A dual-curing hot-pressing insulating film, FFC, and its preparation method and application

Abstract

The present invention provides a dual-curing hot-pressed insulating film, an FFC, and their preparation methods and applications. The dual-curing hot-pressed insulating film comprises a substrate layer and an adhesive layer that are adhered to each other; the raw materials for preparing the adhesive layer include: a photocurable polyester resin, an acrylic rubber, an epoxy resin, a photoinitiator, a curing agent, and a flame retardant. The FFC comprises a wire and the dual-curing hot-pressed insulating film covering both sides of the wire surface; the preparation method of the FFC comprises the following steps: placing a dual-curing hot-pressed insulating film on the upper surface and the lower surface of the wire respectively, performing roll pressing, and then performing photocuring and thermal curing in sequence to obtain the FFC. The dual-curing hot-pressed insulating film provided by the present invention has excellent properties, and the prepared FFC has good flame retardant properties, good high temperature and high humidity resistance properties, and good thermal shock properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of insulating films, and particularly relates to a dual-curing insulating film, a flexible flat cable, and a preparation method and application thereof. Background Art

[0002] FFC (i.e., Flexible Cable Tape, also known as flexible flat cable in Chinese) is made of an insulating hot-melt tape with PET as the base material and extremely thin and fine tinned flat copper wires. In the prior art, it is often hot-pressed by an automatic rolling composite machine, and has the advantages of being soft, bendable and foldable at will, thin in thickness, small in volume, simple in connection, convenient in disassembly, and easy to solve electromagnetic shielding (EMI), etc. At present, FFC is widely used in the connection between various printer print heads and motherboards, signal transmission and board-to-board connection of products such as plotters, scanners, copiers, audio systems, liquid crystal appliances, fax machines, and various disc players. In modern electrical equipment, FFC is almost everywhere. In addition to being able to be stably used on the above-mentioned 3C equipment and instruments, the rise of new energy vehicles has driven the development of high-reliability FFC products. Therefore, the research on FFC products is becoming more and more in-depth, and the reliability requirements are also getting higher and higher.

[0003] CN110283562A discloses a antimony-free flame-retardant hot-melt adhesive film for FFC wire and a preparation method thereof. The hot-melt adhesive film includes a PET insulating layer, a pre-coating layer, and a binder layer. The pre-coating layer is disposed between the PET insulating layer and the binder layer, and the thickness of the binder layer is less than that of the PET insulating layer; by weight percentage, the raw materials of the binder layer include: 25-35% saturated polyester resin A, 5-10% saturated polyester resin B, 5-10% saturated polyester resin C, 28-36% flame retardant a, 6-12% flame retardant b, 0.5-1% curing agent, and 12.5-14% balance; the saturated polyester resin C is a DOPO phosphorus-containing modified flame-retardant saturated polyester resin, and both the flame retardant a and the flame retardant b are antimony-free flame retardants. In this technical solution, by using antimony-free flame retardants, it is more environmentally friendly and can achieve the flame-retardant effect of VW-1. Although the hot-melt adhesive film provided by this technical solution has good flame retardancy, its long-term moisture and heat resistance and thermal shock resistance are poor, and it is not suitable for preparing automotive FFC products.

[0004] CN108586701A discloses an adhesive for a hot melt adhesive film, a preparation method thereof, and an application thereof in FFC wires. The adhesive, by mass fraction, comprises: 19% - 21% of saturated polyester resin A, 10% - 19% of saturated polyester resin B, 6% - 9% of saturated polyester resin C, 38% - 43% of a flame retardant, 5% - 7% of hexamethylene diisocyanate curing agent A, 1% - 3% of 2,4-diphenylmethane diisocyanate curing agent B, 1% - 3% of isophorone diisocyanate curing agent C, and the balance being a filler; the adhesive is prepared through a simple three-step process and is used for the hot melt adhesive film of FFC wires. The hot melt adhesive film sequentially comprises a PET hot melt adhesive film layer with a thickness of 19 - 50 μm from top to bottom, a pre-coating layer with a thickness of 1 - 3 μm, and a high heat resistance adhesive layer with a thickness of 20 - 50 μm. The hot melt adhesive film provided by this technical solution has a relatively complex structure and poor thermal shock performance, and is not suitable for preparing automotive FFC products.

[0005] In the prior art, the hot-pressing insulating adhesive film for FFC is usually a hot melt type. This material cannot meet long-term outdoor use, and due to the hydrolysis of the adhesive in a continuously high-temperature and high-humidity environment, its bonding strength decays rapidly and its service life is insufficient. Therefore, how to provide an insulating film for preparing automotive FFC with good flame retardant performance, good high-temperature and high-humidity resistance performance, and good thermal shock performance has become an urgent technical problem to be solved at present. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a dual-curing insulating film, a flexible flat cable, and a preparation method and application thereof. In the present invention, by designing the raw materials for preparing the adhesive layer in the dual-curing hot-pressing insulating film, and further through the use of a photocurable polyester resin, the prepared dual-curing hot-pressing insulating film has good flame retardant performance, good high-temperature and high-humidity resistance performance, and good thermal shock performance, and is suitable for preparing automotive FFC products.

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

[0008] In the first aspect, the present invention provides a dual-curing hot-pressing insulating film, which comprises a substrate layer and an adhesive layer that are adhered to each other;

[0009] The raw materials for preparing the adhesive layer comprise the following components in parts by weight: 100 parts of photocurable polyester resin, 3 - 20 parts of acrylic rubber, 5 - 30 parts of epoxy resin, 0.05 - 1 part of photoinitiator, 2 - 15 parts of curing agent, and 30 - 120 parts of flame retardant;

[0010] The raw materials for preparing the photocurable polyester resin comprise: dibasic acid monomers and / or anhydrides, diol monomers, oligo-polyols, and maleic anhydride.

[0011] In the present invention, by designing the raw materials for preparing the adhesive layer in the dual-curing hot-pressing insulating film, and further by using the photocurable polyester resin obtained with maleic anhydride as a modifier, the prepared dual-curing hot-pressing insulating film has a simple structure and has good flame retardancy, good high-temperature and high-humidity resistance, and good thermal shock resistance, can meet the requirements for long-term outdoor use, and is suitable for preparing automotive FFC products.

[0012] In the present invention, by using the photocurable polyester resin, when preparing the FFC subsequently, the dual-curing hot-pressing insulating film can be pre-cured under UV, so that the dual-curing hot-pressing insulating film has a certain thermal stability, and further when performing high-temperature thermal curing in the subsequent stage, the expansion and contraction of the FFC product are extremely small. Thus, the prepared FFC product has excellent heat resistance, high-temperature and high-humidity resistance, thermal shock resistance, and also has flame retardancy, and can meet long-term outdoor applications, such as electric vehicles, energy storage, etc.

[0013] In the present invention, by controlling the contents of epoxy resin and flame retardant within specific ranges respectively, the prepared dual-curing hot-pressing insulating film has good mechanical properties, good insulation properties, and good flame retardancy. If the dosage of epoxy resin is too much, the mechanical properties of the prepared dual-curing hot-pressing insulating film are poor; if the dosage of epoxy resin is too little, the heat resistance, flame retardancy, and hydrolysis resistance of the prepared dual-curing hot-pressing insulating film will all be adversely affected.

[0014] In the present invention, if the dosage of flame retardant is too much, the mechanical properties of the prepared dual-curing hot-pressing insulating film are poor; if the dosage of flame retardant is too little, the flame retardancy of the prepared dual-curing hot-pressing insulating film is poor.

[0015] In the present invention, in the raw materials for preparing the adhesive layer, the weight parts of the acrylic rubber can be 3 parts, 5 parts, 7 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc.

[0016] The weight parts of the epoxy resin can be 5 parts, 7 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 23 parts, 25 parts, 27 parts, 30 parts, etc.

[0017] The weight parts of the photoinitiator can be 0.05 parts, 0.07 parts, 0.08 parts, 0.1 parts, 0.2 parts, 0.5 parts, 0.6 parts, 0.8 parts, 0.9 parts, 1 part, etc.

[0018] The weight parts of the curing agent can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0019] The weight parts of the flame retardant can be 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts or 120 parts.

[0020] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved.

[0021] As a preferred technical solution of the present invention, the dibasic acid monomer is selected from any one or a combination of at least two of phthalic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, adipic acid, azelaic acid or sebacic acid;

[0022] Preferably, the acid anhydride is selected from any one or a combination of at least two of phthalic anhydride, succinic anhydride, adipic anhydride, azelaic anhydride or trimellitic anhydride;

[0023] Preferably, the diol is an alkylene diol with the number of carbon atoms ≥ 3;

[0024] Preferably, the diol is selected from any one or a combination of at least two of propylene glycol, polypropylene glycol, 2-methyl-1,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-2-ethyl-1,3-propanediol, 1,4-cyclohexanedimethanol or bisphenol A bis(2-hydroxyethyl) ether.

[0025] Preferably, the oligo polyol is selected from any one or a combination of at least two of polypropylene glycol, polytetrahydrofuran glycol, polycarbonate diol, polycaprolactone diol.

[0026] Preferably, the number average molecular weight of the oligo polyol is 500 - 3000, and can be, for example, 500, 700, 1000, 1200, 1500, 1800, 2000, 2200, 2500, 2700 or 3000, etc.

[0027] Preferably, the glass transition temperature (Tg) of the photocurable polyester resin is 0 - 40 °C (for example, it can be 0 °C, 5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, 35 °C or 40 °C, etc.), and more preferably 5 - 30 °C.

[0028] In the present invention, the test method for the glass transition temperature of the photocurable polyester resin is as follows: Weigh 10 mg of the photocurable polyester resin, and use a DSC differential scanning calorimeter (NETZSCH DSC 200F3) for testing. The scanning temperature range is -50 - 100 °C, and the heating rate is 20 K / min.

[0029] As a preferred technical solution of the present invention, the photocurable polyester resin is prepared by the following method, which comprises the following steps:

[0030] (1) In an atmosphere of protective gas, a dibasic acid and / or anhydride and a diol are placed in a reaction kettle for an esterification reaction to obtain an esterified product;

[0031] (2) After adding a polyol oligomer to the reaction system of step (1), mixing is carried out, and a saturated polyester resin is obtained through a polymerization reaction;

[0032] (3) Maleic anhydride is added to the reaction system of step (2) for a modification reaction to obtain the photocurable polyester resin.

[0033] In the present invention, through the reaction of maleic anhydride and the saturated polyester resin, carbon-carbon double bonds that can undergo photocuring are introduced into the polyester resin to obtain the photocurable polyester resin.

[0034] In the present invention, the protective gas atmospheres in steps (1) and (3) are each independently selected from nitrogen and argon.

[0035] As a preferred technical solution of the present invention, the molar ratio of the dibasic acid and / or anhydride to the diol is 1:(1.2 - 1.4), for example, it can be 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28, 1:1.3, 1:1.32, 1:1.34, 1:1.36, 1:1.38 or 1:1.4, etc.

[0036] Preferably, based on the mass percentage content of the esterified product being 100%, the mass percentage content of the polyol oligomer is 5% - 30%, for example, it can be 5%, 7%, 10%, 12%, 15%, 18%, 20%, 23%, 25%, 27% or 30%, etc.

[0037] In the present invention, the use of the polyol oligomer can improve the hydrolysis resistance. If the content of the polyol oligomer in the modified unsaturated polyester resin is too small, the hydrolysis resistance is insufficient; if the content of the polyol oligomer in the modified unsaturated polyester resin is too large, it is difficult to polymerize and graft, resulting in precipitation and incompatibility, and affecting the bonding strength.

[0038] Preferably, based on the molar percentage content of hydroxyl groups in the saturated polyester resin being 100%, the molar percentage content of maleic anhydride is 1% - 10% (for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc.), and more preferably 1% - 5%.

[0039] In the present invention, by controlling the content of maleic anhydride within a specific range, the dual-curing hot-pressing insulating film prepared has good high-temperature and high-humidity resistance and good thermal shock resistance. If the content of maleic anhydride is too small, there are too few unsaturated bonds in the photocurable polyester resin, and the mechanical properties of the prepared dual-curing hot-pressing insulating film are poor; if the content of maleic anhydride is too large, there are too many unsaturated bonds in the photocurable polyester resin, and the long-term heat resistance of the prepared dual-curing hot-pressing insulating film will deteriorate.

[0040] Preferably, the limiting viscosity IV of the saturated polyester resin is 0.3 to 1.0 dl / g (for example, it can be 0.3 dl / g, 0.4 dl / g, 0.5 dl / g, 0.6 dl / g, 0.7 dl / g, 0.8 dl / g, 0.9 dl / g or 1.0 dl / g, etc.), and more preferably 0.3 to 0.85 dl / g.

[0041] Preferably, the glass transition temperature (Tg) of the saturated polyester resin is 0 to 40 °C, for example, it can be 0 °C, 5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, 35 °C or 40 °C, etc.

[0042] As a preferred technical solution of the present invention, the temperature of the esterification reaction in step (1) is 150 to 200 °C.

[0043] Preferably, the time of the esterification reaction in step (1) is 4 to 6 h.

[0044] In the present invention, the esterification reaction in step (1) is carried out in a reaction kettle equipped with a stirrer, a cooling pipe and a thermometer.

[0045] Preferably, the time of the mixing in step (2) is 15 to 30 min, for example, it can be 15 min, 18 min, 20 min, 22 min, 25 min, 27 min or 30 min, etc.

[0046] Preferably, after the mixing in step (2), it further includes: evacuating the reaction kettle for 0.5 to 2 h (for example, it can be 0.5 h, 1 h, 1.5 h or 2 h, etc.), reducing the pressure in the reaction kettle to 200 to 800 Pa (for example, it can be 200 Pa, 300 Pa, 400 Pa, 500 Pa, 600 Pa, 700 Pa or 800 Pa, etc.), heating up to 230 to 280 °C (for example, it can be 230 °C, 240 °C, 250 °C, 260 °C, 270 °C or 280 °C, etc.), and continuing to evacuate to reduce the pressure in the reaction kettle to 10 to 50 Pa (for example, it can be 10 Pa, 20 Pa, 30 Pa, 40 Pa or 50 Pa, etc.).

[0047] Preferably, the temperature of the polymerization reaction in step (2) is 230 to 280 °C, for example, it can be 230 °C, 235 °C, 240 °C, 245 °C, 250 °C, 255 °C, 260 °C, 265 °C, 270 °C, 275 °C or 280 °C, etc.

[0048] Preferably, the time of the polymerization reaction in step (2) is 3 to 4 h, for example, it can be 3 h, 3.5 h or 4 h, etc.

[0049] Preferably, when maleic anhydride is added in step (3), the temperature of the reaction system is 150 to 170 °C, for example, it can be 150 °C, 152 °C, 155 °C, 157 °C, 160 °C, 161 °C, 164 °C, 168 °C or 170 °C, etc.

[0050] Preferably, the temperature of the modification reaction in step (3) is 150 to 170 °C, for example, it can be 150 °C, 152 °C, 155 °C, 157 °C, 160 °C, 161 °C, 164 °C, 168 °C or 170 °C, etc.

[0051] Preferably, the time of the modification reaction in step (3) is 40 to 80 min, for example, it can be 40 min, 50 min, 60 min, 70 min or 80 min, etc.

[0052] In the present invention, the preparation method of the photocurable polyester resin specifically comprises the following steps:

[0053] (1) In an atmosphere of protective gas, a dibasic acid and / or acid anhydride and a diol are placed in a reaction kettle equipped with a stirrer, a cooling pipe and a thermometer, and reacted at 150 to 200 °C for 3 to 5 h to obtain an esterified product; wherein, the molar ratio of the dibasic acid and / or acid anhydride to the diol is 1:(1.2 to 1.4);

[0054] (2) After adding a polyol oligomer to the reaction system of step (1), stirring for 15 to 30 min to mix evenly, then evacuating the reaction kettle, reducing the pressure in the reaction kettle to 200 to 800 Pa within 0.5 to 2 h, heating to 230 to 280 °C, continuing to evacuate, reducing the pressure in the reaction kettle to 10 to 50 Pa, and reacting at 230 to 280 °C for 3 to 4 h to obtain a saturated polyester resin; wherein, based on the mass percentage content of the esterified product being 100%, the mass percentage content of the polyol oligomer is 5% to 30%;

[0055] (3) Cool the reaction system in step (2) to 150 - 170 °C, add maleic anhydride thereto, and carry out a modification reaction at 150 - 170 °C for 40 - 80 min to obtain the photocurable polyester resin; based on the hydroxyl molar percentage content in the saturated polyester resin being 100%, the molar percentage content of the maleic anhydride is 1% - 10%, and more preferably 1% - 5%.

[0056] As a preferred technical solution of the present invention, the acrylic rubber is selected from any one or a combination of at least two of ethylene - acrylate rubber (AEM), acrylate rubber (ACM), or acrylic block copolymer (MAM).

[0057] It should be noted that the AEM refers to a polymer obtained by reacting ethylene and methyl acrylate as the main monomers (molar ratio ≥ 50%) and at least one monomer from acrylic acid, maleic acid (cis - butenedioic acid), itaconic acid (methylenebutanedioic acid), glycidyl methacrylate (GMA), and allyl glycidyl ether (AGE) (molar ratio < 50%); the ACM is a polymer obtained by reacting at least two monomers from butyl acrylate, ethyl acrylate, methyl acrylate, 2 - ethylhexyl acrylate, acrylonitrile, acrylic acid, maleic acid (cis - butenedioic acid), itaconic acid (methylenebutanedioic acid), glycidyl methacrylate (GMA), and allyl glycidyl ether (AGE); the MAM includes any one or a mixture of at least two of polymethyl methacrylate - polybutyl acrylate copolymer and polymethyl methacrylate - poly(butyl acrylate / 2 - ethylhexyl acrylate) copolymer.

[0058] Preferably, the epoxy resin is selected from any one or a combination of at least two of bisphenol A - type epoxy resin, bisphenol F - type epoxy resin, bisphenol S - type epoxy resin, phenolic - type epoxy resin, phenol - biphenyl - type epoxy resin, or dicyclopentadiene - phenol - type epoxy resin.

[0059] Preferably, the photoinitiator is selected from carbon - based compounds, peroxides, nitrogen - containing compounds, organic sulfides, halides, photoreductive dyes, and quinone - type photoinitiators, and more preferably quinone - type photoinitiators.

[0060] Preferably, the quinone - type photoinitiator includes benzoin ether - type photoinitiators.

[0061] Preferably, the curing agent is a blocked isocyanate curing agent.

[0062] It should be noted that the blocked isocyanate curing agent in the present invention can be purchased or obtained by an addition reaction of an isocyanate and a blocking agent.

[0063] Preferably, the isocyanate is selected from any one or a combination of at least two of aromatic isocyanates, aliphatic isocyanates, and alicyclic isocyanates.

[0064] Preferably, the aromatic isocyanate is selected from any one or a combination of at least two of toluene diisocyanate (TDI), toluene diisocyanate dimer, toluene diisocyanate trimer, 2,4-diphenylmethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate dimer, 2,4-diphenylmethane diisocyanate trimer, xylylene diisocyanate (XDI), xylylene diisocyanate dimer, or xylylene diisocyanate trimer.

[0065] Preferably, the aliphatic isocyanate is selected from any one or a combination of at least two of hexamethylene diisocyanate (HDI), hexamethylene diisocyanate dimer, or hexamethylene diisocyanate trimer.

[0066] Preferably, the alicyclic isocyanate is selected from any one or a combination of at least two of isophorone diisocyanate (IPDI), isophorone diisocyanate dimer, or isophorone diisocyanate trimer.

[0067] Preferably, the blocking agent is selected from any one or a combination of at least two of phenol, imidazole, polyether diol, ε-caprolactam, 1,2,4-triazole, or methyl ethyl ketoxime.

[0068] Preferably, the flame retardant is selected from any one or a combination of at least two of bromine (Br)-based flame retardants, phosphorus (P)-based flame retardants, phosphorus (P)-aluminum (Al)-based flame retardants, nitrogen (N)-based flame retardants, silicon (Si)-based flame retardants, metal hydroxide-based flame retardants, metal oxide flame retardants, or metal boride flame retardants, and more preferably any one or a combination of at least two of phosphorus (P)-based flame retardants, phosphorus (P)-aluminum (Al)-based flame retardants, and nitrogen (N)-based flame retardants.

[0069] As a preferred technical solution of the present invention, the raw materials for preparing the adhesive layer further include 0.1 to 1 part of a curing accelerator, for example, it can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, or 1 part, etc.

[0070] Preferably, the curing accelerator is selected from organic amine-based curing accelerators and / or metal salt-based curing accelerators.

[0071] Preferably, the raw materials for preparing the adhesive layer further include 0.1 to 2 parts of an antioxidant, for example, it can be 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, 1.2 part, 1.4 part, 1.6 part, 1.8 part, or 2 parts, etc.

[0072] Preferably, the antioxidant is selected from any one or a combination of at least two of aromatic amine antioxidants, hindered phenol antioxidants, phosphite antioxidants or thioester antioxidants, and more preferably a combination of at least two of aromatic amine antioxidants, hindered phenol antioxidants, phosphite antioxidants or thioester antioxidants.

[0073] Preferably, the raw materials for preparing the adhesive layer further include 0.1-2 parts of a dispersion aid, such as 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts or 2 parts, etc.

[0074] Preferably, the dispersion aid is selected from any one or a combination of at least two of titanate coupling agents, aluminate coupling agents, organosilane coupling agents, organic chromium complex coupling agents or borate coupling agents.

[0075] Second, the present invention provides a method for preparing a dual-curing hot-pressed insulating film as described in the first aspect, and the preparation method includes the following steps:

[0076] Mix the raw materials for preparing the adhesive layer with a solvent to obtain a mixed solution, and then coat it on one side surface of the substrate and dry it to obtain the dual-curing hot-pressed insulating film.

[0077] Preferably, the substrate is a corona-treated PET film (polyethylene terephthalate film).

[0078] It should be noted that the obtained mixed solution is coated on the corona-treated side of the substrate.

[0079] Preferably, the thickness of the substrate is 19-50 μm, such as 19 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm, etc.

[0080] Preferably, the specific drying method includes: drying at 70-90 °C (such as 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, etc.) for 2-5 min (such as 2 min, 3 min, 4 min or 5 min, etc.), and then heating to 110-130 °C (such as 110 °C, 112 °C, 115 °C, 117 °C, 120 °C, 121 °C, 124 °C, 128 °C or 130 °C, etc.) and drying for 2-5 min (such as 2 min, 3 min, 4 min or 5 min, etc.).

[0081] Preferably, the thickness of the adhesive layer of the dual-curing hot-pressing insulating film is 15-80 μm (for example, it can be 15 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm or 80 μm, etc.), and more preferably 20-60 μm.

[0082] In a third aspect, the present invention provides an FFC, which includes a wire and the dual-curing hot-pressing insulating film as described in the first aspect covering both sides of the wire surface.

[0083] It should be noted that in the present invention, there are no special restrictions on the number of wires in the flexible flat cable, and those skilled in the art can design according to actual usage requirements. At the same time, the present invention has no special restrictions on the length and height of the cross-section of the wire, and can be designed according to actual usage requirements. Exemplarily, but not limited to: the length of the cross-section of the wire is 1 mm and the height is 0.1 mm.

[0084] Preferably, the wire is a pure copper wire, a tinned copper wire or a nickel-plated copper wire.

[0085] Preferably, the line spacing between any two adjacent wires is 1-3 mm, for example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm, etc.

[0086] In a fourth aspect, the present invention provides a preparation method of the FFC as described in the third aspect, and the preparation method includes the following steps:

[0087] Place a dual-curing hot-pressing insulating film as described in the first aspect on the upper and lower surfaces of the wire respectively. After rolling, perform light curing and thermal curing in sequence to obtain the FFC;

[0088] Preferably, the temperature of the rolling is 160-200 °C, for example, it can be 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C, 195 °C or 200 °C, etc.

[0089] Preferably, the pressure of the rolling is 0.3-0.6 MPa, for example, it can be 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa or 0.6 MPa, etc.

[0090] Preferably, the time of the rolling is 2-3 s, for example, it can be 2 s or 3 s.

[0091] Preferably, the time of the light curing is 2-3 s, for example, it can be 2 s or 3 s.

[0092] Preferably, the light intensity of the light curing is 800-4000 mJ / cm 2, for example, it can be 800 mJ / cm 2 、1000 mJ / cm 2 、1500 mJ / cm 2 、2000 mJ / cm 2 、2500 mJ / cm 2 、3000 mJ / cm 2 、3500 mJ / cm 2 or 4000 mJ / cm 2 etc.

[0093] Preferably, the temperature of the thermal curing is 90 - 130 °C, for example, it can be 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, or 130 °C, etc.

[0094] Preferably, the time of the thermal curing is 1 - 3 h, for example, it can be 1 h, 1.5, 2 h, 2.5 h, or 3 h, etc.

[0095] The preparation method of the FFC in the present invention specifically includes the following steps:

[0096] Place a double - curing hot - press insulating film as described in the first aspect on the upper and lower surfaces of the wire respectively. Under the conditions of a temperature of 160 - 200 °C and a pressure of 0.3 - 0.6 MPa, roll - press for 2 - 3 s, then under the condition of a light intensity of 800 - 4000 mJ / cm, perform photo - curing for 2 - 3 s, and then bake at 90 - 130 °C for 1 - 3 h to complete the thermal curing, thus obtaining the FFC.

[0097] In the fifth aspect, the present invention provides an application of the FFC as described in the third aspect in the field of new energy vehicles.

[0098] Compared with the prior art, the present invention has the following beneficial effects:

[0099] (1) In the present invention, by designing the preparation raw materials of the adhesive layer in the double - curing hot - press insulating film, and further through the use of photo - curing polyester resin, the prepared double - curing hot - press insulating film has a simple structure, and has good flame - retardant performance, good high - temperature and high - humidity resistance performance, and good thermal shock performance, can meet the requirements of long - term outdoor use, and is suitable for preparing vehicle - used FFC products.

[0100] (2) The FFC prepared from the dual-curing hot-pressing insulating film provided by the present invention has excellent comprehensive performance. There are no blisters around the wires of the prepared FFC, no obvious glue overflow at the wire terminals, the initial peel strength is 114-130 gf / mm. After high-temperature and high-humidity testing, there are no blisters around the wires of the FFC, no glue opening at the wire edge, the peel strength is 100-117 gf / mm, the resistance value between adjacent lines > 500 MΩ. After thermal shock testing, there are no blisters around the wires of the FFC, no obvious glue overflow at the wire terminals, the peel strength is 95-125 gf / mm. After flame retardancy testing, its flame retardancy effect reaches VTM-0. Detailed implementation manners

[0101] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0102] The sources of some components in the examples and comparative examples are as follows:

[0103] Polycarbonate diol: number average molecular weight is 1000, Oxymer from Perstorp, Sweden TM M112;

[0104] Polytetrahydrofuran diol: number average molecular weight is 650, PTMG650 from Mitsubishi Chemical, Japan;

[0105] Polycaprolactone diol: number average molecular weight is 1000, Capa2161A from Perstorp, Sweden.

[0106] In the saturated polyester resin provided in the following preparation examples, the hydroxyl value is the milligrams of potassium hydroxide equivalent to the hydroxyl content in each gram of the sample, unit: mg KOH / g, and the test method refers to DIN 53 240-02; the acid value is the milligrams of potassium hydroxide required to neutralize the acidic substances in 1 g of the sample, unit: mg KOH / g, and the test method refers to DIN EN ISO 2114.

[0107] Preparation Example 1

[0108] This preparation example provides a photocurable polyester resin and its preparation method, and the preparation method is as follows:

[0109] (1) Under nitrogen protection, terephthalic acid (5 mol), isophthalic acid (2 mol), sebacic acid (3 mol), neopentyl glycol (6 mol), 1,6-hexanediol (6 mol) are placed in a stainless steel reaction kettle equipped with a stirrer, a cooling tube and a thermometer, and esterification reaction is carried out at 150-200 °C for 4 h to obtain an esterified product;

[0110] (2) After adding polycarbonate diol to the reaction system in step (1), stir for 20 min to mix evenly, then evacuate the reaction kettle for 1 h until the pressure in the reaction kettle drops to 400 - 650 Pa, continue to heat up to 250 °C, reduce the pressure in the reaction kettle to 10 - 40 Pa, and react at 250 °C for 3 h to obtain a saturated polyester resin with a hydroxyl value of 15 mg KOH / g and an acid value of 1.2 mg KOH / g; wherein, based on the mass percentage of the esterified product being 100%, the mass percentage of the polycarbonate diol is 10%;

[0111] (3) Cool the reaction system in step (2) to 160 °C, add maleic anhydride (2.52 g) thereto, and carry out a modification reaction at 160 °C for 60 min to obtain the photocurable polyester resin; based on the molar percentage of hydroxyl groups in the saturated polyester resin being 100%, the molar percentage of maleic anhydride is 4%.

[0112] Preparation Example 2

[0113] This preparation example provides a photocurable polyester resin and its preparation method, and the preparation method is as follows:

[0114] (1) Under nitrogen protection, put terephthalic acid (5 mol), succinic acid (2 mol), adipic acid (3 mol), 1,4 - butanediol (7 mol), and 1,6 - hexanediol (6 mol) into a stainless - steel reaction kettle equipped with a stirrer, a cooling pipe, and a thermometer, and carry out an esterification reaction at 150 - 200 °C for 5 h to obtain an esterified product;

[0115] (2) After adding polytetrahydrofuran diol to the reaction system in step (1), stir for 20 min to mix evenly, then evacuate the reaction kettle for 1 h until the pressure in the reaction kettle drops to 400 - 650 Pa, continue to heat up to 250 °C, reduce the pressure in the reaction kettle to 10 - 40 Pa, and react at 250 °C for 4 h to obtain a saturated polyester resin with a hydroxyl value of 20 mg KOH / g and an acid value of 0.8 mg KOH / g; wherein, based on the mass percentage of the esterified product being 100%, the mass percentage of the polytetrahydrofuran diol is 5%;

[0116] (3) Cool the reaction system in step (2) to 160 °C, add maleic anhydride (1.68 g) thereto, and carry out a modification reaction at 160 °C for 60 min to obtain the photocurable polyester resin; based on the molar percentage of hydroxyl groups in the saturated polyester resin being 100%, the molar percentage of maleic anhydride is 2%.

[0117] Preparation Example 3

[0118] This preparation example provides a photocurable polyester resin and its preparation method, and the preparation method is as follows:

[0119] (1) Under nitrogen protection, phthalic acid (5 mol), azelaic acid (2 mol), terephthalic acid (3 mol), 1,5-pentanediol (7 mol), and 1,3-propanediol (7 mol) were placed in a stainless-steel reaction kettle equipped with a stirrer, a condenser, and a thermometer, and an esterification reaction was carried out at 150 - 200 °C for 5 h to obtain an esterified product.

[0120] (2) After adding polycaprolactone diol to the reaction system of step (1), stirring was carried out for 20 min to mix evenly, and then the reaction kettle was evacuated for 1 h until the pressure in the reaction kettle dropped to 400 - 650 Pa. Then, the temperature was further raised to 260 °C, and the pressure in the reaction kettle was reduced to 10 - 40 Pa. The reaction was carried out at 260 °C for 3 h to obtain a saturated polyester resin with a hydroxyl value of 14 mg KOH / g and an acid value of 0.65 mg KOH / g. Among them, based on the mass percentage of the esterified product being 100%, the mass percentage of the polycaprolactone diol was 10%.

[0121] (3) The reaction system of step (2) was cooled to 160 °C, and maleic anhydride (1.77 g) was added thereto. A modification reaction was carried out at 160 °C for 60 min to obtain the photocurable polyester resin. Based on the molar percentage of hydroxyl groups in the saturated polyester resin being 100%, the molar percentage of maleic anhydride was 3%.

[0122] Preparation Example 4

[0123] This preparation example provides a photocurable polyester resin and its preparation method. The difference from Example 1 is only that in step (2), based on the mass percentage of the esterified product being 100%, the mass percentage of the polycarbonate diol is 3%, and the others are the same as in Preparation Example 1.

[0124] Preparation Example 5

[0125] This preparation example provides a photocurable polyester resin and its preparation method. The difference from Example 1 is only that in step (2), based on the mass percentage of the esterified product being 100%, the mass percentage of the polycarbonate diol is 35%, and the others are the same as in Preparation Example 1.

[0126] Preparation Example 6

[0127] This preparation example provides a photocurable polyester resin and its preparation method. The difference from Example 1 is only that in step (3), the mass of maleic anhydride added is 0.3 g. Based on the molar percentage of hydroxyl groups in the saturated polyester resin being 100%, the molar percentage of maleic anhydride is 0.5%, and the others are the same as in Preparation Example 1.

[0128] Preparation Example 7

[0129] This Preparation Example provides a photocurable polyester resin and a preparation method thereof. The difference from Preparation Example 1 is only that in step (3), the mass of maleic anhydride added is 7.6 g, and based on the hydroxyl molar percentage content in the saturated polyester resin being 100%, the molar percentage content of maleic anhydride is 12%, and the others are the same as in Preparation Example 1.

[0130] The descriptions and sources of some components used in the following Examples and Comparative Examples are shown in Table 1 below:

[0131] Table 1

[0132]

[0133]

[0134] Examples 1 - 7

[0135] Examples 1 - 7 respectively provide a dual-curing hot-pressing insulating film and a preparation method thereof. The dual-curing hot-pressing insulating film includes a substrate layer and an adhesive layer that are adhered together;

[0136] The preparation raw materials of the adhesive layer are shown in Table 2 respectively, where the contents of each component in Table 2 are all in parts by weight.

[0137] The preparation method of the adhesive layer is as follows:

[0138] Mix the raw material components of the adhesive layer evenly to obtain a mixed solution, then coat it on the corona-treated side surface of the corona-treated PET film, dry it at 80 °C for 3 min, and then raise the temperature to 120 °C and dry it for 3 min to obtain a dual-curing hot-pressing insulating film with a thickness of 50 μm.

[0139] Table 2

[0140]

[0141]

[0142] Examples 8 - 11

[0143] Examples 8 - 11 respectively provide a dual - curing hot - pressing insulating film and a preparation method thereof. The difference from Example 1 is that the photo - curing polymerization resin R1 used in Example 1 is changed to the photo - curing polymerization resin R4 provided in Preparation Example 4 (Example 8), the photo - curing polymerization resin R1 used in Example 1 is changed to the photo - curing polymerization resin R5 provided in Preparation Example 4 (Example 9), the photo - curing polymerization resin R1 used in Example 1 is changed to the photo - curing polymerization resin R6 provided in Preparation Example 4 (Example 10), and the photo - curing polymerization resin R1 used in Example 1 is changed to the photo - curing polymerization resin R7 provided in Preparation Example 4 (Example 11);

[0144] Other conditions are the same as those in Example 1.

[0145] Comparative Examples 1 - 2

[0146] Comparative Examples 1 - 2 respectively provide a dual - curing hot - pressing insulating film and a preparation method thereof. The difference from Example 3 is that 12 parts by weight of NPES901 in the raw materials for preparing the binder layer in Example 3 is successively replaced with 3 parts by weight of NPES901 (Comparative Example 1) and 40 parts by weight of NPES901 (Comparative Example 2);

[0147] Other conditions are the same as those in Example 3.

[0148] Comparative Example 3

[0149] Comparative Example 3 provides a dual - curing hot - pressing insulating film and a preparation method thereof. The difference from Example 3 is that 6 parts by weight of M22N in the raw materials for preparing the binder layer in Example 3 is replaced with 8 parts by weight, 12 parts by weight of NPES901 is replaced with 15 parts by weight, and 0.1 part by weight of photo - initiator 651 is replaced with 0.02 part by weight of photo - initiator 651;

[0150] Other conditions are the same as those in Example 3.

[0151] Comparative Example 4

[0152] Comparative Example 4 provides a dual - curing hot - pressing insulating film and a preparation method thereof. The difference from Example 3 is that 6 parts by weight of M22N in the raw materials for preparing the binder layer in Example 3 is replaced with 8 parts by weight, 12 parts by weight of NPES901 is replaced with 15 parts by weight of NPES901, and 50 parts by weight of flame retardant OP935 is replaced with 140 parts by weight;

[0153] Other conditions are the same as those in Example 3.

[0154] Application Example 1

[0155] This application example provides an FFC and a preparation method thereof. The preparation method is as follows:

[0156] On the upper and lower surfaces of 8 pure copper wires with an online spacing of 2.0 mm, a double-curing hot-pressing insulating film provided in Example 1 was respectively placed. Under the conditions of a temperature of 180 °C and a pressure of 0.5 MPa, after roller pressing for 3 s, under the condition of a light intensity of 2000 mj / cm, light curing was carried out for 3 s, and then baking was carried out at 120 °C for 3 h to complete the thermal curing, and the FFC was obtained.

[0157] Application Example 2-11

[0158] Application Example 2-11 respectively provides an FFC and a preparation method thereof. The difference from Application Example 1 is that the double-curing hot-pressing insulating film provided in Example 1 is sequentially replaced with the double-curing hot-pressing insulating films provided in Examples 2-11, and other conditions are the same as those in Application Example 1.

[0159] Application Comparative Example 1-4

[0160] Application Comparative Example 1-4 respectively provides a flexible flat cable and a preparation method thereof. The difference from Application Example 1 is that the double-curing hot-pressing insulating film provided in Example 1 is sequentially replaced with the double-curing hot-pressing insulating films provided in Comparative Examples 1-4, and other conditions are the same as those in Application Example 1.

[0161] The performance of the double-curing hot-pressing insulating films provided in the above examples and comparative examples, and the FFCs provided in the application examples and application comparative examples was tested. The specific test methods are as follows:

[0162] Initial appearance and peel strength: Observe whether there are bubbles around the wires of the FFCs provided in the above application examples and application comparative examples, and whether there is obvious glue overflow at the wire terminals (upper). If the glue overflow > 0.3 mm, it is NG; if the glue overflow ≤ 0.3 mm, it is OK; the peel strength of the FFCs provided in the above application examples and application comparative examples was tested. The test conditions were: 180°, 100 mm / min;

[0163] Appearance and peel strength after high-temperature and high-humidity aging test: Put the FFCs provided in the above application examples and application comparative examples into a high-temperature and high-humidity environmental chamber for 1500 h, take them out and cool them to room temperature, observe whether there are bubbles around the wires and whether there is delamination at the wire edges. If there is, it is NG; if not, it is OK; refer to the above standard to test the peel strength of the FFCs provided in the application examples and application comparative examples. The test conditions were: 180°, 100 mm / min;

[0164] Inter-wire insulation impedance test: Apply a DC voltage of 500 V between two adjacent wires of the FFC after the above high-temperature and high-humidity aging test for 60 s, and test its resistance value;

[0165] Appearance and peel strength after thermal shock aging test: Put the FFCs provided in the above application examples and application comparative examples into a thermal shock environmental chamber for 1000 h, at -40 °C for (0.5 h) and 125 °C for (0.5 h), with the thermal cycle time within 2 min. After 1000 cycles, take them out and cool to room temperature. Observe whether there are bubbles around the wires and whether there is glue overflow at the wire terminals (upper part). If there is, it is NG; if not, it is OK. Test the peel strength of the FFCs provided in the application examples and application comparative examples with reference to the above standards. The test conditions are: 180°, 100 mm / min;

[0166] Flame retardancy: Make the dual-curing hot-pressing films provided in the above examples and comparative examples into test specimens of 50 mm × 200 mm. According to the classification of the flame retardancy grade of the film by UL-94, the highest flame retardancy grade is VTM-0, followed by VTM-1, VTM-2, HB, etc.

[0167] Comprehensive evaluation: Evaluate based on the data of the initial appearance and peel strength, the appearance and peel strength after high-temperature and high-humidity aging test, the inter-line insulation impedance test, the appearance and peel strength after thermal shock aging test, and the flame retardancy;

[0168] "◎" represents excellent performance, "○" represents qualified performance, "△" represents general performance, and "×" represents poor performance.

[0169] "◎" represents excellent performance: The initial appearance is OK, the initial peel force ≥ 120 gf / mm, the appearance after high-temperature and high-humidity is OK, the peel force ≥ 100 gf / mm, the appearance after thermal shock is OK, the peel force ≥ 100 gf / mm, and the flame retardancy is VTM-0 grade;

[0170] "○" represents qualified performance: The initial appearance is OK, the initial peel force > 110 gf / mm, the appearance after high-temperature and high-humidity is OK, the peel force ≥ 90 gf / mm, the appearance after thermal shock is OK, the peel force ≥ 100 gf / mm, and the flame retardancy is VTM-1 grade or above;

[0171] "△" represents general performance: The initial appearance is OK, the initial peel force > 110 gf / mm, the appearance after high-temperature and high-humidity is OK, the peel force ≥ 80 gf / mm, the appearance after thermal shock is OK, the peel force ≥ 90 gf / mm, and the flame retardancy is VTM-2 grade or above;

[0172] "×" represents poor performance: The initial appearance is NG, or the initial peel force < 100 gf / mm, or the appearance after high-temperature and high-humidity is NG, or the peel force < 80 gf / mm, the appearance after thermal shock is NG, or the peel force < 90 gf / mm, or the flame retardancy is VTM-2 grade, or the insulation impedance < 500 MΩ;

[0173] The performance test data of the dual-curing hot-pressing insulating film provided by the above embodiments and comparative examples, and the FFC provided by the application examples and application comparative examples are shown in Table 3 below:

[0174] Table 3

[0175]

[0176]

[0177] As can be seen from the content of Table 3, in the present invention, by designing the preparation raw materials of the adhesive layer in the dual-curing hot-pressing insulating film, and further by using a photocurable polyester resin, the prepared dual-curing hot-pressing insulating film has a simple structure and has good flame retardant properties, good high temperature and high humidity resistance properties, and good thermal shock properties. The FFC prepared with the dual-curing hot-pressing insulating film provided by the present invention has excellent comprehensive properties. There are no bubbles around the wires of the prepared FFC, and there is no obvious glue overflow at the wire terminals. The initial peel strength is 114-130 gf / mm. After the high temperature and high humidity test, there are no bubbles around the wires of the FFC, and there is no glue opening at the wire edge. The peel strength is 100-117 gf / mm. The resistance value between adjacent wires is >500 MΩ. After the thermal shock test, there are no bubbles around the wires of the FFC, and there is no obvious glue overflow at the wire terminals. The peel strength is 95-125 gf / mm. After the flame retardancy test, its flame retardant effect reaches VTM-0.

[0178] Compared with Application Example 1, if the content of the oligo-polyol in the photocurable polyester resin, which is the preparation raw material of the adhesive layer of the dual-curing hot-pressing insulating film in the FFC, is too small (Application Example 8) or the content of the oligo-polyol is too large (Application Example 9), the comprehensive performance of the prepared dual-curing hot-pressing insulating film is poor, and the FFC prepared therefrom has poor high temperature and high humidity resistance properties and thermal shock properties.

[0179] Compared with Application Example 1, if the content of maleic anhydride in the photocurable polyester resin, which is the preparation raw material of the adhesive layer of the dual-curing hot-pressing insulating film in the FFC, is too small (Application Example 10) or the content of maleic anhydride is too large (Application Example 11), the comprehensive performance of the prepared dual-curing hot-pressing insulating film is poor, and the FFC prepared therefrom has poor high temperature and high humidity resistance properties and thermal shock properties.

[0180] Compared with Application Example 3, if the content of epoxy resin in the dual-curing hot-pressing insulating film for preparing the FFC is too small (Application Comparative Example 1) or the content of epoxy resin is too large (Application Comparative Example 2), or the content of photoinitiator in the dual-curing hot-pressing insulating film for preparing the FFC is too small (Application Comparative Example 3) or the content of flame retardant is too large (Application Comparative Example 4), the comprehensive performance of the prepared dual-curing hot-pressing insulating film is poor, and the FFC prepared therefrom has poor high temperature and high humidity resistance properties, thermal shock properties, and flame retardancy.

[0181] In summary, in the present invention, by designing the raw materials for preparing the adhesive layer in the dual-curing hot-pressing insulating film, and further by using the photocurable polyester resin, the prepared dual-curing hot-pressing insulating film has a simple structure and has good flame retardancy, good high-temperature and high-humidity resistance, and good thermal shock resistance. The FFC prepared from the dual-curing hot-pressing insulating film provided by the present invention has excellent comprehensive performance.

[0182] The applicant declares that the present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A double-curing hot-pressing insulating film for FFC, characterized in that, The double-curing hot-pressing insulating film includes a substrate layer and an adhesive layer that are bonded together; The raw materials for preparing the adhesive layer include the following components in parts by weight: 100 parts of a photocurable polyester resin, 3 to 20 parts of an acrylic rubber, 5 to 30 parts of an epoxy resin, 0.05 to 1 part of a photoinitiator, 2 to 15 parts of a curing agent, and 30 to 120 parts of a flame retardant; The raw materials for preparing the photocurable polyester resin include: a dibasic acid monomer and / or an acid anhydride, a diol monomer, an oligo-polyol, and maleic anhydride; The photocurable polyester resin is prepared by the following method, and the method includes the following steps: (1) In an atmosphere of a protective gas, a dibasic acid and / or an acid anhydride and a diol are placed in a reaction kettle for an esterification reaction to obtain an esterified product; (2) After adding an oligo-polyol to the reaction system in step (1), mixing, and performing a polymerization reaction to obtain a saturated polyester resin; (3) Adding maleic anhydride to the reaction system in step (2) for a modification reaction to obtain the photocurable polyester resin; Based on the mass percentage content of the esterified product being 100%, the mass percentage content of the oligo-polyol is 5% to 30%; Based on the molar percentage content of hydroxyl groups in the saturated polyester resin being 100%, the molar percentage content of maleic anhydride is 1% to 4%.

2. The dual-curing hot-pressing insulating film according to claim 1, wherein, The dibasic acid monomer is selected from any one or a combination of at least two of phthalic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, adipic acid, azelaic acid, or sebacic acid.

3. The dual-curing hot-pressing insulation film according to claim 1, wherein, The acid anhydride is selected from any one or a combination of at least two of phthalic anhydride, succinic anhydride, adipic anhydride, azelaic anhydride, or trimellitic anhydride.

4. The dual-curing hot-pressing insulating film according to claim 1, wherein, The diol is an alkylene diol with the number of carbon atoms ≥ 3.

5. The dual-curing hot-pressing insulation film according to claim 1, characterized in that The diol is selected from any one or a combination of at least two of polypropylene glycol, 2-methyl-1,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-2-ethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, or bisphenol A bis(2-hydroxyethyl) ether.

6. The dual-curing hot-pressing insulating film according to claim 1, wherein The oligo-polyol is selected from any one or a combination of at least two of polypropylene glycol, polytetrahydrofuran glycol, polycarbonate diol, or polycaprolactone diol.

7. The dual-curing hot-pressing insulating film according to claim 1, wherein The number-average molecular weight of the oligo-polyol is 500 to 3000.

8. The dual-curing hot-pressing insulating film according to claim 1, wherein, The glass transition temperature of the photocurable polyester resin is 0 to 40 °C.

9. The dual-curing hot-pressing insulating film according to claim 1, wherein, The molar ratio of the dibasic acid and / or the acid anhydride to the diol is 1:(1.2 to 1.4).

10. The dual-curing hot-pressing insulating film according to claim 1, wherein The limiting viscosity IV of the saturated polyester resin is 0.3 to 1.0 dl / g; The glass transition temperature of the saturated polyester resin is 0 to 40 °C.

11. The dual-curing hot-pressing insulating film according to claim 1, wherein The acrylic rubber is selected from any one or a combination of at least two of polyethylene-acrylate rubber, polyacrylate rubber, or acrylic block copolymer.

12. The dual-curing hot-pressing insulating film according to claim 1, wherein The epoxy resin is selected from any one or a combination of at least two of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic type epoxy resin, phenol-biphenyl type epoxy resin, or dicyclopentadiene phenol type epoxy resin.

13. The dual-curing hot-pressing insulating film according to claim 1, wherein The curing agent is a blocked isocyanate curing agent.

14. The dual-curing hot-pressing insulating film according to claim 1, wherein, The flame retardant is selected from any one or a combination of at least two of bromine-based flame retardants, phosphorus-based flame retardants, phosphorus-aluminum-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, metal hydroxide-based flame retardants, metal oxide flame retardants, or metal boride flame retardants.

15. The double-curing hot-pressing insulating film according to claim 1, wherein The preparation raw materials of the adhesive layer further include 0.1 to 1 part of a curing accelerator, 0.1 to 2 parts of an antioxidant, and 0.1 to 2 parts of a dispersion aid; The curing accelerator is selected from organic amine-based curing accelerators and / or metal salt-based curing accelerators; The dispersion aid is selected from any one or a combination of at least two of titanate coupling agents, aluminate coupling agents, organosilane coupling agents, organic chromium complex coupling agents, or borate coupling agents.

16. A method for preparing a dual-curing hot-pressing insulating film according to any one of claims 1 to 15, characterized in that, The preparation method includes the following steps: Mix the preparation raw materials of the adhesive layer with a solvent to obtain a mixed solution, and then coat it on one side surface of the substrate and dry it to obtain the dual-curing hot-pressed insulating film.

17. The preparation method according to claim 16, wherein The substrate is a corona-treated PET film; The specific drying method includes: drying at 70 to 90 °C for 2 to 5 min, and then heating to 110 to 130 °C and drying for 2 to 5 min; The thickness of the adhesive layer of the dual-curing hot-pressed insulating film is 15 to 80 μm.

18. An FFC, characterized in that, The FFC includes a wire and the dual-curing hot-pressed insulating film as described in any one of claims 1 to 15 covering both sides of the wire surface.

19. A method for preparing an FFC as described in claim 18, characterized in that, The preparation method includes the following steps: Place one piece of the dual-curing hot-pressed insulating film on the upper surface and the lower surface of the wire respectively. After rolling, perform photocuring and then thermal curing in sequence to obtain the FFC; The temperature of the rolling is 160 to 200 °C; The pressure of the rolling is 0.3 to 0.6 MPa; The time of the rolling is 2 to 3 s; The time of the photocuring is 2 to 3 s; The light intensity of the photocuring is 800~4000 mJ / cm 2 ; The temperature of the thermal curing is 90 to 130 °C; The time of the thermal curing is 1 to 3 h.

20. Application of an FFC as described in claim 18 in the field of new energy vehicles.

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