A smoke-suppressing resin composition, a smoke-suppressing type covering film, and a method for preparing and using the same

Abstract

This invention provides a smoke-suppressing resin composition, a smoke-suppressing cover film, its preparation method, and its application. The smoke-suppressing resin composition, by solid weight, comprises the following components: 20-50 parts of silicone-modified soluble polyimide resin; 20-50 parts of silicone resin; 2-10 parts of curing agent; and 5-40 parts of filler. The silicone resin molecule contains hydroxyl groups derived from silanol groups at its terminal ends. The smoke-suppressing resin composition provided by this invention uses silicone-modified soluble polyimide resin and silicone resin as the main materials. It has good heat resistance and a high heteroatom content, effectively suppressing smoke generation during thermal decomposition. The addition of filler further enhances the smoke-suppressing effect. Furthermore, after MOT150 treatment, the visible light transmittance retention rate reaches over 80%. The cover film made from this smoke-suppressing resin composition can significantly improve product safety and user experience.

Description

Technical Field

[0001] This invention belongs to the field of covering film technology, and relates to a smoke-suppressing resin composition, a smoke-suppressing covering film, its preparation method and application. Background Technology

[0002] Currently, most mainstream cover film materials have achieved flame retardant properties. Flame retardant properties are used to measure the ability of a material to self-extinguish quickly after being ignited. The evaluation criteria include burning speed, duration, anti-dripping properties, and whether the drips continue to burn. Even the highest flame retardant level, UL V-0, will produce a lot of black smoke in the early stages of combustion and during the extinguishing process. This is very bad for the health and experience of users in certain situations, which has not been considered in the design of cover films in the past.

[0003] CN112625526A discloses a gradient-type heat-insulating and fire-retardant coating and its preparation method. Although this invention uses a modified polyimide resin with good heat resistance, it also adds a polyolefin resin with poor heat resistance and does not include smoke suppression design, resulting in an unsatisfactory smoke suppression effect.

[0004] CN115353744A discloses a halogen-free, low-smoke, flame-retardant polyolefin insulation material for nuclear-grade cables and its preparation method. Although this invention uses a high-entropy rare-earth zirconate-modified polyimide-siloxane block copolymer with good heat resistance, it also adds a polyolefin resin with poor heat resistance and does not design for smoke suppression performance, resulting in an unsatisfactory smoke suppression effect.

[0005] In addition to smoke suppression performance, the cover film also requires transparency, especially the ability to effectively maintain its transparency after heat treatment, in order to ensure a better user experience.

[0006] Therefore, it is desirable in the art to develop a smoke-suppressing resin composition, from which a smoke-suppressing covering film is prepared not only has a good smoke-suppressing effect but also good transparency. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a smoke-suppressing resin composition, a smoke-suppressing covering film, a method for preparing the same, and its application.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a smoke-suppressing resin composition, wherein the smoke-suppressing resin composition comprises, by weight parts of solids, the following components:

[0010]

[0011] The molecular ends of the organosilicon resin contain hydroxyl groups derived from silanol groups.

[0012] The smoke-suppressing resin composition provided by this invention uses silicone-modified soluble polyimide resin and silicone resin as the main materials. It has good heat resistance and high heteroatom content. When heated and decomposed, it can effectively inhibit the generation of smoke. At the same time, the addition of fillers can further enhance the smoke-suppressing effect. After treatment with MOT150 (198°C, 240h), the visible light transmittance retention rate reaches more than 80%. The covering film made from this smoke-suppressing resin composition can greatly improve product safety and user experience.

[0013] The silicone resin in this invention has a high heteroatom content and excellent smoke suppression performance, but its toughness after curing is poor, making it unsuitable for the field of cover films. Polyimide resin has good heat resistance, but its processability is poor and its compatibility with silicone resin is poor. This invention obtains silicone-modified soluble polyimide resin through silicone modification, which has the following advantages: good processability, allowing the use of traditional cover film processing technology; good compatibility with silicone resin, which can avoid phase separation, reduce light scattering in the resin composition, and give the smoke suppression resin composition high transparency, while the mixed material has good film-forming properties.

[0014] In this invention, the organosilicon resin molecule ends with hydroxyl groups derived from silanol groups. These silanol groups are highly reactive and can undergo cross-linking reactions with the curing agent to form stable chemical bonds, thereby forming a dense and stable interpenetrating cross-linked network structure. This increases the visible light transmittance retention rate of the smoke-suppressing resin composition after heat treatment and improves the peel strength of the smoke-suppressing resin composition.

[0015] In this invention, since the organosilicon-modified soluble polyimide resin and organosilicon resin still contain a small amount of aliphatic hydrocarbon segments, they may still form a small amount of smoke when heated and decomposed. Based on this, this invention introduces specific fillers to achieve a complete smoke suppression effect.

[0016] In this invention, the amount of organosilicon-modified soluble polyimide resin in the smoke-suppressing resin composition, based on parts by weight, can be, for example, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0017] In this invention, the amount of silicone resin used in the smoke-suppressing resin composition, by weight, can be, for example, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0018] In this invention, the amount of curing agent in the smoke-suppressing resin composition, based on the weight parts, can be, for example, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0019] In this invention, the amount of filler in the smoke-suppressing resin composition, by weight, can be, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0020] Preferably, the organosilicon-modified soluble polyimide resin is obtained by polymerizing a tetracarboxylic anhydride compound and a diamine compound, wherein at least one of the tetracarboxylic anhydride compound and the diamine compound contains silicon.

[0021] Preferably, the tetracarboxylic anhydride compounds include any one or a combination of at least two of the following: 9,9-bis(3,4-dicarboxyphenyl)fluorenyl dianhydride, bis(3,4-phenylcarboxylic anhydride)dimethylsilane (SIDA), phenyltetracarboxylic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (s-BTDA), 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride (a-ODPA), and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]malonium (BPADA).

[0022] Preferably, the diamine compounds include 1,3-bis-(2-aminoethylaminomethyl)tetramethyldisilane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, fluorene-2,5-ethylenediamine, 9,9'-spirobis[9H-fluorene]-2,2'-diamine, p-phenylenediamine (p-PDA), m-phenylenediamine (m-PDA), 4,4'-diaminodiphenyl ether (4,4'-ODA), 3,4'-diaminodiphenyl ether (3,4'-ODA), and 4,4'-diaminobiphenyl- The combination of any one or at least two of the following: 2,2'-dicarboxylic acid, 4,4'-diaminodiphenylmethane (4,4'-MDA), 4,4'-bis(4-aminophenoxy)biphenyl (4,4'-BAPB), 4,4'-diaminophenyl sulfone (4,4'-DDS), 3,5-diaminobenzoic acid, 4,4'-diaminobenzoylaniline (4,4'-DABA), 2-(4-aminophenyl)-5-aminobenzoxazole, bis(3-amino-4-hydroxyphenyl) sulfone, and 4,4'-diaminobenzophenone.

[0023] Preferably, the molar ratio of the diamine compound to the tetracarboxylic anhydride compound is 1:(1.0 to 1.3), for example, it can be 1:1.0, 1:1.05, 1:1.1, 1:1.15, 1:1.2, 1:1.25, 1:1.3, etc., and specific ratios between the above ratios are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0024] Preferably, the weight-average molecular weight of the organosilicon-modified soluble polyimide resin is 20,000 to 50,000, for example, it can be 20,000, 22,000, 24,000, 26,000, 28,000, 30,000, 32,000, 34,000, 36,000, 38,000, 40,000, 42,000, 44,000, 46,000, 48,000, 50,000, etc., as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0025] For example, the weight-average molecular weight can be determined by gel permeation chromatography (GPC) based on polystyrene calibration, according to GB / T 21863-2008.

[0026] Preferably, the silicone resin comprises R 1 SiO 3 / 2 The silsesquioxane unit is represented by R. 1 It refers to alkyl or phenyl groups with 1 to 15 carbon atoms.

[0027] As a result of R 1Alkyl groups representing 1 to 15 carbon atoms include, for example, straight-chain alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, and n-decyl; branched-chain alkyl groups such as isopropyl, isobutyl, isopentyl, isohexyl, and isodel; and cyclic alkyl groups such as cyclohexyl. Regarding R... 1 The phenyl group and the aforementioned cyclohexyl group, etc., may have at least one hydrogen atom on each ring replaced by an alkyl group having 1 to 15 carbon atoms.

[0028] By R 1 SiO 3 / 2 The silsesquioxane unit can be further subdivided into T1 structures [R] 1 O-Si(R 1 (OR) 1 )-O-]、T2 structure[-(R 1 )Si(OR 1 (O-)-O-] and T3 structure [-(R 1 [Si(O-)2-O-]. This invention does not particularly limit the ratio of T1, T2, and T3 structures; the ratio is typically around T1:T2:T3 = 0-5:10-40:90-60 using a molar ratio meter.

[0029] Preferably, the content of the hydroxyl groups derived from the silanol group is 1 to 10% by weight relative to the total weight of the silicone resin, for example, it can be 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight or 9% by weight, etc.

[0030] Preferably, the softening point of the silicone resin is 40-150°C, for example, it can be 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc., as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0031] For example, the softening point of silicone resin can be determined under the conditions specified in JIS K 5903.

[0032] In this invention, the silicone resin can be manufactured using various known methods, such as by hydrolysis and condensation of trialkoxysilane, or by commercially available products, such as Shin-Etsu Chemical Co., Ltd.'s KR-220L and KR-220LP, Momentive Advanced Materials Japan Co., Ltd.'s YR3370, Dow Corning's Z-6018, and Haiyandi New Materials Co., Ltd.'s YDSR1002.

[0033] Preferably, the curing agent comprises any one or a combination of at least two of the following: 4,4'-diaminodiphenylmethane epoxy resin, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, 2,6-diglycidyl-phenylglycidyl ether, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetra(epoxyethylenemethyl)-1,3-phenylenediamine.

[0034] In this invention, the curing agent can crosslink with the organosilicon-modified soluble polyimide resin to increase the crosslinking density of the system, and the resin composition has good heat resistance.

[0035] Preferably, the packing material is a porous packing material.

[0036] Preferably, the filler comprises any one or a combination of at least two of magnesium oxide, alumina, silicate, and molecular sieve. These fillers are porous and possess adsorption properties.

[0037] Preferably, the median particle size (D50) of the filler is 0.5 to 5 μm, for example, it can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, etc., as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0038] In this invention, the particle size was obtained using an MS3000 Malvern laser particle size analyzer.

[0039] In a second aspect, the present invention provides a smoke-suppressing cover film, the smoke-suppressing cover film comprising a base film and a smoke-suppressing adhesive layer disposed on the base film, the smoke-suppressing adhesive layer comprising the smoke-suppressing resin composition as described in the first aspect.

[0040] Preferably, the base film comprises any one of polyethylene terephthalate base film, polyethylene naphthalate base film, polyimide base film, polytetrafluoroethylene base film, polyethersulfone base film, polyphenylene sulfide base film, or polybenzimidazole base film.

[0041] Preferably, the thickness of the base film is 5 to 50 μm, for example, it can be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc., as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0042] Preferably, the thickness of the smoke-suppressing adhesive layer is 5–200 μm, for example, it can be 5 μm, 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, etc., as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0043] Thirdly, the present invention provides a method for preparing a smoke-suppressing covering film as described in the second aspect, the method comprising the following steps:

[0044] (1) Mix the silicone-modified soluble polyimide resin, silicone resin, curing agent, filler and solvent to obtain a mixed adhesive solution;

[0045] (2) The mixed adhesive solution is applied to one side of the base film and dried to obtain the smoke-suppressing cover film.

[0046] The present invention does not particularly limit the solvent mentioned in step (1). For example, it can be toluene, N,N-dimethylformamide (DMF), etc.

[0047] Preferably, the solid content of the mixed adhesive is 10-40%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc., and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0048] Fourthly, the present invention provides an application of the smoke-suppressing cover film as described in the second aspect in FPC (Flexible Printed Circuit).

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] The smoke-suppressing resin composition provided by this invention uses organosilicon-modified soluble polyimide resin and organosilicon resin as the main materials. It has good heat resistance and high heteroatom content. When heated and decomposed, it can effectively suppress the generation of smoke. At the same time, the addition of fillers can further enhance the smoke-suppressing effect. After treatment with MOT150, the visible light transmittance retention rate reaches more than 80%. The covering film made from this smoke-suppressing resin composition can greatly improve product safety and user experience. Detailed Implementation

[0051] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0052] Preparation Example 1

[0053] This preparation example provides a silicone-modified soluble polyimide resin, the preparation method of which includes the following steps:

[0054] To a three-necked flask equipped with a magnetic stirrer, a water separator, and a nitrogen inlet tube, add 24.9 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 5.1 g of 3,5-diaminobenzoic acid, 44.0 g of 3,4'-diaminodiphenyl ether (3,4'-ODA), and 836 g of DMF solvent, and stir until completely dissolved; then add 76.4 g of 9,9-bis(3,4'-ODA). 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride (a-ODPA) and 58.9 g of 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride were mixed and stirred for 20 h to prepare a precursor solution. Then, 200 g of xylene was added, stirred evenly, and heated to 135 °C for reflux to remove water. After 5 h, an organosilicon-modified soluble polyimide resin solution (denoted as organosilicon-modified soluble polyimide resin solution A) with a solid content of 20% was prepared.

[0055] Preparation Example 2

[0056] This preparation example provides a silicone-modified soluble polyimide resin, the preparation method of which includes the following steps:

[0057] 57.7 g of 9,9'-spirobis[9H-fluorene]-2,2'-diamine, 45.4 g of 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, and 620 g of DMF solvent were added to a three-necked flask equipped with a magnetic stirrer, a water separator, and a nitrogen inlet tube, and stirred until completely dissolved. Then, 63.7 g of bis(3,4-phthalic anhydride)dimethylsilane (SIDA) and 98.9 g of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]malonium (BPADA) were added, and the mixture was stirred for 20 h to prepare a precursor solution. 200 g of xylene was then added, and the mixture was stirred until homogeneous. The mixture was then heated to 135 °C and refluxed to separate water. After 5 h, an organosilicon-modified soluble polyimide resin solution (denoted as organosilicon-modified soluble polyimide resin solution B) with a solid content of 30% was prepared.

[0058] Comparative Preparation Example 1

[0059] This comparative preparation example provides a non-silicone soluble polyimide resin, the preparation method of which includes the following steps:

[0060] 57.7 g of 9,9'-spirodi[9H-fluorene]-2,2'-diamine, 45.4 g of 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, and 952 g of DMF solvent were added to a three-necked flask equipped with a magnetic stirrer, a water separator, and a nitrogen inlet tube, and stirred until completely dissolved. Then, 76.4 g of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride and 58.9 g of 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride (a-ODPA) were added, and the mixture was stirred for 20 h to prepare a precursor solution. 200 g of xylene was then added, and the mixture was stirred until homogeneous. The mixture was then heated to 135 °C and refluxed to separate water. After 5 h, a non-silicone soluble polyimide resin solution (denoted as non-silicone soluble polyimide resin solution C) with a solid content of 20% was obtained.

[0061] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this invention are as follows:

[0062] 1. Organosilicon-modified soluble polyimide resin

[0063] Organosilicon-modified soluble polyimide resin solution A: provided in Preparation Example 1;

[0064] Organosilicon-modified soluble polyimide resin solution B: provided in preparation example 2.

[0065] 2. Non-silicone soluble polyimide resin

[0066] Non-silicone soluble polyimide resin solution C: Provided in Comparative Preparation Example 1.

[0067] 3. Organosilicon resin

[0068] Organosilicon resin 1: Trade name "KR220L", Shin-Etsu Chemical Industry Co., Ltd., R 1 It is methyl, with a hydroxyl content of 3% by weight derived from the silanol group, and a softening point of 67°C;

[0069] Organosilicon resin 2: Trade name "Z-6018", Dow Corning, R 1 It consists of phenyl and n-propyl groups, with 6% by weight of hydroxyl groups derived from silanol groups, and a softening point of 40°C.

[0070] Organosilicon resin 3: Trade name "SILRES MK", Wacker Chemie GmbH, Germany, R 1 It is methyl, with 0% by weight of hydroxyl groups derived from silanol groups, and a softening point of 45°C;

[0071] Organosilicon resin 4: The structure is as follows, with 0% by weight hydroxyl content derived from silanol groups.

[0072]

[0073] 4. Hardener

[0074] 4,4'-Diaminodiphenylmethane epoxy resin: trade name "jER 604", Mitsubishi Chemical Corporation;

[0075] 1,3-Bis(N,N-diglycidylaminomethyl)cyclohexane: Trade name "TETRAD-C", Mitsubishi Chemical Corporation.

[0076] 5. Packing material

[0077] Magnesium oxide: Trade name "UC95S", UBE Corporation;

[0078] Alumina: Trade name "ALM43", UBE Corporation;

[0079] Spherical silica: Trade name "BQ029", Suzhou Jinyi New Material Technology Co., Ltd.

[0080] Example 1

[0081] This embodiment provides a smoke-suppressing cover film, which includes a polyimide-based film (12.5 μm thick) and a smoke-suppressing adhesive layer disposed on one side of the polyimide-based film;

[0082] The thickness of the smoke-suppressing adhesive layer, the specific selection of raw materials, and the amount (parts by weight) of the raw materials used are shown in Table 1.

[0083] The preparation method includes the following steps:

[0084] (1) Mix the soluble polyimide resin solution, silicone resin, curing agent, filler and solvent according to the formula in Table 1 to obtain a mixed adhesive with a solid content of 30%.

[0085] (2) The mixed adhesive solution is coated on one side of the polyimide-based film and dried to obtain the smoke-suppressing cover film.

[0086] Examples 2-5, Comparative Examples 1-6

[0087] The only difference from Example 1 is that the thickness of the smoke-suppressing adhesive layer, the specific selection and amount of raw materials used in preparation are different, as shown in Tables 1 and 2. The contents not shown in Tables 1 and 2 are considered to be the same as those in Example 1.

[0088] Table 1

[0089]

[0090] Table 2

[0091]

[0092]

[0093] The performance of the covering films provided in the above embodiments and comparative examples was tested using the following methods:

[0094] (1) Peel strength: According to IPC TM·650 Test Methods Manual 2.4.9, the 90° peel strength was tested;

[0095] (2) Solderability resistance: Tested according to IPC TM-650 Test Methods Manual 2.4.13;

[0096] (3) Flammability: Tested according to IPC-TM-650 Test Methods Manual 2.3.9;

[0097] (4) Smoke suppression: When testing flammability, visually observe the smoke generation; if obvious smoke is observed, it is judged as "smoke present"; if faint smoke is observed, it is judged as "smoke absent"; if no smoke is observed, it is judged as "smokeless".

[0098] (5) Visible light transmittance retention rate: After curing the cover film in an oven at 180℃ for 1h, the visible light transmittance in the receiving state and after MOT150 treatment (198℃, 240h) in the wavelength range of 360~760nm was tested using a spectrophotometer; the corresponding value was calculated according to the formula: visible light transmittance after MOT150 treatment / visible light transmittance in the receiving state × 100%.

[0099] The performance test results are shown in Table 3.

[0100] Table 3

[0101]

[0102]

[0103] As can be seen from Table 3, the covering films provided in Examples 1-5 of the present invention all have excellent flame retardancy (all reaching V-0) and good smoke suppression (low smoke or no smoke), as well as excellent peel strength (0.9-1.5 N / cm) and resistance to dip welding (all passing). They also have good transparency in the receiving state and after heat treatment (visible light transmittance in the receiving state: 72.7%-76.8%, visible light transmittance after MOT150 treatment: 59.85%-63.18%), and have a high visible light transmittance retention rate (80%-85%).

[0104] Compared to Example 1, the silicone resin in Comparative Example 1 lacks hydroxyl groups derived from silanol groups, preventing cross-linking with the curing agent and resulting in low cohesive strength of the adhesive layer, manifested as poor peel strength and poor solderability. While the silicone resin in Comparative Example 2 contains hydroxyl groups, these are not derived from silanol groups, making them less stable than silicon-oxygen bonds, thus negatively impacting light transmittance. The cover film provided in Comparative Example 3 does not use silicone resin, failing to effectively suppress smoke, and its light transmittance deteriorates after heat treatment. Comparative Example 4 lacks soluble polyimide resin, preventing film formation and making testing impossible. The cover film provided in Comparative Example 5, despite lacking fillers, still exhibits a small amount of smoke. Comparative Example 6 uses a non-silicone soluble polyimide resin, leading to phase separation in the adhesive layer and making it impossible to test the cover film's performance.

[0105] The applicant declares that the present invention is illustrated through the above embodiments to demonstrate the smoke-suppressing resin composition, smoke-suppressing covering film, preparation method, and application of the present invention. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A smoke-suppressing resin composition, characterized in that, The smoke-suppressing resin composition comprises the following components in parts by weight of solids: The molecular ends of the organosilicon resin contain hydroxyl groups derived from silanol groups.

2. The smoke-suppressing resin composition according to claim 1, characterized in that, The organosilicon-modified soluble polyimide resin is obtained by polymerizing a tetracarboxylic anhydride compound and a diamine compound, wherein at least one of the tetracarboxylic anhydride compound and the diamine compound contains silicon; Preferably, the tetracarboxylic anhydride compounds include any one or a combination of at least two of the following: 9,9-bis(3,4-dicarboxyphenyl)fluorenyl dianhydride, bis(3,4-phenylcarboxylic anhydride)dimethylsilane, phenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]malonium. Preferably, the diamine compound includes 1,3-bis-(2-aminoethylaminomethyl)tetramethyldisilane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, fluorene-2,5-ethylenediamine, 9,9'-spirobis[9H-fluorene]-2,2'-diamine, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl ether. The mixture comprises any one or a combination of at least two of the following: 2,2'-dicarboxylic acid, 4,4'-diaminodiphenylmethane, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diaminophenyl sulfone, 3,5-diaminobenzoic acid, 4,4'-diaminobenzoyl aniline, 2-(4-aminophenyl)-5-aminobenzoxazole, bis(3-amino-4-hydroxyphenyl) sulfone, and 4,4'-diaminobenzophenone.

3. The smoke-suppressing resin composition according to claim 2, characterized in that, The molar ratio of the diamine compound to the tetracarboxylic anhydride compound is 1:(1.0 to 1.3).

4. The smoke-suppressing resin composition according to any one of claims 1-3, characterized in that, The organosilicon-modified soluble polyimide resin has a weight-average molecular weight of 20,000 to 50,000.

5. The smoke-suppressing resin composition according to any one of claims 1-4, characterized in that, The silicone resin contains R 1 SiO 3 / 2 The silsesquioxane unit is represented by R. 1 Indicates alkyl or phenyl groups having 1 to 15 carbon atoms; Preferably, the content of the hydroxyl groups derived from the silanol group is 1 to 10% by weight relative to the total weight of the silicone resin; Preferably, the softening point of the silicone resin is 40–150°C.

6. The smoke-suppressing resin composition according to any one of claims 1-5, characterized in that, The curing agent comprises any one or a combination of at least two of the following: 4,4'-diaminodiphenylmethane epoxy resin, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, 2,6-diglycidyl-phenylglycidyl ether, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetra(epoxyethylenemethyl)-1,3-phenylenediamine. Preferably, the packing material is a porous packing material; Preferably, the filler comprises any one or a combination of at least two of magnesium oxide, alumina, silicate, and molecular sieve; Preferably, the median particle size (D50) of the filler is 0.5–5 μm.

7. A smoke-suppressing covering film, characterized in that, The smoke-suppressing cover film includes a base film and a smoke-suppressing adhesive layer disposed on the base film, wherein the smoke-suppressing adhesive layer includes the smoke-suppressing resin composition as described in any one of claims 1-6; The base film includes any one of polyethylene terephthalate base film, polyethylene naphthalate base film, polyimide base film, polytetrafluoroethylene base film, polyethersulfone base film, polyphenylene sulfide base film, or polybenzimidazole base film; Preferably, the thickness of the base film is 5–50 μm; Preferably, the thickness of the smoke-suppressing adhesive layer is 5–200 μm.

8. A method for preparing a smoke-suppressing covering film as described in claim 7, characterized in that, The preparation method includes the following steps: (1) Mix the silicone-modified soluble polyimide resin, silicone resin, curing agent, filler and solvent to obtain a mixed adhesive solution; (2) The mixed adhesive solution is applied to one side of the base film and dried to obtain the smoke-suppressing cover film.

9. The preparation method according to claim 8, characterized in that, The solid content of the mixed adhesive solution is 10-40%.

10. The application of the smoke-suppressing cover film as described in claim 7 in an FPC.

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