TW201827382A - Silicone-based hybrid polymer-coated AlN filler - Google Patents

Abstract

According to the present invention, a surface-coated AlN filler for obtaining a heat-resistant heat dissipation material that is suppressed in deterioration of characteristics such as thermal conductivity due to hydrolysis of the AlN filler surface is obtained, said heat dissipation material being able to be used in a heat dissipation member that requires high thermal conduction characteristics. A silicone-based hybrid polymer-coated AlN filler according to the present invention is mainly composed of aluminum nitride; and the surface of this filler is coated with a silicone-based hybrid polymer. If 5 g of this filler, which has an average particle diameter of 20-40 [mu]m, is added into 50 mL of an ion exchange water, the electrical conductivity of the water after being held at 121 DEG C under saturated water vapor pressure for 50 hours is 350 [mu]S/cm or less.

Description

Siloxane hybrid polymer coated aluminum nitride filler

The present invention relates to a filler whose main component is aluminum nitride obtained by coating a surface with a siloxane-based mixed polymer (hereinafter, this filler is referred to as "AlN filler").

A composite member (hereinafter, referred to as a "radiating member") for the purpose of implementing heat dissipation or heat dissipation by high heat conduction characteristics has been widely used mainly for heavy-electricity-related or electrical products. This heat radiating member is composed of a composite material such as a ceramic or metal filler having high thermal conductivity and a heat-resistant resin capable of imparting elasticity. In recent years, with the increase in density and accumulation of electronic components, the required thermal conductivity has gradually increased. Among them, there are many applications requiring high electrical insulation. That is, both electrical insulation and high thermal conductivity are required. Generally, a substance having a high thermal conductivity has a high electrical conductivity. Therefore, the required characteristics are reversed. For such requirements, ceramics such as alumina and zirconia are used, but their thermal conductivity is not a satisfactory value compared to metals and the like.

As a ceramic having a higher thermal conductivity than an oxide ceramic, a nitride ceramic such as aluminum nitride is used. Aluminum nitride (AlN) has high insulation properties and has a high thermal conductivity of 170 W ･ m ^-1 ･ K ^-1 . Therefore, aluminum nitride (AlN) has been widely used as a high heat conductive insulating plate. Attempts have been made to use such nitride ceramics such as AlN as fillers and blend them with various resins to produce functional materials with high thermal conductivity. AlN fillers can provide high thermal conductivity to resins with low thermal conductivity. Therefore, AlN fillers and resins are combined to form heat-dissipating members, and they have been put to practical use as cooling elements in various fields.

However, it is known that the AlN filler used for such applications easily reacts with moisture in the atmosphere to undergo hydrolysis, and is decomposed into aluminum hydroxide and ammonia (AlN + 3H ₂ O → Al (OH) ₃ + NH ₃ ). When AlN is hydrolyzed to become Al (OH) ₃ , the thermal conductivity is reduced, and high thermal conductivity cannot be imparted to the composite material. In particular, silicone resins and nylon resins used in heat-conducting sheets that emphasize heat resistance have low gas barrier properties that can block water vapor from the atmosphere, and AlN compounded as a filler is easily hydrolyzed. Propensity. Therefore, in a resin having low gas barrier properties, AlN is easily hydrolyzed, and thus the thermal conductivity decreases with time.

In addition, since most general-purpose resins use solid pellets to melt-knead (biaxial kneading-extrusion molding) under atmospheric and high-temperature conditions to perform filler mixing, the mixed filler is exposed to water. The case of steam is not unusual. Therefore, the blended filler, especially the AlN filler, must be surface-treated to stabilize it.

In general, as a water-resistant treatment agent for an AlN filler, various coupling agents such as a silane coupling agent or a phosphoric acid-based treatment agent are known.

Various coupling agents prevent the hydration (hydrolysis) of AlN fillers by making the surface of the AlN fillers have a certain degree of water resistance and making the surface of the AlN fillers have a good affinity with the resin to prevent water from entering the AlN filler / resin interface. Situations have some effect. However, since the adhesion as a coating is weak and the film quality is also hardened, cracks or interfacial peeling are likely to occur on the surface. Therefore, the durability of the stress such as the kneading step of the AlN filler is insufficient, and it is difficult to make stable protection. membrane.

The phosphoric acid-based treatment agent can form a very strong water-resistant layer on the surface of the AlN filler, but it is very difficult to completely remove the phosphoric acid component. The remaining phosphoric acid component causes corrosion problems such as copper wiring depending on the use. Therefore, it is limited to the following. Application: Used in places not in contact with metal.

As the most effective method, there is a method that uses a silicone oil and forms a protective layer on the surface of the AlN filler by high-temperature baking, but has the following problems: the processing is complicated and special and cannot be easily implemented, so the processing cost is high. It becomes high and reduces an important characteristic, that is, thermal conductivity.

In addition, in order to improve the problems of silane coupling agent treatment or baking hardening of silicone oil, various silane-based materials have been studied, but it is still difficult to obtain a heat-radiating material, which can form good and stable adhesion on the surface of the AlN filler. The coating can be stabilized for a long period of time by uniformly dispersing it in an organic polysiloxane resin or epoxy resin (Patent Documents 1 to 3). [Prior Art Literature] (Patent Literature)

Patent Document 1: Japanese Patent Application Publication No. 2013-091680 Patent Document 2: Japanese Patent Application Publication No. 2011-153252 Patent Document 3: Japanese Patent Application Publication No. 2011-153253

[Problems to be Solved by the Invention] As a method for solving the problems of AlN fillers as described above, attempts have been made to cover the surface of AlN fillers with a silicone polymer or the like to suppress hydrolysis of the surface of the AlN fillers. Dimethylsiloxane and alkoxysilane oligomers are used as the main raw material for the preparation of the silica-based mixed prepolymer to protect the surface of the AlN filler, but there are still problems.

A hybrid polymer obtained from the above-mentioned silicone-based hybrid prepolymer has been proposed as a material, which has the organic component, that is, the flexibility, water repellency, and release properties of the silicone resin, and is used for crosslinking. Adhesiveness of alkoxysilane oligomer introduced as an inorganic component, the material has high heat resistance and flexibility even at continuous use temperature of 200 ° C or higher.

However, even if such a silica-based mixed prepolymer is used, it is not easy to perform a surface treatment that does not deteriorate the surface of the filler. As the AlN filler, there are the following particles: particles having a particle diameter of about 1 μm synthesized by a reduction nitridation method or a direct nitridation method, or particles growing from several μm particles to 20 μm particles; or about 1 μm The particles are used as primary particles and dispersed in an organic solvent-based or water-based solvent. Then, additives such as a binder are appropriately added to make it into a slurry state, and granulation is performed by a spray dryer. Particles sintered in a high-temperature nitrogen atmosphere. The obtained AlN filler has a plurality of fine irregularities on the surface. Therefore, a simple surface treatment technique cannot form a thin protective layer on the surface layer, and the film thickness is liable to cause unevenness. As a result, the protective film lacks durability.

In particular, the silica-based hybrid prepolymers that have been developed so far generally use polydimethylsiloxane (PDMS) as a raw material in order to improve heat resistance. The mixed prepolymer has high viscosity, and it is difficult to uniformly treat fine unevenness. As a result, hydrolysis of the surface of the AlN filler cannot be sufficiently suppressed to maintain high thermal conductivity of the AlN filler. In addition, due to the high viscosity, the thickness of the coating film by the surface treatment becomes thicker, so that there is also a problem that the thermal conductivity decreases.

The present invention is to provide a heat-dissipating member capable of solving the conventional problems of the above-mentioned AlN filler and having excellent heat resistance and thermal conductivity. By using the obtained hybrid polymer, a silicone-based hybrid prepolymer having both heat resistance and flexibility is used. A protective layer is formed on the surface of the AlN filler to suppress the hydrolysis of the surface of the AlN filler and prevent the thermal conductivity from decreasing. [Technical means to solve the problem]

The silicon-oxygen mixed polymer-coated AlN filler obtained in accordance with the present invention is a filler mainly composed of aluminum nitride whose surface is coated with a silicon-oxygen mixed polymer, and 50 g of ion-exchanged water is added with an average of 5 g. After the filler having a particle diameter of 20 to 40 μm is maintained at a saturated water vapor pressure of 121 ° C. for 50 hours, the conductivity of water is 350 μS / cm or less.

By performing in this manner, it is possible to obtain a silicon-oxygen mixed polymer-coated AlN filler, which can suppress the hydrolysis of the filler surface without impairing the thermal conductivity of the AlN filler and without impairing the thermal conductivity of the composite resin as a heat-radiating member. .

The silica-based hybrid polymer-coated AlN filler obtained according to the present invention is preferably: for 50 mL of ion-exchanged water, 5 g of the filler having an average particle diameter of 20 to 40 μm is added and maintained at a saturated water vapor pressure of 121 ° C. After 50 hours, the pH of the water was 10 or less.

In the silica-based hybrid polymer-coated AlN filler obtained according to the present invention, it is preferable that the silica-based hybrid polymer is a cured product containing polydimethylene represented by the following general formula (1) The reaction product of a polysiloxane and a tetraalkoxysilane oligomer and / or a hydrolyzate thereof represented by the following general formula (2), the number average molecular weight (Mn) of the polydimethylsiloxane is 500 ~ 3000; m is an integer capable of satisfying the number average molecular weight (Mn) = 500-3000, and mixed with an integer m within a certain range; n represents an integer of 4 to 10, and R represents an alkyl group having 1 to 3 carbon atoms.

By performing in this way, it is possible to produce a heat dissipation member which can prevent deterioration of the filler and has high functionality.

This siloxane system is mixed into a prepolymer and has a silanol group (OH group) or an alkoxy group (OR group) which is reactive at the terminal or side chain. These functional groups easily react with reactive functional groups (Al-OH groups) existing on the surface of the AlN filler in the presence of heat or moisture to form stable inorganic bonds (Al-O-Si-O-). By this bonding, a direct bond can be formed with the AlN surface, and the effect as a protective film can be exhibited. Since the effect is exhibited by using a thin film as an intermediate protective film, a decrease in thermal conductivity does not occur. Since the film has a PDMS skeleton, it is rich in flexibility and can relieve mechanical external stress, so it is unlikely to break or peel. The bond formed between the surfaces of the AlN filler is also thermally stable, and it can be used stably as a heat sink to a high temperature of about 250 ° C.

In this specification, the number average molecular weight (Mn) refers to a molecular weight measured by a gel permeation chromatography method (GPC method), which uses polystyrene as a standard material, Tetrahydrofuran was used as the eluent.

In addition, the silica-based hybrid polymer coated AlN filler of the present invention has a plurality of methyl groups arranged on the polymer molecular skeleton. Due to its high water-repellent effect, the effect of preventing moisture from entering the silica-based hybrid polymer / AlN filler interface Larger. This is also one of the main factors that can inhibit the hydrolysis of AlN fillers.

In the silica-based hybrid polymer-coated AlN filler obtained according to the present invention, the number average molecular weight (Mn) of the polydimethylsiloxane represented by the general formula (1) is more preferably 600 to 2000.

The silica-based hybrid polymer-coated AlN filler obtained according to the present invention preferably has an average particle diameter of 25 to 35 μm.

In the silicon-oxygen mixed polymer-coated AlN filler obtained according to the present invention, the mass ratio of the silicon-oxygen mixed polymer-coated AlN filler and the silicon-oxygen mixed prepolymer is preferably: relative to the AlN filler 100 The mass of the silicone-based mixed prepolymer is 2 to 10 parts by mass.

The heat dissipation member obtained according to the present invention includes any one of the above-mentioned silicon-oxygen mixed polymer-coated AlN fillers. [Effect of the invention]

As described above, according to the present invention, it is possible to provide a silicon-oxygen mixed polymer-coated AlN filler which exhibits high thermal conductivity and has high heat resistance. Furthermore, according to the present invention, it is possible to provide a heat radiating member which is stable for a long period of time and can be used without being affected by the environment, and there are few cases where characteristics change due to hydrolysis of the filler.

<AlN: Aluminum Nitride> Aluminum nitride is insulating and has high thermal conductivity. The primary particles synthesized by the reduction nitridation method or the direct nitridation method may be used as they are, or they may be granulated by a spray dryer or the like and then sintered to form a so-called AlN sintered filler and used. In the method for granulating using a spray dryer, the particle size of the particles can be controlled by adjusting the spray conditions of the spray dryer, and as a result, AlN sintered fillers having various particle size distributions can be produced. Furthermore, in the present invention, the AlN filler also includes an AlN filler to which a small amount of yttrium oxide (Y ₂ O ₃ ) is added for a sintering aid, and an AlN filler to which a small amount of boron nitride (BN) is added to control a particle diameter. AlN filler.

<Silicon-based Hybrid Polymer Covered AlN Filler> When an AlN filler is dispersed in a resin material to form a heat-radiating member, the silicone-based hybrid polymer is used for coating to suppress the hydrolysis of the filler. The silica-based mixed polymer-coated AlN filler can be added to ion-exchanged water, and treated under pressure using an autoclave or the like. The suppression effect can be evaluated by the conductivity (change) of water at this time. . The inventors have found that if 5 g of AlN filler having an average particle diameter of 20 to 40 μm is added to 50 mL of ion-exchanged water and maintained at a saturated water vapor pressure (2 atmospheres (atm)) of 121 ° C. for 50 hours, When the electrical conductivity is suppressed to 350 μS / cm or less, and if it is more surely suppressed to 230 μS / cm or less, the AlN filler is dispersed in various resin materials such as silicone resin, epoxy resin, and nylon resin, especially the ring. When an oxyresin is used as a heat radiation member, it is possible to sufficiently suppress deterioration of thermal conductivity.

In addition, in the same evaluation, if the pH value of the water is 10 or less, a heat dissipation member can be obtained, and the heat dissipation member can more surely and sufficiently suppress deterioration in thermal conductivity.

<Silica-based hybrid prepolymer> Polydimethylsiloxane (hereinafter referred to as PDMS), which is a raw material of the silicon-based hybrid prepolymer used in the present invention, is preferably represented by the general formula (1) The number average molecular weight (Mn) is 500 to 3000.

Here, m is an integer that satisfies the number-average molecular weight (Mn) = 500 to 3000, and the integer m in a certain range is mixed. Furthermore, it is preferable to use PDMS having both terminal silanol groups (Si-OH groups), but the same effect can also be expected using PDMS having terminal alkoxy groups, and the terminal alkoxy groups easily become silanols by hydrolysis. base.

The viscosity of the prepared silica-based mixed prepolymer will be affected by the average molecular weight of PDMS as a raw material. Therefore, the silica-based mixed prepolymer prepared from high-molecular-weight PDMS is not easy to protect the surface of nitride fillers such as AlN. effect. As a result of the study, a good surface treatment effect was obtained in the range of the number average molecular weight (Mn) from 500 to 3000. When the number average molecular weight (Mn) is less than 500, the softness of the obtained polymer coating becomes insufficient, and the protective layer (coating) is hard, so cracking is liable to occur, and it may become easy to peel off from the surface of the AlN filler. On the other hand, when a silicone-based mixed prepolymer prepared from PDMS having an average molecular weight of more than 3000 is used, it may be impossible to follow the fine unevenness on the surface of the AlN filler due to high viscosity, and it may become difficult to sufficiently adhere. Taking into consideration the softness and adhesion of the protective layer (coating), the average molecular weight of PDMS is more preferably 600 to 2,000.

<Measurement of average molecular weight of polysiloxane (polydimethylsiloxane)> The average molecular weight is measured by a gel permeation chromatography (GPC method), and Mn (number average molecular weight) is set as an average molecular weight. Using polystyrene as a standard sample, the molecular weight in terms of polystyrene was measured. The molecular weight measurement in terms of polystyrene in accordance with the GPC method was performed under the following measurement conditions. a) Measuring machine: HLC-8220GPC manufactured by Tosoh Corporation b) Tubular column: TSK-gel Super H-RC manufactured by Tosoh Corporation 2 TSK-gel Super HZ2000 3 TSK-gel Super HZ4000 1 c) Oven temperature : 40 ° C d) eluent: tetrahydrofuran (THF) 0.35mL / min e) standard sample: polystyrene f) injection volume: 10 μL g) concentration: 1wt% h) preparation sample: using tetrahydrofuran (THF) as a solvent, And let stand at room temperature to dissolve. i) Calibration: When measuring, use a standard sample to make a calibration curve.

Blended as an inorganic component of the siloxane-based mixed prepolymer is an alkoxysilane oligomer represented by the general formula (2) and / or a hydrolyzate thereof.

Here, n is an integer of 4 to 10, and R is an alkyl group selected from 1 to 3 carbon atoms, and all of them may be the same or different. In a preferred form, R is ethyl or methyl. Since some of these alkoxy groups become silanol groups by hydrolysis, a situation in which a hydroxyl group and an alkoxy group are mixed in the molecule can be considered.

The prepared silicon-oxygen mixed prepolymer has a high concentration as a stock solution. When it is used directly, the prepared protective film becomes thick, and the thermal conductivity decreases or the filler agglomerates. Therefore, it is desirable to use a suitable solvent for dilution and surface treatment. The solvent is not particularly limited as long as it has high compatibility with silica-based prepolymers. Toluene, xylene, tertiary butanol, heptane, methyl ethyl ketone, etc. are also preferred, depending on the application or The form of the AlN filler is preferably diluted in such a manner that the silica-based mixed prepolymer becomes 10 wt% or less relative to the total amount of the mixed prepolymer sol after dilution. When the concentration exceeds this concentration, the following problems occur: the effect of sufficiently protecting the fine uneven surface of the AlN surface cannot be obtained, or the thickness becomes a thick film, and the thermal conductivity is deteriorated.

In the surface treatment, an appropriate amount of an AlN filler is blended into a silicone-based mixed prepolymer (sol) solution diluted with the above-mentioned solvent, and the AlN filler surface treatment is performed by stirring. The mixing method is not particularly limited, and various methods such as agitator stirring, mixing stirring by a stirring blade, and planetary biaxial centrifugal stirring can be performed. However, the AlN filler to be subjected to the surface treatment needs to be sufficiently homogeneously dispersed in the diluted mixed prepolymer, and the AlN surface must be sufficiently wetted.

After the above surface treatment, a rotary evaporator or the like is used to volatilize the solvent, and the AlN filler is repeatedly dried, crushed, sintered, and crushed, so as to obtain an AlN filler prepared by surface-treating a silicone-based mixed polymer. In addition, the fracture surface may be exposed during crushing, so it is also desirable to repeat these series of treatments several times.

[Production of a siloxane-based hybrid prepolymer] In the present invention, PDMS represented by the general formula (1) and a tetraalkoxysilane oligomer and / or a hydrolysate thereof (hereinafter (Referred to as a silane oligomer), a silicon-oxygen mixed prepolymer is prepared (about 120 ° C) in the presence of a metal compound catalyst.

Regarding metal compound catalysts, there are: metal organic acid salts (especially carboxylates), alkoxides, alkylated metal compounds, acetamidoacetone complexes, acetoacetate complexes, metal alcohols Metal complexes in which a part of the alkoxy group of the salt is substituted with ethyl acetone or ethyl acetoacetate; specifically, examples include zinc caprylate (zinc 2-ethylhexanoate), caprylic acid Zirconium (zirconyl 2-ethylhexanoate), zirconyl octoate (zirconyl 2-ethylhexanoate), dibutyltin dilaurate, dibutyltin diacetate, bis (ethylacetonyl) dibutyltin, titanate (2-ethylhexyl) ester, titanium tetra-n-butoxide, titanium tetraisopropoxide, titanium diisopropoxy bis (ethyl ethylacetate) titanium, tetra (ethyl ethyl acetone) titanium, di-2 -Ethylhexyloxybis (2-ethyl-3-hydroxyhexanol) titanium, diisopropoxybis (ethylideneacetone) titanium, tetra-n-propanol zirconium, tetra-n-butoxide zirconium, tetra ( Ethyl acetonyl) zirconium, tributoxy monoethyl acetonyl acetonyl zirconium, dibutoxy bis (ethyl ethyl acetoacetate) zirconium, and the like. Although not particularly limited, from the viewpoints of reactivity and stability, tin (Sn) -based catalysts, that is, dibutyltin dilaurate, dibutyltin diacetate, bis (ethylacetonyl) dibutyltin, etc. .

When carrying out the above-mentioned condensation reaction, in order to carry out stable hydrolysis of the tetraalkoxysilane oligomer, it is preferable to perform the hydrolysis and condensation reaction by heating in an atmosphere filled with an inert gas in the container used for the reaction. . Examples of the inert gas include nitrogen or a rare gas, that is, a group 18 element (helium, neon, argon, krypton, xenon, etc.). These gases can be used in combination. As a method of hydrolysis, various methods can be considered: dripping, spraying an appropriate amount of water, and introducing water vapor or the like. Depending on the situation, the following synthesis methods may be considered: sending dry air that has been subjected to humidity management into a synthesis container, and reducing the pressure at regular intervals.

The silica-based mixed prepolymer can be obtained by hydrolyzing a mixture containing the tetraalkoxysilane oligomer and the PDMS in the presence of the condensation catalyst under the inert gas atmosphere. And condensation reaction. That is, the alkoxy group of the tetraalkoxysilane oligomer after hydrolysis becomes a silanol group, and undergoes dehydration reaction, dealcoholization reaction, and the like with a silanol group at the end of PDMS in the presence of an inert gas. By using a silane oligomer, it is possible to smoothly perform a condensation reaction between PDMS and a hydrolyzed oligomer without accelerating homocondensation easily generated by a silane monomer. Thereby, the said oligomer and the said PDMS are reacted homogeneously, and a condensation reaction progresses smoothly.

In addition, from the viewpoint of long-term stability and the like, it is also desirable to add a stabilizing solvent to a raw material liquid under the above-mentioned inert gas atmosphere when obtaining the above-mentioned silicon-oxygen mixed prepolymer. It consists of a mixture of the alkoxide and PDMS. As this stabilizing solvent, tertiary butanol, heptane, toluene, xylene, methyl ethyl ketone and the like are also highly compatible, and they can also be used as a diluting solvent in the manner described above.

[Blending ratio] The blending ratio of the PDMS and the tetraalkoxysilane oligomer (PDMS / silane oligomer) is preferably set to a molar ratio of 0.05 to 5 (PDMS / silane oligomer). (1 = 20 to 1 / 0.2), preferably in the range of 0.125 to 2.0 (PDMS / silane oligomer = 1/8 to 1 / 0.5), and more preferably in the range of 0.25 to 1.0 (PDMS / silane oligomer = 1/4 to 1/1). However, it is desirable to change the blending ratio in accordance with the functional group amount of the AlN filler used. When the amount of functional groups is large, it is desirable to increase the blending ratio of the tetraalkoxysilane oligomer within the above range. If the molar ratio of the PDMS / oligomer is within the above range, the dehydration condensation reaction can be smoothly performed, and gelation during or after the reaction becomes difficult to occur, so that it is difficult for the gelation to occur, and It is possible to obtain a stable sol without low molecular weight siloxane residues.

In addition, the molar ratio mentioned here refers to a molar ratio calculated based on the number average molecular weight (Mn) of PDMS and the purity and average molecular weight of the oligomer of tetraalkoxysilane, and the number of PDMS The average molecular weight was determined by gel permeation chromatography (GPC method) using polystyrene as a standard material and tetrahydrofuran as an eluent.

<Surface treatment of AlN filler> The silicon-based mixed prepolymer is 2 to 10 parts by mass, and more preferably 2.5 to 6 parts by mass with respect to 100 parts by mass of the AlN filler. The prepolymer sol was mixed into the AlN filler and subjected to agitation and mixing treatment. The treatment is continued at room temperature for 5 hours or more, preferably 10 hours or more, and more preferably 24 hours or more. Then, the solvent was removed under reduced pressure to obtain an AlN aggregate with a prepolymer mixed on the surface. By heat-treating the agglomerates, an AlN filler can be obtained. The AlN filler has a mixed prepolymer hardened layer formed on the surface and has high durability. Since this AlN filler is excellent in water resistance, when it is added to a hydrophilic resin such as an epoxy resin, characteristics such as thermal conductivity are not deteriorated.

Compared with the conventional method, that is, when various coupling agents, silicone oils, and silicone resins are used, the silicone-based hybrid polymer-coated AlN filler of the present invention has very high water resistance, and does not include a phosphoric acid-based treatment agent. Such a component that corrodes metal members can also be used for hydrophilic resins such as epoxy resins, or water-absorbent resins such as silicone rubber and nylon resin, and can be used in applications where the use or application is not limited. use. Furthermore, the flexible film does not break even in high-stress processing such as kneading resin. [Example]

The present invention will be described more specifically using examples. In addition, "part" and "%" in an Example are based on mass (mass part, mass%) as long as there is no special description. The present invention is not limited to these examples at all.

<Synthetic silica-based mixed prepolymer> (Preparation of liquid A) The reaction vessel equipped with a stirring device, a thermometer, and a dripping line is sufficiently filled with nitrogen. At this time, as the nitrogen gas, nitrogen gas produced by a nitrogen production apparatus (UNX-200 manufactured by Japan Unix Corporation) was used. The synthesis was carried out on a scale of about 1 kg using a 2L container.

Then, in the reaction vessel sufficiently filled with the nitrogen gas, a polydimethylsiloxane (PDMS) having a silanol group at both ends and an oligomer with a tetraalkoxysilane were charged into the reaction vessel, and After the synthesis vessel was heated up to 120 ° C, a condensation catalyst was added, and the reaction was further stirred at 120 ° C for 30 minutes. Then, it was left to cool to room temperature, and tertiary butanol was mixed as a diluting solvent to obtain a liquid A.

(Preparation of liquid B) A tetraalkoxysilane oligomer and an organometallic compound were put into a reaction container different from the above, and stirred at room temperature to obtain a transparent liquid B.

(Example 1) (Preparation of liquid A-1) The raw materials used were: PDMS, a two-terminal silanol polydimethylsiloxane XC96-723 (number average molecular weight: Mn = 680) manufactured by Momentive; Teethoxysilane (TEOS) oligomer is ethyl silicate, Silicate 40 (tetraethoxysilane straight-chain 4-6 polymer, also known as oligomer, manufactured by Tama Chemical Industry Co., Ltd. Polymer purity: 70% by mass, average molecular weight: 745); dilute solution, tertiary butanol (manufactured by Wako Pure Chemical Industries, Ltd., Wako special grade); condensation catalyst, dibutyltin dilaurate (Kyoto Pharmaceutical Co., Ltd. Co., Ltd. (KS-1260); and synthesis was performed on a scale of about 1 kg. The blending amount of each raw material is as follows.

Molar ratio: PDMS (XC96-723) is 185.6 g, TEOS oligomer (Silicate 40) is 813.4 g, and the molar ratio of pure oligomer components of XC96-723 and Silicate 40 is 1: 2.8. 1.0 g of dibutyltin dilaurate was added as a condensation catalyst. 150 g of tertiary butanol was blended as a dilution solvent.

(Preparation of liquid B) The raw materials used are: TEOS oligomer, Silicate 45 (tetraethoxysilane straight-chain 8 to 10 polymer, also known as oligomer, oligomer) manufactured by Tama Chemical Industry Co., Ltd. Material purity: 95% by mass, average molecular weight: 1282); organometallic compound, zinc 2-ethylhexanoate (NIKKA OCTHIX ZINC manufactured by Nippon Chemical Industry Co., Ltd. 18%, molecular weight: 351.79); diluted solution, three Butanol. The blending amount is as described below.

Molar ratio: 76 g of TEOS oligomer (Silicate 45) and 24 g of zinc 2-ethylhexanoate (NIKKA OCTHIX ZINC 18%). The molar ratio of Ethyl Silicate 45 to zinc 2-ethylhexanoate is 1: 1.2. 10 g of tertiary butanol was blended as a dilution solvent.

(Preparation of surface treatment agent C-1 liquid) The total amount of the A-1 liquid and the total amount of the B liquid were mixed and stirred to obtain a C-1 liquid.

(Surface treatment method) The C-1 solution was added to 100 parts by mass of a filler (aluminum nitride: FAN-f30 manufactured by Furukawa Electronics Co., Ltd., with an average particle diameter of about 30 μm) and 3 parts by mass of the prepolymer. 100 parts by mass of tertiary butanol was further added, and the mixture was stirred at 40 ° C. for 24 hours, and then dried under reduced pressure on a rotary evaporator to make it into a powder state. Then, heat treatment was performed at 200 ° C for 4 hours, and further disintegration treatment was performed. The average particle diameter of the AlN filler coated with the silica-based mixed polymer was also about 30 μm.

The average particle diameter was measured dry using a laser diffraction particle size distribution measuring device MASTERSIZER 3000 manufactured by Spikey Corporation.

(Examples 2 to 4) (Preparation of liquids A-2, 3, and 4) The raw materials used were: PDMS, a two-terminal silanol polydimethylsiloxane XC96-723 (number average molecular weight) manufactured by Momentive. : Mn = 680); TEOS oligomer is ethyl silicate, Silicate 45 (tetraethoxysilane straight-chain 8 to 10 polymer, also known as oligomer, oligomer) manufactured by Tama Chemical Industry Co., Ltd. Material purity: 95% by mass, average molecular weight: 1282); diluted solution, tertiary butanol (manufactured by Wako Pure Chemical Industries, Ltd., Heguang Special Grade); condensation catalyst, dibutyltin dilaurate (Kyodo Pharmaceutical Co., Ltd. limited) KS-1260 manufactured by the company); and synthesis was performed on a scale of about 1 kg. The blending amount of each raw material is as follows.

Liquid A-2: Molar ratio, PDMS (XC96-723) is 117.0g, TEOS oligomer (Silicate 45) is 882.4g, and the molar ratio of pure oligomer components of XC96-723 and Silicate 45 is 1 : 3.8. 0.65 g of dibutyltin dilaurate was added as a condensation catalyst. 150 g of tertiary butanol was blended as a dilution solvent.

Liquid A-3: Molar ratio, PDMS (XC96-723) is 209.4g, TEOS oligomer (Silicate 45) is 789.5g, and the molar ratio of pure oligomer components of XC96-723 and Silicate 45 is 1 : 1.9. As a condensation catalyst, 1.2 g of dibutyltin dilaurate was added. 150 g of tertiary butanol was blended as a dilution solvent.

Liquid A-4: Molar ratio, PDMS (XC96-723) is 150.1g, TEOS oligomer (Silicate 45) is 849.0g, and the molar ratio of pure oligomer components of XC96-723 and Silicate 45 is 1 : 2.9. 0.8 g of dibutyltin dilaurate was added as a condensation catalyst. 150 g of tertiary butanol was blended as a dilution solvent.

(Preparation of liquids C-2, 3, and 4) The total amount of each of liquids A-2, 3, and 4 and the total amount of liquid B were mixed and stirred to obtain liquids C-2, 3, and 4.

(Surface treatment method) C-2, 3, and 4 liquids were added to 100 parts by mass of the filler (aluminum nitride: FAN-f30 manufactured by Furukawa Electronics Co., Ltd.), and 3 parts by mass of the prepolymer were further added. After adding 100 parts by mass of tertiary butanol and stirring at 40 ° C. for 24 hours, it was dried under reduced pressure on a rotary evaporator to make it into a powder state. Then, heat treatment was performed at 200 ° C for 4 hours, and further disintegration treatment was performed. The average particle diameter of the AlN filler coated with the siloxane-based mixed polymer was also about 30 μm.

(Example 5) (Preparation of liquid A-5) The raw materials used were: PDMS, a two-terminal silanol polydimethylsiloxane DMS-S14 (number average molecular weight: Mn = 1500) manufactured by Gelest Company; TEOS oligomer is ethyl silicate, Silicate 45 (tetraethoxysilane linear 8 to 10 oligomer is also an oligomer, manufactured by Tama Chemical Industry Co., Ltd., purity of oligomer: 95% by mass , Average molecular weight: 1282); dilute solution, tertiary butanol (manufactured by Wako Pure Chemical Industries, Ltd., Heguang special grade); condensation catalyst, dibutyltin dilaurate (KS-1260, manufactured by Kyoho Pharmaceutical Co., Ltd.) ); And the synthesis was performed on a scale of about 1 kg. The blending amount of each raw material is as follows.

Molar ratio: PDMS (DMS-S14) is 226.2 g, TEOS oligomer (Silicate 45) is 773.2 g, and the molar ratio of pure oligomer components of DMS-S14 and Silicate 45 is 1: 3.8. 0.6 g of dibutyltin dilaurate was added as a condensation catalyst. 150 g of tertiary butanol was blended as a dilution solvent.

(Preparation of liquid C-5 for surface treatment) The total amount of liquid A-5 and the total amount of liquid B were mixed and stirred to obtain a liquid C-5.

(Surface treatment method) The amount of the prepolymer was set to 5 parts by mass, and in the same manner as in the case of the C-1 to C-4 liquid, the filler was filled with the C-5 liquid (aluminum nitride: FAN- manufactured by Furukawa Electronics Co., Ltd.). f30) performing surface treatment to obtain an AlN filler coated with a silicon-oxygen-based hybrid polymer having an average particle diameter of about 30 μm.

(Comparative Example 1) (Preparation of liquid A-6) The raw material used was: PDMS, a two-terminal silanol polydimethylsiloxane DMS-S15 (number average molecular weight: Mn = 3500) manufactured by Gelest Company; The oligomer is ethyl silicate, Silicate 45 (tetraethoxysilane, linear 8 to 10 oligomer, also known as oligomer, manufactured by Tama Chemical Industry Co., Ltd., purity of oligomer: 95% by mass, Average molecular weight: 1282); Diluted solution is tertiary butanol (manufactured by Wako Pure Chemical Industries, Ltd., Wako special grade); condensation catalyst is dibutyltin dilaurate (KS-1260 manufactured by Kyoho Pharmaceutical Co., Ltd.) And carry out the synthesis on a scale of about 1 kg. The blending amount of each raw material is as follows.

Molar ratio: PDMS (DMS-S15) is 405.5 g, TEOS oligomer (Silicate 45) is 594.1 g, and the molar ratio of pure oligomer components of DMS-S15 and Silicate 45 is 1: 3.8. 0.4 g of dibutyltin dilaurate was added as a condensation catalyst. 150 g of tertiary butanol was blended as a dilution solvent.

(Preparation of surface treatment agent C-6 liquid) The total amount of the A-6 liquid and the total amount of the B liquid were mixed and stirred to obtain a C-6 liquid.

(Surface treatment method) The amount of the prepolymer was set to 10 parts by mass, and in the same manner as in the case of the C-1 to C-4 liquid, the filler was filled with the C-6 liquid (aluminum nitride: FAN- manufactured by Furukawa Electronics Co., Ltd.). f30) performing surface treatment to obtain an AlN filler coated with a silicon-oxygen-based hybrid polymer having an average particle diameter of about 30 μm.

(Comparative Example 2) (Preparation of liquid A-7) PDMS was a two-terminal silanol polydimethylsiloxane FM9915 (number average molecular weight: Mn = 5000) manufactured by JNC, and TEOS oligomer was ethyl silicate. Ester, Silicate 40 (straight-chain 4 to 6 polymer of tetraethoxysilane, which is an oligomer, purity of oligomer: 70% by mass, average molecular weight: 745) manufactured by Tama Chemical Industry Co., Ltd., diluted solution It uses tertiary butanol (manufactured by Wako Pure Chemical Industries, Ltd., and Wako special grade), and the condensation catalyst is dibutyltin dilaurate (KS-1260 manufactured by Kyoho Pharmaceutical Co., Ltd.). Implement synthesis. The blending amount of each raw material is as follows.

Molar ratio: PDMS (FM9915) is 626.3 g, TEOS oligomer (Silicate 40) is 373.3 g, and the molar ratio of pure oligomer components of FM9915 and Silicate 40 is 1: 2.8. 0.5 g of dibutyltin dilaurate was added as a condensation catalyst. 150 g of tertiary butanol was blended as a dilution solvent.

(Preparation of surface treatment agent C-7 liquid) The total amount of the A-7 liquid and the total amount of the B liquid were mixed and stirred to obtain a C-7 liquid.

(Surface treatment method) The amount of the prepolymer was set to 10 parts by mass, and in the same manner as in the case of the C-1 to C-4 liquids, the filler was filled with the C-7 liquid (aluminum nitride: FAN- manufactured by Furukawa Electronics Co., Ltd.). f30) performing surface treatment to obtain an AlN filler coated with a silicon-oxygen-based hybrid polymer having an average particle diameter of about 30 μm.

(Comparative Example 3) (Preparation of A-8 'solution) PDMS was a two-terminal silanol polydimethylsiloxane FM9926 (number average molecular weight: Mn = 20,000) manufactured by JNC, and ethyl silicate was used for the oligomer. Ester, Silicate 40 (straight-chain 4 to 6 polymer of tetraethoxysilane, which is an oligomer, purity of oligomer: 70% by mass, average molecular weight: 745) manufactured by Tama Chemical Industry Co., Ltd., diluted solution It uses tertiary butanol (manufactured by Wako Pure Chemical Industries, Ltd., and Wako special grade), and the condensation catalyst is dibutyltin dilaurate (KS-1260 manufactured by Kyoho Pharmaceutical Co., Ltd.). Implement synthesis. The blending amount of each raw material is as follows.

Molar ratio: PDMS (FM9926) is 609.1 g, oligomer (Silicate 40) is 90.8 g, and the pure oligomer component of Silicate 40 with respect to FM9926 is 1: 2.8. As a condensation catalyst, 0.18 g of dibutyltin dilaurate was added. As a dilution solvent, 105 g of tertiary butanol was blended. (Preparation of A-8 solution) 345 g of the A-7 solution used in Comparative Example 3 and 805 g of the A-8 'solution were mixed to prepare 1150 g of a sol, and the solution was set to A-8 solution.

(Preparation of surface treatment agent C-8 liquid) The total amount of the A-8 liquid and the total amount of the B liquid were mixed and stirred to obtain a C-8 liquid.

(Surface treatment method) The amount of the prepolymer was set to 10 parts by mass, and in the same manner as in the case of the C-1 to C-4 liquids, the filler was filled with the C-8 liquid (aluminum nitride: FAN- manufactured by Furukawa Electronics Co., Ltd.). f30) performing surface treatment to obtain an AlN filler coated with a silicon-oxygen-based hybrid polymer having an average particle diameter of about 30 μm.

(Comparative example 4) It is set as low molecular weight and does not contain a PDMS component, and only surface treatment is performed with a TEOS oligomer component. The raw materials used are TEOS oligomers (Silicate 45 manufactured by Tama Chemical Industry Co., Ltd., linear 8 to 10 oligomers of tetraethoxysilane, that is, oligomers, oligomer purity: 95% by mass , Average molecular weight: 1282).

(Surface treatment method) Silicate 45 manufactured by Tama Chemical Industry Co., Ltd. is added so that 100 parts by mass of filler (aluminum nitride: FAN-f30 manufactured by Furukawa Electronics Co., Ltd.) becomes 10 parts by mass, and heating is performed while heating After being stirred and dried, it was brought into a powder state. Then, a final heat treatment was performed at 200 ° C. for 4 hours to obtain an AlN filler coated with a silicone-based mixture having an average particle diameter of about 30 μm.

(Comparative Examples 5 to 7) As the aluminum nitride filler without surface treatment, H Grade (average particle diameter: 1 μm), FAN-f30 (average particle diameter: 30 μm), and FAN-f80 (average particle diameter: 80 μm) were prepared. Three types (all manufactured by Furukawa Electronics).

<Evaluation Method> [About pH measurement method and conductivity measurement method] 5 g of each surface-treated AlN filler prepared in Examples 1 to 5 and Comparative Examples 1 to 4 and each surface prepared in Comparative Examples 5 to 7 were untreated. The AlN filler was put into a container made of polytetrafluoroethylene, and 50 mL of ion-exchanged water was added. Then, the mouth of the glass container was covered with aluminum foil, and kept in an autoclave at 121 ° C. for 50 hours. Then, it stood still until it became normal temperature, and measured the pH value and electrical conductivity of a filtrate.

The pH value and the electrical conductivity are values of water before and after treatment using a pH composite measuring device manufactured by Eutech. The compositions and evaluation results of the examples and comparative examples are summarized and shown in Tables 1 to 3.

[Table 1]

[Table 2]

[table 3]

<Evaluation Results> As can be seen from the results of pH and electrical conductivity, compared to the surface-treated fillers of Comparative Examples 1 to 4, an AlN filler (coated with a silicone-based hybrid polymer) prepared by the following method (Example) 1 to 5) Hydrolysis is suppressed: PDMS having a number average molecular weight of 1500 or less is used as a PDMS as a raw material, and a condensation reaction with a TEOS oligomer is performed. An AlN filler (Comparative Examples 1 to 3) coated with a silica-based mixed polymer prepared by the following method has a small effect of suppressing hydrolysis: PDMS having a number average molecular weight of 3500 or more is used as a PDMS as a raw material. In addition, an AlN filler (Comparative Example 4) using only TEOS oligomer was not as flexible as the film, and therefore was equivalent to an untreated filler (Comparative Examples 5 to 7). Furthermore, it can be seen from the results of the untreated AlN filler that the particle size is not greatly affected in the case where the pH value changes and the conductivity changes due to surface hydrolysis.

<Evaluation of Thermal Conductivity of Heat Dissipating Member> (Evaluation 1) As an example of a heat dissipating member containing a silicone-based hybrid polymer-coated AlN filler obtained in accordance with the present invention, a thermally conductive sheet was produced in the following manner. That is, 10 parts of a hardener (AJICURE AH-154 made by Ajinomoto Fine-Techno Co., Ltd.) and 320 parts of a silicon-oxygen mixed polymer obtained in Example 3 with an average particle diameter of about 30 μm were coated with AlN. The filler (AlN filler: FAN-f30 manufactured by Furukawa Electronics Co., Ltd.) was put into a polypropylene beaker containing 100 parts of epoxy resin (epikote 828 epoxy resin manufactured by Mitsubishi Chemical Corporation), and the Its homogeneous way was mixed with a propeller agitator for 10 minutes. A ceramic three-roll mill was used to further knead the obtained compound for 10 minutes and was recovered. The recovered composite was sandwiched with a polymethylpentene resin film, and formed into a sheet shape having a size of about 100 mm × 150 mm and a thickness of 0.5 mm by a stretching roll. The formed sheet was heated at 150 ° C. for 6 hours in a warm air circulation dryer to obtain a rubber sheet-like heat conductive sheet. The thermal conductivity of this sheet is 3.0 W ･ m ^-1 ･ K ^-1 .

This heat conductive sheet was subjected to a pressure cooker test for 200 hours (PCT, pure water and sample sheets were placed in an autoclave, under the conditions of 121 ° C. × 100% relative humidity (RH), 2 atm), and then the thermal conductivity was measured. As a result of measurement, it was 3.0 W ･ m ^-1 ･ K ^-1 . No deterioration was confirmed.

(Evaluation 2) The silicone-based hybrid polymer-coated AlN filler obtained in Example 2 was used as the silicone-based hybrid polymer-coated AlN filler, and the same procedure as in Evaluation 1 was performed to obtain a rubber sheet-like heat conductive sheet. The thermal conductivity of this sheet is 3.0 W ･ m ^-1 ･ K ^-1 .

This thermally conductive sheet was subjected to PCT for 200 hours (filled with pure water and sample sheet in an autoclave under the conditions of 121 ° C × 100% RH, 2 atm), and the thermal conductivity was measured. The result was 2.8 W2.8m ^-1 ･ K ^-1 . Hardly any deterioration was observed.

In Evaluation 1 and Evaluation 2, the thermal conductivity was measured using T3ster DynTIM manufactured by Mentor Graphics Japan, and performed in accordance with American Society for Testing and Materials (ASTM) D5470. Samples having a diameter of 12.8 mm and a thickness of 0.35 mm, 0.5 mm, 0.6 mm, 0.7 mm, and 0.8 mm were prepared. A predetermined load was applied to the sample, and the thermal resistance value was measured from the temperature difference between the upper and lower (thickness direction) and electric power. From the graphs of the thickness and thermal resistance of the above five samples, the contact thermal resistance component and the thermal resistance component of the sheet were separated, and the thermal resistance component of the sheet was linearly approximated, and then the thermal conductivity was calculated from the obtained thermal resistance value.

[Modifications] The present invention is not limited to the above embodiments, as long as those with ordinary knowledge in the technical field of the present invention can understand from the scope of the patent application and the description and do not violate the technical idea of the present invention, they can be changed, deleted, and added.

As the PDMS, as long as the number average molecular weight is within the range, PDMS having different molecular weight distributions can be used. For example, when PDMS with a narrow molecular weight distribution and uniform molecular weight is used, a silicone-based hybrid prepolymer having very few unreacted sites can be obtained, and characteristics such as durability and surface water repellency can be exhibited.

The inert gas used when the atmosphere in the reaction vessel is replaced may be an inert gas having a purity of 80% or more and a moisture content of 20% or less.

The present invention can be summarized as follows.

(1) A silica-based polymer-coated AlN filler obtained in accordance with the present invention is a filler containing aluminum nitride whose surface is coated with a silica-based polymer as a main component, and 50 mL of ion-exchanged water After adding 5 g of the filler having an average particle diameter of 20 to 40 μm, and maintaining it at a saturated water vapor pressure of 121 ° C. for 50 hours, the conductivity of water is 350 μS / cm or less.

(2) The silica-based hybrid polymer-coated AlN filler obtained according to the present invention is preferably: for 50 mL of ion-exchanged water, 5 g of the filler having an average particle diameter of 20 to 40 μm is added, and the saturated water is at 121 ° C. After the vapor pressure was maintained for 50 hours, the pH of the water was 10 or less.

(3) In the silica-based hybrid polymer-coated AlN filler obtained according to the present invention, it is preferred that the silica-based hybrid polymer is a cured product containing the following formula (1) Reactant of polydimethylsiloxane with a tetraalkoxysilane oligomer and / or its hydrolysate represented by the following general formula (2), the number average molecular weight of the polydimethylsiloxane (Mn ) Is 500 ～ 3000; m is an integer capable of satisfying the number average molecular weight (Mn) = 500-3000, and mixed with an integer m within a certain range; n represents an integer of 4 to 10, and R represents an alkyl group having 1 to 3 carbon atoms.

(4) In the silica-based hybrid polymer-coated AlN filler obtained according to the present invention, the number average molecular weight (Mn) of the polydimethylsiloxane represented by the general formula (1) is preferably 600 to 2000. .

(5) The silica-based hybrid polymer-coated AlN filler obtained according to the present invention preferably has an average particle diameter of 25 to 35 μm.

(6) The mass ratio of the silica-based hybrid polymer-coated AlN filler obtained according to the present invention to the silica-based hybrid polymer-coated AlN filler and the silica-based prepolymer is preferably: The AlN filler is 100 parts by mass, and the silica-based mixed prepolymer is 2 to 10 parts by mass.

(7) The heat-dissipating member according to the present invention includes the silicon-oxygen mixed polymer-coated AlN filler as described in any one of (1) to (6) above. [Industrial availability]

If the silica-based hybrid polymer coated AlN filler obtained according to the present invention is used, a heat dissipation member or functional member can be obtained, which is less affected by the environment, that is, due to hydrolysis of the surface of the AlN filler Since there are few cases where characteristics such as thermal conductivity are reduced, it is possible to design a material which is superior in both heat resistance, flexibility, and high thermal conductivity.

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Claims (7)

A silicon-oxygen mixed polymer-coated aluminum nitride filler is a filler containing aluminum nitride coated on the surface with a silicon-oxygen mixed polymer as a main component, and 5 g of average particle size is added to 50 mL of ion-exchanged water. After the filler is 20 to 40 μm and is maintained at a saturated water vapor pressure of 121 ° C. for 50 hours, the conductivity of water is 350 μS / cm or less. The silicon-oxygen mixed polymer-coated aluminum nitride filler according to claim 1, wherein 50 g of ion-exchanged water is added with 5 g of the filler having an average particle diameter of 20 to 40 μm, and the saturated water vapor pressure is 121 ° C. After holding for 50 hours, the pH of the water was 10 or less. The silica-based hybrid polymer-coated aluminum nitride filler according to claim 1 or claim 2, wherein the silica-based hybrid polymer is a cured product containing the following general formula (1) The number-average molecular weight of the polydimethylsiloxane represented by the reaction between the polydimethylsiloxane represented by the following general formula (2) and a tetraalkoxysilane oligomer and / or a hydrolyzate thereof: Mn is 500 ～ 3000; m is an integer capable of satisfying the number-average molecular weight Mn = 500-3000, and mixed with an integer m within a certain range; n represents an integer of 4 to 10, and R represents an alkyl group having 1 to 3 carbon atoms. The silicon-oxygen mixed polymer-coated aluminum nitride filler according to claim 3, wherein the number average molecular weight Mn of the polydimethylsiloxane represented by the general formula (1) is 600 to 2000. The siloxane-based mixed polymer-coated aluminum nitride filler according to any one of claim 1 to claim 4, wherein the average particle diameter is 25 to 35 μm. The silica-based hybrid polymer-coated aluminum nitride filler according to any one of claim 1 to claim 5, wherein the aluminum nitride filler to be coated with the aforementioned silica-based hybrid polymer is mixed with a silica-based pre- The mass ratio of the polymer is 2 to 10 parts by mass based on 100 parts by mass of the aluminum nitride filler. A heat dissipation member comprising the silicon-oxygen-based hybrid polymer-coated aluminum nitride filler according to any one of claim 1 to claim 6.