Resin composition and low-flow prepreg prepared using the same

Abstract

The application develops a new resin composition and a low-flow prepreg prepared by using the resin composition. While ensuring that the low-flow prepreg has excellent toughness and a low powder loss rate, the adhesion and the apparent flatness of the low-flow prepreg are significantly improved. Finally, the low-flow prepreg has excellent comprehensive performance, such as an overflow amount, toughness / powder loss rate, interlayer adhesion of the bonded sheet, apparent flatness of the bonded sheet, heat resistance and the like, and can be well used in rigid-flex combined printed circuit boards.

Description

TECHNICAL FIELD

[0001] The application relates to a low-flow prepreg for use as a bonding layer material in rigid-flex printed circuit board production, and belongs to the technical field of printed circuit boards. BACKGROUND

[0002] Rigid-flex printed circuit board, also known as rigid-flex board, is a combination of soft board and hard board, which combines a thin layer of flexible bottom layer and rigid bottom layer, and is laminated into a single component to form a circuit board. Rigid-flex board changes the traditional flat design concept to a three-dimensional 3D space concept, which brings great convenience to product design, but also brings great challenges. Rigid-flex printed circuit board is a kind of printed circuit board in great demand and development at present, and its application range mainly includes: consumer electronics field such as mobile phones, wireless earphones and AR glasses, and application fields such as automobiles, military industry, industrial control and medical treatment.

[0003] In the prior art, a typical (four-layer) rigid-flex printed circuit board has a polyimide core, and copper foils are coated on the upper and lower surfaces of the core. The outer rigid layers are composed of single-sided FR4 (glass fiber board), which are laminated on both sides of the flexible core to form a multi-layer PCB. When manufacturing a multi-layer rigid-flex board, the processing technology of the flexible layer is completely different from that of the outer FR4 layer. Each layer made of different materials must be gathered together by lamination, and then drilled and electroplated. When manufacturing rigid-flex printed circuit boards, adhesive materials are needed to bond the soft board and the hard board together. The most commonly used adhesive material at present is low-flow prepreg (also known as low-flow prepreg, low-flow adhesive sheet). Compared with conventional FR-4 prepreg, low-flow prepreg needs to have the characteristics of extremely small or almost no flow under high temperature and high pressure, and also needs to have good adhesion, excellent toughness and low powder dropping, and excellent apparent flatness. Due to the characteristics of extremely small or almost no flow of low-flow prepreg under high temperature and high pressure, it is usually necessary to improve the reaction degree of the resin system, which will lead to the decrease of the bonding capacity of the adhesive sheet, which becomes a pair of contradictions. Therefore, how to ensure that the low-flow prepreg has extremely small or almost no flow while having excellent bonding capacity has become a major technical problem of low-flow prepreg.

[0004] To solve the above technical problems, the early low-flow prepreg realizes low-flow by increasing the baking time to improve the reaction degree on the basis of conventional FR-4, and has the problems of insufficient adhesion, insufficient toughness and high powder loss rate. In order to improve the toughness and powder loss rate of the low-flow prepreg, the prior art usually adds rubber to the resin system for toughening, such as core-shell rubber and carboxyl-terminated butyronitrile rubber, to improve the toughness and powder loss rate of the low-flow prepreg. However, there are certain technical difficulties in using rubber for toughening modification: if the amount of rubber component is too small, the toughening effect cannot be achieved to improve the toughness and reduce the powder loss rate, and if the amount of rubber component is too large, the adhesion of the low-flow prepreg will be reduced. Due to the characteristics of the low-flow prepreg that the flow is extremely small or almost no flow under high temperature and high pressure, the low-flow prepreg cannot have good flowability and wettability under high temperature and high pressure like ordinary FR-4 prepreg, and the adhesion of the bonded sheet is particularly reduced when the amount of rubber component is too large.

[0005] On the other hand, due to the characteristics of the low-flow prepreg that the flow is extremely small or almost no flow, when the low-flow prepreg is used as a bonding material to prepare a rigid-flex combined board laminate, the flow of the low-flow prepreg is very small, and even if there is only a small defect on the surface of the low-flow prepreg, the low-flow prepreg cannot flow flat during lamination. Therefore, the low-flow prepreg requires very good surface flatness and cannot have any defects. The surface defects of the low-flow prepreg are the same as those of the ordinary FR-4 prepreg, which can be classified as bubbles, flow marks, fish eyes, stripes and cracks. Once the surface of the low-flow prepreg has defects, the flatness cannot meet the requirements, which will cause defects such as adhesion, voids and bubbles in the circuit board substrate after pressing, thereby greatly reducing the reliability of the circuit board.

[0006] Therefore, it is necessary to further improve the above problems and develop a new rubber-toughened resin composition and a low-flow prepreg made of the same, which can improve the adhesion of the low-flow prepreg, especially the interlayer adhesion of the low-flow prepreg, while ensuring that the low-flow prepreg has excellent toughness and low powder loss rate, and at the same time, improve the surface flatness of the low-flow prepreg, which obviously has positive practical significance. SUMMARY

[0007] The application aims to provide a resin composition and a low-flow prepreg prepared by using the same.

[0008] To achieve the above application purpose, the technical scheme adopted by the application is as follows: a resin composition, including the following components in terms of organic solid weight parts:

[0009] (a) epoxy resin, 100 parts by weight;

[0010] (b) an epoxy curing agent, 2-100 parts by weight;

[0011] (c) a curing accelerator, 0.05-1 parts by weight;

[0012] (d) a carboxyl nitrile rubber, 1-10% of the total amount of the above components (a), (b) and (c);

[0013] (e) an oxazoline compound, the oxazoline compound being added in an amount of 30-100% of component (d);

[0014] The method for preparing the resin composition is as follows:

[0015] S1, dissolving components (a) epoxy resin, (b) epoxy resin curing agent, (d) carboxyl nitrile rubber, (e) oxazoline compound, mixing them according to the proportion to prepare a resin mixture;

[0016] S2, pre-reacting the resin mixture at a temperature of 50-100°C for 2-30 hours to obtain a pre-reacted product;

[0017] S3, adding the dissolved component (c) curing accelerator to the pre-reacted product, stirring and mixing uniformly to obtain the resin composition.

[0018] In the above, the component (d) carboxyl nitrile rubber can be solid carboxyl nitrile rubber, liquid carboxyl nitrile rubber, and preferably solid carboxyl nitrile rubber.

[0019] In the above, the resin composition is used to prepare a low-flow prepreg, and the low-flow prepreg is used to prepare a rigid-flex printed circuit board.

[0020] In the above, in step S2, the pre-reaction temperature is preferably 55-90°C, more preferably 65-80°C, and can also be 60°C, 70°C, 75°C, 85°C, 88°C. The pre-reaction time is preferably 10-20 hours, more preferably 10-15 hours, and can also be 3 hours, 7 hours, 12 hours, 18 hours, 22 hours, 25 hours, 28 hours.

[0021] Preferably, the epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, tetraphenylethane epoxy resin, triphenylmethane epoxy resin, biphenyl type epoxy resin, naphthalene ring type epoxy resin, dicyclopentadiene type epoxy resin, isocyanate type epoxy resin, aralkyl linear phenolic aldehyde epoxy resin, bisphenol A phenolic aldehyde type epoxy resin, polyphenyl ether modified epoxy resin, alicyclic type epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin.

[0022] If the low-flow prepreg has high heat resistance requirement, then the composition should be composed of biphenyl type epoxy resin, naphthalene ring type epoxy resin, aralkyl linear phenolic aldehyde epoxy resin and other high heat resistance resins; if the low-flow prepreg has low dielectric property requirement, then the composition should be composed of dicyclopentadiene type epoxy resin, polyphenyl ether modified epoxy resin and other special epoxy resins.

[0023] Preferably, the epoxy curing agent is selected from one or more of aliphatic amine, aromatic amine, alicyclic amine, heterocyclic amine, aromatic anhydride, alicyclic anhydride, aliphatic anhydride, polyamide resin, linear phenolic aldehyde resin and polyphenol resin, arylamine formaldehyde resin, polysulfide compound, polyester resin, latent curing agent, flame-retardant curing agent and active ester curing agent.

[0024] Preferably, the epoxy curing agent is selected from one or more of dicyandiamide, polyamide, linear phenolic aldehyde resin and aromatic diamine curing agent.

[0025] Preferably, the reaction temperature of the component (b) epoxy curing agent and epoxy resin is above 100℃, so as to ensure that the epoxy resin and epoxy curing agent react as little as possible in the pre-reaction stage and react more in the subsequent semi-curing or curing process. The epoxy curing agent can be dicyandiamide, linear phenolic aldehyde resin, aromatic amine and the like. If the low-flow prepreg has high heat resistance requirement, then the curing agent is preferably aromatic amine, linear phenolic aldehyde resin and aromatic anhydride; if the low-flow prepreg has low dielectric property requirement, then the curing agent is preferably active ester or anhydride.

[0026] Preferably, the curing accelerator is selected from one or more of imidazole accelerator, amine accelerator, tin accelerator and DBN / DBU. The DBN / DBU respectively refers to 1,8-diazabicyclo-dicyclo(5,4,0)-7-undecene (DBU) and 1,5-diazabicyclo(4,3,0) non-5-ene (DBN).

[0027] The imidazole accelerator can be 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole and the like. The amine accelerator can be triethylenediamine, N-amino morpholine, boron trifluoride ethylamine and the like. The tin accelerator can be dibutyltin dilaurate, stannous octoate and the like.

[0028] Preferably, the oxazoline compound has the following structure in the structural formula:

[0029] R-(Ox)n,

[0030] wherein Ox is oxazoline ring or substituted oxazoline ring, R is alkylene, cycloalkylene, arylene, polyarylene, heteroarylene or polyheteroarylene, and n is a positive integer greater than or equal to 2. The oxazoline compound can also be a modified oxazoline compound.

[0031] The oxazoline compound of component (e) can be 1,2-bis(2-oxazoline-2)ethane, 1,4-bis(2-oxazoline-2)butane, 1,6-bis(2-oxazoline-2)hexane, 1,8-bis(2-oxazoline-2)octane, or 1,4-bis(2-oxazoline-2)cyclohexane; and such compounds wherein the two oxazoline rings have been bonded to an aromatic moiety, such as, for example, 1,2-bis(2-oxazolinyl-2)benzene, 1,3-bis(2-oxazolinyl-2)benzene, 1,4-bis(2-oxazolinyl-2)benzene, 5,5'-dimethyl-2,2'-bis(2-oxazolinyl-2)benzene, 4,4,4',4'-tetramethyl-2,2'-bis(2-oxazolinyl-2)benzene, 1,2-bis(5-methyl-2-oxazolinyl-2)benzene, 1,3-bis(5-methyl-2-oxazolinyl-2)benzene, or 1,4-bis(5-methyl-2-oxazolinyl-2)benzene; or 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(5-methyl-2-oxazoline), and the like.

[0032] More preferably, the oxazoline compound is added in an amount of 40-90% of component (d); it can also be 35%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 95%. Better adhesive strength and apparent flatness can be obtained.

[0033] Preferably, the resin composition further comprises component (f): a filler selected from one or several of crystalline silica, fused silica, spherical silica, aluminum oxide, aluminum hydroxide, aluminum nitride, boron nitride, titanium dioxide, strontium titanate, barium titanate, barium sulfate, talc, calcium silicate, calcium carbonate, mica, polytetrafluoroethylene, graphene;

[0034] The filler is added in an amount of 5-80% of the total amount of the resin composition. More preferably, 7-20%. It can also be 10%, 15%, 20%, 25%, 30%, 40%, 45%, 55%, 60%, 65%, 70%, 75%.

[0035] In the above, the filler is added in an amount of 5-80% of the total amount of the resin composition, specifically, in terms of weight parts, relative to 100 parts by weight of the total resin composition, the filler is added in an amount of 5-80 parts by weight. The filler can be surface treated with a silane coupling agent, can be directly put into or prepared into a filler dispersion or paste into the resin composition; the particle size of the filler is preferably 0.5-10 microns.

[0036] The resin composition can further comprise a flame retardant, other toughening agent, heat resistance modifier, etc. according to actual needs.

[0037] The present application also claims a prepreg with low flow adhesive made of the resin composition described above, the resin composition is dissolved in a solvent to form a glue solution, then the reinforcing material is immersed in the glue solution, and the low flow adhesive prepreg is obtained after the reinforcing material is dried by heating.

[0038] The organic solvent in the present application is not specifically limited. For example, the organic solvent can be selected from one or a combination of any of acetone, butanone, toluene, methyl isobutyl ketone, N, N-dimethylformamide, N, N-dimethylacetamide, ethylene glycol methyl ether, propylene glycol methyl ether, benzene, toluene, xylene, cyclohexane. The reinforcing material is a natural fiber, an organic synthetic fiber, an organic fabric, or an inorganic fabric; preferably, the reinforcing material is a glass fiber cloth, and preferably an open fiber cloth or a flat cloth is used in the glass fiber cloth. In addition, when the reinforcing material is a glass fiber cloth, the glass fiber cloth generally needs to be chemically treated to improve the interfacial bonding between the resin composition and the glass fiber cloth. The main method of chemical treatment is coupling agent treatment. The coupling agent used is preferably an epoxy silane or an amino silane, etc., to provide good water resistance and heat resistance.

[0039] The specific preparation method of the prepreg is as follows: the resin composition is added to a glue mixing kettle, a diluent is added to adjust the solid content to 40-70%, and the glue solution is obtained after uniform stirring, then the reinforcing material is immersed in the glue solution, and the low flow adhesive prepreg provided by the present application is obtained after the reinforcing material is dried by baking at 100-200°C for 3-10 min.

[0040] The present application also claims a rigid-flexible combined printed circuit board comprising the low flow adhesive prepreg described above.

[0041] Due to the use of the above technical solutions, the present application has the following advantages compared with the prior art:

[0042] 1. The present application develops a new low flow adhesive prepreg which has excellent toughness and low powder loss rate, significantly improves the adhesion and the apparent flatness of the low flow adhesive prepreg, and finally obtains a low flow adhesive prepreg with excellent comprehensive performance of glue overflow amount, toughness / powder loss rate, interlayer adhesion of bonded sheets, apparent flatness of bonded sheets, heat resistance, etc., which can be well used in rigid-flexible combined printed circuit boards.

[0043] 2. In the process of preparing the resin composition, the components (a) epoxy resin, (b) epoxy resin curing agent, (d) carboxyl nitrile rubber, (e) oxazoline compound are pre-reacted, the reaction speed and progress are controlled by controlling the pre-reaction temperature and time, and then the curing accelerator is added, so as to control the reaction process, so that the carboxyl nitrile rubber is inside the polymer after polymerization, that is, it can play a role in toughening and reducing the powder loss rate, and greatly reduce the amount of carboxyl nitrile rubber, thereby improving the bonding performance and apparent flatness, and finally obtaining a low flow semi-cured sheet with excellent comprehensive performance;

[0044] 3. The preparation process of the present application is simple and easy to operate, and the cost is low, which is suitable for popularization and application. DETAILED DESCRIPTION

[0045] The present application will be further described below in combination with examples:

[0046] The formulations of examples 1-6 and comparative examples 1-6 are shown in the following Tables 1 and 2; the preparation method is as follows:

[0047] S1, the dissolved components (a) epoxy resin, (b) epoxy resin curing agent, (d) carboxyl nitrile rubber, (e) oxazoline compound are mixed according to the proportion to prepare a resin mixture;

[0048] S2, the above resin mixture is pre-reacted at a temperature of 50-100℃ for 2-30 hours; to obtain a pre-reaction product;

[0049] S3, the dissolved component (c) curing accelerator is added to the above pre-reaction product, and stirred and mixed uniformly to prepare the resin composition;

[0050] The above component (a) corresponds to A1 to A4 in the following table; component (b) corresponds to B1 to B2 in the following table; component (c) corresponds to C in the following table; component (e) corresponds to E1 to E2 in the following table;

[0051] Then, a 55% resin solution is prepared according to the specified pre-reaction conditions, electronic grade 2116 glass cloth is used as the reinforcing material to impregnate the above resin solution, and then the prepreg is heated and cured in an oven for a certain time to obtain a low flow semi-cured sheet. Part of the semi-cured sheet is pressed into a laminated sheet according to the following conditions, and then the properties of the semi-cured sheet and the laminated sheet are evaluated by the following methods.

[0052] The formulation of Comparative Example 7 is shown in Table 2 below; the resin composition of Comparative Example 7 was prepared according to the following steps: first, components (d) carboxyl nitrile rubber and (e) oxazoline compound were mixed in the ratio, and pre-reaction was carried out according to the pre-reaction conditions in Table 2; second, the pre-reaction compound obtained in the first step was mixed with dissolved (a) epoxy resin, (b) epoxy resin curing agent and (c) curing accelerator to obtain a uniform mixture; a 55% resin solution was prepared, and electronic-grade 2116 glass fiber cloth was used as a reinforcing material to impregnate the resin solution, and then the prepreg was heated and cured in an oven for a certain period of time to obtain a low-flow adhesive prepreg. Part of the prepreg was pressed into a laminate according to the following conditions, and then the performance of the prepreg and the laminate was evaluated by the following methods.

[0053] Prepreg impregnation conditions of the low-flow adhesive prepreg: 165℃ / 3-5min;

[0054] Laminate panel parameters: the structure was 5*2116, and the thickness of the panel after molding was 0.6mm; the panel curing conditions were 190℃ / 2h;

[0055] Prepreg test items: excess adhesive amount, cutting edge quality, and powder loss rate.

[0056] Excess adhesive amount determination: PP was made into a square sample of 100mm*100mm, and a 1-inch circular hole was punched in the middle position. Then, the PP sample was stacked according to the order of "steel plate + copper-clad plate + PP sample + release film + buffer material + steel plate", and pressed using a press with set temperature / pressure / time. After pressing, the excess adhesive amount at the circular hole position of the sample was taken out to evaluate the adhesive flow size under hot pressing conditions.

[0057] Cutting edge quality determination: the prepreg was cut with a sampler for resin content testing, and the cut sample was observed under a 10x magnifying lens to determine the degree of edge whitening. The more obvious the whitening, the more resin powder was shed. In order to facilitate evaluation, the cutting edge quality was represented by the number of stars, with five stars indicating excellent cutting edge quality and one star indicating poor cutting edge quality.

[0058] Toughness (powder loss rate) determination: the degree of resin powder shedding after cutting / shearing treatment of the prepreg was used as the basis for judgment. The specific test method was as follows: four 10cm*10cm pieces of prepreg were taken, weighed and recorded as m1. A 9cm deep notch was cut on one side of each piece using scissors, and a total of 29 cuts were made on each piece to form 30 small strips of 9cm long. The treated sample was held with the wrist as the center and shaken up and down 30 times, which was counted as one vibration. After completion, the sample was weighed again and recorded as m2. The powder loss rate of the prepreg was calculated as (m1-m2) / m1*100%.

[0059] Prepreg appearance defect: The appearance of the prepreg was observed.

[0060] Prepreg interlaminar adhesion strength: After two low-tack prepregs were pressed together and completely cured, the interlaminar adhesion strength of the low-tack prepreg was tested using a universal material testing machine at 90° peeling.

[0061] Sheet glass transition temperature Tg: The glass transition temperature Tg of the sheet was determined according to the differential scanning calorimetry method specified in IPC-TM-650 2.4.25.

[0062] Table 1: Examples

[0063]

[0064] Table 2: Comparative Examples

[0065]

[0066] Notes to Table 1 and Table 2:

[0067] A1: Phosphorus-modified epoxy resin, epoxy equivalent weight 265 g / eq, Dongcaistechnology;

[0068] A2: Bisphenol A epoxy resin, epoxy equivalent weight 185 g / eq, Guodu Chemical;

[0069] A3: Bisphenol A novolac epoxy resin, epoxy equivalent weight 205 g / eq, Shengquan New Material;

[0070] A4: UV resin, epoxy equivalent weight 210 g / eq, Dongcaistechnology;

[0071] B1: Dicy, dicyandiamide, Ningxia Darong;

[0072] B2: DDS, diamino diphenyl sulfone, Hebei Jianxing;

[0073] C: 2-Ethyl-4-methylimidazole;

[0074] D: Carboxyl nitrile rubber, Nipol 1072, Japan Zeon;

[0075] E1: Oxazoline compound, 1,3-phenylene bisoxazoline, domestic reagent;

[0076] E2: Oxazoline compound, oxazoline group-containing polymer, imported from Japan;

[0077] F: Filler, DQ1028L, Jiangsu Lianrui;

[0078] From the results of Table 1 and Table 2, it can be seen that: compared with Comparative Example 1, Comparative Example 2, Comparative Example 4, Comparative Example 6, Comparative Example 7, the prepreg of Example 1 has obviously higher interlaminar bonding strength. Compared with Comparative Example 3, Comparative Example 5, Comparative Example 7, the prepreg of Example 1 has obviously better appearance and higher interlaminar bonding strength.

[0079] Compared with Comparative Example 1-7, the prepregs of Example 1-6 have higher interlaminar bonding strength, better appearance flatness and excellent comprehensive performance while ensuring that the low-flow prepreg has excellent toughness and low powder shedding rate.

[0080] Compared with Example 3-4, the prepregs of Example 1-2 have obviously higher interlaminar bonding strength.

[0081] In summary, the resin composition of the present application and the low-flow prepreg prepared by using the resin composition have low-flow characteristics, excellent toughness, good edge quality of the prepreg after mechanical cutting, less resin powder shedding, obviously improved appearance of the low-flow prepreg, and excellent interlaminar bonding strength of the prepreg. Under the premise of ensuring good toughness and low powder shedding rate of the low-flow prepreg, the problem of the decrease of the bonding performance of the low-flow prepreg caused by excessive addition of the rubber component is solved, and the problem of the appearance flatness of the prepreg is also solved.

[0082] The above description of the disclosed embodiments allows a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A resin composition, characterized by comprising: The resin composition comprises the following components by weight parts: (a) epoxy resin, 100 parts; (b) epoxy curing agent, 2-100 parts; (c) curing accelerator, 0.05-1 parts; (d) carboxyl nitrile rubber, 1-10% of the total amount of components (a), (b) and (c); (e) oxazoline compound, the addition amount of the oxazoline compound is 30-100% of component (d); The preparation method of the resin composition is as follows: S1, the dissolved components (a) epoxy resin, (b) epoxy resin curing agent, (d) carboxyl nitrile rubber, (e) oxazoline compound are mixed according to the proportion to prepare a resin mixture; S2, the above resin mixture is pre-reacted at a temperature of 50-100°C for 2-30 hours to obtain a pre-reactant; S3, the dissolved component (c) curing accelerator is added to the above pre-reactant and stirred to obtain the resin composition.

2. The resin composition according to claim 1, characterized by The epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, tetraphenyl ethane epoxy resin, triphenyl methane epoxy resin, biphenyl type epoxy resin, naphthalene ring type epoxy resin, dicyclopentadiene type epoxy resin, isocyanate type epoxy resin, aralkyl linear phenolic aldehyde epoxy resin, bisphenol A aldehyde type epoxy resin, polyphenyl ether modified epoxy resin, alicyclic epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin.

3. The resin composition according to claim 1, characterized by The epoxy curing agent is selected from one or more of aliphatic amine, aromatic amine, alicyclic amine, heterocyclic amine, aromatic anhydride, alicyclic anhydride, aliphatic anhydride, polyamide resin, linear phenolic aldehyde resin and polyphenol resin, aromatic amine formaldehyde resin, polysulfide compound, polyester resin, latent curing agent, flame-retardant curing agent, active ester curing agent.

4. The resin composition according to claim 3, characterized by The epoxy curing agent is selected from one or more of dicyandiamide, polyamide, linear phenolic aldehyde resin, aromatic diamine curing agent.

5. The resin composition according to claim 1, characterized by The curing accelerator is selected from one or more of imidazole accelerator, amine accelerator, tin accelerator, DBN / DBU.

6. The resin composition according to claim 1, characterized by The oxazoline compound has the following structure in its structural formula: R-(Ox)n, Wherein, Ox is an oxazoline ring or a substituted oxazoline ring, R is an alkylene group, a cycloalkylene group, an arylene group, a polyarylene group, a heteroarylene group or a polyheteroarylene group, and n is a positive integer greater than or equal to 2.

7. The resin composition according to claim 1, characterized by The addition amount of the oxazoline compound is 30-100% of component (d).

8. The resin composition according to claim 1, characterized by The resin composition further comprises component (f): filler, which is selected from one or more of crystalline silica, fused silica, spherical silica, aluminum oxide, aluminum hydroxide, aluminum nitride, boron nitride, titanium dioxide, strontium titanate, barium titanate, barium sulfate, talc, calcium silicate, calcium carbonate, mica, polytetrafluoroethylene, graphene; The addition amount of the filler is 5-80% of the total amount of the resin composition.

9. A low flow prepreg made using the resin composition according to any one of claims 1 to 8, characterized by: The resin composition is dissolved with a solvent to prepare a glue solution, then the reinforcing material is immersed in the above glue solution, and after heating and drying the immersed reinforcing material, the low-flow glue prepreg is obtained.

10. A rigid-flex printed circuit board, characterized by: A prepreg containing the low-flow prepreg according to claim 9.

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