curing silicone resin to form a new structural polymer, avoiding the defects that the boron-containing modified polymers (PBDMSC1 and / or PBDMSC2) are prone to creep and flow and have no peel strength.

[0167] Example 5 (Epoxy Resin Adhesive System)

[0168] Another embodiment of the present application provides an adhesive composition, which includes the modified polymers (PBDMS1 and / or PBDMS2) in the aforementioned Example 1 and an epoxy resin.

[0169] Further, the epoxy resin can be any epoxy resin, specifically at least one of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0170] Further, the adhesive composition further includes a crosslinking agent, and the tertiary amine crosslinking agent includes but is not limited to acid anhydrides, amines, dicyandiamide, etc.

[0171] Further, the mass ratio of the epoxy resin to the modified polymer is (10-30):(30-60).

[0172] It can be understood that in addition to the above components, the adhesive composition may further contain any necessary and non-necessary components required for a conventional optical epoxy resin pressure-sensitive adhesive system.

[0173] This embodiment also provides an optical adhesive film, which is formed by curing the above adhesive composition under heating conditions. The hydroxyl groups on the modified polymers (PBDMS1 or PBDMS2) can undergo a polymerization reaction with the epoxy groups of the epoxy resin under heating conditions, and finally a crosslinked and cured optical adhesive film is formed. The molecular chain of this optical adhesive film contains boron-oxygen coordination and / or boron-boron-oxygen coordination bonds.

[0174] Specifically, the crosslinking reaction process and structural formula between the modified polymers (PBDMS1 or PBDMS2) and the epoxy groups of the epoxy resin are shown in Reaction Formula (XII)-Reaction Formula (XIII) as follows:

[0175]

[0176] Among them, R in Reaction Formula (XII) - Reaction Formula (XIII) are respectively residues of bisphenol A or bisphenol F; each n is an integer greater than or equal to 1. In this embodiment, R1 and R2 in the modified polymer (PBDMS1 or PBDMS2) are both methyl groups.

[0177] It can be understood that the epoxy resin adhesive product obtained from Reaction Formula (XII) - Reaction Formula (XIII) has a linear structure and is in a liquid state. Other fillers (such as nano-silica, plasticizers, etc.) can also be added and further crosslinked and cured under the action of curing agents such as acid anhydrides or amines to form a crosslinked network structure.

[0178] In this embodiment, the transmittance of the optical adhesive film is greater than or equal to 90%, the haze is less than or equal to 2.0%, and the peel strength is greater than or equal to 1.0 N / in, which can meet the requirements of the optical epoxy resin pressure-sensitive adhesive for optical properties and bonding strength. In addition, the bonding strength of the optical adhesive film can also be regulated by adjusting the molecular weight of the modified polymer (PBDMS1 and / or PBDMS2) and the degree of crosslinking and curing to meet different requirements.

[0179] This embodiment is a modified optical epoxy resin pressure-sensitive adhesive system, in which at least one of boron-oxygen coordination bonds and boron-boron-oxygen coordination bonds is introduced into the main chain of the molecule of the epoxy resin pressure-sensitive adhesive. Due to the unique breaking and bonding behaviors of the boron-oxygen coordination bond or boron-boron-oxygen coordination bond, the optical epoxy resin pressure-sensitive adhesive has excellent buffering, energy absorption and impact resistance properties on the premise of ensuring the optical properties and bonding properties of the optical adhesive film, and can absorb the energy generated by external force impact to resist the impact on the panel.

[0180] Please refer to Figure 1 , this application also provides a folding screen 100, which includes a panel 10, a multi-layer substrate layer 20 laminated on the front surface of the panel 10, and an optical adhesive film 30. An optical adhesive film 30 is provided between the panel 10 and the adjacent substrate layer 20, and between adjacent two substrate layers 20. The optical adhesive film 30 is cured by using any one of the foregoing adhesive compositions. According to the foregoing different adhesive compositions, different curing methods are adopted.

[0181] Furthermore, the folding screen 100 can be prepared by the following two processes.

[0182] The first process is as follows: Prepare any one of the aforementioned adhesive compositions, and perform vacuum degassing on the adhesive composition; coat the degassed adhesive composition on the substrate layer 20 and cure it to obtain an optical adhesive film 30; cover the surface of the optical adhesive film 30 with a release film to prepare a single-sided optical tape, and die-cut the single-sided optical tape; after removing the release film from the die-cut single-sided optical tape, attach it to the front side of the panel 10. If multiple substrate layers 20 need to be attached, the single-sided optical tapes can be attached in sequence and degassed again to obtain the folding screen 100. It can be understood that when multiple substrate layers 20 need to be attached, the two surfaces of the intermediate substrate layer 20 can be coated with the adhesive composition to prepare a double-sided optical tape. It can also be understood that different numbers of layers and different thicknesses of the optical adhesive film 30 can be designed according to the actual impact resistance requirements of the product. It can also be understood that when multiple substrate layers 20 need to be attached, the folding screen 100 can also include a conventional optical adhesive film.

[0183] The second process is as follows: Prepare any one of the aforementioned adhesive compositions, and perform vacuum degassing on the adhesive composition; dot-coat or spray the degassed adhesive composition on the front side of the panel 10 to form an uncured adhesive film (not shown in the figure), then attach the substrate layer 20 to the surface of the uncured adhesive film, perform vacuum degassing again, and cure it after degassing to obtain the optical adhesive film 30. If multiple substrate layers 20 need to be attached, the above method can be repeated to form multiple layers of optical adhesive film 30 in sequence, thereby obtaining the folding screen 100. This process is a process of laminating first and then curing, which can be applied to the case of local bonding, without the need for large-area adhesive application, and the operation is more flexible.

[0184] Further, the material of the substrate layer 20 includes but is not limited to PI or PET.

[0185] Borate coordination bonds and diborate coordination bonds are introduced into the main chain of the molecules of the optical adhesive film 30. Due to the unique fracture and bonding behavior of the boron-oxygen coordination bond or diboron-oxygen coordination bond, when subjected to an impact, it can absorb energy to resist the impact on the adhesive film, so that the optical adhesive film 30 has excellent impact resistance while maintaining excellent bonding performance and optical performance. The combination of multiple layers of optical adhesive film 30 and multiple layers of substrate layer 20 can well resist external force impacts, improve the impact resistance of the folding screen, and reduce the failure phenomena such as black spots or broken bright spots on the panel 10 caused by external force impacts.

[0186] The embodiments of the present application will be further described below through specific examples.

[0187] Synthesis Example 1

[0188] Preparation of a borate bond-modified hydroxyl-terminated silicone oil polymer (PBDMS1 or PBDMS2):

[0189] The raw material formula for synthesizing the hydroxyl-terminated silicone oil polymer (PBDMS1 or PBDMS2) modified by boron-oxygen bonds is shown in Table 1.

[0190] Table 1

[0191]

[0192] Add the formula in Table 1 into a reaction vessel (such as a beaker, flask, reactor, etc.) according to the corresponding ratio. At room temperature, stir at a speed of 5 - 5000 rpm for ≥ 2 h, and the vacuum degree during stirring is -0.08 Mpa to -0.095 Mpa. Stir until it is evenly mixed (specifically manifested as evenly dispersed, no particle sedimentation, no phase separation). Then raise the reaction environment temperature to 50 - 100 °C, maintain the stirring speed and vacuum degree, and the reaction time is ≥ 4 h to obtain PBDMS1 or PBDMS2.

[0193] Synthesis Example Two

[0194] Preparation of a modified silicone oil polymer (PBDMSA1 or PBDMSA2):

[0195] The raw material formula for synthesizing the modified silicone oil polymer (PBDMSA1 or PBDMSA2) is shown in Table 2.

[0196] Table 2

[0197] Raw material Typical type / grade Parts by mass PBDMS1 or PBDMS2 Synthesis Example 1 40-70 Ethyl isocyanate acrylate AOI 15-25 Solvent Methanol, toluene, THF, ethyl acetate, etc. 5-40 Organotin catalyst DBTDL, dibutyltin dilaurate, etc. 0-5 Polymerization inhibitor Hydroquinone HQ, benzoquinone PBQ, etc. 0-1

[0198] Add PBDMS1 or PBDMS2, solvent, catalyst, inhibitor in Table 2 into a reaction vessel (beaker, flask, reactor, etc.), pass nitrogen, stir the raw materials evenly at a speed of 5 - 5000 rpm and raise the temperature to 60 - 100 °C, and the stirring time is ≥ 1 h. Then add ethyl isocyanate acrylate and organotin catalyst according to the ratio to start the reaction, ensure the reaction time is ≥ 1 h, then stop passing nitrogen, evacuate (vacuum degree -0.08 Mpa to -0.095 Mpa), stir at a speed of 5 - 5000 rpm for more than 2 h until the solvent volatilizes completely, and filter to obtain PBDMSA1 or PBDMSA2.

[0199] Synthesis Example Three

[0200] Preparation of a modified acrylate polymer (B-PAA1 or B-PAA2):

[0201] The raw material formula for synthesizing the modified acrylate polymer (B-PAA1 or B-PAA2) is shown in Table 3.

[0202] Table 3

[0203]

[0204] Add the formulations in Table 3 into a reaction vessel (such as a beaker, flask, reaction kettle, etc.) according to the corresponding ratios. At room temperature, stir at a speed of 5 - 5000 rpm for ≥ 2 h, and during the stirring process, the vacuum degree is -0.08 Mpa to -0.095 Mpa. Until the mixture is homogeneous (specifically manifested as uniform dispersion, no particle sedimentation, no phase separation), raise the reaction environment temperature to 60 - 100 °C, maintain the stirring speed and vacuum degree, and the reaction time is ≥ 4 h. Then add hydroxyethyl acrylate or hydroxybutyl acrylate according to the ratio, maintain the reaction temperature at 60 - 100 °C, the stirring speed at 5 - 5000 rpm, the time ≥ 4 h, and the vacuum degree at -0.08 Mpa to -0.095 Mpa until the reaction is completed to obtain a modified acrylate polymer (B-PAA1 or B-PAA2).

[0205] Synthesis Example Four

[0206] Preparation of a modified silicone oil polymer (PBDMSC1 or PBDMSC2):

[0207] The raw material formulations for synthesizing the modified silicone oil polymer (PBDMSC1 or PBDMSC2) are shown in Table 4.

[0208] Table 4

[0209] Raw material Typical type / grade Parts by mass PBDMS1 or PBDMS2 Synthesis Example 1 40-70 Vinyl silicone oil Formula 10 15-25 Solvent Methanol, toluene, THF, ethyl acetate, etc. 5-40 Catalyst Lithium hydroxide 0-5

[0210] Add PBDMS1 or PBDMS2, vinyl silicone oil, solvent, and catalyst in Table 4 into a reaction vessel (beaker, flask, reaction kettle, etc.) according to the ratios, and react at room temperature to obtain PBDMSC1 or PBDMSC2.

[0211] Example One

[0212] Preparation of an acrylate-based adhesive composition:

[0213] The raw material formulations for synthesizing the adhesive composition are shown in Table 5.

[0214] Table 5

[0215] Raw material Typical type / grade Parts by mass PBDMSA1 and / or PBDMSA2 Synthesis Example 2 30-80 Acrylate monomer Butyl acrylate, lauryl acrylate, etc. 20-50 Photoinitiator 184, TPO, etc. 0-5 Antioxidant Antioxidant 1010, antioxidant DNP, etc. 0-5 Plasticizer DMP, DOP, etc. 0-30

[0216] Mix the above PBDMSA1 and / or PBDMSA2 with acrylate monomers, photoinitiator, antioxidant, and plasticizer evenly according to the above ratios to obtain an acrylate-based adhesive composition for standby use.

[0217] Example Two

[0218] Preparation of another acrylate-based adhesive composition:

[0219] The raw material formulations for synthesizing another acrylate-based adhesive composition are shown in Table 6.

[0220] Table 6

[0221] Raw material Typical type / grade Parts by mass B-PAA1 and / or B-PAA2 Synthesis Example 3 30-80 Acrylate monomer Butyl acrylate, lauryl acrylate, etc. 0-70 Photoinitiator 184, TPO, etc. 0-5 Antioxidant Antioxidant 1010, antioxidant DNP, etc. 0-5 Plasticizer DMP, DOP, etc. 0-50

[0222] Mix the above B-PAA1 and / or B-PAA2 with acrylate monomers, photoinitiators, antioxidants, and plasticizers in the above proportions and mix well to obtain an adhesive composition of the acrylate system for later use.

[0223] Example 3

[0224] (1) Preparation of an adhesive composition of an organosilicon system:

[0225] The raw material formula for preparing the adhesive composition of the organosilicon system is shown in Table 7.

[0226] Table 7

[0227]

[0228] Mix PBDMS1 and / or PBDMS2 prepared in Example 1 in Table 7, condensation-curing organosilicon adhesives, nano-silica fillers, catalysts, and solvents in the above proportions and mix well to obtain an adhesive composition of an organosilicon system.

[0229] (2) Preparation of a liquid optical curing adhesive bond of an organosilicon system:

[0230] Then add the adhesive composition obtained in (1) to a reaction vessel (beaker, flask, reaction kettle, etc.), evacuate, stir the raw materials evenly at a rotation speed of 5 - 5000 rpm and heat to ≥60 °C. During the stirring process, the vacuum degree ≥ -200 kPa and the reaction time ≥ 1 h to obtain another liquid optical adhesive of the organosilicon system for later use.

[0231] Example 4

[0232] (1) Preparation of another adhesive composition of an organosilicon system:

[0233] The raw material formula for preparing another adhesive composition of the organosilicon system is shown in Table 8.

[0234] Table 8

[0235]

[0236] Mix PBDMSC1 and / or PBDMSC2 in Table 8 with polydimethylsiloxane containing hydrogen atoms in the end group, nano-silica fillers, catalysts, and solvents in proportion and mix well to obtain another adhesive composition of the organosilicon system.

[0237] (2) Preparation of a liquid optical curing adhesive bonded with another silicone system:

[0238] Then add the adhesive composition obtained in (1) into a reaction vessel (beaker, flask, reaction kettle, etc.), evacuate the air, stir the raw materials evenly at a speed of 5 - 5000 rpm and heat up to ≥60 °C. During the stirring process, the vacuum degree ≥ - 200 kPa and the reaction time ≥ 1 h to obtain another liquid optical curing adhesive bonded with a silicone system for later use.

[0239] Example Five

[0240] (1) Preparation of an adhesive composition of an epoxy resin system:

[0241] The raw material formula for preparing the adhesive composition of the epoxy resin system is shown in Table 9.

[0242] Table 9

[0243]

[0244] Mix the PBDMS1 and / or PBDMS2, epoxy resin and cross - linker synthesized in Example 1 in Table 9 evenly to obtain the adhesive composition of the epoxy resin system.

[0245] (2) Preparation of a liquid optical adhesive of an epoxy resin system:

[0246] Add the adhesive composition of the epoxy resin system prepared in (1) into a reaction vessel (beaker, flask, reaction kettle, etc.), evacuate the air, stir the raw materials evenly at a speed of 5 - 5000 rpm and heat up to ≥60 °C. During the stirring process, the vacuum degree ≥ - 200 kPa and the reaction time ≥ 1 h to obtain the liquid optical adhesive of the epoxy resin system for later use.

[0247] (3) Preparation of a cross - linked network epoxy resin adhesive:

[0248] Mix and further cure the linear epoxy resin adhesive prepared in (2) according to the formula shown in Table 10 below to obtain a cross - linked network adhesive.

[0249] Table 10

[0250]

[0251] A folding screen:

[0252] Stack two PI substrates and two optical adhesive films on the front side of the panel. The two optical adhesive films are respectively located between the panel and the PI substrate and between the two PI substrates. Among them, the thickness of the PI substrate is 50 μm, and the thickness of the optical adhesive film is 50 μm. The optical adhesive film is the optical adhesive film of the boron-oxygen coordination bond modified silicone adhesive system prepared in Example 3 of this application.

[0253] Comparative Example 1

[0254] An existing folding screen:

[0255] Stack two PI substrates and two optical adhesive films on the front side of the panel. The two optical adhesive films are respectively located between the panel and the PI substrate and between the two PI substrates. Among them, the thickness of the PI substrate is 50 μm, and the thickness of the optical adhesive film is 50 μm. The optical adhesive film is the optical adhesive film of the existing silicone adhesive system.

[0256] Use the boron-oxygen coordination bond modified silicone adhesive prepared in Example 3 of this application to prepare a folding screen and conduct a steel ball impact test. The weight of the steel ball is 32 g and the diameter is 20 mm. The steel ball test is as Figure 2 shown. Test the failure height at which bright broken spots appear under the impact of the steel ball for the two folding screens. The test results are as Figure 3 shown. The lowest failure height at which bright broken spots appear for the folding screen of Comparative Example 1 is 73 cm, and the lowest failure height at which bright broken spots appear for the folding screen of Example 6 of this application is 91 cm, showing a significant improvement compared to Comparative Example 1. It shows that boron-oxygen coordination bonds and boron-oxygen coordination bonds are introduced into the main chain of the molecules of the optical adhesive film in this application. Due to the unique fracture and bonding behavior of the boron-oxygen coordination bond or boron-oxygen coordination bond, when subjected to an impact, it can absorb energy to resist the impact on the adhesive film, so that the optical adhesive film has excellent impact resistance while maintaining excellent bonding performance and optical performance. The combination of multiple layers of optical adhesive films and multiple layers of substrate layers can well resist external force impacts, improve the impact resistance of the folding screen, and reduce failure phenomena such as black spots or bright broken spots on the panel caused by external force impacts.

[0257] It should be noted that the above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed in this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application; without conflict, the implementation manners of this application and the features in the implementation manners can be combined with each other. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. An adhesive composition, characterized in that, Comprising: An adhesive matrix, the adhesive matrix comprising at least one of a silicone resin and an epoxy resin; And A modified polymer, Wherein, the main chain of the modified polymer contains a boron-oxygen coordination and / or a linked boron-oxygen coordination bond, and the end group and / or side chain of the modified polymer contains a hydroxyl group.

2. The adhesive composition according to claim 1, characterized in that, The modified polymer is obtained by a chain extension reaction of a hydroxyl-terminated silicone oil with boric acid and / or diboric acid.

3. The adhesive composition according to claim 2, wherein The structural formula of the modified polymer is Formula (1), and the structure of Formula (1) is shown as follows: Wherein, R1 in Formula (1) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (1) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; Or, the structural formula of the modified polymer is Formula (2), and the structure of Formula (2) is shown as follows: Wherein, R1 in Formula (2) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (2) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group.

4. The adhesive composition according to claim 2 or 3, characterized in that, The silicone resin includes a polydiorganosiloxane terminated with at least one of an alkoxy group, an acyloxy group, and a ketoxime group, and each organic group in the polydiorganosiloxane includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; The epoxy resin includes at least one of a bisphenol A epoxy resin and a bisphenol F epoxy resin.

5. An adhesive composition, characterized in that, Comprising: An adhesive matrix, the adhesive matrix comprising an acrylate monomer; A modified polymer, the main chain of the modified polymer contains a boron-oxygen coordination and / or a linked boron-oxygen coordination bond, and the end group and / or side chain of the modified polymer contains an acrylate group; The modified polymer is obtained by a chain extension reaction of a hydroxyl-terminated silicone oil with boric acid and / or diboric acid, and then terminated with an isocyanate acrylate; Or, the modified polymer is obtained by a chain extension reaction of boric acid or diboric acid with a hydroxyl-terminated acrylate polymer, and then terminated with 2-hydroxyethyl acrylate.

6. The adhesive composition according to claim 5, characterized in that, The structural formula of the modified polymer is Formula (3), and the structure of Formula (3) is shown as follows: Wherein, R1 in Formula (3) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (3) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; Or, the structural formula of the modified polymer is Formula (4), and the structure of Formula (4) is shown as follows: Wherein, R1 in Formula (4) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (4) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; Or, the structural formula of the modified polymer is Formula (5), and the structure of Formula (5) is shown as follows: Wherein, R1 in Formula (5) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group, and n is an integer greater than or equal to 1; Or, the structural formula of the modified polymer is Formula (6), and the structure of Formula (6) is shown as follows: Wherein, R1 in Formula (6) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group, and n is an integer greater than or equal to 1.

7. An adhesive composition, characterized in that, Including: An adhesive matrix, and the adhesive matrix includes a silicone resin; A modified polymer, wherein a boron-oxygen coordination and / or a boron-oxygen coordination bond is included in the main chain of the modified polymer, vinyl groups are included in the end groups and / or side chains of the modified polymer, and the modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with boric acid or diboric acid through a chain extension reaction and then end-capping with a vinyl silicone oil.

8. The adhesive composition according to claim 7, characterized in that, The silicone resin includes a polydiorganosiloxane, active hydrogen atoms are included in the end groups and / or side groups of the polydiorganosiloxane, and each organic group in the polydiorganosiloxane includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group.

9. A method for preparing an adhesive composition, characterized in that, Including: Mixing the adhesive matrix with the modified polymer to obtain the adhesive composition, wherein a boron-oxygen coordination and / or a boron-oxygen coordination bond is included in the main chain of the modified polymer, hydroxyl groups are included in the end groups and / or side chains of the modified polymer, and the adhesive matrix includes at least one of a silicone resin and an epoxy resin.

10. The preparation method according to claim 9, characterized in that, The modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with boric acid and / or diboric acid.

11. The preparation method according to claim 9, characterized in that, The modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with boric acid, and the structural formula of the modified polymer is Formula (1), and the structure of Formula (1) is shown as follows: Wherein, R1 in Formula (1) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (1) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; Or, the modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with diboric acid, and the structural formula of the modified polymer is Formula (2), and the structure of Formula (2) is shown as follows: Wherein, R1 in Formula (2) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (2) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group.

12. The preparation method according to claim 10 or 11, characterized in that, The hydroxyl-terminated silicone oil includes hydroxyl-terminated silicone oils with three molecular weights, and the viscosities of the hydroxyl-terminated silicone oils with the three molecular weights are respectively greater than or equal to 15000 cps, 4000 - 15000 cps, and less than or equal to 4000 cps.

13. The preparation method according to claim 12, wherein The mass fraction ratio of the hydroxyl-terminated silicone oils with viscosities respectively greater than or equal to 15000 cps, 4000 - 15000 cps, and less than or equal to 4000 cps is (30 - 60):(20 - 50):(20 - 30); The total mass fraction of the boric acid and / or diboric acid is 0.1 - 5.

14. The preparation method according to claim 10, characterized in that, The silicone resin includes a polydiorganosiloxane end-capped with at least one of an alkoxy group, an acyloxy group, and a ketoxime group, and each organic group in the polydiorganosiloxane includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; The epoxy resin includes at least one of bisphenol A epoxy resin and bisphenol F epoxy resin.

15. A method for preparing an adhesive composition, characterized in that, Comprising: The adhesive composition is obtained by mixing an adhesive matrix with a modified polymer, wherein the adhesive matrix includes acrylate monomers, the main chain of the modified polymer contains boron-oxygen coordination and / or boron-oxygen coordination bonds, the end groups and / or side chains of the modified polymer contain acrylate groups, and the modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with boric acid and / or diboric acid to obtain an intermediate, and then reacting the intermediate with isocyanate acrylate.

16. The preparation method according to claim 15, characterized in that, The modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with boric acid to obtain an intermediate, and then reacting the intermediate with isocyanate acrylate. Wherein, the structural formula of the modified polymer is Formula (3), and the structure of Formula (3) is shown as follows: Wherein, R1 in Formula (3) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (3) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group. Or, the modified polymer is obtained by reacting a hydroxyl-terminated silicone oil with diboric acid to obtain an intermediate; and then reacting the intermediate with isocyanate acrylate to obtain the modified polymer. Wherein, the structural formula of the modified polymer is Formula (4), and the structure of Formula (4) is shown as follows: Wherein, R1 in Formula (4) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group; R2 in Formula (4) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group.

17. A method for preparing an adhesive composition, characterized in that, Comprising: The adhesive composition is obtained by mixing an adhesive matrix with a modified polymer, wherein the adhesive matrix includes acrylate monomers, the main chain of the modified polymer contains boron-oxygen coordination and / or boron-oxygen coordination bonds, the end groups and / or side chains of the modified polymer contain acrylate groups, and the modified polymer is obtained by reacting a hydroxyl-terminated acrylate polymer with boric acid and / or diboric acid to generate an intermediate, and then reacting the intermediate with a hydroxyacrylate monomer.

18. The preparation method according to claim 17, characterized in that, The modified polymer is obtained by reacting a hydroxyl-terminated acrylate polymer with boric acid to generate an intermediate, and then reacting the intermediate with a hydroxyacrylate monomer. Wherein, the structural formula of the modified polymer is Formula (5), and the structure of Formula (5) is shown as follows: Wherein, R1 in Formula (5) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group, and n is an integer greater than or equal to 1. Or, the modified polymer is obtained by reacting a hydroxyl-terminated acrylate polymer with diboric acid to generate an intermediate; and then reacting the intermediate with a hydroxyacrylate monomer. Wherein, the structural formula of the modified polymer is Formula (6), and the structure of Formula (6) is shown as follows: Wherein, R1 in Formula (6) includes any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group, and n is an integer greater than or equal to 1.

19. A method for preparing an adhesive composition, characterized in that, Comprising: The adhesive composition is obtained by mixing an adhesive matrix with a modified polymer, wherein the adhesive matrix comprises a silicone resin, the main chain of the modified polymer contains boron-oxygen coordination and / or boron-oxygen linkage bonds, the end groups and / or side chains of the modified polymer contain vinyl groups, and the modified polymer is obtained by reacting a hydroxy-terminated acrylate polymer with boric acid and / or diboric acid to form an intermediate, and then reacting the intermediate with vinyl silicone oil.

20. The preparation method according to claim 19, characterized in that, The silicone resin comprises polydiorganosiloxane, the end groups and / or side groups of the polydiorganosiloxane contain active hydrogen atoms, and each organic group in the polydiorganosiloxane comprises any one of an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, and an aryl group.

21. An optical adhesive film, characterized in that, Cured from the adhesive composition according to any one of claims 1 to 8, the molecular chain of the optical adhesive film contains boron-oxygen coordination and / or boron-oxygen linkage bonds.

22. A foldable screen, characterized in that, Comprising a panel, and at least one substrate layer and at least one optical adhesive film stacked on the surface of the panel, wherein one layer of the optical adhesive film is provided between the panel and the adjacent substrate layer, and between two adjacent substrate layers, and the optical adhesive film is the optical adhesive film according to claim 21.

23. An electronic device, characterized in that, Comprising the optical adhesive film according to claim 21, or the folding screen according to claim 22.

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