JP2011084430A - Highly heat resistant aluminum hydroxide particle, preparation method therefor, resin composition containing the same and printed circuit board using the resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preparation method for a highly heat resistant aluminum hydroxide particle having heat resistance and flame retardancy suitable to be used for a substrate for a printed circuit board and the like which has characteristics adaptable to lead free soldering. <P>SOLUTION: In the highly heat resistance aluminum hydroxide particle, at least gibbsite type aluminum and boehmite type aluminum hydroxide are present in one aluminum hydroxide particle. The specific surface area by the BET method is 2.0-50.0 m<SP>2</SP>/g, while the amount of dehydration is 31.5-34.0 mass% and the temperature of starting heat decomposition is higher than 260°C. The method is for the preparation of the particle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to highly heat-resistant aluminum hydroxide particles suitable for addition to a resin as a flame retardant, a method for producing the same, a resin composition containing the particles, and a printed wiring board using the resin composition.

Conventionally, in general, a multilayer printed wiring board is obtained by superimposing a semi-cured material impregnated with epoxy resin on a glass cloth called a prepreg on a printed circuit board in which an inner layer circuit is formed on one side or both sides and heating it with a copper foil. After stacking and integrating by pressing, drill holes called through-holes for interlayer connection are drilled, and electroless plating is performed on the inner wall of the through-hole and the copper foil surface. After the thickness is made small, unnecessary copper is removed to manufacture.
In such a printed wiring board substrate, a resin composition using a halogen-based flame retardant has been used in order to ensure flame retardancy. However, in recent years, with increasing interest in environmental problems, resin compositions filled with metal hydroxides such as aluminum hydroxide and magnesium hydroxide that do not generate harmful substances such as dioxins as flame retardant fillers are increasing. In particular, aluminum hydroxide is preferably used as a flame retardant filler because it has a large amount of dehydration and a large flame retardant effect, and is excellent in chemical resistance such as acid resistance and alkali resistance.

As this aluminum hydroxide, gibbsite type aluminum hydroxide represented by Al (OH) ₃ or Al ₂ O ₃ .3H ₂ O is generally used, and a dehydration reaction with endotherm is performed at a temperature of 200 ° C. or higher. Raised to χ-alumina. And the temperature rise of a resin composition is suppressed by this dehydration reaction, and combustion is suppressed by diluting combustible gas with the generated water vapor.
Moreover, since the electronic component is mounted on the printed wiring board base material by solder, heat resistance equal to or higher than the solder melting temperature is required. Conventionally, Sn—Pb solder has been used as the solder, but due to the toxicity of lead, conversion to lead-free solders such as Sn—Cu and Sn—Ag—Cu is progressing. The melting point of these lead-free solder materials is around 220 ° C., which is about 40 ° C. higher than the 183 ° C. of conventional Sn—Pb solder. For this reason, when the conventional gibbsite type aluminum hydroxide is used, there arises a problem that the aluminum hydroxide causes a dehydration reaction due to heating at the time of mounting, and the base material is swollen by the generated water vapor. Therefore, in order to solve this problem, highly heat-resistant aluminum hydroxide having various thermal decomposition temperatures has been proposed.

For example, in Patent Document 1, by using aluminum hydroxide particles represented by Al ₂ O ₃ .nH ₂ O (n is 1.8 to 2.7), the temperature is about 250 to 260 ° C. It is described that even if heated, a dehydration reaction does not occur and flame retardancy can be imparted to the resin composition.
The aluminum hydroxide particles represented by this Al ₂ O ₃ .nH ₂ O (n is 1.8 to 2.7) are partially bonded with gibbsite-type aluminum hydroxide having 3 water bonds. Transition to boehmite-type aluminum hydroxide having a water number of 1 (hereinafter sometimes simply referred to as “boehmite”). As a result, aluminum hydroxide particles having a bound water number in the range of 1.8 to 2.7 are obtained. It can be obtained.
As the method for producing the aluminum hydroxide particles, a stationary heating method and a fluid heating method can be used. In the stationary heating method, the powder temperature is controlled at 220 to 280 ° C. in the atmosphere, and 1 to In the fluid heating method, it is described that the treatment is performed in a residence time of 15 to 90 minutes while controlling the powder temperature to 220 to 280 ° C. in the fluid heating method.

Further, Patent Document 2 is made of aluminum hydroxide that is less foamed due to dehydration at the environmental temperature used for synthetic resin molding and synthetic resin, does not reduce the yield of synthetic resin products, and has excellent flame retardancy. Flame retardant fillers are described. As a method for producing this flame retardant filler, it is described that gibbsite type aluminum hydroxide and water are mixed and hydrothermally treated at about 160 to 170 ° C. to form boehmite.
Furthermore, in Patent Document 3, the dehydration reaction is high, the foaming due to dehydration is small at the environmental temperature where the synthetic resin is molded and the synthetic resin is used, the yield of the synthetic resin product is not lowered, and a sufficient dehydration amount is maintained. A heat-resistant aluminum hydroxide having excellent flame retardancy is described. As a method for producing this heat-resistant aluminum hydroxide, aluminum hydroxide and a reaction retarder that delays boehmite formation are mixed, and at 170 to 300 ° C., using a pressure vessel such as an autoclave, hydrothermal treatment or a steam atmosphere It is described that pressurization and heating are performed below.

Japanese Patent Laid-Open No. 2002-219918 Japanese Patent No. 4104428 International Publication No. 2004/080897

In Patent Document 1, gibbsite-type aluminum hydroxide particles are heat-treated in the atmosphere to be partially changed into boehmite. Usually, boehmite is hardly precipitated by heat-treatment alone. When the water content when aluminum is expressed as Al ₂ O ₃ .3H ₂ O is reduced from 3 to 1.8 to 2.7, the amount of water that can be released is reduced. It was found that the flame retardance of the printed wiring board substrate was reduced.
Also, in Patent Document 2, gibbsite-type aluminum hydroxide is hydrothermally treated at about 160 to 170 ° C., and part thereof is changed to boehmite. However, since the temperature to change to boehmite is low, unreacted gibbsite-type aluminum is used. Aluminum hydroxide is given only a heat history of about 160 to 170 ° C., and the thermal decomposition start temperature of the aluminum hydroxide particles is low, which is sufficiently high for a printed wiring board substrate using the aluminum hydroxide particles. There is a problem that heat resistance cannot be achieved.

  Furthermore, in Patent Document 3, a reaction retarder that delays boehmite formation is mixed with aluminum hydroxide particles. When this is hydrothermally treated, heat treatment at 170 to 300 ° C. is possible, resulting in high heat resistance. However, when the aluminum hydroxide particles are mixed with a resin, the added reaction retarder may cause deterioration in characteristics such as heat resistance of the resulting synthetic resin composition, and the printed wiring board. There is a possibility that the heat resistance sufficient for a substrate for use cannot be increased.

Therefore, the present invention has been made to solve the above-described problems, and has a wide degree of freedom in selection of a manufacturing apparatus, a manufacturing method, etc., and in particular, a printed wiring board substrate that can handle lead-free solder, etc. It is an object of the present invention to provide highly heat-resistant aluminum hydroxide particles having an appropriate amount of dehydration and a thermal decomposition start temperature that can be suitably used.
Another object of the present invention is to improve the heat resistance and flame retardancy of a printed wiring board substrate or the like using such high heat resistant aluminum hydroxide particles.

  As a result of earnest research to solve the above-mentioned problems, the present invention has revealed that the specific surface area, dehydration amount and heat of aluminum hydroxide particles in which at least gibbsite-type aluminum hydroxide and boehmite-type aluminum hydroxide are present in one particle. The inventors have found that aluminum hydroxide particles having an appropriately adjusted decomposition start temperature are suitable for the above purpose, and have completed the present invention.

That is, the present invention
(1) Aluminum hydroxide particles in which at least gibbsite-type aluminum hydroxide and boehmite-type aluminum hydroxide are present in one particle, and the specific surface area according to the BET method is 2.0 to 50.0 m ² / g. High-heat-resistant aluminum hydroxide particles having a dehydration amount of 31.5 to 34.0% by mass and a thermal decomposition starting temperature higher than 260 ° C.,
(2) High heat-resistant aluminum hydroxide particles according to (1), wherein the content of boehmite type aluminum hydroxide is 5 to 15% by mass,
(3) The high heat-resistant aluminum hydroxide particles according to (1) or (2), wherein χ-alumina is further present,
(4) The high heat-resistant aluminum hydroxide particles according to any one of (1) to (3), wherein the high-heat-resistant aluminum hydroxide particles have an average particle size of 0.5 to 5 μm,
(5) High heat-resistant aluminum hydroxide particles according to any one of (1) to (4), wherein the content of sodium oxide in the high heat-resistant aluminum hydroxide particles is 0.3% by mass or less,
(6) Gibbsite-type aluminum hydroxide particles are heat-treated at 200 to 270 ° C. to change at least the surface of the gibbsite-type aluminum hydroxide particles to χ-alumina, and then hydrothermally heated at 150 to 190 ° C. a method for producing highly heat-resistant aluminum hydroxide particles in which at least boehmite type aluminum hydroxide is present on the surface of aluminum hydroxide particles by changing at least part of χ-alumina to boehmite type aluminum hydroxide,
(7) A resin composition comprising the high heat-resistant aluminum hydroxide particles according to any one of (1) to (5) above,
(8) A prepreg obtained by impregnating and drying the resin composition according to (7) above on a base material,
(9) A laminate having a conductor layer on at least one surface of a cured product of the prepreg according to (8),
(10) A printed wiring board in which a circuit is provided on the conductor layer of the laminated board according to (9),
Is to provide.

According to the present invention, the degree of freedom of selection of a manufacturing apparatus, a manufacturing method, etc. is wide, and in particular, an appropriate amount of dehydration and heat that can be suitably used for a printed wiring board substrate that can handle lead-free solder. High heat-resistant aluminum hydroxide particles having a decomposition start temperature are obtained.
Moreover, if such high heat-resistant aluminum hydroxide particles are used, the heat resistance and flame retardancy of the substrate for printed wiring boards and the like can be improved.

It is a schematic diagram which shows the scheme which (chi) -alumina and boehmite type aluminum hydroxide produce | generate on the surface of a gibbsite type aluminum hydroxide particle. It is a scanning electron micrograph of the surface of aluminum hydroxide in the example of the present invention. It is a scanning electron micrograph of the surface of aluminum hydroxide in the comparative example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail.
In general, thermal decomposition of inorganic substances is considered to start from a surface having a low activation energy, a crystal transition at a grain boundary, or other defective portions. Therefore, in order to improve the heat resistance, it is effective to thermally decompose a surface with low activation energy in advance to change it to a thermally stable material. For example, in gibbsite type aluminum hydroxide particles, χ-alumina, which is a dehydrated product of aluminum hydroxide, is a more thermally stable material than gibbsite type aluminum hydroxide. Therefore, we considered increasing the thermal decomposition starting temperature by changing the surface with low activation energy to a stable dehydrated product. This is because if the thermal decomposition start temperature increases, the heat resistance of the printed wiring board base material increases.

The χ-alumina is also called activated alumina, and is a porous material having a large specific surface area and a high hygroscopic property. For this reason, if the rate of change to χ-alumina due to thermal decomposition of gibbsite-type aluminum hydroxide is high, the amount of moisture retained on the surface will increase due to adsorption when filled as a filler for printed wiring board substrates. A large amount of water vapor is generated up to about 260 ° C. which is the reflow temperature, and heat resistance may be lowered.
Therefore, unlike aluminum hydroxide particles in which gibbsite-type aluminum hydroxide particles are partially heat-treated to change the gibbsite-type aluminum hydroxide directly into boehmite, at least χ-alumina is formed on the surface of the aluminum hydroxide particles. By presenting and appropriately adjusting the rate of change to χ-alumina, highly heat-resistant aluminum hydroxide particles having an appropriate amount of dehydration and a thermal decomposition start temperature can be obtained. It has been found that a printed wiring board substrate containing, etc. has excellent heat resistance and flame retardancy.
However, it is further understood that the presence of χ-alumina on the surface of the aluminum hydroxide particles may not be sufficient in flame retardancy, and χ-alumina is partially changed to boehmite that has no hygroscopicity and high heat resistance temperature. As a result, it was found that a substrate for a printed wiring board having further improved flame retardancy can be obtained.

That is, in one particle, at least gibbsite-type aluminum hydroxide and boehmite-type aluminum hydroxide are present, and the specific surface area according to the BET method is 2.0 to 50.0 m ² / g, High heat-resistant aluminum hydroxide particles having a dehydration amount of 31.5 to 34.0% by mass and a thermal decomposition starting temperature higher than 260 ° C. become aluminum hydroxide particles having excellent heat resistance and flame retardancy. It turned out that the base material for printed wiring boards containing a heat resistant aluminum hydroxide particle becomes the thing excellent in heat resistance and a flame retardance.

The high heat-resistant aluminum hydroxide particles of the present invention, the specific surface area by the BET method, a 2.0~50.0m ² / g, preferably 2.2~30.0m ² / g, 2.5~ 10.0 m ² / g is more preferable. The dehydration amount is 31.5 to 34.0% by mass, preferably 31.7 to 33.5% by mass, and more preferably 32.0 to 33.0% by mass. If the specific surface area and the amount of dehydration are within this range, boehmite will be present in an appropriate proportion at least on the surface, and it is possible to prevent the heat resistance and flame retardancy of the substrate for printed wiring boards and the like from being lowered. Because it can.

Furthermore, the thermal decomposition starting temperature is higher than 260 ° C., preferably 262 ° C. or higher, and more preferably 264 ° C. or higher. This is because this thermal decomposition start temperature results in aluminum hydroxide particles having excellent heat resistance, and the heat resistance of a printed wiring board substrate or the like is not lowered. The upper limit of the thermal decomposition start temperature is not particularly limited, but is preferably 280 ° C. or lower, for example. When the thermal decomposition start temperature exceeds 280 ° C., the hygroscopicity is increased and the flame retardant effect is reduced.
Here, the thermal decomposition start temperature in the present invention is measured from room temperature to 800 ° C. at a temperature rising rate of 10 ° C./min and an air flow rate of 50 ml / min using a differential thermal-gravimetric analyzer, and the mass is based on 110 ° C. This is the temperature at which the reduction rate reaches 0.5% by mass.

  The average particle size of the high heat resistant aluminum hydroxide particles of the present invention is preferably 0.5 to 5 μm, more preferably 1.0 to 4.5 μm, and particularly preferably 2.0 to 4.0 μm. Within this range, it becomes easy to uniformly mix and disperse the aluminum hydroxide particles in the resin composition without agglomeration, and the viscosity when preparing the varnish by adding aluminum hydroxide to the resin material is moderate. This is because the glass substrate can be easily impregnated and molded when the prepreg is pressed without settling. Moreover, if it is this range, it is because it can be set as a thin board | substrate with high insulation reliability also in thickness reduction of the recent printed circuit board.

In general, the thermal decomposition start temperature of aluminum hydroxide particles is affected by the content of impurities contained therein. For example, it is known that the lower the Na ₂ O content, the higher the thermal decomposition start temperature. . Therefore, the Na ₂ O content of the high heat resistant aluminum hydroxide particles of the present invention is preferably 0.3% by mass or less, more preferably 0.1% by mass or less.

Next, the raw material for the high heat resistant aluminum hydroxide particles of the present invention will be described.
The aluminum hydroxide particles as a raw material used in the present invention are gibbsite type aluminum hydroxide particles that are mass-produced industrially. The chemical formula is represented by Al (OH) ₃ or Al ₂ O ₃ .3H ₂ O, and contains 34.64% by mass of water as a theoretical value.
The aluminum hydroxide particles are generally precipitated by adding aluminum hydroxide seed crystals to a hot sodium aluminate solution and then lowering the liquid temperature to form a supersaturated solution. Manufactured. For this reason, a certain amount of sodium is usually contained as an impurity.

Therefore, in order to make the content of Na ₂ O of the high heat-resistant aluminum hydroxide particles of the present invention the above-described preferable content, the content of Na ₂ O of the aluminum hydroxide particles as a raw material is 0.3% by mass. The following is preferable, 0.1% by mass or less is more preferable, and 0.05% by mass or less is particularly preferable. Such aluminum hydroxide particles having a low Na ₂ O content can be produced, for example, by a known method as described in JP-A No. 2004-182555.
The content of Na ₂ O adhering to the surface of aluminum hydroxide is preferably 0.01% by mass or less, more preferably 0.005% by mass or less, and particularly preferably 0.003% by mass or less. This is because if the content of Na ₂ O is about this level, the thermal decomposition starting temperature is lowered and the heat resistance is not lowered.

  Moreover, in order to make the particle diameter of the high heat-resistant aluminum hydroxide particles of the present invention the above preferable particle diameter, the average particle diameter of the aluminum hydroxide particles as a raw material is 0.3 to 5 μm, and further 1 to 4. It is better to keep it 5 μm. Within this range, even if χ-alumina is formed on the surface of aluminum hydroxide and the specific surface area is increased, the preferred particle size range of the high heat-resistant aluminum hydroxide particles of the present invention can be set. Because it can.

Next, the manufacturing method of the high heat resistant aluminum hydroxide particle | grains of this invention is demonstrated based on FIG.
FIG. 1 is a schematic diagram showing a scheme in which χ-alumina and boehmite are generated on the surface of gibbsite-type aluminum hydroxide particles as a raw material.
First, the gibbsite-type aluminum hydroxide particles, which are raw materials as shown in FIG. By this heat treatment, decomposition and dehydration reaction takes place from the surface of aluminum hydroxide having a low surface activation energy, crystal transition of grain boundaries, and other defective portions. As shown in FIG. Part (surface) changes to χ-alumina. Thereby, the part with low thermal decomposition start temperature is removed previously, and thermal decomposition start temperature can be raised. In FIG. 1B, the surface of the gibbsite-type aluminum hydroxide particles is changed to χ-alumina, and the entire surface of the aluminum hydroxide particles is covered with χ-alumina.
The atmosphere for this heat treatment is not particularly limited, and may be an air atmosphere or a nitrogen atmosphere, but it is practical to carry out in an air atmosphere from the viewpoint of cost and the like.

  Further, the processing apparatus and the processing method are not particularly limited, and a box furnace that is a stationary heating method, a rotary kiln that is a fluid heating method, a disk dryer, or the like can be used, but a rotary kiln or a disk dryer is used. More uniform heat treatment becomes possible. Also, rotary kilns and disk dryers are more practical from the viewpoint of mass productivity because they can be operated continuously.

The heat treatment is performed at 200 to 270 ° C., preferably 210 to 260 ° C. If the treatment temperature is within this range, the production rate of χ-alumina is moderate and the amount of dehydration can be easily controlled.
The treatment time is appropriately selected so that the surface of the gibbsite-type aluminum hydroxide particles changes to χ-alumina and the χ-alumina covers the entire surface, for example, 5 minutes to 10 hours, preferably 30 minutes to 7 hours.

Next, hydrothermal treatment is performed on the aluminum hydroxide particles in which χ-alumina is formed on the surface of the aluminum hydroxide particles as shown in FIG. The hydrothermal treatment, as shown in (c) of FIG. 1, changes boehmite some χ- alumina represented by AlOOH or _{Al 2 O 3 · H 2 O} . This is because χ-alumina is a porous material and has a large specific surface area, so it has a large water absorption. Therefore, a part of this χ-alumina is changed to boehmite that does not have hygroscopicity to increase heat resistance. It is. In this regard, even if a part of χ-alumina is changed to boehmite, the heat decomposition temperature of boehmite is 100 ° C. or higher as compared with gibbsite type aluminum hydroxide, so that sufficient heat resistance can be secured. .
Further, χ-alumina that has not changed to boehmite by hydrothermal treatment may exist as χ-alumina, but most of them are considered to be transformed into gibbsite. The gibbsite produced by this transformation once passed through χ-alumina, so it was easy to pyrolyze (the bond strength was relatively weak), the water disappeared, the pyrolysis temperature was high, and the flame retardancy was also retained. Will be able to.
FIG. 1C shows a state in which a part of χ-alumina is changed to boehmite and boehmite type aluminum hydroxide is deposited on the surface of gibbsite.

The boehmite content is preferably in the range of 5 to 15% by mass, more preferably in the range of 6 to 14% by mass, especially 7 to 13% by mass in the total mass of the high heat-resistant aluminum hydroxide particles of the present invention. This is because, within this range, the thermal decomposition starting temperature can be increased without reducing the flame retardancy of the entire high heat resistant aluminum hydroxide particle.
Gibbsite type aluminum hydroxide particles generally contain water having a dehydration amount of 34.4% by mass at 800 ° C. measured by thermal analysis. Boehmite generally contains water having a dehydration amount of 16.6% by mass at 800 ° C. measured by thermal analysis.
Therefore, since most of χ-alumina changes to boehmite or gibbsite by hydrothermal treatment, the boehmite content can be determined from the amount of boehmite dehydrated and the amount of gibbsite dehydrated. It calculated using the following formula (1) from the dehydration amount of 34.4% by mass of aluminum oxide particles at 800 ° C. and the actual dehydration amount of boehmite produced by hydrothermal treatment of aluminum hydroxide, 16.6% by mass.

Boehmite content (% by mass)
= [(34.4-Dehydrated amount of sample (% by mass)) / (34.4-16.6)] x 100
... (1)

Hydrothermal treatment is performed in a pressure-resistant vessel such as an autoclave in which aluminum hydroxide particles subjected to heat treatment are dispersed in water. The treatment temperature is preferably 150 to 190 ° C, more preferably 160 to 180 ° C. If the temperature is within this range, the rate of change from χ-alumina to boehmite is a rate that can withstand practical use, and the rate at which gibbsite-type aluminum hydroxide is converted to boehmite can be suppressed.
The hydrothermal treatment time is preferably 10 minutes to 5 hours, more preferably 30 minutes to 2 hours. This is because the time can be changed from χ-alumina to an appropriate amount of boehmite.
Further, as described above, it is considered that χ-alumina that has not been changed to boehmite has been transformed into gibbsite.
Thereby, the part with low thermal decomposition start temperature is removed beforehand, and it becomes the high heat resistant aluminum hydroxide particle which has the specific surface area, the dehydration amount, and the thermal decomposition start temperature adjusted moderately.
Then, the hydrothermally treated aluminum hydroxide particles are subjected to filtration or centrifugation to remove water and impurities, if necessary, and dried to produce the high heat-resistant aluminum hydroxide particles of the present invention.

Next, the resin composition containing the high heat resistant aluminum hydroxide particles of the present invention will be described.
By adding the high heat-resistant aluminum hydroxide particles of the present invention to a resin, a resin composition containing the high heat-resistant aluminum hydroxide particles of the present invention having high heat resistance can be obtained.
30-150 mass parts is preferable with respect to 100 mass parts of resin materials, and, as for the compounding quantity of high heat resistant aluminum hydroxide, 50-120 mass parts is more preferable. This is because, within this range, sufficient flame retardancy can be obtained, the viscosity of the varnish at the time of blending does not increase, and the moldability of the laminated sheet becomes easy.

The resin used in the present invention is not particularly limited, and for example, epoxy resin, polyimide resin, bismaleimide-triazine resin, phenol resin, melamine resin, modified products of these resins, and the like are used. Two or more kinds of these resins may be used in combination, and various curing agents, curing accelerators and the like may be used as necessary, and these may be blended as a solvent or a solution.
In consideration of the balance between characteristics such as heat resistance and moisture resistance and cost, it is preferable to use an epoxy resin. The epoxy resin is preferably a compound that does not contain halogen and has two or more epoxy groups in the molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, Aliphatic chain epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, phenol biphenylene novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, dicyclopentadiene type epoxy Examples thereof include resins, glycidyl ether compounds of polyfunctional phenols, glycidyl ether compounds of bifunctional alcohols, and alkyl-substituted products and hydrogenated products thereof. These epoxy resins may be used alone or in combination of two or more. Moreover, in order to improve Tg and heat resistance of the resin composition after curing, it is preferable to use an epoxy resin having three or more epoxy groups in the molecule. Examples of such resins include phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, bisphenol F novolak type epoxy resins, and the like.

Examples of the polyimide resin include maleic acid N, N-ethylene-bis-imide, maleic acid N, N-hexamethylene-bis-imide, maleic acid N, N-metaphenylene-bis-imide, maleic acid N, N -Paraphenylene-bis-imide, maleic acid N, N-4,4-diphenylmethane-bis-imide, maleic acid N, N-4,4-diphenyl ether-bis-imide, maleic acid N, N-4,4- Diphenylsulfone-bis-imide, maleic acid N, N-4,4-dicyclohexylmethane-bis-imide, maleic acid N, N-α, α-4,4-dimethylenecyclohexane-bis-imide, maleic acid N, N-4,4-metaxylylene-bis-imide and maleic acid N, N-4,4-diphenylcyclohexane-bis-imide are used. be able to.
As the phenol resin, for example, a resole resin, a phenol novolac resin, an alkylphenol resin, a melamine phenol resin, a benzoguanamine phenol resin, or a phenol-modified polybutadiene can be used.
As the melamine resin, for example, melamine-aldehyde resin, melamine-urea resin, melamine-thiourea resin, melamine-alkyd resin, n-butanol modified melamine resin, i-butanol modified melamine resin and the like can be used.

  As the curing agent, various conventionally known ones can be used. For example, amine compounds, phenolic compounds, acid anhydride compounds, and the like can be used as curing agents when used as an epoxy resin as a resin material. Specific examples of amine compounds include aromatic amines such as diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 1,5-diaminonaphthalene, and m-xylylenediamine. , Ethylenediamine, diethylenediamine, isophoronediamine, bis (4-amino-3-methyldicyclohexyl) methane, aliphatic amines such as polyetherdiamine, dicyandiamide, guanidines such as 1- (o-tolyl) biguanide, and the like. . Specific examples of the phenol compound include bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, tetramethyl bisphenol A, dimethyl bisphenol A, tetramethyl bisphenol F, dimethyl bisphenol F, tetramethyl bisphenol S, and dimethyl. Bisphenol S, tetramethyl-4,4′-biphenol, dimethyl-4,4′-biphenylphenol, 1- (4-hydroxyphenyl) -2- [4- (1,1-bis (4-hydroxyphenyl) ethyl ) Phenyl] propane, 2,2′-methylene-bis (4-methyl-6-tertbutylphenol), 4,4′-butylidene-bis (3-methyl-6-tert-butylphenol), trishydroxyphenylmethane, resorcinol ,Yes Rhoquinone, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, phenolized polybutadiene, phenol, cresols, ethylphenols, butylphenols, octylphenol , Phenolic novolak resins containing various phenols such as bisphenol A, bisphenol F, bisphenol S, naphthols, xylylene skeleton-containing phenol novolac resins, dicyclopentadiene skeleton-containing phenol novolac resins, biphenyl skeleton-containing phenol novolac resins, fluorene skeleton-containing Various novolak resins such as phenol novolac resins are listed. Specific examples of the acid anhydride compound include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol trimellitic anhydride, biphenyltetracarboxylic anhydride, etc. Aromatic carboxylic acid anhydride, azelaic acid, sebacic acid, dodecanedioic acid and other aliphatic carboxylic acid anhydrides, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, nadic acid anhydride, het acid anhydride, Examples thereof include alicyclic carboxylic acid anhydrides such as highmic acid anhydrides. Two or more of these curing agents can be used in combination.

  In the present invention, a curing accelerator may be used, and the type and blending amount are not particularly limited. For example, as an accelerator for use in an epoxy resin, imidazole compounds, organophosphorus compounds, secondary amines, tertiary amines, quaternary ammonium salts, and the like can be used. May be. Examples of imidazole compounds include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-hepta. Decylimidazole, 4,5-diphenylimidazole, 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2-heptadecylimidazoline, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4- Examples include methylimidazole, 2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline. These imidazole compounds may be masked with a masking agent. Examples of the masking agent include acrylonitrile, phenylene diisocyanate, toluidine isocyanate, naphthalene diisocyanate, methylene bisphenyl isocyanate, and melamine acrylate. Examples of organophosphorus compounds include ethylphosphine, propylphosphine, butylphosphine, phenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tricyclohexylphosphine, triphenylphosphine / triphenylborane complex, tetra Examples include phenylphosphonium tetraphenylborate. Secondary amines include morpholine, piperidine, pyrrolidine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dibenzylamine, dicyclohexylamine, N-alkylarylamine, piperazine, diallylamine, thiazolidine, thiomorpholine, and the like. . Tertiary amines include benzyldimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (diaminomethyl) phenol, and the like. Examples of the quaternary ammonium salt include tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrahexylammonium bromide, benzyltrimethylammonium chloride and the like.

  In addition to the high heat resistant aluminum hydroxide, an inorganic filler can be blended in the resin composition of the present invention. The type, shape and particle size of the inorganic filler to be used together are not particularly limited. For example, silica such as fused silica and crystalline silica, calcium carbonate, clay, talc, aluminum oxide, silicon nitride, silicon carbide, boron nitride, Examples thereof include powders such as calcium silicate, potassium titanate, aluminum nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, and titania, or beads and glass fibers obtained by spheroidizing these. Furthermore, examples of the inorganic filler having a flame retardant effect include magnesium hydroxide, zinc borate, and zinc molybdate. Of these, fused silica is preferred from the viewpoint of reducing the thermal expansion coefficient. The shape of the filler is preferably spherical from the viewpoints of high filling and fluidity / penetration into the fine gaps of the resin composition. These inorganic fillers may be used alone or in combination of two or more.

  In order to improve the interfacial adhesion between the resin and the filler and the dispersibility of the inorganic filler, the high heat-resistant aluminum hydroxide and the inorganic filler to be blended in some cases, various coupling agents, silicone polymers, etc. It is preferable to surface-treat the inorganic filler using As the coupling agent, for example, a silane coupling agent, a titanate coupling agent, or the like is used. As the silane coupling agent, carbon-functional silane is used, and 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl (methyl) dimethoxysilane, 2- (2,3-epoxycyclohexyl) ethyltri Epoxy group-containing silane such as methoxysilane; 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyl (methyl) ) Amino group-containing silane such as dimethoxysilane; Cationic silane such as 3- (trimethoxylyl) propyltetramethylammonium chloride; Vinyl group-containing silane such as vinyltriethoxysilane; 3-Methacryloxypropyltrimethoxysilane Acrylic group-containing silane such as Mercapto group-containing silane such as beauty 3-mercaptopropyltrimethoxysilane and the like. On the other hand, examples of titanate coupling agents include alkyl titanates such as titanium propoxide and titanium butoxide. Two or more of these coupling agents and silicone polymers may be used in combination. Moreover, the compounding quantity does not have a restriction | limiting in particular, It is preferable that it is 0.05-5 mass% with respect to an inorganic filler, and 0.1-2.5 mass% is more preferable. If it is this range, the dispersibility of a filler will improve, it can suppress that a void generate | occur | produces in hardened | cured material, heat resistance, mechanical strength will not fall, and a linear expansion coefficient will not become large. Because.

Furthermore, a colorant, an antioxidant, a reducing agent, an ultraviolet shielding agent and the like can be appropriately blended in the resin composition of the present invention as necessary.
Moreover, the resin composition of this invention dilutes with an organic solvent as needed, and varnishes. The solvent used is not particularly limited, and alcohol solvents such as methanol, ethanol, butanol and isopropanol, ether solvents such as tetrahydrofuran, ethylene glycol monomethyl ether, ethyl cellosolve and propylene glycol monomethyl ether, acetone, methyl ethyl ketone and methyl isobutyl. Ketone solvents such as ketone and cyclohexanone, amide solvents such as N-methylpyrrolidone, N, N-dimethylformamide, N-methylformamide and N, N′-diethylacetamide, and fragrances such as benzene, toluene, xylene and trimethylbenzene Aromatic hydrocarbon solvents, ester solvents such as ethyl acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate, and nitriles such as butyronitrile. There are sulfur compound solvents such as tolyl solvents and dimethyl sulfoxide, and these may be used alone or in combination. Moreover, the solid content concentration of the varnish is not particularly limited and can be appropriately changed depending on the resin composition and the like, but is usually preferably in the range of 50% by mass to 80% by mass. If it is this range, it will become a moderate varnish viscosity. Moreover, when using the resin composition of this invention for a prepreg, it is because the resin part of a prepreg also becomes an appropriate quantity and does not impair the external appearance of a prepreg.

The prepreg of the present invention can be produced by impregnating the base material with the resin composition having the high heat-resistant aluminum hydroxide particles of the present invention and drying it in the range of 80 ° C to 200 ° C, for example.
The substrate is not particularly limited as long as it is used when producing a metal foil-clad laminate or a multilayer printed wiring board, but a fiber substrate such as a woven fabric or a nonwoven fabric is usually used. Examples of the fiber substrate include inorganic fibers such as glass, alumina, silica alumina glass, silica glass, tyrano, silicon carbide, silicon nitride, zirconia, aramid, polyether ether ketone, polyether imide, polyether sulfone, and carbon. In addition, there are organic fibers such as cellulose and the like, and mixed papers thereof, and glass fiber woven fabric is particularly preferably used. The type of the glass woven fabric is not particularly specified, and those having a thickness of 20 to 200 μm can be used according to the thickness of the target prepreg or laminate.
In addition, the method for impregnating the varnish with the resin is not particularly limited, and examples thereof include a method of impregnating the substrate with a resin liquid such as a wet method or a dry method, a method of applying a resin composition to the substrate, and the like. .

And at least 1 sheet or more of the prepregs obtained by the above are piled up, and a laminated board is obtained by heat-press molding. The heating temperature is preferably 150 to 250 ° C., more preferably 170 to 200 ° C., and the pressure is preferably 1.0 to 8.0 MPa, more preferably 2.0 to 6.0 MPa. It can be determined appropriately depending on the thickness of the laminate.
Moreover, the base material for printed wiring boards can be manufactured by stacking at least one prepreg, placing a metal foil on one side or both sides thereof, and heating and pressing. As the metal foil, copper foil or aluminum foil is mainly used, but other metal foil may be used. The thickness of the metal foil is usually 3 to 200 μm. Using these printed wiring board base materials, a printed wiring board can be obtained by circuit processing.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
First, the Example and comparative example about the high heat resistant aluminum hydroxide particle | grains of this invention are shown below. The average particle diameter, specific surface area, amount of dehydration, thermal decomposition start temperature and X-ray diffraction pattern of aluminum hydroxide particles were measured by the following methods.
[Average particle size]
The average particle diameter of aluminum hydroxide was measured using Nikkiso Co., Ltd. laser scattering particle size distribution meter MT3000 as a dispersion.

〔Specific surface area〕
The specific surface area of the aluminum hydroxide particles was measured by the BET method with a fully automatic gas adsorption amount measuring device AUTO SORB-1 manufactured by Yuasa Ionics Co., Ltd.
[Dehydration amount, thermal decomposition start temperature]
The amount of dehydration of the aluminum hydroxide particles was measured from room temperature to 800 ° C. at a heating rate of 10 ° C./min and an air flow rate of 50 ml / min using a differential thermal-gravimetric analyzer TG-DTA2000 manufactured by Mac Science Co., Ltd. It calculated from the heating mass reduction | decrease amount in 800 degreeC on the basis of degreeC.
In addition, the thermal decomposition starting temperature was the temperature at which the mass reduction rate became 0.5% by mass based on 110 ° C. in this measurement.
[X-ray diffraction pattern]
The X-ray diffraction pattern of the aluminum hydroxide particles was measured with a Rigaku X-ray diffractometer RAD3 at a tube voltage of 40 kV and a tube current of 20 mA.

Example 1
HP-360 (average particle diameter: 3.2 μm, specific surface area: 1.3 m ² / g, dehydration amount: 34.4 mass%) manufactured by Showa Denko KK was used as the gibbsite-type aluminum hydroxide particles as the raw material.
This gibbsite-type aluminum hydroxide particle was filled to a thickness of 1 cm in a stainless steel container having an inner diameter of 10 cm, and subjected to heat treatment at 230 ° C. for 5 hours in a hot air circulation type box furnace (Fine Oven DH42 manufactured by Yamato Scientific Co., Ltd.). The particles obtained by this heat treatment had a specific surface area of 5.0 m ² / g and a dehydration amount of 32.8% by mass.
Then, when the X-ray diffraction pattern of the obtained particles was measured, the X-ray diffraction pattern of gibbsite type aluminum hydroxide was measured. Furthermore, when observed with a scanning electron microscope, no crystal phase was observed on the surface of the particles, and the surface of the aluminum hydroxide particles was assumed to be changed to amorphous χ-alumina.

Thereafter, 50 g of water was put into a stainless steel pressure vessel having a 100 ml Teflon (registered trademark) inner cylinder, and then 10 g of particles (aluminum hydroxide particles having χ-alumina formed on the surface) subjected to heat treatment were added. Subsequently, the pressure vessel was placed in the hot air circulation type box furnace and subjected to hydrothermal treatment at 160 ° C. for 1 hour. After hydrothermal treatment, the resulting particles were filtered and dried at 150 ° C.
Table 1 shows the average particle diameter, specific surface area, amount of dehydration, thermal decomposition start temperature, and boehmite content calculated from the formula (1) of the aluminum hydroxide particles obtained by hydrothermal treatment. Further, the content of sodium oxide in the particles was 0.1% by mass or less.
Moreover, it was confirmed from the result of the X-ray diffraction pattern measurement that a boehmite crystal phase was generated, and the intensity ratio of the boehmite (020) plane to the gibbsite (002) plane was 1: 9.
Further, from observation with a scanning electron microscope, it was inferred that rhomboid boehmite crystals in which χ-alumina changed mainly were formed in the particles. A photograph of this scanning electron microscope is shown in FIG.
As a result, it was confirmed that the obtained particles were highly heat-resistant aluminum hydroxide particles having both an appropriate amount of dehydration and a thermal decomposition start temperature.

(Example 2)
Heat-resistant aluminum hydroxide particles were produced in the same manner as in Example 1 except that the temperature and time of the heat treatment were changed to 250 ° C. for 2 hours and the temperature and time of the hydrothermal treatment were changed to 180 ° C. for 2 hours. .
The particles obtained by the heat treatment had a specific surface area of 28.5 m ² / g and a dehydration amount of 31.9% by mass. Then, when the X-ray diffraction pattern of the obtained particles was measured, the X-ray diffraction pattern of gibbsite type aluminum hydroxide was measured. As in Example 1, the surface of the aluminum hydroxide particles was assumed to be changed to amorphous χ-alumina.
Table 1 shows the average particle diameter, specific surface area, dehydration amount, thermal decomposition start temperature, and boehmite content calculated from the formula (1) of the particles obtained by the subsequent hydrothermal treatment. The content of sodium oxide in the particles was 0.1% by mass or less. Moreover, it was confirmed from the result of the X-ray diffraction pattern measurement that a boehmite crystal phase was generated, and the intensity ratio of the boehmite (020) plane to the gibbsite (002) plane was 1: 8. As in the case of Example 1, it was presumed that diamond-shaped boehmite crystals in which chi-alumina mainly changed were formed.
As a result, it was confirmed that the obtained particles were highly heat-resistant aluminum hydroxide particles having both an appropriate amount of dehydration and a thermal decomposition start temperature.

(Example 3)
Except for using gibbsite-type aluminum hydroxide particles as a raw material, CL-303 (average particle size 4.1 μm, specific surface area 1.6 m ² / g, dehydration amount 34.4 mass%) manufactured by Sumitomo Chemical Co., Ltd. In the same manner as in Example 1, heat treatment and hydrothermal treatment were performed.
The particles obtained by the heat treatment had a specific surface area of 6.5 m ² / g and a dehydration amount of 32.1% by mass. Then, when the X-ray diffraction pattern of the obtained particles was measured, the X-ray diffraction pattern of gibbsite type aluminum hydroxide was measured. As in Example 1, the surface of the aluminum hydroxide particles was assumed to be changed to amorphous χ-alumina.
Table 1 shows the average particle diameter, specific surface area, dehydration amount, thermal decomposition start temperature, and boehmite content calculated from the formula (1) of the particles obtained by the subsequent hydrothermal treatment. The content of sodium oxide in the particles was 0.1% by mass or less. Moreover, it was confirmed from the result of the X-ray diffraction pattern measurement that a boehmite crystal phase was generated, and the intensity ratio of the boehmite (020) plane to the gibbsite (002) plane was 1: 8.5. As in the case of Example 1, it was presumed that diamond-shaped boehmite crystals in which chi-alumina mainly changed were formed.
As a result, it was confirmed that the obtained particles were highly heat-resistant aluminum hydroxide particles having both an appropriate amount of dehydration and a thermal decomposition start temperature.

(Comparative Example 1)
Aluminum hydroxide particles were produced in the same manner as in Example 1 except that the temperature and time of the heat treatment were changed to 170 ° C. for 5 hours.
The particles obtained by the heat treatment had a specific surface area of 1.4 m ² / g and a dehydration amount of 34.1% by mass.
Table 1 shows the average particle diameter, specific surface area, dehydration amount, thermal decomposition start temperature, and boehmite content calculated from the formula (1) of the particles obtained by the subsequent hydrothermal treatment. The content of sodium oxide in the particles was 0.1% by mass or less. Moreover, it was confirmed from the result of the X-ray diffraction pattern measurement that a boehmite crystal phase was generated, and the intensity ratio of the boehmite (020) plane to the gibbsite (002) plane was 1:30.
As a result, it was confirmed that the obtained particles had an appropriate amount of dehydration, but had a small specific surface area and a low thermal decomposition starting temperature.

(Comparative Example 2)
Aluminum hydroxide particles were produced in the same manner as in Example 2 except that the hydrothermal treatment temperature and time were changed to 100 ° C. for 2 hours.
The specific surface area and the amount of dehydration of the particles obtained by the heat treatment were similar to those in Example 2.
Table 1 shows the average particle diameter, specific surface area, amount of dehydration, and thermal decomposition start temperature of the particles obtained by the subsequent hydrothermal treatment. The content of sodium oxide in the particles was 0.1% by mass or less. Moreover, the production | generation of the boehmite crystal phase was not able to be confirmed from the result of the X-ray diffraction pattern measurement.
As a result, it was confirmed that the obtained particles had a low dehydration amount and a low thermal decomposition starting temperature.

(Comparative Example 3)
Aluminum hydroxide particles were produced in the same manner as in Example 1 except that the hydrothermal treatment temperature and time were changed to 210 ° C. for 2 hours.
The specific surface area and the amount of dehydration of the particles obtained by the heat treatment were similar to those in Example 1.
Table 1 shows the average particle diameter, specific surface area, amount of dehydration, and thermal decomposition start temperature of the particles obtained by the subsequent hydrothermal treatment. The content of sodium oxide in the particles was 0.1% by mass or less. Further, from the result of X-ray diffraction pattern measurement, it was confirmed that only the boehmite crystal phase was present and the gibbsite crystal phase disappeared.
Moreover, it was confirmed from the scanning electron microscope observation that only rhombus boehmite crystals were formed. A photograph of this scanning electron microscope is shown in FIG.
As a result, it was confirmed that the obtained particles had a high thermal decomposition starting temperature but a small amount of dehydration.

(Comparative Example 4)
HP-360 (average particle size: 3.2 μm, specific surface area: 1.3 m ² / g, dehydrated amount: 34.4 mass%) manufactured by Showa Denko KK as gibbsite type aluminum hydroxide particles and Kawai lime as boehmite type aluminum hydroxide particles BMB manufactured by Kogyo Co., Ltd. (average particle size 2.2 μm, specific surface area 2.5 m ² / g, dehydrated amount 16.6% by mass) is mixed at a mass ratio of 90:10 to contain 10% by weight of boehmite. Aluminum oxide particles were produced. Table 1 shows the average particle diameter, specific surface area, dehydration amount, thermal decomposition start temperature, and boehmite content of the mixed particles. The content of sodium oxide in the particles was 0.1% by mass or less. Moreover, it was confirmed from the result of the X-ray diffraction pattern measurement that a boehmite crystal phase was generated, and the intensity ratio of the boehmite (020) plane to the gibbsite (002) plane was 1: 9.
As a result, it was confirmed that the obtained particles had an appropriate amount of dehydration, but had a small specific surface area and a low thermal decomposition starting temperature.

Next, using the high heat-resistant aluminum hydroxide particles of Examples 1 to 3 and the aluminum hydroxide particles of Comparative Examples 1 to 4, a laminated plate in which copper foil is laminated on both sides of the cured prepreg is manufactured. The moisture absorption rate, moisture absorption heat resistance and flame retardancy of the laminate were evaluated.
(Manufacture of laminates)
For each of the high heat-resistant aluminum hydroxide particles of Examples 1 to 3 and 65 parts by mass of the aluminum hydroxide particles of Comparative Examples 1 to 4 as aluminum hydroxide particles, a bisphenol A novolac type epoxy resin (large 65.4 parts by mass of EPICLON N865 manufactured by Nippon Ink Chemical Co., Ltd., epoxy equivalent: 205), 34.6 parts by mass of phenol novolac resin (HF-4, hydroxyl equivalent: 108 manufactured by Meiwa Kasei Co., Ltd.) as a curing agent, As a curing accelerator, 0.2 parts by mass of 2-ethyl-4-methylimidazole (2E4MZ, manufactured by Shikoku Kasei Co., Ltd.), 30 parts by mass of spherical fused silica (SO-25H, manufactured by Admatex Co., Ltd.) having an average particle size of 0.5 μm , Zinc molybdate-carrying talc as a flame retardant aid (Kem manufactured by Sherwin Williams) 5 parts by weight of gard 911C) and 85.8 parts by weight of methyl ethyl ketone were prepared to prepare a varnish having a solid content of 70% by weight.

  These varnishes were impregnated into a glass cloth (# 2116, E-glass) having a thickness of about 0.1 mm and then dried by heating at 160 ° C. for 3 to 10 minutes to obtain a prepreg having a resin content of 48% by weight. Four of these prepregs were stacked, a copper foil having a thickness of 18 μm was stacked on both sides thereof, and pressed at 180 ° C. for 90 minutes under a pressure of 3.0 MPa to prepare a double-sided copper-clad laminate. Using this laminate, the moisture absorption rate, moisture absorption heat resistance and flame retardancy were evaluated.

[Hygroscopic rate]
The produced laminate was cut into 50 mm squares to produce three measurement samples, the copper foil was removed by etching, a moisture absorption treatment was performed with a pressure cooker device at 125 ° C. for 5 hours, and the moisture absorption rate was measured from the change in mass. .
[Hygroscopic heat resistance]
The produced laminate was cut into 50 mm squares to produce three measurement samples, the copper foil was removed by etching, and immersed in a solder at 288 ° C. for 20 seconds, and the occurrence of swelling was observed.

〔Flame retardance〕
The copper foil of the produced laminated board is removed by etching, cut into 10 cm length and 1 cm width, 5 samples are prepared, a vertical combustion test is performed, and the average burning time and maximum burning time of 5 samples are measured. , Evaluated by the burning time according to the UL-94 vertical method. The average combustion time of 5 seconds or less and the maximum combustion time of 10 seconds or less were designated as V-0, and the average combustion time of 10 seconds or less and the maximum combustion time of 30 seconds or less were designated as V-1.
Table 2 shows the results of the moisture absorption rate, moisture absorption heat resistance and flame retardancy. In Table 2, laminates 1 to 3 are laminates using the high heat-resistant aluminum hydroxide particles of Examples 1 to 3, respectively, and laminates 4 to 7 are aluminum hydroxide particles of Comparative Examples 1 to 4 above. It is a laminated board using each.

In the laminated plates 1 to 3 using the high heat resistant aluminum hydroxide particles obtained in Examples 1 to 3, the moisture absorption amount is 0.46 to 0.47% by mass, the number of peeling occurrence samples is zero, and the moisture absorption heat resistance is zero. It was excellent in nature. Further, the average combustion time was 4.3 to 4.8 seconds, the maximum combustion time was 7 to 8 seconds, UL-94 was V-0, and the flame retardancy was excellent.
On the other hand, the laminated plate 4 using the aluminum hydroxide particles of Comparative Example 1 having a heat treatment temperature as low as 170 ° C. has a moisture absorption amount, an average burning time, a maximum burning time, and UL-94 as laminated plates 1 to 3. Although it was about the same, the number of peeled samples was 3, which was inferior in moisture absorption heat resistance.

In addition, the laminated plate 5 using the aluminum hydroxide particles of Comparative Example 2 having a low hydrothermal treatment temperature of 100 ° C. had an average combustion time and UL-94 that were about the same as those of the laminated plates 1 to 3, but the moisture absorption amount was as follows. It was as large as 0.68% by mass, the number of peeled samples was 3, and the moisture absorption heat resistance was poor. Moreover, the maximum combustion time was 9 seconds and inferior to the laminated plates 1-3.
Furthermore, the laminated plate 6 using the aluminum hydroxide particles of Comparative Example 3 having a high hydrothermal treatment temperature of 210 ° C. had the same hygroscopic heat resistance as the laminated plates 1 to 3, but changed from gibbsite to boehmite, Since the amount of dewatering decreased, the average burning time was 8.9 seconds, and the maximum burning time was 15 seconds, which was inferior to the laminates 1 to 3.
Further, the laminated plate 7 using the aluminum hydroxide particles of Comparative Example 4 in which the gibbsite type aluminum hydroxide particles and the boehmite type aluminum hydroxide particles are simply mixed has a moisture absorption amount, an average combustion time, a maximum combustion time, and a UL. Although −94 was about the same as that of the laminated plates 1 to 3, the number of peeled samples was 3 and the moisture absorption heat resistance was poor.

From this result, according to the present invention, it can be confirmed that highly heat-resistant aluminum hydroxide particles having a dehydration amount and a thermal decomposition starting temperature suitable for addition as a flame retardant to a synthetic resin can be provided. did it.
And if this highly heat-resistant aluminum hydroxide particle is used, a laminated board with low hygroscopicity and excellent heat resistance and flame retardancy can be provided.

  The present invention can provide highly heat-resistant aluminum hydroxide particles suitable for addition as a flame retardant, and can improve the heat resistance and flame retardancy of a printed wiring board substrate that can be used for lead-free solder. Printed wiring boards and the like can be provided.

Claims (10)

Aluminum hydroxide particles in which at least gibbsite-type aluminum hydroxide and boehmite-type aluminum hydroxide are present in one particle, the specific surface area by the BET method is 2.0 to 50.0 m ² / g, and the amount of dehydration Is high heat-resistant aluminum hydroxide particles having a thermal decomposition start temperature higher than 260 ° C.   The heat-resistant aluminum hydroxide particles according to claim 1, wherein the content of boehmite type aluminum hydroxide is 5 to 15% by mass.   The high heat-resistant aluminum hydroxide particles according to claim 1 or 2, wherein χ-alumina is further present.   The high heat resistant aluminum hydroxide particles according to any one of claims 1 to 3, wherein the high heat resistant aluminum hydroxide particles have an average particle diameter of 0.5 to 5 µm.   The high heat resistant aluminum hydroxide particles according to any one of claims 1 to 4, wherein the content of sodium oxide in the high heat resistant aluminum hydroxide particles is 0.3% by mass or less.   Gibbsite type aluminum hydroxide particles are heat-treated at 200 to 270 ° C. to change at least the surface of the gibbsite type aluminum hydroxide particles to χ-alumina, and then hydrothermally heated at 150 to 190 ° C. to produce the χ-alumina. A method for producing highly heat-resistant aluminum hydroxide particles in which at least boehmite type aluminum hydroxide is present on the surface of the aluminum hydroxide particles by changing at least a part thereof to boehmite type aluminum hydroxide.   The resin composition containing the high heat resistant aluminum hydroxide particle in any one of Claims 1-5.   A prepreg obtained by impregnating and drying a resin composition according to claim 7 on a substrate.   A laminate having a conductor layer on at least one surface of a cured product of the prepreg according to claim 8.   A printed wiring board comprising a circuit on the conductor layer of the laminated board according to claim 9.

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