JP7268351B2 - Phenolic resin and curable resin composition - Google Patents

Description

The present invention relates to a phenolic resin and a curable resin composition containing the same.

BACKGROUND ART Conventionally, thermosetting resin compositions such as epoxy resin compositions have been used for semiconductor encapsulating materials, printed wiring board materials, fiber-reinforced composite materials, adhesive materials, and the like. For example, in the production of a laminate, which is a material for printed wiring boards, a fibrous base material such as glass cloth is impregnated with a resin varnish containing an epoxy resin, a curing agent, and, if necessary, a solvent, and then dried or heated. A prepreg is obtained by B-stageing, and this is vacuum hot-pressed singly or by stacking a plurality of prepregs. Phenolic resins are known as curing agents.

In recent years, in each of the above applications, the environment in which materials are used has become more severe, and in particular there is a demand for improved heat resistance of materials. A curable resin composition containing a phenolic resin and an epoxy resin is excellent in electrical properties and mechanical properties, but is not necessarily sufficient in heat resistance. A curable resin composition containing a phenolic resin and a bismaleimide compound has been proposed for use in the above laminates from the viewpoint of enhancing heat resistance. For example, as a phenolic resin to be combined with a bismaleimide compound or the like, a novolak-type phenolic resin having an unsaturated group such as an allylphenol novolac resin is known (Patent Document 1).

JP-A-2-110158

However, since unsaturated group-containing phenolic resins combined with conventional thermosetting resins such as maleimide resins contain a large amount of low-molecular-weight components, a large amount of low-molecular-weight components may volatilize during heat curing. Further, when the curable resin composition is cured in combination with a thermosetting resin, the melt viscosity of the curable resin composition during heating may be high and the fluidity may be low. Therefore, a laminate using a conventional curable resin composition containing a phenolic resin having an unsaturated group and a bismaleimide compound generates voids due to volatile components during vacuum heat pressing, or has a high melt viscosity during heating. Since the fluidity is low, there are problems such as a decrease in adhesion between prepregs.

The present inventor has earnestly studied a configuration that can solve the above problems. As a result, the present inventors have found that the above problems can be solved by setting specific ratios of dinuclear or less and tetranuclear or more in a specific phenolic novolac resin having an unsaturated group.

（式中、複数存在するＸはそれぞれ独立にアリル基又はプロペニル基である。ｎは０以上の整数である。） The present invention is based on the above findings, and is a phenol resin represented by the following formula (1),
With respect to the entire phenolic resin, the area ratio by gel permeation chromatography analysis is 10% or more and less than 30% of the component of n = 1 or less, and 10% or more and 30% or less of the component of n = 3 or more. A phenolic resin is provided.

(Wherein, multiple Xs are each independently an allyl group or a propenyl group. n is an integer of 0 or more.)

The phenolic resin of the present invention itself has a low viscosity at room temperature and is easy to handle. In addition, when a resin composition containing a thermosetting resin such as a maleimide compound is formed, volatilization of low-molecular-weight components during curing can be suppressed, and low viscosity can be achieved. Such a curable resin composition effectively prevents a decrease in the yield of the cured product, and when used as a prepreg for a laminated board, has good embeddability of components in a component-embedded substrate.

1 is a gel permeation chromatograph (GPC) analysis chart of the phenolic resin obtained in Example 1. FIG. 2 is a gel permeation chromatograph (GPC) analysis chart of the phenolic resin obtained in Example 2. FIG.

<Phenolic resin>
The phenol resin of the present invention is represented by the following formula (1). As shown in the following formula (1), the phenolic resin of the present invention is a novolak-type phenolic resin.

In formula (1), multiple substituents X are each independently an allyl group or a propenyl group, and preferably an allyl group from the viewpoint of availability.

A novolak-type phenolic resin such as that represented by formula (1) is required to have a low viscosity at room temperature in order to improve handleability.
However, if the phenol resin is made to have a low molecular weight in order to have a low viscosity, the low-molecular-weight component volatilizes during heat curing when it is made into a thermosetting resin composition, and voids and the like tend to occur in the resulting cured product. There is a problem.
On the other hand, when the low-molecular weight component is simply removed to increase the molecular weight, the phenolic resin itself becomes highly viscous and difficult to handle, and when it is made into a thermosetting resin, the fluidity of the resin composition during curing decreases. There is an issue of ease.
As a result of examination by the present inventors, in the novolac-type phenolic resin as shown in formula (1), the ratio of the low molecular weight component and the high molecular weight component is It was newly discovered that it affects liquidity. Fluidity during heat curing is expressed as the minimum melt viscosity of the thermosetting resin composition. Fluidity during heat curing may appear as variation in minimum melt viscosity. In addition, when the curable resin composition contains a solvent, the solvent smoothly volatilizes by using a specific amount of phenolic resin for binuclear or less and tetranuclear or more, and the effect of suppressing variations in the minimum melt viscosity is clear. The inventor thinks that it is easy to appear.
Here, the minimum melt viscosity as used in the present invention means the minimum value of the melt viscosity when measuring the change in the melt viscosity while heating the curable resin composition. The melt viscosity of the thermosetting resin composition is once lowered by heating, and when curing is started by heating, the melt viscosity turns to increase. That is, in the present invention, the lowest melt viscosity means the melt viscosity at the inflection point in the relationship between the heating temperature and the melt viscosity.
Further, the variation in the minimum melt viscosity means the variation when the minimum melt viscosity is measured multiple times for samples of the same lot, for example.
When the minimum melt viscosity is low, the fluidity of the thermosetting resin composition increases during heat curing, and curing defects such as voids can be suppressed. do. As a result, it is possible to prevent deterioration of yield during overheat curing.
For example, a prepreg for a printed wiring board prepared using a thermosetting resin composition containing a novolak-type phenolic resin and a maleimide compound of the present invention exhibits poor curing such as voids after vacuum hot pressing and poor adhesion between prepregs. can be suppressed, and deterioration of yield can be prevented.

As a result of further investigation by the present inventor, the phenol resin of the formula (1), with respect to the entire phenol resin, in the area ratio of gel permeation chromatography analysis n = 1 or less components and n = 3 or more components By making the specific ratio low viscosity at room temperature and easy to handle, it is possible to suppress volatilization of low molecular weight components when it is made into a curable resin composition, and to achieve a low melt viscosity (minimum melt viscosity) at the time of curing, It was found that the variation in the minimum melt viscosity can be suppressed. Specifically, the phenolic resin of the present invention contains 10% or more and less than 30% of components where n is 1 or less, and 10% or more and 30% or less of components where n is 3 or more, in terms of the area ratio.

By setting the area ratio of the component of n=1 or less to less than 30% and the area ratio of the component of n=3 or more to 10% or more, particularly 10% or more and 30% or less, when making a curable resin composition It is possible to moderately reduce low-molecular-weight components during curing. This can reduce volatilization of low molecular weight components during curing. The degree of volatilization of low-molecular-weight components during curing can be evaluated as the weight loss rate of the curable composition during curing. As shown in the examples described later, the curable resin composition containing the phenolic resin of the present invention can effectively suppress voids after vacuum hot pressing also due to the low weight loss rate under vacuum heating conditions.
Further, by setting the area ratio of the component with n=1 or less to 10% or more and the area ratio of the component with n=3 or more to 30% or less, the viscosity of the phenolic resin itself is lowered and handling becomes easy.
Furthermore, the area ratio of the component of n = 1 or less is 10% or more and less than 30%, and the area ratio of the component of n = 3 or more is 10% or more and 30% or less, so that the minimum melt viscosity of the resin composition at the time of curing can be reduced, and further variation in minimum melt viscosity can be suppressed.
For these reasons, the phenolic resin of the present invention is considered to have the above effects.

From the above point of view, in the phenol resin of the present invention, the area ratio of n = 1 or less with respect to the entire phenol resin is more preferably 15% or more and less than 30%, and more preferably 20% or more and 25% or less. is particularly preferred. Further, in the phenolic resin of the present invention, in terms of the area ratio, the component having n = 3 or more is more preferably 15% or more and 30% or less, more preferably 20% or more and 26% or less, relative to the entire phenolic resin. Especially preferred.

Furthermore, in terms of the area ratio of the gel permeation chromatograph analysis, the n = 2 component is preferably 40% or more and 80% or less, more preferably 40% or more and 70% or less, relative to the entire phenolic resin. It is particularly preferable to be 50% or more and 60% or less. When the amount of n = 2 components is within this range, the phenolic resin having the above-described component amount of n = 1 or less and n = 3 or more is easy to produce, has a low viscosity at room temperature, and has a low viscosity at the time of curing. This is because the effects of suppressing volatilization of low-molecular-weight components and reducing the viscosity can be further enhanced.

Components with n=1 or less are mononuclear and dinuclear, and may be hereinafter referred to as binuclear and less components.
A component with n=3 or more may hereinafter also be referred to as a component with 4 or more nuclei.
A component with n=2 may be hereinafter also referred to as a trinuclear body.

As for the bonding position of the substituent X, each of the multiple substituents X can independently substitute at any of the ortho-, meta-, and para-positions relative to the phenolic hydroxyl group. From the viewpoint of the viscosity of the phenol resin and the curability of the resin composition, it is preferable that all the substituents X are bonded to the ortho position.

In the phenolic resin represented by the formula (1), n represents the number of repetitions and is an integer of 0 or more.

Since the phenolic resin represented by the formula (1) is an assembly of molecules having various molecular weights, the value of n can be represented by the average value n'.
The average value n′ is preferably a value within a range that satisfies the above-described component amounts of n=1 or less, n=2 or more, and n=3 or more. Moreover, the average value n' is preferably a value that makes the viscosity at 25° C. the range described below.

The viscosity at 25° C. of the novolak-type phenolic resin represented by formula (1) is preferably 50 Pa·s or less, more preferably 30 Pa·s or less.
Although the lower limit of the viscosity is not particularly limited, it is preferably 0.1 Pa·s or more.

<Method for Producing Novolak-Type Phenolic Resin of the Present Invention>
There are two production methods suitable for producing the phenolic resin represented by the formula (1) of the present invention.
The first is a first step in which a phenol represented by the following formula (2) and formaldehyde or a formaldehyde-generating substance are subjected to a resolization reaction in the presence of a basic catalyst, and the reaction mixture obtained in the first step is subjected to the formula and a second step of further adding the phenol represented by (2) and conducting a novolak reaction in the presence of an acidic catalyst.

式（２）において、Ｘは式（１）と同義である。

In formula (2), X has the same meaning as in formula (1).

A 1st process is demonstrated.
The ratio of the phenol represented by the formula (2) and the formaldehyde or formaldehyde-generating substance reacted in the first step is 1 mol of the phenol represented by the formula (2) to formaldehyde or the formaldehyde-generating substance. Formaldehyde generated from is preferably 1.0 to less than 2.0 mol, more preferably 1.2 to 1.8 mol. When this ratio is equal to or higher than the lower limit of the preferred range, the low molecular weight component can be reduced, and when the ratio is equal to or lower than the upper limit of the preferred range, the high molecular weight component can be kept below a certain level. A phenolic resin is obtained.
The amount of the basic catalyst to be used is not limited, but is preferably 0.1 to 1.5 mol per 1 mol of the phenol represented by the chemical formula (2), and 0.2 A ratio of ~1.0 mol is more preferred. When this ratio is equal to or higher than the lower limit of the preferred range, the reaction proceeds easily and the desired composition is easily obtained. .
Although the reaction temperature is not limited, it is preferably about 10 to 80°C, more preferably 20 to 60°C. When the temperature is 10°C or higher, the reaction proceeds easily and the desired composition can be easily obtained. By setting the temperature to 80° C. or lower, it becomes difficult to increase the molecular weight and the control of the resol-forming reaction becomes easy. Although the reaction time is not limited, it is preferably 0.5 to 24 hours, more preferably 3 to 12 hours.

Phenols represented by the formula (2) used in the first step are not particularly limited, but allylphenol, propenylphenol and the like can be preferably mentioned. Among these, allylphenol is preferred from the viewpoint of availability. These phenols may be used singly or in combination of multiple types.

As the formaldehyde used in the first step, formaldehyde in an aqueous solution can be preferably used. Compounds that generate formaldehyde, such as paraformaldehyde, trioxane, and tetraoxane, can be suitably used as the formaldehyde-generating substance.

The basic catalyst used in the first step includes alkali metal hydroxides such as sodium hydroxide and lithium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide, ammonium hydroxide, and diethylamine. , triethylamine, triethanolamine, ethylenediamine, hexamethylenetetramine and the like. One basic catalyst may be used alone, or two or more of them may be used in combination.

Next, the second step will be explained.
In the reaction of the second step, preferably, the reaction mixture obtained in the resolization reaction of the first step is neutralized with an acidic compound, the phenol represented by formula (2) is added, and then an acidic catalyst is added. It is preferably done after adding.
Suitable acidic compounds for neutralization include hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, butyric acid, lactic acid, benzenesulfonic acid, p-toluenesulfonic acid and the like. One type of acidic compound may be used alone, or two or more types may be used in combination.

The phenol represented by the chemical formula (2) used in the second step is preferably 5 to 20 mol per 1 mol of the phenol represented by the formula (2) used in the first step, It is more preferably 5 to 15 mol, still more preferably 8 to 12 mol. If the amount of the phenol represented by the formula (2) used is less than the lower limit of the preferred range, there is a disadvantage that the proportion of high molecular weight derived from tetranuclear or higher components increases. There is a disadvantage that the proportion of low molecular weights derived from subnuclear components increases.

The amount of the acidic catalyst used in the second step is preferably 0.001 to 0.07 mol per 1 mol of the phenol represented by the chemical formula (2) used in the first step, A more preferable ratio is 0.0005 to 0.05 mol. When this ratio is equal to or higher than the lower limit of the preferred range, the reaction proceeds easily, and when it is equal to or lower than the upper limit of the preferred range, it becomes difficult to increase the molecular weight and the reaction control becomes easy.
Although the reaction temperature is not limited, it is preferably about 50 to 150°C, more preferably about 80 to 120°C. When the temperature is 50° C. or higher, the reaction proceeds easily, and when the temperature is 150° C. or lower, it is possible to suppress the increase in the molecular weight due to heat generation, thereby facilitating the control of the novolak reaction.
Although the reaction time is not limited, it is preferably 0.5 to 12 hours, more preferably 1 to 8 hours. By adjusting the content to be at least the lower limit of the preferred range, the reaction proceeds sufficiently and the desired composition can be obtained. When the amount is equal to or less than the upper limit of the preferable range, it is possible to suppress the increase in the molecular weight.

Suitable acidic catalysts for use in the second step include hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, butyric acid, lactic acid, benzenesulfonic acid, p-toluenesulfonic acid and the like. One type of acidic catalyst may be used alone, or two or more types may be used in combination.

For the phenolic resin used in the present invention, the novolac-ized reaction mixture obtained in the second step is subjected to post-treatment such as washing with water and concentration under reduced pressure to remove unreacted phenols and catalysts. can be preferably obtained by

Next, the second method will be explained. The second preferred production method is A step in which the phenol represented by the above formula (2) and formaldehyde or a formaldehyde-generating substance are subjected to a novolak reaction in the presence of an acidic catalyst, and the product obtained by distillation and a B step of removing a part of n=1 or less components in.
The ratio of the phenol represented by the chemical formula (2) used in step A to formaldehyde or formaldehyde generated from a formaldehyde-generating substance is 1 mol of the phenol represented by the chemical formula (2) to formaldehyde or formaldehyde Formaldehyde generated from the generating substance is preferably 0.10 to 0.30 mol, more preferably 0.15 to 0.25 mol, still more preferably 0.18 to 0.22 mol. If the amount of the phenol represented by the formula (2) used is less than the lower limit of the preferred range, there is a disadvantage that the proportion of low molecular weight components derived from binuclear components or less increases. There is a disadvantage that the proportion of high molecular weights derived from components above the nucleus increases.

The amount of the acidic catalyst used in step A is preferably 0.001 to 0.07 mol, more preferably 1 mol of the phenol represented by the chemical formula (2) used in step A. is a ratio of 0.005 to 0.05 mol. When this ratio is equal to or higher than the lower limit of the preferable range, the reaction proceeds easily, and when it is equal to or lower than the upper limit of the preferable range, it becomes difficult to increase the molecular weight and the reaction control becomes easy.
Although the reaction temperature is not limited, it is preferably about 50 to 150°C, more preferably about 80 to 120°C. When the temperature is 50° C. or higher, the reaction proceeds easily, and when the temperature is 120° C. or lower, it is possible to suppress the increase in the molecular weight due to heat generation, thereby facilitating the control of the novolak reaction.
Although the reaction time is not limited, it is preferably 0.5 to 12 hours, more preferably 1 to 8 hours. By adjusting the content to be at least the lower limit of the preferred range, the reaction proceeds sufficiently and the desired composition can be obtained. When the amount is equal to or less than the upper limit of the preferable range, it is possible to suppress the increase in the molecular weight.

Acidic catalysts used in step A include hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, butyric acid, lactic acid, benzenesulfonic acid, p-toluenesulfonic acid and the like. One type of acidic catalyst may be used alone, or two or more types may be used in combination.

Then, B process is performed. In step B, distillation removes some of the components with n=1 or less. A thin film distillation method is mentioned as a distillation method. When the thin film distillation method is used, it is preferable to perform vacuum distillation, and the degree of vacuum, temperature, and residence time are controlled to remove a portion of the components with n=1 or less. By optimizing the distillation conditions, the area ratio of gel permeation chromatographic analysis of components of n = 1 (binuclear) or less in the phenol resin after treatment is 10% or more and less than 30%, and n = 3 (4 nuclei). Body) The area ratio of the above components is controlled to 10% or more and 30% or less. The degree of vacuum is 1 Pa or more and 4 Pa or less, and the temperature is 130° C. or more and 155° C. or less so as not to remove excessively high molecular weight components including components with n=1 and n=2 (three nuclei). It is preferable in that the desired composition can be obtained successfully.
The phenolic resin of the present invention can be obtained by the above steps.

<Curable resin composition>

Next, the curable resin composition of the present invention (hereinafter also simply referred to as "the composition of the present invention") will be described. The composition of the present invention contains the phenolic resin of the present invention and a polymerizable compound. The polymerizable compound is preferably a thermosetting resin, and includes compounds having two or more maleimide groups in one molecule (hereinafter simply referred to as "maleimide compounds"), epoxy compounds, and the like. is preferred.

Examples of maleimide compounds include those represented by the following formula (3) or formula (4).

（式中、Ｙは１個の炭素－炭素二重結合を主鎖とする二価の基であり、Ｚは２～４０個の炭素原子を有する二価の基である）

(Wherein, Y is a divalent group having one carbon-carbon double bond as a main chain, and Z is a divalent group having 2 to 40 carbon atoms.)

（式中、Ｙは１個の炭素－炭素二重結合を主鎖とする二価の基であり、ｓは０もしくはそれ以上の値である）

(Wherein, Y is a divalent group having one carbon-carbon double bond as a main chain, and s is a value of 0 or more)

In the above formulas (3) and (4), Y is -CR ¹ =CR ² - (R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms). is preferred. Also, Z can be a cyclic, linear or branched aliphatic hydrocarbon group, aromatic hydrocarbon group or heterocyclic group, or a combination of two or more thereof.
s is preferably 0 or more and 4 or less, more preferably 0 or more and 2 or less.

Specific maleimide compounds include 1,6-bismaleimido-(2,2,4-trimethyl)hexane, 1,6-bismamide-(2,4,4-trimethyl)hexane, N,N'-decamethylene Aliphatic (acyclic) such as bismaleimide, N,N'-octamethylenebismaleimide, N,N'-hexamethylenebismaleimide, N,N'-trimethylenebismaleimide, N,N'-ethylenebismaleimide bis[(2,5-dioxo-2,5-dihydropyrrol-1-yl)methyl]bicyclo[2,2,1]heptane, N,N'-p-phenylenebismaleimide , N,N'-m-phenylenebismaleimide, N,N'-2,4-toluylenebismaleimide, N,N'-2,6-toluylenebismaleimide, N,N'-4,4-diphenylmethane Bismaleimide, N,N'-3,3-diphenylmethanebismaleimide, N,N'-4,4 diphenylether bismaleimide, N,N'-3,3-diphenylether-terbismaleimide, N,N'-4 ,4-diphenylsulfidebismaleimide, N,N'-3,3-diphenylsulfidebismaleimide, N,N'-4,4-diphenylsulfonebismaleimide, N,N'-3,3-diphenylsulfonebismaleimide, N,N'-4,4-diphenylketone bismaleimide, N,N'-3,3-diphenylketone bismaleimide, N,N'-4,4-biphenylbismaleimide, N,N'-3,3- Biphenylbismaleimide, N,N'-4,4-diphenyl-1,1-propanebismaleimide, N,N'-3,3-diphenyl-1,1-propanebismaleimide, 3,3'-dimethyl-N ,N'-4,4-diphenylmethanebismaleimide, 3,3'-dimethyl-N,N'-4,4'-biphenylbismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, bis[4- (3-maleimidophenoxy)phenyl]methane, 1,1-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(3-maleimidophenoxy)phenyl]ethane, 2,2- Bis[4-(3-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]-1 , 1,1,3,3,3-hexafluoropropane, 4,4′-bis(3-maleimidophenoxy)biphenyl, bis[4-(3-maleimidophenoxy)phenyl]ketone, bis[4-(3- Maleimidophenoxy)phenyl]sulfoxide, bis[4-(3-maleimidophenoxy)phenyl]sulfone, bis[4-(3-maleimidophenoxy)phenyl]ether, etc. Those having an aromatic ring structure may also be used. These bismaleimide compounds may be used alone or in combination of two or more.

The content of the maleimide compound in the composition of the present invention is the ratio of the number of equivalents of the allyl group or propenyl group of the phenolic resin represented by the formula (1) of the present invention to the number of equivalents of the maleimide group of the maleimide compound [number of maleimide group equivalents / equivalent number of allyl group/propenyl group] is preferably in the range of 0.80 to 2.00, more preferably 0.80 to 1.60.
When this ratio is 0.80 or more, the heat resistance (glass transition temperature) and expandability (linear expansion coefficient) of the cured product tend to be sufficient, which is preferable. In addition, when this ratio is 2.00 or less, it becomes difficult to handle due to poor fluidity, which is a problem of conventionally known bismaleimide compounds, and hardening at low temperature is not easy, and can be obtained. This is preferable because problems such as brittleness caused by a decrease in the toughness of the cured product are less likely to occur.

The functional group equivalent number such as maleimide group equivalent number and allyl group/propenyl group equivalent number is B/ A ([B×C/100]/A when the purity of the compound is C%). That is, functional group equivalents such as maleimide group equivalents and allyl group equivalents represent the molecular weight of a compound per functional group, and the number of functional group equivalents refers to the number of functional groups (equivalent number).

The composition of the invention can contain a radical polymerization initiator. Examples of such radical polymerization initiators include organic peroxides such as acyl peroxides, hydroperoxides, ketone peroxides, peroxides having a t-butyl group, and peroxides having a cumyl group. be able to. For example benzoyl peroxide, parachlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, capryl peroxide, lauroyl peroxide, acetyl peroxide, bis(1-hydroxycyclohexyl peroxide), Hydroxyheptyl peroxide, t-butyl hydroperoxide, p-methane hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide (sometimes abbreviated as DCPO), 2,5- Dimethyl-2,5-di(t-butyl peroxide)hexane, 2,5-dimethylhexyl-2,5-di(peroxybenzoate), t-butyl perbenzoate, t-butyl peracetate, t-butyl per Organic peroxides such as octoate, t-butyl peroxyisobutyrate, di-t-butyl-di-perphthalate can be mentioned, and these can be used alone or in combination of two or more. be able to. When a radical polymerization initiator is used, the amount added is preferably 0.01 parts by mass or more and 8 parts by mass or less, preferably 0.5 parts by mass, relative to 100 parts by mass of the phenolic resin of the present invention in the composition of the present invention. 6 parts by mass or less is more preferable.

The composition of the present invention may contain a solvent, and the solvent in that case includes alcoholic solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as cyclohexanone; ether solvents such as tetrahydrofuran; aromatic solvents such as toluene, xylene, mesitylene; nitrogen atom-containing solvents including amide solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone; sulfur atom-containing solvents including sulfoxide solvents such as sulfoxide; and ester solvents such as ethyl acetate and γ-butyrolactone. Among these, methyl ethyl ketone, propylene glycol monomethyl ether, dimethylformamide, dimethylacetamide, and the like are preferable because they are highly volatile and hardly remain as a residual solvent during prepreg production.

The amount of the solvent is preferably such that the concentration of the solid content of the composition of the present invention is 15 to 100% by mass, more preferably 20 to 90% by mass.

Moreover, the composition of the present invention may contain other optional ingredients. As such optional components, depending on the application of the composition of the present invention, additives such as fillers, imidazole compounds for curing acceleration, coupling agents, pigments, and dyes can be suitably used. Solvents such as organic solvents can also be used.

As fillers, either organic fillers or inorganic fillers can be used. Examples of inorganic fillers that can be used include amorphous silica, crystalline silica, alumina, calcium silicate, calcium carbonate, talc, mica, and barium sulfate. It is particularly preferred to use amorphous silica and crystalline silica. Although the particle size of the inorganic filler is not particularly limited, it is preferably 0.01 μm or more and 150 μm or less in consideration of the filling rate. Although there is no particular limitation on the mixing ratio of the inorganic filler, the ratio of the inorganic filler to the solid content of the composition of the present invention is preferably 70% by mass or more and 95% by mass or less, and 70% by mass or more and 90% by mass. More preferably: By setting the mixing ratio of the inorganic filler within this range, the water absorption rate of the cured product of the composition is less likely to increase, which is preferable.

The amount of the phenolic resin of the present invention in the composition of the present invention varies depending on the application of the composition of the present invention. It is preferably 10% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 60% by mass or less in the components excepted. Further, for example, when the composition of the present invention contains a filler, the amount of the resin of the present invention is preferably 5% by mass or more and 25% by mass or less of the components excluding the solvent in the composition of the present invention. It is more preferable that the content is at least 20% by mass or less.

The total amount of the components other than the phenol resin, maleimide compound, radical polymerization initiator and filler (excluding the solvent) in the composition of the present invention varies depending on the application of the composition of the present invention. In general, it is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less, relative to the resin of the present invention.

In order to prepare the composition of the present invention, for example, the phenol resin and maleimide compound of the present invention, a radical polymerization initiator, an inorganic filler, a solvent, other additives, etc. added as necessary are mixed in a mixer or the like. to mix evenly. When no solvent is used, the mixture may be kneaded in a molten state using a kneader such as a heating roll, a kneader, or an extruder, cooled and, if necessary, pulverized.

A cured product of the composition of the present invention can be suitably obtained by a conventional heat treatment. For example, the heat treatment is affected by the presence or absence of a radical polymerization initiator or curing accelerator, preferably 150 to 280 ° C., more preferably 150 to 250 ° C., preferably 1 to 24 hours, more preferably 1 to 24 hours. It is preferable to carry out the reaction for 12 hours under normal pressure or under pressure using an autoclave or the like.

Also, the composition of the present invention can be uniformly dissolved in the above known solvent to produce a varnish solution. A porous glass substrate such as glass, glass fiber, paper, aramid fiber, or the like is coated or impregnated with the varnish solution, and then heat-treated (semi-cured) to produce a printed circuit board prepreg. Further, a laminate having a matrix resin formed using the composition of the present invention is preferably obtained by laminating a plurality of the obtained prepregs for printed circuit boards and, if necessary, curing them by heat treatment while applying pressure. can be manufactured to
Also, a laminate or prepreg can be obtained by laminating metal foil on one or both sides thereof and performing heat treatment while applying pressure as necessary to obtain a metal-clad laminate. This metal-clad laminate can be suitably used as a printed wiring board by forming a circuit pattern by etching.

The resin of the present invention represented by the formula (1) and the maleimide composition using the same are not particularly limited, but can be suitably used as a sealing material for sealing semiconductor elements. For example, after a lead frame or the like having the semiconductor element mounted thereon is placed in a metal cavity, the maleimide composition is molded by a molding method such as transfer molding, compression molding or injection molding, and heated at a temperature of about 120°C to 300°C. A semiconductor device can be suitably obtained by curing the composition by treatment or the like.

The resin of the present invention represented by the above formula (1) and the composition of the present invention containing the same are used for encapsulation of semiconductor devices, taking advantage of the heat resistance of the cured product, low melt viscosity, stable physical properties during curing, and the like. In addition to electrical and electronic component applications such as sealing materials and printed wiring board materials, it can be used as structural materials, adhesives, paints, and the like. In particular, the resin of the present invention and the composition of the present invention make use of the heat resistance and the above properties, and are used in parts that are used under high temperatures, such as electronic parts related to automotive semiconductors and electronic parts used in display devices that use high voltage. , large batteries, and the like.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Manufacturing and evaluation of phenolic resin)
The methods for measuring the properties used in the examples below are shown below.
(1) Viscosity The viscosity of the phenolic resin was measured using a TVH-type E-type viscometer manufactured by Toki Sangyo Co., Ltd.
(Measurement condition)
Measurement temperature: 25°C
Sample volume: 1.2 mL
(2) Resin composition
[Area ratio (area %) of binuclear or less, trinuclear and tetranuclear]
By the following gel permeation chromatography (GPC) analysis, the area ratios (area %) of binuclear or less, trinuclear, and tetranuclear or more isomers were calculated using analysis software Empower3 Waters. In the calculation of the area ratio (area %) of binuclear or less, trinuclear, and tetranuclear or more, the linear portion before and after the peak derived from each nucleus is taken as the baseline (0 value), and the peak interval of each component separated the peaks by vertical cuts at the lowest points (see FIGS. 1 and 2). The area ratios (area %) of the obtained binuclear or less, trinuclear, and tetranuclear or more bodies were defined as the composition ratios of binuclear or less, trinuclear, and tetranuclear or more.
Equipment used: Waters Alliance 2695 (gel permeation chromatography analysis) Columns: The following five SHODEX columns were connected in series from upstream to downstream in the following order.
KF-804 x 1
KF-803 x 1
KF-802.5 x 1
KF-802 x 1
KF-801 x 1
In addition, one KF-G manufactured by SHODEX was used as a guard column.
Column oven temperature: 40°C
Solvent: Tetrahydrofuran (THF)
Flow rate: 1.00 mL/min Detector: Waters 2487 Dual λ Absorbance Detector
Detection wavelength: 254 nm
As an example, a gel permeation chromatograph (GPC) analysis chart of the phenolic resin A obtained in Example 1 is shown in FIG. A gel permeation chromatograph (GPC) analysis chart of the phenolic resin B obtained in Example 2 is shown in FIG. (1), (2), and (3) in FIGS. 1 and 2 are the peaks derived from binuclear or less, trinuclear, and tetranuclear, respectively.
(3) Allyl group equivalent It was obtained by equivalent measurement according to JIS K0070.

[Example 1]
100.5 g (0.75 mol) of o-allylphenol and 80.36 g (1.125 mol) of 42% by mass formalin were placed in a 2 L glass flask equipped with a thermometer, a feed/distillation outlet, a condenser and a stirrer. , and 120 g (0.75 mol) of a 25% by mass sodium hydroxide aqueous solution as a basic catalyst were added and reacted at 50° C. for 4 hours to perform a resol formation reaction in the first step. The reaction mixture was cooled to 40° C. and neutralized by adding 109.50 g (0.75 mol) of 25 mass % hydrogen chloride to obtain a reaction mixture. Next, 1005.00 g (7.50 mol) of o-allylphenol and 1.01 g of oxalic acid as an acidic catalyst were added to the reaction mixture, and the mixture was reacted at 100° C. for 8 hours to carry out the novolak reaction in the second step. . The resulting reaction mixture was cooled to 95° C. and washed with 754 g of pure water at the same temperature. After washing with water, the temperature was raised to 160° C. and vacuum steaming treatment was performed to remove unreacted components, thereby obtaining phenol resin A.

[Example 2]
600 g (4.48 mol) of o-allylphenol, 63.26 g (0.886 mol) of 42% by mass formalin, and 6.00 g of oxalic acid was added as an acidic catalyst and reacted at 100° C. for 8 hours to carry out a novolak reaction. The resulting reaction mixture was cooled to 95° C. and washed with 754 g of pure water at the same temperature. The washed resin was sent to a thin-film distillation facility at 150° C. under the conditions of a feed amount of 3.33 g/min, and the pressure was reduced at a degree of vacuum of 2.67 Pa to remove binuclear components or less to obtain phenol resin B. .

[Comparative Example 1]
600 g (4.48 mol) of o-allylphenol, 160 g (2.24 mol) of 42% by mass formalin, and an acidic catalyst were placed in a 1000 L glass flask equipped with a thermometer, a feed/distillate outlet, a condenser and a stirrer. 6.00 g of oxalic acid was added as a solution and reacted at 100° C. for 8 hours to carry out a novolak reaction. The resulting reaction mixture was cooled to 95° C. and washed with 754 g of pure water at the same temperature. After washing with water, the temperature was raised to 160° C. and vacuum steaming treatment was performed to remove unreacted components, thereby obtaining phenol resin C.

[Comparative Example 2]
A phenol resin D was obtained in the same manner as in Example 1, except that 71.43 g (1.00 mol) of 42% by mass formalin was used.

[Comparative Example 3]
For the resin after water washing in Example 2, the phenolic resin was produced in the same manner as in Example 2 except that the temperature of the thin film distillation equipment was 160 ° C., the feed rate was 3.04 g / min, and the degree of vacuum was 0.67 Pa. got E.

[Comparative Example 4]
Phenol resin F was obtained in the same manner as in Comparative Example 1, except that 64 g (0.896 mol) of 42% by mass formalin was used.

The physical properties of the phenolic resins A to F obtained in Examples and Comparative Examples were evaluated by the methods described above. The results are listed in Table 1.

(Manufacturing and evaluation of curable resin composition)
[Examples 5 and 6 and Comparative Examples 5 to 8]
Bisphenol A diphenyl ether bismaleimide (BMI-4000 manufactured by Daiwa Kasei Kogyo Co., Ltd., maleimide group equivalent 285 g / eq) as a maleimide compound, and phenol resins A to F obtained in Examples 1 and 2 and Comparative Examples 1 to 4, respectively, A varnish was prepared by blending dicumyl peroxide (Percumyl D manufactured by NOF Corporation, purity: 99.9% by mass) as a radical polymerization initiator and methyl ethyl ketone as a solvent in the proportions shown in Table 2. The resulting varnish was heated to an internal temperature of 50° C., and the pressure was reduced to distill off methyl ethyl ketone to obtain a curable resin composition.
The curable resin compositions were evaluated by the following methods. Table 2 shows the results. In Table 2, the minimum melt viscosity is the average value of two measurements.

(1) Minimum Melt Viscosity A curable resin composition was placed in a rheometer, and the minimum melt viscosity of the curable resin composition was measured under the following conditions.
Apparatus: MCR-102 (manufactured by Antonpaar)
Jig: φ25 parallel plate Frequency: 10Hz
Heating rate: 3°C/min

(2) Variation in Minimum Melt Viscosity The minimum melt viscosity was measured twice for each sample by the method of (1). Variation in minimum melt viscosity in two measurements was determined by standard deviation. A standard deviation of less than 20% was evaluated as ◯, and a standard deviation of 20% or more was evaluated as x.

(3) Thermal weight loss (i) Bisphenol A diphenyl ether bismaleimide (BMI-4000 manufactured by Daiwa Kasei Kogyo Co., Ltd., maleimide equivalent: 285 g/eq) as a maleimide compound, and phenol resins A and B obtained in Examples and Comparative Examples, D and F were blended at an equivalent ratio of 1:1 and melt-mixed at 160°C to obtain a sample.
(ii) About 5 g of the sample was weighed in an aluminum cup, heated in a vacuum dryer at 150° C. for 30 minutes under normal pressure and in an air atmosphere, and then the sample was taken out and weighed (weight A (g)).
(iii) (ii) The sample after measurement was heated in a vacuum dryer from room temperature to 200 ° C. over 1 hour and then heated at 200 ° C. for 1 hour, then the sample was taken out and the weight was measured ( Weight B (g)).
(iv) The thermal weight loss rate was calculated based on the following formula. The results are listed in Table 3.
Thermal weight loss rate A (%) = ((sample (g) - weight A (g)) / sample (g) x 100
Thermal weight loss rate B (%) = ((weight A (g) - weight B (g)) / weight A (g) x 100

As shown in Table 1, the phenolic resin of each example itself has a low viscosity and is easy to handle. Further, as shown in Table 2, the maleimide resin composition of each example has a specific composition for each nucleus of the phenolic resin, so that a low melt viscosity during curing can be achieved and the dispersion of the minimum melt viscosity is improved.
Furthermore, from Table 3, the maleimide resin composition using the phenolic resin of the present invention has a low thermal weight loss rate after vacuum drying, and as a result, the total thermal weight loss rate of the thermal weight loss rate A and the thermal weight loss rate B is low. Note that the thermal weight loss rate A at normal pressure and 150° C. assumes, for example, a drying process during the B-stage of the prepreg for printed circuit boards, and the thermal weight loss rate B at 200° C. under vacuum conditions is Assuming a vacuum hot press process when producing a laminate from a prepreg after B-staging, it is preferable that the thermal weight loss rate is low through both processes.

As described above, when the phenolic resin and curable resin composition having a low minimum melt viscosity, suppressed variation, and a low thermal weight loss rate are used in a laminate for a printed wiring board, voids of volatile components are generated in the mounting process. However, it is possible to easily solve the problems that poor connection is likely to occur and that the yield deteriorates due to variations in melt viscosity during curing. Therefore, the phenolic resin and the curable resin composition of the present invention can be applied to thinner substrates, narrower wiring pitches of wiring boards, finer connection parts, higher temperature mounting processes, etc., and can be used industrially. It is clear that the

Claims (6)

A phenol resin represented by the following general formula (1),
With respect to the entire phenol resin, the area ratio by gel permeation chromatography analysis, the component of n = 1 or less is 15 % or more and less than 30%, and the component of n = 3 or more is 10% or more and 30% or less. Yes, phenolic resin.

(Wherein, multiple Xs are each independently an allyl group or a propenyl group. n is an integer of 0 or more.) The phenolic resin according to claim 1, which has a viscosity at 25°C of 50 Pa·s or less. A curable resin composition containing the phenolic resin according to claim 1 or 2. The curable resin composition according to claim 3, containing a maleimide compound. The curable resin composition according to claim 3 or 4, containing a radical polymerization initiator. A cured product obtained by curing the curable resin composition according to any one of claims 3 to 5.

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