Silicone encapsulation adhesive for micro LED components and encapsulation method and application thereof

Abstract

The present invention discloses an organic silicon encapsulant for micro LED components. By using a branched alkenyl-containing polysiloxane with an alkenyl group, a photopolymerizable group and an aromatic group, a straight-chain hydrogen-containing polysiloxane with an aromatic group and a straight-chain organic polysiloxane with an aromatic group and a photopolymerizable group as a matrix resin, and using them in combination with a photopolymerization initiator and a hydrosilylation catalyst that does not show catalytic activity when irradiated with ultraviolet rays, the organic silicon encapsulant of the present invention has suitable viscosity and good staged curing characteristics, that is, it can be photocured first to form a photocured encapsulation layer, and then thermally cured to form a thermally cured encapsulation layer; and the thermally cured encapsulation layer has a flat surface, uniform thickness, moderate hardness, and good light transmittance, light and heat aging resistance and mechanical properties. The present invention also discloses a packaging method for a micro LED component, a packaged micro LED component and an optical display device.

Description

Technical Field

[0001] The present invention relates to an organic silicone encapsulant, in particular to an organic silicone encapsulant for micro LED elements, and also to a method for encapsulating micro LED elements using the organic silicone encapsulant, encapsulated micro LED elements obtained using the encapsulation method, and an optical display device comprising the micro LED elements. Background Art

[0002] Micro LEDs such as mini LED or micro LED have many advantages such as high brightness, high contrast, high definition, strong reliability, fast response time, more energy saving, lower power consumption, etc., and have now become an important development direction of the new generation of LED display technology.

[0003] The packaging process is the key to determining the yield and process efficiency of micro LED products. Since the packaging process of micro LED is relatively complex, it usually needs to be processed in stages. In order to meet this process requirement, the packaging glue used for micro LED often needs to have the characteristics of staged curing, such as first curing to form a semi-cured material that can maintain a certain shape, and then after subsequent processing, a secondary curing is performed to obtain a fully cured solid. In addition, the packaging glue used for micro LEDs also needs to have good light transmittance and light and heat aging resistance.

[0004] However, there is currently no packaging adhesive for micro LEDs that fully matches the above-mentioned packaging process requirements. Summary of the invention

[0005] One of the purposes of the present invention is to provide a silicone encapsulant for micro LED components, which has suitable viscosity and good staged curing characteristics, that is, it can be photocured first to form a photocured encapsulation layer, and then thermally cured to form a thermally cured encapsulation layer; and the thermally cured encapsulation layer has a smooth surface, uniform thickness, moderate hardness, and also has good light transmittance, light and heat aging resistance and mechanical properties.

[0006] A second object of the present invention is to provide a packaging method for a micro LED element using the aforementioned organic silicon packaging adhesive.

[0007] A third object of the present invention is to provide a packaged product of a micro LED element obtained by implementing the aforementioned packaging method.

[0008] A fourth object of the present invention is to provide an optical display device comprising the aforementioned packaged product.

[0009] In one aspect, the present invention provides a silicone encapsulant for a micro LED device, comprising:

[0010] (A) 100 parts by weight of a branched alkenyl-containing polysiloxane having a structure represented by formula (1):

[0011] (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (1)

[0012] In formula (1), a, b, c, and d represent molar ratios, and 0<a<1, 0≤b<1, 0≤c<1, 0≤d<0.6, a+b+c+d=1, and c+d>0; each R1 independently represents an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a photopolymerizable group, and in all R 1 The molar percentage content of alkenyl in the total R 1 The molar percentage content of aromatic groups in the 1 The molar percentage content of the photopolymerizable groups is 0.5 mol % to 20 mol %;

[0013] (B) 5 to 50 parts by weight of a linear hydrogen-containing polysiloxane having a structure represented by formula (2):

[0014] (R 2 3SiO 1 / 2 )(R 2 2SiO 2 / 2 ) m (R 2 3SiO 1 / 2 ) (2)

[0015] In formula (2), m represents the degree of polymerization, and m is an integer from 1 to 20; each R 2 independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms, wherein at least two R 2 is a hydrogen atom, and in all R 2 The molar percentage content of aromatic groups is 10 mol % to 70 mol %;

[0016] (C) 1 to 30 parts by weight of a linear organopolysiloxane having a structure represented by formula (3):

[0017] (R 3 3SiO 1 / 2 )(R3 2SiO 2 / 2 ) n (R 3 3SiO 1 / 2 ) (3)

[0018] In formula (3), n represents the degree of polymerization, and n is an integer from 1 to 50; each R 3 independently represent an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a photopolymerizable group, wherein at least two R 3 is a photopolymerizable group, and in all R 3 The molar percentage content of aromatic groups is 10 mol % to 70 mol %;

[0019] (D) 0.01 to 5 parts by weight of a photopolymerization initiator;

[0020] (E) 0.001 to 5 parts by weight of a hydrosilylation catalyst which does not show catalytic activity when irradiated with ultraviolet rays.

[0021] According to the organic silicon encapsulant of the present invention, preferably, in formula (1) and formula (3), the photopolymerizable group has a structure shown in formula (A):

[0022] CH2=CHR a -R b -R c - (A)

[0023] In formula (A), R a Represents a hydrogen atom or a methyl group; R b Indicates -R b1 -O-, -C(=O)O- or -C(=O)-NR b2 R b3 -, where R b1 represents a single bond or an alkylene group having 1 to 4 carbon atoms, R b2 , R b3 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and R c It represents an alkylene group having 1 to 4 carbon atoms or an arylene group having 6 to 12 carbon atoms.

[0024] The organic silicon encapsulant according to the present invention preferably further comprises: (F) a hydrosilylation inhibitor or (G) an adhesion promoter.

[0025] According to the organic silicon encapsulant of the present invention, preferably, the dynamic viscosity of the organic silicon encapsulant at 25° C. is 500 mPa∙s to 10000 mPa∙s.

[0026] In another aspect, the present invention further provides a method for packaging a micro LED element, comprising:

[0027] (S1) coating step: coating any of the aforementioned silicone encapsulants on the surface of the micro LED element to form an uncured encapsulation layer;

[0028] (S2) a photocuring step: photocuring the uncured encapsulation layer to form a photocured encapsulation layer;

[0029] (S3) Thermal curing step: thermally curing the photocured encapsulation layer to form a thermally cured encapsulation layer.

[0030] According to the packaging method of the present invention, preferably, the micro LED element is a micro LED element or a minLED element.

[0031] According to the packaging method of the present invention, preferably, the photocuring is performed under ultraviolet light irradiation with a wavelength of 250nm to 380nm.

[0032] According to the encapsulation method of the present invention, preferably, the thermal curing is performed at a temperature of 50°C to 200°C.

[0033] In another aspect, the present invention further provides a packaged micro LED component, which is obtained by packaging the micro LED component using the packaging method as described above.

[0034] In yet another aspect, the present invention further provides an optical display device, comprising the aforementioned packaged micro-LED element.

[0035] The present invention unexpectedly found that by using a branched alkenyl-containing polysiloxane with alkenyl, photopolymerizable groups and aromatic groups, a linear hydrogen-containing polysiloxane with aromatic groups and a linear organopolysiloxane with aromatic groups and photopolymerizable groups as a matrix resin, and using them in combination with a photopolymerization initiator and a hydrosilylation catalyst that does not show catalytic activity when irradiated with ultraviolet rays, the organic silicon encapsulant prepared thereby has suitable viscosity and good staged curing characteristics, that is, it can be photocured first to form a photocured encapsulation layer, and then thermally cured to form a thermally cured encapsulation layer; and the thermally cured encapsulation layer has a flat surface, uniform thickness, moderate hardness, and also has good light transmittance, light and heat aging resistance and mechanical properties. Thus, micro LED components and optical display devices with good encapsulation performance can be prepared. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited thereto.

[0037] <Term Explanation>

[0038] In the present invention, the “micro LED component” mentioned refers to an LED component with an LED chip size of less than 500 microns; the “mini LED component” mentioned refers to a micro LED component with an LED chip size of 50 to 150 microns; the “micro LED component” mentioned refers to a micro LED component with an LED chip size of less than 50 microns.

[0039] <Silicone encapsulant for micro LED components>

[0040] The present invention provides an organic silicon encapsulant for a micro LED element, comprising:

[0041] (A) 100 parts by weight of a branched alkenyl-containing polysiloxane having a structure represented by formula (1):

[0042] (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (1)

[0043] In formula (1), a, b, c, and d represent molar ratios, and 0<a<1, 0≤b<1, 0≤c<1, 0≤d<0.6, a+b+c+d=1 and c+d>0; each R 1 independently represent an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a photopolymerizable group, and in all R 1 The molar percentage content of alkenyl in the total R 1 The molar percentage content of aromatic groups in the 1 The molar percentage content of the photopolymerizable groups is 0.5 mol % to 20 mol %;

[0044] (B) 10 to 60 parts by weight of a linear alkenyl-containing polysiloxane having a structure represented by formula (2):

[0045] (R 2 3SiO 1 / 2 )(R 2 2SiO 2 / 2 ) m (R 2 3SiO 1 / 2 ) (2)

[0046] In formula (2), m represents the degree of polymerization, and m is an integer from 1 to 20; each R 2 independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms, wherein at least two R 2 is a hydrogen atom, and in all R 2 The molar percentage content of aromatic groups is 10 mol % to 70 mol %;

[0047] (C) 10 to 50 parts by weight of a linear hydrogen-containing polysiloxane having a structure represented by formula (3):

[0048] (HR 3 2SiO 1 / 2 )(R 3 2SiO 2 / 2 ) n (R 3 3SiO 1 / 2 ) (3)

[0049] In formula (3), n represents the degree of polymerization, and n is an integer from 1 to 50; each R 3 independently represent an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a photopolymerizable group, wherein at least two R 3 is a photopolymerizable group, and in all R 3 The molar percentage content of aromatic groups is 10 mol % to 70 mol %;

[0050] (D) 0.01 to 5 parts by weight of a photopolymerization initiator;

[0051] (E) 0.001 to 5 parts by weight of a hydrosilylation catalyst which does not show catalytic activity when irradiated with ultraviolet rays.

[0052] In the present invention, the organic silicone encapsulant may optionally further include: (F) a hydrosilylation inhibitor or (G) an adhesion promoter.

[0053] In the present invention, the dynamic viscosity of the organic silicone encapsulant at 25° C. is generally 500 mPa∙s to 10000 mPa∙s, preferably 800 mPa∙s to 8000 mPa∙s, and more preferably 1000 Pa∙s to 5000 mPa∙s.

[0054] The present invention finds that by using a branched alkenyl-containing polysiloxane with an alkenyl group, a photopolymerizable group and an aromatic group, a straight-chain hydrogen-containing polysiloxane with an aromatic group and a straight-chain organopolysiloxane with an aromatic group and a photopolymerizable group as a base resin, and using them in combination with a photopolymerization initiator and a hydrosilylation catalyst that does not show catalytic activity when irradiated with ultraviolet rays, the organic silicon encapsulant prepared thereby has suitable viscosity and good staged curing characteristics, that is, it can be photocured first to form a photocured encapsulation layer, and then thermally cured to form a thermally cured encapsulation layer; and the thermally cured encapsulation layer has a flat surface, uniform thickness, moderate hardness, and also has good light transmittance, light and heat aging resistance and mechanical properties. Thus, micro LED components and optical display devices with good encapsulation performance can be prepared.

[0055] Branched alkenyl-containing polysiloxane (A)

[0056] The organic silicon encapsulant of the present invention comprises a branched alkenyl-containing polysiloxane (A) having a structure shown in formula (1):

[0057] (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (1)

[0058] In formula (1), a, b, c, and d represent molar ratios, and 0<a<1, 0≤b<1, 0<c<1, 0≤d≤0.3, a+b+c+d=1, and c+d>0; each R 1 independently represent an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a photopolymerizable group, and in all R 1 The molar percentage content of alkenyl in the total R 1 The molar percentage content of aromatic groups in the 1 The molar percentage content of the photopolymerizable groups is 0.5 mol % to 20 mol %.

[0059] In formula (1), preferably, 0.05<a<0.5, 0≤b<0.4, 0.1≤c<0.9, 0≤d<0.6, a+b+c+d=1 and c+d>0. More preferably, 0.1<a<0.4, 0≤b<0.3, 0.2≤c<0.85, 0≤d<0.5, a+b+c+d=1 and c+d>0.

[0060] In formula (1), the alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group or an isobutyl group, more preferably a methyl group or an ethyl group, and most preferably a methyl group.

[0061] In formula (1), the aryl group is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group.

[0062] In formula (1), the alkenyl group is preferably vinyl, propenyl, butenyl or hexenyl, more preferably vinyl or allyl, and most preferably vinyl.

[0063] In formula (1), the photopolymerizable group preferably has a structure represented by formula (A):

[0064] CH2=CHR a -R b -R c - (A)

[0065] In formula (A), R a Represents a hydrogen atom or a methyl group; R b Indicates -R b1 -O-, -C(=O)O- or -C(=O)-NRb2Rb3-, wherein Rb1 represents a single bond or an alkylene group having 1 to 4 carbon atoms, preferably a single bond, methylene, ethylene or propylene, more preferably a single bond, methylene or ethylene; R b2 , R b3 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom, a methyl group, an ethyl group, a n-propyl group or an isopropyl group, more preferably a hydrogen atom, a methyl group or an ethyl group; and R c It represents an alkylene group having 1 to 4 carbon atoms, preferably a methylene group, an ethylene group or a propylene group, more preferably an ethylene group or a propylene group, most preferably a propylene group, or an arylene group having 6 to 12 carbon atoms, preferably a phenylene group or a naphthylene group, more preferably a phenylene group.

[0066] More preferably, the photopolymerizable group is an acryloyloxypropyl group or a methacryloyloxypropyl group.

[0067] In formula (1), in all R 1 The molar percentage content of the alkenyl group is 1 mol % to 30 mol %, preferably 2 mol % to 20 mol %, and more preferably 5 mol % to 15 mol %.

[0068] In formula (1), in all R 1 The molar percentage content of the aromatic group is 10 mol % to 70 mol %, preferably 20 mol % to 60 mol %, and more preferably 35 mol % to 55 mol %.

[0069] In formula (1), in all R1 The molar percentage content of the photopolymerizable groups is 0.5 mol % to 20 mol %, preferably 1 mol % to 15 mol %, and more preferably 2 mol % to 10 mol %.

[0070] In the present invention, the branched alkenyl-containing polysiloxane (A) preferably has a structure represented by formula (1-1), formula (1-2) or formula (1-3):

[0071] (ViMe2SiO 1 / 2 ) 0.15 (Me3SiO 1 / 2 ) 0.10 (APSiO 3 / 2 ) 0.05 (PhSiO 3 / 2 ) 0.70 (1-1)

[0072] In formula (1-1), Vi represents a vinyl group, Me represents a methyl group, AP represents an acryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to the silicon atom, the molar percentage content of the vinyl group is 10 mole %, the molar percentage content of the phenyl group is 46.7 mole %, and the molar percentage content of the acryloxypropyl group is 3.3 mole %.

[0073] (ViMe2SiO 1 / 2 ) 0.13 (Me3SiO 1 / 2 ) 0.1 (MePhSiO 2 / 2 ) 0.03 (MAPSiO 3 / 2 ) 0.06 (PhSiO 3 / 2 ) 0.68 (1-2)

[0074] In formula (1-2), Vi represents a vinyl group, Me represents a methyl group, MAP represents a methacryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to silicon atoms, the molar percentage content of the vinyl group is 8.7 mole %, the molar percentage content of the phenyl group is 47.7 mole %, and the molar percentage content of the methacryloxypropyl group is 4.0 mole %.

[0075] (ViMe2SiO 1 / 2 ) 0.10 (Me3SiO 1 / 2 ) 0.12 (Me2SiO 2 / 2 ) 0.082 (APSiO 3 / 2 ) 0.03 (PhSiO 3 / 2 )0.618 (SiO 4 / 2 ) 0.05 (1-3)

[0076] In formula (1-3), Vi represents a vinyl group, Me represents a methyl group, AP represents an acryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to the silicon atom, the molar percentage content of the vinyl group is 6.6 mole %, the molar percentage content of the phenyl group is 40.7 mole %, and the molar percentage content of the acryloxypropyl group is 2.0 mole %.

[0077] Linear hydrogen-containing polysiloxane (B)

[0078] The organic silicon encapsulant of the present invention further comprises a linear hydrogen-containing polysiloxane (B) having a structure shown in formula (2):

[0079] (R 2 3SiO 1 / 2 )(R 2 2SiO 2 / 2 ) m (R 2 3SiO 1 / 2 ) (2)

[0080] In formula (2), m represents the degree of polymerization, and m is an integer from 1 to 20; each R 2 independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and at least two R 2 is a hydrogen atom, and in all R 2 The molar percentage of the aromatic group is 10 mol % to 70 mol %.

[0081] In formula (2), m is preferably an integer of 1 to 10, and more preferably an integer of 1 to 5.

[0082] In formula (2), the alkyl group is preferably a methyl group, an ethyl group, a n-propyl group or an isopropyl group, more preferably a methyl group or an ethyl group, and most preferably a methyl group.

[0083] In formula (2), the aryl group is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group.

[0084] In formula (2), at least two R 2 is a hydrogen atom, preferably 2 to 4 R 2 is a hydrogen atom, more preferably two R 2 A hydrogen atom.

[0085] In formula (2), in all R 2 The molar percentage content of the aromatic group is 10 mol % to 70 mol %, preferably 15 mol % to 60 mol %, and more preferably 20 mol % to 55 mol %.

[0086] In the present invention, the linear hydrogen-containing polysiloxane (B) preferably has a structure represented by formula (2-1), formula (2-2) or formula (2-3):

[0087] (HMe2SiO 1 / 2 )(Ph2SiO 2 / 2 )2(HMe2SiO 1 / 2 ) (2-1)

[0088] In formula (2-1), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 40 mol %.

[0089] (HMe2SiO 1 / 2 )(Ph2SiO 2 / 2 )(HMe2SiO 1 / 2 ) (2-2)

[0090] In formula (2-2), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 25 mol %.

[0091] (HPh2SiO 1 / 2 )(Me2SiO 2 / 2 )(HPh2SiO 1 / 2 ) (2-3)

[0092] In formula (2-3), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 50 mol %.

[0093] In the present invention, the amount of the hydrogen-containing polysiloxane (B) is 5 to 50 parts by weight, preferably 10 to 45 parts by weight, and more preferably 20 to 40 parts by weight, relative to 100 parts by weight of the branched alkenyl-containing polysiloxane (A).

[0094] Straight chain organopolysiloxane (C)

[0095] The organic silicon encapsulant of the present invention further comprises a linear organic polysiloxane (C) having a structure shown in formula (3):

[0096] (R 3 3SiO 1 / 2 )(R 3 2SiO 2 / 2 ) n (R 3 3SiO 1 / 2 ) (3)

[0097] In formula (3), n represents the degree of polymerization, and n is an integer from 1 to 50; each R 3 independently represent an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a photopolymerizable group, wherein at least two R 3 is a photopolymerizable group, and in all R 3 The molar percentage of the aromatic group is 10 mol % to 70 mol %.

[0098] In formula (3), n is preferably an integer of 2 to 40, and more preferably an integer of 5 to 30.

[0099] In formula (3), the alkyl group is preferably a methyl group, an ethyl group, a n-propyl group or an isopropyl group, more preferably a methyl group or an ethyl group, and most preferably a methyl group.

[0100] In formula (3), the aryl group is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group.

[0101] In formula (3), the photopolymerizable group preferably has a structure represented by formula (A):

[0102] CH2=CHR a -R b -R c - (A)

[0103] In formula (A), R a Represents a hydrogen atom or a methyl group; R b Indicates -R b1 -O-, -C(=O)O- or -C(=O)-NR b2 R b3 -, where R b1 represents a single bond or an alkylene group having 1 to 4 carbon atoms, preferably a single bond, a methylene group, an ethylene group or a propylene group, more preferably a single bond, a methylene group or an ethylene group; R b2 , R b3 Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom, a methyl group, an ethyl group, a n-propyl group or an isopropyl group, more preferably a hydrogen atom, a methyl group or an ethyl group; and R c It represents an alkylene group having 1 to 4 carbon atoms, preferably a methylene group, an ethylene group or a propylene group, more preferably an ethylene group or a propylene group, most preferably a propylene group, or an arylene group having 6 to 12 carbon atoms, preferably a phenylene group or a naphthylene group, more preferably a phenylene group.

[0104] More preferably, the photopolymerizable group is an acryloyloxypropyl group or a methacryloyloxypropyl group.

[0105] In formula (3), at least two R 3 is a photopolymerizable group, preferably 2 to 4 R3 are photopolymerizable groups, and more preferably two R3 are photopolymerizable groups.

[0106] In formula (3), in all R 3 The molar percentage content of the aromatic group is 10 mol % to 70 mol %, preferably 20 mol % to 60 mol %, and more preferably 35 mol % to 55 mol %.

[0107] In the present invention, the linear organopolysiloxane (C) preferably has a structure represented by formula (3-1), formula (3-2) or formula (3-3):

[0108] (APMe2SiO 1 / 2 )(MePhSiO 2 / 2 ) 20 (APMe2SiO 1 / 2 ) (3-1)

[0109] In formula (3-1), Me represents a methyl group, Ph represents a phenyl group, AP represents an acryloxypropyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 43.5 mol %.

[0110] (MAPMe2SiO 1 / 2 )(MePhSiO 2 / 2 ) 25 (MAPMe2SiO 1 / 2 ) (3-2)

[0111] In formula (3-2), Me represents a methyl group, Ph represents a phenyl group, MAP represents a methacryloxypropyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 44.6 mol %.

[0112] (APMe2SiO 1 / 2 )(Ph2SiO 2 / 2 ) 10 (Me2SiO 2 / 2 )6(APMe2SiO 1 / 2 ) (3-3)

[0113] In formula (3-3), Me represents a methyl group, Ph represents a phenyl group, AP represents an acryloxypropyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 52.6 mol %.

[0114] In the present invention, the amount of the linear organopolysiloxane (C) is 1 to 30 parts by weight, preferably 5 to 25 parts by weight, and more preferably 10 to 20 parts by weight, relative to 100 parts by weight of the branched alkenyl-containing polysiloxane (A).

[0115] Photopolymerization initiator (D)

[0116] The organic silicon encapsulant of the present invention further comprises a photopolymerization initiator (D).

[0117] In the present invention, the type of the photopolymerization initiator (D) is not particularly limited, including but not limited to: α-hydroxy aromatic ketones, such as 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 1-hydroxy-cyclohexyl benzophenone (184), etc.; acylphosphorus oxides, such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2,4,6-trimethylbenzoylphosphonic acid ethyl ester (TPO-L), etc.; benzophenones, such as benzophenone, tetramethyl Michler's ketone, tetraethyl Michler's ketone, methyl ethyl Michler's ketone, etc.; benzoin, such as benzoin dimethyl ether (BDK or 651); benzil; anthraquinone, such as 2-isopropylthioxanthone (ITX), etc. Preferably, the photopolymerization initiator (D) is α-hydroxy aromatic ketone or acylphosphorus oxide. More preferably, the photopolymerization initiator (D) is 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 1-hydroxy-cyclohexyl benzophenone (184) or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO). Most preferably, the photopolymerization initiator (D) is 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173).

[0118] In the present invention, the content of the radical photopolymerization initiator (D) is 0.01 to 5 parts by weight, preferably 0.05 to 4 parts by weight, and more preferably 0.1 to 2 parts by weight, relative to 100 parts by weight of the branched alkenyl-containing polysiloxane (A).

[0119] Hydrosilylation catalyst (E)

[0120] The organic silicon encapsulant of the present invention further comprises a hydrosilylation catalyst (E), which does not show catalytic activity when irradiated with ultraviolet rays.

[0121] In the present invention, the hydrosilylation catalyst (E) is preferably a platinum-containing compound, such as chloroplatinic acid, a reaction product of chloroplatinic acid and an alcohol, a platinum-olefin complex, a platinum-vinylsilane complex, a platinum-ketone complex, a platinum-phosphine complex; a rhodium-containing compound, such as a rhodium-phosphine complex, a rhodium-sulfur compound complex; a palladium-containing compound, such as a palladium-phosphine complex. More preferably, the hydrosilylation catalyst (E) is a complex of platinum and vinylsiloxane, such as a Custer catalyst.

[0122] In the present invention, the amount of the hydrosilylation catalyst (E) is 0.001 to 5 parts by weight, preferably 0.005 to 3 parts by weight, and more preferably 0.01 to 1 part by weight, relative to 100 parts by weight of the branched alkenyl-containing polysiloxane (A).

[0123] Hydrosilylation inhibitor (F)

[0124] Optionally, the organic silicon encapsulant of the present invention may further comprise: a hydrosilylation inhibitor (F).

[0125] In the present invention, the type of the hydrosilylation inhibitor (F) is not particularly limited, and types known in the art can be used. Examples of the hydrosilylation inhibitor (F) include, but are not limited to: one or a combination of two or more of phosphorus-containing compounds, nitrogen-containing compounds, maleic acid derivatives, alkynols, and vinyl silanes. The phosphorus-containing compound is preferably triphenylphosphine. The nitrogen-containing compound is preferably one or a combination of two or more of tributylamine, tetramethylethylenediamine, and benzotriazole. The maleic acid derivative is preferably dimethyl maleate. The alkynol is preferably one or a combination of two or more of 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, and 3-methylbutynol. The vinyl silane is preferably 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane. Preferably, the hydrosilylation inhibitor (F) is an alkynol. More preferably, the hydrosilylation inhibitor (F) is one or a combination of two or more of 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, and 3-methylbutynol.

[0126] In the present invention, the amount of the hydrosilylation inhibitor (F) is 0.001 to 2 parts by weight, preferably 0.01 to 1.5 parts by weight, and more preferably 0.05 to 1 part by weight, relative to 100 parts by weight of the branched alkenyl-containing polysiloxane (A).

[0127] Adhesion promoter (G)

[0128] Optionally, the organic silicone encapsulant of the present invention may further comprise: an adhesion promoter (G).

[0129] In the present invention, the type of the adhesion promoter (G) is not particularly limited, and types known in the art can be used. Examples of the adhesion promoter (G) include, but are not limited to, one or a combination of two or more of vinyl trimethoxysilane, vinyl triethoxysilane, 3-(2,3-epoxypropoxy)propyl trimethoxysilane, 3-(2,3-epoxypropoxy)propyl triethoxysilane, acryloxypropyl trimethoxysilane, acryloxypropyl triethoxysilane, methacryloxypropyl trimethoxysilane, methacryloxypropyl triethoxysilane, mercaptopropyl trimethoxysilane, mercaptopropyl triethoxysilane, isocyanate propyl trimethoxysilane, and isocyanate propyl triethoxysilane. Preferably, the adhesion promoter (G) is one or a combination of two or more of vinyl trimethoxy silane, vinyl triethoxy silane, acryloxypropyl trimethoxy silane, acryloxypropyl triethoxy silane, methacryloxypropyl trimethoxy silane and methacryloxypropyl triethoxy silane.

[0130] In the present invention, the amount of the adhesion promoter (G) is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and more preferably 1 to 3 parts by weight, relative to 100 parts by weight of the branched alkenyl-containing polysiloxane (A).

[0131] <Micro LED component packaging method>

[0132] The present invention also provides a method for packaging a micro LED element, comprising:

[0133] (S1) coating step: coating the organic silicon encapsulation adhesive of the present invention on the surface of the micro LED element to form an uncured encapsulation layer;

[0134] (S2) a photocuring step: photocuring the uncured encapsulation layer to form a photocured encapsulation layer;

[0135] (S3) Thermal curing step: thermally curing the photocured encapsulation layer to form a thermally cured encapsulation layer.

[0136] In the coating step (S1), the LED chip size of the micro LED element is not particularly limited, and is generally less than 500 microns, preferably less than 200 microns, and more preferably less than 150 microns. Preferably, the micro LED element is a mini LED element or a micro LED element. The coating method is not particularly limited, and can be dispensing, scraping, spraying, slit coating or screen printing.

[0137] In the light curing step (S2), the light curing is performed under ultraviolet light with a wavelength of 250nm to 400nm, preferably 365nm or 395nm. The ultraviolet light intensity is preferably 1 mW / cm 2 Up to 200mW / cm 2 , more preferably 10 mW / cm 2 Up to 100mW / cm 2 The ultraviolet light irradiation time is preferably less than 100 seconds, more preferably less than 60 seconds. The light-cured encapsulation layer is usually in a non-flowing gel state at room temperature and normal pressure.

[0138] In the thermal curing step (S3), the thermal curing is performed at a temperature of 50°C to 200°C, preferably 100°C to 180°C. The thermal curing time is preferably 30 minutes to 5 hours, more preferably 1 hour to 3 hours. The thermally cured encapsulation layer usually has a smooth surface, that is, without orange peel or pitting defects.

[0139] In the present invention, the heat-cured encapsulation layer generally has one or more of the following properties:

[0140] (1) Good thickness uniformity, that is, the thickness error is within ±8%;

[0141] (2) Suitable hardness, i.e., hardness of Shore D20 to Shore D65;

[0142] (3) Good light transmittance, that is, the transmittance at 450nm is more than 95%;

[0143] (4) Good resistance to light and heat aging, that is, the light transmittance maintenance rate at 450nm at 150℃*1000 hours is more than 99%, and the light transmittance maintenance rate at 450nm at 150℃*1000 hours is more than 90%;

[0144] (5) Good mechanical properties, i.e., according to the test of standard GB / T 1701-2001, the tensile strength is above 3.0 MPa and the elongation at break is above 50%.

[0145] <Packaged micro LED components>

[0146] The present invention further provides a packaged micro LED element, which is obtained by packaging the micro LED element using the packaging method of the present invention.

[0147] In the present invention, the LED chip size of the micro LED element is not particularly limited, and is generally less than 500 microns, preferably less than 200 microns, and more preferably less than 150 microns. Preferably, the micro LED element is a mini LED element or a micro LED element.

[0148] In a specific embodiment of the present invention, the packaged micro LED element is obtained by packaging a mini LED element or a micro LED element using the packaging method of the present invention.

[0149] <Optical Display Device>

[0150] The present invention further provides an optical display device, which comprises the packaged micro-LED element of the present invention.

[0151] In the present invention, the type of the optical display device is not particularly limited, including but not limited to a liquid crystal display (LCD), a thin film transistor liquid crystal display (TFT-LCD), and the like.

[0152] In a specific embodiment of the present invention, the optical display device comprises a backlight module, wherein the backlight module comprises the packaged micro LED element described in the present invention.

[0153] Example

[0154] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited by these specific embodiments.

[0155] <Test Method>

[0156] Viscosity: According to the determination method specified in standard GB / T 2794-2013, the dynamic viscosity of the silicone encapsulant at 25°C was measured using a DV-II rotational viscometer.

[0157] Hardness: The silicone encapsulant is placed under an LED UV lamp with a working wavelength of 365nm at 50mW / cm 2 The hardness of the cured sheet was measured using an EHS5D digital display Shore hardness tester according to the test method specified in GB / T 2411-2008.

[0158] Tensile strength and elongation at break: The silicone encapsulant was exposed to an LED UV lamp with a working wavelength of 365 nm and a power of 50 mW / cm 2 The cured sheet was irradiated with an intensity of 1000 nm for 50 seconds and then thermally cured at 150°C for 2 hours to prepare a cured sheet with a thickness of 2 mm. According to the determination method specified in standard GB / T 1701-2001, the cured sheet was cut into tensile specimens of specified size, and the tensile strength and elongation at break of the tensile specimens were determined using an Instron 2367 universal material testing machine.

[0159] Light transmittance: The silicone encapsulant is exposed to a UV light with a wavelength of 365 nm at 50 mW / cm 2 The cured sheet was irradiated with an intensity of 50 seconds and then thermally cured at 150° C. for 2 hours to prepare a cured sheet with a thickness of 1 mm. The transmittance of the cured sheet at 450 nm was measured using a UV-3100PC scanning ultraviolet / visible spectrophotometer.

[0160] Transmittance maintenance rate: The silicone encapsulant is placed under an LED UV lamp with a working wavelength of 365nm at 50mW / cm 2 The cured sheet was irradiated with an intensity of 50 seconds, and then thermally cured at a temperature of 150°C for 2 hours to prepare a cured sheet with a thickness of 1 mm. The initial transmittance T0 of the cured sheet at 450 nm was measured using a UV-3100PC scanning UV / visible spectrophotometer, and then the cured sheet was placed in a 150°C oven and a standard xenon lamp aging box for continuous aging. After 1000 hours, the cured sheet was taken out and the transmittance T1000 at 450 nm was measured. The 150°C*1000 hour 450nm transmittance maintenance rate and the xenon lamp*1000 hour 450nm transmittance maintenance rate were calculated by the following formulas.

[0161] Transmittance maintenance rate = (T1000 / T0) × 100%

[0162] Cured film appearance evaluation: A 200*200mm PET release film was flatly adsorbed on the vacuum chuck of the automatic coating machine, and the silicone encapsulation glue was poured on the PET release film, and a 0.3mm thick film was automatically coated. The film was first exposed to an LED ultraviolet lamp with a working wavelength of 365nm at 50mW / cm 2 The film was irradiated with an intensity of 1000 nm for 50 seconds and then thermally cured at 150° C. for 2 hours to obtain a cured film. The cured film was visually observed for surface defects to evaluate its appearance.

[0163] Cured film thickness error: A PET release film with a size of 200*200mm is flatly adsorbed on the vacuum chuck of the automatic coating machine, and the silicone encapsulation glue is poured on the PET release film to automatically coat a film with a thickness of 0.3mm. The film is first irradiated with an intensity of 50mW / cm2 under an LED ultraviolet lamp with a working wavelength of 365nm for 50 seconds, and then thermally cured at a temperature of 150℃ for 2 hours to obtain a cured film. 20 points are evenly distributed on the cured film, and the thickness corresponding to these 20 points is measured respectively. The thickness error of the thermally cured film is calculated by the following formula.

[0164] Thickness error = ±0.5 × (maximum thickness - minimum thickness) / average thickness × 100%

[0165] <Example 1>

[0166] 100 parts by weight of a branched alkenyl-containing polysiloxane (A-1) as represented by formula (1-1), 35 parts by weight of a straight-chain hydrogen-containing polysiloxane (B-1) as represented by formula (2-1), 10 parts by weight of a straight-chain organopolysiloxane (C-1) as represented by formula (3-1), 1.5 parts by weight of a photopolymerization initiator 1173 (D), 0.08 parts by weight of a Custer catalyst having a platinum content of 0.5% (E), 0.1 parts by weight of 1-ethynylcyclohexanol (F), and 1.5 parts by weight of KH570 (G) are mixed evenly and vacuum degassed to obtain an organic silicone encapsulant.

[0167] (ViMe2SiO 1 / 2 ) 0.15 (Me3SiO 1 / 2 ) 0.10 (APSiO 3 / 2 ) 0.05 (PhSiO 3 / 2 ) 0.70 (1-1)

[0168] In formula (1-1), Vi represents a vinyl group, Me represents a methyl group, AP represents an acryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to the silicon atom, the molar percentage content of the vinyl group is 10 mole %, the molar percentage content of the phenyl group is 46.7 mole %, and the molar percentage content of the acryloxypropyl group is 3.3 mole %.

[0169] (HMe2SiO 1 / 2 )(Ph2SiO 2 / 2 )2(HMe2SiO 1 / 2 ) (2-1)

[0170] In formula (2-1), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 40 mol %.

[0171] (APMe2SiO 1 / 2 )(MePhSiO 2 / 2 ) 20 (APMe2SiO 1 / 2 ) (3-1)

[0172] In formula (3-1), Me represents a methyl group, Ph represents a phenyl group, AP represents an acryloxypropyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 43.5 mol %.

[0173] <Example 2>

[0174] 100 parts by weight of a branched alkenyl-containing polysiloxane (A-2) as represented by formula (1-2), 24 parts by weight of a straight-chain hydrogen-containing polysiloxane (B-2) as represented by formula (2-2), 10 parts by weight of a straight-chain organopolysiloxane (C-2) as represented by the aforementioned formula (3-2), 1.5 parts by weight of a photopolymerization initiator 1173 (D), 0.08 parts by weight of a Custer catalyst having a platinum content of 0.5% (E), 0.1 parts by weight of 1-ethynylcyclohexanol (F), and 1.5 parts by weight of KH570 (G) are mixed evenly and vacuum degassed to obtain an organic silicone encapsulant.

[0175] (ViMe2SiO 1 / 2 ) 0.13 (Me3SiO 1 / 2 ) 0.1 (MePhSiO 2 / 2 ) 0.03 (MAPSiO 3 / 2 ) 0.06 (PhSiO 3 / 2 ) 0.68 (1-2)

[0176] In formula (1-2), Vi represents a vinyl group, Me represents a methyl group, MAP represents a methacryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to silicon atoms, the molar percentage content of the vinyl group is 8.7 mole %, the molar percentage content of the phenyl group is 47.7 mole %, and the molar percentage content of the methacryloxypropyl group is 4.0 mole %.

[0177] (HMe2SiO 1 / 2 )(Ph2SiO 2 / 2 )(HMe2SiO 1 / 2 ) (2-2)

[0178] In formula (2-2), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 25 mol %.

[0179] (MAPMe2SiO 1 / 2 )(MePhSiO 2 / 2 ) 25 (MAPMe2SiO 1 / 2 ) (3-2)

[0180] In formula (3-2), Me represents a methyl group, Ph represents a phenyl group, MAP represents a methacryloxypropyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 44.6 mol %.

[0181] <Example 3>

[0182] 100 parts by weight of a branched alkenyl-containing polysiloxane (A-3) as represented by formula (1-3), 22 parts by weight of a straight-chain hydrogen-containing polysiloxane (B-3) as represented by formula (2-3), 10 parts by weight of a straight-chain organopolysiloxane (C-3) as represented by formula (3-3), 1.5 parts by weight of a photopolymerization initiator 1173 (D), 0.08 parts by weight of a Custer catalyst having a platinum content of 0.5% (E), 0.1 parts by weight of 1-ethynylcyclohexanol (F), and 1.5 parts by weight of KH570 (G) are mixed evenly and vacuum degassed to obtain an organic silicone encapsulant.

[0183] (ViMe2SiO 1 / 2 ) 0.10 (Me3SiO 1 / 2 ) 0.12 (Me2SiO 2 / 2 ) 0.082 (APSiO 3 / 2 ) 0.03 (PhSiO 3 / 2 ) 0.618 (SiO 4 / 2 ) 0.05 (1-3)

[0184] In formula (1-3), Vi represents a vinyl group, Me represents a methyl group, AP represents an acryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to the silicon atom, the molar percentage content of the vinyl group is 6.6 mole %, the molar percentage content of the phenyl group is 40.7 mole %, and the molar percentage content of the acryloxypropyl group is 2.0 mole %.

[0185] (HPh2SiO 1 / 2 )(Me2SiO 2 / 2 )(HPh2SiO 1 / 2 ) (2-3)

[0186] In formula (2-3), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 50 mol %.

[0187] (APMe2SiO 1 / 2 )(Ph2SiO 2 / 2 ) 10 (Me2SiO 2 / 2 )6(APMe2SiO 1 / 2 ) (3-3)

[0188] In formula (3-3), Me represents a methyl group, Ph represents a phenyl group, AP represents an acryloxypropyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 52.6 mol %.

[0189] <Comparative Example 1>

[0190] 100 parts by weight of a branched alkenyl-containing polysiloxane (A-1′) as shown in formula (1-1′), 35 parts by weight of a straight-chain hydrogen-containing polysiloxane (B-1) as shown in formula (2-1), 10 parts by weight of a straight-chain organic polysiloxane (C-1′) as shown in formula (3-1′), 0.08 parts by weight of a Custer catalyst (E) having a platinum content of 0.5%, 0.1 parts by weight of 1-ethynylcyclohexanol (F), and 1.5 parts by weight of KH570 (G) are mixed evenly and vacuum degassed to obtain an organic silicone encapsulant.

[0191] (ViMe2SiO 1 / 2 ) 0.15 (Me3SiO 1 / 2 ) 0.10 (PhSiO 3 / 2 ) 0.75 (1-1′)

[0192] In formula (1-1′), Vi represents a vinyl group, Me represents a methyl group, and Ph represents a phenyl group, and among all substituents bonded to silicon atoms, the molar percentage content of the vinyl group is 10 molar %, the molar percentage content of the phenyl group is 50 molar %, and the molar percentage content of the acryloxypropyl group is 0 molar %.

[0193] (HMe2SiO 1 / 2 )(Ph2SiO 2 / 2 )2(HMe2SiO 1 / 2 ) (2-1)

[0194] In formula (2-1), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 40 mol %.

[0195] (ViMe2SiO 1 / 2 )(MePhSiO 2 / 2 ) 20 (ViMe2SiO 1 / 2 ) (3-1′)

[0196] In formula (3-1′), Vi represents a vinyl group, Me represents a methyl group, and Ph represents a phenyl group. Among all substituents bonded to silicon atoms, the molar percentage content of the vinyl group is 10 mol 4.3%, and the molar percentage content of the phenyl group is 43.6 mol %.

[0197] <Comparative Example 2>

[0198] 100 parts by weight of a branched alkenyl-containing polysiloxane (A-1) as represented by formula (1-1), 35 parts by weight of a straight-chain hydrogen-containing polysiloxane (B-1) as represented by formula (2-1), 10 parts by weight of a straight-chain organic polysiloxane (C-1) as represented by formula (3-1), 1.5 parts by weight of a photopolymerization initiator 1173 (D), and 1.5 parts by weight of KH570 (G) are mixed evenly, and vacuum degassed to obtain a silicone encapsulant.

[0199] (ViMe2SiO 1 / 2 ) 0.15 (Me3SiO 1 / 2 ) 0.10 (APSiO 3 / 2 ) 0.05 (PhSiO 3 / 2 ) 0.70 (1-1)

[0200] In formula (1-1), Vi represents a vinyl group, Me represents a methyl group, AP represents an acryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to the silicon atom, the molar percentage content of the vinyl group is 10 mole %, the molar percentage content of the phenyl group is 46.7 mole %, and the molar percentage content of the acryloxypropyl group is 3.3 mole %.

[0201] (HMe2SiO 1 / 2 )(Ph2SiO 2 / 2 )2(HMe2SiO 1 / 2 ) (2-1)

[0202] In formula (2-1), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 40 mol %.

[0203] (APMe2SiO 1 / 2 )(MePhSiO 2 / 2 ) 20 (APMe2SiO 1 / 2 ) (3-1)

[0204] In formula (3-1), Me represents a methyl group, Ph represents a phenyl group, AP represents an acryloxypropyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 43.5 mol %.

[0205] <Comparative Example 3>

[0206] 100 parts by weight of a branched alkenyl-containing polysiloxane (A-1) as shown in formula (1-1), 35 parts by weight of a straight-chain hydrogen-containing polysiloxane (B-1) as shown in formula (2-1), 1.5 parts by weight of a photopolymerization initiator 1173 (D), 0.08 parts by weight of a Custer catalyst having a platinum content of 0.5% (E), 0.1 parts by weight of 1-ethynylcyclohexanol (F), and 1.5 parts by weight of KH570 (G) are mixed evenly and vacuum degassed to obtain a silicone encapsulant.

[0207] (ViMe2SiO 1 / 2 ) 0.15 (Me3SiO 1 / 2 ) 0.10 (APSiO 3 / 2 ) 0.05 (PhSiO 3 / 2 ) 0.70 (1-1)

[0208] In formula (1-1), Vi represents a vinyl group, Me represents a methyl group, AP represents an acryloxypropyl group, and Ph represents a phenyl group, and among all substituents bonded to the silicon atom, the molar percentage content of the vinyl group is 10 mole %, the molar percentage content of the phenyl group is 46.7 mole %, and the molar percentage content of the acryloxypropyl group is 3.3 mole %.

[0209] (HMe2SiO 1 / 2 )(Ph2SiO 2 / 2 )2(HMe2SiO 1 / 2 ) (2-1)

[0210] In formula (2-1), Ph represents a phenyl group, Me represents a methyl group, and the molar percentage content of the phenyl group in all substituents bonded to the silicon atom is 40 mol %.

[0211] Table 1

[0212]

[0213]

[0214] The test results in Table 1 show that the organosilicon encapsulants prepared in Examples 1 to 3 all use branched alkenyl-containing polysiloxanes with alkenyl groups, photopolymerizable groups and aromatic groups, linear hydrogen-containing polysiloxanes with aromatic groups and linear organopolysiloxanes with aromatic groups and photopolymerizable groups as base resins, and are used in combination with photopolymerization initiators and hydrosilylation catalysts that do not show catalytic activity when irradiated with ultraviolet rays. The organosilicon encapsulants prepared in Examples 1 to 3 have dynamic viscosities of 4150 mPa∙s, 3210 mPa∙s and 2350 mPa∙s at 25°C, respectively; and also have good staged curing characteristics, that is, they can be photocured first to form a photocured encapsulation layer, and then thermally cured to form a thermally cured encapsulation layer. In addition, the surface of the heat-cured encapsulation layer is smooth and flat, the thickness error of the cured film is within ±8%, the hardness is Shore 52D, Shore 45D, and Shore 38D respectively, the 450nm transmittance is greater than 99%, the 450nm transmittance maintenance rate at 150℃*1000 hours is greater than 95%, the 450nm transmittance maintenance rate under xenon lamp*1000 hours is greater than 90%, the tensile strength is greater than 3MPa, and the elongation at break is greater than 50%.

[0215] The main difference between Comparative Example 1 and Example 1 is that the branched alkenyl-containing polysiloxane and the linear organopolysiloxane used in the organosilicon encapsulant prepared in Comparative Example 1 do not contain photopolymerizable groups and no photopolymerization initiator is used. The organosilicon encapsulant prepared in Comparative Example 1 does not have the staged curing characteristics, that is, it cannot be photocured, but can only be thermally cured, and the surface of the encapsulation layer formed by the final curing has pits and wrinkles, and the thickness error of the cured film is as high as ±18.8%.

[0216] The main difference between Comparative Example 2 and Example 1 is that the silicone encapsulant prepared in Comparative Example 2 does not use a hydrosilylation catalyst that does not show catalytic activity when irradiated with ultraviolet rays. It also does not have the characteristics of staged curing, that is, it can only be photocured, not thermally cured, and the surface of the encapsulation layer formed by the final curing has pits and wrinkles, the thickness error of the cured film is as high as ±25.1%, the hardness is only Shore 33A, the light transmittance maintenance rate of 450nm at 150℃*1000 hours is 94.4%, the light transmittance maintenance rate of 450nm at xenon lamp*1000 hours is 87.0%, and the elongation at break is only 35%, showing lower hardness and worse appearance evaluation, thickness uniformity, light and heat aging resistance and mechanical properties than Example 1.

[0217] The main difference between Comparative Example 3 and Example 1 is that the organic silicone encapsulant prepared in Comparative Example 3 does not use a linear organic polysiloxane with an aromatic group and a photopolymerizable group. The dynamic viscosity of the organic silicone encapsulant prepared in Comparative Example 3 is as high as 5280 mPa∙s at 25°C, showing a higher viscosity than Example 1. Moreover, although it has a staged curing characteristic, that is, it can be photocured first to form a photocured encapsulation layer, and then thermally cured to form a thermally cured encapsulation layer, the thickness error of the cured film of the encapsulation layer formed by the final curing is ±10.5%, the hardness is as high as Shaw 68D, the xenon lamp * 1000 hours 450nm light transmittance maintenance rate is only 86.2%, and the elongation at break is only 28%, showing higher hardness and worse thickness uniformity, light and heat aging resistance and mechanical properties than Example 1.

[0218] In summary, the present invention uses a branched alkenyl-containing polysiloxane with alkenyl, photopolymerizable groups and aromatic groups, a linear hydrogen-containing polysiloxane with aromatic groups and a linear organopolysiloxane with aromatic groups and photopolymerizable groups as a matrix resin, and uses them in combination with a photopolymerization initiator and a hydrosilylation catalyst that does not show catalytic activity when irradiated with ultraviolet rays. The organic silicone encapsulant prepared thereby has suitable viscosity and good staged curing characteristics, that is, it can be photocured first to form a photocured encapsulation layer, and then thermally cured to form a thermally cured encapsulation layer; and the thermally cured encapsulation layer has a flat surface, uniform thickness, moderate hardness, and also has good light transmittance, light and heat aging resistance and mechanical properties. Thus, micro LED components and optical display devices with good encapsulation performance can be prepared.

[0219] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any deformation, improvement and substitution that can be conceived by those skilled in the art shall fall within the scope of the present invention.

Claims

1. A silicone encapsulant for micro LED components, characterized in that: It contains: (A) 100 parts by weight of a branched alkenyl-containing polysiloxane having a structure represented by formula (1): (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R1SiO 3 / 2 ) c (SiO 4 / 2 ) d (1) In formula (1), a, b, c, and d represent molar ratios, and 0<a<1, 0≤b<1, 0≤c<1, 0≤d<0.6, a+b+c+d=1 and c+d>0; each R 1 independently represent an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a photopolymerizable group, and in all R 1 The molar percentage content of alkenyl in the total R 1 The molar percentage content of aromatic groups in the 1 The molar percentage content of the photopolymerizable groups is 0.5 mol % to 20 mol %; (B) 5 to 50 parts by weight of a linear hydrogen-containing polysiloxane having a structure represented by formula (2): (R 2 3SiO 1 / 2 )(R 2 2SiO 2 / 2 ) m (R 2 3SiO 1 / 2 ) (2) In formula (2), m represents the degree of polymerization, and m is an integer from 1 to 20; each R 2 independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms, wherein at least two R 2 is a hydrogen atom, and in all R 2 The molar percentage content of aromatic groups is 10 mol % to 70 mol %; (C) 1 to 30 parts by weight of a linear organopolysiloxane having a structure represented by formula (3): (R 3 3SiO 1 / 2 )(R 3 2SiO 2 / 2 ) n (R 3 3SiO 1 / 2 ) (3) In formula (3), n represents the degree of polymerization, and n is an integer from 1 to 50; each R 3 independently represent an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a photopolymerizable group, wherein at least two R 3 is a photopolymerizable group, and in all R 3 The molar percentage content of aromatic groups is 10 mol % to 70 mol %; (D) 0.01 to 5 parts by weight of a photopolymerization initiator; (E) 0.001 to 5 parts by weight of a hydrosilylation catalyst, The hydrosilylation catalyst is selected from a platinum-containing compound or a rhodium-containing compound; The platinum compound is selected from chloroplatinic acid, a reaction product of chloroplatinic acid and an alcohol, a platinum-olefin complex, a platinum-vinylsilane complex, a platinum-ketone complex and a platinum-phosphine complex; The rhodium-containing compound is selected from rhodium-phosphine complexes and rhodium-sulfur compound complexes; palladium-containing compounds, such as palladium-phosphine complexes; The hydrosilylation catalyst does not show catalytic activity when irradiated with ultraviolet rays; In formula (1) and formula (3), the photopolymerizable group is an acryloyloxypropyl group or a methacryloyloxypropyl group.

2. The organic silicon encapsulant according to claim 1, characterized in that: It further comprises: (F) a hydrosilylation inhibitor or (G) an adhesion promoter.

3. The organic silicon encapsulant according to claim 1 or 2, characterized in that: The dynamic viscosity of the organic silicon encapsulation adhesive at 25° C. is 500 mPa∙s to 10000 mPa∙s.

4. A method for packaging a micro LED component, comprising: (S1) coating step: coating the silicone encapsulant according to any one of claims 1 to 3 on the surface of the micro LED element to form an uncured encapsulation layer; (S2) a photocuring step: photocuring the uncured encapsulation layer to form a photocured encapsulation layer; (S3) Thermal curing step: thermally curing the photocured encapsulation layer to form a thermally cured encapsulation layer.

5. The packaging method according to claim 4, characterized in that: The micro LED element is a micro LED element or a mini LED element.

6. The packaging method according to claim 4, characterized in that: The photocuring is performed under the irradiation of ultraviolet light with a wavelength of 250nm to 380nm.

7. The packaging method according to any one of claims 4 to 6, characterized in that: The thermal curing is performed at a temperature of 50°C to 200°C.

8. A packaged micro LED component, characterized in that: The micro LED device is obtained by packaging a micro LED device using the packaging method of a micro LED device according to any one of claims 4 to 7.

9. An optical display device, characterized in that: It comprises the packaged micro LED element according to claim 8.

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