JP2011046815A - Liquid thermosetting resin composition and copper-clad laminate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve flexural modulus and flexural strength of a cured product of a liquid thermosetting resin composition used for production of a copper-clad laminate etc. <P>SOLUTION: The liquid thermosetting resin composition contains (A) a cyanate ester compound that has two or more cyanate ester groups in one molecule, (B) a radically polymerizable compound that has two or more unsaturated double bonds in one molecule and has no hydroxyl group in the molecule while having a ring structure formed from only carbon and hydrogen in the molecule, (C) an epoxy resin that has two or more epoxy groups in one molecule, and (D) a radical polymerization initiator. The radically polymerizable compound (B) is a vinyl ester resin, and a content thereof is 10-70 mass% of the total amount of the cyanate ester compound (A), the radically polymerizable compound (B), and the epoxy resin (C). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid thermosetting resin composition used for producing a copper-clad laminate and the like and a copper-clad laminate using the same.

  Conventionally, as a liquid thermosetting resin composition used for producing a copper clad laminate or the like, for example, there is one in which a radical polymerizable compound such as a vinyl ester resin and an epoxy resin are blended.

  In general, a radical polymerizable compound is cured by a radical reaction, so that the curing time is relatively short (excellent in quick curing) and the impregnation property to a substrate such as glass cloth is excellent. It has the disadvantage of relatively low mechanical properties and heat resistance. On the other hand, the epoxy resin has the advantages that the cured product has relatively high mechanical properties and heat resistance, but has the disadvantage that the curing time is relatively long and the viscosity of the resin is high, so the impregnation property to the substrate is poor. There is.

  Therefore, by using a combination of a radical polymerizable compound and an epoxy resin, the mechanical properties and low heat resistance of the cured product, which are disadvantages of the radical polymerizable compound, are improved, and the curing time which is a disadvantage of the epoxy resin is improved. A thermosetting resin composition with improved length and low impregnation properties will be obtained.

  Furthermore, as described in Patent Documents 1 and 2, by adding a cyanate ester compound to the thermosetting resin composition, the glass transition temperature (Tg) of the cured product is increased, and the heat resistance of the cured product is improved. It is known to be further improved.

JP 2009-73996 A (paragraphs 0025 to 0028) JP 2003-283125 A (paragraphs 0010 to 0011)

  Nevertheless, conventional thermosetting resin compositions have not been sufficient in terms of mechanical properties required for recent copper-clad laminates, particularly bending elastic modulus and bending strength. In order to solve this problem, for example, a phenol compound such as a phenol novolac resin used as a curing agent for an epoxy resin may be blended in the thermosetting resin composition. However, since the phenolic hydroxyl group of the phenol compound acts as a radical polymerization inhibitor, it is not preferable to add a phenol compound to the thermosetting resin composition containing the radical polymerizable compound.

  The present invention addresses the above-mentioned problems in liquid thermosetting resin compositions used for the production of copper-clad laminates, etc., and the cured product has more mechanical properties, particularly bending elastic modulus and bending strength. An object is to provide a further improved liquid thermosetting resin composition and a copper-clad laminate using the same.

  That is, the liquid thermosetting resin composition of the present invention includes (A) a cyanate ester compound having two or more cyanate ester groups in one molecule, and (B) two or more unsaturated double bonds in one molecule. And having a ring structure formed only from carbon and hydrogen in the molecule and having no hydroxyl group in the molecule, (C) having two or more epoxy groups in one molecule It contains an epoxy resin and (D) a radical polymerization initiator (claim 1). According to such a configuration, the ring structure of the radically polymerizable compound of the component (B) contributes to the stiffening of the cured product, and contributes to the improvement of the mechanical properties of the cured product, particularly the flexural modulus and bending strength. To do. Moreover, since the radically polymerizable compound of the component (B) does not have a hydroxyl group, it does not act as a radical polymerization inhibitor and does not lower the glass transition temperature of the cured product.

  In the present invention, the (B) radical polymerizable compound may be contained in an amount of 10 to 70% by mass in the total amount of the (A) cyanate ester compound, the (B) radical polymerizable compound, and the (C) epoxy resin. This is preferable from the viewpoint of the balance between the advantages (excellent curability and excellent impregnation property) and disadvantages (low mechanical properties and low heat resistance of the cured product) of the radical polymerizable compound (claim 2).

  In the present invention, (B) the radically polymerizable compound is at least one selected from the group consisting of the compound represented by Formula 1 and the vinyl ester resin represented by Formula 2; This is preferable from the viewpoint of surely contributing to improvement of the elastic modulus and bending strength.

  In the present invention, the addition of (E) a cyanate ester compound curing accelerator further promotes the formation of a rigid structure by (A) the cyanate ester compound. As a result, the cured product becomes rigid, flexural modulus and bending. This is preferable from the viewpoint of further improving the strength (claim 4).

  That is, the liquid thermosetting resin composition of the present invention is originally composed of (A) a cyanate ester compound in a three-component system of (A) a cyanate ester compound, (B) a radical polymerizable compound, and (C) an epoxy resin. Combined with the formation of the rigid structure and the formation of the rigid structure due to the ring structure of the (B) radical polymerizable compound, the cured product is further stiffened, and further bending elastic modulus and bending strength of the cured product are improved. Improvement is intended.

  In this invention, 100-200 mass parts of (F) inorganic filler is contained with respect to 100 mass parts of total amounts of (A) cyanate ester compound, (B) radical polymerizable compound, and (C) epoxy resin. It is preferable from the viewpoint that the processability of the thermosetting resin composition can be maintained while improving the dimensional stability and flame retardancy of the cured product.

  In the present invention, it is preferable to further contain (G) a radical reactive diluent from the viewpoint of reducing the viscosity of the liquid thermosetting resin composition and ensuring good impregnation to the substrate (claims). 6).

  And the copper clad laminated board of this invention has the resin insulating layer comprised by the hardened | cured material which hardened said liquid thermosetting resin composition, and the copper foil layer laminated | stacked on this resin insulating layer ( Claim 7). According to such a configuration, since the resin insulating layer is formed of a cured product, the resin insulating layer is stiffened, the bending elastic modulus and the bending strength are improved, and the glass transition temperature is prevented from being lowered. The illustrated copper clad laminate is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid thermosetting resin composition in which the mechanical characteristics of hardened | cured material, especially bending elastic modulus and bending strength were improved further, and a copper clad laminated board using the same are provided.

(Component A)
The component (A) contained in the liquid thermosetting resin composition of the present invention is a cyanate ester compound having two or more cyanate ester groups in one molecule. A cyanate ester compound acts as a curing agent for an epoxy resin by reacting a cyanate ester group (—OCN) with an epoxy group. The cyanate ester compound forms a rigid structure in the three-dimensional network structure having a cross-linked structure with an epoxy resin or a radical polymerizable compound. As a result, the glass transition temperature (Tg) of the cured product is increased, the heat resistance of the cured product is improved, and the bending elastic modulus and bending strength of the cured product are improved. Further, since the cyanate ester compound has a low viscosity, it contributes to the improvement of the fluidity and impregnation of the varnish (resin solution) and thus the liquid thermosetting resin composition.

  In addition, the cyanate ester compound trimerizes by a self-polymerization reaction to generate a triazine ring, or generates an oxazoline ring by reaction with an epoxy resin. As a result, the crosslink density of the resin is increased, a more rigid structure is formed, and the heat resistance, bending elastic modulus and bending strength of the cured product are further improved.

  The (A) cyanate ester compound used in the present invention can be used without particular limitation as long as it is a compound having two or more cyanate ester groups in one molecule. Specific examples thereof include, for example, bisphenol type cyanate ester compounds such as bisphenol A type, bisphenol F type, and bisphenol S type, novolak type cyanates such as phenol novolak type, cresol novolak type, bisphenol A novolak type, and dicyclopentadiene novolak type. Examples include ester compounds, alicyclic cyanate ester compounds, and heterocyclic cyanate ester compounds. These may be used alone or in combination of two or more.

  The higher the content of (A) cyanate ester compound in the total amount of (A) cyanate ester compound, (B) radical polymerizable compound and (C) epoxy resin (in all resin components), the higher the content of (B) radical polymerization. The content of the functional compound is decreased, and the curing time of the thermosetting resin composition tends to be longer. On the contrary, as the content of the (A) cyanate ester compound in all the resin components decreases, the improvement of the heat resistance, bending elastic modulus and bending strength of the cured product tends to be insufficient. From the viewpoint of balancing and balancing such characteristics, the content of the (A) cyanate ester compound in all resin components is preferably 10 to 90 mass%, more preferably 15 to 60 mass%, and more preferably 20 to 40 mass%. More preferred is mass%.

  (A) The number of cyanate ester groups in one molecule of the cyanate ester compound is preferably 5 or less. Moreover, in order to avoid acting as a radical polymerization inhibitor, the (A) cyanate ester compound which does not have a hydroxyl group in a molecule | numerator is preferable.

(B component)
The component (B) contained in the liquid thermosetting resin composition of the present invention is a radical polymerizable compound having two or more unsaturated double bonds in one molecule. The radically polymerizable compound forms a three-dimensional network structure having a crosslinked structure by reacting an unsaturated double bond with an unsaturated double bond of another molecule. In general, radically polymerizable compounds are cured by a radical reaction, so that the curing time is relatively short (excelling in rapid curing) and the impregnation into a substrate such as glass cloth is excellent. It has the disadvantage of relatively low mechanical properties and heat resistance.

  Therefore, the radically polymerizable compound (B) used in the present invention has a ring structure formed only from carbon and hydrogen in the molecule. Due to this ring structure, the radically polymerizable compound (B) contributes to stiffening of the cured product, and contributes to the improvement of the mechanical properties of the cured product, particularly the flexural modulus and bending strength.

  Examples of the ring structure formed only of carbon and hydrogen include a ring structure having a π electron cloud such as a benzene ring, a saturated alicyclic ring structure such as a cycloalkane, and an unsaturated structure such as a cycloalkene. An alicyclic ring structure, a ring structure such as dicyclopentadiene obtained by dimerization of cyclopentadiene by Diels-Alder reaction, and a hydrogenated product thereof.

  In the present invention, the number and position of the ring structure in one molecule of the (B) radical polymerizable compound are not limited. For example, the number of ring structures in one molecule may be one, or two or more. When there are two or more ring structures in one molecule, these rings may be connected to each other by sharing a common ring member (carbon), or share a common ring member. Instead, they may be separated from each other.

  In the present invention, the number of ring members of one ring structure of the (B) radical polymerizable compound is not limited. For example, it may be a 3-membered ring or a ring containing 4 or more members. However, each ring structure is preferably a 3-membered ring to a 12-membered ring from the viewpoint that this ring structure contributes to stiffening of the cured product, an improvement in flexural modulus and bending strength, and a 3-membered ring to 8-membered ring. A ring is more preferable, and a 3-membered ring to a 6-membered ring is further preferable.

  The (B) radical polymerizable compound used in the present invention does not have a hydroxyl group in the molecule. As a result, the (B) radical polymerizable compound does not act as a radical polymerization inhibitor and does not lower the glass transition temperature of the cured product.

  Specific examples of the (B) radical polymerizable compound used in the present invention include, for example, dicyclopentadiene dimethacrylate, dicyclopentadiene diacrylate, bisphenol type epoxy resin (excluding those having a hydroxyl group in the molecule) and methacrylic acid. And vinyl ester resin which is a reaction product. These may be used alone or in combination of two or more.

  In the present invention, it is particularly preferable that the (B) radical polymerizable compound is at least one selected from the group consisting of a compound represented by the formula 1 and a vinyl ester resin represented by the formula 2. This is preferable from the viewpoint of surely contributing to improvement of the bending elastic modulus and bending strength of the cured product.

  The compound represented by Formula 1 is tricyclodecane dimethanol dimethacrylate (light yellow transparent liquid, specific gravity (25 ° C.) 1.077, viscosity (mPa · s / 25 ° C.) 105, refractive index (25 ° C.) 1.500. And having a saturated alicyclic ring structure in which dicyclopentadiene is hydrogenated as a ring structure formed only from carbon and hydrogen, for example, “NK Ester DCP” from Shin-Nakamura Chemical Co., Ltd. Is available under the name

  The vinyl ester resin represented by Formula 2 is a reaction product of a novolak-type epoxy resin and methacrylic acid, and has a benzene ring as a ring structure formed only from carbon and hydrogen. It is available under the name “EXP2641”.

  As the content of (B) radical polymerizable compound in the total amount (in all resin components) of (A) cyanate ester compound, (B) radical polymerizable compound and (C) epoxy resin increases, the machine of the cured product Tend to decrease the mechanical properties and heat resistance. On the contrary, as the content of the (B) radical polymerizable compound in all the resin components decreases, the curing time of the thermosetting resin composition becomes longer and the impregnation property to the substrate tends to decrease. From the viewpoint of balancing and balancing such characteristics, the content of the (B) radical polymerizable compound in all resin components is preferably 10 to 70% by mass, more preferably 20 to 50% by mass, and 30 to 30%. More preferred is 40% by mass.

  (B) The number of unsaturated double bonds in one molecule of the radical polymerizable compound is preferably 5 or less.

(C component)
The component (C) contained in the liquid thermosetting resin composition of the present invention is an epoxy resin having two or more epoxy groups in one molecule. The epoxy resin forms a three-dimensional network structure having a crosslinked structure by reacting an epoxy group with an epoxy group of another molecule. Epoxy resins generally have the advantages of relatively high mechanical properties and heat resistance of the cured product, but they have the disadvantage that the curing time is relatively long and the viscosity of the resin is high, resulting in poor impregnation into the substrate. There is.

  The (C) epoxy resin used in the present invention can be used without particular limitation as long as it is a compound having two or more epoxy groups in one molecule. Specific examples thereof include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type, and bisphenol S type, novolac type epoxy resins such as phenol novolac type, cresol novolak type, bisphenol A novolak type, and dicyclopentadiene novolak type. 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 1-epoxyethyl- Alicyclic epoxy resins such as 3,4-epoxycyclohexane, glycidyl esters such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, glycidyl dimer, tetraglycol Glycidylamines such as dildiaminodiphenylmethane, triglycidyl P-aminophenol, N, N-diglycidylaniline, heterocyclic epoxy resins such as 1,3-diglycidyl-5,5-dimethylhydantoin, triglycidyl isocyanurate, etc. Can be mentioned. These may be used alone or in combination of two or more.

  The thermosetting resin composition increases as the content of (C) epoxy resin in the total amount (in all resin components) of (A) cyanate ester compound, (B) radical polymerizable compound, and (C) epoxy resin increases. The curing time becomes longer, and the impregnation property to the substrate tends to be lowered. Conversely, as the content of the (C) epoxy resin in all the resin components decreases, the mechanical properties and heat resistance of the cured product tend to decrease. From the viewpoint of balancing and balancing such characteristics, the content of the (C) epoxy resin in all resin components is preferably 5 to 70% by mass, more preferably 30 to 60% by mass, and 40 to 50% by mass. % Is more preferable.

  (C) The number of epoxy groups in one molecule of the epoxy resin is preferably 5 or less. In order to avoid acting as a radical polymerization inhibitor, an epoxy resin (C) having no hydroxyl group in the molecule is preferable.

(D component)
Specific examples of the radical polymerization initiator (D) used in the present invention include, for example, ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide and cyclohexanone peroxide, and diacyl such as benzoyl peroxide and isobutyl peroxide. Peroxides, cumene hydroperoxide, hydroperoxides such as t-butyl hydroperoxide, dialkyl peroxides such as dicumyl peroxide, di-t-butyl peroxide, 1,1-di-t-butyl Peroxyketals such as peroxy-3,3,5-trimethylcyclohexanone, 2,2-di- (t-butylperoxy) -butane, t-butylperbenzoate, t-butylperoxy-2-ethylhexa Alkyl pare such as Noate Examples include organic peroxides such as tellurium, bis (4-t-butylcyclohexyl) peroxydicarbonate, percarbonates such as t-butylperoxyisobutylcarbonate, and inorganic oxides such as hydrogen peroxide. . These may be used alone or in combination of two or more.

  The content of (D) radical polymerization initiator is not particularly limited, but is preferably about 0.5 to 10 parts by mass with respect to 100 parts by mass of (B) radical polymerizable compound.

(E component)
Specific examples of the (E) cyanate ester compound curing accelerator used in the present invention include zinc octoate, zinc naphthenate, copper naphthenate, and iron naphthenate. These may be used alone or in combination of two or more.

  (E) The curing accelerator for the cyanate ester compound further promotes the stiffening of the (A) cyanate ester compound and thus the cured product, and further improves the bending elastic modulus and bending strength of the cured product.

  That is, the liquid thermosetting resin composition of the present invention is originally composed of (A) a cyanate ester compound in a three-component system of (A) a cyanate ester compound, (B) a radical polymerizable compound, and (C) an epoxy resin. The formation of the rigid structure and the formation of the rigid structure by the ring structure of the (B) radical polymerizable compound are intended to further stiffen the cured product and improve the flexural modulus and bending strength. is there.

  (E) Although content of the hardening accelerator of a cyanate ester compound is not specifically limited, It is preferable that it is about 0.5-5 mass parts with respect to 100 mass parts of (A) cyanate ester compounds. .

(F component)
Specific examples of the (F) inorganic filler used in the present invention include, for example, a composite containing at least two metal elements selected from the group consisting of metal hydroxides such as aluminum hydroxide, nickel, iron, cobalt, and chromium. A metal oxide, spherical silica, etc. are mentioned. These may be used alone or in combination of two or more.

  (F) An inorganic filler is mix | blended in order to maintain the dimensional stability of hardened | cured material and by extension, a copper clad laminated board, and to raise a flame retardance.

  The content of the (F) inorganic filler is not particularly limited, but the total amount (total resin component) of (A) a cyanate ester compound, (B) a radical polymerizable compound, and (C) an epoxy resin is 100 masses. 100 to 200 parts by mass with respect to parts, while improving the dimensional stability and flame retardancy of the cured product, suppresses an extreme increase in the viscosity of the thermosetting resin composition and maintains processability It is preferable from the point which can be performed.

(G component)
Specific examples of the (G) radical reactive diluent used in the present invention include, for example, 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, 4-vinylpyridine, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl. Examples include methacrylate, glycidyl methacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, and trimethylolpropane triacrylate. These may be used alone or in combination of two or more.

  (G) The radical reactive diluent can reduce the viscosity of the thermosetting resin composition in which the (B) radical polymerizable compound is blended to ensure good impregnation into the substrate.

  (G) Although content in particular of a radical reactive diluent is not restrict | limited, It is preferable that it is about 5-50 mass% in the thermosetting resin composition whole quantity.

(Other ingredients)
In the liquid thermosetting resin composition of the present invention, an imidazole compound, a flame retardant, a flame retardant aid, a flow modifier, a lubricant, a silane coupling agent, and coloring are added within a range that does not impair the object of the present invention. An additive such as an agent may be blended.

  For example, the imidazole compound contained in the liquid thermosetting resin composition of the present invention is used as a curing agent for (C) an epoxy resin. Specific examples of the imidazole compound include, for example, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole. 2-phenyl 6-4 ′, 5′-dihydroxymethylimidazole, 1-cyanoethyl-2-ethyl-4methylimidazole and the like. These may be used alone or in combination of two or more.

  As the imidazole compound used in the present invention, a compound having no amino group or hydroxyl group in the molecule is particularly preferable. Since amino groups and hydroxyl groups inhibit radical reactions, the use of an imidazole compound that does not have amino groups or hydroxyl groups increases the radical reactivity and provides a liquid thermosetting resin composition with excellent curability. It will be.

  The content ratio of the imidazole compound in the liquid thermosetting resin composition is not particularly limited as long as it is a ratio that sufficiently cures the epoxy resin (C), but the storage stability of the varnish (resin solution) (varnish life) From the point which is excellent in, it is 0.1-2 mass with respect to 100 mass parts (total resin component) of (A) cyanate ester compound, (B) radically polymerizable compound, and (C) epoxy resin. Part, more preferably 0.5 to 1.5 parts by mass. Or it is preferable to mix | blend in the range of 0.5-5 with an epoxy equivalent ratio with respect to (C) epoxy resin.

(Preparation of liquid thermosetting resin composition)
The liquid thermosetting resin composition of the present invention can be obtained by mixing the above components. The liquid thermosetting resin composition is prepared by, for example, mixing a liquid component among the above components to prepare a varnish (resin solution), and further adding an insoluble component such as an inorganic filler or a flame retardant, A thermosetting resin composition in a liquid state is finally obtained by dispersing using a bead mill or the like.

(Preparation of copper-clad laminate)
The copper clad laminate of the present invention has a structure having a resin insulating layer composed of a cured product obtained by curing the liquid thermosetting resin composition of the present invention and a copper foil layer bonded to the resin insulating layer. is there. And the production method includes an impregnation step of impregnating a base material such as glass cloth with the liquid thermosetting resin composition of the present invention, and a lamination step of pasting a copper foil on at least one surface of the base material. And a curing step of curing the thermosetting resin composition impregnated in the substrate with heat.

  Specifically, for example, a base material is continuously drawn out from a base material roll around which the base material is wound, and the liquid thermosetting resin composition of the present invention is applied to the base material and impregnated. After the copper foil is bonded to the surface of the base material impregnated with the product, the resin composition is heated and cured.

  In addition, since the radically polymerizable compound (B) contained in the resin composition undergoes radical polymerization, the curability is lowered by contact with oxygen. Therefore, when laminating copper foil only on one side of the base material, for example, by laminating a resin film such as a PET film on the other side, the resin composition impregnated in the base material ( B) It is preferable to suppress contact of the radical polymerizable compound with air.

  According to the production method described above, each of the above steps can be performed continuously, so that there is an advantage that continuous production of a copper-clad laminate is possible.

  Examples of the substrate include woven or nonwoven fabrics of inorganic fibers such as glass cloth, aramid cloth, polyester cloth, paper, and the like.

  Moreover, as copper foil used by this invention, if it is conventionally used for the use of a copper clad laminated board, it will be used without limitation, Specifically, electrolytic copper foil, rolled copper foil, etc. are used. Used.

  Moreover, although the heating conditions for curing the liquid thermosetting resin composition of the present invention depend on the composition and cannot be uniquely specified, considering continuous productivity, about 80 to 200 ° C. It is preferable to heat at a temperature of about 10 to 60 minutes (can be cured in multiple stages with different curing conditions).

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail through an Example, this invention is not limited to these Examples.

First, the raw materials used in this example are shown together (see Table 1).
(A) Cyanate ester compound / Cyanate ester compound 1: Bisphenol A type cyanate ester (“BADCy” manufactured by Lonza Japan)
Cyanate ester compound 2: Novolac type cyanate ester (“PT30” manufactured by Lonza Japan)
(B) Radical polymerizable compound / Radically polymerizable compound 1: Tricyclodecane dimethanol dimethacrylate represented by Formula 1 (“NK Ester DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Radical polymerizable compound 2: novolak type vinyl ester resin represented by Formula 2 (“EXP2641” manufactured by DIC)
(C) Epoxy resin / phenol novolac type epoxy resin (“EPICLON (registered trademark)“ N-740 ”manufactured by DIC Corporation: epoxy equivalent 170-190)
(D) Radical polymerization initiator cumene hydroperoxide (CHP)
(E) Cyanate ester compound curing accelerator, zinc octoate (DIC)
(F) Inorganic filler / aluminum hydroxide (“CL303” manufactured by Sumitomo Chemical Co., Ltd.)
Spherical silica (SiO ₂ ) (“SO25R” manufactured by Admatechs)
(Other ingredients)
・ Imidazole (“2E4MZ-CN” manufactured by Shikoku Kasei Co., Ltd.) as a curing agent for epoxy resin

(Preparation of liquid thermosetting resin composition)
All the components except the component (F) were weighed in a container at each mixing ratio shown in Table 1 and mixed to prepare a varnish (resin solution). The liquid thermosetting resin composition of Examples 1-8 and Comparative Examples 1-2 was prepared by adding (F) component to this varnish by the compounding ratio shown in Table 1, and making it disperse | distribute with a bead mill.

(Preparation of copper-clad laminate)
A glass cloth (1504 type, plain weave) is placed on a copper foil (JTC foil manufactured by Nikko Metal Co., Ltd.), impregnated with the liquid thermosetting resin composition obtained on the glass cloth, and a copper foil ( JTC foil manufactured by Nikko Metal Co., Ltd.) This was put into an oven and cured under the curing conditions of heating at 110 ° C. for 15 minutes and further heating at 200 ° C. for 15 minutes to produce the copper-clad laminates of Examples 1-8 and Comparative Examples 1-2.

  Regarding the liquid thermosetting resin composition prepared as described above, the following two evaluations were performed. The results are shown in Table 1.

(Varnish Life)
One day after preparation, the storage stability, particularly the degree of increase in viscosity, was evaluated.
○: Little increase in viscosity was observed Δ: Increase in viscosity was observed ×: Significant increase in viscosity was observed

(110 ° C curable)
The time (minutes) required for the liquid thermosetting resin composition to cure during heating for 15 minutes at 110 ° C. in an oven during the production of the copper clad laminate was measured.

  The following three evaluations were performed on the copper clad laminate produced as described above. The results are shown in Table 1.

(Glass-transition temperature)
The dynamic viscoelastic behavior was measured using a viscoelastic spectrometer (manufactured by SII Nano Technology), and the glass transition temperature (Tg) was determined from the peak value of tan δ.

(Flexural modulus)
A test was conducted in accordance with a general thermosetting plastic test method (JIS K6911), and a flexural modulus was calculated.

(Bending strength)
A test was conducted in accordance with a general thermosetting plastic test method (JIS K6911), and the bending strength was calculated.

  As is apparent from the results in Table 1, (A) a cyanate ester compound having two or more cyanate ester groups in one molecule, and (B) two or more unsaturated double bonds in one molecule. And a radically polymerizable compound having a ring structure formed only from carbon and hydrogen in the molecule and having no hydroxyl group in the molecule, and (C) an epoxy resin having two or more epoxy groups in one molecule In Examples 1 to 8 containing the above, the flexural modulus and flexural strength of the cured product were improved to high values while the glass transition temperature of the cured product was maintained at a high temperature.

  On the other hand, (B) Comparative Example 1 containing no radically polymerizable compound is a cured product in which the thermosetting resin composition does not cure under curing conditions in which heating is performed at 110 ° C. for 15 minutes in an oven and then further heated at 200 ° C. for 15 minutes. Could not be evaluated. (A) The comparative example 2 which does not contain a cyanate ester compound had a relatively low value of the bending elastic modulus and bending strength of the cured product. This is considered because the rigid structure by the (A) cyanate ester compound was not obtained.

  Since the content of the radically polymerizable compound (B) in Example 2 was smaller than that in Example 1, the curability at 110 ° C. was lowered. Since Example 3 had a higher content of the (B) radical polymerizable compound than Example 1, the curability at 110 ° C. was improved. In addition, since the ring structure of the (B) radical polymerizable compound contributed to the stiffening of the cured product, the bending elastic modulus and bending strength of the cured product were not significantly reduced. Rather, the bending strength of the cured product was improved. In Example 4, since the content of (A) cyanate ester compound is larger than that in Example 1, the stiffening structure by (A) cyanate ester compound is increased, and the flexural modulus and bending strength of the cured product are increased. Improved. In Example 5, as in Example 3, the content of the (B) radical polymerizable compound was slightly higher than that in Example 1, and thus the 110 ° C. curability was improved. And since the ring structure of (B) radically polymerizable compound contributed to the rigidification of hardened | cured material, the bending elastic modulus and bending strength of hardened | cured material did not fall.

  In Example 6, compared with Example 1, the type of (A) cyanate ester compound was changed from bisphenol A type to novolac type, but the glass transition temperature and the flexural modulus of the cured product were improved. It was. Example 7 is different from Example 1 in that the type of the (B) radical polymerizable compound is changed from the vinyl ester resin represented by the formula (1) to the vinyl ester resin represented by the formula (2). A slight decrease in the glass transition temperature and the flexural modulus of the cured product was observed. Example 8 is different from Example 1 in that (A) zinc octoate, which is a curing accelerator for a cyanate ester compound, is not blended, and (C) imidazole, which is a curing agent for an epoxy resin, is blended. While an improvement in curability at 110 ° C. was observed, a slight decrease in bending elastic modulus and bending strength of the cured product was observed. From this, it is considered that the (A) cyanate ester compound contributes to the improvement of the bending elastic modulus and bending strength of the cured product rather than the (C) epoxy resin.

Claims (7)

(A) a cyanate ester compound having two or more cyanate ester groups in one molecule;
(B) A radically polymerizable compound having two or more unsaturated double bonds in one molecule and having a ring structure formed only from carbon and hydrogen in the molecule and having no hydroxyl group in the molecule. ,
(C) an epoxy resin having two or more epoxy groups in one molecule, and
(D) a radical polymerization initiator,
A liquid thermosetting resin composition containing The liquid according to claim 1, wherein 10 to 70% by mass of (B) radical polymerizable compound is contained in the total amount of (A) cyanate ester compound, (B) radical polymerizable compound and (C) epoxy resin. Thermosetting resin composition. The liquid thermosetting resin composition according to claim 1 or 2, wherein the radically polymerizable compound (B) is at least one selected from the group consisting of a compound represented by Formula 1 and a vinyl ester resin represented by Formula 2. object.

(E) Liquid thermosetting resin composition of any one of Claim 1 to 3 which further contains the hardening accelerator of a cyanate ester compound. The inorganic filler is contained in an amount of 100 to 200 parts by mass with respect to a total amount of 100 parts by mass of the (A) cyanate ester compound, (B) radical polymerizable compound, and (C) epoxy resin. The liquid thermosetting resin composition according to any one of the above. (G) The liquid thermosetting resin composition according to any one of claims 1 to 5, further comprising a radical reactive diluent.   Copper having a resin insulating layer composed of a cured product obtained by curing the liquid thermosetting resin composition according to any one of claims 1 to 6, and a copper foil layer bonded to the resin insulating layer Tension laminate.