Composite powder

Abstract

One aspect of the present invention pertains to a method for producing a composite powder, the method comprising: (a) a step for providing a powder of a compound containing at least one selected from the group consisting of Zn, Mg, and P, the compound being a negative thermal expansion material; (b) a step for mixing 0.01-50 parts by mass of an oxide of an element including at least one selected from the group consisting of Li, B, and elements each belonging to group 5 or group 6 of the periodic table, with 100 parts by mass of the powder of the compound provided in said step (a) to form a powder mixture; and (c) a step for sintering the powder mixture formed in said step (b) to obtain a composite powder. The oxide may include at least one oxide of an element selected from the group consisting of V, Nb, Ta, Cr, Mo, and W each belonging to group 5 or group 6 of the periodic table.

Description

Composite powder

[0001] The present invention relates to a method for producing a novel composite powder having a spherical particle shape. The present invention also relates to a method for producing a resin composition and a powder mixture containing the spherical composite powder. Further, the present invention relates to a method for producing an electronic component using the resin composition containing the spherical composite powder.

[0002] In recent years, in technical fields that require high precision such as highly developed electronic devices, optical devices, fuel cells, and sensors, control and suppression of thermal expansion of solid materials have been strongly demanded. In particular, when constructing precision devices such as semiconductor devices that require high precision at the nanometer level by combining multiple materials, if displacement, interface peeling, disconnection, warping, cracks, etc. occur due to the difference in the coefficient of thermal expansion between the materials, it may become a serious problem. Therefore, a technique for highly controlling thermal expansion is required.

[0003] While many substances thermally expand with an increase in temperature, it is also known that there are rare negative thermal expansion materials having a negative coefficient of thermal expansion with the property that the volume decreases with an increase in temperature. As one of the techniques for controlling the thermal expansion of precision devices, for example, a technique for controlling the coefficient of thermal expansion of the entire device by adding a negative thermal expansion material in combination with a matrix material (resin, glass, metal, etc.) having a large positive coefficient of thermal expansion and a material (e.g., silica) having a low positive coefficient of thermal expansion as required has attracted attention. Examples of negative thermal expansion materials include, for example, β-eucryptite, zirconium tungstate (ZrW ２ O ８ ), zirconium tungstophosphate (Zr ２ WO ４ (PO ４ ) ２ ), Zn ｘ Cd １－ｘ (CN) ２ , manganese nitride, bismuth nickel ferrite, etc. are known.

[0004] For example, in Patent Document 1, zirconium oxide ZrO ３ is used for tungsten trioxide WO ２The negative thermal expansion material Zr is characterized by mixing raw materials in a stoichiometric ratio such that the sum of the substitution element X with the substitution amount x is 1 molar ratio, forming a powder with a polarized particle size distribution consisting of small particles with a predetermined particle size range and large particles with a predetermined particle size range, and then placing the raw material powder into a desired mold and sintering it. （１－ｘ） X ｘ W ２ O ８ A method for synthesizing (where X is a substitution element for zirconium Zr, 0 ≤ x << 1) has been reported. Patent Document 1 states that this synthesis method has the effect of synthesizing large, high-density heat-shrinkable ceramics without press molding of the raw material powder. In addition to Patent Document 1, development is underway on new negative thermal expansion materials with various compositions and properties, as well as methods for manufacturing them.

[0005] For example, Patent Document 2 reports a negative thermal expansion material containing an oxide represented by a general formula that includes at least one element selected from Mg, Al, Zn, etc., and / or Cu, V, and P. Patent Document 3 reports a lead sealing glass and magnesium pyrophosphate (Mg ２ P ２ O ７ Mill additives of pyrophosphate crystalline materials consisting of ) particularly MgO and P present in approximately stoichiometric molar ratios of magnesium pyrophosphate. ２ O ５ A sealing material having a negative coefficient of thermal expansion has been reported, which includes crystallized glass that is essentially made from. Patent Document 4 describes a material that is substantially P ２ O ５ Negative thermal expansion materials consisting of crystalline phosphate glass particles with one cation selected from magnesium, zinc, aluminum, etc., and mixtures of organic polymers have been reported. Patent document 5 reports modified zirconium tungstate phosphate, which is a negative thermal expansion material whose surface is coated with an inorganic compound containing one or more elements selected from Zn, Mg, V, etc., and it is shown that the amount of phosphorus ions eluting from modified zirconium tungstate phosphate under predetermined conditions can be suppressed by such surface modification.

[0006] Japanese Patent Publication No. 2003-342075, International Publication No. 2022 / 114004, U.S. Patent No. 5089445, Japanese Patent Publication No. Hei 08-048809, Japanese Patent Publication No. 2020-147486

[0007] For example, in precision equipment such as semiconductor devices that require high-precision thermal expansion control, the actual operating temperature during the heat cycle of the equipment is often below 150°C. Therefore, there is a need for materials that exhibit negative thermal expansion characteristics in such temperature ranges. However, many conventional negative thermal expansion materials only exhibit negative thermal expansion characteristics when they reach temperatures above 150°C. Consequently, research is ongoing to find specific compositions of negative thermal expansion materials that exhibit negative thermal expansion characteristics in lower temperature ranges, such as below 150°C, and preferably achieve a higher thermal contraction rate (i.e., a lower negative thermal expansion rate).

[0008] Furthermore, as described above, negative thermal expansion materials can be used in mixture with matrix materials (resins, glass, metals, etc.). When negative thermal expansion materials are used in precision equipment such as semiconductor devices, it is preferable to suppress the increase in viscosity of the resin composition containing the negative thermal expansion material and matrix resin, and to have high fluidity, from the viewpoint of the moldability of the semiconductor device. However, unfortunately, because negative thermal expansion materials have an angular shape (i.e., low particle circularity), the viscosity of the resin composition can increase, and the fluidity can decrease significantly. Therefore, there is a need to provide a method for producing negative thermal expansion materials that have high circularity and do not cause a decrease in fluidity or an increase in viscosity of the resin composition even when mixed with a matrix resin. In addition, there is a need for an efficient manufacturing method that includes a firing process at a lower temperature (i.e., a manufacturing method that is energy-efficient and simple).

[0009] Therefore, the object of the present invention is to provide a method for efficiently producing a novel composite powder with high circularity.

[0010] As a result of diligent research, the inventors discovered that a composite powder with high circularity can be obtained efficiently by mixing a specific oxide with a compound powder that is a negative thermal expansion material and firing it, thus completing the method for producing the composite powder of the present invention.

[0011] In other words, embodiments of the present invention are as follows: [1] A method for producing a composite powder, comprising the steps of: (a) providing a powder of a compound comprising at least one selected from the group consisting of Zn, Mg, and P, wherein the compound is a negative thermal expansion material; (b) mixing an oxide of an element comprising at least one selected from the group consisting of an element belonging to group 5 or 6 of the periodic table, Li, and B, in an amount of 0.01 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the powder of the compound provided in step (a), to form a mixed powder; and (c) obtaining a composite powder by calcining the mixed powder formed in step (b). [2] The method according to [1], wherein the oxide used in step (b) comprises at least one oxide selected from the group consisting of V, Nb, Ta, Cr, Mo, and W belonging to group 5 or 6 of the periodic table. [3] The method according to [1], wherein the oxide used in step (b) comprises at least one oxide selected from the group consisting of V and Mo belonging to group 5 or 6 of the periodic table. [4] The method according to [1], wherein the oxide used in step (b) comprises an oxide having a melting point of 650°C or more and 950°C or less. [5] The method according to [1], wherein the oxide used in step (b) comprises an oxide that is in powder or liquid form. [6] The method according to [1], wherein the circularity of the composite powder is 0.75 or more and 1.00 or less. [7] The method according to [1], wherein the content of uranium (U) and thorium (Th) in the composite powder is 1 ppm by mass or less, and the content of lead (Pb) and bismuth (Bi) in the composite powder is 30 ppm by mass or less. [8] A method for producing a resin composition, comprising obtaining a resin composition by combining the composite powder and resin component described in [1]. [9] The method according to [8], further comprising obtaining a resin composition by combining the composite powder and resin component described in [1] with a curing agent.

[10] The α dose of the resin composition is 0.0200 cph / cm². ２The method according to [8], which is as follows:

[11] A method for producing a powder mixture, comprising combining the composite powder described in [1] with silica powder or other thermally conductive powder to obtain a powder mixture.

[12] A method using the resin composition described in [8], comprising sealing an electronic component with the resin composition.

[13] A method using the resin composition described in [8], comprising sealing an electronic component with the resin composition as underfill.

[14] A method for producing an electronic component, comprising obtaining a resin composition by combining the composite powder described in [1] with a resin component, applying the resin composition to a first member, applying a second member to the resin composition simultaneously with or after the application of the resin composition to the first member to obtain a component assembly in which the resin composition is sealed between the first and second members, and sealing the space between the first and second members with the resin composition by pressing the component assembly under heating simultaneously with or after obtaining the component assembly.

[0012] When the composite powder obtained by the manufacturing method of the present invention is mixed with a matrix resin to form a resin composition, the fluidity of the resin composition is improved compared to conventional resin compositions containing negative thermal expansion materials, and the increase in viscosity associated with the mixing of negative thermal expansion materials can be suppressed. Furthermore, the composite powder obtained by the manufacturing method of the present invention can suppress the increase in viscosity associated with an increase in the amount of negative thermal expansion material mixed. As a result, for example, yield can be improved in the manufacture of semiconductor devices. Moreover, according to the manufacturing method of the present invention, a composite powder having desired properties (preferably high circularity) can be obtained inexpensively and efficiently by firing at a lower temperature compared to conventional negative thermal expansion materials.

[0013] <Method for producing composite powder> The method for producing composite powder of the present invention comprises the following steps: (a) providing a powder of a compound comprising at least one selected from the group consisting of Zn, Mg, and P, wherein the compound is a negative thermal expansion material; (b) mixing an oxide of an element comprising at least one selected from the group consisting of an element belonging to group 5 or 6 of the periodic table, Li, and B, in an amount of 0.01 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the powder of the compound provided in step (a), to form a mixed powder; and (c) obtaining a composite powder by calcining the mixed powder formed in step (b).

[0014] Step (a) In step (a) of the method for producing a composite powder, as a means of providing a compound powder which is a negative thermal expansion material formed from a compound containing at least one element selected from the group consisting of Zn, Mg, and P (for simplicity, this element may be referred to as "element A" hereafter), a dry synthesis method such as calcination or gas-phase reaction synthesis, or a wet synthesis method such as liquid-phase synthesis (hydrothermal reaction) or coprecipitation synthesis can be appropriately selected and employed. A precursor may be synthesized by a wet synthesis method, and then the compound powder may be synthesized by a dry synthesis method. For powders of compounds other than oxides, in addition to the above synthesis methods, any known synthesis method may be appropriately selected and employed for their synthesis.

[0015] A dry synthesis method for obtaining a compound powder that is a negative thermal expansion material may include, for example, (i) preparing a raw material compound which is a single or multiple mixture containing at least one selected from the group consisting of Zn, Mg, and P; (ii) obtaining a primary calcined product by calcining the raw material compound; (iii) obtaining a secondary calcined product by crushing and remixing the primary calcined product and then calcining it again; (iv) optionally obtaining an additional calcined product by performing step (c) at least once more; (v) crushing the secondary calcined product or additional calcined product; (vi) optionally grinding the crushed secondary calcined product or additional calcined product; (vii) optionally sieving the ground secondary calcined product or additional calcined product with or without washing and decantation with water; and (viiii) optionally drying the sieved secondary calcined product or additional calcined product.

[0016] The starting compound containing at least one element selected from the group consisting of Zn, Mg, and P is not particularly limited as long as it is a compound containing the desired element. The starting compound may be at least one element selected from the group consisting of Zn, Mg, and P. An example of a starting compound containing at least one element selected from the group consisting of Zn, Mg, and P that is suitably used in the dry synthesis method is a compound containing the element and an oxygen atom, for example, P ２ O ５ Examples include one or more types such as ZnO and MgO. For example, an example of a P-containing compound used as a raw material is phosphorus pentoxide (P ２ O ５ In addition to ), phosphoric acid (H ３ PO ４ ), diammonium hydrogen phosphate ((NH ４ ) ２ HPO ４ ), ammonium dihydrogen phosphate (NH ４ H ２ PO ４ ), ammonium phosphate, pyrophosphate, polyphosphate, Zn ２ P ２ O ７ Mg ２ P２ O ７ Examples include one or more of the following.

[0017] The calcination temperature at each calcination stage in the dry synthesis method is not particularly limited, but may be, for example, 200°C or higher, 250°C or higher, or 300°C or higher, or 1200°C or lower, 1000°C or lower, or 900°C or lower. The calcination temperature range at each calcination stage in the dry synthesis method may be, for example, 200°C or higher and 1200°C or lower, or 250°C or higher and 1000°C or lower, or 300°C or higher and 900°C or lower. From the viewpoint of reliably obtaining compound powder having the desired composition, it is preferable to set the calcination temperature higher as the process progresses to the subsequent calcination stage. The number of times the calcination stage is repeated is usually two or three times, but it may be repeated four or more times if necessary.

[0018] The optional grinding of the secondary or additionally fired material after crushing may be dry or wet grinding. Dry grinding can be performed, for example, using a jet mill with a collision plate or a jet mill that causes particles to collide with each other. Wet grinding can be performed, for example, by adding a small amount of dispersant to the crushed and fired material as needed, and while stirring, supplying beads such as small-diameter zirconia beads to a media-stirring bead mill.

[0019] Optional sieving of the crushed calcined material is performed, for example, to obtain a preferred range of volume cumulative particle size D. ５０ An appropriate sieve can be selected to obtain a compound powder that is a negative thermal expansion material having the following properties. The average particle size of the compound powder obtained through sieving (i.e., the target of sieving) is determined by the cumulative particle size D at 50% cumulative volume measured by laser diffraction scattering particle size distribution analysis, from the viewpoint of the dispersibility of the mixed powder containing it into a matrix material such as resin, glass, or metal. ５０ It is preferable that the particle size is 0.05 μm or more and 100 μm or less. The volume cumulative particle size D of the compound powder obtained after sieving. ５０More preferably, the particle size may be 0.05 μm to 50 μm, 0.05 μm to 40 μm, 0.05 μm to 30 μm, 0.05 μm to 20 μm, or 0.05 μm to 10 μm. In another preferred embodiment, the volume cumulative particle size D of the compound powder obtained by sieving. ５０ The particle size may be 0.1 μm to 50 μm, 0.5 μm to 40 μm, 1 μm to 30 μm, 1.5 μm to 20 μm, or 2 μm to 10 μm. Washing with water and decantation, which may be performed in conjunction with sieving, are preferably repeated until the desired conductivity (e.g., 20 μS / cm or less) is achieved. Drying, which is optionally performed on the sieved calcined material, may be carried out, for example, at 50°C to 200°C, preferably 80°C to 150°C, for 30 minutes to 10 hours, preferably 1 hour to 8 hours.

[0020] A wet synthesis method for obtaining a compound powder that is a negative thermal expansion material may include, for example, (i) preparing a raw material compound which is a single or multiple mixture containing at least one selected from the group consisting of Zn, Mg, and P; (ii) obtaining a hydrothermally treated mixture by hydrothermally treating the raw material compound; (iii) optionally separating the solid and liquid of the hydrothermally treated mixture and washing it; (iv) drying the hydrothermally treated mixture; and (v) calcining the dried mixture.

[0021] The raw material compound containing at least one element selected from the group consisting of Zn, Mg, and P is not particularly limited as long as it is a compound containing the desired element. The raw material compound may be at least one element selected from the group consisting of Zn, Mg, and P. Examples of raw material compounds containing at least one element selected from the group consisting of Zn, Mg, and P that are suitably used in liquid-phase synthesis (hydrothermal reaction) include one or more of the following: chloride salts or hydrates thereof, oxychloride salts or hydrates thereof, acetates or hydrates thereof, oxyacetates or hydrates thereof, sulfates or hydrates thereof, nitrates or hydrates thereof, carbonates or hydrates thereof, ammonium carbonates or hydrates thereof, sodium carbonates or hydrates thereof, potassium carbonates or hydrates thereof, polyacids or salts or hydrates thereof, oxides or hydrates thereof, etc. The raw material compound may optionally contain sulfuric acid as a sulfur raw material. For example, an example of a P-containing compound used as a raw material compound is phosphoric acid (H ３ PO ４ ), diammonium hydrogen phosphate ((NH ４ ) ２ HPO ４ ), ammonium dihydrogen phosphate (NH ４ H ２ PO ４ Examples include one or more of the following: ammonium phosphate, pyrophosphate, polyphosphate, etc.

[0022] The hydrothermal treatment conditions for the raw material compounds in the liquid-phase synthesis method (hydrothermal reaction method) are not particularly limited, but for example, the reaction can be carried out continuously in a sealed container under pressure at a temperature of 100°C to 250°C, preferably 110°C to 230°C, for a period of time of, for example, 30 minutes to 100 hours, preferably 1 hour to 80 hours, 2 hours to 60 hours, or 3 hours to 40 hours.

[0023] In the liquid-phase synthesis method (hydrothermal reaction method), washing after solid-liquid separation may be performed, for example, by adding water to separate the solid-liquid again or by washing with water. This washing operation may be repeated multiple times.

[0024] In the liquid-phase synthesis method (hydrothermal reaction method), the drying of the hydrothermally treated mixture may be carried out, for example, at a temperature of 60°C to 200°C, preferably 50°C to 150°C, for about 30 minutes to 40 hours, preferably about 1 hour to 30 hours. Furthermore, the calcination of the dried mixture is not particularly limited, but may be at a temperature of 250°C or higher, 300°C or higher, or 350°C or higher, or 1200°C or lower, 1000°C or lower, or 900°C or lower.

[0025] The compound, which is a negative thermal expansion material formed in step (a), contains at least one element (element A) selected from the group consisting of Zn, Mg, and P, which may include any combination of these elements. That is, element A can be selected from Zn alone, Mg alone, P alone, a combination of Zn / Mg, a combination of Zn / P, a combination of Mg / P, or a combination of Zn / Mg / P.

[0026] The compound containing element A formed in step (a) may contain at least one selected from the group consisting of oxides, oxynitrides, nitrides, carbides, and sulfides of this element. The compound containing element A may be a mixture of two or more elements in any ratio selected from the group consisting of oxides, oxynitrides, nitrides, carbides, and sulfides of this element. From the viewpoint of thermal stability, such as not undergoing decomposition reactions when heated, oxides are preferred. The compositional analysis (atomic ratio) of the compound containing element A formed in step (a) can be performed using ICP-OES (Inductivity Coupled Plasma Optical Emission Spectrometry). The "Agilient 5110" (manufactured by Agilient Technologies) can be used as the ICP-OES instrument.

[0027] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), has a negative thermal expansion coefficient (negative thermal expansion coefficient) that exhibits the characteristic of decreasing in volume as the temperature rises. Such a negative thermal expansion material may have a temperature range in which the linear expansion coefficient (α: as defined below) is less than 0 ppm / K, preferably -10 ppm / K or less, more preferably -20 ppm / K or less, even more preferably -30 ppm / K or less, and even more preferably -40 ppm / K or less. By using a compound powder containing element A formed in step (a), which is a negative thermal expansion material, and exhibiting a low coefficient of linear expansion within an appropriate temperature range, when a resin composition containing the composite powder is used as a encapsulating resin for semiconductor devices, the expansion of the encapsulating resin can be reduced, thereby suppressing damage and malfunctions of semiconductor devices and improving yield. Hereafter, compound powders and composite powders that are negative thermal expansion materials may be referred to as "negative thermal expansion powders." By mixing two or more types of negative thermal expansion powders, a material capable of gradual thermal shrinkage with two or more shrinkage temperature ranges can be obtained. This makes it possible to suppress the rapid shrinkage of the negative thermal expansion material. Therefore, for example, a resin composition containing a mixture of two or more such negative thermal expansion materials can reduce the difference in thermal expansion with the resin in the shrinkage temperature range compared to a resin composition containing only one type of negative thermal expansion material.

[0028] In this specification, the "coefficient of linear expansion (α)" is defined by the following formula (1): Coefficient of linear expansion (α) [unit ppm / K] = (1 / L) × (ΔL / ΔT) × 10 ６... (1) In the formula, L refers to the length of the sample (μm), ΔL refers to the change in sample length (μm) within the specified temperature range, and ΔT refers to the temperature difference (K) within the specified temperature range. In this specification, the "dimensional change ratio," which is the ratio of the change in sample length within the specified temperature range, is defined by the following formula (2): Dimensional change ratio (dimensionless) = ΔL / L ... (2) ΔL and L in the formula are as defined above. The coefficient of linear expansion (α) is expressed in the following relationship with the dimensional change ratio ΔL / L: Coefficient of linear expansion (α) [ppm / K] = {(ΔL / L) / ΔT} × 10 ６

[0029] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), may have a temperature range in which the dimensional change ratio (ΔL / L) is less than 0 in any range within the temperature range of -200°C to 500°C, preferably in any range within the temperature range of 0°C to 200°C, and more preferably in a temperature range of room temperature or higher (for example, 0°C or higher, 10°C or higher, 20°C or higher, or 30°C or higher) to 150°C, preferably -2 × 10 －３ It may have a temperature range of the following, more preferably -3 × 10 －３ It may have a temperature range of the following, and more preferably -4 × 10 －３ The temperature range may be as follows, and more preferably -6 × 10 －３ The compound powder, which is a negative thermal expansion material containing element A, may have the following temperature range: In any range within the temperature range of -200°C to 500°C, preferably in any range within the temperature range of 0°C to 200°C, and more preferably in a temperature range of room temperature or higher (for example, 0°C or higher, 10°C or higher, 20°C or higher, or 30°C or higher) to 150°C, the dimensional change ratio (ΔL / L) is -8 × 10 －３ It may have a temperature range of the following, or -10 × 10 －３ The following temperature range may be included.

[0030] The dimensional change ratio (ΔL / L: the ratio of length change due to linear expansion) in this specification may be measured in the state of a compacted molded body (unsintered) of a negative thermal expansion material (powder), or by sintering this compacted molded body. The dimensional change ratio can be measured by a thermomechanical analyzer (TMA), for example, by a Hitachi High-Tech TA7000. When calculating the coefficient of linear expansion (α) using the above formula (1), when substituting the values ​​for L to ΔL as described above, the sample length in units of mm displayed on the above device should be set to 10 ３ You can convert it to the unit μm by multiplying by two.

[0031] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a compound powder with the general formula: Zn ２－ｘ T ｘ P ２－ｙ A ｙ O ７±δ The material may contain at least one powder of an oxide represented by (T is at least one element selected from Mg, Ca, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi; A is at least one element selected from Al, Si, V, Ge, and Sn, satisfying 0 ≤ x < 2 and 0 ≤ y ≤ 2; and δ is a value determined to satisfy the charge neutrality condition, excluding (x, y) = (0, 0) and (0, 2).). In this specification, the "charge neutrality condition" does not have to be completely neutral, and compositions with oxygen deficiencies or excesses within an acceptable range for the compound may be included.

[0032] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a material with the general formula: Cu ２－ｘ R ｘ V ２－ｙ P ｙ O ７±δThe material may contain at least one powder of an oxide represented by (R, which includes at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, and Sn, satisfying 0 ≤ x ≤ 2 and 0 < y < 2, and δ is a value determined to satisfy the charge neutrality condition).

[0033] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a solid solution of Al atoms with the general formula: Cu ｘ M ｙ V ｚ O ｔ±δ The product may contain at least one powder of an oxide represented by the formula (wherein M represents a metallic element with an atomic number of 11 or higher other than Cu, V, and Al, and is one or more metallic elements selected from Zn and Mn. x represents 1.60 ≤ x ≤ 2.40, y represents 0.00 ≤ y ≤ 0.40, z represents 1.70 ≤ z ≤ 2.30, t represents 6.00 ≤ t ≤ 9.00, and δ is a value determined to satisfy the charge neutrality condition, where 1.00 ≤ x + y ≤ 3.00. Also, when element M is included, the number of moles of Al atoms on an atomic basis > the number of moles of M atoms on an atomic basis.)

[0034] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a solid solution of Li atoms with the general formula: (Cu ｘ M ｙ ) (V ａ P ｂ ) O ｔ±δ The material may contain at least one powder of an oxide represented by the formula (wherein M represents a metallic element with an atomic number of 11 or higher other than Cu and V, preferably one or more selected from Zn, Ga, Fe, Mg, Co, Mn, Al, Ba, and Ca. x represents 1.60 ≤ x ≤ 2.40, y represents 0.00 ≤ y ≤ 0.40, a represents 1.60 ≤ a ≤ 2.40, b represents 0.00 ≤ b ≤ 0.40, t represents 5.00 ≤ t ≤ 9.00, and δ is a value determined to satisfy the charge neutrality condition, provided that 1.60 ≤ x + y ≤ 2.40 and 1.60 ≤ a + b ≤ 2.40).

[0035] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a material with the general formula: Zr ｘ (WO４ ) ｙ±δ１ (PO ４ ) ｚ±δ２ (In the formula, 1.7 ≤ x ≤ 2.3, 0.8 ≤ y ≤ 1.2, 1.7 ≤ z ≤ 2.3, and δ1 and δ2 are values determined independently to satisfy the charge neutrality condition.) It may contain at least one kind of powder of the oxide represented by

[0036] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a general formula: Zr ２．００－ｂ M ｂ S Ｙ P Ｚ O １２．００±δ (In the formula, M is at least one selected from Ti, Ce, Sn, Mn, Hf, Ir, Pb, Pd, Cr, W, Mo, 0 ≤ b < 2.00, 0 < Y < 0.30, Z ≥ 2.00, and δ is a value determined to satisfy the charge neutrality condition.) It may contain at least one kind of powder of the oxide represented by

[0037] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a general formula: Zr ２．００－ｂ M ｂ S Ｙ P Ｚ O １２．００±δ (In the formula, M is at least one selected from Ti, Ce, Sn, Mn, Hf, Ir, Pb, Pd, Cr, W, Mo, 0 ≤ b < 2.00, 0.30 ≤ Y ≤ 1.00, Z > 2.00, and δ is a value determined to satisfy the charge neutrality condition.) It may contain at least one kind of powder of the oxide represented by

[0038] The compound powder, which is a negative thermal expansion material containing element A formed in step (a), is, for example, a general formula: Ti ２－ｘ M ｘ O ３±δ (M contains at least one element selected from Mg and Zn, satisfies 0 < x < 2, and δ is a value determined to satisfy the charge neutrality condition.) It may contain at least one kind of powder of the oxide represented by

[0039] As described above, the average particle size of the compound powder, which is a negative thermal expansion material containing element A formed in step (a), is determined by the cumulative volume particle size D at 50% cumulative volume measured by laser diffraction scattering particle size distribution analysis, from the viewpoint of the dispersibility of the mixed powder containing it into a matrix material such as resin, glass, or metal. ５０ It is preferable that the volume cumulative particle size D of the compound powder which is a negative thermal expansion material. ５０ More preferably, the volume cumulative particle size D of the compound powder which is a negative thermal expansion material may be 0.05 μm to 50 μm, 0.05 μm to 40 μm, 0.05 μm to 30 μm, 0.05 μm to 20 μm, or 0.05 μm to 10 μm. In another preferred embodiment, the volume cumulative particle size D of the compound powder which is a negative thermal expansion material ５０ The particle size may be 0.1 μm to 50 μm, 0.5 μm to 40 μm, 1 μm to 30 μm, 1.5 μm to 20 μm, or 2 μm to 10 μm.

[0040] Step (b) The step (b) of forming a mixed powder in the method for producing a composite powder is to mix an oxide of an element containing at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, in an amount of 0.01 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the compound powder provided in step (a). The mixing ratio of the oxide of an element containing at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, to the compound powder provided in step (a) is preferably 0.03 to 30 parts by mass, 0.05 to 20 parts by mass, 0.1 to 30 parts by mass, 0.1 to 20 parts by mass, 0.1 to 20 parts by mass, 0.1 to 10 parts by mass, 0.1 to 10 parts by mass, 0.2 to 20 parts by mass, 0.2 to 10 parts by mass, 0.2 to 5 parts by mass, 0.3 to 10 parts by mass, 0.3 to 3 parts by mass, 0.4 to 5 parts by mass, or 0.4 to 3 parts by mass per 100 parts by mass of the compound powder. By mixing the compound powder provided in step (a) with an oxide of an element containing at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, in the above ratio, a composite powder can be obtained by firing at a lower temperature (i.e., firing at a lower energy cost) compared to when using conventional negative thermal expansion material powders. Preferably, because firing at a lower temperature is possible, the resulting composite powder may have high crystallinity and high circularity. The composite powder thus obtained, having high crystallinity and high circularity, has excellent negative thermal expansion properties and, when used in a resin composition, exhibits excellent fluidity and viscosity.

[0041] The oxide of an element used in step (b), which includes at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, is not particularly limited as long as it is an oxide of an element that includes at least one element selected from the above group. That is, the oxide of an element used in step (b), which includes at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, may be an oxide of V alone, Nb alone, Ta alone, Db alone, Cr alone, Mo alone, W alone, Sg alone, Li alone, or B alone, or it may be a composite oxide containing two or more elements. An example of such an oxide is molybdenum trioxide (MoO ３ ), lithium molybdate (Li ２ MoO ４ ), vanadium pentoxide (V ２ O ５ ), lithium tetraborate (Li ２ B ４ O ７ ) are some examples.

[0042] In one embodiment of the present invention, the oxide of an element used in step (b), which includes at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, preferably includes at least one oxide selected from the group consisting of V, Nb, Ta, Cr, Mo, and W belonging to group 5 or 6 of the periodic table. Furthermore, in one embodiment of the present invention, the oxide of an element used in step (b), which includes at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, preferably includes at least one oxide selected from the group consisting of V and Mo belonging to group 5 or 6 of the periodic table. These oxides can be mixed with the compound powder provided in step (a) and fired to lower the firing temperature, thereby increasing the circularity and crystallinity of the composite powder.

[0043] In one embodiment of the present invention, from the viewpoint of further lowering the calcination temperature of the composite powder, it is preferable that the oxide of an element used in step (b), which includes at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, includes an oxide having a melting point of 650°C or higher and 950°C or lower.

[0044] In one embodiment of the present invention, the oxide of an element used in step (b), which includes at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, preferably includes an oxide in powder or liquid form. Here, the liquid form may include a solution obtained by dissolving the oxide in a solvent. The solvent may be water.

[0045] If the oxide of an element used in step (b) is a powder containing at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, then from the viewpoint of mixing and firing it with the compound powder which is a negative thermal expansion material containing element A provided in step (a), and from the viewpoint of the dispersibility of the resulting composite powder in a matrix material such as resin, glass, or metal, this oxide powder typically has a volume cumulative particle size D at 50% of the cumulative volume measured by laser diffraction scattering particle size distribution analysis. ５０ It is preferable that the particle size is 0.01 μm or more and 20 μm or less. The volume cumulative particle size D of the oxide powder of an element used in step (b), which includes at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B. ５０ More preferably, the volume cumulative particle size D of the oxide powder of an element used in step (b), which includes at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li and B. ５０The particle size may be 0.02 μm or more and 15 μm or less, 0.03 μm or more and 12 μm or less, 0.04 μm or more and 10 μm or less, 0.05 μm or more and 9 μm or less, 0.06 μm or more and 8 μm or less, 0.07 μm or more and 7 μm or less, or 0.07 μm or more and 3 μm or less.

[0046] The method for mixing the compound powder provided in step (a) with an oxide of an element containing at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, in step (b) is not particularly limited. As a mixing method, mixing by manual or mechanical means can usually be employed at around room temperature (e.g., 0°C to 50°C, preferably 10°C to 40°C, or 15°C to 35°C) without excessive heating or cooling. Manual mixing can be performed, for example, in a mortar and pestle. For mechanical mixing, for example, grinders such as ball mills and vibratory mills, and mixers such as screw mixers and Henschl mixers can be used. The mixing time can be appropriately set depending on the processing scale and the specifications of the mixing equipment, etc., so that a more uniform mixed powder is formed. The mixing time may be, for example, 30 seconds to 1 hour, 1 minute to 40 minutes, or 2 minutes to 20 minutes.

[0047] If the oxide of an element used in step (b), which includes at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, is supplied in liquid form, the oxide can be dissolved in a solvent to form a solution. In this case, the mixing in step (b) may be carried out by adding the compound powder provided in step (a) to the oxide solution and stirring. The concentration of the oxide solution can be adjusted as appropriate so that the mixing ratio of the compound provided in step (a) and the oxide falls within the range described above.

[0048] Step (c) Step (c) in the method for producing a composite powder is to calcine the mixed powder formed in step (b) to form a composite powder. While the calcination temperature of conventional negative thermal expansion materials is generally 1000°C or higher (for example, temperatures in the range of 1000°C to 1200°C), the calcination temperature in step (c) can be lower than the calcination temperature of conventional negative thermal expansion materials (at a lower energy cost). The calcination temperature of the mixed powder in step (c) may be, for example, 250°C to 1000°C, preferably 300°C to 900°C, 350°C to 800°C, or 400°C to 700°C. The calcination time may be, for example, usually 10 minutes to 12 hours, preferably 20 minutes to 10 hours, 30 minutes to 9 hours, 40 minutes to 8 hours, 50 minutes to 7 hours, or 1 hour to 6 hours. The compounded mixed powder may be compounded as uniform core-shell particles, or it may be compounded in a non-uniform coating state.

[0049] The calcined product obtained in step (c) may be subjected to the same steps as described above for the dry synthesis method for obtaining compound powders that are negative thermal expansion materials: (v) crushing, (vi) optional grinding, (vii) optional sieving, and (viiii) optional drying.

[0050] <Composite Powder> Another aspect of the present invention relates to a composite powder which is a substance produced by any of the embodiments described above relating to the manufacturing method of the present invention. The composite powder obtained by the above method is a composite powder formed from (i) a compound comprising at least one selected from the group consisting of Zn, Mg and P, and (ii) an oxide of an element comprising at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li and B.

[0051] The composite powder obtained by the method described above is presumed to be a powder consisting of particles in which (i) oxide particles containing at least one element selected from the group consisting of Zn, Mg, and P are present at least on and near the surface, and (ii) at least one element selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B are present in small amounts. For this reason, the composite powder can have a high degree of circularity without impairing the negative thermal expansion properties, and when used as a resin composition, the resin composition has high fluidity and viscosity.

[0052] (i) The oxide comprising at least one selected from the group consisting of Zn, Mg, and P is preferably an oxide comprising Zn, Mg, and P, and more preferably an oxide comprising Zn, Mg, P, and O.

[0053] An example of such an oxide is Zn ２－ｘ Mg ｘ P ２ O ７ An example of an oxide is represented by the formula shown. Here, x may be 0.1 or more and 0.8, preferably 0.2 or more and 0.5 or less. Such oxide particles can be used to obtain excellent negative thermal expansion properties, and can also be easily fired to obtain a dense and stable powder.

[0054] Furthermore, the presence of element (ii) in the composite powder in small amounts may mean that it is present at a concentration of 100 ppm or less relative to the mass of oxide (i). During the calcination step to obtain the composite powder by the method described above, most of the oxides of elements including at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, melt, vaporize, or sublimate, while some may remain on and near the surface of oxide (i). On the other hand, calcining until oxides of elements including at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B are no longer detectable is not practical from the standpoint of temperature and the number of calcinations.

[0055] One method to confirm that element (ii) is present in the composite powder obtained by the above method at a concentration of 100 ppm or less relative to the mass of oxide (i) is to combine ICP-OES and XPS. Specifically, by using ICP-OES (sensitivity 100 ppm), the absence of a peak indicates that element (ii) is present at a concentration of 100 ppm or less. On the other hand, XPS indicates that element (ii) is present on the surface of the particles in the composite powder.

[0056] In one embodiment, the circularity of the composite powder obtained by the above method may be 0.75 or more and 1.00 or less. Preferably, the circularity of the composite powder may be 0.77 or more and 1.00 or less, more preferably 0.79 or more and 1.00 or less, and even more preferably 0.81 or more and 1.00 or less. The closer the circularity is to 1.00, the closer the particle shape is to a perfect sphere.

[0057] In this specification, the circularity (sphericity) of a composite powder can be measured as follows: A sample of the composite powder is observed at a magnification of 2500x using a scanning electron microscope (SU3500, Hitachi High-Technologies Corporation) to obtain three SEM images. For each of the three obtained SEM images, image adjustment is performed by binarizing the particles and background. Then, image analysis is performed on each of the 100 particles in the image. Using the image processing software ImageJ, drawing is performed along the particles, and after all drawing is completed, particle analysis is performed to obtain the average area and average circumference of one particle. Then, the circularity for one SEM image is calculated using equation (3). The arithmetic mean of the sphericity obtained from the three images is taken as the circularity (sphericity). Circularity of one particle = 4π × (average area of ​​one particle) / (average circumference of one particle) ２... (3) Although the concept of circularity or sphericity of composite powders (particles), and the fact that the closer the value is to 1, the higher the degree of spherical approximation of the particle shape, have been known for some time, it is not known, and is considered not to be an easy task, to raise the sphericity of composite powders to 0.7 or higher using the calculation method defined above, which is unique to this application. The terms "circularity" or "sphericity" used here can also be rephrased as "sphericity."

[0058] The average particle size of the composite powder obtained by the above method is determined by the cumulative particle size D at 50% cumulative volume, as measured by laser diffraction scattering particle size distribution analysis, from the viewpoint of dispersibility in matrix materials such as resin, glass, and metal. ５０ It is preferable that the particle size is between 0.05 μm and 50 μm. Volume cumulative particle size D of the composite powder ５０ More preferably, the thickness may be 0.1 μm to 30 μm, 0.5 μm to 20 μm, 1.0 μm to 15 μm, or 1.5 μm to 10 μm.

[0059] The BET specific surface area of ​​the composite powder obtained by the above method is 0.1 m². ２ / g or more 10m ２ It is preferable that the BET specific surface area is less than or equal to / g. Having the BET specific surface area within this range can suppress the increase in viscosity of the matrix material such as resin, glass, or metal in the mixed powder, thereby improving packing performance. The BET specific surface area of ​​the mixed powder is more preferably 0.1 m². ２ / g or more 9m ２ It may be less than or equal to / g, and more preferably 0.3m ２ / g or more 8m ２ / g or less, 0.5m ２ / g or more 7m ２ / g or less, 0.7m ２ / g or more 6m ２ / g or less, 0.9m ２ / g or more 5m ２ / g or less, or 1m ２ / g or more 4m ２ It may be less than or equal to / g.

[0060] The volume resistivity of the composite powder obtained by the above method is 1.0 × 10⁻⁶ at 25°C, which is suitable for use in applications requiring insulating properties. ９ It is preferable that the resistivity is Ω·cm or greater. The volume resistivity of the composite powder is more preferably 5.0 × 10 at 25°C. ９ Ω・cm or more, 1.0×10 １０ Ω・cm or more, 5.0×10 １０ Ω・cm or more, 1.0×10 １１ Ω・cm or more, 5.0×10 １１ Ω·cm or greater, or 1.0 × 10⁻⁶ １２ It may be Ω·cm or greater. In this specification, the volume resistivity of a composite powder can be measured, for example, by compressing the composite powder at a pressure of 63 MPa using the powder resistance measurement system "MCP-PD51" manufactured by Nitto Seiko Analytech Co., Ltd., and following the four-terminal method. Samples that exceed the measurement limit of this device can be measured by separately preparing pellets compressed at a pressure of 63 MPa and measuring them using the high-resistivity meter Hi-Resta UX / MCP-HT800 manufactured by Nitto Seiko Analytech Co., Ltd.

[0061] In one embodiment, the composite powder obtained by the above-described method has a uranium (U) and thorium (Th) content of 1 ppm by mass or less, and a lead (Pb) and bismuth (Bi) content of 30 ppm by mass or less. By having these component content levels within the above range, the generation of alpha rays, as described later, can be suppressed.

[0062] The composite powder obtained by the above method may be provided in a form other than powder. That is, in addition to powder, the composite powder may be provided in the form of a compacted powder body, or in various shapes such as a film material or a plate material.

[0063] <Resin Composition> In yet another embodiment of the present invention, a method for producing a resin composition is provided, comprising combining the composite powder and resin components. The composite powder used to obtain the resin composition may be any of the embodiments described above. The type and amount of resin components used in the resin composition are not particularly limited and can be appropriately selected and adjusted to obtain the target negative thermal expansion properties or other desired properties. The term "resin composition" as used herein is intended to encompass both a composition that partially contains a solvent such as water or an organic solvent used when mixing the components to prepare the resin composition, and a composition in which such a solvent has been removed under reduced pressure after the preparation of the resin composition.

[0064] Examples of resin components, though not particularly limited, include epoxy resins; polyolefin resins such as polyethylene resins and polypropylene resins; polyvinyl resins such as polyvinyl chloride resins and polyvinyl butyral resins; phenolic resins such as polyphenylene sulfide resins and polystyrene resins such as ABS; polyacrylate resins; polyamide resins; polyimide resins; polyamide-imide resins; polyetherimide resins; silicone resins; polycarbonate resins; ester resins or unsaturated polyester resins such as polybutylene terephthalate (PBT resin) and polyethylene terephthalate (PET resin); fluororesins; liquid crystal polymers; polysulfones; polyethersulfones; aromatic polyether ketone resins such as polyetherether ketones; and mixtures of two or more of these. Among these resins, epoxy resins are preferred from the viewpoint of balancing various properties such as rapid curing, mechanical properties, and heat resistance.

[0065] The amount of resin components constituting the resin composition is not particularly limited, but is usually 5% by mass or more and 95% by mass or less, preferably 10% by mass or more and 80% by mass or less, more preferably 15% by mass or more and 75% by mass or less, and even more preferably 20% by mass or more and 70% by mass or less, relative to the total amount of the resin composition.

[0066] In addition to the composite powder and resin components, the resin composition may contain at least one inorganic material powder, such as silica (silicon dioxide), silicates, titanium dioxide, graphite, sapphire (aluminum oxide), magnesium oxide, calcium oxide, silicon nitride, boron nitride, aluminum nitride, various glass materials, concrete materials, and various ceramic materials. The inorganic material powder may be in the form of crushed material, spherical material, or aggregates such as fumed silica. The inorganic material powder is preferably spherical in order to reduce the viscosity of the resin composition. For example, if the inorganic material powder is silica, it may be crystalline or amorphous. The total amount of composite powder and inorganic material such as silica (if present) in the resin composition is not particularly limited, but is usually 5% to 95% by mass, preferably 10% to 80% by mass, more preferably 15% to 75% by mass, and even more preferably 20% to 70% by mass, relative to the total amount of the resin composition.

[0067] In one embodiment, the resin composition may be obtained by further combining a curing agent with the composite powder and resin components. Any known curing agent may be used, such as acid anhydride compounds, phenolic compounds, amine / amide compounds, and active ester compounds. The amount of curing agent included in the resin composition is not particularly limited, but is usually 0.05% to 10% by mass, preferably 0.1% to 5% by mass, and more preferably 0.5% to 3% by mass, relative to the total amount of the resin composition.

[0068] Examples of acid anhydride compounds that may be included in the resin composition as curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, polypropylene glycol maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Examples of phenolic compounds that may be included in the resin composition as curing agents include dicyclopentadienephenol addition resins, phenol aralkyl resins, naphthol aralkyl resins, triphenylol methane resins, tetraphenylolethane resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, biphenyl-modified phenolic resins, aminotriazine-modified phenolic resins, and modified products thereof.

[0069] Examples of amine / amide compounds that may be included in the resin composition as curing agents include aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, polypropylene glycol diamine, diethylenetriamine, triethylenetetramine, and pentaethylenehexamine; aromatic polyamines such as metaxylylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and phenylenediamine; alicyclic polyamines such as 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, and norbornanediamine; and polyamide resins synthesized from dicyandiamide, a dimer of linolenic acid, and ethylenediamine. Examples of active ester compounds that may be included in the resin composition include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Preferred examples of active ester compounds include those obtained by the condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound (or its halide) with a hydroxy compound and / or a thiol compound. More preferred examples of active ester compounds include those obtained from a carboxylic acid compound or its halide with a phenol compound and / or a naphthol compound. Examples of carboxylic acid compounds that constitute such active ester compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc., or their halides.Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, dihydroxydiphenyl ether, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, polyhydroxynaphthylene ether, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, and dicyclopentadiene-phenol addition resins.

[0070] The resin composition may further contain other additives. Examples of other additives that may be included in the resin composition include inorganic fillers and fibers other than compounds that are negative thermal expansion materials containing at least one element selected from the group consisting of Zn, Mg, and P; lubricants and mold release agents such as fatty acid amides, fatty acid esters, and metal salts of fatty acids; ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds, and phenyl salicylate compounds; hindered amine stabilizers; phenolic and phosphorus-based antioxidants; tin-based heat stabilizers; various antistatic agents; lubricity improvers such as polysiloxanes; various coloring pigments; silane coupling agents; titanium coupling agents; colorants such as dyes; plasticizers such as waxes and silicone resins; metal oxides other than compounds that are negative thermal expansion materials containing at least one element selected from the group consisting of Zn, Mg, and P; composite oxides of multiple metals other than compounds that are negative thermal expansion materials containing at least one element selected from the group consisting of Zn, Mg, and P; and mixtures of two or more of these. The amount of such other additives in the resin composition is not particularly limited, but from the viewpoint of maintaining the negative thermal expansion properties and other properties of the resin composition, it may be 5% by mass or less, preferably 3% by mass or less, relative to the total amount of the resin composition.

[0071] The alpha dose of the composite powder and resin composition was 0.0200 cph / cm². ２The following is preferable: When the alpha dose of the composite powder and resin composition is within this range, malfunctions caused by current noise generated by alpha rays can be suppressed when the composite powder and resin composition are used as encapsulating materials for semiconductor devices. The alpha dose of the composite powder and resin composition is more preferably 0.0150 cph / cm². ２ Further more preferably, 0.0100 cph / cm² ２ The following may apply: The alpha dose of the composite powder and resin composition is 0.050 cph / cm². ２ It may also be less than 0.020 cph / cm². ２ It may also be less than 0.010 cph / cm². ２ The following is also acceptable.

[0072] In this specification, for measuring the alpha dose, a semiconductor-type trace alpha-ray energy distribution analyzer may be used, or a measurement method using a gas prosthenal counter type analyzer or an ionization type analyzer based on the international standard JEDEC STANDARD may be used. When using a semiconductor-type trace alpha-ray energy distribution analyzer, for example, the Hitachi KS-1000 may be used. When using a semiconductor-type trace alpha-ray energy distribution analyzer, alcohol treatment may be performed as a pretreatment. As a more specific measurement method when measuring the alpha dose of a powder sample using a semiconductor-type trace alpha-ray energy distribution analyzer, the following procedure may be adopted: (i) Place the sample to be measured (10 g) and ethyl alcohol (25 ml) into a 50 ml beaker and diffuse the beaker in an ultrasonic cleaner for about 1 minute. (ii) Transfer the entire amount of sample in the beaker to the sample stage so that the surface is uniform, and allow to air dry for about 2 hours. (iii) After natural drying, place the sample stage in a vacuum desiccator, start the vacuum pump, and perform vacuum drying for approximately 3 hours or more. (iv) The vacuum-dried sample stage will be used as the sample for trace alpha radiation measurement. (v) Set the sample stage in the chamber of the measuring device and perform measurement for 200 hours. The effective measurement area is 169 cm². ２The sample size shall be (13 cm x 13 cm). When measuring the alpha dose of a resin composition, the resin composition can be placed directly on the sample stage. The alpha dose shall be the net count value obtained by subtracting the background from the actual measurement result obtained by the above procedure. The surface alpha dose measured in the range of 2.0 to 10 MeV using the above-mentioned Hitachi KS-1000 device may be used as the alpha dose here.

[0073] In measuring alpha dose according to the international standard JEDEC STANDARD, the measurement can be performed by the following procedure: (i) Use a gas flow type alpha dose measuring device. As the sample to be measured, spread powder on a sample base, for example, with a surface area of ​​900 cm². ２ A sample sheet formed into a sheet shape is used. Depending on the device, the sample sheet may be one that fills the maximum measurement area. The sample sheet is placed as a measurement sample in the alpha dose measuring device (gas prosional counter type measuring device or ionization type measuring device), and PR gas is purged into it. The PR gas used conforms to the international standard JEDEC STANDARD. That is, the PR gas used for measurement is a mixture of 90% argon and 10% methane that has been filled into a gas cylinder for more than three weeks, and is a decayed radon (Rn) gas. (ii) After the PR gas is flowed through the alpha dose measuring device in which the sample sheet is placed for 12 hours and left to stand, the alpha dose measurement is performed for 72 hours. (iii) The average alpha dose is measured in "cph / cm²". ２ The alpha radiation dose is calculated as follows: Anomalies (such as counts due to device vibration) are removed from the count for that hour. The following devices are used for the above measurement method: ・Alpha-ray counter: For example, "LACS-4000M" manufactured by Sumika Analysis Center Co., Ltd. ・"Gas flow type alpha-ray measuring device (MODEL-1950)" manufactured by Alpha Science Co., Ltd. ・"Gas Flow Proportional Counter Model 8600A-LB" manufactured by Ordela Co., Ltd. ・"UltraLo-1800" manufactured by XIA Co., Ltd. The alpha radiation dose using this method is measured over a measurement area of ​​1000 cm². ２ From 4000cm ２This refers to the alpha dose value calculated from the values ​​counted over 72 to 100 hours.

[0074] <Powder Mixture> In yet another embodiment of the present invention, a method for producing a powder mixture is provided, comprising combining the composite powder with silica powder or other thermally conductive powder. The composite powder used to obtain the powder mixture may be any of the embodiments described above.

[0075] The silica powder that can constitute the powder mixture is not particularly limited as long as it is a particulate material containing silica. The silica powder may be silica. As silica, fused silica or crystalline silica may be used. The silica powder may be, for example, a core-shell type silica powder in which a silica layer is formed around core particles of resin particles or metal particles, or a hollow silica powder.

[0076] Other thermally conductive powders besides silica powder are not particularly limited and may be any known ones. Examples of other thermally conductive powders include carbon compounds such as graphite and diamond; metal oxides (other than Ca-containing composite oxides) such as aluminum oxide, magnesium oxide, beryllium oxide, titanium oxide, zirconium oxide, and zinc oxide; metal nitrides such as boron nitride, aluminum nitride, and silicon nitride; metal carbides such as boron carbide, aluminum carbide, and silicon carbide; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; metal carbonates such as magnesium carbonate and calcium carbonate; organic polymer calcined products such as acrylonitrile polymer calcined products, furan resin calcined products, cresol resin calcined products, polyvinyl chloride calcined products, sugar calcined products, and charcoal calcined products; composite ferrites of ferrite and Zn ferrite; Fe-Al-Si ternary alloys; metal powders, or mixtures thereof.

[0077] The particle shape of silica powder or other thermally conductive powders is preferably substantially spherical from the viewpoint of fluidity when mixed with a matrix material such as a resin. The cumulative volume particle size D at 50% cumulative volume, as measured by laser diffraction scattering particle size distribution analysis of silica powder or other thermally conductive powders. ５０From the same viewpoint as above, the particle size may be, for example, 0.1 μm or more and 10 μm or less, and preferably 0.5 μm or more and 5 μm or less.

[0078] The mass ratio of the composite powder to the silica powder or other thermally conductive powder in the powder mixture may be, for example, between 1:99 and 100:0, between 20:80 and 100:0, preferably between 30:70 and 95:5, more preferably between 40:60 and 90:10, even more preferably between 50:50 and 80:20, and even more preferably between 60:40 and 80:20, from the viewpoint of balancing the effective expression of the negative thermal expansion characteristics of the composite powder constituting the mixed powder with the suppression of manufacturing costs.

[0079] Alternatively, a powder mixture may be prepared by mixing two or more negative thermal expansion materials, and further containing silica-containing powder or other thermally conductive powder.

[0080] <Method for Manufacturing Electronic Components> For example, an electronic component can be manufactured by (1) applying a resin composition containing a composite powder and a resin component to a first member, (2) applying a second member to the resin composition simultaneously with or after the application of the resin composition to the first member to obtain a component assembly in which the resin composition is sealed between the first and second members, and (3) sealing the space between the first and second members with the resin composition by pressing the component assembly under heat simultaneously with or after obtaining the component assembly. In the manufacture of such an electronic component, a sealing material containing a resin composition containing a composite powder and a resin component can be applied for sealing the electronic component. Furthermore, in the manufacture of such an electronic component, a sealing material containing a resin composition containing a composite powder and a resin component can be applied as an underfill for sealing electronic components. That is, in this application, a sealing material for electronic components containing (or formed from) a resin composition containing a composite powder and a resin component is provided; and an underfill for sealing electronic components containing (or formed from) a resin composition containing a composite powder and a resin component is also provided. Underfill for electronic component encapsulation can be rephrased as underfill encapsulating material for electronic components.

[0081] As the resin composition applied to the first member, either the composite powder or the resin composition containing the resin component can be appropriately selected. Furthermore, the composite powder used to obtain the resin composition here may be any of the embodiments described above. The first member and the second member are not particularly limited, as long as the resin composition can be applied to their surface and they can withstand pressure bonding under heat. The materials constituting the first member and the second member may be the same or different. Specific examples of the first member and the second member include silicon wafers, metal plates, glass plates, heat-resistant resin plates, and electronic components such as semiconductor chips. For example, it is conceivable that one of the first member and the second member is a silicon wafer on which electrodes are mounted as a circuit board, and the other is a semiconductor chip on which electrodes are mounted.

[0082] In a preferred embodiment, a resin composition containing the composite powder and resin component is applied as an underfill encapsulant to a circuit board, which is a silicon wafer, a first component. A semiconductor chip, which is a second component, is placed on top of the resin composition, which is the underfill encapsulant. Then, by pressing under heat, the resin composition is cured and the electrodes formed on the semiconductor chip and the electrodes formed on the circuit board are connected simultaneously, thereby sealing the connection between the semiconductor chip and the circuit board components with the resin composition, and thus an electronic component (semiconductor device) can be manufactured. The heating temperature for pressing under heat is not particularly limited as long as the molten state of the resin constituting the resin composition is maintained. The pressure applied for pressing under heat is not particularly limited as long as the connection between the semiconductor chip and the circuit board can be reliably achieved. Such a thermocompression bonding method is called the NCP (Non-Conductive Paste) method. Advantages of the NCP method include the ability to shorten the process and curing time, and consequently, the possibility of providing a pre-supplied flip-chip bonding process that can be manufactured at low cost and with low energy. Furthermore, this heat-sealing method suppresses the generation of unfilled areas (voids) in the encapsulant and allows for a sufficient filling rate, even when the sphericity (perfect sphereness) of the mixed powder contained in the resin composition is not high.

[0083] In another preferred embodiment, a film-like semiconductor encapsulant, pre-formed from a resin composition containing the composite powder and resin component, is laminated onto a semiconductor chip, which is a first component. The film-like semiconductor encapsulant is then pressed against a circuit board, which is a second component, under heating to connect electrodes formed on the semiconductor chip and electrodes formed on the circuit board. Subsequently, the resin composition is heat-cured to manufacture an electronic component (semiconductor device) in which the semiconductor chip is mounted on the circuit board. Similar to the embodiments described above, the heating temperature for pressing under heating is not particularly limited as long as the molten state of the resin constituting the resin composition is maintained. The pressure applied for pressing under heating is not particularly limited as long as a reliable connection between the semiconductor chip and the circuit board can be achieved. Such a thermocompression bonding method is called the NCF (Non-Conductive Film) method. Advantageous of the NCF method is that even when the gap between the semiconductor chip and the substrate is narrow, good bonding performance can be achieved through reliable sealing with suppressed void generation. Furthermore, this thermocompression bonding method, similar to the NCP method, can suppress the generation of unfilled areas (voids) in the encapsulant and achieve a sufficient filling rate, even when the sphericity (perfect sphereness) of the mixed powder contained in the resin composition is not high.

[0084] In other preferred embodiments, instead of the NCP method or NCF method described above, electronic components (semiconductor devices) can be manufactured by the ACP (Anisotropic Conductive Paste) method or ACF (Anisotropic Conductive Film) method, which involves mixing predetermined conductive particles with a resin composition containing the composite powder and resin components to form an anisotropic conductive adhesive and performing a similar process. The conductive particles are not particularly limited, but examples include metal particles (e.g., nickel or nickel-gold coated composite materials), resin particles such as acrylic resin that are metal-plated (e.g., gold-plated), or particles having an insulating film that breaks or melts upon contact with heat or pressure. The average size of the conductive particles may be, for example, 1 μm to 50 μm. This thermocompression bonding method, like the NCP or NCF methods, can suppress the generation of unfilled areas (voids) in the encapsulant and achieve a sufficient filling rate, even when the sphericity (perfect sphereness) of the mixed powder contained in the resin composition is not high.

[0085] The present invention will be described in more detail below with reference to examples. These examples should be understood as merely illustrative and not as limiting the present invention in any way.

[0086] (1) Preparation of compound powder containing at least one selected from the group consisting of Zn, Mg, and P Preparation of compound powder (1-1) By dry synthesis method, Zn １．６ Mg ０．４ P ２ O ７ A ceramic sintered body was fabricated in the form of a compound powder of a negative thermal expansion material represented by . Specifically, zinc pyrophosphate (Zn) was prepared by weighing Zn and Mg in stoichiometric ratios. ２ P ２ O ７ 3H ２ O) and magnesium pyrophosphate (Mg ２ P ２ O ７The mixture was stirred in a bag for 60 seconds until no more aggregates formed. Next, the mixed powder was pressed into pellets and fired in an electric furnace at 350°C in air for 5 hours. Then, the resulting fired product was crushed in a mortar and remixed to obtain compound powder (1-1).

[0087] Preparation of compound powder (1-2) By dry synthesis method, Zn １．６ Mg ０．４ P ２ O ７ A ceramic sintered body was fabricated in the form of a compound powder of a negative thermal expansion material represented by . Specifically, MgO, ZnO, and ammonium dihydrogen phosphate (NH₄) were weighed in stoichiometric ratios of Zn and Mg. ４ H ２ PO ４ The mixture was stirred and mixed in a bag for 60 seconds until no more aggregates formed. Next, the mixed powder was pressed into pellets and subjected to primary calcination in an electric furnace at 250°C in air for 5 hours. Then, the resulting calcined material was crushed in a mortar and remixed, and further subjected to secondary calcination in an electric furnace at 350°C in air for 5 hours. This calcined material was crushed in a force mill for approximately 30 seconds to obtain compound powder (1-2).

[0088] Example 1: 100 parts by weight of compound powder (1-1) and molybdenum trioxide (MoO ３One part by weight of molybdenum trioxide (manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 700°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder. The X-ray diffraction patterns of compound powders were evaluated using powder X-ray diffraction (XRD) (measurement temperature 295 K, characteristic X-rays of CuKα: wavelength λ = 0.15418 nm) and synchrotron radiation temperature-dependent X-ray diffraction (wavelength λ = 0.06521 nm), and Zn １．６ Mg ０．４ P ２ O ７ We confirmed that the crystal structure was formed.

[0089] Example 2 100 parts by weight of compound powder (1-1) Lithium molybdate (Li ２ MoO ４ One part by weight of lithium molybdenate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 700°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0090] Example 3: 100 parts by weight of compound powder (1-1) and vanadium pentoxide (V ２ O ５ One part by weight of (FFF-J, manufactured by Shinko Chemical Industry Co., Ltd.) was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 700°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0091] Example 4 100 parts by weight of compound powder (1-1) Lithium tetraborate (Li ２ B ４ O ７ One part by weight of lithium tetraborate type II (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0092] Example 5 100 parts by weight of compound powder (1-1) Lithium molybdate (Li ２ MoO ４Three parts by weight of lithium molybdenate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 700°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at approximately 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0093] Example 6 100 parts by weight of compound powder (1-1) Lithium molybdate (Li ２ MoO ４ Three parts by weight of lithium molybdenate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0094] Example 7 100 parts by weight of compound powder (1-1) Lithium molybdate (Li ２ MoO ４Five parts by weight of lithium molybdenate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 700°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0095] Example 8 100 parts by weight of compound powder (1-1) Lithium molybdate (Li ２ MoO ４ Five parts by weight of lithium molybdenate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0096] Example 9 100 parts by weight of compound powder (1-2) and molybdenum trioxide (MoO ３One part by weight of molybdenum trioxide (manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0097] Example 10 100 parts by weight of compound powder (1-2) and molybdenum trioxide (MoO ３ 25 parts by weight of molybdenum trioxide (manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) were added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0098] Example 11 100 parts by weight of compound powder (1-2) and molybdenum trioxide (MoO ３50 parts by weight of molybdenum trioxide (manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) were added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0099] Example 12 100 parts by weight of compound powder (1-1) and molybdenum oxide precursor (manufactured by Mitsui Mining & Smelting Co., Ltd., product name: iconos®), molybdenum trioxide (MoO ３ ) Converted content: 10% by mass) 1 part by weight was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Next, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0100] Example 13: 100 parts by weight of compound powder (1-1), molybdenum oxide precursor (manufactured by Mitsui Mining & Smelting Co., Ltd., product name: iconos®), molybdenum trioxide (MoO ３) Converted content: 33% by mass) 1 part by weight was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Next, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0101] Example 14 100 parts by weight of compound powder (1-1) Lithium molybdate (Li ２ MoO ４ ) Solution (manufactured by Mitsui Mining & Smelting Co., Ltd., product name: iconos®, Li ２ MoO ４ 1 part by weight of (converted content: 5% by mass) was added and mixed in a mortar in air. The resulting mixed powder was calcined in an electric furnace at 700°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0102] Comparative Example 1 Compound powder (1-1) was calcined in an electric furnace at 700°C for 10 hours. The calcined material was then crushed for approximately 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at approximately 110°C for 3 hours, and then crushed for approximately 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0103] Comparative Example 2: 100 parts by weight of compound powder (1-1) and calcium carbonate (CaCO3) ３ One part by weight of calcium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and mixed in a mortar in the open air. The resulting mixed powder was calcined in an electric furnace at 700°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0104] Comparative Example 3 Compound powder (1-1) was calcined in an electric furnace at 800°C for 10 hours. The calcined material was then crushed for approximately 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at approximately 110°C for 3 hours, and then crushed for approximately 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0105] Comparative Example 4: 100 parts by weight of compound powder (1-1) and calcium carbonate (CaCO3) ３ One part by weight of calcium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and mixed in a mortar in the atmosphere. The resulting mixed powder was calcined in an electric furnace at 800°C for 10 hours. Next, the calcined material was crushed for about 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a rocking shaker with zirconia beads with a diameter of about 3 mm. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at about 110°C for 3 hours, and then crushed for about 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0106] Comparative Example 5 Compound powder (1-1) was calcined in an electric furnace at 900°C for 10 hours. The calcined material was then crushed for approximately 30 seconds using a Force Mill pulverizer. Wet grinding was performed at 640 rpm for 60 minutes using a jet mill with zirconia beads approximately 3 mm in diameter. Then, solid-liquid separation was performed by sieving with suction filtration using a sieve with a mesh size of 300 μm to obtain the desired average particle size. After that, this powder was mixed with pure water and allowed to stand until natural sedimentation occurred, followed by washing with decantation. Then, the same solid-liquid separation was performed again. The particles after solid-liquid separation were dried at approximately 110°C for 3 hours, and then crushed for approximately 30 seconds using a Force Mill pulverizer to obtain a composite powder.

[0107] Method for Measuring Circularity The obtained composite powder sample was observed at a magnification of 2500x using a scanning electron microscope (SU3500, Hitachi High-Technologies Corporation), and three SEM images were obtained. For each of the three obtained SEM images, image adjustment was performed by binarization of the particles and background. Subsequently, image analysis was performed on each of the 100 particles in the image. Using the image processing software ImageJ, drawing was performed along the particles, and after all drawing was completed, particle analysis was performed to obtain the average area and average circumference of each particle. Then, the circularity for one SEM image was calculated using equation (3). The arithmetic mean of the sphericity obtained from the three images was taken as the circularity (sphericity) of the composite powder. Circularity of one particle = 4π × (average area of ​​one particle) / (average circumference of one particle) ２ ... (3)

[0108] Method for measuring average particle size: After dispersing the obtained composite powder sample in pure water by irradiating it with ultrasound (40W, 3 minutes), the cumulative particle size D at 10% of the cumulative volume is measured using a particle size distribution analyzer (Microtrac (product name) MT-3300EXII (model number) manufactured by Microtrac-Bell Co., Ltd.) by laser diffraction scattering particle size distribution analysis. １０ Volume cumulative particle size D at a cumulative volume of 50% ５０ , and volume cumulative particle size D at 90% of cumulative volume ９０ We measured it.

[0109] XRD Peak Observation and Intensity Ratio Measurement Method For the samples obtained in each example and comparative example, peaks were observed by scanning with a powder X-ray diffractometer (Rigaku Corporation "MiniFlex2") at room temperature using Cu-Kα rays under the following conditions: tube voltage 30kV, tube current 15mA, scanning speed 5° / min, and scanning angle 2θ = 5° to 80°. Other operating conditions for powder X-ray diffraction were as follows: Slit: DS-SS; 1.25 degrees, RS; 0.3 mm Monochromator graphite step: 0.02° Counting method: constant counting method X-ray analysis software: PDXL2 Version 2.9.1.0 The XRD intensity ratio 1(-602) / (022) was measured at 30°C and 100°C, respectively, by operating the powder X-ray diffractometer under the above conditions. In addition, the XRD intensity ratio 2(20-1) / (022) was measured at 30°C and 120°C, respectively. Here, the peak intensity of "(-602)" refers to the peak intensity of the (-602) plane that appears at diffraction angles 2θ = 29.3 to 29.55°, the peak intensity of "(022)" refers to the peak intensity of the (022) plane that appears at diffraction angles 2θ = 29.6 to 29.7°, and the peak intensity of "(20-1)" refers to the peak intensity of the (20-1) plane that appears at 30.0 to 30.2°.

[0110] Preparation of a sintered body from powder only and measurement of the dimensional change ratio (ΔL / L) by TMA: 1 g of composite powder, 0.1 g of a 10% granulated binder (PV-217, manufactured by AS ONE) solution, and 0.2 g of ethanol were mixed in an agate mortar. The mixture was placed into a tablet molding die and molded into a tablet using a pressure press to obtain a molded body measuring 10 mm (diameter) x 5 mm (height). The molded body was dried at 110°C for 1 hour, and then fired at the firing temperature listed in Table 1 to create a sintered body. Subsequently, the dimensional change ratio of the sintered body was measured.

[0111] The measurement conditions for the dimensional change ratio using TMA were as follows: • Apparatus: TA7000 (Hitachi High-Tech Thermomechanical Analyzer TMA7000 series) • One cycle only: The sample was heated from 30°C to 250°C in an atmospheric environment at a heating rate of 6°C / min.

[0112] Table 1 shows the types of compound powders and oxides used in the composite powders of each example and comparative example, the amount of oxide blended per 100 parts by weight of compound powder, and the calcination temperature of the mixed powder. Table 2 shows the particle circularity, average particle diameter, XRD intensity ratio, and dimensional change ratio of the composite powders of each example and comparative example. From the results shown in Table 2, it can be seen that the composite powders from each example have high particle circularity (i.e., perfectly spherical) even at relatively low calcination temperatures.

[0113]

[0114]

[0115] The composite powder, which is a negative thermal expansion material obtained by the novel manufacturing method according to the present invention, has high sphericity and provides a material that does not cause a decrease in the fluidity of the composition or an increase in viscosity even when mixed with a matrix material. Therefore, it is possible to suppress the occurrence of product defects during the manufacturing of highly advanced electronic and optical equipment, fuel cells, sensors, etc., as well as damage and deterioration during repeated use. Furthermore, it is possible to reduce waste during manufacturing and use, and to reduce energy costs. In these respects, the composite powder, which is a negative thermal expansion material obtained by the novel manufacturing method according to the present invention, enables the sustainable management and efficient use of natural resources and promotes decarbonization (carbon neutrality) in the manufacturing and use of negative thermal expansion materials and electronic equipment, etc.

Claims

(a) A step of providing a powder of a compound comprising at least one selected from the group consisting of Zn, Mg, and P, wherein the compound is a negative thermal expansion material. (b) A step of mixing an oxide of an element, including at least one selected from the group consisting of elements belonging to group 5 or 6 of the periodic table, Li, and B, in an amount of 0.01 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the powder of the compound provided in step (a), to form a mixed powder, and (c) A step of obtaining a composite powder by calcining the mixed powder formed in step (b) above. A method for producing a compound powder containing [a specific compound]. 　 The method according to claim 1, wherein the oxide used in step (b) comprises at least one oxide selected from the group consisting of V, Nb, Ta, Cr, Mo, and W, which belong to group 5 or 6 of the periodic table. 　 The method according to claim 1, wherein the oxide used in step (b) comprises at least one oxide selected from the group consisting of V and Mo belonging to group 5 or group 6 of the periodic table. 　 The method according to claim 1, wherein the oxide used in step (b) includes an oxide having a melting point of 650°C or higher and 950°C or lower. 　 The method according to claim 1, wherein the oxide used in step (b) includes an oxide that is in powder or liquid form. 　 The method according to claim 1, wherein the circularity of the composite powder is 0.75 or more and 1.00 or less. 　 The method according to claim 1, wherein the content of uranium (U) and thorium (Th) in the composite powder is 1 ppm by mass or less, and the content of lead (Pb) and bismuth (Bi) in the composite powder is 30 ppm by mass or less. 　 A method for producing a resin composition, comprising obtaining a resin composition by combining the composite powder and resin component described in claim 1. 　 The method according to claim 8, further comprising obtaining a resin composition by combining the composite powder and resin component described in claim 1 with a curing agent. 　 The alpha dose of the resin composition is 0.0200 cph / cm². ２ The method according to claim 8, which is as follows: 　 A method for producing a powder mixture, comprising obtaining a powder mixture by combining the composite powder described in claim 1 with silica powder or other thermally conductive powder. 　 A method for using the resin composition described in claim 8, comprising encapsulating an electronic component with the resin composition. 　 A method for using the resin composition described in claim 8, comprising sealing an electronic component as an underfill of the resin composition. 　 A resin composition is obtained by combining the composite powder and resin component described in claim 1. Applying the resin composition to the first member, Applying the resin composition to the first member simultaneously with or after the application of the resin composition to the first member, thereby obtaining a component assembly in which the resin composition is sealed between the first and second members, and The process includes sealing the space between the first and second members with the resin composition by pressing the member assembly under heating, either simultaneously with or after obtaining the member assembly. Manufacturing methods for electronic components.

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