A silicone-modified polyimide resin composition and use thereof

Abstract

Disclosed is a silicone-modified polyimide resin composition comprising a silicone-modified polyimide, a thermal curing agent, wherein the silicone-modified polyimide contains a repeating unit represented by the following general formula (I): in the general formula (I), Ar 1 is a tetravalent organic group having a benzene ring or alicyclic hydrocarbon structure, Ar 2 is a divalent organic group, R is independently selected from a methyl group or a phenyl group, and the thermal curing agent is an epoxy resin, an isocyanate, or a bisoxazoline compound. The silicone-modified polyimide resin composition obtained by the present application has excellent heat resistance, mechanical strength, and light transmittance.

Description

[0001] This invention application is a divisional application filed with the Chinese Patent Office on September 18, 2018, with application number 201811097472.8 and the invention title "An Organosilicon Modified Polyimide Resin Composition and Its Application". Technical Field

[0002] This invention relates to the field of lighting, and more particularly to a silicone-modified polyimide resin composition. Background Technology

[0003] LEDs are gradually replacing traditional lighting fixtures due to their advantages of being environmentally friendly, energy-saving, highly efficient, and long-lasting. However, traditional LED light sources emit light in a directional manner, unlike traditional lamps which can provide wide-angle illumination. In recent years, the development of filaments that enable LED light sources to emit light similarly to traditional tungsten filament lamps, achieving 360° omnidirectional illumination, has gained industry attention.

[0004] Patent publication number CN103994349A discloses a high-efficiency LED lamp, in which multiple LED chips are fixed on a transparent substrate with filament electrodes at both ends. The transparent substrate is made of transparent glass, microcrystalline glass, transparent ceramic, yttrium aluminum garnet, alumina (sapphire), chlorine oxynitride, yttrium oxide ceramic, calcium oxide ceramic, or transparent heat-resistant PC / PS / PMMA. Although using this transparent substrate can avoid the blue light loss caused by the downward blue light emitted by the LED chips returning through the PN junction, this substrate is a rigid substrate and cannot be bent, thus having the disadvantage of a small light emission angle.

[0005] Patent publication number CN204289439U discloses an omnidirectional LED filament, comprising a substrate mixed with phosphor, electrodes disposed on the substrate, at least one LED chip mounted on the substrate, and encapsulating adhesive covering the LED chip. The substrate, formed from phosphor-containing silicone resin, eliminates the cost of using glass or sapphire as a substrate. The filament made using this substrate avoids the influence of glass or sapphire on the light emission of the chip, achieving 360-degree light emission and significantly improving light uniformity and luminous efficiency. However, because the substrate is formed from silicone resin, it suffers from poor heat resistance.

[0006] This application is a further optimization of the above application to better meet various process requirements. Summary of the Invention

[0007] The main technical problem solved by this invention is to provide an organosilicon-modified polyimide resin composition. Using this composition as a filament substrate or light conversion layer can solve the problems of poor heat resistance of existing substrates and unstable performance / light emission of filament products.

[0008] An LED bulb lamp is provided, including a lamp housing and a lamp head connected to the lamp housing. The lamp housing is provided with at least two conductive supports, a driving circuit, a cantilever, a core post and an LED filament. The driving circuit is electrically connected to the conductive supports and the lamp head. The LED filament is connected to the core post through the conductive supports. The LED filament is characterized in that the LED filament includes a plurality of LED chips and a light conversion layer coated on at least two sides of the LED chips. The light conversion layer includes a top layer and a base layer.

[0009] A composite film made of organosilicon-modified polyimide resin was used as the substrate for LED filaments.

[0010] The base layer is a composite film made of organosilicon-modified polyimide resin composition;

[0011] The silicone-modified polyimide resin composition includes silicone-modified polyimide, a thermosetting agent, phosphor, and heat dissipation particles;

[0012] The heat dissipation particles include particles with high light transmittance and particles with low light transmittance, and the weight ratio of the particles with high light transmittance to the particles with low light transmittance is 3 to 5:1.

[0013] The organosilicon-modified polyimide contains repeating units represented by the following general formula (Ⅰ):

[0014] (Ⅰ);

[0015] In general formula (Ⅰ), R is selected from methyl or phenyl, and n is 1 to 5;

[0016] Ar1 is a tetravalent organic group having a benzene ring structure or an alicyclic hydrocarbon structure containing an active hydrogen functional group, wherein the active hydrogen functional group is any one of hydroxyl, amino, carboxyl or thiol groups;

[0017] Ar2 is a divalent organic group containing an active hydrogen functional group, wherein the active hydrogen functional group is any one of hydroxyl, amino, carboxyl or thiol groups;

[0018] The siloxane content of the organosilicon-modified polyimide is 30-70 wt%, and the siloxane content is the weight ratio of siloxane-type diamine to organosilicon-modified polyimide. The weight of organosilicon-modified polyimide is the sum of the weights of the diamine and dianhydride used in the synthesis of organosilicon-modified polyimide minus the weight of water generated during the synthesis process.

[0019] In one embodiment of the present invention, the thermosetting agent is any one of epoxy resin, isocyanate, bismaleimide and bisoxazoline compound.

[0020] In one embodiment of the present invention, the phosphor is spherical, plate-shaped, or needle-shaped.

[0021] In one embodiment of the present invention, the amount of phosphor used is not less than 0.05 times and not more than 8 times the weight of the organosilicon-modified polyimide.

[0022] In one embodiment of the present invention, the phosphor includes red phosphor and green phosphor, and the addition ratio of red phosphor to green phosphor is 1:5 to 8.

[0023] In one embodiment of the present invention, the phosphor includes red phosphor and yellow phosphor, and the addition ratio of red phosphor to yellow phosphor is 1:5 to 8.

[0024] In one embodiment of the present invention, an additive is added during the synthesis process of the silicone-modified polyimide resin composition. The additive is a defoamer, leveling agent or adhesive, and the amount of the additive is no more than 10% of the weight of the silicone-modified polyimide.

[0025] In one embodiment of the present invention, the amount of phosphor used is greater than or equal to 0.05 times the weight of the organosilicon-modified polyimide.

[0026] In one embodiment of the present invention, the heat dissipation particles are any one or a combination of one or more of silicon dioxide, aluminum oxide, magnesium oxide, magnesium carbonate, aluminum nitride, boron nitride, and diamond.

[0027] In one embodiment of the present invention, the organosilicon-modified polyimide includes fluorinated aromatic organosilicon-modified polyimide and aliphatic organosilicon-modified polyimide.

[0028] In one embodiment of the present invention, the Ar1 in the organosilicon-modified polyimide is derived from dianhydride, and the Ar2 is derived from diamine.

[0029] In one embodiment of the present invention, the average particle size of the heat dissipation particles is 1 / 5 to 2 / 5 times the thickness of the substrate.

[0030] In one embodiment of the present invention, the substrate includes an upper surface and a lower surface opposite to the upper surface. The upper surface of the substrate includes a first region and a second region. The second region includes pores. The surface roughness of the first region is less than that of the second region.

[0031] In one embodiment of the present invention, the lower surface of the substrate includes a third region, the surface roughness of the third region being greater than that of the first region.

[0032] In one embodiment of the present invention, the composite film of the organosilicon-modified polyimide resin composition has an elongation at break greater than 0.5% and an elastic modulus greater than 2.0 GPa.

[0033] In one embodiment of the present invention, the refractive index of the silicone-modified polyimide resin composition composite film is 1.4 to 1.7.

[0034] In one embodiment of the present invention, the organosilicon-modified polyimide resin composition composite film is provided with pores, and the pores scatter the light emitted by the LED chip.

[0035] In one embodiment of the present invention, the volume ratio of the foam cells to the composite film of the organosilicon-modified polyimide resin composition is 5-20%.

[0036] Compared with the prior art, the present invention includes any of the following effects or any combination thereof:

[0037] (1) The silicone-modified polyimide resin composition obtained by adding thermosetting agents, light-transmitting particles, etc., with silicone-modified polyimide as the main body has excellent heat resistance, mechanical strength and light transmittance.

[0038] (2) The silicone-modified polyimide resin composition is used as the filament substrate. The filament has good flexibility, which allows the filament to present a variety of shapes and realize 360° omnidirectional lighting.

[0039] (3) Vacuum degassing or amidation reaction under nitrogen atmosphere is used to make the volume content percentage of the foam in the organosilicon modified polyimide 5-20%. After the light emitted by the LED chip is refracted by the bubbles, the light output is more uniform. Attached Figure Description

[0040] Figure 1 The graphs show the TMA analysis of polyimide before and after the addition of the thermosetting agent;

[0041] Figure 2A SEM image of an embodiment of a silicone-modified polyimide resin composite film (substrate);

[0042] Figure 2B SEM image of an embodiment of a silicone-modified polyimide resin composite film (substrate);

[0043] Figure 3 A cross-sectional schematic diagram of a silicone-modified polyimide resin composite film (substrate);

[0044] Figure 4 This is a three-dimensional partial cross-sectional schematic diagram of an embodiment of the LED filament of the present invention;

[0045] Figure 5 This is a cross-sectional schematic diagram of an embodiment of the filament layered structure of the present invention;

[0046] Figure 6 This is a three-dimensional schematic diagram of the LED bulb of the present invention. Detailed Implementation

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0048] This invention provides an organosilicon-modified polyimide comprising repeating units represented by the following general formula (Ⅰ):

[0049]

[0050] In general formula (Ⅰ), Ar 1 The organic group is a tetravalent organic group. The organic group has a benzene ring or an alicyclic hydrocarbon structure. The alicyclic hydrocarbon structure can be a monocyclic alicyclic hydrocarbon structure or an alicyclic hydrocarbon structure containing a bridged ring. As an alicyclic hydrocarbon structure containing a bridged ring, it can be a bicyclic alicyclic hydrocarbon structure or a tricyclic alicyclic hydrocarbon structure. The organic group can also be a benzene ring structure or an alicyclic hydrocarbon structure containing an active hydrogen functional group, which is any one or more of a hydroxyl, amino, carboxyl, or thiol group. In other embodiments, the active hydrogen functional group can also be an amide group.

[0051] Ar 2 The organic group is a divalent organic group, which may have, for example, an alicyclic hydrocarbon structure of a monocyclic system, and preferably a divalent organic group containing an active hydrogen functional group, which is any one or more of a hydroxyl, amino, carboxyl, or thiol group. In other embodiments, the active hydrogen functional group may also be an amide group.

[0052] R is independently selected from methyl or phenyl.

[0053] n can be 1 to 5, with n preferably being 1, 2, 3 or 5.

[0054] The number-average molecular weight of general formula (I) is 5,000 to 100,000, preferably 10,000 to 60,000, and more preferably 20,000 to 40,000. The number-average molecular weight is a polystyrene conversion value based on a calibration curve prepared using a gel permeation chromatography (GPC) apparatus with standard polystyrene.

[0055] Ar 1 It is a component derived from dianhydrides, which may include aromatic anhydrides and aliphatic anhydrides. Aromatic anhydrides include aromatic anhydrides containing only a benzene ring, fluorinated aromatic anhydrides, aromatic anhydrides containing an amide group, aromatic anhydrides containing an ester group, aromatic anhydrides containing an ether group, aromatic anhydrides containing a sulfur group, aromatic anhydrides containing a sulfone group, and aromatic anhydrides containing a carbonyl group, etc.

[0056] Examples of aromatic anhydrides containing only a benzene ring include pyromellitic anhydride (PMDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (aBPDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (sBPDA), and 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA); fluorinated aromatic anhydrides include, for example, 4,4'-(6FDA) (Hexafluoroisopropene) phthalic anhydride; aromatic anhydrides containing amide groups include N,N'-(5,5'-(perfluoropropyl-2,2-diyl)bis(2-hydroxy-5,1-phenylene))bis(1,3-dioxo-1,3-dihydroisobenzofuran)-5-carboxamide)(6FAP-ATA), N,N'-(9H-fluorene-9-ylidene-4,1-phenylene)bis[1,3-dihydro-1,3-dioxo-5- Isobenzofuran carboxamide (FDA-ATA), etc.; ester-containing aromatic anhydrides include p-phenyl bis(trimethacrylate) dianhydride (TAHQ), etc.; ether-containing aromatic anhydrides include 4,4'-(4,4'-isopropyldiphenoxy)bis(phthalic anhydride) (BPADA), 4,4'-oxobisphthalic anhydride (sODPA), and 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride (aODPA). 4,4'-(4,4'-isopropyldiphenoxy)bis(phthalic anhydride) (BPADA), etc.; sulfur-containing aromatic anhydrides include 4,4'-bis(phthalic anhydride) sulfide (TPDA), etc.; sulfone-containing aromatic anhydrides include 3,3',4,4'-diphenylsulfone tetracarboxylic anhydride (DSDA), etc.; carbonyl-containing aromatic anhydrides include 3,3',4,4'-benzophenone tetracarboxylic anhydride (BTDA), etc.

[0057] Alicyclic anhydrides include 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), 1,2,3,4-butanetetracarboxylic dianhydride (BDA), tetrahydro-1H-5,9-methanepyrano[3,4-d]oxin-1,3,6,8(4H)-tetraone (TCA), hexahydro-4,8-ethylene-1H,3H-benzo[1,2-C:4,5-C']difuran-1,3,5,7-tetraone (BODA), cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CpDA), etc., or alicyclic anhydrides with an olefinic structure, such as bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (COeDA). If an acid anhydride with an acetylene group, such as 4,4'-(acetylene-1,2-diyl)phthalic anhydride (EBPA), is used, the film strength of the light conversion layer can be further ensured through post-curing.

[0058] From a solubility perspective, 4,4'-oxophthalic anhydride (sODPA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), cyclobutanetetracarboxylic dianhydride (CBDA), and 4,4'-(hexafluoroisopropene) diacid anhydride (6FDA) are preferred. These dianhydrides can be used alone or in combination of two or more.

[0059] Ar 2 It is a component derived from diamines, which can be divided into aromatic diamines and aliphatic diamines. Aromatic diamines include aromatic diamines containing only benzene ring structures, fluorinated aromatic diamines, aromatic diamines containing ester groups, aromatic diamines containing ether groups, aromatic diamines containing amide groups, aromatic diamines containing carbonyl groups, aromatic diamines containing hydroxyl groups, aromatic diamines containing carboxyl groups, aromatic diamines containing sulfone groups, and aromatic diamines containing sulfur groups, etc.

[0060] Aromatic diamines containing only a benzene ring structure include m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,6-diamino-3,5-diethyltoluene, 4,4'-diamino-3,3'-dimethylbiphenyl, 9,9-bis(4-aminophenyl)fluorene (FDA), 9,9-bis(4-amino-3-tolyl)fluorene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-methyl-4-aminophenyl)propane, and 4,4'-diamino-2,2'-dimethylbiphenyl (APB); fluorinated aromatic diamines include 2,2'-bis(trifluoromethyl)diaminobiphenyl (TFMB) and 2,2-bis(4-aminophenyl)hexafluoropropane (6FDAM). 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), 2,2-bis(3-amino-4-tolyl)hexafluoropropane (BIS-AF-AF), etc.; ester-containing aromatic diamines include [4-(4-aminobenzoyl)oxyphenyl]-4-aminobenzoate (ABHQ), di-p-aminophenyl terephthalate (BPTP), p-aminophenyl p-aminobenzoate (APAB), etc.; ether-containing aromatic diamines include 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis[4-(4-aminophenoxyphenyl)]propane (ET-BDM), 2,7-bis(4- Aminophenoxy)-naphthalene (ET-2,7-Na), 1,3-bis(3-aminophenoxy)benzene (TPE-M), 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline] (p-6FAPB), 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (ODA), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(4-aminophenoxy)benzene (TPE-Q), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), etc.; aromatic diamines containing amide groups include N,N'-bis(4-aminophenyl)benzene-1,4-dicarboxamide (BPTPA), 3,4'- Diaminobenzoyl aniline (m-APABA), 4,4'-diaminobenzoyl aniline (DABA), etc.; carbonyl-containing aromatic diamines include 4,4'-diaminobenzophenone (4,4'-DABP), bis(4-amino-3-carboxyphenyl)methane (or 6,6'-diamino-3,3'-methylenedibenzoic acid), etc.; hydroxyl-containing aromatic diamines include 3,3'-dihydroxybenzidine (HAB), 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), etc.; carboxyl-containing aromatic diamines include 6,6'-diamino-3,3'-methylenedibenzoic acid (MBAA), 3,5-diaminobenzoic acid (DBA), etc.Sulfone-containing aromatic diamines include 3,3'-diaminodiphenyl sulfone (DDS), 4,4'-diaminodiphenyl sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS) (or 4,4'-bis(4-aminophenoxy)diphenyl sulfone), and 3,3'-diamino-4,4'-dihydroxydiphenyl sulfone (ABPS); sulfur-containing aromatic diamines include 4,4'-diaminodiphenyl sulfide.

[0061] Aliphatic diamines are diamines that do not contain aromatic structures (such as benzene rings). Alicyclic diamines include monocyclic alicyclic diamines and straight-chain alicyclic diamines. Straight-chain alicyclic diamines include siloxane diamines, straight-chain alkyl diamines, and straight-chain alicyclic diamines containing ether groups. Monocyclic alicyclic diamines include 4,4'-diaminodicyclohexylmethane (PACM) and 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC); siloxane diamines (or amino-modified diamines) Organosilicones include α,ω-(3-aminopropyl)polysiloxane (KF8010), X22-161A, X22-161B, NH15D, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (PAME), etc.; the number of carbon atoms in the linear alkyl diamine is 6 to 12, preferably unsubstituted linear alkyl diamines; the linear aliphatic diamines containing ether groups include ethylene glycol di(3-aminopropyl) ether, etc.

[0062] Diamines containing a fluorene group can also be selected. The fluorene group has a large free volume and a rigid fused ring structure, which enables polyimides to possess good heat resistance, thermal oxidation stability, mechanical properties, optical transparency, and good solubility in organic solvents. A fluorene-containing diamine, such as 9,9-bis(3,5-difluoro-4-aminophenyl)fluorene, can be obtained by reacting 9-fluorenone with 2,6-dichloroaniline. Fluorinated diamines can also be selected from 1,4-bis(3'-amino-5'-trifluoromethylphenoxy)biphenyl. This diamine is a meta-substituted fluorinated diamine with a rigid biphenyl structure. The meta-substitution structure can hinder charge flow along the molecular chain direction, reduce intermolecular conjugation, and thus reduce the absorption of visible light. Using diamines or anhydrides with asymmetric structures can improve the transparency of the composite film to some extent. The above diamines can be used alone or in combination of two or more.

[0063] Examples of diamines containing active hydrogen include hydroxyl-containing diamines such as 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dihydroxy-1,1'-biphenyl (or 3,3'-dihydroxybenzidine) (HAB), 2,2-bis(3-amino-4-hydroxyphenyl)propane (BAP), 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), and 1,3-bis(3-hydroxy-4-aminophenoxy)propane. Examples of diamines with a carboxyl group include 1,4-bis(3-hydroxy-4-aminophenyl)benzene, 3,3'-diamino-4,4'-dihydroxydiphenyl sulfone (ABPS), and others such as 3,5-diaminobenzoic acid, bis(4-amino-3-carboxyphenyl)methane (or 6,6'-diamino-3,3'-methylenedibenzoic acid), 3,5-bis(4-aminophenoxy)benzoic acid, and 1,3-bis(4-amino-2-carboxyphenoxy)benzene. Examples of diamines with an amino group include 4,4'-diaminobenzoyl aniline (DABA), 2-(4-aminophenyl)-5-aminobenzimidazole, diethylenetriamine, 3,3'-diaminodipropylamine, triethylenetetramine, N,N'-bis(3-aminopropyl)ethylenediamine (or N,N-di(3-aminopropyl)ethylethylamine), etc. Diamines containing thiol groups, such as 3,4-diaminophenylthiol. These diamines can be used alone or in combination of two or more.

[0064] Organosilicon-modified polyimides can be synthesized by known synthetic methods. Diacid anhydrides and diamines can be prepared by imidization in the presence of a catalyst in an organic solvent. Examples of catalysts include acetic anhydride / triethylamine type, valerol / pyridine type, etc. Preferably, the water produced during the azeotropic process of the imidization reaction is removed using a dehydrating agent (such as toluene).

[0065] Alternatively, an acid anhydride can be reacted with a diamine in an equilibrium reaction to obtain ammonium acid, which can then be heated and dehydrated to obtain polyimide. Furthermore, alicyclic acid anhydrides and diamines can be directly heated and dehydrated to obtain solution-formed polyimide. Using this solution-formed polyimide as a binder material results in better light transmittance, and since it is itself liquid, it allows for more uniform dispersion of other solid materials (such as inorganic heat dissipation particles and phosphors) within the binder.

[0066] In one embodiment, the silicone-modified polyimide is prepared by dissolving the polyimide obtained by heating and dehydrating the diamine and acid anhydride in a solvent with a siloxane-type diamine. In another embodiment, the reaction is carried out with the siloxane-type diamine in the amic-acid state before obtaining the polyimide.

[0067] Alternatively, an anhydride and diamine can be used to dehydrate and condense an imide compound, such as an anhydride and diamine in a molecular weight ratio of 1:1. In one example, 200 mmol of 4,4'-(hexafluoroisopropene)phthalic anhydride (6FDA), 20 mmol of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), 50 mmol of 2,2'-bis(trifluoromethyl)diaminobiphenyl (TFMB), and 130 mmol of aminopropyl-terminated poly(dimethylsiloxane) were used to obtain a PI synthesis solution.

[0068] The above method can yield polyimide compounds with amino-terminated groups, but other methods can also be used to prepare polyimide compounds with carboxyl-terminated groups. Furthermore, in the above reaction of acid anhydrides and diamines, when the acid anhydride backbone contains a carbon-carbon triple bond, the binding force of the carbon-carbon triple bond can strengthen its molecular structure; alternatively, a diamine containing a vinylsiloxane structure can be used.

[0069] The molar ratio of dianhydride to diamine is 1:1. The diamine containing active hydrogen functional groups accounts for 5–25% of the total diamine molar fraction. The preferred reaction temperature for synthesizing polyimide is 80–250°C, more preferably 100–200°C. The reaction time can be adjusted according to the batch size; for example, the reaction time to obtain 10–30 g of polyimide is 6–10 hours.

[0070] Organosilicon-modified polyimides include fluorinated aromatic organosilicon-modified polyimides and aliphatic organosilicon-modified polyimides. Fluorinated aromatic organosilicon-modified polyimides are synthesized from siloxane-type diamines, aromatic diamines containing fluorine (F) groups (or fluorinated aromatic diamines), and aromatic dianhydrides containing fluorine (F) groups (or fluorinated aromatic anhydrides). Aliphatic organosilicon-modified polyimides are synthesized from dianhydrides, siloxane-type diamines, and at least one diamine without aromatic structures (such as benzene rings) (or aliphatic diamines), or diamines (one of which is a siloxane-type diamine) and at least one dianhydride without aromatic structures (such as benzene rings) (or aliphatic anhydrides). The raw materials required for synthesizing organosilicon-modified polyimides and the silica content of the organosilicon-modified polyimides all have a certain influence on the transmittance, color change properties, mechanical properties, warpage, and refractive index of the substrate.

[0071] The organosilicon-modified polyimide of the present invention has a siloxane content of 20–75 wt%, preferably 30–70 wt%, and a glass transition temperature of below 150°C. In the present invention, the siloxane content is the weight ratio of a siloxane-type diamine (structural formula as shown in formula (A)) to the organosilicon-modified polyimide. The weight of the organosilicon-modified polyimide is the sum of the weights of the diamine and dianhydride used in the synthesis of the organosilicon-modified polyimide, minus the weight of water generated during the synthesis process.

[0072]

[0073] R is selected from methyl or phenyl; R is preferably methyl, and n is 1 to 5, preferably 1, 2, 3, 5.

[0074] The organic solvent required for synthesizing silicone-modified polyimide only needs to be able to dissolve the silicone-modified polyimide and ensure affinity (wetting) with the phosphor or filler to be added. However, excessive solvent residue in the product should be avoided. Generally, the molar amount of solvent is equal to the molar amount of water produced by the diamine and acid anhydride. For example, 1 mol of diamine reacts with 1 mol of acid anhydride to produce 1 mol of water, so the amount of solvent used is 1 mol. Furthermore, the selected organic solvent should have a boiling point above 80°C and below 300°C at standard atmospheric pressure, preferably above 120°C and below 250°C. This is because drying and curing at low temperatures are required after coating. If the temperature is below 120°C, the drying speed may be too fast during the coating process, resulting in poor coating. If the boiling point of the selected organic solvent is above 250°C, drying at low temperatures may be delayed. Specifically, the organic solvent can be an ether, ester, dimethyl ether, ketone, alcohol, aromatic hydrocarbon, or other solvents. Ether organic solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether (or ethylene glycol dibutyl ether), diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether (or diethylene glycol methyl ethyl ether), dipropylene glycol dimethyl ether or diethylene glycol dibutyl ether (diethylene glycol dibutyl ether), and diethylene glycol butyl methyl ether; ester organic solvents include acetates, including ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propyl acetate, propylene glycol diacetate, butyl acetate, isobutyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, benzyl acetate or butyl acetate. Carbitol acetate, and other ester solvents may include methyl lactate, ethyl lactate, butyl lactate, methyl benzoate, or ethyl benzoate; dimethyl ether solvents include triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether; ketone solvents include acetylacetone, methyl propyl ketone, methyl butyl ketone, methyl isobutyl ketone, cyclopentanone, acetylacetone, methyl propyl ketone, methyl isobutyl ketone, cyclopentanone, or 2-heptanone; alcohol solvents include butanol, isobutanol, pentanol, 4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxybutanol, or diacetone alcohol; aromatic hydrocarbon solvents include toluene or xylene; other solvents include γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, or dimethyl sulfoxide.

[0075] This invention provides a silicone-modified polyimide resin composition comprising the aforementioned silicone-modified polyimide and a thermosetting agent, wherein the thermosetting agent is an epoxy resin, isocyanate, or bisoxazoline compound. In one embodiment, the amount of thermosetting agent is 5-12% of the weight of the silicone-modified polyimide.

[0076] Adding a thermosetting agent can improve heat resistance and glass transition temperature. For example... Figure 1 As shown, A1 and A2 represent the curves before and after adding the thermosetting agent, respectively. Curves D1 and D2 are the values ​​of curves A1 and A2 calculated using their derivatives, representing the degree of change in curves A1 and A2. Figure 1 The TMA (thermomechanical analysis) results show that the curve of thermal deformation slows down after the addition of a thermosetting agent. Therefore, it can be concluded that adding a thermosetting agent can improve its heat resistance.

[0077] When silicone-modified polyimide undergoes a crosslinking reaction with a thermosetting agent, the thermosetting agent only needs to have organic groups that can react with the active hydrogen functional groups in the polyimide. The amount and type of thermosetting agent have a certain influence on the color change properties, mechanical properties, and refractive index of the substrate. Therefore, some thermosetting agents with better heat resistance and transmittance can be selected. Examples of thermosetting agents include epoxy resins, isocyanates, bismaleimides, or bisoxazoline compounds. Epoxy resins can be bisphenol A type epoxy resins, such as BPA, or silicone type epoxy resins, such as KF105, X22-163, and X22-163A, or alicyclic epoxy resins, such as 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate (2021P), EHPE3150, and EHPE3150CE. Through the bridging reaction of epoxy resin, a three-dimensional bridging structure is formed between the silicone-modified polyimide and the epoxy resin, thereby improving the structural strength of the adhesive material itself. In one embodiment, the amount of thermosetting agent can also be determined based on the molar amount of active hydrogen functional groups reacting with the thermosetting agent in the silicone-modified polyimide. In one embodiment, the molar amount of active hydrogen functional groups reacting with the thermosetting agent is equal to the molar amount of the thermosetting agent. For example, if the molar amount of active hydrogen functional groups reacting with the thermosetting agent is 1 mol, then the molar amount of the thermosetting agent is 1 mol.

[0078] The specific information about BPA is shown in Table 1:

[0079] Table 1

[0080]

[0081] The specific information for 2021P is shown in Table 2:

[0082]

[0083] Specific information about EHPE3150 and EHPE3150CE is shown in Table 3:

[0084] Table 3

[0085]

[0086] The specific information for PAME, KF8010, X22-161A, X22-161B, NH15D, X22-163, X22-163A, and KF-105 is shown in Table 4. The refractive index in Table 4 is also known as the refractive index.

[0087] Table 4

[0088]

[0089]

[0090] The organosilicon-modified polyimide resin composition may also contain phosphors to obtain the desired luminescent properties. Phosphors can convert the wavelength of light emitted by the light-emitting semiconductor; for example, yellow phosphors can convert blue light into yellow light, and red phosphors can convert blue light into red light. Examples of yellow phosphors include transparent phosphors such as (Ba,Sr,Ca)₂SiO₄:Eu and (Sr,Ba)₂SiO₄:Eu (barium orthosilicate (BOS)), and Y₃Al₅O₄. 12 Ce(YAG(Yttrium-aluminum-garnet):Ce), Tb3Al3O 12Silicate phosphors with silicate structures, such as Ce(YAG(terbium-aluminum-garnet):Ce), and nitride phosphors, such as Ca-α-SiAlON. Red phosphors include nitride phosphors, such as CaAlSiN3:Eu and CaSiN2:Eu. Green phosphors include rare earth-halate phosphors and silicate phosphors. The proportion of phosphor in the organosilicon-modified polyimide resin composition can be arbitrarily set according to the desired luminescence characteristics. Furthermore, when the organosilicon-modified polyimide resin composition is used as the filament substrate, the content, shape, and particle size of the phosphor in the composition will have a certain influence on the mechanical properties of the substrate (e.g., elastic modulus, elongation, tensile strength), warpage, and thermal conductivity. To ensure the substrate possesses superior mechanical properties, thermal conductivity, and low warpage, the phosphor contained in the silicone-modified polyimide resin composition is granular. The phosphor can be spherical, plate-like, or needle-like, with spherical shape being preferred. The maximum average length of the phosphor (average particle size when spherical) is 0.1 μm or more, preferably 1 μm or more, further preferably 1 to 100 μm, and more preferably 1 to 50 μm. The amount of phosphor is not less than 0.05 times the weight of the silicone-modified polyimide, preferably not less than 0.1 times, and not more than 8 times, preferably not more than 7 times. For example, if the weight of the silicone-modified polyimide is 100 parts by weight, the content of phosphor is not less than 5 parts by weight, preferably not less than 10 parts by weight, and not more than 800 parts by weight, preferably not more than 700 parts by weight. In one embodiment, when two phosphors are added simultaneously, such as red phosphor and green phosphor, the ratio of red phosphor to green phosphor is 1:5 to 8, preferably 1:6 to 7. In another embodiment, when two phosphors are added simultaneously, such as red phosphor and yellow phosphor, the ratio of red phosphor to yellow phosphor is 1:5 to 8, preferably 1:6 to 7.

[0091] The silicone-modified polyimide resin composition may further include heat-dissipating particles. The heat-dissipating particles in the silicone-modified polyimide resin composition of the present invention are preferably transparent powders, or particles with high light transmittance, or particles with high light reflectivity, because LED filaments are mainly used for light emission, and therefore the filament substrate needs to have good light transmittance. Furthermore, when mixing two or more types of heat-dissipating particles, a combination of particles with high light transmittance and particles with low light transmittance can be used, with the proportion of high-transmittance particles being greater than that of low-transmittance particles. For example, in one embodiment, the weight ratio of high-transmittance particles to low-transmittance particles is 3 to 5:1. To ensure that the substrate has superior tensile strength, elastic modulus, elongation, and thermal conductivity, the particle size distribution and mixing ratio of the heat-dissipating particles can be appropriately selected, such that the average particle size is in the range of 0.1 μm to 100 μm, preferably in the range of 1 μm to 50 μm. Examples of heat dissipation particles include silica, alumina, magnesium oxide, magnesium carbonate, aluminum nitride, boron nitride, or diamond. For dispersibility, silica, alumina, or a combination of both are preferred. Regarding the particle shape, the heat dissipation particles can be spherical, blocky, etc. Spherical shapes include those similar to spherical shapes. In one embodiment, spherical and non-spherical heat dissipation particles can be used to ensure both particle dispersibility and the thermal conductivity of the substrate. The ratio of spherical to non-spherical heat dissipation particles is 1:0.15 to 0.35. Regarding the particle size, for example, alumina with a particle size distribution of 0.1 to 100 μm and an average particle size of 12 μm, or alumina with a particle size distribution of 0.1 to 20 μm and an average particle size of 4.1 μm, can be used. This particle size distribution falls within the particle size range of alumina. In one embodiment, for substrate smoothness, the average particle size can be selected to be 1 / 5 to 2 / 5 of the substrate thickness, preferably 1 / 5 to 1 / 3. The amount of heat dissipation particles is 1 to 12 times the weight (amount) of the silicone-modified polyimide. For example, if the silicone-modified polyimide is 100 parts by weight, the content of heat dissipation particles is 100 to 1200 parts by weight, preferably 400 to 900 parts by weight. Two types of heat dissipation particles are added at the same time, such as silicon dioxide and alumina. The weight ratio of alumina to silicon dioxide is 0.4 to 25:1, preferably 1 to 10:1.

[0092] When synthesizing silicone-modified polyimide resin compositions, coupling agents (such as silane coupling agents) can be added to improve the adhesion between solid materials (such as phosphors, heat dissipation particles) and adhesives (such as silicone-modified polyimide) and to increase the overall dispersion uniformity of the solid materials, thereby improving the heat dissipation performance and film strength of the light conversion layer. Titanate coupling agents can also be used, preferably epoxy titanate coupling agents. The amount of coupling agent used is related to the amount of heat dissipation particles added and their specific surface area. The amount of coupling agent = (amount of heat dissipation particles * specific surface area of ​​heat dissipation particles) / minimum coating area of ​​the coupling agent. For example, when using an epoxy titanate coupling agent, the amount of coupling agent = (amount of heat dissipation particles * specific surface area of ​​heat dissipation particles) / 331.5.

[0093] In other specific embodiments of the present invention, to further improve the properties of the silicone-modified polyimide resin composition in the synthesis process, additives such as defoamers, leveling agents, or adhesives can be selectively added during the synthesis process of the silicone-modified polyimide resin composition, as long as they do not affect the lightfastness, mechanical strength, heat resistance, and colorfastness of the product. Defoamers are used to eliminate bubbles generated during printing, coating, and curing; for example, acrylic or silicone surfactants are used as defoamers. Leveling agents are used to eliminate unevenness on the coating surface generated during printing and coating. Specifically, it is preferable to contain 0.01–2 wt% surfactant components, which can suppress bubbles and make the coating smooth by using leveling agents such as acrylic or silicone; nonionic surfactants without ionic impurities are preferred. Examples of adhesives include imidazole compounds, thiazole compounds, triazole compounds, organoaluminum compounds, organotitanium compounds, and silane coupling agents. Preferably, the amount of these additives is no more than 10% of the weight of the silicone-modified polyimide. When the amount of additives exceeds 10 wt%, the physical properties of the resulting coating tend to decrease, and problems with lightfastness degradation caused by volatile components also arise.

[0094] The silicone-modified polyimide resin composition of the present invention can be used as a film or attached to a carrier as a substrate. The film formation process includes three steps: (a) coating step: spreading and coating the above-mentioned silicone-modified polyimide resin composition on a release liner to form a film; (b) drying and heating step: heating and drying the film together with the release liner to remove the solvent from the film; (c) peeling: after drying, peeling the film off the release liner to obtain the silicone-modified polyimide resin composition in film form. The release liner can be a centrifugal membrane or other materials that do not chemically react with the silicone-modified polyimide resin composition, such as a PET centrifugal membrane.

[0095] The silicone-modified polyimide resin composition is attached to a carrier to obtain a composition film, which can be used as a substrate. The formation process of the composition film includes two steps: (a) coating step: the above silicone-modified polyimide resin composition is spread and coated on the carrier to form a composition film; (b) drying and heating step: the composition film is heated and dried to remove the solvent in the film.

[0096] As a coating method in the coating process, roll-to-roll coating devices such as roller coaters, die coaters, and doctor blade coaters can be used, or simple coating methods such as printing, inkjet, dispensing, and spraying can be used.

[0097] The drying methods corresponding to the above-mentioned heating and drying processes can include vacuum drying, heating drying, etc. Heating methods can utilize heat sources such as electric heaters or heat transfer media to generate heat energy and induce indirect convection, or use infrared radiation emitted from a heat source for heating.

[0098] The aforementioned silicone-modified polyimide resin composition can be coated and then dried to obtain a highly thermally conductive film, achieving properties such as excellent light transmittance, chemical resistance, heat resistance, thermal conductivity, film mechanical properties, and lightfastness. The temperature and time used in the drying and curing process can be appropriately selected based on the solvent in the silicone-modified polyimide resin composition and the coating film thickness. Whether drying and curing is complete can be determined by the weight change of the silicone-modified polyimide resin composition before and after drying and curing, as well as the peak value change of the thermosetting agent functional groups in the infrared spectrum. For example, when epoxy resin is used as the thermosetting agent, the weight difference of the silicone-modified polyimide resin composition before and after drying and curing is equal to the weight of the added solvent and the increase or decrease in the peak value of the epoxy groups before and after drying and curing to determine whether drying and curing is complete.

[0099] In one embodiment, the amidation reaction is carried out under a nitrogen atmosphere, or a vacuum degassing method is used during the synthesis of the silicone-modified polyimide resin composition, or both methods are used, so that the volume percentage of bubbles in the silicone-modified polyimide resin composition film or the silicone-modified polyimide resin composition composite film is 5-20%, preferably 5-10%. The silicone-modified polyimide resin composition composite film is used as the substrate for the LED flexible filament, and the substrate 420b has an upper surface 420b1 and an opposite lower surface 420b2. Figures 2A-2B The image shown is a SEM image of different substrate surfaces, such as... Figures 2A-2B As shown, the substrate contains pores 4d, and the volume percentage of pores 4d in the substrate 420b is 5-20%, preferably 5-10%. The cross-section of the pores 4d is irregular in shape, such as... Figure 3 The image shown is a cross-sectional schematic diagram of substrate 420b. Figure 3The dashed line in the figure serves as a baseline. The upper surface 420b1 of the substrate includes a first region 4a and a second region 4b. The second region 4b includes a bubble 4d. The surface roughness of the first region 4a is less than that of the second region 4b. The light emitted by the LED chip is scattered through the bubble in the second region, resulting in more uniform light emission. The lower surface 420b2 of the substrate includes a third region 4c. The surface roughness of the third region 4c is greater than that of the first region 4a. When the LED chip is placed in the first region 4a, the relatively flat surface facilitates subsequent wire bonding. When the LED chip is placed in the second region 4b or the third region 4c, the contact area between the die bond adhesive and the substrate is large, which increases the bonding strength between the die bond adhesive and the substrate. Therefore, placing the LED chip on the upper surface 420b1 can simultaneously ensure both the die bonding and the bonding strength between the die bond adhesive and the substrate. When using silicone-modified polyimide resin composition film or silicone-modified polyimide resin composition composite film as LED flexible filament substrate, the light emitted by the LED chip is scattered by the bubbles in the substrate, resulting in more uniform light output and further improving glare.

[0100] When preparing silicone-modified polyimide resin compositions using a vacuum degassing method, the vacuum degree during degassing is -0.5 to -0.09 MPa, preferably -0.2 to -0.09 MPa. When the total weight of the raw materials used to prepare the silicone-modified polyimide resin composition is less than or equal to 250 g, the revolution speed is 1200–2000 rpm, the rotation speed is 1200–2000 rpm, and the vacuum degassing time is 3–8 min. This method maintains a certain amount of air bubbles in the film to increase the uniformity of light emission while preserving good mechanical properties. The vacuum degree can be appropriately adjusted according to the total weight of the raw materials required to prepare the silicone-modified polyimide resin composition; generally, the higher the total weight, the lower the vacuum degree can be, and the stirring time and speed can be appropriately increased.

[0101] According to the present invention, a resin with excellent light transmittance, chemical resistance, heat resistance to discoloration, thermal conductivity, film mechanical properties, and lightfastness, which is required as a substrate for LED flexible filaments, can be obtained. Furthermore, a high thermal conductivity resin film can be formed by simple coating methods such as printing coating, inkjet coating, or dispensing.

[0102] Aliphatic silicone-modified polyimide resin compositions include aliphatic silicone-modified polyimide and a thermosetting agent, while F-modified aromatic silicone-modified polyimide resin compositions include F-modified aromatic silicone-modified polyimide and a thermosetting agent. Because aliphatic silicone-modified polyimide has a cycloaliphatic structure, the film of the aliphatic silicone-modified polyimide resin composition has high light transmittance. When using a silicone-modified polyimide resin composite film as a filament substrate, to ensure good bending performance of the substrate, the elongation at break of the composite film should be greater than 0.5%, preferably 1-5%, and most preferably 1.5-5%. During filament fabrication, LED chips and electrodes are generally first fixed to the substrate using die-bonding adhesive, and then electrical connections are made between adjacent LED chips and between LED chips and electrodes using wires. To ensure die-bonding and wire bonding quality and improve product quality, the elastic modulus of the composite film should be greater than 2.0 GPa, preferably 2-6 GPa, and most preferably 4-6 GPa. Furthermore, when light emitted from an LED chip passes through the interface between two materials, the closer the refractive indices of the two materials are, the higher the light extraction efficiency. To approximate the refractive index of the material in contact with the substrate (or base layer) (e.g., die-attach adhesive), the refractive index of the silicone-modified polyimide composite film is 1.4–1.7, preferably 1.4–1.55. When using the silicone-modified polyimide resin composition in a filament substrate, the composition needs to have good transmittance at the peak wavelength of the InGaN used to excite a white LED. To obtain good transmittance, the raw materials, thermosetting agent, and heat dissipation particles used in the synthesis of the silicone-modified polyimide can be changed. Since the phosphor in the silicone-modified polyimide resin composition can affect the transmittance test, the silicone-modified polyimide resin composition used for transmittance measurement does not contain phosphor. The transmittance of this silicone-modified polyimide resin composition is 86–93%, preferably 88–91%, or more preferably 89–92%, or more preferably 90–93%.

[0103] When the silicone-modified polyimide resin composite film is used as a filament substrate (or base layer), the LED chip is a six-sided light emitter. During LED filament fabrication, at least two sides of the LED chip are wrapped by the top layer. Existing LED filaments exhibit uneven color temperature between the top and base layers when lit, or the base layer may appear grainy. Therefore, the composite film used as the filament substrate needs to possess excellent transparency. In other embodiments, sulfone groups, non-coplanar structures, meta-substituted diamines, etc., can be introduced into the main chain of the silicone-modified polyimide to improve the transparency of the silicone-modified polyimide resin composition. Furthermore, to enable the bulb using this filament to achieve omnidirectional light emission, the composite film used as the substrate needs to possess a certain degree of flexibility. Therefore, flexible structures such as ether groups (e.g., 4,4'-4-amino-2-trifluoromethylphenoxy)diphenyl ether, carbonyl groups, and methylene groups can be introduced into the main chain of the silicone-modified polyimide. In other embodiments, diamines or dianhydrides containing a pyridine ring can also be selected. The rigid structure of the pyridine ring can improve the mechanical properties of the composite membrane. At the same time, when used in conjunction with a strongly polar group (e.g., -F), the composite membrane can have excellent light transmittance. Anhydrides with a pyridine structure, such as 2,6-bis(3',4'-dicarboxyphenyl)-4-(3”,5”-bistrifluoromethylphenyl)pyridine dianhydride.

[0104] like Figure 4 As shown, the LED filament 100 includes multiple LED chips 102 and 104, at least two electrodes 110 and 112, and a light conversion layer 120. The light conversion layer 120 includes a binder 122 and wavelength conversion particles 124. The binder 122 can be replaced with polyimide or the aforementioned silicone-modified polyimide to have better toughness and reduce the probability of cracking or embrittlement. The light conversion particles in the light conversion layer 120 (which can be any light conversion material such as phosphor or dye; phosphor 124 is used as an example below) can absorb certain radiation (such as light) and emit light. The light conversion layer 120 may further have inorganic heat dissipation particles to increase heat dissipation capacity.

[0105] like Figure 5 As shown, the LED filament 400a includes: a light conversion layer 420; LED chips 402 and 404; electrodes 410 and 412; and gold wires 440 for electrically connecting the LED chips to the LED chips (or electrodes). The light conversion layer 420 is coated on at least both sides of the LED chips / electrodes. The light conversion layer 420 exposes a portion of the electrodes 410 and 412. The light conversion layer 420 may have at least a top layer 420a and a base layer 420b, serving as the upper and lower layers of the filament, respectively. In this embodiment, the top layer 420a and the base layer 420b are located on both sides of the LED chips / electrodes.

[0106] The top layer 420a is a layered structure with at least one layer. The layered structure can be selected from: a highly malleable phosphor adhesive, a low-malleability phosphor film, a transparent layer, or any layered combination of these three. The phosphor adhesive / phosphor film comprises the following components: adhesive 422, phosphor 424, and inorganic oxide nanoparticles 426. Adhesive 422 can be, but is not limited to, silicone. In one embodiment, adhesive 422 may contain 10% Wt or less of polyimide (hereinafter referred to as PI) to increase the overall hardness, insulation, thermal stability, and mechanical strength of the filament. The PI solid content can be 5-40% Wt, and the rotational viscosity can be 5-20 Pa·s. The inorganic oxide nanoparticles 426 can be, but is not limited to, alumina or aluminum nitride particles. The particle size can be 100-600 nanometers or 0.1 to 100 micrometers, and their function is to promote heat dissipation of the filament. The incorporated inorganic heat-dissipating particles can have various particle sizes. For example, the adhesive content of the phosphor film and phosphor adhesive can be adjusted to be greater than 20%, 50%, or 70% as needed. The Shore hardness of the phosphor adhesive can be D40-70; the thickness of the phosphor adhesive can be 0.2-1.5 mm; while the Shore hardness of the phosphor film can be D20-70. The thickness of the phosphor film can be 0.1-0.5 mm; the refractive index is 1.4 or higher; and the light transmittance is 40%-95%. The transparent layer (adhesive layer, insulating layer) can be composed of a high-transmittance resin such as silicone, PI, or a combination thereof. In one embodiment, the transparent layer can serve as a refractive index matching layer, which has the function of adjusting the filament light emission efficiency.

[0107] The base layer 420b is a layered structure with at least one layer, which can be selected from: highly malleable phosphor adhesive, low-malleability phosphor film, transparent layer, or any layered combination of the three; the phosphor adhesive / phosphor film contains the following components: silicone-modified polyimide 422', phosphor 424', and inorganic oxide nanoparticles 426'. In one embodiment, the silicone-modified polyimide can be replaced by the silicone-modified polyimide resin composition described above. The inorganic oxide nanoparticles 426 can be, but are not limited to, alumina or aluminum nitride particles, and the particle size can be 100-600 nanometers or 0.1 to 100 micrometers. Their function is to promote the overall heat dissipation of the filament, and the incorporated inorganic heat dissipation particles can have various particle sizes. The transparent layer (adhesive layer, insulating layer) can be composed of a high-transmittance resin such as silicone, silicone polyimide, or a combination thereof. In one embodiment, the transparent layer may serve as a refractive index matching layer, which has the function of adjusting the light extraction efficiency of the filament. In one embodiment, the base layer may be a composite film made of PI or the aforementioned silicone-modified polyimide resin composition.

[0108] like Figure 6As shown, the LED bulb 10c includes a lamp housing 12, a lamp holder 16 connected to the lamp housing 12, at least two conductive supports 14a and 14b disposed inside the lamp housing 12, a driving circuit 18, a cantilever 15, a core post 19, and a single LED filament 100. Conductive supports 14a and 14b are used to electrically connect the two electrodes 110 and 112 of the LED filament 100, and can also be used to support the weight of the LED filament 100. The LED filament 100 is connected to the core post 19 via the conductive supports 14a and 14b. The core post 19 can be used to replace the gas in the LED bulb 10b and provide heat conduction. The core post 19 also has a vertically extending pole 19a to the center of the lamp housing 12. A first end of each cantilever 15 is connected to the pole 19a, and a second end of each cantilever 15 is connected to the LED filament. The driving circuit 18 is electrically connected to the conductive supports 14a and 14b and the lamp holder 16. When the lamp holder 16 is connected to a conventional bulb socket, the socket provides power to the lamp holder 16, and the driving circuit 18 obtains power from the lamp holder 16 to drive the LED filament 100 to emit light. Since the LED filament 100 can emit light from its entire circumference, the entire LED bulb can produce omnidirectional light. LED filament 100 can be used Figures 5-6 Any one of the LED filaments mentioned above.

[0109] The definition of omnidirectional light described herein varies depending on the specific light bulb specifications of each country, and this definition may change over time. Therefore, the examples of omnidirectional light disclosed herein are not intended to limit the scope of this invention. For example, the US Energy Star Program Requirements for Lamps (Light Bulbs) provides a corresponding definition for the light pattern of bulb lamps (omnidirectional light bulbs). When a bulb lamp is configured with the base on top and the bulb facing down, the vertical top is 180 degrees and the vertical bottom is 0 degrees. It requires that the luminous intensity (cd) at each angle between 0 and 135 degrees should not differ from the average luminous intensity by more than 25%, and the total luminous flux (lm) between 135 and 180 degrees must account for at least 5% of the total luminous flux of the entire lamp. As another example, Japan's JEL 801 standard requires that the luminous flux of LED lamps within a 120-degree range be less than 70% of the total luminous flux.

[0110] The following embodiments are a further detailed description of the present invention, but are not intended to limit the scope of the invention.

[0111] Example 1: Preparation of Organosilicon-Modified Polyimide A-1 (Siloxane Content 41%)

[0112] In a reaction vessel equipped with a stirrer and a Deans Stark water separator, 62.04 g (200 mmol) of 4,4'-oxobisphthalic anhydride (sODPA), 32.84 g (80 mmol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 67.2 g (80 mmol) of α,ω-(3-aminopropyl)polysiloxane (KF8010), 8.64 g (40 mmol) of 3,3'-diamino-4,4'-dihydroxybiphenyl, 0.5 g of pyridine, 300 g of γ-butyrolactone (GBL), and 30 g of toluene were added. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 35% was obtained.

[0113] Example 2: Preparation of Organosilicon-Modified Polyimide A-2 (Siloxane Content 64%)

[0114] Using the same reaction vessel as in Example 1, 62.04 g (200 mmol) sODPA, 8.21 g (20 mmol) 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 126 g (150 mmol) α,ω-(3-aminopropyl)polysiloxane (KF8010), 6.48 g (30 mmol) 3,3'-diamino-4,4'-dihydroxybiphenyl, 0.5 g pyridine, 350 g γ-butyrolactone (GBL), and 30 g toluene were added to the reaction vessel. After stirring at 20 rpm for 30 min under a nitrogen atmosphere, the temperature was raised to 180 °C, and stirring was continued at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 37% was obtained.

[0115] Example 3: Preparation of Organosilicon Modified Polyimide A-3 (Siloxane Content 73%)

[0116] Using the same reaction vessel as in Example 1, 62.04 g (200 mmol) sODPA, 2.05 g (5 mmol) 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 171.6 g (165 mmol) NH15D (amino-modified organosilicon), 6.48 g (30 mmol) 3,3'-diamino-4,4'-dihydroxybiphenyl, 0.5 g pyridine, 350 g γ-butyrolactone (GBL), and 30 g toluene were added to the reaction vessel. After stirring at 20 rpm for 30 min under a nitrogen atmosphere, the temperature was raised to 180 °C, and stirring was continued at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, an organosilicon-modified polyimide with a solid content of 40% was obtained.

[0117] Example 4: Preparation of Organosilicon-Modified Polyimide A-4 (Siloxane Content 37%)

[0118] Using the same reaction vessel as in Example 1, 62.04 g (200 mmol) sODPA, 36.84 g (90 mmol) PACM, 58.8 g (70 mmol) KF8010 (amino-modified organosilicon), 9.08 g (40 mmol) 4,4'-diaminobenzoyl aniline (DABA), 0.5 g pyridine, 300 g γ-butyrolactone (GBL), and 30 g toluene were stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, an organosilicon-modified polyimide with a solid content of 44% was obtained.

[0119] Example 5: Preparation of Organosilicon-Modified Polyimide A-5 (Siloxane Content 45%)

[0120] Using the same reaction vessel as in Example 1, 39.26 g (200 mmol) of cyclobutanetetracarboxylic dianhydride (CBDA), 34.26 g (80 mmol) of 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline] (6FAPB), 67.2 g (80 mmol) of KF8010, 14.66 g (40 mmol) of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), 0.5 g of pyridine, 300 g of γ-butyrolactone (GBL), and 30 g of toluene were added to the reaction vessel. After stirring at 20 rpm for 30 min under a nitrogen atmosphere, the temperature was raised to 180 °C, and stirring was continued at 180 rpm for 4 h. During the reaction, the azeotropic fraction of toluene-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 45% was obtained.

[0121] Example 6: Preparation of Organosilicon-Modified Polyimide A-6 (Siloxane Content 44%)

[0122] Using the same reaction vessel as in Example 1, 62.04 g (200 mmol) sODPA, 16.82 g (80 mmol) 4,4'-diaminodicyclohexylmethane (PACM), 67.2 g (80 mmol) KF8010, 14.66 g (40 mmol) 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), 0.5 g pyridine, 300 g γ-butyrolactone (GBL), and 30 g toluene were added to the reaction vessel. After stirring at 20 rpm for 30 min under a nitrogen atmosphere, the temperature was raised to 180 °C, and stirring was continued at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 35% was obtained.

[0123] Example 7: Preparation of Organosilicon-Modified Polyimide A-7 (Siloxane Content 47%)

[0124] Using the same reaction vessel as in Example 1, 19.62 g (100 mmol) of cyclobutanetetracarboxylic dianhydride (CBDA), 31.0 g (100 mmol) of sODPA, 16.82 g (80 mmol) of PACM, 67.2 g (80 mmol) of KF8010, 14.66 g (40 mmol) of 4,4'-diaminobenzoyl aniline (DABA), 0.5 g of pyridine, 300 g of γ-butyrolactone (GBL), and 30 g of toluene were added to the reaction vessel. After stirring at 20 rpm for 30 min under a nitrogen atmosphere, the temperature was raised to 180 °C, and stirring was continued at 180 rpm for 4 h. During the reaction, the azeotropic fraction of toluene-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 33% was obtained.

[0125] Example 8: Preparation of Organosilicon-Modified Polyimide A-8 (Siloxane Content 44%)

[0126] Using the same reaction vessel as in Example 1, 88.86 g (200 mmol) of 4,4'-(hexafluoroisopropene)phthalic anhydride (6FDA), 21.42 g (50 mmol) of 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline] (6FAPB), 92.4 g (110 mmol) of KF8010, 14.66 g (40 mmol) of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), 0.5 g of pyridine, 300 g of γ-butyrolactone (GBL), and 30 g of toluene were added to the reaction vessel. After stirring at 20 rpm for 30 min under a nitrogen atmosphere, the temperature was raised to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 34% was obtained.

[0127] Example 9: Preparation of Organosilicon-Modified Polyimide A-9 (Siloxane Content 76%)

[0128] Using the same reaction vessel as in Example 1, 62.04 g (200 mmol) sODPA, 0.82 g (2 mmol) 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 185.12 g (178 mmol) NH15D (amino-modified organosilicon), 4.32 g (20 mmol) 3,3'-diamino-4,4'-dihydroxybiphenyl, 0.5 g pyridine, 350 g γ-butyrolactone (GBL), and 30 g toluene were added to the reaction vessel. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, an organosilicon-modified polyimide with a solid content of 41% was obtained.

[0129] Example 10: Preparation of Organosilicon Modified Polyimide A-10 (Siloxane Content 29%)

[0130] The same reaction vessel as in Example 1 was used. 62.04 g (200 mmol) sODPA, 39.38 g (110 mmol) 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 42.0 g (50 mmol) KF8010, 8.64 g (40 mmol) 3,3'-diamino-4,4'-dihydroxybiphenyl, 0.5 g pyridine, 300 g γ-butyrolactone (GBL), and 30 g toluene were added to the reaction vessel. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 33% was obtained.

[0131] Comparative Example 1: Preparation of a film made from an organosilicon-modified polyimide resin composition

[0132] The silicone-modified polyimide obtained in Example 1 was spread and coated onto a release liner using a doctor blade with a gap of 300 μm to form a film. The film was then dried at 100°C for 30 min to remove residual solvent, and then the temperature was adjusted to 160°C and dried for another 90 min to induce a curing reaction. After drying, the film was peeled off from the release liner to obtain a silicone-modified polyimide resin composition film.

[0133] Example 11 Preparation of silicone-modified polyimide resin composition film

[0134] The silicone-modified polyimides obtained in Examples 1-10 were mixed with epoxy resin and then subjected to vacuum degassing to obtain silicone-modified polyimide resin compositions. The degassing parameters were: vacuum degree -0.095 MPa, revolution speed 1500 rpm, rotation speed 1500 rpm, and vacuum degassing time 3 min. The silicone-modified polyimide resin composition was spread and coated onto a release liner using a doctor blade with a 300 μm gap to form a film. The film was then dried at 100°C for 30 min to remove residual solvent, and then the temperature was adjusted to 160°C and dried for another 90 min to induce a curing reaction. After drying, the film was peeled off from the release liner to obtain a silicone-modified polyimide resin composition film.

[0135] Example 12 Preparation of a composite film of organosilicon-modified polyimide resin composition

[0136] The silicone-modified polyimides obtained in Examples 1-10 were mixed with epoxy resin, phosphor, and alumina with a particle size distribution of 0.2-30 μm and an average particle size of 9.6 μm, respectively. Based on the silicone-modified polyimide, the phosphor content was 240% (i.e., 2.4 times the weight of the silicone-modified polyimide), with the addition ratio of (Ba,Sr,Ca)₂SiO₄:Eu to CaAlSiN₃:Eu being 7:1. Based on the weight of the silicone-modified polyimide, the alumina content was 560% (560 PHR) (i.e., 5.6 times the weight of the silicone-modified polyimide), and then a composite film was prepared using the method described in Example 11.

[0137] Example 13 Preparation of Organosilicon Modified Polyimide A-11 (Siloxane Content 44%)

[0138] Using the same reaction vessel as in Example 1, 100 mmol of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), 40 mmol of 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline] (6FAPB), 40 mmol of KF8010, 20 mmol of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), 0.25 g of pyridine, 100 g of γ-butyrolactone (GBL), and 45 g of methyl benzoate were added to the reaction vessel. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 185 °C and stirred at 170 rpm for 4 h. During the reaction, the azeotropic fraction of methyl benzoate-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 35% was obtained.

[0139] Example 14 Preparation of Organosilicon Modified Polyimide A-12 (Siloxane Content 42%)

[0140] Using the same reaction vessel as in Example 1, 100 mmol HPMDA, 40 mmol HFBAPP, 40 mmol KF8010, 20 mmol 6FAP, 0.25 g pyridine, 350 g γ-butyrolactone (GBL), and 45 g methyl benzoate were added to the reaction vessel. Under a nitrogen atmosphere, the mixture was stirred at 20 rpm for 30 min, then heated to 170 °C and stirred at 185 rpm for 4 h. During the reaction, the azeotropic portion of methyl benzoate-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 36% was obtained.

[0141] Example 15 Preparation of Organosilicon Modified Polyimide A-13 (Siloxane Content 50%)

[0142] Using the same reaction vessel as in Example 1, 100 mmol HPMDA, 40 mmol PACM, 40 mmol KF8010, 20 mmol 6FAP, 0.25 g pyridine, 350 g γ-butyrolactone (GBL), and 45 g methyl benzoate were added to the reaction vessel. Under a nitrogen atmosphere, the mixture was stirred at 20 rpm for 30 min, then heated to 170 °C and stirred at 185 rpm for 4 h. During the reaction, the azeotropic portion of methyl benzoate-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 32% was obtained.

[0143] Example 16 Preparation of Organosilicon Modified Polyimide A-14 (Siloxane Content 51%)

[0144] Using the same reaction vessel as in Example 1, 100 mmol HPMDA, 40 mmol PACM, 40 mmol KF8010, 20 mmol ABPS, 0.25 g pyridine, 350 g γ-butyrolactone (GBL), and 45 g methyl benzoate were added to the reaction vessel. Under a nitrogen atmosphere, the mixture was stirred at 20 rpm for 30 min, then heated to 170 °C and stirred at 185 rpm for 3.5 h. During the reaction, the azeotropic portion of methyl benzoate-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 32% was obtained.

[0145] Example 17 Preparation of Organosilicon Modified Polyimide A-15 (Siloxane Content 51%)

[0146] Using the same reaction vessel as in Example 1, 100 mmol HPMDA, 40 mmol PACM, 40 mmol KF8010, 20 mmol DABA, 0.25 g pyridine, 350 g γ-butyrolactone (GBL), and 45 g methyl benzoate were added to the reaction vessel. Under a nitrogen atmosphere, the mixture was stirred at 20 rpm for 30 min, then heated to 170 °C and stirred at 185 rpm for 4 h. During the reaction, the azeotropic portion of methyl benzoate-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 31% was obtained.

[0147] Example 18 Preparation of Organosilicon Modified Polyimide A-16 (Siloxane Content 40%)

[0148] Using the same reaction vessel as in Example 1, 50 mmol HPMDA, 50 mmol 6FDA, 40 mmol PACM, 40 mmol KF8010, 20 mmol 6FAP, 0.25 g pyridine, 350 g γ-butyrolactone (GBL), and 45 g methyl benzoate were added to the reaction vessel. Under a nitrogen atmosphere, the mixture was stirred at 20 rpm for 30 min, then heated to 170 °C and stirred at 185 rpm for 4 h. During the reaction, the azeotropic portion of methyl benzoate-water was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 35% was obtained.

[0149] Example 19 Preparation of Organosilicon Modified Polyimide A-17 (Siloxane Content 44%)

[0150] Using the same reaction vessel as in Example 1, 200 mmol of 6FDA, 50 mmol of 6FABP, 110 mmol of KF8010, 40 mmol of 6FAP, 0.5 g of pyridine, 40 g of γ-butyrolactone (GBL), and 30 g of toluene were added to the reaction vessel. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 34% was obtained.

[0151] Example 20 Preparation of Organosilicon Modified Polyimide A-18 (Siloxane Content 44%)

[0152] Using the same reaction vessel as in Example 1, 200 mmol of 6FDA, 50 mmol of 6FABP, 110 mmol of KF8010, 40 mmol of 6FAP, 0.5 g of pyridine, 40 g of γ-butyrolactone (GBL), and 30 g of toluene were added to the reaction vessel. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 34% was obtained.

[0153] Example 21 Preparation of Organosilicon Modified Polyimide A-19 (Siloxane Content 70%)

[0154] Using the same reaction vessel as in Example 1, 50 mmol of 6FDA, 50 mmol of sBPDA, 5 mmol of TFMB, 85 mmol of NH15D, 10 mmol of 6FAP, 0.5 g of pyridine, 50 g of methyl benzoate, and 150 g of γ-butyrolactone (GBL) were added to the reaction vessel. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 39% was obtained.

[0155] Example 22 Preparation of Organosilicon Modified Polyimide A-20 (Siloxane Content 48%)

[0156] Using the same reaction vessel as in Example 1, 100 mmol DSDA, 25 mmol p-6FAPB, 55 mmol NH15D, 20 mmol 6FAP, 0.5 g pyridine, 43.5 g diethylene glycol butyl methyl ether, and 101.5 g γ-butyrolactone (GBL) were added to the reaction vessel. The mixture was stirred at 20 rpm for 30 min under a nitrogen atmosphere, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 40% was obtained.

[0157] Example 23 Preparation of Organosilicon Modified Polyimide A-21 (Siloxane Content 69%)

[0158] Using the same reaction vessel as in Example 1, 100 mmol CBDA, 5 mmol PACM, 60 mmol NH15D, 35 mmol 6FAP, 0.5 g pyridine, 101 g γ-butyrolactone (GBL), and 43 g diethylene glycol butyl methyl ether were added to the reaction vessel. Under a nitrogen atmosphere, the mixture was stirred at 20 rpm for 30 min, then heated to 180 °C and stirred at 180 rpm for 4 h. During the reaction, the toluene-water azeotropic fraction was removed. By removing the reflux, a silicone-modified polyimide with a solid content of 40% was obtained.

[0159] Example 24 Preparation of silicone-modified polyimide resin composition film

[0160] The silicone-modified polyimides obtained in Examples 13-20 were mixed with epoxy resin and then subjected to vacuum degassing to obtain silicone-modified polyimide resin compositions. The degassing parameters were: vacuum degree -0.095 MPa, revolution speed 1500 rpm, rotation speed 1500 rpm, and vacuum degassing time 3 min. The silicone-modified polyimide resin composition was spread and coated onto a release liner using a doctor blade with a 300 μm gap to form a film. The film was then dried at 100°C for 30 min to remove residual solvent, and then the temperature was adjusted to 160°C and dried for another 90 min to induce a curing reaction. After drying, the film was peeled off from the release liner to obtain a silicone-modified polyimide resin composition film.

[0161] Example 25 Preparation of a composite film of organosilicon-modified polyimide resin composition

[0162] The silicone-modified polyimides obtained in Examples 1-18 and 21-22 were mixed with epoxy resin, phosphor, and alumina with a particle size distribution of 0.2-30 μm and an average particle size of 9.6 μm, respectively. Based on the silicone-modified polyimide, the phosphor content was 240% (i.e., 2.4 times the weight of the silicone-modified polyimide), with a (Ba,Sr,Ca)₂SiO₄:Eu to CaAlSiN₃:Eu addition ratio of 7:1. Based on the weight of the silicone-modified polyimide, the alumina content ratio was 560% (560 PHR) (i.e., 5.6 times the weight of the silicone-modified polyimide). The composite film was then prepared using the method described in Example 24.

[0163] Example 26 Preparation of a composite film of organosilicon-modified polyimide resin composition

[0164] The silicone-modified polyimide obtained in Example 19 was mixed with epoxy resin, alumina with a particle size distribution of 0.2–30 μm and an average particle size of 9.6 μm, and phosphor. Based on the silicone-modified polyimide, the phosphor content was 240% (i.e., 2.4 times the weight of the silicone-modified polyimide), with a (Ba,Sr,Ca)₂SiO₄:Eu to CaAlSiN₃:Eu addition ratio of 7:1. Based on the weight of the silicone-modified polyimide, the alumina content ratio was 760% (760 PHR).

[0165] (i.e., 7.6 times the weight of the organosilicon-modified polyimide), and then the composite film was prepared by the method described in Example 24.

[0166] Example 27 Preparation of a composite film of organosilicon-modified polyimide resin composition

[0167] The silicone-modified polyimide obtained in Example 20 was mixed with epoxy resin, alumina with a particle size distribution of 0.2–30 μm and an average particle size of 9.6 μm, and phosphor. Based on the silicone-modified polyimide, the phosphor content was 240% (i.e., 2.4 times the weight of the silicone-modified polyimide), with a (Ba,Sr,Ca)₂SiO₄:Eu to CaAlSiN₃:Eu addition ratio of 7:1. Based on the weight of the silicone-modified polyimide, the alumina content ratio was 960% (960 PHR) (i.e., 9.6 times the weight of the silicone-modified polyimide). The composite film was then prepared using the method described in Example 24.

[0168] Example 28 Preparation of a composite film of organosilicon-modified polyimide resin composition

[0169] The silicone-modified polyimide obtained in Example 23 was mixed with epoxy resin, heat dissipation particles, and phosphor. The heat dissipation particles included alumina and silica. The alumina had a particle size distribution of 0.2–30 μm and an average particle size of 9.6 μm; the silica had an average particle size of 2 μm. Based on the silicone-modified polyimide, the phosphor content was 600% (i.e., 6.0 times the weight of the silicone-modified polyimide), with the addition ratio of (Ba,Sr,Ca)₂SiO₄:Eu to CaAlSiN₃:Eu being 6:1. Based on the weight of the silicone-modified polyimide, the heat dissipation particle content was 400% (400 PHR) (i.e., 4.0 times the weight of the silicone-modified polyimide), with the addition ratio of alumina to silica being 1:1. Then, a composite film was prepared using the method described in Example 24.

[0170] Performance testing of silicone-modified polyimide resin composition film (film thickness 50 μm)

[0171] 1. Heat resistance: The glass transition temperature (Tg) was determined using a TMA-60 tester manufactured by Shimadzu Corporation. Test conditions: Load: 5 g; Heating rate: 10 °C / min; Measurement atmosphere: Nitrogen atmosphere; Nitrogen flow rate: 20 mL / min; Measurement temperature range: -40 to 300 °C.

[0172] 2. Chemical Resistance: At room temperature (25°C), cotton soaked in various chemicals was placed on the coating and left to stand for 30 minutes. The chemicals evaluated were ethanol, acetone, and dimethylformamide (DMF). The evaluation result is in the form of: ○: No abnormality;

[0173] △: Expansion and slight deformation; ×: Surface abnormality or dissolution.

[0174] 3. Light transmittance: The light transmittance was tested using a Shimadzu UV-1800 UV-Vis spectrophotometer. It measures the transmittance at a wavelength of 460nm based on the emission of the white LED. 460nm is the peak wavelength of InGaN used for blue excitation of white LEDs.

[0175] 4. Heat resistance and color change: The membrane used for the test is the same as the membrane used for the light transmittance test. The membrane is placed at 200℃ (in air atmosphere) for 24 hours, and the transmittance of the membrane at a wavelength of 460nm is measured after placement.

[0176] 5. Mechanical properties: The membrane width is 10 mm. The tensile properties of the membrane are tested according to ISO527-3:1995 standard, and the tensile speed is 10 mm / min.

[0177] Performance testing of silicone-modified imine resin composite film

[0178] 1. Thermal conductivity: The obtained film was cut into circles with a thickness of 300 μm and a diameter of 30 mm as test pieces. The thermal conductivity was measured using the DRL-Ⅲ thermal conductivity measuring device manufactured by Xiangke. Test conditions: hot electrode temperature: 90℃; cold electrode temperature: 20℃; load: 350N.

[0179] 2. Warping phenomenon: Place a 100um thick film with a length and width of 100mm into a 160℃ constant temperature chamber for 5 minutes. Remove it from the constant temperature chamber. At room temperature, the edge of the film will show warping. Warping height of less than 1mm is acceptable ○, 1mm to 5mm is pending △, and more than 5mm is unacceptable ×.

[0180] 3. Scanning electron microscopy (SEM) analysis: Gold was sputtered onto the surface of the composite film, and the surface morphology of the composite film was observed under a Tescan Vega 3 electron microscope.

[0181] 4. Mechanical properties: The membrane thickness is 50μm and the membrane width is 10mm. The tensile properties of the membrane are tested according to ISO527-3:1995 standard, and the tensile speed is 10mm / min.

[0182] The test results of the obtained silicone-modified polyimide resin composition films are shown in Tables 5 and 7, and the performance test results of the silicone-modified polyimide resin composition composite films are shown in Tables 6 and 8.

[0183] Table 5

[0184]

[0185]

[0186] Table 6

[0187]

[0188] Table 7

[0189]

[0190]

[0191] Table 8

[0192]

[0193]

[0194] The present invention has been disclosed above with reference to preferred embodiments. However, those skilled in the art should understand that these embodiments are merely illustrative of some implementations of the invention and should not be construed as limiting. It should be noted that all equivalent variations and substitutions to these embodiments, or reasonable combinations between embodiments, should be considered within the scope supported by this specification. Therefore, the scope of protection of the present invention should be determined by the scope defined in the appended claims.

Claims

1. An LED bulb lamp, comprising a lamp housing and a lamp holder connected to the lamp housing, wherein the lamp housing contains at least two conductive supports, a driving circuit, a cantilever, a core post, and an LED filament, the driving circuit being electrically connected to the conductive supports and the lamp holder, and the LED filament being connected to the core post through the conductive supports, characterized in that: The LED filament includes multiple LED chips and a light conversion layer coated on at least two sides of the LED chips. The light conversion layer includes a top layer and a base layer. A composite film made of organosilicon-modified polyimide resin was used as the substrate for LED filaments. The base layer is a composite film made of organosilicon-modified polyimide resin composition; The silicone-modified polyimide resin composition includes silicone-modified polyimide, a thermosetting agent, phosphor, and heat dissipation particles; The heat dissipation particles include particles with high light transmittance and particles with low light transmittance, and the weight ratio of the particles with high light transmittance to the particles with low light transmittance is 3 to 5:

1. The organosilicon-modified polyimide contains repeating units represented by the following general formula (Ⅰ): In general formula (Ⅰ), R is selected from methyl or phenyl, and n is 1 to 5; Ar 1 It is a tetravalent organic group having a benzene ring structure or an alicyclic hydrocarbon structure containing an active hydrogen functional group, wherein the active hydrogen functional group is any one of hydroxyl, amino, carboxyl or thiol group; Ar 2 It is a divalent organic group containing an active hydrogen functional group, wherein the active hydrogen functional group is any one of hydroxyl, amino, carboxyl or thiol group; The siloxane content of the organosilicon-modified polyimide is 30-70 wt%, and the siloxane content is the weight ratio of siloxane-type diamine to organosilicon-modified polyimide. The weight of organosilicon-modified polyimide is the sum of the weights of the diamine and dianhydride used in the synthesis of organosilicon-modified polyimide minus the weight of water generated during the synthesis process.

2. The LED bulb according to claim 1, characterized in that: The thermosetting agent is any one of epoxy resin, isocyanate, bismaleimide, and bisoxazoline compound.

3. The LED bulb according to claim 1, characterized in that: The phosphor is in the shape of spheres, plates, or needles.

4. The LED bulb according to claim 1, characterized in that: The amount of phosphor used is not less than 0.05 times and not more than 8 times the weight of the organosilicon-modified polyimide.

5. The LED bulb according to claim 1, characterized in that: The phosphor includes red phosphor and green phosphor, and the addition ratio of red phosphor to green phosphor is 1:5 to 8.

6. The LED bulb according to claim 1, characterized in that: The phosphor includes red phosphor and yellow phosphor, and the addition ratio of red phosphor to yellow phosphor is 1:5 to 8.

7. The LED bulb according to claim 1, characterized in that: Additives are added during the synthesis process of the silicone-modified polyimide resin composition. The additives include defoamers, leveling agents, or binders. The amount of the additives used is no more than 10% of the weight of the silicone-modified polyimide.

8. The LED bulb according to claim 1, characterized in that: The amount of phosphor used is greater than or equal to 0.05 times the weight of the organosilicon-modified polyimide.

9. The LED bulb according to claim 1, characterized in that: The heat dissipation particles are any one or a combination of one or more of the following: silicon dioxide, aluminum oxide, magnesium oxide, magnesium carbonate, aluminum nitride, boron nitride, and diamond.

10. The LED bulb according to claim 1, characterized in that: The organosilicon-modified polyimide includes fluorinated aromatic organosilicon-modified polyimide and aliphatic organosilicon-modified polyimide.

11. The LED bulb according to claim 1, characterized in that: The Ar in the organosilicon-modified polyimide 1 From dianhydrides, the Ar 2 It comes from diamine.

12. The LED bulb according to claim 1, characterized in that: The average particle size of the heat dissipation particles is 1 / 5 to 2 / 5 times the thickness of the substrate.

13. The LED bulb according to claim 1, characterized in that: The substrate includes an upper surface and a lower surface opposite to the upper surface. The upper surface of the substrate includes a first region and a second region. The second region includes pores. The surface roughness of the first region is less than that of the second region.

14. The LED bulb according to claim 8, characterized in that: The lower surface of the substrate includes a third region, the surface roughness of which is greater than that of the first region.

15. The LED bulb according to claim 1, characterized in that: The composite film of the organosilicon-modified polyimide resin composition has an elongation at break greater than 0.5% and an elastic modulus greater than 2.0 GPa.

16. The LED bulb according to claim 1, characterized in that: The refractive index of the silicone-modified polyimide resin composite film is 1.4 to 1.

7.

17. The LED bulb according to claim 1, characterized in that: The silicone-modified polyimide resin composite film has pores that scatter the light emitted by the LED chip.

18. The LED bulb according to claim 17, characterized in that: The volume ratio of the foam cells to the composite film of the organosilicon-modified polyimide resin composition is 5-20%.

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