New compound powder

Abstract

Provided is a novel compound powder that can be used as a negative thermal expansion material that exhibits negative thermal expansion properties in a lower temperature range and has a higher thermal shrinkage rate. The compound powder contains at least one element A selected from a specific element group such as P, and is a composite including base particles formed from a compound containing element A and O (oxygen), and a coating layer formed from a metal compound containing Ca and element A that coats the surface of the base particles. The compound powder has negative thermal expansion properties. This compound powder may be a compound powder having negative thermal expansion properties, in which a sample of the compound powder and pure water are placed in a pressure-resistant container and sealed at room temperature, and then heated and pressurized under specified conditions to perform solid-liquid separation of the treated liquid, followed by removal of insoluble matter, and the filtrate is used as a test liquid for an ion elution test. The amount of at least one ion of element A eluted into the test liquid is 3,000 ppm by mass or less per 1 g of the sample.

Description

[Technical Field]

[0001] The present invention relates to a novel compound powder that includes a Ca (calcium)-containing coating layer and has negative thermal expansion properties. The present invention also relates to a novel compound powder that preferably includes a Ca (calcium)-containing coating layer, has negative thermal expansion properties, and can suppress the elution of specific types of ions under predetermined conditions. [Background technology]

[0002] In recent years, there has been a strong demand for controlling and suppressing the thermal expansion of solid materials in technological fields that require precision, such as highly advanced electronic and optical devices, fuel cells, and sensors. In particular, when combining multiple materials to construct precision equipment such as semiconductor devices, which require nanometer-level precision, differences in the thermal expansion coefficients between the materials can cause serious problems such as misalignment, interfacial delamination, wire breakage, warping, and cracks. Therefore, there is a demand for technology that can precisely control thermal expansion.

[0003] While many substances thermally expand with increasing temperature, it is also known that there are rare negative thermal expansion materials with a negative coefficient of thermal expansion, which means that their volume decreases with increasing temperature. One technique for controlling the thermal expansion of precision equipment is to control the thermal expansion coefficient of the entire equipment by adding a negative thermal expansion material to a matrix material (resin, glass, metal, etc.) with a large positive coefficient of thermal expansion, in combination with a material (e.g., silica) with a low positive coefficient of thermal expansion as needed. Examples of negative thermal expansion materials include β-eucryptite, zirconium tungstate (ZrW2O8), zirconium tungstate phosphate (Zr2WO4(PO4)2), Zn x CD 1-x (CN)2, manganese nitride, bismuth-nickel-iron oxide, etc. are known.

[0004] For example, Patent Document 1 discloses a negative thermal expansion material ZrO3, which is a powder having a particle size distribution polarized into small particles having a particle size within a predetermined range and large particles having a particle size within a predetermined range, and is mixed with raw materials obtained by mixing tungsten trioxide WO3 at a molar ratio of 2 with zirconium oxide ZrO2 and a substitution element X corresponding to the substitution amount x at a stoichiometric ratio of 1, and then the raw material powder is placed in a desired mold and sintered. (1-x) X x A method for synthesizing W2O8 (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 enabling the synthesis of large, high-density heat-shrinkable ceramics without press-molding raw material powder. In addition to Patent Document 1, development of new negative thermal expansion materials with various compositions and properties and methods for producing them is underway.

[0005] For example, Patent Document 2 reports a negative thermal expansion material containing at least one element selected from Mg, Al, Zn, etc. and / or an oxide represented by a general formula containing Cu, V, and P. Patent Document 3 reports a sealing material having a negative coefficient of thermal expansion, which includes a lead sealing glass and a mill addition of a pyrophosphate crystalline material made of magnesium pyrophosphate (Mg2P2O7), in particular, a crystallized glass consisting essentially of MgO and P2O5 present in a molar ratio that is approximately stoichiometric to magnesium pyrophosphate. Patent Document 4 reports a negative thermal expansion material of crystallized phosphate glass particles essentially consisting of P2O5 and one cation selected from magnesium, zinc, aluminum, etc., and a mixture of an organic polymer. Patent Document 5 reports a 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 shows that the amount of phosphorus ions eluted from the modified zirconium tungstate phosphate under certain conditions can be suppressed by such surface modification. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-342075 [Patent Document 2] International Publication No. 2022 / 114004 [Patent Document 3] U.S. Patent No. 5,089,445 [Patent Document 4] Japanese Patent Application Publication No. 08-048809 [Patent Document 5] Japanese Patent Publication No. 2020-147486 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, in precision equipment such as semiconductor devices that require highly accurate thermal expansion control, the actual heat cycle of the equipment is often at temperatures below 150°C, so there is a demand for materials that exhibit negative thermal expansion properties in such temperature ranges. However, many conventional negative thermal expansion materials only exhibit negative thermal expansion properties at temperatures higher than 150°C. Therefore, research is ongoing into specific compositions of negative thermal expansion materials that exhibit negative thermal expansion properties in lower temperature ranges, for example, below 150°C, and that 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 by mixing them with a matrix material (such as resin, glass, or metal). For example, when a resin is used as the matrix material, trace amounts of ions of the elements constituting the negative thermal expansion material may leach into the matrix resin as impurities. When a negative thermal expansion material is used in precision instruments such as semiconductor devices, it is preferable that the electrical conductivity of the negative thermal expansion material be lower (i.e., that the volume resistivity be higher). However, unfortunately, the leach-out of elemental ion impurities from the negative thermal expansion material into the matrix resin can impair the structural stability of the material itself, preventing stable performance of the negative thermal expansion properties and even increasing electrical conductivity. Therefore, it is desirable to provide a negative thermal expansion material in which the leach-out of elemental ions is suppressed and, preferably, electrical conductivity is maintained low.

[0009] Therefore, an object of the present invention is to provide a novel compound powder that exhibits negative thermal expansion properties in a lower temperature range and can be used as a negative thermal expansion material, preferably having a higher thermal shrinkage rate. Another object of the present invention is to provide a novel compound powder that exhibits negative thermal expansion properties in a lower temperature range, can be used as a negative thermal expansion material preferably having a higher thermal shrinkage rate, and is suppressed from leaching out specific types of elemental ions that are impurities. Yet another object of the present invention is to provide a novel compound powder that exhibits negative thermal expansion characteristics in a lower temperature range, can be used as a negative thermal expansion material preferably having a higher thermal shrinkage rate, and is inhibited from leaching out specific types of element ions that are impurities, thereby maintaining low electrical conductivity. [Means for solving the problem]

[0010] As a result of extensive research, the inventors have discovered a novel compound powder that exhibits negative thermal expansion properties in a lower temperature range and can be used as a negative thermal expansion material, preferably with a higher thermal shrinkage rate. The compound powder is a composite comprising base particles formed from a compound containing a specific type of element selected from a group of elements including P and O (oxygen), and a coating layer formed from Ca and a metal compound containing the specific type of element that coats the surface of the base particles, and has completed the present invention. Furthermore, the inventors have discovered a novel compound powder as a preferred embodiment of the present invention, which exhibits negative thermal expansion properties in a lower temperature range, can be used as a negative thermal expansion material preferably having a higher thermal shrinkage rate, and in which the elution of specific element ions is suppressed. The compound powder is a composite comprising base particles formed from a compound containing a specific element selected from a group of elements including P and O (oxygen), and a coating layer formed from a metal compound containing Ca and the specific element that coats the surface of the base particle, and in which the amount of at least one ion of the specific element eluted in an ion elution test under specified conditions is 3000 mass ppm or less per 1 g of sample.

[0011] That is, the compound powder according to the present invention is as follows: A compound powder containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, The compound powder is a substrate particle formed from a compound containing elements A and O (oxygen); and a composite including a coating layer formed from a metal compound containing Ca and element A, the coating layer coating the surface of the base particle, It has a temperature range in which the coefficient of linear expansion (α) is less than 0 ppm / K at least in the temperature range of 0°C to 70°C, or it has a temperature range in which the dimensional change ratio (ΔL / L) is less than 0 at least in the temperature range of 0°C to 70°C, or it has a temperature range in which the dimensional change ratio (ΔL / L) is less than -0.5 x 10 at least in the temperature range of 30°C to 70°C. -3 having a dimensional change ratio (ΔL / L) that is less than or equal to Compound powder.

[0012] The method for producing a compound powder according to the present invention is as follows. A method for producing a compound powder containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, comprising the steps of: providing a substrate particle formed from a compound containing the elements A and O (oxygen); a step of applying a coating medium containing a Ca-containing compound onto the surface of the base particle, and firing the coating medium to obtain a composite including a coating layer formed from a metal compound containing Ca and element A; The compound powder has a temperature range in which the linear expansion coefficient (α) is less than 0 ppm / K at least in the temperature range of 0°C or more and 70°C or less, or has a temperature range in which the dimensional change ratio (ΔL / L) is less than 0 at least in the temperature range of 0°C or more and 70°C or less, or has a temperature range in which the dimensional change ratio (ΔL / L) is less than -0.5 × 10 at least in the temperature range of 30°C or more and 70°C or less. -3 having a dimensional change ratio (ΔL / L) that is less than or equal to A method for producing the compound powder.

[0013] In this specification, the "ions" of at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V (ions whose elution amount is measured in the ion elution test according to a preferred embodiment of the present invention) include ions bonded to other atoms (single or multiple atoms) and ions of different valences, as long as they contain a specific element A. For example, P ions include PO4 3- , HPO4 2- , H2PO4 - , P2O7 4- , P3O 10 5- , PO3 - Includes: [Effects of the Invention]

[0014] The compound powder according to the present invention can be used as a negative thermal expansion material that exhibits negative thermal expansion characteristics in a lower temperature range and preferably has a higher thermal shrinkage rate. Furthermore, according to a preferred embodiment, a compound powder can be obtained in which the elution of at least one ion of a specific element such as P is suppressed. Furthermore, according to a preferred embodiment, a compound powder can be obtained in which the electrical conductivity is maintained low, i.e., the volume resistivity, which is an index of insulating properties, is increased. According to the method for producing a compound powder of the present invention, by the simple means of applying a coating medium containing a Ca-containing compound to base particles and firing them, it is possible to obtain a compound powder that exhibits negative thermal expansion properties in a lower temperature range, can be used as a negative thermal expansion material preferably having a higher thermal shrinkage rate, and in which the elution of at least one ion of a specific type of element such as P is effectively suppressed. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Compound powder according to the present invention> The compound powder of the present invention is (a) a base particle formed from a compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O (oxygen); (b) a coating layer formed from a metal compound containing Ca and element A that coats the surface of the base particle (a); is a complex compound comprising It has a temperature range in which the coefficient of linear expansion (α) is less than 0 ppm / K at least in the temperature range of 0°C to 70°C, or it has a temperature range in which the dimensional change ratio (ΔL / L) is less than 0 at least in the temperature range of 0°C to 70°C, or it has a temperature range in which the dimensional change ratio (ΔL / L) is less than -0.5 x 10 at least in the temperature range of 30°C to 70°C. -3 The dimensional change ratio (ΔL / L) is equal to or less than 0°C, i.e., the negative thermal expansion property is defined as above at least in the temperature range of 0°C to 70°C. It is a compound powder containing element A.

[0016] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O (oxygen), which forms the base particle (a), is not particularly limited as long as it is a compound containing these specific elements A and O. The compound containing at least one element A and O may be a compound containing any two or more elements A and O selected from the group consisting of P, Zn, Cu, Mg, and V. Furthermore, the compound containing at least one element A and O may be a mixture of any two or more compounds in any ratio.

[0017] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O (oxygen), which forms the base particle (a), is a negative thermal expansion material having a negative thermal expansion coefficient (negative thermal expansion coefficient) that exhibits a characteristic of decreasing in volume with increasing temperature. Such a negative thermal expansion material may have a linear expansion coefficient (α: as defined below) of typically less than 0 ppm / K, preferably less than -10 ppm / K, more preferably less than -20 ppm / K, even more preferably less than -30 ppm / K, and even more preferably less than -40 ppm / K, in a temperature range typically between -200°C and 500°C, preferably between 0°C and 200°C, and more preferably greater than room temperature (e.g., between 0°C and 10°C, 20°C, or 30°C), and less than 150°C, 70°C, or 50°C. By using such a negative thermal expansion material that exhibits a low linear expansion coefficient within an appropriate temperature range as the compound containing elements A and O that forms the base particle (a), it is possible to obtain a compound powder that has negative thermal expansion properties that are not significantly different from those of the base particle, even after forming a composite including a thin coating layer (b) thereon.

[0018] In this specification, the "linear expansion coefficient (α)" is defined by the following formula (A). Linear expansion coefficient (α) [unit: ppm / K] = (1 / L) × (ΔL / ΔT) × 10 6 ...Formula (A) In the formula, L refers to the length of the sample (μm), ΔL refers to the change in sample length (μm) over the specified temperature range, and ΔT refers to the temperature difference (K) over the specified temperature range. In this specification, the "dimensional change ratio," which is the ratio of change in sample length within a specified temperature range, is defined by the following formula (B). Dimensional change ratio (unitless) = ΔL / L Formula (B) where ΔL and L are as defined above. The linear expansion coefficient (α) and the dimensional change ratio ΔL / L are expressed by the following relationship: Linear expansion coefficient (α)[ppm / K] = {(ΔL / L) / ΔT}×10 6 The definitions and relational expressions regarding the linear expansion coefficient (α) and the dimensional change ratio (ΔL / L) herein can be similarly applied to the compound powders of any of the embodiments described below.

[0019] In one embodiment, the compound containing element A and O (oxygen) forming the base particle (a) of the compound powder may have a temperature range in which the dimensional change ratio (ΔL / L) is usually less than 0, preferably −0.5×10 in any range included in the temperature range of −200° C. or higher and 500° C. or lower, preferably in any range included in the temperature range of 0° C. or higher and 200° C. or lower, 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) and 150° C. or lower, 70° C. or lower, or 50° C. or lower. -3 The temperature range may be less than or equal to -1×10 -3 and even more preferably has a temperature range of -2×10 -3 or less, and more preferably -3×10 -3In another embodiment, the compound containing elements A and O forming the base particle (a) has a dimensional change ratio (ΔL / L) of -5×10 or less in any range typically included in the temperature range of -200°C or more and 500°C or less, preferably in any range included in the temperature range of 0°C or more and 200°C or less, more preferably in the temperature range of room temperature or more (for example, 0°C or more, 10°C or more, 20°C or more, or 30°C or more) and 150°C or less. -3 may have a temperature range of -6×10 -3 may have a temperature range of -7×10 -3 may have a temperature range of -8×10 -3 or -10 x 10 -3 The temperature range may be as follows:

[0020] The dimensional change ratio (ΔL / L: the rate of change in length due to linear expansion) of the base particle in this specification may be measured by mixing the base particle with a resin component to form a resin composition, or by measuring the base particle in a powder compact (unsintered product) state or by sintering this powder compact. The dimensional change ratio can be measured using a thermomechanical analyzer (TMA), such as a Hitachi High-Tech TA7000. The description here can also be applied to the base particle constituting the compound powder of any of the embodiments described below. When calculating the linear expansion coefficient (α) using the above formula (A), the sample length in mm displayed on the above device is set to 10 3 This can be converted to the unit μm by multiplying the unit by 1 / 2.

[0021] By including base particles (a) formed from a compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O (oxygen), a negative thermal expansion material can be obtained that exhibits negative thermal expansion properties in a lower temperature range. Furthermore, by preferably selecting an oxide of a metal containing P and at least one element selected from the group consisting of Zn, Cu, Mg, Ca, and V, a negative thermal expansion material with a higher thermal shrinkage rate can be obtained.

[0022] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V and O (oxygen) forming the base particle (a) is, for example, a compound represented by the general formula: Zn 2-x T x P 2-y A y O 7±δ (T contains 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 contains at least one element selected from Al, Si, V, Ge, and Sn, and satisfies 0≦x<2, 0≦y≦2; and δ is a value determined so as to satisfy the charge neutrality condition, except for (x,y)=(0,0) and (0,2).) In this specification, the "charge-neutral condition" does not have to be completely neutral, and may include a composition with oxygen deficiency or excess oxygen within the range acceptable for the compound.

[0023] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V and O (oxygen) forming the base particle (a) is, for example, a compound represented by the general formula: Cu 2-x R x V 2-y P y O 7±δ(R contains at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, and Sn, satisfies 0 ≦ x ≦ 2 and 0 < y < 2, and δ is a value determined to satisfy the charge neutrality condition.) It may contain at least one kind of oxide represented by.

[0024] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V that forms the base material particles (a) and O (oxygen) is, for example, a general formula in which Al atoms are solid-dissolved: Cu x M y V z O t±δ (In the formula, M represents a metal element with an atomic number of 11 or more other than Cu, V, and Al, preferably one or more metal elements selected from Zn, Ga, Fe, Mg, Co, Mn, Ba, and Ca. 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. However, 1.00 ≦ x + y ≦ 3.00. Also, when the M element is contained, the number of moles of Al atoms in terms of atoms > the number of moles of M atoms in terms of atoms.) It may contain at least one kind of oxide represented by.

[0025] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V that forms the base material particles (a) and O (oxygen) is, for example, a general formula in which Li atoms are solid-dissolved: (Cu x M y )(V a P b )O t±δ(In the formula, M represents a metal element having an atomic number of 11 or more other than Cu and V, preferably one or more selected from Zn, Ga, Fe, Mg, Co, Mn, Al, Ba, and Ca. x is 1.60 ≦ x ≦ 2.40, y is 0.00 ≦ y ≦ 0.40, a is 1.60 ≦ a ≦ 2.40, b is 0.00 ≦ b ≦ 0.40, t is 5.00 ≦ t ≦ 9.00, and δ is a value determined to satisfy the charge neutrality condition. However, 1.60 ≦ x + y ≦ 2.40 and 1.60 ≦ a + b ≦ 2.40.) It may contain at least one kind of oxide represented by.

[0026] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V forming the base material particles (a) and O (oxygen) is, for example, the general formula: Zr x (WO4) y±δ1 (PO4) 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 oxide represented by.

[0027] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V forming the base material particles (a) and O (oxygen) is, for example, the 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, and 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 oxide represented by.

[0028] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V forming the base material particles (a) and O (oxygen) is, for example, the general formula: Zr 2.00-b M b SY P Z O 12.00±δ (wherein M is at least one selected from Ti, Ce, Sn, Mn, Hf, Ir, Pb, Pd, Cr, W, and Mo, and 0≦b<2.00, 0.30≦Y≦1.00, Z>2.00, and δ are values ​​determined so as to satisfy the charge neutrality condition.)

[0029] In the compound powder, the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V and O (oxygen) forming the base particle (a) is, for example, a compound represented by the general formula: Ti 2-x M x O 3±δ (M includes at least one element selected from Mg, Al, Si, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi, and satisfies 0≦x<2, and δ is a value determined so as to satisfy the charge neutrality condition. However, M includes at least one element selected from the group consisting of Zn, Cu, Mg, and V.)

[0030] In the compound powder, the metal compound forming the coating layer (b) that coats the surface of the base particle (a) is not particularly limited as long as it contains Ca and the element A. The metal compound forming the coating layer (b) that coats the surface of the base particle (a) may contain at least one metal compound selected from the group consisting of oxides, oxynitrides, nitrides, carbides, and sulfides of the element A and Ca. Preferably, the metal compound forming the coating layer (b) that coats the surface of the base particle (a) may contain or consist of at least one oxide of the element A and Ca (i.e., a compound containing the element A, Ca, and O (oxygen)). In this way, by including in the coating layer (b) a metal compound of a specific type of element A, such as P, derived from the base particle (a) and Ca, it is possible to obtain a compound powder in which the elution of at least one type of ion of element A is suppressed. Furthermore, by preferably selecting the type of element A and the metal compound, it is possible to obtain a compound powder in which the electrical conductivity is maintained low, i.e., the volume resistivity is increased.

[0031] In a preferred embodiment of the compound powder, the element A in the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V and O (oxygen) that forms the base particle (a) contains P, and the metal compound containing Ca and the element A that forms the coating layer (b) that coats the surface of the base particle (a) may contain a Ca-PO-based composite oxide. In another preferred embodiment, the element A of the compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O, which forms the base particle (a), includes at least one element selected from the group consisting of Zn, Cu, Mg, and V, and the metal compound containing Ca and the element A, which forms the coating layer (b) that coats the surface of the base particle (a), may include a Ca-Zn-O based composite oxide, a Ca-Cu-O based composite oxide, a Ca-Mg-O based composite oxide, a Ca-VO based composite oxide, or a mixture of two or more of these composite oxides. In still another preferred embodiment, the element A in the compound containing O and at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V that forms the base particle (a) contains P and one or more elements selected from the group consisting of Zn, Cu, Mg, and V, and the metal compound containing Ca and the element A that forms the coating layer (b) that coats the surface of the base particle (a) may contain a Ca-Zn-PO-based composite oxide, a Ca-Cu-PO-based composite oxide, a Ca-Mg-PO-based composite oxide, a Ca-VPO-based composite oxide, or a mixture of two or more of these composite oxides. By selecting specific types of element A and metal compound, it is possible to effectively suppress the elution of at least one ion of element A, and obtain a compound powder in which the electrical conductivity is kept sufficiently low, i.e., the volume resistivity is greatly increased. From this viewpoint, it is preferable that the metal compound forming the coating layer (b) contains or consists of at least one oxide of element A and Ca (i.e., a compound containing element A, Ca, and O (oxygen)). In a preferred embodiment, the compound that forms the base particle (a) and contains at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O (oxygen), may include one or more Zn-Mg-PO-based compounds. Particularly preferred examples of such Zn-Mg-PO-based compounds include Zn 2-x Mg x Examples of oxides include oxides represented by the formula P2O7. Here, x may be 0.1 or more and 0.8, and preferably 0.2 or more and 0.5 or less. By using base particles (a) of such oxides, it is possible to obtain a compound powder that is easy to sinter, has high negative thermal expansion properties, and is dense and stable.

[0032] In the compound powder, the thickness of the coating layer (b) is not particularly limited, but may be, for example, 0.01 μm to 5 μm, preferably 0.02 μm to 4 μm, 0.03 μm to 3 μm, 0.04 μm to 2 μm, 0.05 μm to 1 μm, or 0.1 μm to 1 μm. The thickness of the coating layer (b) can be observed from an SEM image of the compound powder.

[0033] The compound powder may optionally be further surface-treated with respect to the coating layer (b). By surface-treating the compound powder with a predetermined surface-treatment compound, the insulating properties and chemical resistance can be improved, and this can contribute to improving wettability with resins.

[0034] Examples of surface treatment compounds for the coating layer (b) include, but are not limited to, silane coupling agents, aluminate coupling agents, titanate coupling agents, zirconium coupling agents, organic compounds such as organic carboxylic acids and organic amines, and inorganic compounds such as silicon dioxide, aluminum oxide, zinc oxide, and titanium oxide. These surface treatment compounds can be used alone or in a mixture of two or more types. For example, various silane coupling agents such as epoxy, amino, vinyl, methacrylic, acrylic, mercapto, and alkyl silane coupling agents can be used as the silane coupling agent for the surface treatment compound.

[0035] Even when a compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V and O (oxygen) forming the base particle (a) is made into a composite compound powder having a coating layer formed on its surface from a metal compound containing Ca and the element A, it is preferable that such composite compound powder maintains negative thermal expansion characteristics substantially equivalent to those of the compound forming the base particle (a). Therefore, as described above for the base particle (a), the compound powder, which is a negative thermal expansion material, may have a temperature range in which the linear expansion coefficient (α) is usually less than 0 ppm / K, preferably less than -10 ppm / K, more preferably less than -20 ppm / K, even more preferably less than -30 ppm / K, and even more preferably less than -40 ppm / K, in any temperature range of -200°C or more to 500°C or less, preferably in any temperature range of 0°C or more to 200°C or less, and more preferably in a temperature range of room temperature or more (e.g., 0°C or more, 10°C or more, 20°C or more, or 30°C or more) to 150°C or less, 70°C or less, or 50°C or less.

[0036] Furthermore, as described above for the base particle (a), the compound powder that is a negative thermal expansion material may have a temperature range in which the dimensional change ratio (ΔL / L) is usually less than 0, preferably -0.5×10, in any range included in the temperature range of usually -200°C or more and 500°C or less, preferably in any range included in the temperature range of 0°C or more and 200°C or less, more preferably in the temperature range of room temperature or more (for example, 0°C or more, 10°C or more, 20°C or more, or 30°C or more) and 150°C or less, 70°C or less, or 50°C or less. -3 The temperature range may be less than or equal to -1×10 -3 and even more preferably has a temperature range of -2×10 -3 or less, and more preferably -3×10 -3 In another embodiment, the compound powder has a dimensional change ratio (ΔL / L) of -5×10 or less in any range typically included in the temperature range of -200°C or more and 500°C or less, preferably in any range included in the temperature range of 0°C or more and 200°C or less, more preferably in the temperature range of room temperature or more (e.g., 0°C or more, 10°C or more, 20°C or more, or 30°C or more) and 150°C or less or 70°C or less. -3 The temperature range may be less than or equal to -6×10 -3 The temperature range may be less than or equal to -7×10 -3 or less, and even more preferably -8×10 -3 or less, and more preferably -10×10 -3 The temperature range may be as follows:

[0037] The dimensional change ratio (ΔL / L: the rate of change in length due to linear expansion) of the compound powder in this specification may be measured by mixing the compound powder with a resin component to form a resin composition. The dimensional change ratio can be measured using a thermomechanical analyzer (TMA), such as the TA7000 manufactured by Hitachi High-Technologies. The description here can be similarly applied to the compound powder of any of the embodiments described below.

[0038] By mixing two or more compound powders of negative thermal expansion materials, a material can be obtained that has two or more shrinkage temperature ranges and exhibits gradual thermal shrinkage. This makes it possible to suppress sudden shrinkage of the negative thermal expansion material. Therefore, for example, a resin composition containing two or more 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 negative thermal expansion material. The matters described here can be similarly applied to the compound powder of any of the embodiments described below.

[0039] The particle shape of the compound powder is not particularly limited and may be, for example, spherical, granular, plate-like, scaly, whisker-like, rod-like, filament-like, or crushed. From the viewpoints of achieving uniform mixing and dispersion when mixed with a positive thermal expansion material such as silica, suppressing wear on the raw material mixing container, and reducing the inclusion of impurities, it is preferable that the particle shape of the compound powder contains a large number of spherical particles. Furthermore, by containing a large number of spherical particles in the compound powder, the flowability of the resin composition is improved and an increase in viscosity can be suppressed, which is preferable. The compound powder can be processed into a powder compact. The compound powder or a resin composition containing the compound powder can be processed into various shapes such as a film material or a plate material.

[0040] The compound powder preferably contains a large amount of spherical particles with a sphericity (true sphericity) of 0.7 or more and 1.0 or less. The content of spherical particles in the compound powder may be 75% or more, preferably 80% or more, on a number basis, from the viewpoints of achieving uniform mixing and dispersion when mixed with a positive thermal expansion material such as silica, suppressing wear on the raw material mixing container, and reducing the inclusion of impurities. Furthermore, this has the advantage of improving the fluidity of the resin composition and suppressing an increase in viscosity. In this specification, the sphericity of a compound powder can be measured as follows. A sample of the compound powder was observed at 2500x magnification using a scanning electron microscope (SU3500, Hitachi High-Technologies Corporation) to obtain three SEM images. Each of the three SEM images was subjected to image adjustment, with binarization of the particles and background. Image analysis was then performed on each of the 100 particles in the image. Using the image processing software ImageJ, a drawing was performed along the particle. After all the drawings were completed, particle analysis was performed to obtain the average area and average perimeter of each particle. The sphericity of each SEM image was then calculated using equation (1). The arithmetic mean value of the sphericities obtained from the three images was taken as the sphericity (true sphericity). Sphericity of one particle = 4π x (average area of ​​one particle) / (average perimeter of one particle)^2 ···(1) The concept of sphericity or true sphericity of a compound powder, and the fact that the closer the numerical value is to 1, the more closely the particle shape resembles a sphere, have been known for some time. However, it is not known and is considered to be difficult to increase the sphericity of a compound powder to a level of 0.7 or more using the calculation method defined above, which is specific to the present application (this applies to any of the embodiments described below).

[0041] The average particle size of the compound powder (a composite of base particles and coating layer) is determined by the volume cumulative particle size D at 50% cumulative volume measured by a laser diffraction / scattering particle size distribution measurement method, from the viewpoint of dispersibility in matrix materials such as resin, glass, and metal. 50 The volume cumulative particle size D of the compound powder is preferably 0.05 μm or more and 100 μm or less. 50 More preferably, it may be 0.1 μm or more and 50 μm or less, 0.5 μm or more and 40 μm or less, 1 μm or more and 30 μm or less, 1 μm or more and 20 μm or less, or 1 μm or more and 10 μm or less.

[0042] The BET specific surface area of ​​the compound powder is 0.1m 2 / g or more 10m 2 / g or less. By having the BET specific surface area within this range, the dispersibility of the compound powder in matrix materials such as resins, glasses, and metals can be improved. The BET specific surface area of ​​the compound powder is more preferably 0.1 m 2 / g or more 8m 2 / g or less, and even more preferably 0.1m 2 / g or more 5m 2 / g or less, 0.1m 2 / g or more 4m 2 / g or less, 0.1m 2 / g or more 3m 2 / g or less, 0.1m 2 / g or more 2m 2 / g or less, or 0.1m 2 / g or more 1m 2 / g or less. Furthermore, from the viewpoint of dispersibility in matrix materials such as resins, glasses, and metals, the BET specific surface area of ​​the compound powder may preferably be 10 times or less the BET specific surface area of ​​the uncomposite base particles (a), and more preferably 5 times or less, 4 times or less, 3 times or less, 2 times or less, 1 time or less, or 0.5 times or less the BET specific surface area of ​​the base particles (a).

[0043] The volume resistivity of the compound powder is 1.0 × 10 at 25°C so that it can be suitably used in applications where insulation is required. 9 The volume resistivity of the compound powder is preferably 5.0×10 Ω·cm or more 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 more, or 1.0×10 12 It may be Ω·cm or more. In this specification, the volume resistivity of a compound powder can be measured, for example, by compressing the compound powder at a pressure of 63 MPa using a powder resistivity measurement system "MCP-PD51" manufactured by Nitto Seiko Analytech Co., Ltd. and measuring it according to the four-terminal method. For samples exceeding the measurement upper limit of this device, a pellet is separately compressed at a pressure of 63 MPa to prepare it, and the pellet can be measured using a high resistance meter Hiresta UX / MCP-HT800 manufactured by Nitto Seiko Analytech Co., Ltd.

[0044] The method for producing the compound powder is not particularly limited, but may be, for example, (1) providing a base particle (a) formed from a compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O (oxygen); (2) A step of applying a coating medium containing a Ca-containing compound onto the surface of the base particle (a) and firing the coating medium to obtain a composite containing a coating layer formed from a metal compound containing Ca and element A.

[0045] In step (1) of providing base particles (a) formed from a compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, and O (oxygen), a dry synthesis method or a liquid phase synthesis method (hydrothermal reaction method) can usually be appropriately selected and used.

[0046] The dry synthesis method for obtaining the base particles (a) is, for example, (i) preparing a raw material compound which is a single element or a mixture of multiple elements and which contains at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V; (ii) calcining the raw material compounds to obtain a primary calcined product; (iii) crushing and remixing the primary fired product, and then firing it again to obtain a secondary fired product; (iv) optionally, performing step (c) at least once more to obtain an additional calcined product; (v) crushing the secondary or additionally fired product; (vi) optionally, grinding the secondary or additional calcined product after crushing; (vii) optionally sieving the crushed secondary or additional calcined product, with or without washing with water and decanting; and (viii) Optionally, the method may include drying the sieved secondary or additional calcined product.

[0047] The raw material compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V is not particularly limited as long as it is a compound containing the desired element. The raw material compound may be a simple substance of at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V. Examples of raw material compounds containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V that are suitable for use in dry synthesis methods include one or more compounds containing the element and an oxygen atom, such as P2O5, ZnO, CuO, MgO, and VO5. For example, examples of P-containing compounds used as raw material compounds include one or more of phosphoric acid (H3PO4), diammonium hydrogen phosphate ((NH4)2HPO4), ammonium dihydrogen phosphate (NH4H2PO4), ammonium phosphate, pyrophosphoric acid, polyphosphoric acid, Zn2P2O7, Mg2P2O7, etc.

[0048] The firing temperature in each firing step 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, and 1200°C or lower, 1000°C or lower, or 900°C or lower. The firing temperature range in each firing step 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 a composite having the desired composition, it is preferable to set the firing temperature higher as the firing step progresses. The firing step may usually be repeated two or three times, but may be repeated four or more times if necessary.

[0049] The optional grinding of the crushed secondary fired product or additional fired product may be dry grinding or wet grinding. Dry grinding can be performed using, for example, a jet mill using an impact plate system or a jet mill using a system that causes particles to collide with each other. Wet grinding can be performed, for example, by adding pure water and, if necessary, a small amount of dispersant to the crushed fired product, and while stirring, feeding small-diameter beads such as zirconia beads into a media-agitation bead mill.

[0050] The sieving optionally performed on the pulverized calcined product is carried out to obtain a volume cumulative particle size D 50 An appropriate sieve can be selected to obtain a compound powder having the following formula: Washing with water and washing by decantation, which may be performed in conjunction with sieving, is preferably repeated until a desired conductivity (for example, 20 μS / cm or less) is achieved. The sieved fired product may optionally be dried, for example, at 50°C or higher and 200°C or lower, preferably 80°C or higher and 150°C or lower, for 30 minutes to 10 hours, preferably 1 hour to 8 hours.

[0051] The wet synthesis method for obtaining the base particle (a) is, for example, (i) preparing a raw material compound which is a single element or a mixture of multiple elements and which contains at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V; (ii) hydrothermally treating the raw compound to obtain a hydrothermally treated mixture; (iii) optionally, solid-liquid separation and washing of the hydrothermally treated mixture; (iv) drying the hydrothermally treated mixture; (v) calcining the dried mixture; may include:

[0052] The starting compound containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V is not particularly limited as long as it is a compound containing the desired element. The starting compound may be a simple substance of at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V. Examples of starting compounds containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V that are suitable for use in liquid-phase synthesis (hydrothermal reaction) include one or more of the following: chloride salts or hydrates thereof, oxychloride salts or hydrates thereof, acetate salts or hydrates thereof, oxyacetate salts or hydrates thereof, sulfate salts or hydrates thereof, nitrate salts or hydrates thereof, carbonate salts or hydrates thereof, ammonium carbonate salts or hydrates thereof, sodium carbonate salts or hydrates thereof, potassium carbonate salts or hydrates thereof, polyacids or salts or hydrates thereof, oxides or hydrates thereof, etc. The starting compound may optionally contain sulfuric acid as a sulfur source. For example, examples of P-containing compounds used as raw material compounds include one or more of phosphoric acid (H3PO4), diammonium hydrogen phosphate ((NH4)2HPO4), ammonium dihydrogen phosphate (NH4H2PO4), ammonium phosphate, pyrophosphoric acid, polyphosphoric acid, etc.

[0053] The conditions for hydrothermal treatment of the raw material compounds in the liquid phase synthesis method (hydrothermal reaction method) are not particularly limited, but for example, the reaction can be continuously carried out under pressure in a sealed container at 100°C or higher and 250°C or lower, preferably 110°C or higher and 230°C or lower, for example, 30 minutes or longer and 100 hours or shorter, preferably 1 hour or longer and 80 hours or shorter, 2 hours or longer and 60 hours or shorter, or 3 hours or longer and 40 hours or shorter.

[0054] Washing after solid-liquid separation in the liquid-phase synthesis method (hydrothermal reaction method) can be carried out, for example, by adding more water to perform solid-liquid separation or by washing with water. Such washing procedures can be repeated multiple times. If sulfur components are present in the system, they can be effectively removed by washing.

[0055] The hydrothermally treated mixture in the liquid phase synthesis method (hydrothermal reaction method) may be dried, 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. The temperature for calcining the dried mixture is not particularly limited, and may be, for example, 250°C or higher, 300°C or higher, or 350°C or higher, and 1200°C or lower, 1000°C or lower, or 900°C or lower.

[0056] In step (2) of the method for producing a compound powder, examples of Ca-containing compounds that can be used in the coating medium for forming the coating layer include, but are not limited to, ionic compounds that can release calcium ions in water, such as calcium hydroxide (Ca(OH)), calcium carbonate (CaCO), calcium chloride (CaCl), calcium oxide (CaO), calcium nitrate (Ca(NO)), calcium sulfate (CaSO), and calcium acetate (Ca(CHCOO)). The proportion (concentration) of the Ca-containing compound in the coating medium is not particularly limited, and may be, for example, 0.05% by mass to 10% by mass, and preferably 0.1% by mass to 5% by mass.

[0057] The solvent used in the coating medium (dispersion) usually contains a majority of water, and preferably is substantially all water. The solvent may contain other solvents, such as lower alcohols, that are miscible with water. In addition, the coating medium may contain a dispersant (dispersion promoter) in addition to the Ca-containing compound and the solvent. Examples of such dispersants include, but are not limited to, polycarboxylic acid-based dispersants such as ammonium polycarboxylate, polyacrylic acid-based dispersants, and polysulfonic acid-based dispersants. The dispersant can be used in an amount of, for example, 0.1 to 1 part by mass per 100 parts by mass of the Ca-containing compound and the solvent combined. It is preferable that the Ca-containing compound is dispersed more uniformly in the coating medium. Dispersion may be performed manually or mechanically. To achieve a uniform dispersion, ultrasonic dispersion may be used.

[0058] The application of a coating medium containing a Ca-containing compound to the surface of a base particle (a) involves mixing the base particle in the coating medium to form a mixture, thoroughly stirring the mixture, and then performing solid-liquid separation by filtration or the like, followed by drying as necessary to obtain a base particle having a Ca-containing compound applied to its surface. The ratio of the Ca-containing compound to the base particle is not particularly limited, but from the viewpoint of suppressing ion elution by forming a sufficient coating layer and maintaining negative thermal expansion properties, it may be, for example, 0.6% to 60% by mass, preferably 0.7% to 50% by mass, 0.8% to 40% by mass, 0.9% to 30% by mass, or 1% to 20% by mass. The mixture is usually stirred by mechanical means, for example, for about 5 minutes to 5 hours.

[0059] The base particles having the Ca-containing compound applied to their surfaces, obtained by solid-liquid separation after stirring, can be fired at, for example, 300°C or higher and 1500°C or lower, preferably 400°C or higher and 1200°C or lower, more preferably 500°C or higher and 1000°C or lower, for, for example, 30 minutes to 40 hours, preferably 1 hour to 30 hours, in order to reliably form a Ca-containing coating layer.

[0060] The fired product thus obtained may be washed by mixing and stirring with pure water, and then subjected to solid-liquid separation by removing the supernatant liquid. Such washing and solid-liquid separation treatments may be carried out once or multiple times, for example, 3 to 6 times. After these treatments, the solid content may be dried at a predetermined temperature (for example, 80°C to 150°C).

[0061] In this way, a compound powder can be obtained that is a composite comprising base particles and a coating layer formed from a metal compound containing Ca and element A that coats the surface of the base particles. The metal compound containing Ca and element A that constitutes the coating layer may include, for example, a Ca-PO-based composite oxide, a Ca-Zn-O-based composite oxide, a Ca-Cu-O-based composite oxide, a Ca-Mg-O-based composite oxide, a Ca-VO-based composite oxide, a Ca-Zn-PO-based composite oxide, a Ca-Cu-PO-based composite oxide, a Ca-Mg-PO-based composite oxide, a Ca-VPO-based composite oxide, or a mixture of two or more of these composite oxides. The metal compound containing Ca and element A that constitutes the coating layer may preferably include or consist of a metal compound containing Ca, element A, and O (oxygen).

[0062] Compound Powder According to a Preferred Embodiment In a preferred embodiment, the compound powder may have all of the essentially required properties described above or any of the preferred properties within those ranges. In addition, when 2 g of a sample of the compound powder and 40 ml of pure water are placed in a pressure-resistant container (e.g., a 100 ml autoclave made of polytetrafluoroethylene resin) at room temperature and sealed, the container is manually shaken for 1 minute, and then the sealed pressure-resistant container is heated at 121°C for 20 hours. After cooling to room temperature, the sealed pressure-resistant container is opened to remove the treated liquid, which is then subjected to solid-liquid separation using a 0.45 μm membrane filter. The filtrate from which the insoluble matter has been removed is used as a test liquid for an ion elution test (the same applies to each of the following embodiments), the amount of at least one ion of element A eluted into this test liquid may be 3,000 ppm by mass or less per 1 g of the sample.

[0063] With this compound powder, the amount of at least one type of ion of element A eluted in the ion elution test (i.e., the amount of ions that can become impurities in the eluted substance) is controlled to a predetermined upper limit or less, thereby maintaining the structural stability of the material itself, thereby stably exhibiting negative thermal expansion characteristics and effectively suppressing an increase in electrical conductivity.

[0064] In a preferred embodiment, the amount of at least one ion of element A eluted in the above-mentioned ion elution test of the compound powder may be preferably 2500 ppm by mass or less, more preferably 2000 ppm by mass or less, even more preferably 1500 ppm by mass or less, still more preferably 1000 ppm by mass or less, even more preferably 500 ppm by mass or less, even more preferably 100 ppm by mass or less, and still more preferably 50 ppm by mass or less, per 1 g of sample.

[0065] In a preferred embodiment, the amount of P ions eluted from the compound powder in the above-mentioned ion elution test may typically be 3000 ppm by mass or less, preferably 2500 ppm by mass or less, more preferably 2000 ppm by mass or less, even more preferably 1500 ppm by mass or less, still more preferably 1000 ppm by mass or less, even more preferably 500 ppm by mass or less, even more preferably 100 ppm by mass or less, and still more preferably 50 ppm by mass or less, per 1 g of sample.

[0066] In a preferred embodiment, the amount of at least one ion of element A eluted in the ion elution test of the compound powder preferably satisfies any one or more of the following (i) to (iv) in addition to the amount of eluted P ions being within the specific range, or when the amount of eluted P ions is outside the specific range: (i) the amount of Zn ions eluted in the ion elution test is 3000 ppm by mass or less, preferably 2500 ppm by mass or less, more preferably 2000 ppm by mass or less, even more preferably 1500 ppm by mass or less, still more preferably 1000 ppm by mass or less, even more preferably 500 ppm by mass or less, still more preferably 100 ppm by mass or less, and still more preferably 50 ppm by mass or less; (ii) the amount of Cu ions eluted in the ion elution test is 3000 ppm by mass or less, preferably 2500 ppm by mass or less, more preferably 2000 ppm by mass or less, even more preferably 1500 ppm by mass or less, still more preferably 1000 ppm by mass or less, even more preferably 500 ppm by mass or less, still more preferably 100 ppm by mass or less, and still more preferably 50 ppm by mass or less; (iii) the amount of Mg ions eluted in the ion elution test is 3000 ppm by mass or less, preferably 2500 ppm by mass or less, more preferably 2000 ppm by mass or less, even more preferably 1500 ppm by mass or less, still more preferably 1000 ppm by mass or less, even more preferably 500 ppm by mass or less, still more preferably 100 ppm by mass or less, and still more preferably 50 ppm by mass or less; and (iv) The amount of V ions eluted in the above-mentioned ion elution test is 3000 ppm by mass or less per gram of sample, preferably 2500 ppm by mass or less, more preferably 2000 ppm by mass or less, even more preferably 1500 ppm by mass or less, still more preferably 1000 ppm by mass or less, even more preferably 500 ppm by mass or less, still more preferably 100 ppm by mass or less, and still more preferably 50 ppm by mass or less. Satisfying one or more of (i) to (iv) above may include satisfying only (i) above, satisfying only (ii) above, satisfying only (iii) above, satisfying only (iv) above, satisfying (i) and (ii) above, satisfying (i) and (iii) above, satisfying (i) and (iv) above, satisfying (ii) and (iii) above, satisfying (ii) and (iv) above, satisfying (iii) and (iv) above, satisfying (i), (ii) and (iii) above, satisfying (i), (ii) and (iv) above, satisfying (i), (iii) and (iv) above, satisfying (ii), (iii) and (iv) above, or satisfying (i), (ii), (iii) and (iv) above.

[0067] <Resin composition> The compound powder according to any of the above-described embodiments can be combined with a resin component to form a resin composition. The type and amount of resin used in the resin composition are not particularly limited, and can be selected and adjusted as appropriate to obtain the targeted negative thermal expansion characteristics or other desired characteristics. The term "resin composition" referred to in this specification is intended to encompass both a composition that partially contains a solvent, such as water or an organic solvent, that is used when preparing the resin composition by mixing various components, and a composition that excludes a solvent, such as an organic solvent, that is used when preparing the resin composition by mixing various components and that can be removed under reduced pressure after preparation.

[0068] Examples of resins include, but are not limited to, 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; polystyrene resins such as ABS; polyacrylate resins; polyamide resins; polyimide resins; polyamideimide 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 polyether ether ketones; and mixtures of two or more of these. Among these resins, epoxy resins are preferred from the viewpoint of the balance of properties such as fast curing, mechanical properties, and heat resistance.

[0069] The amount of resin contained in the resin composition is not particularly limited, but may be typically 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, or 20% by mass or more and 70% by mass or less, relative to the total amount of the resin composition.

[0070] In addition to the compound powder and resin component, the resin composition may contain at least one type of inorganic material powder, such as silica (silicon dioxide), silicate, titanium oxide, 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 crushed, spherical, or an aggregate such as fumed silica. The inorganic material powder is preferably spherical to reduce the viscosity of the resin composition. For example, when the inorganic material powder is silica, it may be crystalline or amorphous. The total amount of the compound powder and inorganic material powder such as silica (if present) contained in the resin composition is not particularly limited, but may be typically 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, or 20% by mass or more and 70% by mass or less, based on the total amount of the resin composition.

[0071] The resin composition may contain a curing agent in addition to the compound powder and resin component. Any known curing agent may be used, including, for example, acid anhydride compounds, phenolic compounds, amine / amide compounds, and active ester compounds. The amount of curing agent contained in the resin composition is not particularly limited, but may be typically 0.05% by mass to 10% by mass, preferably 0.1% by mass to 5% by mass, or 0.5% by mass to 3% by mass, based on the total amount of the resin composition.

[0072] Examples of the acid anhydride compound curing agent that can be contained in the resin composition include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, maleic anhydride polypropylene glycol, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Examples of the phenolic compound curing agent that can be contained in the resin composition include dicyclopentadiene-phenol addition type resins, phenol aralkyl resins, naphthol aralkyl resins, triphenylolmethane 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.

[0073] Examples of the amine compound / amide compound curing agent that can be contained in the resin composition 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 and a dimer of linolenic acid and ethylenediamine. Examples of the active ester compounds that can be contained in the resin composition include compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Preferred examples of the active ester compounds include active ester compounds 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 the active ester compounds include active ester compounds obtained from a carboxylic acid compound or its halide with a phenol compound and / or a naphthol compound. Examples of the 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 halides thereof. 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 adduct resins.

[0074] Examples of other additives that can be included in the resin composition include inorganic fillers and fibers other than negative thermal expansion materials, lubricants and 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, friction improvers such as polysiloxanes, various coloring pigments, silane coupling agents, titanium coupling agents, dye colorants, plasticizers such as wax and silicone resins, 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 perspective of maintaining the negative thermal expansion properties and other properties of the resin composition, it may usually be 5% by mass or less, preferably 3% by mass or less, based on the total amount of the resin composition.

[0075] The alpha dose of the negative thermal expansion material and resin composition is 0.0200 cph / cm 2 The alpha dose of the negative thermal expansion material and the resin composition is preferably within this range, so that malfunctions caused by current noise generated by alpha rays can be suppressed when the negative thermal expansion material and the resin composition are used as a sealing material for semiconductor elements. The alpha dose of the negative thermal expansion material and the resin composition is more preferably 0.0150 cph / cm 2 or less, and even more preferably 0.0100 cph / cm 2 The alpha dose of the negative thermal expansion material and the resin composition may be 0.050 cph / cm or less. 2 It may be less than 0.020 cph / cm 2 It may be less than 0.010 cph / cm 2 It may be the following:

[0076] In this specification, the alpha dose may be measured using a semiconductor-type trace alpha ray energy distribution measuring device, or a measurement method using a gas proportional counter type measuring device or an ionization type measuring device based on the international standard JEDEC STANDARD. When a semiconductor-type trace alpha-ray energy distribution measuring device is used, measurement may be performed using, for example, the "KS-1000" manufactured by Hitachi, Ltd. When a semiconductor-type trace alpha-ray energy distribution measuring device is used, alcohol treatment may be performed as a pretreatment. As a more specific measurement method for measuring the alpha dose of a powder sample of a negative thermal expansion material using a semiconductor-type trace alpha ray energy distribution measurement device, the following procedure can be adopted. (i) Place the sample to be measured (10 g) and ethyl alcohol (25 ml) into a 50 ml beaker, and then disperse the sample in an ultrasonic cleaner for approximately 1 minute. (ii) Transfer the entire sample in the beaker to the sample stage so that the surface is uniform, and allow to dry naturally for approximately 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 sample stage after vacuum drying is used as a sample for measuring trace alpha rays. (v) The sample stage is placed in the chamber of the measurement device and measurements are performed for 200 hours. The effective measurement area is 169 cm. 2 (13cm x 13cm). When measuring the alpha dose of a resin composition, the resin composition can be placed directly on the sample stage. The actual measurement results obtained by the above procedure are used to determine the alpha dose, which is the net count value obtained by subtracting the background. The surface α dose measured in the range of 2.0 to 10 MeV using the above-mentioned device "KS-1000" manufactured by Hitachi, Ltd. may be taken as the α dose here.

[0077] Alpha radiation can be measured according to the international JEDEC STANDARD by the following procedure. (i) A gas flow type alpha ray dosimetry device is used. The sample to be measured is powder spread on a sample base, for example, with an area of ​​900 cm. 2A sample sheet formed into a sheet of α-rays is used. A sample sheet that satisfies the maximum measurement area depending on the device may be used. The sample sheet is placed as a measurement sample in the α-ray dosimetry device (gas proportional counter type or ionization type), and PR gas is purged into the device. The PR gas used is one that complies with the international JEDEC STANDARD. In other words, the PR gas used for measurement is radon (Rn) decay gas that has been filled into a gas cylinder containing a 90% argon-10% methane mixed gas for at least three weeks. (ii) The PR gas is allowed to flow into the α dose measuring device in which the sample sheet is placed for 12 hours, and the device is then left to stand, after which α dose measurement is carried out for 72 hours. (iii) The average alpha dose is expressed as cph / cm 2 If there are any abnormal points (such as counts due to device vibrations), the counts for that hour will be removed. For the above measurement method, the following equipment is used: Alpha ray counter: For example, the LACS-4000M manufactured by Sumika Chemical Analysis Center Co., Ltd. Alpha Science "Gas flow type alpha ray measuring device (MODEL-1950)" Ordela Gas Flow Proportional Counter Model 8600A-LB XIA "UltraLo-1800" The alpha dose using this method is calculated by measuring the area of ​​1000cm 2 From 4000cm 2 It refers to the alpha dose calculated from the values ​​counted for 72 to 100 hours.

[0078] <Powder mixture> The compound powder according to any of the above embodiments may be combined with silica powder or other thermally conductive powders to form a powder mixture.

[0079] The silica powder that can be used to form the powder mixture is not particularly limited as long as it is a particulate material containing silica. The silica powder may be silica. As the 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 a core particle such as a resin particle or a metal particle, or a hollow silica powder. The particle shape of the silica powder or other thermally conductive powder is preferably substantially spherical from the viewpoint of flowability when mixed with a matrix material such as a resin. The volume cumulative particle size D of the silica powder or other thermally conductive powder at 50% cumulative volume as measured by a laser diffraction / scattering particle size distribution measurement method is 50 From the same viewpoint as above, 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.

[0080] The thermally conductive powder other than silica powder is not particularly limited and may be any known one. Examples of other thermally conductive powders include carbon compounds such as graphite and diamond; metal oxides such as aluminum oxide, magnesium oxide, beryllium oxide, titanium oxide, zirconium oxide, and zinc oxide (other than the Ca-containing composite oxides that are the above-mentioned compound powders); 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 baked products such as acrylonitrile polymer baked products, furan resin baked products, cresol resin baked products, polyvinyl chloride baked products, sugar baked products, and charcoal baked products; composite ferrites of ferrite and Zn ferrite; Fe-Al-Si ternary alloys; metal powders, or mixtures thereof.

[0081] The mass ratio of the compound powder to the silica powder or other thermally conductive powder in the powder mixture may be, for example, between 1:99 and 100:0, or between 20:80 and 100:0, preferably between 30:70 and 95:5, more preferably between 40:60 and 90:10, and even more preferably between 50:50 and 80:20 or between 60:40 and 80:20, from the viewpoint of balancing the effective expression of negative thermal expansion properties and the reduction of manufacturing costs.

[0082] In one embodiment, two or more powders of negative thermal expansion materials including the above-mentioned compound powder may be mixed to form a powder mixture further including a silica-containing powder or other thermally conductive powder. In a further embodiment, a powder mixture can be formed containing the above-mentioned compound powder and another negative thermal expansion material, wherein the other negative thermal expansion material has a temperature range in which the linear expansion coefficient (α) is less than 0 ppm / K at least in the temperature range of 0°C or higher and 70°C or lower. In one modified embodiment, a mixed material can be formed by mixing two or more negative thermal expansion materials, and the mixed material can have a temperature range in which the linear expansion coefficient (α) is less than 0 ppm / K at least in the temperature range of 0°C or higher and 70°C or lower. In addition, in a related modified embodiment, a mixed material can be formed that is a powder mixture of two or more negative thermal expansion materials, each having a temperature range in which the linear expansion coefficient (α) is less than 0 ppm / K at least in the temperature range of 0°C or higher and 70°C or lower, and that is a mixture of two or more negative thermal expansion material powders, each having a temperature range in which the linear expansion coefficient (α) is less than 0 ppm / K at least in the temperature range of 0°C or higher and 70°C or lower.

[0083] <Electronic component manufacturing method> For example, electronic components can be manufactured by (1) applying a resin composition containing a compound powder and a resin component according to any of the above-described embodiments to a first member, (2) applying a second member to the resin composition simultaneously with or after applying the resin composition to the first member, thereby obtaining a member combination in which the resin composition is sealed between the first and second members, and (3) simultaneously with or after obtaining the member combination, pressing the member combination under heat to seal the space between the first and second members with the resin composition. In the production of such electronic components, an encapsulant containing a resin composition containing a compound powder and a resin component can be used for sealing the electronic components. Furthermore, in the production of such electronic components, an encapsulant containing a resin composition containing a compound powder and a resin component can be used as an underfill for sealing the electronic components. That is, in the present application, an encapsulant for electronic components is provided that contains (or is formed from) a resin composition containing a compound powder and a resin component; and an underfill for electronic component sealing that contains (or is formed from) a resin composition containing a compound powder and a resin component is also provided. The underfill for electronic component sealing can be rephrased as an underfill encapsulant for electronic components.

[0084] The resin composition applied to the first member can be appropriately selected from resin compositions containing compound powder and resin components. The first and second members are not particularly limited as long as the resin composition can be applied to their surfaces and they can withstand pressure bonding under heat. The materials constituting the first and second members may be the same or different. Specific examples of the first member and the second member include electronic members such as a silicon wafer, a metal plate, a glass plate, a heat-resistant resin plate, a semiconductor chip, etc. 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.

[0085] In a preferred embodiment, a resin composition containing a compound powder and a resin component is applied as an underfill sealant to a circuit board, which is a silicon wafer, as a first component. A semiconductor chip, which is a second component, is placed on top of the resin composition underfill sealant. Then, by heating and pressing, the resin composition is cured and electrodes formed on the semiconductor chip are connected to electrodes formed on the circuit board simultaneously, thereby sealing the semiconductor chip and the circuit board with the resin composition, thereby producing an electronic component (semiconductor device). The heating temperature for the heating and pressing is not particularly limited, as long as the resin constituting the resin composition is maintained in a molten state. The pressure applied for the heating and pressing is not particularly limited, as long as the connection between the semiconductor chip and the circuit board can be reliably achieved. This type of thermocompression bonding technique is called the NCP (Non Conductive Paste) method. The NCP method advantageously shortens the process and curing time, thereby providing a low-cost, low-energy pre-applied flip-chip bonding process. Furthermore, this thermocompression bonding technique can suppress the occurrence of unfilled portions (voids) in the encapsulant and achieve a sufficient filling rate, even if the compound powder contained in the resin composition does not have high sphericity.

[0086] In another preferred embodiment, a film-like semiconductor encapsulant formed from a resin composition containing a compound powder and a resin component is laminated onto a semiconductor chip (a first component), and then the film-like semiconductor encapsulant is pressed against a circuit board (a second component) under heat to connect electrodes formed on the semiconductor chip and electrodes formed on the circuit board. The resin composition is then heat-cured to produce an electronic component (semiconductor device) in which a semiconductor chip is mounted on a circuit board. As with the above-described embodiment, the heating temperature for the pressure-bonding under heat is not particularly limited, as long as the resin constituting the resin composition is maintained in a molten state. The pressure applied for the pressure-bonding under heat is not particularly limited, as long as the connection between the semiconductor chip and the circuit board can be reliably achieved. This type of thermocompression bonding method is called the NCF (Non Conductive Film) method. The NCF method has the advantage of being able to achieve good bonding by ensuring reliable sealing with reduced void generation, even when the gap between the semiconductor chip and the substrate is narrow. Furthermore, like the NCP method, this thermocompression bonding method can also suppress the generation of unfilled portions (voids) in the encapsulant and achieve a sufficient filling rate, even when the compound powder contained in the resin composition does not have high sphericity.

[0087] In another preferred embodiment, instead of the NCP or NCF method described above, electronic components (semiconductor devices) can be manufactured using the ACP (Anisotropic Conductive Paste) method or the ACF (Anisotropic Conductive Film) method, in which predetermined conductive particles are mixed with a resin composition containing a compound powder and a resin component to form an anisotropic conductive adhesive, and a similar process is then performed. Examples of conductive particles include, but are not limited to, metal particles (e.g., nickel or a gold-coated nickel composite), metal-plated (e.g., gold-plated) resin particles such as acrylic resin, and particles having an insulating coating thereon that breaks or melts when exposed to heat or pressure. The average size of the conductive particles can be, for example, 1 μm or more and 50 μm or less. As with the NCP or NCF method, this thermocompression bonding technique can also suppress the occurrence of unfilled portions (voids) in the encapsulant and achieve a sufficient filling rate, even if the sphericity (sphericity) of the compound powder contained in the resin composition is not high. [Example]

[0088] The present invention will be described in more detail below with reference to examples. These examples should not be construed as limiting the present invention in any way, but are merely illustrative.

[0089] Example 1 (1) Preparation of substrate particles containing P, Zn, and Mg By dry synthesis, Zn 1.6 Mg 0.4 A ceramic powder of base particles represented by P2O7 was prepared. Specifically, 19.629 g of ZnO, 2.472 g of MgO, and 34.619 g of (NH4)H2PO4, weighed in the stoichiometric ratio, were mixed in a mortar in the air. The mixed powder was then fired in an electric furnace at 250°C for 5 hours in the air. The resulting fired material was then manually crushed in the mortar in the air, remixed, and fired in an electric furnace at 350°C for 10 hours in the air. The resulting fired material was then crushed in a force mill for approximately 30 seconds, remixed, and fired in an electric furnace at 900°C for 10 hours in the air. This fired material was then crushed in a force mill for approximately 30 seconds. The crushed powder was then placed in a plastic container with 1.0 mm diameter zirconia beads and pure water. The plastic container was then placed in a rocking shaker (manufactured by Seiwa Giken Co., Ltd.) and shaken for 1 hour using the rocking shaker. The zirconia beads were then separated using a mesh, followed by solid-liquid separation using a small centrifuge (Eppendorf-Himac Technologies Co., Ltd.: CT6E). The solids were then dried at 110°C using a dryer to obtain powder. This powder was then mixed with pure water, allowed to settle, and washed by decantation. The supernatant was repeatedly washed until its electrical conductivity (measured in accordance with JIS K0130:2008 using the same method as described below) reached ≦20 μS / cm, after which the same solid-liquid separation was carried out again. The particles after solid-liquid separation were dried at approximately 110°C for 3 hours and then crushed in a force mill for approximately 30 seconds to obtain base particles. The X-ray diffraction patterns of the base particles were evaluated using powder X-ray diffraction (XRD) (measurement temperature 295 K, CuKα characteristic X-ray: wavelength λ = 0.15418 nm) and synchrotron radiation temperature change X-ray diffraction (wavelength λ = 0.06521 nm), and Zn 1.6 Mg 0.4 It was confirmed that a crystal structure of P2O7 was formed. The average particle diameter of the obtained base particles (volume cumulative particle diameter D at 50% cumulative volume measured by laser diffraction scattering particle size distribution measurement method)50 ) was approximately 5 μm.

[0090] (2) Formation of a coating layer made of oxides containing Ca and P A quantity of 0.3 g of Ca(OH)2 was added to the substrate particles (Zn 1.6 Mg 0.4 A dispersion was obtained by ultrasonically dispersing 30 g of the ceramic powder (P2O7) together with 0.5 g of a polycarboxylic acid-based dispersant "SN Dispersant 5468" (manufactured by San Nopco Co., Ltd.), which was approximately 1.7 mass % of the base particles, in 200 g of pure water. 30 g of the base particles was mixed with this dispersion. In the resulting mixture, the amount of Ca(OH)2 relative to the base particles was 1 mass %. This mixture was mechanically stirred thoroughly for approximately 1 hour to obtain a raw material dispersion. This raw material dispersion was subjected to solid-liquid separation by filtration and dried at 150 °C for 2 hours to obtain a raw material for firing. This raw material for firing was then fired at 800 °C for 10 hours under atmospheric pressure. This fired product was then mixed with pure water, stirred with a stirrer, and solid-liquid separation was performed by removing the supernatant liquid. Further washing was performed by adding water and repeating this solid-liquid separation five times. The mixture was then poured into an evaporating dish, and the solids were dried by heating in a hot air dryer at 110 °C. As a result, a compound powder was obtained, which was a composite containing base particles and a Ca-containing coating layer on the surface of the base particles.

[0091] Example 2 The above base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of P2O7 (ceramic powder) was changed to 0.6 g (2 mass%) to obtain a raw material dispersion.

[0092] Example 3 The above base particles (Zn 1.6 Mg 0.4A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of the ceramic powder represented by P2O7 was changed to 0.75 g (2.5 mass%) to obtain a raw material dispersion, and the firing raw material was fired at 650°C under atmospheric pressure for 10 hours.

[0093] Example 4 The above base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of P2O7 (ceramic powder) was changed to 1.5 g (5 mass%) to obtain a raw material dispersion.

[0094] Example 5 The above base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of the ceramic powder represented by P2O7 was changed to 3 g (10 mass %) to obtain a raw material dispersion, and the raw material for firing was fired at 500°C under atmospheric pressure for 10 hours.

[0095] Example 6 The above base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of P2O7 (ceramic powder) was changed to 3 g (10 mass%) to obtain a raw material dispersion.

[0096] Example 7 The above base particles (Zn 1.6 Mg 0.4A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of the ceramic powder represented by P2O7 was changed to 3 g (10 mass%) to obtain a raw material dispersion, and that the raw material dispersion was subjected to solid-liquid separation by filtration and dried at 150°C for 2 hours, without being fired, washed, or dried.

[0097] Example 8 The above base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of P2O7 (ceramic powder) was changed to 6 g (20 mass%) to obtain a raw material dispersion.

[0098] Example 9 The above base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of P2O7 (ceramic powder) was changed to 6 g (20 mass%) to obtain a raw material dispersion, and the firing raw material was fired at 600°C under atmospheric pressure for 10 hours.

[0099] Example 10 The above base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of Ca(OH)2 relative to the amount of P2O7 (ceramic powder) was changed to 6 g (20 mass%) to obtain a raw material dispersion, and the firing raw material was fired at 700°C under atmospheric pressure for 10 hours.

[0100] Example 11 As the Ca-containing compound for forming the coating layer, Ca(CH3COO)2 was used instead of Ca(OH)2, and the above-mentioned base particles (Zn 1.6 Mg0.4 A compound powder was obtained as a composite containing base particles and a Ca-containing coating layer on the surface thereof in the same manner as in Example 1, except that the amount of Ca(CHCOO) was adjusted to 3 g (10 mass %) relative to the amount of Ca(CHCOO) relative to the amount of P2O7 (ceramic powder), and the raw material dispersion was obtained, and the firing raw material was fired at 500°C for 10 hours under atmospheric pressure.

[0101] Example 12 As the Ca-containing compound for forming the coating layer, Ca(CH3COO)2 was used instead of Ca(OH)2, and the above-mentioned base particles (Zn 1.6 Mg 0.4 A compound powder was obtained as a composite containing base particles and a Ca-containing coating layer on the surface thereof in the same manner as in Example 1, except that the amount of Ca(CHCOO) was adjusted to 3 g (10 mass %) relative to the amount of Ca(CHCOO) relative to the amount of P2O7 (ceramic powder), and the raw material dispersion was obtained, and the firing raw material was fired at 650°C for 10 hours under atmospheric pressure.

[0102] Example 13 As the Ca-containing compound for forming the coating layer, Ca(CH3COO)2 was used instead of Ca(OH)2, and the above-mentioned base particles (Zn 1.6 Mg 0.4 A compound powder was obtained as a composite containing base particles and a Ca-containing coating layer on the surface thereof in the same manner as in Example 1, except that the amount of Ca(CHCOO) was adjusted to 6 g (20 mass %) relative to the amount of Ca(CHCOO) relative to the amount of P2O7 (ceramic powder), and the raw material dispersion was obtained, and the firing raw material was fired at 500°C for 10 hours under atmospheric pressure.

[0103] Example 14 As the Ca-containing compound for forming the coating layer, Ca(CH3COO)2 was used instead of Ca(OH)2, and the above-mentioned base particles (Zn 1.6 Mg 0.4A compound powder was obtained as a composite containing base particles and a Ca-containing coating layer on the surface thereof in the same manner as in Example 1, except that the amount of Ca(CHCOO) was adjusted to 9 g (30 mass %) relative to the amount of Ca(CHCOO) relative to the amount of P2O7 (ceramic powder), and the raw material dispersion was obtained, and the firing raw material was fired at 500°C for 10 hours under atmospheric pressure.

[0104] Example 15 Egg shells (main component: calcium carbonate) with a thin egg membrane (main component: protein) attached to the surface were collected and coarsely crushed in a mortar and pestle, and then further crushed in a food mixer. The crushed egg shells were passed through a 1 mm mesh sieve to separate the egg membrane (main component: protein) attached to the surface from the shell. The egg shells (main component: calcium carbonate) remaining below the sieve from which the egg membrane was separated were dissolved in acetic acid to form a calcium acetate solution. This calcium acetate solution was used to prepare the base particles (Zn 1.6 Mg 0.4 A coating was applied to a base particle (ceramic powder represented by P2O7). The Ca concentration in the calcium acetate solution was adjusted to be equivalent to the Ca content of Ca(CH3COO)2 relative to the base particle in Example 11. The firing raw material was fired at 500°C for 10 hours under atmospheric pressure. Aside from these operations, a compound powder was obtained, which was a composite comprising base particles and a Ca-containing coating layer on the surface of the base particle, in the same manner as in Example 1.

[0105] Example 16 As the Ca-containing compound for forming the coating layer, Ca(CH3COO)2 was used instead of Ca(OH)2, and the above-mentioned base particles (Zn 1.6 Mg 0.4 A compound powder was obtained as a composite containing base particles and a Ca-containing coating layer on the surface thereof in the same manner as in Example 1, except that the amount of Ca(CHCOO) was adjusted to 3 g (10 mass %) relative to the amount of Ca(CHCOO) relative to the amount of P2O7 (ceramic powder), and the raw material dispersion was obtained, and the firing raw material was heat-treated at 80°C under atmospheric pressure for 10 hours.

[0106] Example 17 As the Ca-containing compound for forming the coating layer, CaMoO4 was used instead of Ca(OH)2, and the above-mentioned base particles (Zn 1.6 Mg 0.4 A compound powder was obtained in the same manner as in Example 1, except that the amount of CaMoO4 relative to the amount of CaMoO4 (ceramic powder represented by P2O7) was adjusted to 1.5 g (5 mass %) to obtain a raw material dispersion.

[0107] Comparative Example 1 The base particles (Zn 1.6 Mg 0.4 In the preparation of the ceramic powder represented by P2O7, base particles were formed without washing with decantation and the accompanying solid-liquid separation. These unwashed base particles are referred to as Comparative Example 1.

[0108] Comparative Example 2 The above-mentioned base particles (Zn) that have not been subjected to a coating layer forming treatment and have been washed 1.6 Mg 0.4 A ceramic powder represented by P2O7 was prepared as a comparison.

[0109] Measurement methods for various physical properties Volume cumulative particle size D measured by laser diffraction scattering particle size distribution measurement method 10 , D 50 and D 90 Measurement of The samples obtained in each example and comparative example were placed in pure water and dispersed by ultrasonic irradiation (40 W, 3 minutes), and then the volume cumulative particle size D at 10% cumulative volume by volume was measured using a particle size distribution measuring device (Microtrac (product name) MT-3300EXII (model number) manufactured by Microtrac Bell Co., Ltd.). 10 , cumulative particle size at 50% by volume D 50 , and the volume cumulative particle size at 90% by volume of the cumulative volume D 90 was measured.

[0110] -Volume resistivity measurement The samples obtained in each example and comparative example were compressed at a pressure of 63 MPa using a powder resistivity measurement system "MCP-PD51" manufactured by Mitsubishi Chemical Analytech Co., Ltd., and the volume resistivity was measured using the four-terminal method. For samples that exceeded the measurement limit of this device, pellets were separately compressed at a pressure of 63 MPa and measured using a high resistance meter "Hiresta UX / MCP-HT800" manufactured by Mitsubishi Chemical Analytech Co., Ltd.

[0111] BET specific surface area measurement Using a specific surface area measuring device (Mountec Co., Ltd.'s "Macsorb (HM model-1201)"), the BET specific surface area of ​​the samples obtained in each example and comparative example was measured in accordance with JIS Z 8830:2013 (Method for measuring the specific surface area of ​​powders (solids) by gas adsorption). A mixed gas of helium as the carrier gas and nitrogen as the adsorbate gas was used. The degassing conditions were 300°C x 10 minutes.

[0112] ·Composition analysis The compositions (atomic ratios) of the samples obtained in each of the examples and comparative examples were analyzed using ICP-OES (Inductivity Coupled Plasma Optical Emission Spectrometry). The ICP-OES device used was an Agilient 5110 (manufactured by Agilient Technologies).

[0113] XRD peak observation and peak intensity ratio measurement The samples obtained in each example and comparative example were scanned at room temperature using a powder X-ray diffractometer ("MiniFlex2" manufactured by Rigaku Corporation) with Cu-Kα radiation under the conditions of a tube voltage of 30 kV, a tube current of 15 mA, a scanning speed of 5° / min, and a scanning angle 2θ of 5° to 80°, to observe peaks. Other operating conditions for powder X-ray diffraction were as follows: ·Slit: DS-SS; 1.25 degree, RS; 0.3mm Monochromator graphite Step: 0.02° Counting method: Constant counting method X-ray analysis software: PDXL2 Version 2.9.1.0 Using a powder X-ray diffractometer under the above conditions, the XRD peak intensity ratio (-6 0 2) / (0 2 2) and the XRD peak intensity ratio (2 0 -1) / (0 2 2) were measured at 30°C, 50°C, and 100°C, respectively. where: The "(-6 0 2)" peak intensity refers to the (-6 0 2) plane peak intensity appearing at a diffraction angle 2θ of 29.3 to 29.55°. The "(0 2 2)" peak intensity refers to the (0 2 2) plane peak intensity appearing at a diffraction angle 2θ = 29.6 to 29.7°. The "(2 0 -1)" peak intensity refers to the (2 0 -1) plane peak intensity appearing at 30.0 to 30.2°.

[0114] Measurement method for dimensional change ratio (ΔL / L) of epoxy resin composition using TMA 3.90 g of the compound powder of each Example or the base particle of each Comparative Example, 1.28 g of the epoxy resin main component, 0.23 g of diluent, and 0.55 g of curing agent described below were mixed (rotation speed: 2000 rpm, time: 30 seconds) and degassed (rotation speed: 2200 rpm, time: 30 seconds or more) using a kneader (Awatori Rentaro ARE-310, manufactured by THINKY). The resulting resin composition was placed in a cylindrical container with a diameter of 10 mm and then degassed in a vacuum container. The defoamed resin composition was cured by heating in a dryer at 80°C for 1 hour and then at 150°C for 3 hours. The cured resin composition was cut into pieces measuring 10 mm (diameter) x 5 mm (height) and processed into tablets (pellets). The dimensional change ratio (ΔL / L) of the resin composition processed into tablets was measured. Epoxy resin base: JER-807, JER-806H, JER-806 (Mitsubishi Chemical Corporation) Diluent: Mitsubishi Chemical Corporation YED216M Hardener: Mitsubishi Chemical jER Cure 113

[0115] The measurement conditions for the dimensional change ratio (ΔL / L) by TMA were as follows: Instrument: TA7000 (Hitachi High-Technologies thermomechanical analyzer TMA7000 series) First cycle: The sample was heated from 30°C to 150°C at a rate of 6°C / min in air while applying a load of 100mN. The sample was then cooled to room temperature while still under load. Second cycle: The sample was heated from 30°C to 150°C at a rate of 1°C / min in an air atmosphere.

[0116] - Measurement of the amount of eluted ions, pH and conductivity of the test solution through ion elution tests A 2 g sample of powder of the substance to be measured and 40 ml of pure water were placed in a sealed pressure vessel (a 100 ml autoclave made of polytetrafluoroethylene resin). After manual shaking for 1 minute, the sealed pressure vessel was heated at 121 °C for 20 hours. After cooling to room temperature, the sealed pressure vessel was opened to remove the treated liquid. The solid-liquid separation was performed using a 0.45 μm membrane filter. The filtrate, from which the insoluble matter had been removed, was used as the test solution for the ion elution test. The amount of eluted ions in this test solution was measured using an ICP-OES instrument "Agilient 5110" (manufactured by Agilient Technologies), and the pH and conductivity of the test solution were measured using a HORIBA "LAQUA" model "D-200-2."

[0117] XRD peaks of Examples 1 to 2, 4, 6, and 8 The compound powders obtained in Examples 1-2, 4, 6, and 8 were scanned using an X-ray diffractometer, and peaks were observed at 2θ = approximately 22.2-22.3°, 22.6-22.7°, 23.1-23.2°, 23.5°, 24.0°, and 25.0°, respectively. As an average trend, the peak intensity generally increased as the amount of Ca(OH)2 during coating layer formation increased in the order of Examples 1-2, 4, 6, and 8. These peaks are presumed to be derived from the Zn-Ca-PO metal compound, and it is understood that a thicker coating layer was formed as the amount of Ca(OH)2 increased. In addition, for all of the compound powders obtained in Examples 1 to 2, 4, 6, and 8, the base particle (Zn 1.6 Mg 0.4 A peak thought to be derived from the sintered ceramic represented by P2O7 was observed. Therefore, it was confirmed that the crystalline structure of the base particles was maintained even after the Ca-containing coating layer was formed on the base particles. For each of the compound powders obtained in Examples 1-2, 4, 6, and 8, a peak presumably derived from a Zn-PO metal compound was also observed near 25.5-26.5°. For further verification, EDX line analysis was performed on the compound powders obtained in Examples 1-2, 4, 6, and 8. In this case, the EDX line analysis conditions were set to Vacc. = 5 kV and Ipor. = 200 pA, which make penetration difficult, so that only surface elements could be observed. As a result, Zn, Mg, O, and P were observed on the surface of the compound powder, along with Ca.

[0118] Powder properties of compound powders of Examples 1 to 17 and base particles of Comparative Examples 1 and 2 The volume resistivity, volume cumulative particle diameter D measured for the compound powders of Examples 1 to 17 and the base particles of Comparative Examples 1 and 2 10 , D 50 , D 90 , and (D 90 -D 10 ) / D 50 The BET specific surface area and the composition analysis results of each element are shown in Table 1 below. The results shown in Table 1 show that the compound powders of Examples 1 to 17 had increased volume resistivity compared to Comparative Examples 1 and 2, had no significant differences in particle size distribution, and had no significant changes in composition except for Ca. Furthermore, the compound powders of Examples 1 to 2, 4, and 6 had significantly lower BET specific surface areas compared to Comparative Examples 1 and 2.

[0119] [Table 1]

[0120] XRD peak intensity ratios of compound powders of Examples 1 to 17 and base particles of Comparative Examples 1 and 2 The XRD peak intensity ratios (-6 0 2) / (0 2 2) and (2 0 -1) / (0 2 2) measured for the compound powders of Examples 1 to 17 and the base particles of Comparative Examples 1 and 2 at 30°C, 50°C, and 100°C, respectively, are shown in Table 2 below. The results shown in Table 2 show that the compound powders of Examples 1 to 17 did not show a significant difference in the progress of the change in crystal structure due to temperature increase compared to Comparative Examples 1 and 2.

[0121] [Table 2]

[0122] Dimensional change ratio (ΔL / L) of the compound powders of Examples 1 to 17 and the resin pellets of the base particles of Comparative Examples 1 and 2, and the amount of eluted ions, pH, and conductivity of the test solution in the ion elution test The dimensional change ratios (ΔL / L) at 30°C, 50°C, and 70°C measured for the compound powders of Examples 1 to 17 and the resin pellets of the base particles of Comparative Examples 1 and 2, as well as the amount of eluted ions, pH, and conductivity of the test solution in the ion elution test measured for the compound powders of Examples 1 to 17 and the base particles of Comparative Examples 1 and 2, are shown in Table 3 below. The results shown in Table 3 show that the compound powders of Examples 1 to 17 either provided higher negative thermal expansion characteristics for the resin pellets depending on the temperature, or minimized the change to positive thermal expansion characteristics, compared to Comparative Examples 1 and 2. The results in the same table also show that the compound powders of Examples 1 to 17 significantly suppressed the elution of Mg, P, and Zn compared to Comparative Examples 1 and 2, resulting in a reduction in electrical conductivity.

[0123] [Table 3] [Industrial Applicability]

[0124] The novel compound powder according to the present invention is advantageous in that it exhibits negative thermal expansion properties in a lower temperature range and is preferably used as a negative thermal expansion material with a higher thermal shrinkage rate, thereby further reducing the possibility of misalignment, interfacial peeling, disconnection, etc., due to differences in the thermal expansion rates between materials. This makes it possible to reduce product defects during the manufacture of highly advanced electronic and optical devices, fuel cells, sensors, etc., as well as damage and deterioration during repeated use, and also reduces waste and energy costs during manufacture and use. Due to these points, the compound powder of the present invention enables sustainable management and efficient use of natural resources and promotes decarbonization (carbon neutrality) in the production and use of compound powders and electronic devices, etc.

Claims

1. A compound powder containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, The compound powder is a base particle formed from a compound containing elements A and O (oxygen); and a composite including a coating layer formed from a metal compound containing Ca and element A, the coating layer coating the surface of the base particle, The linear expansion coefficient (α) is less than 0 ppm / K in at least a temperature range of 0°C or more and 70°C or less, or the dimensional change ratio (ΔL / L) is less than 0 in at least a temperature range of 0°C or more and 70°C or less, or the linear expansion coefficient (α) is less than -0.5 × 10 in at least a temperature range of 30°C or more and 70°C or less. －３ Has a dimensional change ratio (ΔL / L) that is equal to or less than Compound powder.

2. 2 g of a sample of the compound powder and 40 ml of pure water are placed in a pressure-resistant container at room temperature, the container is sealed, and the container is manually shaken for 1 minute. After that, the sealed pressure-resistant container is heated at 121°C for 20 hours, and then allowed to cool to room temperature. The sealed pressure-resistant container is opened to remove the treated liquid, and the filtrate is subjected to solid-liquid separation using a 0.45 μm membrane filter. Insoluble matter is removed from the filtrate, and the filtrate is used as a test liquid for an ion elution test. The amount of at least one ion of the element A eluted into the test liquid is 3000 ppm by mass or less per 1 g of the sample. The compound powder according to claim 1 .

3. The compound powder according to claim 2 , wherein the amount of ions of the element A eluted in the ion elution test is 1000 ppm by mass or less per 1 g of the sample.

4. The compound powder according to claim 2 , wherein the amount of P ions eluted in the ion elution test is 3000 ppm by mass or less per 1 g of the sample.

5. (i) the amount of Zn ions eluted in the ion elution test is 3000 mass ppm or less per 1 g of the sample; (ii) the amount of Cu ions eluted in the ion elution test is 3000 mass ppm or less per 1 g of the sample; (iii) the amount of Mg ions eluted in the ion elution test is 3000 mass ppm or less per 1 g of the sample; and (iv) The amount of V ions eluted in the ion elution test is 3000 mass ppm or less per 1 g of the sample. The compound powder according to claim 2, which satisfies any one or more of the above.

6. The base particles are of the general formula Zn ２－ｘ Mg ｘ P ２ O ７ 3. The compound powder according to claim 1, comprising an oxide represented by the formula (wherein 0.1≦x≦0.8 is satisfied).

7. 3. The compound powder according to claim 1, wherein the metal compound containing Ca and the element A that coats the surface of the base particle comprises a metal compound containing Ca, the element A, and O (oxygen).

8. Volume resistivity at 25°C is 1.0 x 10 ９ The compound powder according to claim 1 or 2, having a resistivity of Ω·cm or more.

9. the element A includes P, The metal compound containing Ca and element A that coats the surface of the base particle includes an oxide of Ca and P. The compound powder according to claim 1 or 2.

10. The compound containing the element A and O (oxygen) is represented by the general formula (1): ２－ｘ T ｘ P ２－ｙ A ｙ O ７±δ 3. The compound powder according to claim 1, comprising an oxide represented by the formula (1), wherein T contains 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 contains 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 so as to satisfy a charge neutrality condition, excluding (x, y)=(0,0) and (0,2).

11. A resin composition comprising the compound powder according to claim 1 or 2 and a resin component.

12. The resin composition according to claim 11, further comprising a curing agent.

13. Alpha radiation dose is 0.0200 cph / cm ２ The resin composition according to claim 11, wherein:

14. A powder mixture comprising a powder of the compound according to claim 1 or 2 and a silica powder or other thermally conductive powder.

15. A sealing material for electronic components, comprising the resin composition according to claim 11.

16. An underfill for sealing electronic components, comprising the resin composition according to claim 11.

17. 1. A method for producing a compound powder containing at least one element A selected from the group consisting of P, Zn, Cu, Mg, and V, comprising: providing a substrate particle formed from a compound containing the elements A and O (oxygen); and The method includes a step of applying a coating medium containing a Ca-containing compound onto the surface of the base particle, and then firing the coating medium to obtain a composite including a coating layer formed from a metal compound containing Ca and element A, The compound powder has a temperature range in which the linear expansion coefficient (α) is less than 0 ppm / K at least in the temperature range of 0° C. or more and 70° C. or less, or has a temperature range in which the dimensional change ratio (ΔL / L) is less than 0 at least in the temperature range of 0° C. or more and 70° C. or less, or has a temperature range in which the dimensional change ratio (ΔL / L) is less than −0.5×10 at least in the temperature range of 30° C. or more and 70° C. or less. －３ Has a dimensional change ratio (ΔL / L) that is equal to or less than A method for producing the compound powder.

18. 2 g of a sample of the compound powder and 40 ml of pure water are placed in a pressure-resistant container at room temperature, the container is sealed, and the container is manually shaken for 1 minute. After that, the sealed pressure-resistant container is heated at 121°C for 20 hours, and then allowed to cool to room temperature. The sealed pressure-resistant container is opened to remove the treated liquid, and the filtrate is subjected to solid-liquid separation using a 0.45 μm membrane filter. Insoluble matter is removed from the filtrate, and the filtrate is used as a test liquid for an ion elution test. The amount of at least one ion of the element A eluted into the test liquid is 3000 ppm by mass or less per 1 g of the sample.

18. The method of claim 17.

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