JP5413488B2 - Phenol novolac resin, method for producing the same, epoxy resin composition and cured product using the same - Google Patents

Description

  The present invention relates to a phenol novolak resin useful for various binders, coating materials, laminated materials, molding materials, and the like, a production method thereof, an epoxy resin composition using the same, and a cured product. Phenol novolac that combines low melt viscosity, high glass transition temperature, low moisture absorption, high adhesion, heat resistance, and flame retardancy, especially suitable for epoxy resin curing agents for semiconductor encapsulation, printed circuit board insulation, etc. The present invention relates to a resin, a production method thereof, an epoxy resin composition using the resin, and a cured product.

  Various phenolic polymers, such as phenol novolac resins and phenol aralkyl resins, are used as an epoxy resin curing agent for electronic materials, particularly for semiconductor encapsulation and printed circuit board insulation. However, in recent years, with the miniaturization and thinning of semiconductor packages, the increase in the number of pins, and the high density mounting, higher performance resins are required.

  When used in a single-side sealed package such as BGA (Ball Grid Array), it has excellent performance that the warpage of the package is small. However, in recent semiconductor packages, for example, in the case of BGA, it becomes a finer pitch or a batch sealing type, and it is required that the fluidity is high in addition to the small warpage and the adhesiveness with the substrate surface is good. ing. Further, if the melt viscosity is low, the fluidity and adhesion are improved, and a large amount of filler can be added, which is advantageous in terms of solder heat resistance and water resistance. That is, in order to satisfy the required properties for these encapsulants, the appearance of a low softening point phenol novolac resin that combines low melt viscosity, high glass transition temperature, low hygroscopicity, high adhesion, heat resistance, and flame resistance. It is strongly desired.

  In addition, epoxy resin compositions with excellent water resistance and high adhesiveness at high glass transition temperatures are also desired for interlayer insulation materials for build-up substrates. To achieve this, water resistance and storage stability are inherently improved. An excellent phenolic curing agent having low melt viscosity, high glass transition temperature, low hygroscopicity, high adhesion, heat resistance, and flame retardancy is desired.

  Epoxy resins are often used as resin materials for electronic materials, and various phenol novolac condensates, amines, and acid anhydrides are used as curing agents for the epoxy resins. In particular, as a curing agent for epoxy resin for semiconductor (IC) sealing, phenolic novolak condensates are mainly used in terms of heat resistance and reliability. In recent years, ICs have been highly integrated, packages have become smaller and thinner, and surface mounting methods have been applied, and the sealing material has further improved thermal shock resistance and soldering heat resistance during surface mounting operations. It is requested. A major factor affecting the soldering heat resistance is the hygroscopicity of the sealing resin material. That is, the moisture-absorbing sealing material generates an internal pressure due to vaporization of water at a high temperature during the surface mounting operation, causes internal peeling and package cracks, and has poor soldering heat resistance. Therefore, the phenolic novolak condensate used as an epoxy resin curing agent is particularly required to have low hygroscopicity.

  As a method of reducing the hygroscopicity of the sealing material, there is a method of increasing the amount of filler such as non-hygroscopic silica filled in the sealing resin material as the filler. In this case, if the viscosity of the base resin material is high, the high filling property of the filler is impaired. Therefore, it is desired that the phenolic novolak condensate used as the curing agent has a low viscosity. Further, the sealing material is required to have heat resistance, high strength, toughness, flame retardancy, adhesive strength, and the like. Conventional sealing resin materials using a phenol novolak condensate as a curing agent for the sealing epoxy resin have a relatively high hygroscopicity and are not sufficiently satisfactory from the viewpoint of other physical properties.

Therefore, various phenol novolak condensates have been proposed in order to improve hygroscopicity, heat resistance, adhesion, flame retardancy, and the like. For example, there are novolak condensates using alkylphenols such as o-cresol and novolak condensates using naphthols such as 1-naphthol (for example, Patent Documents 1 to 3). reference). Further, a phenolic compound using di (hydroxypropyl) biphenyl as a phenol condensing agent is disclosed (see Patent Document 4), and a phenol novolak condensate using a bis (methoxymethyl) biphenyl mixture. (Refer to Patent Document 5). Furthermore, an epoxy resin molding material for electronic component sealing (see Patent Document 6) that effectively uses formaldehyde is disclosed.
However, a material having further improved hygroscopicity, heat resistance, adhesive properties, flame retardancy, and the like is desired.

JP 59-230017 Japanese Patent Laid-Open No. 05-078337 JP 05-086156 A JP 05-117350 A Japanese Patent Laid-Open No. 08-143648 JP-A-63-022824

D. W. van Krevelen, Polymer, 16, 615 (1975)

  The object of the present invention is excellent in low melt viscosity, high glass transition temperature, low hygroscopicity, high adhesion, heat resistance, flame retardancy, etc., especially for electrical and electronic industries, for sealing electronic components, and laminate Novel phenol novolak resin suitably used for epoxy resin for materials, epoxidized phenol novolak condensate obtained by epoxidizing this phenol novolak resin, and cured epoxy resin obtained by reacting it with curing agent for epoxy resin Is to provide.

  However, if the introduction rate of the biphenyl group is increased in order to increase the OH equivalent to reduce moisture absorption, the melt viscosity increases. As a result, the fluidity is poor due to an increase in melt viscosity, which causes a molding trouble. When the molecular weight is decreased to lower the melt viscosity, the glass transition temperature is lowered and the curability at the time of molding is lowered. That is, it is considered that it is difficult in principle to achieve both low hygroscopicity, low melt viscosity, curability and high glass transition temperature.

  As a result of intensive studies to obtain a phenol-based curing agent having low moisture absorption, high adhesion, and heat-resistant physical properties of the phenol novolak resin having the aryl group-containing crosslinking group, and having a low melt viscosity, By having both an alkylene type polymer unit and a phenol / formaldehyde polymer unit in the cross-linking group in the molecule, and by setting the ratio of the degree of polymerization of both to a specific range, low melt viscosity, low hygroscopicity, high adhesion, The present invention was completed by finding that a low softening point phenol novolac resin excellent in heat resistance was obtained.

  That is, the present invention provides the following general formula (1):

［式中、Ｒは下記一般式（２−１）：

[ Wherein, R represents the following general formula (2 -1 ):

で示される基であり、更に下記一般式（２−２）：

In a group represented further by the following general formula (2-2):

で示される基、及び／又は下記一般式（３）：

And / or the following general formula (3):

（式中、Ｒ^４は、ヒドロキシル基又は炭素原子数１〜６のアルキル基である）
で示される基を含んでいてもよく、ｍ及びｎは、ｍ／ｎが０．０４〜２０を満たす数であり、また、Ｒ^１、Ｒ^２及びＲ^３は、同一でも異なっていてもよく、それぞれ、ヒドロキシル基又は炭素原子数１から６個のアルキル基であり、ｐ、ｑ及びｒは、それぞれ、０〜２の整数である。］
で示される構成単位を有することを特徴とするフェノールノボラック樹脂に関する。

( Wherein R ⁴ is a hydroxyl group or an alkyl group having 1 to 6 carbon atoms )
And m and n are numbers satisfying m / n of 0.04 to ^20, and R ¹ , R ² and R ³ may be the same or different. Are each a hydroxyl group or an alkyl group having 1 to 6 carbon atoms, and p, q and r are each an integer of 0 to 2 . ]
In about a phenolic novolak resin characterized by it has a structural unit represented.

The present invention also relates to the phenol novolac resin in which the group represented by the general formula (2-1) contains a 4,4′-form.
  Moreover, this invention relates to the said phenol novolak resin whose group shown by the said General formula (2-1) is a mixture of each isomer.
  The present invention also relates to the phenol novolac resin, wherein the m / n is a number satisfying 0.05 to 9.

The present invention also includes phenols, the following general formula (4 -1 ):

（式中、Ｘはハロゲン原子、ヒドロキシル基又は炭素原子数１〜６のアルコキシル基を表す）
で示される化合物、［但し、更に下記一般式（４−２）：

( Wherein X represents a halogen atom, a hydroxyl group or an alkoxyl group having 1 to 6 carbon atoms )
[In addition, the following general formula (4-2):

(Wherein X is as defined above)
And / or the following general formula (5):

（式中、Ｒ ^４ は、前記と同義である）
で示されるベンズアルデヒド化合物も含んでよい。］
及びホルムアルデヒドを、酸触媒の存在下で縮合させることを特徴とする前記フェノールノボラック樹脂の製造方法。

(Wherein R ⁴ has the same meaning as above).
The benzaldehyde compound shown by these may also be included. ]
And the method for producing the phenol novolac resin, wherein the formaldehyde is condensed in the presence of an acid catalyst.

The present invention also relates to an epoxy resin composition containing at least the phenol novolac resin.

Furthermore, the present invention provides a cured product which contains at least the phenolic novolak resin component, and to a cured epoxy resin, wherein the cured product obtained by reacting an epoxy resin.

Full E Nord novolak resin of the present invention, both have polymerized units of an aryl group-containing bridging group resin and a methylene group bridge phenol novolac resin in its molecule, the ratio of both the polymerization degree and both the degree of polymerization at a particular range By having a certain structure, the resin is suitable for an epoxy resin curing agent and has a low melt viscosity, a high glass transition temperature, a low hygroscopic property, a high adhesion property, heat resistance, and flame retardancy. Thereby, it can respond to the latest semiconductor sealing materials such as BGA and can be used as an epoxy resin curing agent.

The phenol novolac resin of the present invention has a total of n polymerization units of the aryl crosslinking group-containing phenol novolak resin represented by the general formula (1), and a total of m polymerization units of the phenol novolak resin containing a methylene crosslinking group. It is a copolymer type low softening point phenol novolac resin, and there is no problem even if it is a block copolymer or a random copolymer. The value of m / n of the polymerization degree of each polymer unit in the general formula (1) Of 0.04 to 20, preferably 0.05 to 9, more preferably 0.09 to 6, and most preferably 0.1 to 2 . Also, even if they do not contain the constituent unit (3), the value of m / n of the polymerization degree of each polymerization unit is from 0.04 to 20, preferably from 0.05 to 9, more preferably 0.09 to 6, most preferably 0.1 to 2 resins.

In full E Nord novolak resin of the present invention, the glass transition temperature is lowered when m / n is more than 20, tended to further flame retardant is undesirably reduced. On the other hand, if m / n is less than 0.04, the melt viscosity increases and the fluidity deteriorates.

The phenols used in the present invention are phenols having at least one hydroxyl group on the benzene ring and optionally substituted with R ¹ , R ² or R ^{3 as} described in the general formula (1). . Here, R ¹ , R ² and R ³ may be the same or different, and a plurality of R ¹ , R ² and R ³ may be the same or different, and each is a hydroxyl group or a carbon atom. 1 to 6 alkyl groups, and each of p, q, and r is a substituent group consisting of integers of 0 to 2. Examples of the alkyl group include linear or branched alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, and these include various isomers. Including.
There is no problem even if these phenols are used alone or in combination of two or more.
Specific phenols include, for example, 1 substituted with an alkyl group having 1 to 6 carbon atoms such as phenol, cresol, ethylphenol, propylphenol, butylphenol, hexylphenol, xylenol, and butylmethylphenol. In addition to dihydric phenols, dihydric phenols substituted with two hydroxyl groups such as catechol, resorcin, hydroquinone and the like can be mentioned, and phenol is particularly preferred.

As the compound that forms a methylene crosslinking group in the present invention, formaldehyde is preferably exemplified. Furthermore, the form of formaldehyde is not particularly limited, but a formaldehyde aqueous solution and a polymer that decomposes in the presence of an acid such as paraformaldehyde and trioxane to formaldehyde can also be used.
A formaldehyde aqueous solution that is easy to handle is preferable, and a commercially available 42% formaldehyde aqueous solution can also be used as it is.

Examples of the aryl group-containing bridging group R used in the present invention include divalent arylene groups represented by the general formulas (2-1) (2-2) and (3).
Examples of such a divalent arylene group include, for example, 4,4′-biphenylylene group, 3,3′-biphenylylene group, 2,2′-biphenylylene group, 2,4′-biphenylylene group, 1,4-xylylene group. Group, 1,3-xylylene group, 1,2-xylylene group and the like.
Among these, 4,4′-biphenylylene group and 1,4-xylylene group are particularly preferable in the present invention.
Specific examples of the aryl group-containing crosslinking group-forming compound for leading to the substituent include compounds represented by the general formulas ( 4-1), (4-2), and (5).
In the general formulas ( 4-1), (4-2), and (5), X is a halogen atom, a hydroxyl group, or an alkoxyl group having 1 to 6 carbon atoms, and R ⁴ is a hydroxyl group or having 1 carbon atom. 6 alkyl groups. Here, as a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example, A chlorine atom is preferable. Examples of the alkoxyl group include linear or branched alkoxyl groups having 1 to 6 carbon atoms such as methoxyl group, ethoxyl group, propoxyl group, butoxyl group, pentyloxyl group, hexyloxyl group, and the like. Also includes isomers. Examples of the alkyl group include those described above.
Specific examples of the compound for leading to the substituent include 4,4′-di (methoxymethyl) biphenyl, 2,2′-di (methoxymethyl) biphenyl, and 2,4′-di (methoxymethyl). Di (alkoxymethyl) biphenyl compounds such as biphenyl, di (such as 4.4′-di (chloromethyl) biphenyl, 2,2′-di (chloromethyl) biphenyl, 2,4′-di (chloromethyl) biphenyl) Di (hydroxymethyl) biphenyl compounds such as halogenomethyl) biphenyl compounds, 4,4′-di (hydroxymethyl) biphenyl, 2,2′-di (hydroxymethyl) biphenyl, 2,4′-di (hydroxymethyl) biphenyl, etc. 1,4-di (methoxymethyl) benzene, 1,3-di (methoxymethyl) benzene, 1,2-di (methoxymethyl) benzene, etc. Di (halogenomethyl) benzene compounds such as 1,4-di (chloromethyl) benzene, 1,3-di (chloromethyl) benzene, 1,2-di (chloromethyl) benzene, 1,4 Di (hydroxymethyl) benzene compounds such as di (hydroxymethyl) benzene, 1,3-di (hydroxymethyl) benzene, 1,2-di (hydroxymethyl) benzene, benzaldehyde, 2-hydroxybenzaldehyde, 3-hydroxybenzaldehyde And hydroxybenzaldehyde compounds such as 4-hydroxybenzaldehyde, and alkylbenzaldehyde compounds such as 2-methylbenzaldehyde, 3-methylbenzaldehyde, and 4-methylbenzaldehyde.
These isomers can be used alone or in combination, but it is preferable to use them as a mixture of isomers.
More preferably, it is an isomer mixture of a biphenylylene compound and / or a xylylene compound.
In the isomer mixture of the biphenylylene compound and / or the xylylene compound, it is most preferable that the 1,4-isomer and the 4,4′-isomer contain at least 50 mol% or more.
However, in the case of using a mixture, it is preferable to use 1,4-xylylene groups at a mixing ratio of 20 to 50 mol% with respect to 1 mol of 4,4′-biphenylylene groups.

[Production Method of Low Softening Point Phenol Novolak Resin]

The method for producing a low softening point phenol novolak resin represented by the general formula (1) comprises n-fold mole of R, that is, an aryl group-containing crosslinking group-forming compound with respect to a certain amount of phenol in the presence of an acid catalyst. , M-fold moles of formaldehyde can be added simultaneously to carry out the condensation reaction in one stage.
In this case, the phenol is preferably used in an amount of 2 to 10 times mol, more preferably 3 to 6 times mol, and still more preferably 4 mols or more relative to a total of 1 mol of the aryl group-containing crosslinking group-forming compound and formaldehyde. At the same time, the reaction between phenols and formaldehyde is preferentially carried out at a low reaction temperature (for example, around 100 ° C.) to form a phenol novolac resin mainly containing low molecular weight methylene crosslinking groups, and then the temperature is increased or the catalyst is increased. Thus, it is preferable to employ a system in which a methylene crosslinking group-containing phenol novolak resin, an aryl group-containing crosslinking group-forming compound and phenols are reacted.
The acid catalyst to be used is not particularly limited, and known acids such as hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid and other inorganic acids, paratoluenesulfonic acid and other organic acids may be used alone or in combination of two or more. Of these, sulfuric acid, succinic acid or paratoluenesulfonic acid is particularly preferred.
The temperature of the condensation reaction is 50 to 120 ° C., preferably 80 to 110 ° C. as a low temperature condition, and the reaction temperature at the time of temperature rise is 130 to 230 ° C., preferably 150 to 200 ° C.
The time for the condensation reaction varies depending on the reaction temperature and the type and amount of the catalyst used, but is about 1 to 24 hours.
The reaction pressure is usually carried out under normal pressure, but there is no problem even if it is carried out under slight pressure or reduced pressure.
A phenol novolak resin having a high molecular weight and a high melt viscosity when the amount of phenols used is less than 2 moles relative to 1 mole of the total of the aryl group-containing crosslinking group-forming compound and formaldehyde. However, there are cases where it can only be obtained, which is not preferable.

Therefore, the low softening point phenol novolak resin of the present invention is a two-stage condensation reaction in which phenols and formaldehyde are condensed in advance in the presence of an acid catalyst, and then an aryl group-containing crosslinking group-forming compound of R is added and condensed. Can also be manufactured. In such a two-stage condensation reaction, phenols can be newly added in the second-stage reaction. In this case as well, it is preferable to use an excess of phenols as in the case of the one-stage reaction. For example, in the first stage reaction, phenols are present in an amount of 2.5 moles or more, more preferably 3.3 to 10 moles per mole of formaldehyde, and an aryl group-containing crosslinking group is added in the second stage reaction. More preferably, the compound and the phenols are prepared in a total of 1 to 2 stages of the aryl group-containing crosslinking group-forming compound and formaldehyde in a total amount of 1 mole, and the phenols to be charged in a total of 1 to 2 stages are 3 moles or more. It is important to use in the range of 3.3 to 10 mol.
When such a two-stage condensation reaction is carried out, the degree of polymerization of each polymer unit of the aryl group-containing cross-linking group type phenol novolak resin and the methylene cross-linking group-containing phenol novolak resin, that is, the distribution of n and m becomes narrow, and the molecular weight is controlled. Is easy for the purpose of the present invention, and a polymer having a desired melt viscosity is easily obtained.
An example of a two-stage condensation reaction is shown in the following reaction formula.

The two-stage condensation reaction can be carried out according to the one-stage condensation reaction conditions.
The amount of the acid catalyst used in the one-stage condensation reaction and the two-stage condensation reaction varies depending on the type of the acid catalyst, but in the case of oxalic acid, about 0.1 to 2.0% by mass of sulfuric acid, In the case of para-toluenesulfonic acid, about 0.02 to 0.1% by mass should be used. In particular, when a two-stage condensation reaction is performed, it is preferable to use sulfuric acid or paratoluenesulfonic acid when the second-stage aryl group-containing crosslinking group is reacted with phenols and a methylene crosslinking group phenol novolac resin. The reaction temperature is not particularly limited, but is preferably set in the range of about 60 to 160 ° C. More preferably, it is 80-140 degreeC.

After the condensation reaction in the presence of an acid catalyst, the unreacted phenols and the acid catalyst are removed, whereby the low softening point phenol novolak resin of the present invention can be obtained.
As a method for removing phenols, a method is generally used in which heat is applied under reduced pressure or while blowing an inert gas to distill the phenols out of the system. The removal of the acid catalyst includes a method such as washing with water.

  In the production method of the low softening point phenol novolak resin of the present invention, the amount of the starting phenols, the aryl group-containing cross-linking group forming compound and formaldehyde is controlled, and the reaction conditions are set as described above to obtain the desired A resin having a melt viscosity at 150 ° C. can be obtained.

  The low softening point phenol novolak resin of the present invention has a structure in which a polymer unit of an aryl group cross-linked phenol novolak resin and a methylene cross-linked phenol novolak resin is present in a specific ratio in the molecule, and has a low melt viscosity and a high glass It is suitable as a raw material for epoxy resins having a transition temperature, low moisture absorption, high adhesion, heat resistance, and flame retardancy.

  Furthermore, the low softening point phenol novolac resin of the present invention can be widely used for applications such as binders, coating materials, laminates, molding materials, etc., but particularly has a low melt viscosity and a high glass transition temperature, low moisture absorption, and high adhesion. In particular, it is suitable for epoxy curing agents for semiconductor encapsulation, printed circuit board insulation, and the like because it has heat resistance, heat resistance, and flame retardancy.

[Hardened epoxy resin]
The low softening point phenol novolac resin of the present invention can be used as an example of a curing agent for epoxy resin. The cured epoxy resin can be obtained by mixing a phenolic polymer, an epoxy resin and a curing accelerator and curing them in a temperature range of 100 to 250 ° C.

  Examples of the epoxy resin include glycidyl ether type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, triphenolmethane type epoxy resin, biphenyl type epoxy resin, and glycidyl. Examples thereof include an epoxy resin having two or more epoxy groups in the molecule, such as an ester type epoxy resin, a glycidylamine type epoxy resin, and a halogenated epoxy resin. These epoxy resins may be used alone or in combination of two or more.

(Curing accelerator)
As a hardening accelerator, the well-known hardening accelerator for hardening an epoxy resin with a phenol type hardening | curing agent can be used. Examples of such curing accelerators include organic phosphine compounds and their boron salts, tertiary amines, quaternary ammonium salts, imidazoles and their tetraphenylboron salts, and among them, curability and moisture resistance. From this point, triphenylphosphine and 1,8-diazabicyclo (5.4.0) undecene-7 (DBU) are preferable. In order to achieve higher fluidity, a heat-latent curing accelerator that exhibits activity by heating is more preferable, and tetraphenylphosphonium derivatives such as tetraphenylphosphonium and tetraphenylborate are preferable.

(Other additives)
In the epoxy resin composition of the present invention, an inorganic filler, a release agent, a colorant, a flame retardant, a low stress agent, or the like can be added or reacted in advance as necessary. Especially when used for semiconductor encapsulation, the addition of inorganic fillers is essential. Examples of such inorganic fillers include amorphous silica, crystalline silica, alumina, glass, calcium silicate, gypsum, calcium carbonate, magnesite, clay, talc, mica, magnesia, barium sulfate and the like. However, amorphous silica, crystalline silica and the like are particularly preferable. The usage-amount of these additives may be the same as the usage-amount in the conventional epoxy resin composition for semiconductor sealing.

  The alkyl type resin of the present invention has an appropriate amount of phenol novolak resin unit, and when used as an epoxy resin curing agent, maintains a high glass transition temperature, low moisture absorption, high adhesion, heat resistance, and flame retardancy. In addition, a low viscosity can be realized.

  The present invention will be specifically described below with reference to examples. In addition, the evaluation method of the phenol novolak resin obtained by this invention is shown.

(1) Measurement of ICI viscosity ICI cone plate viscometer: TOA Kogyo Co., Ltd. MODEL CV-1S was used.
Set the plate temperature of the ICI viscometer to 150 ° C. and weigh about 0.04 g of sample.
Place the weighed resin on the plate, press it with the cone from the top, and leave it for 90 seconds.
The cone is rotated and its torque value is read as ICI viscosity.
(2) Measurement of gel time An epoxy resin and a phenol resin are charged into a test tube so as to have an equivalent of 1: 1, and TPP is weighed so as to be 0.1 wt% with respect to the epoxy, and then charged into a test tube.
A test tube is installed in a gel timer (Toshiba hour meter SFO-304M) in which the oil temperature is set to 150 ° C., and a SUS stir bar is used to stir at one rotation per second.
Initially, the viscosity is low and liquid, but after a certain period of time, the viscosity of the resin rapidly increases and becomes a gel. The time taken during this period is defined as gel time.
The shorter this time, the better the curability.

When phenol novolac resins (Examples and Comparative Examples) synthesized under the conditions shown in Table 1 are used as curing agents, the corresponding epoxy resin is NC-3000 (softening point 60 ° C., epoxy, etc.) manufactured by Nippon Kayaku Co., Ltd. 270 g / eq) of epoxidized biphenyl novolac resin, and triphenylphosphine (sometimes abbreviated as TPP) was used as a curing accelerator.
The low softening point phenol novolac resin of the present invention and the above epoxy resin were blended so that the phenol hydroxyl equivalent weight and the epoxy equivalent ratio were 1: 1, and the TPP catalyst was charged at 1 wt% with respect to the weight of the epoxy resin in the blend. . These were heated to 150 ° C., melted and mixed, vacuum degassed, cast into a 150 ° C. mold (thickness 4 mm), cured at 150 ° C. for 3 hours, and then further 180 ° C. for 5 hours. A molded product was produced by curing.
Test methods for various physical properties of the obtained molded body (cured product) are as follows.
(3) Tg: TMA method (Thermal Mechanical Analysis, thermomechanical analysis method) (heating rate 5 ° C./min)
(4) Water absorption rate: 24 hours boiling method,
(5) Residual carbon ratio Residual carbon and oxygen index are in a proportional relationship, and it is generally said that a resin with high flame retardancy has a high residual carbon ratio (see Non-Patent Document 1). Therefore, it was measured as an index of flame retardancy.
(Measuring method)
The molded body cured with the above composition is cut into 1.5 cm squares, and the weight is measured.
The cut sample is put in a crucible and reduced and fired in an electric furnace at 800 ° C. for 60 minutes.
After cooling, the sample is weighed.
Further, ashing is performed in an electric furnace at 800 ° C. for 2 hours, and the weight is measured.
Obtain the remaining charcoal rate (%) from the following formula.
Residual carbon ratio (%) = (weight after calcination−weight after ashing) / weight of sample × 100

Example 1
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas inlet tube, 376 g (4.0 mol) of phenol, 226 g of 4,4′-dimethoxymethylbiphenyl (abbreviated as 4,4′-BMMB) ( 0.95), 3.6 g (0.05 mol) of 42% formalin aqueous solution, and 0.22 g of 50% sulfuric acid aqueous solution were charged and reacted at 100 ° C. for 1 hour.
Then, it was made to react for 3.5 hours, keeping reaction temperature at 165 degreeC. Meanwhile, the methanol produced was distilled off. After completion of the reaction, the obtained reaction solution was cooled and washed with water three times. The oil layer was separated, and unreacted phenol was distilled off by distillation under reduced pressure to obtain 340 g of a phenol novolak resin (150 ° C. melt viscosity: 90 mPa · s).
Table 1 shows the physical properties of the obtained phenol novolac resin, which were formed into the molded body by the above method.

Examples 2-12 and Comparative Examples 1-5
A phenol novolac resin was obtained according to the method described in Example 1 except that the monomer composition shown in Table 1 was used. The physical properties of each cured product are also shown in Table 1.

(1) Measurement of ICI viscosity ICI cone plate viscometer: TOA Kogyo Co., Ltd. MODEL CV-1S was used.
Set the plate temperature of the ICI viscometer to 150 ° C. and weigh about 0.04 g of sample.
Place the weighed resin on the plate, press it with the cone from the top, and leave it for 90 seconds.
The cone is rotated and its torque value is read as ICI viscosity.

When phenol novolac resins (Examples and Comparative Examples) synthesized under the conditions shown in Table 2 were used as curing agents, the epoxy resin for them was NC-3000 (softening point 60 ° C., epoxy, etc.) manufactured by Nippon Kayaku Co., Ltd. 270 g / eq) of epoxidized biphenyl novolac resin, and triphenylphosphine (sometimes abbreviated as TPP) was used as a curing accelerator.
The low softening point phenol resin of the present invention and the above epoxy novolac resin were blended so that the phenol hydroxyl group equivalent and the epoxy equivalent ratio were 1: 1, and the TPP catalyst was charged at 1 wt% with respect to the weight of the epoxy resin of the blend. . These were heated to 150 ° C., melted and mixed, vacuum degassed, cast into a 150 ° C. mold (thickness 4 mm), cured at 150 ° C. for 3 hours, and then further 180 ° C. for 5 hours. A molded product was produced by curing.
Test methods for various physical properties of the obtained molded body (cured product) are as follows.
(2) Tg: TMA method (Thermal Mechanical Analysis, thermomechanical analysis method) (heating rate 5 ° C./min)
(3) Water absorption rate: 24 hours boiling method,

Example 13
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas inlet tube, 376 g (4.0 mol) of phenol, 4,4′-di (methoxymethyl) biphenyl (hereinafter abbreviated as 4,4′-BMMB). ) 143 g (0.60 mol), 2,4′-di (methoxymethyl) biphenyl (abbreviated as 2,4′-BMMB) 36 g (0.15 mol), 2.2′-di (methoxymethyl) ) Biphenyl (abbreviated as 2,2′-BMMB) 48 g (0.20 mol), 42% formalin aqueous solution 3.6 g (0.05 mol), 50% sulfuric acid aqueous solution 0.22 g were charged at 100 ° C. Reacted for hours.
Thereafter, the reaction was further continued for 3.5 hours while maintaining the reaction temperature at 165 ° C. Meanwhile, the methanol produced was distilled off. After completion of the reaction, the obtained reaction solution was cooled and washed with water three times. The oil layer was separated, and unreacted phenol was removed by distillation under reduced pressure to obtain 335 g of a phenol novolac resin (150 ° C. melt viscosity: 29 mPa · s).
Table 1 shows the physical properties of the cured product obtained by the above method using the obtained phenol novolac resin.

Examples 14-18 and Comparative Examples 6-9
A phenol novolac resin was synthesized according to the method described in Example 13, except that each monomer was used in the component ratio of Table 2. Furthermore, a cured epoxy resin was obtained. Each physical property is shown together in Table 2.

  As is clear from Table 2, the phenol novolak resins obtained in Examples 13 to 18 and the cured products containing the resins have all of low melt viscosity, high glass transition temperature, and low hygroscopicity in a well-balanced manner. In Comparative Examples 6 to 9, any physical property value is decreased.

According to the present invention, it is excellent in low melt viscosity, high glass transition temperature, low hygroscopicity, high adhesion, heat resistance, flame retardancy, etc., especially for electrical and electronic industries, for sealing electronic components, and laminates Novel phenol novolak resin suitably used for epoxy resin for materials, epoxidized phenol novolak condensate obtained by epoxidizing this phenol novolak resin, and cured epoxy resin obtained by reacting it with curing agent for epoxy resin Can be provided.
Moreover, the phenol novolak resin containing a biphenylylene group can also be used as a flame retardant.

Claims (10)

The following general formula ( 1-1 ):

[Wherein, R represents the following general formula (2-1):

In addition, the following general formula (2-2):

And / or the following general formula (3):

(Wherein R ⁴ is a hydroxyl group or an alkyl group having 1 to 6 carbon atoms)
And m and n are numbers satisfying m / n of 0.04 to 6 , and R ¹ , R ² and R ³ may be the same or different. Are each a hydroxyl group or an alkyl group having 1 to 6 carbon atoms, and p, q and r are each an integer of 0 to 2. ]
A phenol novolac resin having a structural unit represented by: The following general formula (1 -2):

[Wherein, R represents the following general formula (2-1):

In addition, the following general formula (3):

(Wherein R ⁴ is a hydroxyl group or an alkyl group having 1 to 6 carbon atoms)
And m and n are numbers satisfying m / n of 0.04 to 9 , and R ¹ , R ² and R ³ may be the same or different. Are each a hydroxyl group or an alkyl group having 1 to 6 carbon atoms, and p, q and r are each an integer of 0 to 2. ]
A phenol novolac resin having a structural unit represented by: The phenol novolak resin according to claim 1 or 2 , wherein the group represented by the general formula (2-1) contains a 4,4'-form. The phenol novolak resin according to claim 3 , wherein the group represented by formula (2-1) is a mixture of isomers. The following general formula (1-3):

[Wherein, R represents the following general formula (2-1):

In addition, the following general formula (2-2):

And / or the following general formula (3):

(Wherein R ⁴ Is a hydroxyl group or an alkyl group having 1 to 6 carbon atoms)
In which m / n is a number satisfying m / n of 0.04 to 20, and R ¹ , R ² And R ³ May be the same or different and are each a hydroxyl group or an alkyl group having 1 to 6 carbon atoms, and p, q and r are each an integer of 0 to 2. ]
A phenol novolak resin, wherein the group represented by formula (2-1) is a mixture of isomers including a 4,4'-isomer. Phenols, the following general formula (4-1):

(Wherein X represents a halogen atom, a hydroxyl group or an alkoxyl group having 1 to 6 carbon atoms)
A compound represented by the formula: [However, the following general formula (4-2):

(Wherein X is as defined above)
And / or the following general formula (5):

(Wherein R ⁴ has the same meaning as above).
The benzaldehyde compound shown by these may also be included. ]
The method for producing a phenol novolac resin according to any one of claims 1 to 5 , wherein the formaldehyde and the formaldehyde are condensed in the presence of an acid catalyst. The following general formula (1-3):

[Wherein, R represents the following general formula (2-1):

In addition, the following general formula (2-2):

And / or the following general formula (3):

(Wherein R ⁴ is a hydroxyl group or an alkyl group having 1 to 6 carbon atoms)
And m and n are numbers satisfying m / n of 0.04 to ^20, and R ¹ , R ² and R ³ may be the same or different. Are each a hydroxyl group or an alkyl group having 1 to 6 carbon atoms, and p, q and r are each an integer of 0 to 2. ]
An epoxy resin composition containing a phenol novolac resin , comprising a structural unit represented by: Hardened | cured material containing the at least 1 resin component chosen from the group which consists of a phenol novolak resin of any one of Claims 1-5 . A cured epoxy resin obtained by reacting the cured product according to claim 8 with an epoxy resin. An epoxidized phenol novolak condensate obtained by epoxidizing the phenol novolak resin according to any one of claims 1 to 5.