JP5587730B2 - Insulating resin composition, resin varnish, prepreg, metal-clad laminate, and printed wiring board - Google Patents

Description

  The present invention is obtained using an insulating resin composition suitably used for an insulating material of a printed wiring board, a resin varnish containing the insulating resin composition, a prepreg obtained using the resin varnish, and the prepreg. The present invention relates to a metal-clad laminate and a printed wiring board manufactured using the prepreg.

  2. Description of the Related Art In recent years, with various types of electronic equipment, mounting techniques such as higher integration of semiconductor devices to be mounted, higher density of wiring, and multilayering have rapidly progressed as the amount of information processing has increased. Insulating materials such as printed wiring boards used in various electronic devices are required to have low dielectric constant and dielectric loss tangent in order to increase signal transmission speed and reduce loss during signal transmission.

  Polyphenylene ether (hereinafter sometimes referred to as PPE) has excellent dielectric properties such as dielectric constant and dielectric loss tangent even in a high frequency band (high frequency region) from the MHz band to the GHz band. It is preferably used for an insulating material such as a printed wiring board of an electronic device to be used. However, since high molecular weight PPE generally has a high melting point, it tends to have high viscosity and low fluidity. In addition, when a printed wiring board is manufactured using a prepreg formed of PPE, there is a problem that a molding defect such as a void is generated at the time of multilayer molding, and it is difficult to obtain a highly reliable printed wiring board. It was.

  In order to solve such a problem, for example, a technique is known in which PPE is redistributed in a solvent in the presence of a phenol species and a radical initiator to perform molecular cleavage to lower the molecular weight of high molecular weight PPE. It has been. However, when the molecular weight of PPE is lowered, there is a problem that the curing becomes insufficient and the heat resistance of the cured product is lowered.

  Further, Patent Document 1 proposes an insulating resin composition using a monofunctional type PPE having an intrinsic viscosity of 0.15 dl / g. When such a PPE was used as a resin varnish, the viscosity of the varnish tended to increase remarkably as the PPE content ratio was increased, and the change with time was large. If a printed wiring board is manufactured using the prepreg formed with such an insulating resin composition, a molding defect will occur at the time of manufacture.

  Patent Document 2 proposes a composition that includes a polyarylene ether copolymer and an epoxy resin and that can further contain a flame retardant, and describes that curing at high temperatures can be improved. However, even the compositions described above may cause curing inhibition, and some of the compositions are not sufficiently excellent in dielectric properties and thermal properties.

US Pat. No. 6,352,782 International Publication No. 2008/033611

  The present invention has been made in view of the above-described problems of the prior art, and the problems to be solved are excellent dielectric properties and heat resistance of a cured product, low viscosity when made into a varnish, and high flame-retardant insulation. It aims at providing a resin composition. Also, a resin varnish containing the insulating resin composition, a prepreg obtained using the resin varnish, a metal-clad laminate obtained using the prepreg, and a printed wiring board using the metal-clad laminate The purpose is to provide.

  The inventors of the present invention have found that a polyarylene ether copolymer having a relatively low intrinsic viscosity and a relatively large number of phenolic hydroxyl groups at the molecular terminals, a brominated epoxy resin having high compatibility with toluene, and a phase of toluene. By combining with a highly soluble curing accelerator, it is possible to achieve both excellent dielectric properties and heat resistance, and to obtain an insulating resin composition having low flame resistance and high flame retardancy. The headline and the present invention were completed.

  Furthermore, it discovered that the specific brominated epoxy resin can suppress inhibition of the said three-dimensional bridge | crosslinking formation in the flame retardant contained in order to improve a flame retardance.

  Accordingly, the inventors have arrived at the present invention as described below from the above findings.

  The insulating resin composition according to the present invention has an intrinsic viscosity measured in methylene chloride at 25 ° C. of 0.03 to 0.12 dl / g, and an average of 1.5 to 1.5 phenolic hydroxyl groups per molecule terminal. A polyarylene ether copolymer (A) having three, a brominated epoxy resin (B) having a bromine content of 25 to 45% and a solubility in toluene of 10% by mass or more at 25 ° C., and a curing accelerator And (C).

  According to such a configuration, it is possible to obtain an insulating resin composition having excellent dielectric properties and heat resistance of a cured product, low viscosity when formed into a varnish, and high flame retardancy.

  This is considered to be due to the following.

  First, polyarylene ether copolymer having an intrinsic viscosity measured in methylene chloride at 25 ° C. of 0.03 to 0.12 dl / g and having an average of 1.5 to 3 phenolic hydroxyl groups per molecule at the molecular terminals. The compound (A) has a relatively low molecular weight and a relatively large number per molecule of phenolic hydroxyl groups at the molecular terminals, so it is considered that it easily forms a three-dimensional crosslink with the brominated epoxy resin (B). It is done.

  Further, since the brominated epoxy resin (B) has a solubility in toluene of 10% by mass or more at 25 ° C., the compatibility with the polyarylene ether copolymer (A) is relatively high. Therefore, it is considered that it is easy to uniformly react with the polyarylene ether copolymer (A) and easily form a three-dimensional crosslink.

  Therefore, it is considered that the three-dimensional crosslinking can be suitably advanced by using the polyarylene ether copolymer (A) and the brominated epoxy resin (B) in combination.

  Furthermore, the polyarylene ether copolymer (A) has a relatively low viscosity in solution of 0.03 to 0.12 dl / g measured in methylene chloride at 25 ° C., and the brominated epoxy Since the compatibility with the resin (B) is high, it is thought that the viscosity when a solvent is added to the obtained insulating resin composition to make a resin varnish becomes low.

  From the above, it is considered that the insulating resin composition has excellent dielectric properties and heat resistance of the cured product, has a low viscosity when formed into a varnish, and has high flame retardancy.

  Moreover, it is preferable that the said polyarylene ether copolymer (A) consists of at least any one of 2, 6- xylenol, bifunctional phenol, and trifunctional phenol. According to such a configuration, an insulating resin composition superior in dielectric properties and heat resistance of the cured product can be obtained. This is considered to be because the three-dimensional crosslinking can be suitably formed while maintaining the excellent dielectric properties of the PPE made of 2,6-dimethylphenol.

  In addition, the content of the polyarylene ether copolymer (A) is 45 to 75 with respect to 100 parts by mass of the total amount of the polyarylene ether copolymer (A) and the brominated epoxy resin (B). It is preferable that it is a mass part, and it is more preferable that it is 50-70 mass parts. According to such a configuration, an insulating resin composition that is excellent in dielectric properties and heat resistance of a cured product, has a low viscosity when formed into a varnish, and has high flame retardancy can be obtained.

  This is because the polyarylene ether copolymer (A) is contained in a relatively large amount, while maintaining the excellent dielectric properties of the polyarylene ether copolymer (A). This is considered to be due to being able to be suitably formed.

  Moreover, the resin varnish concerning this invention contains the said insulating resin composition and a solvent. According to such a configuration, a resin varnish having excellent dielectric characteristics, heat resistance of a cured product, and flame retardancy, low viscosity, and high fluidity can be obtained. And the prepreg obtained using this resin varnish can manufacture electronic components, such as a printed wiring board, suppressing generation | occurrence | production of a molding defect.

  The solvent is preferably at least one selected from the group consisting of toluene, cyclohexanone and propylene glycol monomethyl ether acetate. According to such a structure, the resin varnish which can manufacture electronic components, such as a printed wiring board, suppresses generation | occurrence | production of a shaping | molding defect more is obtained. This was obtained because the boiling points of toluene, cyclohexanone and propylene glycol monomethyl ether acetate are relatively high and the polyarylene ether copolymer (A) and the brominated epoxy resin (B) can be dissolved. This is thought to be because the prepreg has an appropriate drying rate.

  The prepreg according to the present invention is obtained by impregnating a fibrous base material with the resin varnish. According to such a configuration, it is suitably used for producing a metal-clad laminate having excellent dielectric properties, heat resistance of a cured product, and flame retardancy, and further, the viscosity of the insulating resin composition is Since it is low and has high fluidity, it is possible to obtain a product with excellent reliability capable of suppressing the occurrence of molding defects when producing a metal-clad laminate or a printed wiring board.

  In addition, the metal-clad laminate according to the present invention is obtained by laminating a metal foil on the prepreg and molding by heating and pressing. According to this configuration, a highly reliable metal-clad laminate that can produce a printed wiring board excellent in dielectric properties, heat resistance of a cured product, and flame retardancy while suppressing the occurrence of molding defects is obtained. .

  Moreover, the printed wiring board concerning this invention was manufactured using the said prepreg, It is characterized by the above-mentioned. According to this structure, the thing which was excellent in dielectric characteristics, the heat resistance of hardened | cured material, and a flame retardance, and also suppressed generation | occurrence | production of the molding defect is obtained.

  According to the present invention, it is possible to provide an insulating resin composition that is excellent in dielectric properties and heat resistance of a cured product, has a low viscosity when formed into a varnish, and has high flame retardancy. Moreover, a resin varnish containing the insulating resin composition, a prepreg obtained using the resin varnish, a metal-clad laminate obtained using the prepreg, and a printed wiring board produced using the prepreg Provided.

  The insulating resin composition according to the embodiment of the present invention has an intrinsic viscosity of 0.03 to 0.12 dl / g measured in methylene chloride at 25 ° C., and has an average of 1 phenolic hydroxyl group per molecule terminal. 0.5 to 3 polyarylene ether copolymer (A), brominated epoxy resin (B) having a bromine content of 25 to 45% and a solubility in toluene of 10% by mass or more at 25 ° C., And a curing accelerator (C).

[Polyarylene ether copolymer (A)]
The polyarylene ether copolymer (A) has an intrinsic viscosity of 0.03 to 0.12 dl / g measured in methylene chloride at 25 ° C., and an average of 1 phenolic hydroxyl group per molecule. The polyarylene ether copolymer having 5 to 3 is not particularly limited.

  Moreover, although the said intrinsic viscosity should just be 0.03-0.12 dl / g, it is preferable that it is 0.06-0.095 dl / g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and it is difficult to obtain a cured product having sufficient heat resistance. Moreover, when the said intrinsic viscosity is too high, there exists a tendency for a viscosity to be high and sufficient fluidity | liquidity not to be obtained and for a molding defect to be suppressed.

  In addition, the said intrinsic viscosity here can be known from the specification value of the product of the said polyarylene ether copolymer (A) to be used. The intrinsic viscosity here is an intrinsic viscosity measured in methylene chloride at 25 ° C. More specifically, for example, a 0.18 g / 45 ml methylene chloride solution (liquid temperature 25 ° C.) is used as a viscometer. It is the value measured by. Examples of the viscometer include AVS500 Visco System manufactured by Schott.

  In addition, the polyarylene ether copolymer (A) may have an average number (number of terminal hydroxyl groups) per molecule of phenolic hydroxyl groups at the molecular terminals of 1.5 to 3, but 1.8 to The number is preferably 2.4. When the number of terminal hydroxyl groups is too small, the reactivity with the epoxy group of the brominated epoxy resin (B) is lowered, and it tends to be difficult to obtain a sufficient heat resistance of the cured product. On the other hand, when the number of terminal hydroxyl groups is too large, the reactivity of the brominated epoxy resin (B) with the epoxy group becomes too high, for example, the storage stability of the insulating resin composition is reduced, the dielectric constant and the dielectric loss tangent There is a risk of problems such as an increase in

  Here, the number of hydroxyl groups of the polyarylene ether copolymer (A) can be understood from the standard value of the product of the low molecular weight polyphenylene ether used. Specific examples of the number of terminal hydroxyl groups include, for example, the number of hydroxyl groups per molecule of all the polyarylene ether copolymers (A) present in 1 mol of the polyarylene ether copolymer (A). A numerical value representing an average value can be used.

  Therefore, since the polyarylene ether copolymer (A) has a relatively low molecular weight and a relatively large number of terminal hydroxyl groups, it is considered that the polyarylene ether copolymer (A) is likely to form a three-dimensional crosslink with the brominated epoxy resin (B). . Therefore, by using the polyarylene ether copolymer (A), not only has good dielectric properties in a wide frequency range, but also has sufficient fluidity to suppress molding defects, and further the heat resistance of the cured product. Is considered to be sufficiently enhanced.

  Moreover, as said polyarylene ether copolymer (A), it is preferable that a number average molecular weight (Mn) is 500-3000, and it is more preferable that it is 650-1500. Moreover, when molecular weight is too low, there exists a tendency for sufficient thing as heat resistance of hardened | cured material not to be obtained. On the other hand, if the molecular weight is too high, the melt viscosity becomes high, sufficient fluidity cannot be obtained, and molding defects tend not to be suppressed.

  In addition, the number average molecular weight of the said polyarylene ether copolymer (A) in this invention can be specifically measured using a gel permeation chromatography etc., for example.

  Specific examples of the polyarylene ether copolymer (A) include polyarylene ether copolymers composed of 2,6-dimethylphenol and bifunctional phenol, and poly (2,6-dimethyl-1,4). Examples thereof include polyphenylene ethers such as -phenylene oxide). Moreover, as said bifunctional phenol, tetramethylbisphenol A etc. are mentioned, for example. More specifically, examples of the polyarylene ether copolymer (A) include polyarylene ether copolymers having a structure represented by the following general formula (1).

  In said formula (1), m and n should just be a polymerization degree which becomes in the range of the said melt viscosity. Specifically, the total value of m and n is preferably 1-30. Further, m is preferably 0 to 20, and n is preferably 0 to 20.

[Brominated epoxy resin (B)]
The brominated epoxy resin (B) preferably contains an epoxy resin having a bromine content of 25 to 45% and a solubility in toluene of 10% by mass or more at 25 ° C.

  Specific examples include brominated phenol novolac type epoxy resins. These may be used alone or in combination of two or more.

  The bromine content of the brominated epoxy resin (B) represents the ratio of the molecular weight of bromine to the molecular weight of the epoxy resin, and is preferably 25 to 45%, more preferably 30 to 40%. If the proportion of the molecular weight of bromine is lower than 25%, flame retardancy cannot be ensured, and if it is higher than 45%, bromine groups in the epoxy resin are likely to be eliminated, and this eliminated bromine group is the cause. There is a tendency for heat resistance to deteriorate.

The epoxy equivalent of the brominated epoxy resin is preferably less than 300 g / eq. When the epoxy equivalent is greater than 300 g / eq, the heat resistance tends to deteriorate due to a decrease in the crosslinking density of the cured product.

  The brominated epoxy resin (B) preferably has an average of two or more epoxy groups in one molecule. If the average number of epoxy groups in one molecule is 2 or more, it is preferable from the point of increasing the heat resistance of the cured product of the obtained epoxy insulating resin composition. The number of epoxy groups means the average of epoxy groups per molecule because the epoxy resin has a molecular weight distribution, and the number of epoxy groups here is known from the standard value of the product of the epoxy resin used. Specific examples of the number of epoxy groups in the epoxy resin include a numerical value representing an average value of epoxy groups per molecule of all the epoxy resins present in 1 mol of the epoxy resin.

  Further, since the brominated epoxy resin (B) has a solubility in toluene of 10% by mass or more at 25 ° C., the compatibility with the polyarylene ether copolymer (A) is relatively high. Therefore, it is considered that the polyarylene ether copolymer (A) easily reacts uniformly, and three-dimensional crosslinks are easily formed with the polyarylene ether copolymer (A). Therefore, by using the brominated epoxy resin (B), the cured product has sufficient heat resistance without inhibiting the excellent dielectric properties and fluidity of the polyarylene ether copolymer (A). It is thought that it is raised.

  From the above, it is considered that the three-dimensional crosslinking can be suitably advanced by using the polyarylene ether copolymer (A) and the brominated epoxy resin (B) in combination. Furthermore, the polyarylene ether copolymer (A) has a relatively low viscosity in solution of 0.03 to 0.12 dl / g measured in methylene chloride at 25 ° C., and the brominated epoxy Since the compatibility with the resin (B) is high, it is thought that the viscosity when a solvent is added to the obtained insulating resin composition to make a resin varnish becomes low.

[Curing accelerator (C)]
The curing accelerator (C) is not particularly limited as long as it can accelerate the curing reaction between the polyarylene ether copolymer (A) and the brominated epoxy resin (B). be able to.

  Specifically, for example, imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, Organic phosphine compounds such as phenylphosphine, tributylphosphine, trimethylphosphine, etc., tertiary amine compounds such as 1,8-diaza-bicyclo (5,4,0) undecene-7 (DBU), triethanolamine, benzyldimethylamine, etc. And fatty acid metal salts.

  The fatty acid metal salt is generally called a metal soap. Specifically, for example, fatty acids such as stearic acid, lauric acid, ricinoleic acid, and octylic acid, lithium, magnesium, calcium, Examples include fatty acid metal salts composed of metals such as barium and zinc. More specifically, zinc octylate etc. are mentioned. The said hardening accelerator (C) may be used independently, or may be used in combination of 2 or more type.

  Moreover, the resin composition may further contain at least one of an aromatic amine compound and a phenol resin having a solubility in toluene of 10% by mass or more at 25 ° C. By using this curing agent, an insulating resin composition superior in dielectric properties and heat resistance of the cured product can be obtained. This is because the aromatic amine compound and the phenol resin function as a curing agent for the brominated epoxy resin (B) and are highly compatible with the polyarylene ether copolymer (A). This is considered to be because the curing reaction of the brominated epoxy resin (B) can be promoted without inhibiting the curing reaction between the arylene ether copolymer (A) and the brominated epoxy resin (B).

  Among the above, the curing accelerator (C) preferably contains an imidazole compound from the viewpoint of obtaining an insulating resin composition excellent in dielectric properties and heat resistance of the cured product. It is more preferable to contain a system compound and a fatty acid metal salt. This is because not only the curing reaction between the polyarylene ether copolymer (A) and the brominated epoxy resin (B) but also the brominated epoxy resin (B) between the imidazole compound and the fatty acid metal salt. Since the curing reaction can also be accelerated, even when the brominated epoxy resin (B) is excessively contained, the cured reaction of the brominated epoxy resin (B) causes This is thought to be due to the contribution to improving heat resistance.

[Content of each component]
In addition, the content of the polyarylene ether copolymer (A) is 45 to 75 with respect to 100 parts by mass of the total amount of the polyarylene ether copolymer (A) and the brominated epoxy resin (B). It is preferable that it is a mass part, and it is more preferable that it is 50-70 mass parts. As described above, when the content of the polyarylene ether copolymer (A) is relatively large, the cured product can be toughened while being a thermosetting resin, and elongation and deflection are increased. Moreover, when there is too little said polyarylene ether copolymer (A), it exists in the tendency which cannot maintain the outstanding dielectric property which a polyarylene ether copolymer (A) has.

  Moreover, when there are too many said polyarylene ether copolymers (A), there exists a tendency for the heat resistance of hardened | cured material to become inadequate. That is, when the content of the polyarylene ether copolymer (A) is within the above range, the dielectric properties and the heat resistance of the cured product are excellent, the viscosity when made into a varnish is low, and the polyarylene ether copolymer The excellent dielectric properties of the combined body (A) can be exhibited, and an insulating resin composition having high flame retardancy can be obtained.

  Moreover, the equivalent ratio (epoxy group equivalent / hydroxyl group equivalent) of the epoxy group of the brominated epoxy resin (B) per one phenolic hydroxyl group of the polyarylene ether copolymer (A) is 1 to 4. It is preferable that it is 1-3. By doing in this way, the insulating resin composition excellent in the dielectric property and the heat resistance of hardened | cured material is obtained. This is because even if the epoxy group of the brominated epoxy resin (B) is more than the phenolic hydroxyl group of the polyarylene ether copolymer (A), the curing reaction between the brominated epoxy resins (B) is performed. This is thought to be due to the contribution to improving the heat resistance of the cured product. Moreover, when an imidazole type compound, a fatty acid metal salt, etc. are used as the said hardening accelerator (C), it is thought that it can contribute to the improvement of the heat resistance of hardened | cured material especially.

  On the other hand, if the equivalent ratio is too low, the brominated epoxy resin (B) has too few epoxy groups, and the polyarylene ether copolymer (A) and the brominated epoxy resin (B) have a curing reaction. There is a tendency not to progress sufficiently. If the equivalent ratio is too high, the proportion of the curing reaction between the brominated epoxy resins (B) in the curing reaction of the insulating resin composition becomes too high, that is, the polyarylene ether copolymer (A ) And the brominated epoxy resin (B), the ratio of the curing reaction tends to be too low, and the heat resistance of the cured product tends to be insufficient.

  As content of the said hardening accelerator (C), for example, when containing an imidazole compound as the said hardening accelerator (C), content of the said imidazole compound is the said polyarylene ether copolymer (A). It is preferable that it is 0.05-1 mass part with respect to 100 mass parts of total amounts of and the said brominated epoxy resin (B).

  Further, when the fatty acid metal salt is used in combination with the imidazole compound, the content of the fatty acid metal salt is a total amount of the polyarylene ether copolymer (A) and the brominated epoxy resin (B) of 100. It is preferable that it is 0.5-3 mass parts with respect to a mass part. When there is too little content of the said hardening accelerator (C), it exists in the tendency which cannot improve a hardening acceleration effect. Moreover, when too large, there exists a tendency which produces a malfunction in a moldability, and there exists a tendency which becomes too economically disadvantageous because there is too much content of a hardening accelerator. Moreover, there exists a tendency for the life property of an insulating resin composition to fall.

[Other composition]
The insulating resin composition includes the above-described compositions (polyarylene ether copolymer (A), brominated epoxy resin (B), and curing accelerator ( A composition other than C)) may be contained. Specifically, for example, the following may be contained.

  The insulating resin composition may contain an inorganic filler. By containing an inorganic filler, flame retardancy can be further enhanced. In addition, the insulating resin composition has a low cross-linking density compared to a general epoxy insulating resin composition for an insulating base material, and the thermal expansion coefficient of the cured product, particularly at a temperature exceeding the glass transition temperature. The thermal expansion coefficient α2 tends to increase. By including an inorganic filler, it has excellent dielectric properties and heat resistance of the cured product, and the viscosity when made into a varnish is low, while the thermal expansion coefficient of the cured product, in particular, heat at a temperature exceeding the glass transition temperature. It is possible to reduce the expansion coefficient α2 and toughen the cured product.

  Specific examples of the inorganic filler include silica, alumina, talc, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, aluminum borate, barium sulfate, and calcium carbonate. In addition, the inorganic filler may be used as it is, but it is particularly preferable that the surface is treated with an epoxy silane type or amino silane type silane coupling agent. A metal-clad laminate obtained by using an insulating resin composition containing an inorganic filler surface-treated with a silane coupling agent as described above has high heat resistance during moisture absorption and high interlayer peel strength. Tend to be.

  The insulating resin composition may further contain, for example, additives such as a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye, a pigment, and a lubricant as long as the effects of the present invention are not impaired. Also good.

[Adjustment of varnish]
When the prepreg is produced, the insulating resin composition is often prepared and used in the form of a varnish for the purpose of impregnating a base material (fibrous base material) for forming the prepreg. That is, the insulating resin composition is usually often prepared in a varnish form (resin varnish). Such a resin varnish is prepared as follows, for example.

  First, each component that can be dissolved in an organic solvent, such as the polyarylene ether copolymer (A) and the brominated epoxy resin (B), is added to the organic solvent and dissolved. At this time, heating may be performed as necessary. After that, a component that is used as necessary and does not dissolve in an organic solvent, such as an inorganic filler, is added and dispersed using a ball mill, a bead mill, a planetary mixer, a roll mill or the like until a predetermined dispersion state is obtained. Thus, a varnish-like insulating resin composition is prepared. The organic solvent is not particularly limited as long as it dissolves the polyarylene ether copolymer (A) and the brominated epoxy resin (B) and does not inhibit the curing reaction. Specifically, toluene etc. are mentioned, for example.

[Method for producing prepreg]
Examples of a method for producing a prepreg using the obtained resin varnish include a method of impregnating a fibrous base material with the resin varnish and then drying.

  Specific examples of the fibrous base material include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. When a glass cloth is used, a laminate having excellent mechanical strength can be obtained, and a flat glass processed glass cloth is particularly preferable. Specifically, the flattening processing can be performed, for example, by continuously pressing a glass cloth with a press roll at an appropriate pressure and compressing the yarn flatly. In addition, as a thickness of the said fibrous base material, the thing of 0.02-0.3 mm can generally be used, for example.

  The impregnation is performed by dipping or coating. The impregnation can be repeated a plurality of times as necessary. At this time, it is also possible to repeat the impregnation using a plurality of resin varnishes having different compositions and concentrations, and finally adjust to a desired composition and resin amount.

  The fibrous base material impregnated with the resin varnish is heated at a desired heating condition, for example, 80 to 170 ° C. for 1 to 10 minutes to obtain a semi-cured (B stage) prepreg.

  As a method for producing a metal-clad laminate using the prepreg thus obtained, one or a plurality of the prepregs are stacked, and a metal foil such as a copper foil is stacked on both upper and lower surfaces or one surface thereof. By heating and pressing to laminate and integrate, a double-sided metal foil-clad laminate or a single-sided metal foil-clad laminate can be produced. The heating and pressing conditions can be appropriately set depending on the thickness of the laminate to be produced, the type of the prepreg insulating resin composition, etc., for example, the temperature is 170 to 220 ° C., the pressure is 2.0 to 4.0 MPa, The time can be 60-150 minutes.

  The insulating resin composition is excellent in dielectric properties and heat resistance of a cured product, has a low viscosity when formed into a varnish, and exhibits high flame retardancy. For this reason, the metal-clad laminate using the prepreg obtained using the insulating resin composition is a printed wiring board excellent in dielectric properties, heat resistance, and flame retardancy while suppressing the occurrence of molding defects. It can be manufactured and has high reliability.

  And the printed wiring board which provided the conductor pattern as a circuit on the surface of a laminated body can be obtained by carrying out the etching process etc. of the metal foil on the surface of the produced laminated body. The printed wiring board thus obtained has excellent dielectric properties, heat resistance, and flame retardancy, and further suppresses the occurrence of molding defects.

  The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited to these examples.

[Preparation of insulating resin composition]
In this example, each component used when preparing the insulating resin composition will be described. Here, the intrinsic viscosity measured in methylene chloride at 25 ° C. is shown as intrinsic viscosity (IV), and the solubility in toluene at 25 ° C. is shown as toluene solubility.

(Polyarylene ether copolymer: PAE)
PAE 1: Polyarylene ether copolymer (MX-90 manufactured by SABIC Innovative Plastics, intrinsic viscosity (IV) 0.085 dl / g, number of terminal hydroxyl groups 1.9, number average molecular weight Mn1050)
PAE 2: Polyarylene ether copolymer synthesized by the method described in International Publication No. 2008/0667669 (Inherent viscosity (IV) 0.06 dl / g, number of terminal hydroxyl groups 1.8, number average molecular weight Mn800)
PAE 3: Polyarylene ether copolymer synthesized by the method described in International Publication No. 2008/0667669 (Intrinsic viscosity (IV) 0.09 dl / g, terminal hydroxyl number 2.8, number average molecular weight Mn 1150)
PAE 4: Polyarylene ether copolymer (SA120 manufactured by SABIC Innovative Plastics, intrinsic viscosity (IV) 0.125 dl / g, terminal hydroxyl number 1.2, number average molecular weight Mn 2350)

(Brominated epoxy resin)
Brominated epoxy resin 1: brominated phenol novolak type epoxy resin (BREN-105 manufactured by Nippon Kayaku Co., Ltd., bromine content 35.5%, epoxy equivalent 275, toluene solubility 75 mass%)
Brominated epoxy resin 2: Tetrabromobisphenol A type epoxy resin (Epiclon 153 manufactured by DIC Corporation, bromine content 48%, epoxy equivalent 400, toluene solubility 70 mass%)
Brominated epoxy resin 3: tetrabromobisphenol A type epoxy resin (Epiclon 1121N manufactured by DIC Corporation, bromine content 21%, epoxy equivalent 495, toluene solubility 40% by mass)
Epoxy resin 4: dicyclopentadiene type epoxy resin (Epiclon HP7200 manufactured by DIC Corporation, bromine content 0%, epoxy equivalent 258, toluene solubility 80 mass%)

(Curing accelerator)
Imidazole-based compound: 2-ethyl-4-methylimidazole (2E4MZ manufactured by Shikoku Kasei Kogyo Co., Ltd.)
Fatty acid metal salt (metal soap): zinc octoate (manufactured by DIC Corporation)

(Other ingredients)
Aromatic amine compound: diethyltoluenediamine (Etacure 100 manufactured by Albemarle Japan, Inc., toluene solubility 100% by mass)
Phenol resin: Phenol resin (DPP-6115S manufactured by Nippon Oil Corporation, toluene solubility 25% by mass)
Silica particles: Silica particles (SC2500-SEJ manufactured by Admatechs Co., Ltd.)

[Preparation method]
First, the polyarylene ether copolymer and toluene are mixed, and the mixed liquid is heated to 80 ° C., so that the polyarylene ether copolymer is dissolved in toluene and the polyarylene ether copolymer is dissolved. A 50 mass% toluene solution was obtained. Then, after adding an epoxy resin to the toluene solution of the polyarylene ether copolymer so as to have the blending amounts shown in Tables 1 to 3, the solution was completely dissolved by stirring for 30 minutes. Further, by adding other components such as an imidazole compound and a bromine compound, and dispersing with a bead mill, a varnish-like insulating resin composition (resin varnish) was obtained.

  Next, the obtained resin varnish was impregnated into glass cloth (# 2116 type, WEA116E, E glass manufactured by Nitto Boseki Co., Ltd.) and then dried by heating at 140 ° C. for about 3 to 8 minutes to obtain a prepreg. .

And 4 sheets of each obtained prepreg were laminated | stacked and laminated | stacked, and the evaluation board | substrate of thickness 0.5mm was obtained by heat-pressing on the conditions of temperature 200 degreeC, 2 hours, and pressure 3MPa.
Each prepreg and evaluation substrate prepared as described above were evaluated by the following method.

[Dielectric properties (dielectric constant and dielectric loss tangent)]
The dielectric constant and dielectric loss tangent of the evaluation board | substrate (board | substrate thickness of 0.5 mm) in 1 GHz were measured by the method based on IPC-TM650-2.5.5.9. Specifically, the dielectric constant and dielectric loss tangent of the evaluation board | substrate in 1 GHz were measured using the impedance analyzer (RF impedance analyzer HP4291B by Agilent Technologies).

[Glass transition temperature (Tg)]
In the above, Tg was measured about the produced evaluation board | substrate using Seiko Instruments Inc. viscoelasticity spectrometer "DMS100". At this time, measurement was performed with a bending module at a frequency of 10 Hz, and the temperature at which tan δ was maximized when the temperature was raised from room temperature to 280 ° C. under a temperature rising rate of 5 ° C./min was Tg.

[Oven heat resistance]
The oven heat resistance was evaluated by adjusting the evaluation substrate having a thickness of about 0.5 mm prepared above to 260 ° C. in an oven. If the occurrence of measling or swelling could not be confirmed, it was evaluated as “◯”, and if it was confirmed, it was evaluated as “x”. Separately, the same evaluation was performed by adjusting to 280 ° C. instead of 260 ° C.

[Flame retardance]
A test piece having a length of 125 mm and a width of 12.5 mm was cut out from the evaluation substrate. Then, this test piece was evaluated according to "Test for Flammability of Plastic Materials-UL 94" of Underwriters Laboratories. At that time, if the average combustion time is 5 seconds or less and the maximum combustion time is 10 seconds or less, it corresponds to V-0, and if the average combustion time is 25 seconds or less and the maximum combustion time is 30 seconds or less, V-1 If the test piece burned out and became ash, it was completely burned.

[Solubility of resin solution]
The obtained resin varnish was cooled to room temperature and allowed to stand for 1 day, and then the transparency of the resin varnish was visually confirmed. If it was confirmed that it was transparent, it was evaluated as “◯”, if it was confirmed that it was translucent, “Δ”, and if it was confirmed that it was cloudy, it was evaluated as “x”.

[Resin flowability of prepreg]
The resin flowability of each prepreg was measured by a method based on JIS C 6521.

[Appearance of laminated sheet]
The evaluation board was visually evaluated. The evaluation board was visually evaluated. If voids, scum, separation of resin, etc. were confirmed, it was evaluated as “x”, otherwise it was evaluated as “◯”.

  The results in the above evaluations are shown in Tables 1 to 3.

  As is apparent from Examples 1 to 5 in Table 1, the intrinsic viscosity measured in methylene chloride at 25 ° C. is 0.03 to 0.12 dl / g, and the phenolic hydroxyl groups are averaged per molecule at the molecular terminals. 1.5 to 3 polyarylene ether copolymer (A), brominated epoxy resin (B) having a bromine content of 35.5% and a solubility in toluene of 10% by mass or more at 25 ° C. In the case of using an insulating resin composition containing a curing accelerator (C), solder heat resistance, flame retardancy, solubility, and prepreg resin without deteriorating dielectric properties such as dielectric constant and dielectric loss tangent It was excellent in all flow properties, and the viscosity increase of the resin varnish was small.

  Moreover, content of (A) is 45-75 mass parts with respect to 100 mass parts of resin compositions, and content of the said epoxy resin (B) is 25-55 with respect to 100 mass parts of resin compositions. It was found that the desired result could be obtained with the mass part. On the other hand, in Comparative Example 1 of Table 1, an insulating resin composition containing a polyarylene ether copolymer having an intrinsic viscosity (IV) of more than 0.12 dl / g and a terminal hydroxyl group number of less than 1.5 is used. Therefore, the oven heat resistance at 280 ° C., the solubility of the resin solution, the resin flowability of the prepreg, and the appearance of the laminate were inferior. This is considered to be because sufficient fluidity was not obtained due to the high intrinsic viscosity, and molding defects could not be suppressed.

  Further, Comparative Example 2 in Table 2 contained a bromine content as high as 48% and a brominated epoxy resin having a high epoxy equivalent of 400 g / eq, so that the glass transition temperature was low and the oven heat resistance was 260. The results were inferior at both ℃ and 280 ℃. In Comparative Example 3, since a brominated epoxy resin having a bromine content of 21% and an epoxy equivalent of 495 g / eq was used, the result was inferior in flame retardancy, and the glass transition temperature was low. In Comparative Example 4, since an epoxy resin containing no bromine content was contained, the result was inferior in flame retardancy.

  Moreover, as is clear from Examples 6 to 9 in Table 3, even when an aromatic amine compound or a phenol resin was further contained, the same excellent results as in the above examples were obtained. It was also found that the desired result was obtained when a fatty acid metal salt or silica particles were contained.

Claims (7)

A polyarylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12 dl / g measured in methylene chloride at 25 ° C. and having an average of 1.5 to 3 phenolic hydroxyl groups per molecule at the molecular terminals ( A) and
A brominated epoxy resin (B) having an epoxy equivalent of less than 300 g / eq and a bromine content of 25 to 45% and a solubility in toluene of 10% by mass or more at 25 ° C .;
A curing accelerator (C);
Contain,
Content of the said polyarylene ether copolymer (A) is 45-75 mass parts with respect to 100 mass parts of resin compositions, and content of the said brominated epoxy resin (B) is 100 mass parts of resin compositions. insulating resin composition characterized 25-55 parts by der Rukoto respect.   The insulating resin composition according to claim 1, wherein the polyarylene ether copolymer (A) comprises 2,6-xylenol and at least one of a bifunctional phenol and a trifunctional phenol. The insulating resin composition according to claim 1 or 2 , further comprising at least one of an aromatic amine compound and a phenol resin having a solubility in toluene at 25 ° C of 10% by mass or more. A resin varnish containing the insulating resin composition according to any one of claims 1 to 3 and a solvent. A prepreg obtained by impregnating a fibrous base material with the resin varnish according to claim 4 . A metal-clad laminate obtained by laminating a metal foil on the prepreg according to claim 5 and then heat-pressing it. A printed wiring board manufactured using the prepreg according to claim 5 .