Halogen-free flame-retardant resin composition, prepreg, laminated board and printed circuit board

Abstract

The invention provides a halogen-free flame-retardant resin composition, a prepreg, a laminated board and a printed circuit board, the halogen-free flame-retardant resin composition comprises the following components in parts by weight: 100 parts of thermosetting resin and 10-50 parts of a Di-DOPO flame retardant with a melting point greater than 280 DEG C, and the halogen-free flame-retardant resin composition does not contain the Di-DOPO flame retardant with a melting point lower than 280 DEG C. When a board prepared from the resin composition is subjected to a high temperature of 250 DEG C or above in a component welding process, a flame retardant cannot be separated out and migrated to the surface of the board to cause surface pollution, so that a reliability fault between a PCB (Printed Circuit Board) and a component cannot be caused, and meanwhile, the board has excellent dielectric property and flame retardant property.

Description

Technical Field

[0001] This invention belongs to the field of laminate technology and relates to a halogen-free flame-retardant resin composition, prepreg, laminate, and printed circuit board. Background Technology

[0002] With the advent of the 5G era, data switches, routers, high-end servers, and other devices are facing increasingly higher demands for data volume and transmission speed, which in turn places higher requirements on the dielectric properties of circuit boards. Di-DOPO flame retardant is one of the halogen-free flame retardants with the best dielectric properties currently available in the industry.

[0003] During the component soldering process, PCBs are exposed to temperatures above 250°C. At 240°C, some components of conventional DOPO flame retardant will melt and migrate to the PCB surface, causing surface contamination and leading to reliability failures between the PCB and components.

[0004] CN 109180734A discloses a method for converting DOPO derivative isomers. This method involves adding an aqueous solution of a heteropoly acid to a mixture containing low-melting-point isomers, which can convert the low-melting-point isomers into higher-melting-point isomers with greater application value, thus improving their performance as flame retardants. However, the method does not test the melting point, and the invention only mentions its use in epoxy resin systems, failing to demonstrate the dielectric properties of the flame retardant.

[0005] CN102971333A discloses a composition in which the high-melting-point isomer of DOPO derivative accounts for more than 95%, but its melting point does not fully meet the requirements for avoiding contamination in PCB processing. The DSC testing method in this invention involves testing from 0℃ to 400℃ at a rate of 10℃ / min in a gold-plated stainless steel crucible. However, in actual testing, the results were found to fluctuate significantly, making it difficult to stably characterize the proportion of high and low melting-point isomers.

[0006] Therefore, in this field, there is a desire to develop a material that can solve the problem of high-temperature flame retardant release. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a halogen-free flame retardant resin composition, prepreg, laminate, and printed circuit board.

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

[0009] On one hand, the present invention provides a halogen-free flame retardant resin composition comprising the following components in parts by weight: 100 parts of thermosetting resin and 10-50 parts of Di-DOPO flame retardant with a melting point greater than 280°C, and wherein the halogen-free flame retardant resin composition does not contain Di-DOPO flame retardant with a melting point lower than 280°C.

[0010] Commercially available Di-DOPO flame retardants are mixtures of high-melting-point isomers and low-melting-point isomers, including a high-melting-point isomer with formula IIa, a low-melting-point isomer with formula IIb, and a low-melting-point isomer with formula IIc.

[0011]

[0012] For example, the DSC curve of Albemarle XP7866 shows that the area of ​​the low melting endothermic peak at 245℃ accounts for 9%, and the area of ​​the melting endothermic peak at 294℃ accounts for 91% (heating rate of 200-300℃ is 2.5℃ / min), indicating that it contains both high-melting-point isomers and low-melting-point isomers. In this invention, by selecting a Di-DOPO flame retardant with a melting point greater than 280℃ in the halogen-free flame-retardant resin composition, and not containing any Di-DOPO flame retardant with a melting point lower than 280℃ (that is, all isomers in the Di-DOPO flame retardant have melting points greater than 280℃, and there are no Di-DOPO isomers with melting points lower than 280℃), the board prepared by this resin composition can withstand temperatures above 250℃ during component soldering without the flame retardant precipitating and migrating to the board surface and causing surface contamination. Therefore, it will not lead to reliability failures between the PCB and components, and at the same time, it has excellent dielectric and flame-retardant properties.

[0013] It should be noted that the proportion of high-melting-point isomers in the Di-DOPO flame retardant of this invention is calculated using DSC curves: At a heating rate of 5°C / min between 200-300°C, the areas of peaks with melting points greater than 280°C and peaks with melting points less than 280°C in the DSC curves are calculated. The proportion of high-melting-point isomers = A h / (A h +A l ), where A h Area of ​​the high melting point peak, A l The area of ​​the low melting point peak. This invention refers to the absence of Di-DOPO flame retardants with melting points below 280℃, meaning that no peaks with melting points below 280℃ appear when tested using DSC curves. Alternatively, the method mentioned in CN102971333A can also be used. 31 The isomer ratios corrected by the PNMR method are basically consistent between the two.

[0014] In this invention, the Di-DOPO flame retardant with a melting point greater than 280°C can have melting points of 285°C, 288°C, 290°C, 295°C, 298°C, 300°C, etc.

[0015] In this invention, the content of Di-DOPO flame retardant with a melting point greater than 280°C in the halogen-free flame retardant resin composition can be 10 parts by weight, 15 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, or 50 parts by weight. If the content of Di-DOPO flame retardant with a melting point greater than 280°C in the halogen-free flame retardant resin composition is less than 10 parts by weight, the flame retardant effect is lacking, resulting in insufficient flame retardancy. However, DI-DOPO is an insoluble and infusible flame retardant used in copper-clad laminate processing, and its structure is relatively loose. If the content is higher than 50 parts by weight, it will reduce the adhesion of the board, resulting in insufficient toughness and poor reliability.

[0016] If the halogen-free flame-retardant resin composition of the present invention contains a DI-DOPO flame retardant with a melting point below 280°C, the flame retardant will precipitate when the resin composition is prepared into a board and subjected to high-temperature reflow soldering above 250°C during the component soldering process, forming crystals or other forms of contamination on the surface of the circuit board.

[0017] Preferably, the structural formula of the Di-DOPO flame retardant is as follows:

[0018] .

[0019] Preferably, the thermosetting resin is selected from any one or a combination of at least two of the following: polyphenylene ether, polybutadiene (including functionalized polybutadiene), butadiene-styrene copolymer, polyvinylbenzene, divinylbenzene-styrene copolymer, bismaleimide, cyanate ester, benzocyclobutene-containing oligomers, alkynyl-containing compounds, triallyl isocyanurate, triallyl cyanurate, silicone resin, or compounds having two or more olefin groups. More preferably, it is selected from any one or a combination of at least two of the following: polyphenylene ether, polybutadiene, polyvinylbenzene, divinylbenzene-styrene copolymer, or compounds having two or more olefin groups. These preferred resin components have relatively lower dielectric loss, which better meets the requirements of high-speed signal transmission.

[0020] Preferably, the halogen-free flame retardant resin composition further includes an initiator.

[0021] Preferably, the initiator is selected from any one or a combination of at least two of the following: peroxide initiator, metal salt of acetylacetone, metal salt of naphthenic acid, vanadium pentoxide, amine compound (e.g., aniline), quaternary ammonium salt, imidazole, or triphenylphosphine.

[0022] Preferably, the peroxide initiator is selected from any one or a combination of at least two of the following: dicumyl peroxide, tert-butyl peroxide, di-tert-butyl peroxide, tert-butyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-di-tert-butylcumyl peroxyhexyn-3, 2,5-dimethyl-2,5-di-tert-butyl peroxide, p-menthol peroxide, 1,1-bis(tert-amylperoxy)cyclohexane, diisopropylbenzene hydrogen peroxide, benzoyl peroxide, or benzoyl peroxide.

[0023] In this invention, the purpose of the initiator is to accelerate the curing and crosslinking of the thermosetting resin components. The optimal curing effect is to be able to initiate the crosslinking reaction of the resin components between 100-200°C, so as to obtain a high heat-resistant resin material with stable mechanical properties below 200°C and no decomposition or significant deformation below 300°C.

[0024] Preferably, the amount of the initiator is 0.01-1 part, such as 0.01 part, 0.1 part, 0.2 part, 0.3 part, 0.5 part, 0.8 part or 1 part, and more preferably 0.05-0.5 parts.

[0025] Preferably, the halogen-free flame-retardant resin composition further includes inorganic fillers.

[0026] Preferably, the inorganic packing includes any one or a combination of at least two of spherical packing, angular packing, or sheet packing.

[0027] Preferably, the inorganic packing contains ≥10% by mass of spherical packing, such as 10%, 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc.

[0028] Preferably, the inorganic filler comprises any one or a combination of at least two of the following: silicon dioxide, silica powder, alumina, titanium dioxide, mica, silica, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay, talc, aluminum borate, silicon carbide, or beryllium oxide.

[0029] Preferably, the inorganic filler contains ≥30% silica by mass, for example, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc.

[0030] Preferably, the amount of the inorganic filler is 20 to 100 parts, such as 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 80 parts or 100 parts, and more preferably 25 to 67 parts.

[0031] To better ensure the flame retardant properties of the resin composition, preferably, the halogen-free flame retardant resin composition may also include other flame retardants, which are selected from any one or a combination of at least two of nitrogen-containing phosphate flame retardants, phosphazene flame retardants, or 2,6-bis(2,6-dimethylphenyl)phosphonobenzene.

[0032] Preferably, the nitrogen-containing phosphate flame retardant is selected from any one or a combination of at least two of melamine phosphate, melamine polyphosphate, or dimelamine pyrophosphate.

[0033] Preferably, the phosphazene flame retardant is selected from any one or at least a combination of two of hexachlorocyclotriphosphazene, alkoxycyclotriphosphazene, phenoxycyclotriphosphazene, hexaaminocyclotriphosphazene, or aryloxy-substituted polyphosphazene.

[0034] The study found that when nitrogen-containing flame retardants are combined with the Di-DOPO flame retardant described in this invention, the flame retardant effect is better and the burning time is shorter.

[0035] Preferably, the amount of the other flame retardant is 5-40 parts, such as 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts or 35 parts.

[0036] Preferably, the halogen-free flame-retardant resin composition further includes a silane coupling agent.

[0037] Studies have found that adding a certain amount of silane coupling agent to the halogen-free resin composition described in this invention can improve the toughness of the resin composition and enhance the bonding strength between the resin composition and fiberglass reinforcement materials, copper foil, etc.

[0038] In this invention, the type of silane coupling agent is related to the type of thermosetting resin component. It has been found that aniline silane coupling agents, vinyl silane coupling agents, propylene silane coupling agents, isobutylene silane coupling agents, styrene silane coupling agents, methyl silane coupling agents, or phenyl silane coupling agents have better effects. Silane coupling agents containing epoxy or amino groups can negatively impact the resin composition by reducing heat resistance, toughness, and adhesion to copper foil; therefore, their use is not recommended.

[0039] Preferably, the amount of the silane coupling agent is 0.1%-2% of the filler, for example 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 1.8% or 2%.

[0040] On the other hand, the present invention provides a resin adhesive solution, which is obtained by dissolving or dispersing the resin composition described above in a solvent.

[0041] On the other hand, the present invention provides a prepreg comprising a reinforcing material and a resin composition as described above, which is attached to the reinforcing material after impregnation and drying.

[0042] The reinforcing material includes any one or a combination of glass fiber cloth, organic fiber cloth, and glass fiber nonwoven fabric.

[0043] Preferably, the proportion of alkali metals in the glass fibers of the glass fiber cloth or glass fiber nonwoven fabric is less than 0.1% (e.g., 0.09%, 0.08%, 0.06%, 0.04%, 0.02%, etc.), and the proportion of Ca element is less than 10% (e.g., 8%, 6%, 4%, 2%, 1%, etc.). This results in a laminate with superior dielectric properties.

[0044] Preferably, the organic fibers used in the organic fiber cloth have a glass transition temperature greater than 200°C, such as 220°C, 250°C, 300°C, 350°C, 400°C, etc.

[0045] On the other hand, the present invention provides a laminate comprising at least one prepreg as described above.

[0046] On the other hand, the present invention provides a metal foil laminate, the metal foil laminate comprising at least one prepreg as described above and metal foils covering both sides of the laminated prepreg.

[0047] On the other hand, the present invention provides a printed circuit board, the printed circuit board comprising the prepreg as described above, or the laminate as described above, or the metal foil laminate as described above.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] In this invention, by using a DI-DOPO flame retardant with a melting point greater than 280°C in the halogen-free flame retardant resin composition, and without containing a DI-DOPO flame retardant with a melting point lower than 280°C, the board prepared by the resin composition can withstand high temperatures above 250°C during component soldering without the flame retardant precipitating and migrating to the board surface and causing surface contamination. Therefore, it will not lead to reliability failures between the PCB and the components, and at the same time has excellent dielectric and flame retardant properties. Attached Figure Description

[0050] Figure 1 The DSC test results of flame retardant sample P1 prepared in Example 1 are shown in the figure.

[0051] Figure 2 The DSC test results of flame retardant sample P2 prepared in Preparation Example 1 are shown for comparison.

[0052] Figure 3 The image shows the DSC test results for XP7866.

[0053] Figure 4 The image shows the "oil stains" phenomenon on the board surface caused by precipitation after reflow soldering in Comparative Example 2 (both images show oil stains seeping from the board surface). Detailed Implementation

[0054] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0055] Preparation Example 1

[0056] The DSC test results of Di-DOPO flame retardant (XP7866) are shown in the figure below. Figure 3 As shown, 80g of a 245℃ melting point sample (9% of which has a high melting point peak at 294℃) was mixed with 10g of 85% phosphoric acid aqueous solution and 400g of diphenylpropane. The mixture was stirred and heated to 200℃, kept at that temperature for 3 hours, and then cooled to room temperature before filtration. The filtrate was washed twice with 1000mL of acetone, filtered again, and dried at 100℃ for 1 hour to obtain flame retardant sample P1. The DSC test results are shown below. Figure 1 As shown, it has no melting point endothermic peak below 280℃, and the melting point endothermic peak is 298℃.

[0057] Comparative Preparation Example 1

[0058] 80g of Di-DOPO flame retardant (XP7866, 9% melting point at 245℃, 91% high melting point peak at 294℃), 10g of 85% phosphoric acid aqueous solution, and 400g of diphenylpropane were mixed, stirred, and heated to 200℃. After holding at this temperature for 1 hour, the mixture was cooled to room temperature and filtered. The filtrate was washed twice with 1000ml of acetone, filtered again, and dried at 100℃ for 1 hour to obtain flame retardant sample P2. The DSC test results are as follows: Figure 2 As shown, its melting point at 245℃ accounts for 4%, and its high melting point endothermic peak is 294℃.

[0059] The source information of the raw materials used in the examples and comparative examples is as follows:

[0060] XP7866: Di-DOPO flame retardant, Albemarle;

[0061] SA9000: Functionalized polyphenylene ether, SABIC;

[0062] B-1000: Polybutadiene resin, Nippon Soda;

[0063] Ricon257: A copolymer of butadiene, divinylbenzene and styrene, Clayville;

[0064] Ricacryl 3500: Functionalized polybutadiene resin, Krevili;

[0065] TAIC: Triallyl isocyanurate, Evonik;

[0066] DVB: Divinylbenzene, Nippon Steel;

[0067] NQ2030: Spherical silica powder, Jiangsu Lianrui;

[0068] Nonfla 601: Melamine polyphosphate, Douben Company;

[0069] Z-6030: Allyl silane coupling agent, Shin-Etsu Chemical Co., Ltd., Japan;

[0070] DCP: Dicumyl peroxide, Nourion;

[0071] Toluene: a solvent, commercially available;

[0072] BMI-70: Bismaleimide resin, KI (Japan);

[0073] MEK: Solvent, butanone, commercially available.

[0074] Example

[0075] The compositions of the halogen-free flame retardant resin compositions provided in Examples 1-10 and Comparative Examples 1-4 are shown in Tables 1 and 2 (where the amount of each component is in parts by weight).

[0076] The components of the halogen-free flame-retardant resin composition are dissolved in a solvent to obtain a resin solution with a solid content of about 68%.

[0077] A low-Dk glass fiber cloth of model 2116 is uniformly impregnated with the above-mentioned resin solution and baked in a forced-air oven at 155°C for 3 minutes to obtain a prepreg sheet (i.e., prepreg material). Four of the above-mentioned prepreg sheets are overlapped, covered with 35μm copper foil on the top and bottom, and pressed in a vacuum hot press at 3MPa pressure and 210°C for 90 minutes to obtain a laminate.

[0078] Performance testing of the laminate:

[0079] (1) Glass transition temperature Tg: Tested using dynamic thermomechanical analysis (DMA), referring to the DMA test method specified in IPC-TM-650 2.4.24.

[0080] (2) Flame resistance: Tested according to UL94 "50W (20mm) Vertical burning test: V-0, V-1 and V-2" test method, V-0 is identified as flame retardant. The sum of burning times refers to the sum of burning times t1 and t2.

[0081] (3) Reliability of the laminate after five reflow solderings: The copper-free laminate is reflow soldered five times. The surface temperature of the laminate is above 250°C for 30-50 seconds during each reflow soldering, and the highest temperature reaches 260°C. Observe whether the laminate delamination or blistering occurs.

[0082] (4) Flame retardant precipitation on the board surface after five reflow soldering: The copper-free laminate is reflow soldered five times. The surface temperature of the laminate is above 250℃ for 30-50s during each reflow soldering, and the highest temperature reaches 260℃. Observe whether there is any surface abnormality caused by flame retardant precipitation on the laminate surface.

[0083] The test results are detailed in Tables 1 and 2.

[0084] Table 1

[0085]

[0086] Table 2

[0087]

[0088] As shown in Table 1, the laminate samples from the embodiments exhibited no delamination or blistering after reflow soldering, with clean and tidy surfaces and no flame retardant precipitation. However, Comparative Examples 1 and 2 showed "oil stains" on the surface after precipitation following reflow soldering. The amount of flame retardant in Comparative Example 3 was too small, resulting in a total burning time exceeding 50 seconds, failing to achieve V-0 flame retardancy. The amount of flame retardant in Comparative Example 4 was too large, leading to delamination after five reflow soldering cycles and poor heat resistance reliability.

[0089] The applicant declares that the present invention is illustrated through the above embodiments to demonstrate the halogen-free flame-retardant resin composition, prepreg, laminate, and printed circuit board of the present invention. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A halogen-free flame-retardant resin composition, characterized by comprising: The halogen-free flame-retardant resin composition comprises the following components by weight: 100 parts of a thermosetting resin and 10-50 parts of a Di-DOPO flame retardant with a melting point greater than 280℃, and the halogen-free flame-retardant resin composition does not contain Di-DOPO flame retardants with a melting point lower than 280℃.

2. The halogen-free flame-retardant resin composition according to claim 1, characterized by, The structural formula of the Di-DOPO flame retardant is as follows: 。 3. The halogen-free flame-retardant resin composition according to claim 1 or 2, characterized by, The thermosetting resin is selected from any one or a combination of at least two of polyphenylene ether, polybutadiene, butadiene-styrene copolymer, polydivinylbenzene, divinylbenzene-styrene copolymer, bismaleimide, cyanate ester, oligomer containing benzocyclobutene, alkyne-containing compound, triallyl isocyanurate, triallyl cyanurate, silicone resin, or compound having two or more olefin groups; further preferably, any one or a combination of at least two of polyphenylene ether, polybutadiene, polydivinylbenzene, divinylbenzene-styrene copolymer, or compound having two or more olefin groups.

4. The halogen-free flame-retardant resin composition according to any one of claims 1 to 3, characterized in that, The halogen-free flame-retardant resin composition further comprises an initiator; Preferably, the initiator is selected from any one or a combination of at least two of peroxide initiator, metal salt of acetylacetone, metal salt of naphthenic acid, vanadium pentoxide, amine compound, quaternary ammonium salt, imidazole, or triphenylphosphine; Preferably, the peroxide initiator is selected from any one or a combination of at least two of dicumyl peroxide, tert-butyl peroxy cumyl, di-tert-butyl peroxide, tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-di-tert-butylcumylperoxy hexyne-3, 2,5-dimethyl 2,5-di-tert-butylperoxy hexane, p-menthane hydroperoxide, 1,1-bis(tert-amylperoxy)cyclohexane, diisopropylbenzene hydroperoxide, benzoyl peroxide, or benzoyl peroxide; Preferably, the initiator is used in an amount of 0.01-1 parts, preferably 0.05-0.5 parts; Preferably, the halogen-free flame-retardant resin composition further comprises an inorganic filler; Preferably, the inorganic filler comprises any one or a combination of at least two of spherical filler, angular filler, or flaky filler; Preferably, the mass percentage of the spherical filler in the inorganic filler is ≥10%; Preferably, the inorganic filler comprises any one or a combination of at least two of silicon dioxide, silicon powder, aluminum oxide, titanium dioxide, mica, silica, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay, talc, aluminum borate, silicon carbide, or beryllium oxide; Preferably, the mass percentage of silicon dioxide in the inorganic filler is ≥30%; Preferably, the inorganic filler is used in an amount of 20-100 parts, preferably 25-67 parts.

5. The halogen-free flame-retardant resin composition according to any one of claims 1 to 4, characterized in that, The halogen-free flame-retardant resin composition further comprises other flame retardants selected from any one or a combination of at least two of nitrogen-containing phosphate flame retardants, phosphazene type flame retardants, or 2,6-di(2,6-dimethylphenyl) phosphine phenyl. Preferably, the nitrogen-containing phosphate-based flame retardant is selected from any one or a combination of at least two of melamine phosphate, melamine polyphosphate or dimelamine pyrophosphate; Preferably, the phosphazene-based flame retardant is selected from any one or a combination of at least two of hexachlorocyclotriphosphazene, alkoxy cyclotriphosphazene, phenoxy cyclotriphosphazene, hexamino cyclotriphosphazene or aryloxy-substituted polyphosphazene; Preferably, the other flame retardant is used in an amount of 5-40 parts; Preferably, the halogen-free flame-retardant resin composition further comprises a silane coupling agent; Preferably, the silane coupling agent is selected from any one or a combination of at least two of aniline silane coupling agent, vinyl silane coupling agent, propylene silane coupling agent, isobutylene silane coupling agent, styrene silane coupling agent, methyl silane coupling agent or phenyl silane coupling agent.

6. A resin glue solution, characterized by, The resin glue solution is obtained by dissolving or dispersing the halogen-free resin composition of any one of claims 1-5 in a solvent.

7. A prepreg, characterized by, The prepreg comprises a reinforcing material and the resin composition of any one of claims 1-5 attached to the reinforcing material after impregnation and drying.

8. A laminate characterized by The laminate comprises at least one prepreg of claim 7.

9. A metal-clad laminate characterized by comprising: The metal-clad laminate comprises at least one prepreg of claim 7 and metal foils cladded on both sides of the prepreg after lamination.

10. A printed circuit board, characterized by The printed circuit board comprises the prepreg of claim 7 or the laminate of claim 8 or the metal-clad laminate of claim 9.

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