JP2005082668A - Flame retardant, method for producing the same, and resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a convenient flame retardant produced in high productivity and having stabilized properties; to provide a method for producing the flame retardant; and to provide a resin composition free from a halogenated epoxy resin and an antimony compound such as antimony trioxide, and providing a cured product having excellent flame retardancy, moldability and reliability. <P>SOLUTION: The flame retardant comprises a complex oxide of molybdenum and zinc, and has 0.1-10 μm average particle diameter and 1-20 m<SP>2</SP>/g specific surface area. The molar ratio of the molybdenum to the zinc is (10/90)-(90/10). The method for producing the flame retardant comprises (1) a step for feeding a raw material powder in which the molar ratio of the molybdenum to the zinc is regulated so as to be (10/90)-(90/10) with a carrier gas to a reaction chamber, (2) a step for oxidizing the fed raw material powder in the reaction chamber to form each oxide of the molybdenum and the zinc, and simultaneously liquefying or gasifying each of the oxides, and (3) a step for reacting the oxides of the molybdenum and the zinc obtained by being oxidized, and liquefied or gasified, and cooling the reaction product to form the complex oxide. The resin composition contains an organic resin and the flame retardant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a flame retardant which is a composite oxide of molybdenum and zinc, and a method for producing the same, and an antimony compound such as antimony trioxide and a halogenated epoxy resin such as a brominated epoxy resin substantially using the flame retardant. It is related with the resin composition which gives the hardened | cured material excellent in a flame retardance, a moldability, and reliability.

  Currently, resin-encapsulated diodes, transistors, ICs, LSIs, and ultra-LSIs are the mainstream semiconductor devices, but epoxy resins are more formable, adhesive, electrical, and mechanical than other thermosetting resins. Since it is excellent in moisture resistance and the like, it is common to seal a semiconductor device with an epoxy resin composition. Semiconductor devices are used everywhere in our living environment, such as home appliances and computers. Therefore, in preparation for an emergency fire, the semiconductor encapsulant is required to have flame retardancy. In the epoxy resin composition, a halogenated epoxy resin and antimony trioxide are generally blended in order to increase the flame retardancy. The combination of the halogenated epoxy resin and antimony trioxide has a large radical trap and air blocking effect in the gas phase, and as a result, a high flame retardant effect can be obtained.

  However, halogenated epoxy resins have the problem of generating toxic gases when burned, and antimony trioxide is also powder toxic. Considering the effects on the human body and the environment, these flame retardants are contained in the resin composition. It is preferable that it is not contained at all.

In addition, a semiconductor device encapsulated with a resin composition containing the halogenated epoxy resin and antimony trioxide has a problem that it is inferior in reliability such as heat resistance and moisture resistance. The reason why this reliability failure occurs is that an intermetallic compound is generated at the joint between the Al electrode of the semiconductor device and the gold wire, and thus the resistance value increases, and further, the wire is disconnected. It is known that the presence of Br ⁻ or Sb ⁺ contained in the resin composition promotes the formation of this intermetallic compound.

In response to such demands, hydroxides such as Al (OH) ₃ and Mg (OH) ₂ , phosphorus flame retardants and the like have been studied as an alternative to halogenated epoxy resins or antimony trioxide. Yes. However, no matter which compound is used, there are problems such as insufficient fluidity and curability at the time of molding and poor moisture resistance. The current situation is that it has not yet been realized.

  Therefore, recently, it has been proposed to solve the above problem by using a molybdenum-based flame retardant. For example, in JP-A-11-302501, JP-A-11-310688, and JP-A-11-21432 (Patent Documents 1 to 3), silica containing zinc molybdate supported on an epoxy resin is added. , Flame retardancy is manifested. As a method for producing these zinc molybdates, a method in which zinc molybdate is precipitated by an acid-base reaction on an inorganic filler serving as a core based on a molybdenum oxide slurry is generally used. However, since this method is a wet method, drying, agglomeration crushing, firing and production steps are complicated after production, and the cost is increased. In addition, since the film of the zinc molybdate produced is peeled off or chipped because of the crushing and firing process, not all are spherical, and when this is added to the epoxy resin as a semiconductor sealing material, It can also cause a decline in sex.

JP-A-11-302501 JP-A-11-310688 Japanese Patent Laid-Open No. 11-21432

  The present invention has been made in view of the above circumstances, and is a composite oxide fine particle composed of molybdenum and zinc obtained by oxidizing metal powder, which is completely different from the conventional wet method, and is simple and productive. The flame retardant having high and stable performance, its production method, and using this flame retardant, it does not contain antimony compounds such as halogenated epoxy resin and antimony trioxide, and is excellent in flame retardancy, moldability and reliability It aims at providing the resin composition which gives hardened | cured material.

As a result of intensive studies to achieve the above object, the present inventors have (1) put raw material powder having a molar ratio of molybdenum and zinc of 10/90 to 90/10 in a reaction chamber together with a carrier gas. And (2) oxidizing the supplied raw material powder in the reaction chamber to form molybdenum and zinc oxides respectively, and simultaneously liquefying or vaporizing the oxides, and (3) oxidizing them. A step of reacting and cooling each of the oxides of molybdenum and zinc that have been liquefied or vaporized to form a composite oxide, and preferably (4) after the cooling step, the composite oxide is heated to 300 to 600 ° C. in can be obtained by a production method comprising the sintering to process an average particle size of 0.1 to 10 [mu] m, specific surface area of 1-20 m ² / g, 10 ratio molybdenum and zinc at a molar ratio 90-90 / 10 complex oxide is excellent in flame retardancy, and a resin composition comprising this complex oxide as a flame retardant is cured with excellent flame retardancy, moldability and reliability. The present invention has been found, and the present invention has been made.

Therefore, this invention provides the flame retardant shown below, its manufacturing method, and the resin composition using the same.
[1] A flame retardant comprising a composite oxide of molybdenum and zinc, having an average particle size of 0.1 to 10 μm, a specific surface area of 1 to ²⁰ m ² / g, and a ratio of molybdenum to zinc of 10 in molar ratio. A flame retardant characterized by being / 90 to 90/10.
[2] (1) supplying a raw material powder having a molar ratio of molybdenum and zinc of 10/90 to 90/10 in a reaction chamber together with a carrier gas;
(2) oxidizing the supplied raw material powder in a reaction chamber to form oxides of molybdenum and zinc, respectively, and simultaneously liquefying or vaporizing the oxides;
(3) reacting the oxides of molybdenum and zinc that have been liquefied or vaporized by reaction, and forming a composite oxide by cooling; and
Preferably, the method for producing a flame retardant according to [1], further comprising (4) a step of firing the composite oxide at 300 to 600 ° C. after the cooling step.
[3] A resin composition comprising an organic resin and the flame retardant according to the above [1].

Unlike the conventional wet production methods, the method for producing zinc molybdate by the metal powder oxidation method of the present invention can be produced easily and inexpensively.
In addition, the resin composition using this zinc molybdate as a flame retardant can give a cured product having excellent flame retardancy, moldability and reliability, and further, an antimony compound such as a halogenated epoxy resin or antimony trioxide. Since it is not contained in the resin composition, there is no adverse effect on the human body and the environment.

  The raw material powder of the flame retardant used in the present invention has a molar ratio of molybdenum to zinc of 10/90 to 90/10. The raw material powder is preferably a mixture of molybdenum powder and zinc powder. In this case, the molar ratio of molybdenum powder and zinc powder is 10/90 to 90/10, particularly 30/70 to 70/30. And mixed well with a mixer or the like to prepare a mixed raw material powder.

  It is desirable that the molybdenum powder and zinc powder as raw materials have a purity of 99% or more in order to increase the purity of the obtained flame retardant. Both are preferably fine powders in order to oxidize and react in a flame. For example, the average particle size of the molybdenum powder is preferably 1 to 10 μm, and particularly preferably 2 to 5 μm, and the average particle size of the zinc powder is preferably 10 to 50 μm, and particularly preferably 20 to 30 μm.

  The mixed raw material powder is made into a composite oxide fine powder of molybdenum and zinc by an oxidation method. In the metal powder oxidation method, first, the mixed raw material powder is supplied into a reaction vessel together with a carrier gas.

The inside of the reaction vessel is preferably an oxidizing atmosphere. Therefore, it is appropriate to use air, oxygen gas or the like as the carrier gas. The supply amount of the carrier gas is preferably ^{3 to} 10 Nm ³ / hour, particularly about 4 to 6 Nm ³ / hour. If the carrier gas is too small, the raw metal powder may not be well dispersed in the carrier gas, and the resulting composite oxide may be coarsened. If the carrier gas is too large, the oxidation efficiency will deteriorate and unreacted raw materials will be produced. There are cases where a large amount of powder is mixed into the resulting composite oxide.

Furthermore, it is preferable to introduce a combustible gas such as propane gas or hydrogen that forms a flame in the reaction vessel together with the carrier gas. The amount of the combustible gas introduced is preferably about 0.5 to ⁵ Nm ³ / hour, particularly about 1 to ³ Nm ³ / hour.

  In the present invention, the amount of the mixed raw material powder supplied into the reaction vessel is preferably about 5 to 20 kg, particularly about 8 to 12 kg per hour, and the volume of such a reaction vessel is about 1 to 2 kL. Preferably there is. Here, the reaction vessel is preferably lined with a heat insulating material such as alumina brick. The reaction vessel preferably has an ignition source, and the ignition source can generate sparks.

  Next, in the reaction vessel, the supplied combustible gas and air or oxygen gas are ignited to form a flame. The flame usually becomes a high temperature of about 800 to 1600 ° C. The mixed raw material powder of molybdenum and zinc is easily oxidized in this flame to become the respective oxides of molybdenum and zinc. At the same time, these oxides are liquefied or vaporized by the combustion heat of the combustible gas and the oxidation heat of the raw material powder. To do. These liquefied or vaporized molybdenum and zinc oxides react in a high temperature reaction vessel to form a composite oxide, which is cooled as it flows with the combustion exhaust gas at the bottom of the reaction vessel to form spherical particles of zinc molybdate.

  The spherical particles referred to herein are preferably particles having an aspect ratio of 1 to 1.5. The aspect ratio is determined by measuring the particle diameter by microscopic observation and measuring the major axis (D) with respect to the minor axis (d). ) Ratio (D / d).

  The formed complex oxide fine powder is collected together with the combustion exhaust gas. In this case, generally, the reaction can be performed by connecting the reaction vessel and the dust collector and driving the dust collector. As the dust collector, an electric dust collector, a bag filter, a collecting drum type fine powder dust collector or the like can be used.

  The collected and separated composite oxide fine powder has flame retardancy as it is, but when the obtained powder is fired at 300 to 600 ° C. for 1 to 5 hours, the flame retardancy is improved and the ionicity is increased. The characteristics can be further improved, such as a reduction in impurities. Regarding this mechanism, a small amount of simple oxides, molybdenum oxide and zinc oxide in the composite oxide react with zinc molybdate by firing, and ionic impurities adhering to the particle surface may be desorbed by heating. Conceivable. Therefore, if the firing temperature is less than 300 ° C., the above effects may be reduced, and if the temperature exceeds 600 ° C., the particles are sintered with each other, and the advantage of a spherical shape cannot be obtained, and the productivity may be reduced. is there. More preferably, it is 500-600 degreeC. Further, the firing time is preferably 1 hour or more from the viewpoint of production efficiency, and even if it exceeds 5 hours, no further improvement in flame retardancy can be expected, and the productivity may be hindered. More preferably, it is 2-3 hours.

  Zinc molybdate, which is a composite oxide of molybdenum and zinc obtained by the above method, has high flame retardancy and can be used as a flame retardant for resin compositions such as vinyl chloride resins and epoxy resins. Moreover, since it is spherical, it is excellent in dispersibility and fluidity when mixing the resin composition.

  Since the flame retardant of the present invention is not a zinc molybdate film formed on the surface of a substrate as in the prior art, but a composite oxide particle of molybdenum and zinc, the coating layer is peeled off during the handling of the particle. Thus, extremely stable characteristics can be exhibited without causing such problems.

  Moreover, since the method for producing a flame retardant according to the present invention is a method for obtaining a composite oxide by an oxidation method using a metal powder, it is extremely simple, has high production efficiency, and can reduce production costs.

In the present invention, the average particle diameter, specific surface area, and composition ratio of the spherical zinc molybdate can be changed by adjusting the oxidation conditions and the raw material mixing amount. For example, spherical zinc molybdate having an average particle size of 0.1 to 10 μm and a specific surface area of 1 to ²⁰ m ² / g can be obtained by changing the raw material supply amount, the amount of carrier gas, and the concentration of combustible gas. it can.
Further, if the amount of zinc in the raw material powder is increased, the average particle size can be reduced, and if the amount of molybdenum is increased, the average particle size can be increased.

  The flame retardant of the present invention has an average particle size of 0.1 to 10 μm, preferably 0.1 to 5 μm. When the average particle size is less than 0.1 μm, the dispersibility in the resin composition is deteriorated, and when the average particle size exceeds 10 μm, the flame retardancy is lowered.

The flame retardant of the present invention has a specific surface area of 1 to ²⁰ m ² / g, preferably 1 to 10 m ² / g. When the specific surface area is less than 1 m ² / g, the flame retardancy decreases, and when the specific surface area exceeds 20 m ² / g, the dispersibility in the resin composition is deteriorated.

  Furthermore, the flame retardant of the present invention has a molar ratio of molybdenum to zinc of 10/90 to 90/10, preferably 30/70 to 70/30. When the amount of molybdenum is less than 10 mol% with respect to the total amount of molybdenum and zinc, the flame retardancy decreases. On the other hand, when the amount of molybdenum exceeds 90 mol% with respect to the total amount of molybdenum and zinc, curability is lowered.

  Furthermore, the zinc molybdate that is the flame retardant of the present invention preferably has few ionic impurities. Specifically, it is desirable that the electric conductivity of the extracted water when extracted with pure water at 80 ° C. for 24 hours is 500 mS / m or less, particularly 100 mS / m or less. This can be improved by firing the zinc molybdate obtained by the metal powder oxidation method described above.

  The resin composition of the present invention does not contain a conventional flame retardant such as an antimony compound such as antimony trioxide or a halogenated epoxy resin such as a brominated epoxy resin, and the zinc molybdate produced by the oxidation method of the present invention is difficult. Used as a flame retardant. Zinc molybdate itself is known to be effective in reducing smoke and char when plastics are burned. However, since it is a very fine particle by itself, there is a problem that it is difficult to disperse in the resin composition. . However, by using the spherical zinc molybdate produced by the metal powder oxidation method of the present invention, the dispersibility in the resin composition is good, the flowability and curability during molding are not impaired, and halogen Even without using a fluorinated resin, sufficient flame retardancy can be obtained, and a resin composition having excellent reliability can be obtained.

  In the resin composition containing the flame retardant of the present invention, the content of zinc molybdate as the flame retardant is 1 to 100 parts by mass, particularly 2 to 50 parts by mass with respect to 100 parts by mass of the organic resin component in the resin composition. Part. If it is less than 1 part by mass, a sufficient flame retardant effect may not be obtained. If it exceeds 100 parts by mass, fluidity and curability during molding may be deteriorated.

  The resin composition of the present invention preferably contains (A) an epoxy resin, (B) a curing agent, (C) the above flame retardant, and (D) an inorganic filler.

  The epoxy resin as the component (A) is not particularly limited. Common examples include novolac type epoxy resins, cresol novolac type epoxy resins, triphenolalkane type epoxy resins, aralkyl type epoxy resins, biphenyl skeleton-containing aralkyl type epoxy resins, biphenyl type epoxy resins, dicyclopentadiene type epoxy resins, Heterocyclic epoxy resin, naphthalene ring-containing epoxy resin, bisphenol A type epoxy compound, bisphenol F type epoxy compound, stilbene type epoxy resin and the like can be used, and one or more of these can be used in combination. Halogenated epoxy resin is not used.

  (B) The hardening | curing agent of a component is not specifically limited. Common curing agents include phenol novolac resin, naphthalene ring-containing phenol resin, phenol aralkyl type phenol resin, aralkyl type phenol resin, biphenyl skeleton containing aralkyl type phenol resin, biphenyl type phenol resin, dicyclopentadiene type phenol resin, fat Cyclic phenol resin, heterocyclic phenol resin, naphthalene ring-containing phenol resin, phenol resin such as bisphenol A and bisphenol F, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhymix anhydride Acid anhydrides, etc., etc. are mentioned, Among these, 1 type (s) or 2 or more types can be used together.

  Moreover, the compounding quantity ratio of (A) epoxy resin and (B) curing agent is not particularly limited, but (A) phenol contained in (B) curing agent with respect to 1 mol of epoxy group contained in epoxy resin. The molar ratio of the functional hydroxyl group is preferably 0.5 to 1.5, particularly preferably 0.8 to 1.2.

  As an inorganic filler (D) mix | blended in the resin composition of this invention, what is normally mix | blended with an epoxy resin composition can be used. Examples thereof include silicas such as fused silica and crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, glass fiber and the like.

  The average particle diameter and shape of these inorganic fillers are not particularly limited, but spherical fused silica having an average particle diameter of 5 to 40 μm is particularly preferable from the viewpoints of moldability and fluidity.

  The filling amount of the inorganic filler is preferably 400 to 1200 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin and the curing agent. If the amount is less than 400 parts by mass, the expansion coefficient is increased, the stress applied to the semiconductor element is increased, the element characteristics may be deteriorated, and the amount of resin relative to the entire composition is increased. Flammability may not be obtained. On the other hand, when it exceeds 1200 mass parts, the viscosity at the time of shaping | molding will become high, and a moldability may worsen.

  The inorganic filler is preferably blended in advance with a surface treatment with a coupling agent such as a silane coupling agent or a titanate coupling agent in order to increase the bond strength between the resin and the inorganic filler. As such a coupling agent, epoxy silane such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N -Β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, aminosilane such as N-phenyl-γ-aminopropyltrimethoxysilane, and silane such as mercaptosilane such as γ-mercaptosilane It is preferable to use a coupling agent. Here, the blending amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited.

  Moreover, in this invention, in order to accelerate | stimulate the hardening reaction of an epoxy resin and a hardening | curing agent, it is preferable to use a hardening accelerator. The curing accelerator is not particularly limited as long as it accelerates the curing reaction. For example, triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, triphenylphosphine / triphenyl. Phosphorus compounds such as borane, tetraphenylphosphine and tetraphenylborate, tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 1,8-diazabicyclo (5,4,0) undecene-7 Imidazole compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and the like can be used.

  The resin composition of the present invention can further contain various additives as necessary. For example, low stress agents such as thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers, silicones, waxes such as carnauba wax, higher fatty acids, synthetic waxes, colorants such as carbon black, additives such as halogen trapping agents, etc. It can be added and blended within a range that does not impair the object of the present invention. However, antimony compounds such as antimony trioxide are not blended.

  In the resin composition of the present invention, an epoxy resin, a curing agent, a flame retardant, an inorganic filler, and other additives are blended in a predetermined composition ratio, and after sufficiently mixing them with a mixer or the like, a hot roll, a kneader Then, it can be melt-mixed by an extruder or the like, then cooled and solidified, and pulverized to an appropriate size to obtain a molding material.

  The resin composition of the present invention thus obtained can be effectively used for sealing various semiconductor devices. In this case, the most common method for sealing is a low-pressure transfer molding method. In addition, as for the molding temperature of the resin composition of this invention, it is desirable to carry out for 30 to 180 second at 150-180 degreeC, and post-curing at 150-180 degreeC for 2 to 16 hours.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is shown concretely, this invention is not restrict | limited to the following Example.

[Production Example 1]
A molybdenum powder having an average particle diameter of 2 μm and a purity of 99.5% and a zinc powder having an average particle diameter of 30 μm and a purity of 99.0% are blended at a molar ratio of molybdenum: zinc = 50: 50. Thus, 35 kg of mixed raw material powder was prepared. This mixed raw material powder was put into the explosion combustion apparatus shown in FIG. 1 to obtain a composite oxide powder of molybdenum and zinc.

  Here, the apparatus of FIG. 1 includes a reaction vessel 15, a raw material supply unit 10, and a product separation unit 20. The reaction vessel 15 has an inner wall surrounded by heat-resistant bricks 5, and has a discharge port 11 a communicating with the discharge passage 11 on the side wall and a burner 8 connected to the raw material supply unit 10 on the upper surface side. The raw material supply unit 10 is provided with a hopper 1 for storing the raw material powder 2, a pipe 3 serving as a passage for the carrier gas 12 for conveying the raw material powder 2, and a pipe 4 serving as an introduction passage for the combustible gas 13. . The product separation unit 20 is provided with a discharge passage 11 and a powder dust collector 6 and a blower 7 for discharging exhaust gas in the middle of the discharge passage 11.

  Using this manufacturing apparatus, first, a carrier gas (oxygen) 12 is introduced into the reaction vessel 15 through the pipe 3, and a combustible gas (propane gas) 13 is introduced into the reaction vessel 15 through the pipe 4 and ignited by the burner 8. Thus, a flame 9 was formed, and the reaction vessel 15 was sufficiently dried.

The flow rate of the carrier gas 12 was 5 Nm ³ / hour, and the combustible gas 13 was supplied into the reaction vessel 15 at a flow rate of 1.0 Nm ³ / hour. Next, the mixed raw material powder 2 of molybdenum and zinc prepared above was supplied into the reaction vessel 15 through the burner 8 at a supply rate of 10 kg / hour from the hopper 1 with the carrier gas 12 and oxidized in the flame 9.

Next, the blower 7 was operated to discharge the combustion exhaust gas to the outside of the system through the discharge passage 11 and the dust collector 6, thereby collecting and separating the product with a dust collector. In this way, a composite oxide powder of molybdenum and zinc was produced.
The obtained composite oxide powder was baked at 500 ° C. for 3 hours with a hot air circulating dryer to obtain the target zinc molybdate.

When the shape of the obtained complex oxide powder was observed with a transmission electron microscope, it was spherical with an aspect ratio of 1 to 1.2. This transmission electron micrograph is shown in FIG. The average particle size of the composite oxide powder was 0.5 μm. Furthermore, it was 3.8 m < ² > / g when the specific surface area of complex oxide powder was measured. The specific surface area was measured by a BET method using Flowsorb II 2300 manufactured by Shimadzu Corporation.

[Production Example 2]
A composite oxide fine powder of molybdenum and zinc was obtained in the same manner as in Example 1 except that the molar ratio of molybdenum powder and zinc powder was 10:90. The composite oxide powder had an average particle size of 0.2 μm, an aspect ratio of 1 to 1.4, and a specific surface area of 8.4 m ² / g.

[Production Example 3]
A composite oxide fine powder of molybdenum and zinc was obtained in the same manner as in Example 1 except that the molar ratio of molybdenum powder and zinc powder was 40:60. The composite oxide powder had an average particle size of 1.0 μm, an aspect ratio of 1 to 1.2, and a specific surface area of 2.5 m ² / g.

[Production Example 4]
A composite oxide fine powder of molybdenum and zinc was obtained in the same manner as in Example 1 except that the molar ratio of molybdenum powder and zinc powder was 80:20. The composite oxide powder had an average particle size of 4.8 μm, an aspect ratio of 1 to 1.2, and a specific surface area of 1.4 m ² / g.

[Comparative Production Example 1]
Zinc molybdate powder was prepared by the wet method described in the prior art. The preparation method is as follows.

  Molybdenum oxide was dissolved in an aqueous solution in which 0.5 μm of true spherical silica was dispersed, and heated to 80 ° C. to prepare a turbid liquid. Zinc oxide was gradually added to the slurry while stirring, and the mixture was stirred for about 2 hours to precipitate zinc molybdate on silica. The slurry was filtered and washed, and the cake was dried at 110 ° C., then pulverized by a ball mill and fired at 600 ° C. to obtain a zinc molybdate powder. The obtained zinc molybdate powder was spherical, but the coating was peeled off in some places, and many particles were aggregated and sintered.

[Examples 1 to 12, Comparative Examples 1 and 2]
The components shown in Table 1 were uniformly melt-mixed with two hot rolls, cooled and pulverized to obtain an epoxy resin composition for semiconductor encapsulation.

The raw materials used are shown below.
-Epoxy resin (a) o-cresol novolac type epoxy resin:
EOCN1020-55 (Nippon Kayaku, epoxy equivalent 200)
(B) Biphenyl type epoxy resin:
YX-4000HK (Oilized shell, epoxy equivalent 190)
(C) Biphenyl aralkyl type epoxy resin:
NC-3000 (Nippon Kayaku, epoxy equivalent 272)

・ Hardener (d) phenol novolac resin:
DL-92 (Maywa Kasei, phenolic hydroxyl group equivalent 107)
(E) Phenol aralkyl resin:
MEH-7800SS (Maywa Kasei, phenolic hydroxyl group equivalent 175)
(F) Biphenyl aralkyl type phenol resin:
MEH-7851SS (Maywa Kasei Chemical, phenolic hydroxyl group equivalent 203)

Spherical zinc molybdate manufactured by metal powder oxidation method (1) Average particle size 0.5 μm, aspect ratio 1-1.2, specific surface area 3.8 m ² / g, molybdenum / zinc ratio = 50/50 (manufacturing Zinc molybdate from Example 1)
(2) Average particle diameter of 0.2 μm, aspect ratio of 1 to 1.4, specific surface area of 8.4 m ² / g, molybdenum / zinc ratio = 10/90 (zinc molybdate of Production Example 2)
(3) Average particle diameter of 1.0 μm, aspect ratio of 1 to 1.2, specific surface area of 2.5 m ² / g, molybdenum / zinc ratio = 40/60 (zinc molybdate of Production Example 3)
(4) Average particle diameter of 4.8 μm, aspect ratio of 1 to 1.2, specific surface area of 1.4 m ² / g, molybdenum / zinc ratio = 80/20 (Zinc molybdate of Production Example 4)

Inorganic filler: spherical fused silica (manufactured by Tatsumori Co., Ltd., average particle size 20 μm)
・ Curing accelerator: Triphenylphosphine (Hokuko Chemical Co., Ltd.)
-Mold release agent: Carnauba wax (manufactured by Nikko Fine Products Co., Ltd.)
Silane coupling agent: KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

The following properties were measured for these compositions. The results are shown in Table 2.
<Spiral flow value>
Using a mold conforming to the EMMI standard, measurement was performed under the conditions of a temperature of 175 ° C., a molding pressure of 70 kgf / cm ² , and a molding time of 90 seconds.

<Molding hardness>
The hot hardness when a 10 × 4 × 100 mm rod was molded under the conditions of a temperature of 175 ° C., a molding pressure of 70 kgf / cm ² , and a molding time of 90 seconds in accordance with JIS-K6911 was measured with a Barcoll hardness meter.

"Flame retardance"
Based on the UL-94 standard, a 1/16 inch thick plate was molded to examine flame retardancy.

《Moisture resistance》
A 6 × 6 mm silicon chip with aluminum wiring is bonded to a 14 pin-DIP frame (42 alloy), and the aluminum electrode on the chip surface and the lead frame are wire bonded with a 30 μmφ gold wire, The epoxy resin composition was molded under conditions of a temperature of 175 ° C., a molding pressure of 70 kgf / cm ² and a molding time of 90 seconds, and post-cured at 180 ° C. for 4 hours. This package was 130 ° C./85% R.D. H. In this atmosphere, a DC bias voltage of 20 V was applied and left for 500 hours, and then the number of packages in which aluminum corrosion occurred was examined.

  From the results shown in Table 2, the resin composition of the present invention can give a cured product excellent in moldability, flame retardancy and reliability, and an antimony compound such as a halogenated epoxy resin or antimony trioxide is used as the resin composition. Since it is not contained inside, there is no adverse effect on the human body and the environment.

It is a longitudinal cross-sectional view of the manufacturing apparatus used for manufacture of the flame retardant powder of an Example. 2 is a transmission electron micrograph showing the shape of the flame retardant powder of Example 1. FIG.

Explanation of symbols

1 Hopper 2 Mixed raw material powder 3, 4 Pipe 6 Dust collector 9 Flame

Claims (7)

A flame retardant comprising a composite oxide of molybdenum and zinc, having an average particle size of 0.1 to 10 μm, a specific surface area of 1 to ²⁰ m ² / g, and a molar ratio of molybdenum to zinc of 10/90 to A flame retardant characterized by being 90/10.   The flame retardant according to claim 1, wherein the shape is spherical with an aspect ratio of 1 to 1.5. (1) supplying a raw material powder having a molar ratio of molybdenum and zinc of 10/90 to 90/10 together with a carrier gas into the reaction chamber;
(2) oxidizing the supplied raw material powder in a reaction chamber to form oxides of molybdenum and zinc, respectively, and simultaneously liquefying or vaporizing the oxides;
(3) The step of reacting the oxidized and liquefied or vaporized molybdenum and zinc oxide to form a composite oxide by cooling, comprising the step of: Production method.   Furthermore, (4) The manufacturing method of Claim 3 which has the process of baking the said complex oxide at 300-600 degreeC after a cooling process.   A resin composition comprising an organic resin and the flame retardant according to claim 1.   A resin composition comprising (A) an epoxy resin, (B) a curing agent, (C) the flame retardant according to claim 1, and (D) an inorganic filler.   7. The resin composition according to claim 5, wherein the content of the flame retardant is 1 to 100 parts by mass with respect to 100 parts by mass of the total amount of organic resin components in the resin composition.