JPH0243214A - Epoxy resin with highly reliable fire resistance - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin having excellent heat resistance and highly reliable fire resistance by brominating a specified novolak resin an furthermore reacting it with an epihalohydrin in the presence of an alkali. CONSTITUTION:A fire resistant epoxy rein is prepd. by brominating a novolak resin of the formula, wherein the number of stable o- and p-positions is 1.25-1.45 based on hydroxyl groups and n is substantially 1-8, and furthermore reacting it with an epihalohydrin in the presence of an alkali. A fire resistant epoxy resin having higher heat resistance and higher bromine content than those of fire resistant epoxy resin obtd. from conventional novolak resins can be obtd. This fire resistant epoxy resin can be used in a wide range of fields where high reliability is required, e.g., as insulating materials, laminates, sealing compd., molding materials, composite materials, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flame-retardant epoxy resin that is heat resistant, highly reliable, and has excellent M flame resistance.

[Prior Art] Brominated novolak epoxy resins have excellent heat resistance and flame retardant properties, so they are widely used as encapsulating resins for semiconductors, and have greatly contributed to the development of electronic devices in recent years. There is.

[Problem to be solved by the invention] However, the remarkable progress of electronic devices in recent years has largely been due to the increased integration and density of semiconductors, which has led to even stricter quality requirements for encapsulating resins. It's starting to appear. In particular, the problem of reliability due to high integration and high density has emerged as a demand for higher heat resistance and reduction of free halogen by high temperature boiling extraction method (PCT).

[Means for Solving the Problems J] As a result of intensive studies aimed at improving this reliability, the present inventors have, on the one hand, reduced the low-molecular substance, that is, the dinuclear component, which has an adverse effect on heat resistance. In addition, by reducing the number of novolaks, i.e., novolaks with 11 or more nuclear bodies, it has high heat resistance, and by increasing the number of vacant 0- and p-positions relative to the hydroxyl group, it has no bromine content. The flame retardance has been further improved by increasing the number of layers. I found out what I can get.

On the other hand, we have also found that the above-mentioned high reliability can be achieved even when a cured product is made of a resin in which the epoch characteristic of the resin is as close to the theoretical value as possible.

That is, the present invention provides, on the one hand, a flame-retardant epoxy resin obtained by brominating a novolak-type resin represented by -maximum and reacting it with Zara-ebihalohydrin in the presence of an alkali, in which the vacant 0-position of the novolac-type resin is and a highly reliable flame-retardant epoxy resin obtained from a novolac type resin in which the number of p-positions is 1.25 to 1.45 relative to water m &<, and n is substantially 1 to 8. According to this method, it is possible to obtain an H-flammable epoxy resin that is highly heat resistant and has a high bromine content compared to flame-retardant epoxy resins obtained from conventional novolak-type resins.

On the other hand, the present invention provides a flame-retardant epoxy resin obtained by brominating a novolak type resin represented by -maximum and further reacting shrimp halohydrin in the presence of an alkali, wherein n is preferably 1 or more as an average value. is 1
~3o, and also relates to a resin with an epoxy equivalent of 1 to 4 when the bromine content is reduced to X weight %.

The value of the epoxy ffl (y) is preferably determined by a conventional method of reducing hydrolyzable halogen as a means for imparting reliability. For example, JP-A-60-210615 proposes reducing the amount of hydrolyzable bromine. However, this method is still not sufficient as a means for achieving higher reliability, and it is inevitable that halogens will be liberated from PCT when the resin is actually cured. Surprisingly, however, the cured product using the highly reliable flame-retardant epoxy resin of the present invention has improved reliability by improving To, which is one index of heat resistance, and at the same time has been shown to be resistant to TI-releasing halogens, especially by PCT. The amount of debrominated ions can be significantly reduced. Therefore, by using the flame-retardant boxy resin of the present invention, a cured product with i% reliability can be obtained.

The present invention will be explained in detail below.

Precipitating and separating a phenol novolac resin (softening point 70°C to 120'C) obtained by reacting phenol and formaldehyde in the presence of an acid or alkali catalyst by a known method with a suitable mixed solvent of acetone and isopropyl ether. By this, polymer bodies, that is, components having 11 or more nuclear bodies, are separated. Furthermore, when the resin from which the polymer has been removed is collected and extracted under boiling water, the low molecular weight, or dinuclear component, is extracted into the boiling water, and when the resin is collected from house to house, the polymer is removed. A phenol novolac resin from which low molecular weight substances have been removed is obtained. By repeating this operation once or several times, the number of vacant 0-positions and p-positions relative to hydroxyl groups of the phenol novolac resin as determined by H-NMR is increased to 1.25 to 1.45.

The phenol novolak resin thus obtained is brominated by a known method, for example, the method described in Japanese Patent Publication No. 10635/1983, to obtain a brominated phenol novolak resin solution. The thus obtained brominated phenol novolac resin solution is epoxidized as it is or after recovering the resin if necessary, by a known method in the presence of shrimp halohydrin and an alkali to easily convert the brominated phenol novolac epoxy resin of the present invention (flammable Epoxy resin)
can be obtained.

On the other hand, when the phenol novolac resin from which the high molecular weight and low molecular weight substances have not been removed as described above is similarly brominated and epoxidized to produce a crude brominated phenol novolac epoxy resin (M-flammable 1-boxy resin), A partial reaction occurs between the epoxy group formed during the epoxidation reaction and the phenolic water M group, and a polymer is produced. This is a factor in increasing the epoxy equivalent ω of the Evo4 resin. Therefore, by removing such side reactants from the crude brominated phenolic novolac epoxy resin, the epoxy 5-unit content can be reduced.

Therefore, the crude brominated phenol novolac epoxy resin obtained above is precipitated with a suitable mixed solvent of acetone and isopropyl ether for 11 hours to recover a resin from which relatively high molecular weight components have been removed. The recovered resin is further subjected to an extraction operation under boiling water to extract relatively low-molecular components that have a negative effect on heat resistance into the boiling water.
Collect resin door-to-door. By repeating these operations once or several times, a highly reliable brominated phenol novolak epoxy resin (fl flammable epoxy resin) of the present invention can be obtained.

Regardless of whether the polymer J3 and the low molecular weight substance are removed before or after bromination and epoxidation, the epoxidation is carried out in accordance with a conventional method to remove the brominated novolac type resin and the hydroxyl groups of the brominated novolac type resin. Excess amount of shrimp halohydrin and quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, triethylammonium chloride or alkali metals such as putrium hydroxide, potassium hydroxide, etc. This can be carried out by reacting in the presence of a hydroxide or the like. When a quaternary anenium salt or the like is used, the reaction stops at the stage of the ring-opening addition reaction, so the alkali metal hydroxide is then added to carry out the ring-closing reaction.

In addition, when reacting by adding an alkali metal hydroxide from the beginning, the ring-opening addition reaction and the ring-closing reaction are performed at once.I! obtain.

The proportion of shrimp hydrin used is usually 1 to 50 moles, preferably 3 to 15 moles per 1 mole of hydroxyl group in the brominated novolak resin.

As the shrimp hydrin, epichlorohydrin, epibromohydrin, etc. can be used.

The amount of the alkali metal hydroxide used is usually 0.8 to 1.5 mol, preferably 0.9 to 1.3 mol, based on the water III base J11 of the brominated novolac type resin.
When using class ammonium salt, its usage is usually 0.00T per 1 hydroxyl group needle of brominated novolac type resin.
~1 mol, preferably o, oos ~ 0.5 mol.

The reaction temperature is usually 30 to 130°C, preferably 40 to 80°C.
It is ℃.

It is also possible to allow the reaction to proceed while removing water generated in the reaction from the reaction system. After completion of the reaction, by-produced salts are removed by washing with water, e-filtration, etc., and excess shrimp herohydrin is distilled off.

The highly reliable flame-retardant epoxy resin of the present invention can be used alone or in combination with other epoxy compounds, as well as polyamine curing agents such as aliphatic polyamines, aromatic polyamines, and polyamide polyamines, as well as ordinary epoxy resins. Acid anhydride curing agents such as hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride, phenolic curing agents such as phenol novolak and cresol novolac, Lewis acids such as boron trifluoride or their salts, dicyandiamide, etc. It can be hardened using a hardening agent or the like. Moreover, various compounding agents such as a curing accelerator and an inorganic or organic filler can be added as necessary.

The flame-retardant epoxy resin of the present invention can be used in a wide range of fields requiring high reliability. Specifically, insulating materials, @layer plates, sealing materials, molding materials, composite materials, etc. can be exemplified.

[Example〕 Examples will be described below.

Synthesis Example 1 Phenol novolac resin (Nippon Kayaku (■), softening point 98°C, water
1069/eq) 100g and acetone 200C
Charge C and dissolve. While stirring the acetone solution vigorously, 100 cc of isopropyl ether is added dropwise. After continuing to stir for 30 minutes, the precipitate was removed from house to house.

The P solution was concentrated under reduced pressure to obtain resin 909. The resulting resin was poured into 500 cc of boiling water and stirred vigorously. After stirring for 30 minutes, water was separated by decandation, and the resulting resin was again concentrated under reduced pressure 'Ft% to obtain 80 g of resin (A).

The number of vacant 0-position and p-position relative to the water Wa group of the obtained phenol novolak resin (A> was 1.30.・
Here, the number of empty positions 0 and p for the hydroxyl group is H-N
It was determined by measuring MR. Zunawara, vacant position 0,
It is the ratio of the value obtained by subtracting the number of protons at the m-position from the number of protons at the 0-1m position and the number of protons of the hydroxyl group.

Note that NMR was measured under the following conditions.

NMR conditions NMR: JEOL FTL J NM-GX270 solvent;
DMSO-dS temperature; room temperature Frequency range: 4000Hz, Ifllu: 1
00100 It, 5 td Pulse interval: 2 sec, integration: 20 times Synthesis Example 2 By repeating the series of operations in Synthesis Example 1 using acetone and impropyl ether and the series of operations using boiling water twice, 60 g of resin (B) was obtained. Obtained.

The number of vacant 0-positions and 0-positions relative to the water M group of the obtained phenol novolac resin (B) was determined to be 137 by the same measurement as in Synthesis Example 1.

Example 1 Phenol novolac resin (A) obtained in Synthesis Example 1
(106 g/eQ per hydroxyl group) 53 g and 100 Si of methanol are placed in a four-bottle flask equipped with a thermometer and a stirrer, and dissolved while sucking in nitrogen gas.

To this, 112 g (0.70 mol) of bromine was added at a reaction temperature of 25
Add dropwise at ~30°C. After the bromine dropwise addition was completed, stirring was continued for 30 minutes at the same temperature. Thereafter, a 30% caustic soda aqueous solution was gradually added to neutralize the hydrogen bromide produced as a by-product. After neutralization, this reaction solution was dropped into 5 parts of vigorously stirred water to obtain a granular brominated phenol novolac resin. The granular brominated phenol novolak resin obtained in this way (q) was dissolved in epichlorohydrin 278Sj (3 mol), charged into a reactor equipped with a reflux device, and heated under reduced pressure (100
#ll! Water in the system was removed by azeotropic dehydration using IH (]). After azeotropic dehydration, 42 g of 48% caustic soda aqueous solution was
It dripped in time. During this time, the water contained in the caustic theta aqueous solution and the water produced by the reaction were removed under reduced pressure (1!+OmHg
While azeotropically dehydrating at ~250 amH (]), the reaction temperature was increased to 7.
The temperature was maintained at 5°C to 80°C. After dropping the caustic soda aqueous solution,
The mixture was stirred for an additional 1 hour at the same temperature.

After the reaction is completed, the by-produced salt is filtered, and the P solution is diluted with 10 ml of water.
The reaction solution washed with 0 g of water was concentrated under reduced pressure to drive off excess shrimp[]ruhydrin to obtain brominated phenol novolak resin (A1) 130y. (2) The boxy equivalent was 300, the softening temperature was 93°C, and the bromine content was 40%.

Example 2 Phenol novolac resin (A) obtained in Synthesis Example 1 5
The same operation as in Example 1 was carried out, except that 88 g (0.55 mol) of bromine was used, and 110 g of brominated phenovolac epoxy resin (A2) was obtained. Epoxy equivalent: 263, softening temperature: 85°C, bromine content: 35%
Met.

Example 3 Phenol novolac resin (B
) using 53 g, bromine 120 g (0,75 mol)
Perform the same operation as in Example 1 except for lζ using
Brominated phenolic novolak epoxy resin (B1) 13
Obtained 0g. The epoxy equivalent was 310, the softening temperature was 93°C, and the bromine content was $43%.

Example 4 Phenol novolac resin (B) obtained in Synthesis Example 2 5
The same operation as in Example 1 was carried out except that bromine aag (0,557) was used to obtain 110 g of brominated phenol novolak epoxy resin (B2).

Epoxy equivalent: 260, softening temperature: 85°C, bromine content: 35
%Met.

Comparative Example 1 A commercially available 7-enol novolak resin (Nippon Kayaku ■, softening point 98°C, hydroxyl group) in which the number of vacant 0 and ρ positions relative to the hydroxyl group determined by the same measurement method as in Synthesis Example 1 was 1.22. Brominated phenol novolac epoxy resin (C1) 1099 was obtained by carrying out the same operation as in Example 2, except for using the same W1106).

Epoxy equivalent: 268, softening temperature: 85°C, bromine content: 35
%Met.

Example 5 and Comparative Example 2 7 enol novolak (Nippon Kayakukan, hydroxyl equivalent: 106, softening temperature: 85°C) and cresol novolak epoxy resin (EOCN1020, epoxy equivalent: 201, softening temperature: 71°C) in the proportions shown in Table 1. Example 1, 2, 3.4
Brominated phenolic novolac epoxy resin obtained in (
AI>, (A2), (B1), (82) are blended, 2-
It was cured by heating using methylimidazole as a catalyst.

As Comparative Example 2, the resins obtained in Examples 1 to 4 (AI>,
In place of (Δ2>, (81), and (B2)), the resin (C1) obtained in Comparative Example 1 was used in the proportions shown in Table 1 and heat-cured.

Table 1 shows the glass transition temperature (1'+1) and pressure v-kutzker test (PCT) measurements of the above cured products.

The evaluation conditions for J3, glass transition temperature, and PCT are as follows.

Glass transition temperature thermomechanical measuring device (TMA) Nikumu 1■TM-7
000 Temperature increase rate = 2℃/1lin PCT conditions 5g of cured product (particle size: 60 mesh to 80 mesh) ion exchange water 50g 180℃ x 20 hours Analysis column f [Ion chromatography: Yokogawa Hokushin Electric (Column: 5AX1 ) Eluent: 4mH-NaCo/4mHNatlC
03 removal liquid: 0.05M dodecylbenzenesulfonic acid detection: Electrical conductivity meter Example 6 Phenol novolac resin (5110JJ/e per hydroxyl group)
Q) 53g and 100ItIl of methanol with a thermometer,
Place the mixture in a 4-hole flask with a stirrer and dissolve while blowing nitrogen gas.

To this, 72g (0.45 mol) of bromine was added at a reaction temperature of 25℃~
Add dropwise at 30°C. After the bromine dropwise addition was completed, stirring was continued for 30 minutes at the same temperature. Thereafter, a 30% aqueous sodium hydroxide solution was gradually added to neutralize the mixture.

This reaction solution was dropped into 5 g of vigorously stirred water to obtain a granular brominated phenol novolac resin. The thus obtained granular brominated phenol novolak A4 fat was dissolved in 27 g9 (3 moles) of shrimp [1 lhydrin] and charged into a reactor equipped with a reflux device, under reduced pressure (100 aw + H (
+) to remove water in the system by azeotropic dehydration. After azeotropic dehydration, 42 g of a 48% aqueous sodium hydroxide solution was added dropwise over 6 FR. In this question, the water contained in the caustic soda aqueous solution and the water produced by the reaction were removed under reduced pressure (150 amHg to 250 liters).
The reaction temperature was increased from 75°C to 8°C while azeotropically dehydrating with
It was kept at 0°C. After completing the dropwise addition of the caustic soda aqueous solution, the mixture was stirred at the same temperature for an additional 1 hour.

After the reaction was completed, the by-produced salt was passed through the reactor to drive out excess epichlorohydrin to obtain crude brominated phenol novolak epoxy resin (El) 1099.

The epoxy weight of this resin is 260. Bromine content 301%
Met.

Obtained crude brominated phenol novolac epoxy resin 5
0 g was dissolved in 100 d of acetone, and 100 d of isopropyl ether was added dropwise with vigorous stirring to precipitate the polymer. Separate the precipitate by P using an e-superior agent.

The obtained liquid e is concentrated under reduced pressure to obtain a resin. Further, the obtained resin is poured into boiling water 11 and stirred vigorously for 1 hour to extract low molecular weight substances. After extraction, water was separated by decantation, and the resulting resin was concentrated again under reduced pressure to obtain a resin (Dl). Epoxy ff
l 245. The bromine content was 30.2%.

Example 7 Example 6 except that 88 bromine (0,557 yl) was used.
Perform the same operation as epoxy fli1280.
Crude brominated epoxy resin (E2) with a certain element content of 34.8%
) 105 SJ was further treated in the same manner as in Example 1 to remove polymers and low molecules to obtain resin (D2). Evo 1-Shi Tokou 263. The bromine content was 35.3%.

Example 8 A crude brominated J-boxy resin (E3) with a bromine content of 40.1% and 1302° per epoxy was prepared in the same manner as in Example 6, except that 110 g (0,69-El) of bromine was used. 11
7 LJ was obtained, and the polymer and low molecular weight were removed by the same treatment as in Example 1 to obtain a resin (D3). Epoxy 1280. The bromine content was 40.5%.

Example 9 Example 7 except that 50 d of isopropyl ether was used.
Resin (1) 4) was obtained by carrying out the same operation as above. Epoxy equivalent m 270. The bromine content was 351%.

Example 10 Isopropyl ether 13011! i! Resin (D5) was obtained by carrying out the same operation as in Example 7 except for using the following. Epoxy equivalent: 258. The bromine content was 35.4%.

Example 11 and Comparative Examples 3 to 5 7-enol novolak (Nippon Kayaku ■
, hydroxyl equivalent: 106, softening temperature: 85°C) and cresol novolac epoxy resin ([0CN1020, epoxy equivalent: 201, softening temperature: 11°C), brominated phenol novolak ■boxy resin (Dl) obtained in Examples 6 to 10
, (D2), (D3), (D4), (D5),
It was heat cured using 2-medylimidazole as a catalyst.

As Comparative Examples 3 to 5, crude brominated 7-Nol novolak epoxy resins (・El) and (E
2) and (E3) were blended in the proportions shown in Table 2 and cured by heating.

Table 2 shows the measurements of the glass transition temperature (T(1)) and Bresch 1r- Kutzker-Tess (PCT) of the above cured products.

The glass transition temperature and PCT evaluation conditions are as in Example 5.
is the same as

[Effects of the Invention] According to the present invention, as is clear from Tables 1 and 2, it is possible to obtain a highly reliable cured product that has excellent heat resistance and reduces the time between desorption of Br ions.

Claims (2)

[Claims] (1) In a flame-retardant epoxy resin obtained by brominating a novolac-type resin represented by the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and further reacting epihalohydrin in the presence of an alkali, the vacancies in the novolac-type resin are The number of o-position and p-position is 1.25 to 1 with respect to the hydroxyl group.
．． 45, and a highly reliable flame-retardant epoxy resin obtained from a novolak type resin in which n is substantially 1 to 8. (2) In a flame-retardant epoxy resin obtained by brominating a novolac type resin represented by the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and further reacting epihalohydrin in the presence of an alkali, the average value of n is 1 or more, and the value of the epoxy equivalent (y) when the bromine content is x weight % is y≦17600/(100−X).