JPH0977909A - Flame retardant for thermosetting resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame retardant for a thermosetting resin, which can be stably stored for a long time by using a composition comprising a tribromophenol-modified brominated epoxy resin having a specified molecular weight and a specified weight-average molecular weight. SOLUTION: This flame retardant for a thermosetting resin comprises a tribromophenol-modified brominated epoxy resin being a mixture of compounds represented by formula I (wherein A is -CH2 -, -SO2 -, -O- or-C(-CH3 )2 -, R<1> and R<2> are each a group of formula II or III, provided that they can not be groups of formula II simultaneously; R<3> is H or CH3 , (m) is an integer of 1-4, and (r) is 0 or a positive integer) and having a molecular weight distribution of 1.035 or above and a weight-average molecular weight of 1,600 or below. The upper limit of the molecular weight distribution is desirably 1.08, and the lower limit of the weight-average molecular weight is desirably 1,380.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame retardant suitable for use in a thermosetting resin, a laminated board produced by using the flame retardant, and an electronic / electrical device using the laminated board.

[0002]

2. Description of the Related Art Phosphorus flame retardants and halogen flame retardants are known as flame retardants used in thermosetting resins.

By the way, a flame retardant which is usually used for a thermosetting resin is required to have heat resistance capable of withstanding a heat history received when molding the resin or when using a molded product. Furthermore, when producing a thermosetting resin, it is often the case that a liquid low-polymerized product having a relatively low viscosity is polymerized,
It is difficult to disperse a flame retardant having a large specific gravity in a uniform state and store it for a long time. Therefore, there is a need for a flame retardant that is highly compatible with the resin prepolymer.

However, the phosphorus-based flame retardant has a problem that it is inferior in flame retardancy as compared with the halogen-based flame retardant and inadequate in heat resistance, in addition to insufficient compatibility with resin and water resistance. Have. On the other hand, halogen-based flame retardants generally have problems in compatibility with prepolymers, heat resistance, moldability, and the like, and various improvements have been conventionally made to halogen compounds, which are essential as flame retardant components. For example, in JP-A-59-53523, a general formula:

[0005]

[Chemical 6]

(In the formula, X represents a halogen atom, and a represents 1
To 3, m is 1 to 2, n is an integer of 1 to 2, R ⁴ is 1 carbon atom
~ 4 alkylidene group or alkylene group, R ⁵
Is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms).

Further, Japanese Patent Publication No. 52-16130 discloses that
General formula:

[0008]

[Chemical 7]

(Wherein X is a halogen atom such as chlorine and bromine, R is hydrogen, an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an aromatic or halogen atom such as a cycloalkyl group and a phenyl group, m and m'are 0
To 4 and n and n ′ are integers from 1 to 5 and 1 ≦
n + m ≦ 5, 1 ≦ n ′ + m ′ ≦ 5) have been proposed.

However, the flame-retardant compounds described in JP-A-59-53523 and JP-B-52-16130 are obtained by reacting monoglycidyl ether with 1 mol of dihydroxy compound in an amount of 1 to 3 mol due to the production method. It is a low-molecular compound that can be obtained, and monoglycidyl ether is 2
If it is less than the molar amount, the unreacted phenolic hydroxyl group remains and the heat resistance decreases. Further, when the amount is 2 mol or more, highly reactive monoglycidyl ether remains, and when added or blended with the resin, gelation of the resin liquid or other undesirable uncontrollable side reaction occurs, and the storage stability is high. A fault such as a failure occurs.

Japanese Patent Publication No. 6-49797 proposes a flame retardant which has improved the above problems of the flame retardant halogen compound. This flame retardant has the formula (I):

[0012]

Embedded image

(In the formula, A is --CH _2- , --SO _2- , --O
-Or

[0014]

Embedded image

A group is shown. R ⁶ represents H or CH ₃ group.
Y represents Br, Cl, CH ₃ group or H. m and n
Represents an integer of 1 to 4. s is an average value of 0.1 to
1 mole of the epoxy compound represented by the formula (II):

[0016]

Embedded image

(Wherein R ⁷ represents H or a C _{1 to} C ₄ linear or branched alkyl group. X represents CI, Br or I. q is an integer of 0 to 4 and p is 1). Each of the numbers is from 5 to 5, where 1.80 to 1.99 mol of the halogenated phenol represented by p + q.ltoreq.5 is contained as an essential component.

Although this flame retardant is superior in flame retardancy and storage stability to the above halogen compounds, it can be used in drums and lorries in winter, in extremely cold regions or in regions with relatively low temperatures and large temperature differences. During transportation or storage in a stock tank, turbidity may occur depending on the mode of transportation or storage, and in extreme cases it may solidify. In that case, it can be used if heated and dissolved, but it is difficult to process a large amount, and when it is added and mixed with the thermosetting resin in a turbid or partially solidified state, it is not sufficiently compatible,
The obtained cured resin may deteriorate the electrical properties and mechanical properties, or may have a poor appearance.

[0019]

The present inventor has made various attempts to improve the storage stability of this flame retardant, but in the process, the storage stability and the Δhaze value are correlated, It was found that excellent storage stability can be obtained when the Δhaze value is 20 or less, particularly 10 or less. Further studying this finding, the molecular weight distribution (weight average molecular weight / number average molecular weight) was set to 1. in order to reduce the Δhaze value to 20 or less.
The present invention has been completed by discovering that the weight average molecular weight is 035 or more and the weight average molecular weight is 1600 or less.

[0020]

That is, the present invention provides formula (I):

[0021]

Embedded image

R ³ is H or CH ₃ , m is an integer of 1 to 4,
n is an integer of 1 to 4, r is 0 or a positive integer) and is a mixture of compounds having a molecular weight distribution (weight average molecular weight / number average molecular weight ratio, the same applies hereinafter) of 1.035 or more and a weight. The present invention relates to a flame retardant for a thermosetting resin containing a tribromophenol-modified brominated epoxy resin having an average molecular weight of 1600 or less.

The present invention also provides formula (II):

[0024]

[Chemical 12]

(Wherein A, R ³ , m, n and r are the same as above) and a brominated epoxy resin represented by the formula (II
I):

[0026]

Embedded image

The present invention relates to a flame retardant for a thermosetting resin containing a resin obtained by charging the reaction vessel with tribromophenol represented by and heating the mixture in a nitrogen atmosphere under reduced pressure to start the reaction.

Furthermore, the present invention relates to a flame-retardant laminated plate obtained by laminating paper impregnated with a composition containing the flame retardant of the present invention and a thermosetting resin. Further, the present invention also relates to an electronic / electrical device in which the flame-retardant laminate is incorporated.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The tribromophenol-modified brominated epoxy resin, which is an active ingredient of the flame retardant of the present invention, is represented by the above formula (I), and the brominated epoxy resin of the formula (II) and the formula (II) It can be obtained by reacting III) with tribromophenol under specific conditions.

In the formula (I), A is

[0031]

Embedded image

It is preferable that R ³ is H, and that m and n are all 2-3.

[0033]

[Chemical 15]

It is preferred that R ³ is H, and m and n are all 2.

The resin of formula (I) or formula (II) and formula (I)
The reaction product with II) is a mixture of one end modified with tribromophenol and both ends modified with tribromophenol, and also a mixture of compounds in which r is 0 or a positive integer. Since the upper limit of the weight average molecular weight is 1600, the upper limit of r is 6, usually 4.

The findings that form the basis of the present invention are as described above.
When the Δ haze value is 20 or less, the long-term storage stability is further improved, and therefore the molecular weight distribution is 1.0
It was selected to be 35 or more and a weight average molecular weight of 1600 or less.

The larger the molecular weight distribution, the more difficult it is to solidify, which is preferable. However, the viscosity becomes high and a problem occurs in processing, so that it is preferably 1.08 or less. When it is less than 1.035, it becomes difficult to reduce the Δhaze value to 20 or less.

The weight average molecular weight is 1600 or less. If it is larger than this, the viscosity becomes high, and when it is blended with a thermosetting resin to prepare a laminated plate, impregnation into the paper base material becomes poor and delamination occurs. It will be easier. The preferred lower limit of the weight average molecular weight is naturally determined from the molecular structure, but if it is less than about 1380, it becomes difficult to make the molecular weight distribution 1.035 or more.

The flame retardant of the present invention can be obtained, for example, by reacting a brominated epoxy resin of the formula (II) with tribromophenol of the formula (III). A preferred brominated epoxy resin of the formula (II) is, for example, the following formula (IV)
A mixture of the above.

[0040]

Embedded image

N is 0 or an integer of 1 to 4, and the average value of n as a mixture is 0.15 to 0.42, particularly 0.1.
It is preferably 7 to 0.28. This corresponds to an epoxy equivalent of 375 to 450, especially 380 to 410.

Examples of the tribromophenol represented by the formula (III) include 2,4,6-tribromophenol.

As the reaction conditions, for example, a brominated epoxy resin (II) and tribromophenol (III) are mixed, a tertiary amine is added as a catalyst under a reduced pressure in a nitrogen atmosphere in the presence of a solvent, and the mixture is heated. To start the reaction.
The reaction system is pressurized by heating, but the reaction is carried out for about 3 to 5 hours while maintaining the pressurized heat.

The reaction ratio between the brominated epoxy resin (II) and the tribromophenol (III) is advantageous because a flame retardant having a high bromine content is advantageous.
It is preferable to use 1.5 to 2 mol, particularly 1.7 to 1.95 mol of tribromophenol (III) per 1 mol of I).

Examples of the reaction solvent used include benzene, toluene, xylene, acetone, methyl ethyl ketone and the like. These solvents can also be used as a solvent for the flame retardant. From this point, toluene is particularly preferable.

Then, the reaction system is replaced with nitrogen to create a nitrogen atmosphere, and the pressure is further reduced. It is important to set the nitrogen atmosphere in a decompressed state before starting the reaction in order to obtain a reaction product having a large molecular weight distribution. Reduced pressure is about -0.6 to -0.1
kg / cm ² G, usually preferably about -0.4kg / cm ² G.

The reaction is started by adding a catalyst in a nitrogen atmosphere under reduced pressure and then heating. The catalyst is added after the nitrogen substitution. The catalyst is a tertiary amine, and examples thereof include triethylamine, tributylamine, dimethylaniline, triallylamine, trioctylamine, dimethylbenzylamine, lauryldimethylamine, pyridine, picoline, and quinoline. Therefore, triethylamine and tributylamine are preferable. The catalyst is a brominated epoxy resin of 0.
It is added in the range of 001 to 1% by weight.

The reaction is started by heating to a reaction temperature of 8
The reaction is allowed to proceed at 0 to 150 ° C, preferably 120 to 140 ° C for 3 to 5 hours. Although the pressure in the reaction system rises due to heating to bring it into a pressurized state, the reaction proceeds under the pressurized state. Usually, it is preferably carried out under a pressure of 0.2 to 2.0 kg / cm ² G.

The obtained reaction product, that is, the tribromophenol-modified brominated epoxy resin has a molecular weight distribution of 1.
It has a weight-average molecular weight of 035 or more and 1600 or less.

Weight average molecular weight

[0051]

[Outside 1]

And number average molecular weight

[0053]

[Outside 2]

Is obtained by GPC analysis, and from that value the molecular weight distribution

[0055]

[Outside 3]

Was calculated. These calculations were performed according to the following formulas.

[0057]

[Outside 4]

Area ratio (%) of GPC analysis of each component, ni of each composition = area ratio (%) of each composition / estimated molecular weight of each composition The analysis conditions of GPC are as follows.

Analyzer: SPD- manufactured by Shimadzu Corporation
6A Reagent: 0.5% by weight THF solution.

Temperature: 40 ° C. Injection amount: 50 μl Flow rate: THF 1.0 ml / min Column: One G4000HXL manufactured by Tosoh Corp., G
3000 HXL x 1, G1000HXL x 2 Detector: UV (254 nm) The obtained tribromophenol modified brominated epoxy resin (hereinafter sometimes referred to as "modified brominated epoxy resin") is diluted to obtain a Δhaze value of 20 or less. Make something. The diluent solvent may be the same as or different from the reaction solvent. Examples thereof include methyl ethyl ketone, acetone, and toluene, and methyl ethyl ketone or a mixed solvent of methyl ethyl ketone and toluene is preferable from the viewpoint of solubility.
The solid content concentration is preferably about 60 to 80% by weight.

When diluting, it is important that after the dilution solvent is added, it should be heated once and dissolved to form a uniform solution. If it is not made into a uniform solution, the storage stability becomes poor. A heating temperature of about 80 to 110 ° C is suitable.

In the present invention, the Δhaze value is a value representing the degree of haze used as a standard for evaluating long-term storage stability, and is measured by the following method.

(Haze Value) The reaction product of Production Example 2 described later was stored for a long time and solidified, and used as a seed crystal.
The seed crystal was added to the flame retardant solution prepared in each Production Example and diluted.
Add 00 ppm and store at 5 ° C. for 6 hours. The amount of change in haze immediately after addition of the seed crystal is defined as a Δhaze value. The haze value is DIGITAL HAZE manufactured by Suga Test Machine Co., Ltd.
It was measured by COMPUTER.

When the Δhaze value becomes large, the storage stability becomes poor for a long period of time, particularly for a long period of winter (3 months or more). The Δhaze value of the flame retardant solution that can be used practically (3 months or more) is 20 or less, particularly 10 or less, and more preferably 0 to 5.
A Δhaze value of 30 solidifies in 30 days in winter.

In the present invention, the Δhaze value thus obtained is 2
It is a flame retardant containing a modified brominated epoxy resin solution of 0 or less as a main component, but if desired, other brominated flame retardants, chlorine flame retardants, phosphorus flame retardants, halogen-containing phosphorus flame retardants, and hydroxides. Aluminum, antimony trioxide, antimony pentoxide, inorganic flame retardants such as zinc borate, brominated epoxy resin, tung oil, melamine, melamine isocyanurate, antioxidant, plasticizer, stabilizer, filler, dye, pigment, A solvent or the like can be added.

The flame retardant of the present invention is used by adding it to a thermosetting resin.

The blending amount of the flame retardant of the present invention with respect to the thermosetting resin is usually 2 to 50 parts with respect to 100 parts of the thermosetting resin (parts by weight, the same applies hereinafter). If the blending amount is less than 2 parts, satisfactory flame retardancy cannot be obtained. On the other hand, if the blending amount exceeds 50 parts, not only may there be an unfavorable influence on the physical properties of the resin, but it is also disadvantageous from the economical aspect. .

Examples of the thermosetting resin include phenol resin, unsaturated polyester resin, melamine resin, epoxy resin, silicone resin, urea resin, diallyl phthalate resin, butadiene resin and urethane resin.

The thermosetting resin composition containing the flame retardant of the present invention is used in various applications and fields depending on the respective resin characteristics. For example, it is useful for various molded products, films, laminates, resin-impregnated papers, dyes, adhesives and the like.

Of these, a flame-retardant laminate obtained by impregnating paper with a flame-retardant-containing thermosetting resin composition, laminating the same and then hot-pressing and curing the same has conventionally been delaminated. Although it was difficult to make flame retardant, the use of the flame retardant of the present invention makes it possible to obtain a laminated plate which is free from delamination and has excellent dimensional stability and heat resistance. Such a laminate can be used for a printed circuit board. When used in a printed circuit board, a phenol resin having excellent electrical characteristics is suitable as the thermosetting resin. In that case, kraft paper or the like is used as the paper.

This flame-retardant laminate is incorporated in electronic receivers such as television receivers, video tape recorders, various audio equipments, mobile phones, washing machines, W type air conditioners, etc. to make them flame-retardant. To contribute.

[0072]

EXAMPLES The present invention will be described below with reference to production examples and examples, but the present invention is not limited to these examples.

Production Example 1 680 g (1 mol) of the brominated epoxy resin of the formula (IV) (epoxy equivalent 340) and 612 g of 2,4,6-tribromophenol were placed in a 2-liter autoclave.
(1.85 mol) and 170 g of toluene were charged, the pressure in the autoclave was reduced to -0.6 kg / cm ² G, nitrogen gas was introduced, and then the pressure was returned to atmospheric pressure. After this nitrogen substitution operation was repeated again, after the third substitution, the inside of the autoclave was kept at a reduced pressure of -0.4 kg / cm ² G instead of atmospheric pressure. After adding 8 g of tributylamine as a catalyst, it was heated to start the reaction. When the temperature was raised to 135 ° C., the inside of the autoclave was in a pressurized state of 1.3 kg / cm ² G, and the reaction was carried out under the pressure at a temperature of 135 ° C. for 5 hours. Methyl ethyl ketone was added to the reaction product so that the solid content was 75% by weight, and the mixture was stirred at 80-85 ° C for 1 hour.
The mixture was heated under stirring for an hour to completely dissolve the solid matter, and a uniform flame retardant solution was obtained.

When the obtained reaction product was analyzed by GPC, it was estimated to be a mixture of compounds of the following formulas (A) to (F) (however, (D) to (F) were not detected). Tribromophenol modified brominated epoxy resin,
Molecular weight distribution

[0075]

[Outside 5]

Is 1.015, weight average molecular weight

[0077]

[Outside 6]

Was 1301 and its Δ haze value was 46.2.

[0079]

Embedded image

Production Examples 2 to 10 Brominated epoxy resin (BrEPO) shown in Table 1, 2,
Using 4,6-tribromophenol (TBP) and a catalyst, the reaction was carried out under the reaction conditions shown in the same table to obtain a tribromophenol-modified brominated epoxy resin.

The obtained modified brominated epoxy resin was analyzed by GPC in the same manner as in Production Example 1, and the estimated content ratio of each compound was

[0082]

[Outside 7]

Was examined and the Δhaze value was measured. The results are shown in Table 1.

In Table 1, TBA in the column of catalyst is tributylamine, TEA is triethylamine, and DMBA is dimethylbutylamine.

[0085]

[Table 1]

For reference, a GPC analysis chart of the tribromophenol-modified brominated epoxy resin obtained in Production Example 4 is shown in FIG.

Example 1 Using the reaction product obtained in each Production Example as it was, 20 parts of the reaction product obtained in each Production Example were added to 100 parts of a methanol solution of a phenol resin containing 70 parts of a commercially available phenol resin containing tung oil. Parts and 10 parts of diphenyl cresyl phosphate were added and uniformly dissolved to obtain a resin varnish.
Kraft paper (thickness 1mm, length 150m)
m, width 100 mm) and then pre-dried at 80 ° C. for 20 minutes, and 8 sheets of pre-dried impregnated kraft paper are stacked and heated by a press at 160 ° C., 100 kg / cm ²
It pressed under the conditions of 3 minutes, and produced the laminated board.

The obtained laminated plate having a resin amount of 55% by weight was further treated at 160 ° C. for 3 hours, and flame retardancy and physical properties were evaluated by a predetermined method of UL-94.

The results are shown in Table 2.

[Test Conditions and Evaluation Method] (1) Storage stability of varnish: The state after standing at -20 ° C for 48 hours was visually judged.

(2) Flammability: According to UL-94.

(3) Insulation resistance: After being left for 96 hours under the conditions of 40 ° C. and 92% RH, it was carried out according to JIS C6481.

(4) Solder heat resistance: Appearance after being held at 260 ° C. for 30 seconds is visually judged.

(5) Dimensional stability of laminated plate: 1 at 220 ° C.
The appearance after holding the time is judged with the naked eye.

[0095]

[Table 2]

[0096]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a flame retardant for thermosetting resin which can be stably stored for a long period of time, and a flame retardant laminate obtained by using the flame retardant.

[Brief description of drawings]

FIG. 1 is a GPC chart of a tribromophenol-modified brominated epoxy resin obtained in Production Example 4.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 101/00 C08L 101/00

Claims (12)

[Claims] 1. Formula (I): R ³ is H or CH ₃ , m is an integer of 1 to 4, n is an integer of 1 to 4, r is O or a positive integer, and is a mixture of compounds having a molecular weight distribution (weight average molecular weight). Flame retardant for thermosetting resin containing a tribromophenol-modified brominated epoxy resin having a ratio (number ratio / number average molecular weight) of 1.035 or more and a weight average molecular weight of 1600 or less. 2. The flame retardant according to claim 1, wherein the upper limit of the molecular weight distribution is 1.08. 3. The flame retardant according to claim 1, wherein the lower limit of the weight average molecular weight is 1380. 4. A in the formula (I) is And R ³ is H and m and n are both 2. The flame retardant according to any one of claims 1 to 3. 5. The flame retardant according to claim 1, wherein the thermosetting resin is a phenol resin. 6. The flame retardant according to claim 1, wherein the tribromophenol-modified brominated epoxy resin has a Δhaze value of 20 or less. 7. The flame retardant according to claim 1, wherein the tribromophenol-modified brominated epoxy resin has a Δhaze value of 10 or less. 8. Formula (II): embedded image (In the formula, A is —CH ₂ —, —SO ₂ —, —O— or R ³ is H or CH ₃ , m is an integer of 1 to 4, n is an integer of 1 to 4, r is 0 or a positive integer) and a brominated epoxy resin represented by the formula (III): The flame retardant according to any one of claims 1 to 7, wherein a resin obtained by charging tribromophenol represented by the formula (3) into a reactor and starting the reaction by heating under reduced pressure in a nitrogen atmosphere is used. 9. A flame-retardant laminated sheet obtained by laminating papers impregnated with the composition comprising the flame-retardant agent according to claim 1 and a thermosetting resin. 10. The laminate according to claim 9, which is a printed circuit board. 11. An electronic / electrical device in which the flame-retardant laminate according to claim 9 is incorporated. 12. The electronic / electrical device according to claim 11, which is a television receiver, a video tape recorder, an audio device, or a mobile phone.