Resin composition for flexible flat cable, and insulating adhesive film thereof, and use thereof

Abstract

The present application provides a kind of resin composition for flexible flat cable and its insulating adhesive film and its application, the resin composition for flexible flat cable includes the following weight parts of components: saturated polyester 20-30 parts, carboxyl polyurethane 10-20 parts, polyacrylate resin 5-10 parts, epoxy resin 20-30 parts, curing agent 10-15 parts.The insulating adhesive film prepared by the resin composition described in the present application has low-temperature press-bonding, excellent filling and reliability, compared with similar products on the market, the press-bonding temperature is reduced by more than 50 DEG C, which is beneficial to improve the reliability of FFC.

Description

Technical Field

[0001] This invention belongs to the technical field of insulating film for flexible flat cables, and relates to a resin composition for flexible flat cables, its insulating film, and its application. Background Technology

[0002] The power source of most new energy vehicles relies on large-capacity power batteries. Power batteries are generally composed of multiple cells connected together. The healthy and stable working state of each individual cell is an important guarantee for the safe operation of the power battery.

[0003] Flexible printed circuit boards (FPCs) are widely used in power batteries as signal acquisition lines due to their advantages such as lightweight, high reliability, high integration, and automated production. They are mainly responsible for collecting signals such as the working voltage, temperature, and current of the battery cells. However, as the size of power battery modules increases and the demand for cost reduction becomes stronger, the high cost and unsuitability for large-size manufacturing of FPCs may lead to their further replacement.

[0004] Flexible flat cable (FFC) is a new type of data cable made by hot-pressing rolls of PET insulating film and extremely thin flat copper wire through an automated production line. It boasts advantages such as flexibility, easy bending and folding, thinness, small size, simple connection, and convenient disassembly, making it widely used in consumer electronics products such as printers, digital cameras, and laptops. Roll-produced FFC can accommodate large-size manufacturing and is less expensive than FPC, making it a viable alternative to FPC in power batteries. However, traditional FFC is only used in consumer electronics and cannot meet the high reliability requirements of power batteries.

[0005] Improving the reliability of insulating films used in FFC (Free Fusion Cushions) to meet the high reliability requirements of power batteries has become a research hotspot in the industry, with numerous research reports published in documents such as CN107995891A, CN112877006A, and CN113881361A. However, currently available insulating films for FFC used in power batteries generally suffer from excessively high pressing temperatures. To ensure good adhesion and filling properties of the adhesive layer during short-term rolling, the processing temperature reaches nearly 200°C. FFC insulating films typically use thermoplastic PET film, which is not heat-resistant; therefore, excessively high processing temperatures can lead to irreversible damage to the insulating film, threatening the safety of the power battery.

[0006] Therefore, developing a highly reliable resin composition that can be low-temperature pressed and used in insulating films for FFCs is crucial for the successful application of FFCs in power batteries. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a resin composition for flexible flat cables, an insulating film thereof, and its applications. The insulating film prepared from the resin composition of the present invention exhibits low-temperature pressing capability, excellent filling properties, and reliability.

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

[0009] On one hand, the present invention provides a resin composition for flexible flat cables, the resin composition for flexible flat cables comprising the following components in parts by weight:

[0010] 20-30 parts saturated polyester, 10-20 parts carboxylated polyurethane, 5-10 parts polyacrylate resin, 20-30 parts epoxy resin, and 10-15 parts curing agent.

[0011] The FFC processing mainly involves two hot-pressing stages. The first hot-pressing stage primarily serves to temporarily bond the copper wires to the insulating film, while the second hot-pressing stage is the forming stage, mainly serving to bond the adhesive layer to the copper wires. In this invention, the temperature of the first hot-pressing stage is ≤60℃, and the temperature of the second hot-pressing stage is ≤150℃. Processing at these temperatures ensures that the PET film is not damaged, resulting in FFC with excellent reliability.

[0012] In the resin composition of the present invention, the glass transition temperature of the polyacrylate resin is lower than that of room temperature, which is beneficial for the low-temperature false bonding and venting of the copper wire and the insulating film in the first hot pressing process, and there will be no bubbles during room temperature molding; the saturated polyester has a low softening point, which is beneficial for the melting of the adhesive layer and the bonding and fixing between it and the copper wire in the second hot pressing process; the carboxyl polyurethane and epoxy resin have strong reactivity, and under the action of the curing agent, they can form a network structure, which is beneficial for improving the adhesive layer's resistance to humid heat aging and high and low temperature impact performance.

[0013] In the resin composition of the present invention, the amount of the saturated polyester can be 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, or 30 parts by weight; the amount of the carboxylated polyurethane can be 10 parts by weight, 12 parts by weight, 15 parts by weight, 18 parts by weight, or 20 parts by weight; the amount of the polyacrylate resin can be 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, or 10 parts by weight; the amount of the epoxy resin can be 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, or 30 parts by weight; and the amount of the curing agent can be 10 parts by weight, 12 parts by weight, 14 parts by weight, or 15 parts by weight.

[0014] The "parts" and "parts by weight" used in this invention are calculated based on solid content and do not include solvents, dispersants, etc.

[0015] Preferably, the number-average molecular weight of the saturated polyester resin is 10,000 to 30,000, for example, 10,000, 12,000, 15,000, 18,000, 20,000, 23,000, 25,000, 28,000, or 30,000. In this invention, if the molecular weight of the saturated polyester resin is too low, the cohesive strength of the adhesive layer is insufficient, and the peel strength is low; if the molecular weight of the saturated polyester is too high, the wettability of the adhesive layer deteriorates, the peel strength is also low, and the conformability deteriorates.

[0016] The number-average molecular weight of the present invention can be determined by gel permeation chromatography based on polystyrene calibration, referring to GB / T 21863-2008.

[0017] Preferably, the softening point of the saturated polyester resin is 100–120°C (e.g., 100°C, 110°C, or 120°C). In this invention, if the softening point of the saturated polyester is too low, excessive resin flow is likely to occur during the second stage of FFC hot pressing; if the softening point of the saturated polyester is too high, insufficient melting and poor fluidity will result in insufficient peel strength and poor conformability during the second stage of FFC hot pressing.

[0018] Preferably, the saturated polyester resin has a hydroxyl value of 2 to 10 mgKOH / g (e.g., 2 mgKOH / g, 4 mgKOH / g, 6 mgKOH / g, 8 mgKOH / g or 10 mgKOH / g) and an acid value of 0 to 2 mgKOH / g (e.g., 0 mgKOH / g, 1.5 mgKOH / g, 1.8 mgKOH / g, 2 mgKOH / g).

[0019] Preferably, the number-average molecular weight of the carboxylated polyurethane is 10,000 to 15,000, for example, 10,000, 11,000, 120,000, 13,000, or 15,000. In this invention, if the molecular weight of the carboxylated polyurethane is too low, the cohesive strength and adhesive layer toughness are insufficient, resulting in reduced peel strength; if the molecular weight of the carboxylated polyurethane is too high, the hot-pressing fluidity is poor, the adhesive layer peel strength is low, and the conformability is poor.

[0020] Preferably, the acid value of the carboxyl polyurethane is 30-40 mgKOH / g (e.g., 30 mgKOH / g, 35 mgKOH / g, 38 mgKOH / g, or 40 mgKOH / g). In this invention, if the acid value of the carboxyl polyurethane is too low, the crosslinking density of the system will be insufficient, resulting in poor resistance to damp heat aging; if the acid value of the carboxyl polyurethane is too high, the crosslinking density of the system will be too high, the adhesive layer will become brittle, and the peel strength will decrease.

[0021] Preferably, the weight-average molecular weight of the polyacrylate resin is 500,000 to 900,000, for example, 500,000, 800,000, or 900,000. In this invention, if the molecular weight of the polyacrylate resin is too high, the conformability will be poor and the peel strength will be low; if the molecular weight of the polyacrylate resin is too low, the film-forming properties after dissolution will be poor and the peel strength will be low.

[0022] Preferably, the glass transition temperature of the polyacrylate resin is -40 to -10°C, for example -40°C, -35°C, -30°C, -20°C, or -10°C.

[0023] Preferably, the polyacrylate resin is a polyacrylate resin containing hydroxyl and / or carboxyl groups.

[0024] Preferably, the hydroxyl-containing polyacrylate resin has a hydroxyl value of 20–40 mg KOH / g (e.g., 20 mg KOH / g, 23 mg KOH / g, 25 mg KOH / g, 28 mg KOH / g, 30 mg KOH / g, 35 mg KOH / g, 38 mg KOH / g, or 40 mg KOH / g); and the carboxyl-containing polyacrylate resin has an acid value of 20–40 mg KOH / g (e.g., 20 mg KOH / g, 23 mg KOH / g, 25 mg KOH / g, 28 mg KOH / g, 30 mg KOH / g, 35 mg KOH / g, 38 mg KOH / g, or 40 mg KOH / g).

[0025] Preferably, the epoxy resin includes any one or a combination of at least two of linear phenolic epoxy resin, bisphenol A type phenolic epoxy resin, or o-cresol type phenolic epoxy resin.

[0026] Preferably, the epoxy equivalent of the epoxy resin is 150 to 220 g / eq, for example, 150 g / eq, 170 g / eq, 190 g / eq, 200 g / eq, 210 g / eq or 220 g / eq.

[0027] Preferably, the curing agent is an amine-based curing agent.

[0028] Preferably, the curing agent is selected from any one or a combination of at least two of dicyandiamide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, or 4,4'-diaminodiphenylmethane.

[0029] Preferably, the resin composition for flexible flat cables further includes 10 to 50 parts by weight (e.g., 10 parts by weight, 15 parts by weight, 18 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight or 50 parts by weight) of a flame retardant.

[0030] Preferably, the flame retardant is a phosphorus-containing flame retardant.

[0031] On the other hand, the present invention provides a resin composition liquid obtained by dissolving or dispersing the aforementioned resin composition for flexible flat cables in an organic solvent.

[0032] Preferably, the organic solvent is selected from any one or a combination of at least two of acetone, butanone, toluene, ethanol, isopropanol, cyclohexanone, ethylene glycol methyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, or ethyl acetate.

[0033] Preferably, the solid content of the resin composition in the resin composition liquid is 30-60 wt%, for example 30 wt%, 35 wt%, 38 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 58 wt%, or 60 wt%.

[0034] On the other hand, the present invention provides a flexible flat cable insulating film, the flexible flat cable insulating film comprising a base film, an adhesive layer and a protective layer stacked sequentially, the adhesive layer comprising the resin composition for flexible flat cables as described above.

[0035] Preferably, the base film is selected from one of PET film, PI film, PEN film or PBT film.

[0036] Preferably, the thickness of the base film is 10 to 100 μm, for example, 10 μm, 20 μm, 30 μm, 50 μm, 70 μm, 80 μm, 90 μm or 100 μm.

[0037] Preferably, the thickness of the adhesive layer is 10 to 100 μm, for example, 10 μm, 20 μm, 30 μm, 50 μm, 70 μm, 80 μm, 90 μm or 100 μm.

[0038] Preferably, the protective layer is selected from one of release film, release paper, electrostatic film, or low-tack film.

[0039] In this invention, the preparation method of the flexible flat cable insulating film is as follows: the resin composition components as described above are mixed evenly to form a liquid resin composition liquid, the liquid resin composition liquid is coated on the surface of the base film using a coating machine, and after drying, it is laminated with the protective layer to obtain the insulating film for FFC.

[0040] On the other hand, the present invention provides the use of the resin composition for flexible flat cables or the insulating film for flexible flat cables as described above in the preparation of flexible flat cables.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The insulating film prepared by the resin composition of the present invention has the characteristics of low-temperature pressing, excellent filling properties and reliability. Compared with similar products on the market, the pressing temperature is reduced by more than 50°C, which is beneficial to improving the reliability of FFC. Detailed Implementation

[0043] 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.

[0044] The source information of the raw materials used in the examples is as follows:

[0045] (1) Saturated polyester

[0046] SK Corporation of South Korea's ES410 has a number average molecular weight of 16,000, a softening point of 120℃, a hydroxyl value of 6 mgKOH / g, and an acid value of 2 mgKOH / g.

[0047] SK Corporation of South Korea's ES300 has a number average molecular weight of 28,000, a softening point of 102℃, a hydroxyl value of 3 mgKOH / g, and an acid value of 0 mgKOH / g.

[0048] SK Corporation of South Korea's ES403 has a number average molecular weight of 9000, a softening point of 115℃, a hydroxyl value of 7 mgKOH / g, and an acid value of 1 mgKOH / g.

[0049] SK Corporation of South Korea's ES320 has a number average molecular weight of 33,000, a softening point of 110℃, a hydroxyl value of 2 mgKOH / g, and an acid value of 2 mgKOH / g.

[0050] SK Corporation of South Korea's ES110 has a number average molecular weight of 18,000, a softening point of 135℃, a hydroxyl value of 4 mgKOH / g, and an acid value of 1 mgKOH / g.

[0051] Suzhou Hanhai Company's AL150 has a number average molecular weight of 21,000, a softening point of 93℃, a hydroxyl value of 6 mgKOH / g, and an acid value of 1 mgKOH / g.

[0052] (2) Carboxylated polyurethane

[0053] TOYOBO SD-5000 from Japan has a number-average molecular weight of 13,000 and an acid value of 35 mgKOH / g.

[0054] TOYOBO UR-3500 from Japan has a number-average molecular weight of 40,000 and an acid value of 35 mgKOH / g.

[0055] The carboxylated polyurethane prepared in Example 3 of patent CN101146839A has a number-average molecular weight of 8700 and an acid value of 39.2 mgKOH / g. In the following examples, it will be referred to as PU-A.

[0056] The carboxylated polyurethane prepared by Synthesis Example 1 of Patent CN102445843A had a number-average molecular weight of 10400 and an acid value of 41.5 mgKOH / g. In the following examples, it is referred to as PU-B.

[0057] The carboxylated polyurethane prepared in Comparative Example 1 of Patent CN101133096A has a number average molecular weight of 12000 and an acid value of 21.5 mgKOH / g. In the following examples, it is referred to as PU-C.

[0058] (3) Polyacrylate resin

[0059] Nagase Chemtex SG-280DR (Japan): Glass transition temperature -29℃, weight-average molecular weight 900,000, acid value 30 mg KOH / g.

[0060] Nagase Chemtex WS-023 (Japan): Glass transition temperature -10℃, weight-average molecular weight 500,000, acid value 20 mgKOH / g.

[0061] Nagase Chemtex SG-790 from Japan has a glass transition temperature of -32°C, a weight-average molecular weight of 500,000, and a hydroxyl value of 40 mg KOH / g.

[0062] Nagase Chemtex SG-600DR (Japan): Glass transition temperature -37℃, weight-average molecular weight 1,200,000, hydroxyl value 20 mgKOH / g.

[0063] The Nagase Chemtex SG-700AS has a glass transition temperature of 5°C, a weight-average molecular weight of 400,000, and an acid value of 34 mg KOH / g.

[0064] (4) Phosphorus-containing flame retardants

[0065] Clariant Chemicals of Switzerland, Exolit OP-935.

[0066] Example 1

[0067] A resin composition, by weight, comprises: 20 parts of saturated polyester ES410, 10 parts of carboxylated polyurethane SD-5000, 5 parts of polyacrylate resin SG-280DR, 20 parts of linear phenolic epoxy resin, 10 parts of dicyandiamide, and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0068] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0069] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0070] Example 2

[0071] A resin composition, by weight, comprises: 30 parts of saturated polyester ES300, 20 parts of carboxylated polyurethane SD-5000, 10 parts of polyacrylate resin WS-023, 30 parts of bisphenol A type phenolic epoxy resin, 15 parts of 4,4'-diaminodiphenylmethane, and 50 parts of flame retardant Exolit OP-935.

[0072] The above-mentioned components and the organic solvent methyl ethyl ketone are mixed and dispersed under high shear to prepare a resin composition liquid with a solid content of 60 wt%. The resin composition liquid is then coated onto the insulating substrate PI using a coating device.

[0073] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 160°C for 2 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0074] Example 3

[0075] A resin composition, by weight, comprises: 25 parts of saturated polyester ES300, 15 parts of carboxylated polyurethane SD-5000, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0076] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0077] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0078] Example 4

[0079] A resin composition, by weight, comprises: 25 parts of saturated polyester ES320, 15 parts of carboxylated polyurethane SD-5000, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0080] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0081] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0082] Example 5

[0083] A resin composition, by weight, comprises: 25 parts of saturated polyester ES403, 15 parts of carboxylated polyurethane SD-5000, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0084] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0085] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0086] Example 6

[0087] A resin composition, by weight, comprises: 25 parts of saturated polyester ES110, 15 parts of carboxylated polyurethane SD-5000, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A type phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0088] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0089] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0090] Example 7

[0091] A resin composition, by weight, comprises: 25 parts of saturated polyester AL150, 15 parts of carboxylated polyurethane SD-5000, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A type phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0092] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0093] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0094] Example 8

[0095] A resin composition, by weight, comprises: 25 parts of saturated polyester ES300, 15 parts of carboxylated polyurethane UR-3500, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0096] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0097] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0098] Example 9

[0099] A resin composition, by weight, comprises: 25 parts of saturated polyester ES300, 15 parts of carboxylated polyurethane PU-A, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0100] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0101] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0102] Example 10

[0103] A resin composition, by weight, comprises: 25 parts of saturated polyester ES300, 15 parts of carboxylated polyurethane PU-B, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0104] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0105] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0106] Example 11

[0107] A resin composition, by weight, comprises: 25 parts of saturated polyester ES300, 15 parts of carboxylated polyurethane PU-C, 8 parts of polyacrylate resin SG-790, 25 parts of bisphenol A type phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0108] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0109] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0110] Example 12

[0111] A resin composition, by weight, comprises: 25 parts of saturated polyester ES300, 15 parts of carboxylated polyurethane SD-5000, 8 parts of polyacrylate resin SG-600DR, 25 parts of bisphenol A phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0112] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0113] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0114] Example 13

[0115] A resin composition, by weight, comprises: 25 parts of saturated polyester ES300, 15 parts of carboxylated polyurethane SD-5000, 8 parts of polyacrylate resin SG-700AS, 25 parts of bisphenol A type phenolic epoxy resin, 12 parts of 4,4'-diaminodiphenylmethane, and 30 parts of flame retardant Exolit OP-935.

[0116] The above-mentioned components and organic solvent toluene are mechanically stirred and dispersed to prepare a resin composition liquid with a solid content of 40 wt%. The resin composition liquid is then coated onto the insulating substrate PEN using a coating device.

[0117] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 130°C for 7 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0118] Example 14

[0119] A resin composition, by weight, comprises: 20 parts of saturated polyester ES410, 10 parts of carboxylated polyurethane SD-5000, 5 parts of polyacrylate resin SG-280DR, 20 parts of linear phenolic epoxy resin, 10 parts of isocyanate curing agent (TPAB80E, blocked isocyanate resin, HDI type, Asahi Kasei, Japan), and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0120] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0121] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0122] Example 15

[0123] A resin composition, by weight, comprises: 20 parts of saturated polyester ES410, 10 parts of carboxylated polyurethane SD-5000, 5 parts of polyacrylate resin SG-280DR, 20 parts of linear phenolic epoxy resin, 10 parts of isocyanate curing agent (C-HXR, isocyanate resin, HDI type, TOSOH Japan), and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0124] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0125] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0126] Example 16

[0127] A resin composition, by weight, comprises: 20 parts of saturated polyester ES410, 10 parts of carboxylated polyurethane SD-5000, 5 parts of polyacrylate resin SG-280DR, 20 parts of linear phenolic epoxy resin, and a fatty amine curing agent (Baxxodur). TM 10 parts of EC280 (BASF) and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0128] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0129] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0130] Comparative Example 1

[0131] A resin composition, by weight, comprises: 10 parts of carboxylated polyurethane SD-5000, 5 parts of polyacrylate resin SG-280DR, 20 parts of linear phenolic epoxy resin, 10 parts of dicyandiamide, and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0132] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0133] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0134] Comparative Example 2

[0135] A resin composition, by weight, comprises: 20 parts of saturated polyester ES410, 5 parts of polyacrylate resin SG-280DR, 20 parts of linear phenolic epoxy resin, 10 parts of dicyandiamide, and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0136] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0137] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0138] Comparative Example 3

[0139] A resin composition, by weight, comprises: 20 parts of saturated polyester ES410, 10 parts of carboxylated polyurethane SD-5000, 20 parts of linear phenolic epoxy resin, 10 parts of dicyandiamide, and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0140] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0141] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0142] Comparative Example 4

[0143] A resin composition, by weight, comprises: 20 parts of saturated polyester ES410, 10 parts of carboxylated polyurethane SD-5000, 5 parts of polyacrylate resin SG-280DR, 10 parts of dicyandiamide, and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0144] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0145] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0146] Comparative Example 5

[0147] A resin composition, by weight, comprises: 20 parts of unsaturated polyester (type 196 unsaturated polyester, CAS No. 26098-37-3), 10 parts of carboxylated polyurethane SD-5000, 5 parts of polyacrylate resin SG-280DR, 20 parts of linear phenolic epoxy resin, 10 parts of dicyandiamide, and 10 parts of phosphorus-containing flame retardant Exolit OP-935.

[0148] The above-mentioned components and organic solvent acetone are emulsified and stirred to prepare a resin composition liquid with a solid content of 30 wt%. The resin composition liquid is then coated onto an insulating substrate PET using a coating device.

[0149] The insulating substrate coated with the resin composition solution is then passed through an online drying oven and heated at 80°C for 10 minutes; after removing the organic solvent, it is wound up to obtain the insulating film.

[0150] The adhesive layer thickness was uniformly set to 75 μm, and the properties of the insulating films prepared in the examples and comparative examples were evaluated by parallel comparison. The specific test methods are as follows:

[0151] Flexible flat cables were prepared by rolling the insulating film prepared in the above examples and comparative examples with copper wire coils. The specific processing parameters were: the first stage false bonding temperature was 60°C, the second stage pressing temperature was 150°C, the pressure was 0.5MPa, the line speed was 3m / min, and the ratio of adhesive layer thickness to copper wire thickness was 0.7.

[0152] (1) Coverability: Take a slice of FFC sample and observe whether there are air bubbles in the cross section. If there are no air bubbles, the coverability is qualified; if there are air bubbles, the coverability is unqualified.

[0153] (2) Peel strength: Take an FFC sample, pull the copper wire to test the 90° peel strength, and test the rate of 50mm / min.

[0154] (3) Reliability: After 2000 hours of double 85 treatment and high and low temperature shock (-40℃ / 30min~125℃ / 30min, 2000 cycles), the FFC appearance is free of delamination and blistering, and the 90° peel strength decreases by ≤10% compared with the initial state, which is qualified; otherwise, it is unqualified.

[0155] The performance of the flexible flat cables provided in Examples 1-16 and Comparative Examples 1-5 was tested according to the above performance test method. The test results are shown in Table 1.

[0156] Table 1

[0157]

[0158]

[0159] As can be seen from the data in Table 1, the resin compositions provided in Examples 1-3 of the present invention and the insulating films prepared therefrom have good conformability and reliability, and the peel strength is ≥2.1N / mm.

[0160] When the number-average molecular weight and softening point of the saturated polyester resin used in the resin compositions of Examples 4-7 are not within the preferred range, the conformability or peel strength of the insulating films prepared by them are not as good as those in Example 3.

[0161] When the number-average molecular weight and acid value of the carboxylated polyurethane used in the resin compositions of Examples 8-11 are not within the preferred range, the conformability, peel strength or reliability of the insulating films prepared by them are not as good as those of Example 3.

[0162] When the weight-average molecular weight of the polyacrylate resin used in the resin compositions of Examples 12-13 is not within the preferred range, the conformability or peel strength of the insulating films prepared therefrom are not as good as those in Example 3.

[0163] Compared to Example 1, Examples 14-16 used a blocked isocyanate curing agent, an isocyanate curing agent, and a fatty amine curing agent, respectively. After the blocked isocyanate curing agent was desealed, bubbles were generated in the adhesive layer. The isocyanate and fatty amine curing agents had high reactivity, which led to premature cross-linking of the adhesive layer. Ultimately, the conformability, peel strength, or reliability of the insulating film prepared by them were not as good as those in Example 1.

[0164] Compared to Example 1, Comparative Examples 1-4 do not contain saturated polyester, carboxylated polyurethane, polyacrylate resin and linear phenolic epoxy resin, respectively, resulting in insulating films prepared therefrom having inferior conformability, peel strength and reliability compared to Example 1.

[0165] In Comparative Example 5, unsaturated polyester resin was used instead of saturated polyester resin compared to Example 1, resulting in insulating films prepared with this method having inferior conformability, peel strength, and reliability compared to those of Example 1.

[0166] The applicant declares that this invention illustrates the resin composition for flexible flat cables, its insulating film, and its applications through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A resin composition for flexible flat cables, characterized in that, The resin composition for flexible flat cables comprises the following components in parts by weight: Saturated polyester 20-30 parts, carboxylated polyurethane 10-20 parts, polyacrylate resin 5-10 parts, epoxy resin 20-30 parts, curing agent 10-15 parts; The number-average molecular weight of the carboxylated polyurethane is 10,000 to 15,000. The acid value of the carboxyl polyurethane is 30~40 mgKOH / g; The number-average molecular weight of the saturated polyester resin is 10,000 to 30,000. The softening point of the saturated polyester resin is 100~120℃; The weight-average molecular weight of the polyacrylate resin is 500,000 to 900,000. The glass transition temperature of the polyacrylate resin is -40 to -10°C. The curing agent is selected from any one or a combination of at least two of dicyandiamide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, or 4,4'-diaminodiphenylmethane.

2. The resin composition for flexible flat cables according to claim 1, characterized in that, The saturated polyester resin has a hydroxyl value of 2~10 mgKOH / g and an acid value of 0~2 mgKOH / g.

3. The resin composition for flexible flat cables according to claim 1, characterized in that, The polyacrylate resin is a polyacrylate resin containing hydroxyl and / or carboxyl groups.

4. The resin composition for flexible flat cables according to claim 3, characterized in that, The hydroxyl-containing polyacrylate resin has a hydroxyl value of 20-40 mg KOH / g; the carboxyl-containing polyacrylate resin has an acid value of 20-40 mg KOH / g.

5. The resin composition for flexible flat cables according to claim 1, characterized in that, The epoxy resin includes any one or a combination of at least two of linear phenolic epoxy resin, bisphenol A type phenolic epoxy resin, or o-cresol type phenolic epoxy resin.

6. The resin composition for flexible flat cables according to claim 1, characterized in that, The epoxy equivalent of the epoxy resin is 150~220 g / eq.

7. The resin composition for flexible flat cables according to claim 1, characterized in that, The resin composition for flexible flat cables also includes 10 to 50 parts by weight of flame retardant.

8. The resin composition for flexible flat cables according to claim 7, characterized in that, The flame retardant is a phosphorus-containing flame retardant.

9. A resin composition liquid, characterized in that, It is obtained by dissolving or dispersing the resin composition for flexible flat cables as described in any one of claims 1-8 in an organic solvent.

10. The resin composition liquid according to claim 9, characterized in that, The organic solvent is selected from any one or a combination of at least two of acetone, butanone, toluene, ethanol, isopropanol, cyclohexanone, ethylene glycol methyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, or ethyl acetate.

11. The resin composition liquid according to claim 9, characterized in that, The solid content of the resin composition in the resin composition liquid is 30~60 wt%.

12. A flexible flat cable insulating film, characterized in that, The flexible flat cable insulating film comprises a base film, an adhesive layer, and a protective layer stacked sequentially, wherein the adhesive layer comprises a resin composition for flexible flat cables as described in any one of claims 1-8.

13. The flexible flat cable insulating film according to claim 12, characterized in that, The base film is selected from one of PET film, PI film, PEN film or PBT film.

14. The flexible flat cable insulating film according to claim 12, characterized in that, The thickness of the base film is 10~100 μm.

15. The flexible flat cable insulating film according to claim 12, characterized in that, The thickness of the adhesive layer is 10~100 μm.

16. The flexible flat cable insulating film according to claim 12, characterized in that, The protective layer is selected from one of release film, release paper, electrostatic film, or low-tack film.

17. The use of the resin composition for flexible flat cables according to any one of claims 1-8 or the insulating film for flexible flat cables according to any one of claims 12-16 in the preparation of flexible flat cables.

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