TW201731764A - Negative thermal expansion material and composite material including same - Google Patents

Abstract

To provide a negative thermal expansion material that has excellent dispersibility and filling characteristics with respect to a positive thermal expansion material. This negative thermal expansion material comprises spherical zirconium tungsten phosphate that has a BET specific surface area of 2 m2/g or less. The sphericity of the negative thermal expansion material is ideally 0.90-1. The negative thermal expansion material ideally contains at least Mg and/or V as subcomponent elements. The subcomponent element content of the negative thermal expansion material is ideally 0.1-3 mass%. The average particle size of the negative thermal expansion material is ideally 1-50 [mu]m.

Description

Negative thermal expansion material and composite material containing the same

The present invention relates to a negative thermal expansion material that shrinks as the temperature rises and a composite material containing the same.

If the temperature rises, many substances will increase in length or volume as the heat expands. On the other hand, a material which exhibits a negative thermal expansion when the temperature is increased (hereinafter sometimes referred to as a "negative thermal expansion material") is also known. It is known that materials exhibiting negative thermal expansion can be used with other materials to inhibit changes in the thermal expansion of the material caused by temperature changes.

Materials exhibiting negative thermal expansion are known, for example, β-eucryptite, zirconium tungstate (ZrW ₂ O ₈ ), zirconium tungstate phosphate (Zr ₂ WO ₄ (PO ₄ ) ₂ ), Zn _x Cd _1-x (CN) ₂ , manganese nitride, bismuth nickel, iron oxide, and the like.

The linear expansion coefficient of zirconium tungstate phosphate is -3.4 ppm / ° C to -3.0 ppm / ° C in the temperature range of 0 ° C to 400 ° C, and can be a material having a large thermal expansion property and exhibiting a positive thermal expansion (hereinafter Also known as "positive thermal expansion material") and used to make low thermal expansion materials.

As a method for producing zirconium tungstate phosphate, for example, Patent Document 1 below proposes a method in which a reaction accelerator such as zirconium phosphate, tungsten oxide or MgO is mixed in a wet ball mill, and the obtained mixture is at 1200 ° C. Calcination is carried out. Patent Document 2 listed below proposes a method in which a phosphorus source such as ammonium phosphate or a tungsten source such as ammonium tungstate or a zirconium source such as zirconium chloride is wet-mixed, followed by calcination. Non-Patent Document 1 below proposes a method of calcining a mixture containing zirconia, tungsten oxide, and ammonium dihydrogen phosphate at 1200 ° C. However, the particle shape of zirconium phosphotungstate produced by the patent document 1 and the patent document 2 and the non-patent document 1 is a fracture shape, and if it is known by the inventors, the spherical shape is not reported. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-35840, the third and the s. [Patent Document 2] Japanese Patent Laid-Open Publication No. 2015-10006, paragraph 0023, paragraph 0025. [Non-patent literature]

[Non-Patent Document 1] "Materials Research Bulletin", 44 (2009), pp. 2045-2049.

[Problems to be Solved by the Invention] As a negative thermal expansion material, zirconium phosphotungstate is considered to be a member for performing ultra-precision machining.

In general, the negative thermal expansion material is used in a positive thermal expansion material such as a metal, an alloy, a glass, a ceramic, a resin, or a rubber, but it is desirable to develop a negative thermal expansion material which is more excellent in dispersibility and filling characteristics in the positive thermal expansion material. In particular, when zirconium phosphotungstic acid is used as a negative thermal expansion material and is mixed in a large amount in a resin, the viscosity is likely to be improved during molding of the resin. Therefore, it is difficult to mix a sufficient amount of zirconium phosphate zirconate in the resin, and it is difficult to suppress thermal expansion of the resin. The problem.

Accordingly, an object of the present invention is to provide a negative thermal expansion material having excellent dispersibility and filling characteristics for a positive thermal expansion material and a composite material containing the same. [Means for solving the problem]

The present inventors have conducted intensive studies in view of the above facts, and as a result, have found that spherical zirconium phosphotungstate is obtained by the following steps: Step A, for a zirconium compound containing zirconium hydroxide and zirconium carbonate, The slurry of the phosphoric acid and the tungsten compound is subjected to heat treatment; in the step B, the slurry after the step A is subjected to wet pulverization treatment by a media mill; and the step C, followed by spray drying the slurry after the step B Treating to obtain a spherical reaction precursor; the D step, and then calcining the spherical reaction precursor; in addition, the spherical zirconium tungstate phosphate has excellent negative thermal expansion; further, in the spherical shape In the case of zirconium tungstate phosphate, when the specific surface area of the Brunauer-Emmett-Teller (BET) specific surface area is blended in the resin, the viscosity at the time of molding the resin is also suppressed to a low value, and it can be used in the resin. A sufficient amount of zirconium tungstate phosphate or the like is prepared, and the filling property is excellent and the dispersibility is also excellent. Thus, the present invention has been completed.

That is, the first invention to be provided by the present invention is a negative thermal expansion material comprising spherical zirconium phosphotungstate having a BET specific surface area of 2 m ² /g or less.

Further, the second invention to be provided by the present invention is a composite material comprising the negative thermal expansion material of the first invention and the positive thermal expansion material. [Effects of the Invention]

According to the present invention, it is possible to provide a negative thermal expansion material comprising zirconium phosphate zirconate having excellent dispersibility and filling characteristics for a positive thermal expansion material.

Hereinafter, the present invention will be described based on preferred embodiments of the present invention. The negative thermal expansion material of the present invention is a spherical zirconium phosphotungstate containing a BET specific surface area of 2 m ² /g or less, and the negative thermal expansion material having the above configuration has excellent dispersibility and filling characteristics for a positive thermal expansion material. .

The present inventors have found that the zirconium phosphotungstate having the above configuration can reduce the interaction between the resin and the negative thermal expansion material when the resin is kneaded, for example, when compared with the conventionally used zirconium phosphotungstate. The viscosity of the composition at the time of molding.

Further, the conventional crushed zirconium phosphotungstate has a portion where the particle strength is weak due to the particle shape. Therefore, for example, when a composite material of glass powder and zirconium tungstate is used as a sealing material, when glass powder and glass powder are used, In the mixed treatment of zirconium tungstate phosphate, since the hard glass powder strongly collides with the zirconium tungstate phosphate particles, the particles are broken from the fragile portion of the zirconium tungstate phosphate particles, and the particulate portion is easily generated, and the fine particles are easily mixed with the glass powder. When it is dissolved in the heat treatment step, there is a problem that the fluidity of the sealing material is lowered. On the other hand, since the spherical zirconium phosphotungstate used as the negative thermal expansion material of the present invention is a spherical particle, when it is mixed with a hard material, it also has an advantage of suppressing generation of fine particles.

In the present invention, the spherical zirconium phosphotungstate is used as the negative thermal expansion material in the state of monodisperse primary particles, and refers to the primary particles of the zirconium tungstate phosphate particles themselves. The particle shape is spherical. In addition, when the zirconium phosphotungstate is used as the negative thermal expansion material in the state in which the fine primary particles form aggregates and become aggregated particles of the secondary particles, the shape of the aggregated particles themselves is spherical.

In the present invention, the spherical zirconium tungstate phosphate does not necessarily need to be a spherical shape. The sphericity of the spherical zirconium phosphotungstate is preferably in the range of 0.90 or more and 1 or less, and particularly preferably in the range of 0.93 or more and 1 or less, and the dispersion of the positive thermal expansion material and the filling property are excellent. Preferably.

In the present invention, the sphericity is obtained by performing image analysis processing on 50 particles arbitrarily extracted when the sample is observed by an electron microscope at a magnification of 400, and is calculated based on the obtained parameters. That is, the sphericity is represented by the average value of 50 particles obtained by the following calculation formula (1). Sphericality = equal area circle equivalent diameter / circumscribed circle diameter ······(1) Equal area circle equivalent diameter: circumference diameter of the circle corresponding to the circumference of the particle Circumscribed circle diameter: the longest diameter of the particle

Examples of the image analysis device used in the image analysis process include Luzex (manufactured by Nireco Co., Ltd.), PITA-04 (manufactured by Shinsei Co., Ltd.), and the like. The closer the value of the sphericity is to 1, the closer to the spherical shape.

One of the characteristics of the spherical zirconium phosphotungstate used as the negative thermal expansion material of the present invention is that the BET specific surface area is 2.0 m ² /g or less. In the negative thermal expansion material of the present invention, by setting the BET specific surface area to the above range, the interaction between the resin and the negative thermal expansion material can be further reduced, and as a result, the dispersibility to the resin is excellent. On the other hand, when the BET specific surface area of the spherical zirconium tungstate is more than 2.0 m ² /g, for example, when kneaded with a resin, the interaction with the resin is increased, and the viscosity at the time of molding of the resin is improved, and The dispersibility and filling characteristics of the resin are deteriorated, which is not preferable. In the present invention, to further improve the viewpoint of dispersibility and filling properties in terms of positive thermal expansion material, preferably a BET specific surface area of 0.01 m ² / g or more, 2.0 m ² / g or less, particularly preferably 0.01 m ² / g The above is 1.5 m ² /g or less, more preferably 0.01 m ² /g or more and 1.2 m ² /g or less. In order to achieve the BET specific surface area in the above range, for example, in the preferred production method of zirconium phosphate zirconate described later, the calcination temperature and the calcination time may be adjusted.

From the viewpoint of improving the dispersibility and the filling property of the resin, the spherical zirconium phosphotungstate used as the negative thermal expansion material in the present invention preferably contains at least Mg and/or V as a subcomponent element. (hereinafter sometimes referred to simply as "sub-component"). In the present invention, "containing at least Mg and/or V as a sub-element component" means that Mg and/or V must be contained as an accessory component element, and other sub-component elements other than the component may be contained.

Examples of the other elemental component other than Mg and/or V include Zn, Cu, Fe, Cr, Mn, Ni, Li, Al, B, Na, K, F, Cl, Br, I, Ca, Sr, Ba. , Ti, Hf, Nb, Ta, Y, Yb, Si, S, Mo, Co, Bi, Te, Pb, Ag, Cd, In, Sn, Sb, Ga, Ge, La, Ce, Nd, Sm, Eu , Tb, Dy and Ho, etc. These components may be one type or two or more types.

In the present invention, the sphericity is excellent, and the dispersibility and the filling property of the positive thermal expansion material are also improved. The subcomponent element is preferably only Mg and/or V, and particularly preferably Mg and V are used in combination.

The content of the auxiliary component element is preferably 0.1% by mass or more and 3% by mass or less, and particularly preferably 0.2% by mass or more and 2%, from the viewpoint of having excellent negative thermal expansion property and further excellent dispersibility and filling characteristics. %the following. When Mg and V are used in combination, the molar ratio (V/Mg) of V to Mg is preferably 0.1 or more and 2.0 or less, and particularly preferably 0.2, from the viewpoint of improving the multiplication effect of Mg and V. Above, 1.5 or less.

From the viewpoint of the filling property of the positive thermal expansion material, the spherical zirconium phosphate zirconate used as the negative thermal expansion material of the present invention preferably has an average particle diameter of 1 μm or more and 50 μm or less, and particularly preferably 2 μm. Above 30 μm. The average particle diameter is an average value measured by measuring 50 or more particles arbitrarily extracted by scanning electron microscope observation.

When the spherical zirconium phosphotungstate is used as a negative thermal expansion material in the state of monodisperse primary particles, the average particle diameter of the spherical zirconium phosphotungstate is a primary particle of zirconium tungstate phosphate particles. The average particle size of itself. On the other hand, when the zirconium phosphotungstate is used as the negative thermal expansion material in the state in which the fine primary particles form aggregates and become aggregated particles of the secondary particles, the average particle diameter of the aggregated particles themselves. Hereinafter, the case where only the average particle diameter is referred to is based on this definition.

From the viewpoint of the filling property of the positive thermal expansion material, the tap density of the spherical zirconium phosphotungstate used as the negative thermal expansion material of the present invention is preferably 1.3 ml/g or more, and particularly preferably 1.5 ml/g or more and 2.5 ml/g or less.

In the present invention, the knocking degree is a filling property in a state in which the negative thermal expansion material is naturally mixed without being particularly pressurized, and a sample of 50 g or more and 70 g or less is added to the measuring cylinder, and the measuring cylinder is set to automatic. In the TD measuring device, the number of times of the knocking was 500 times, the tightening height was 3.2 mm, and the tempo was tightened 200 times/minute (according to ASTM: B527-93, 85).

From the viewpoint of further improving the filling property of the positive thermal expansion material, the spherical zirconium phosphotungstate used as the negative thermal expansion material of the present invention preferably has a bulk density of 0.8 ml/g or more, and more preferably 1.0 ml/ g ~ 1.6 ml / g.

In the present invention, the bulk density is the mass per unit volume when the powder is filled in a certain container by natural dropping, and can be measured in accordance with JIS K 5101-12-1:2004. Specifically, the bulk density can be measured, for example, using a bulk specific gravity measuring instrument (manufactured by Seiko Scientific Instruments Co., Ltd.).

The negative thermal expansion material of the present invention may be a mixture of spherical coarse particles of zirconium tungstate and fine particles smaller than the coarse particles in order to further improve the filling property. The average particle diameter of the spherical coarse particles of zirconium tungstate is preferably 5 μm or more, and more preferably 5 μm or more and 30 μm or less. On the other hand, the average particle diameter of the spherical fine particles of zirconium tungstate is preferably less than 5 μm, particularly preferably 1 μm or more and 4 μm or less. The average particle diameter is an average value measured by measuring 50 or more particles arbitrarily extracted by scanning electron microscope observation.

The blending ratio of the spherical zirconium phosphotungstate coarse particles and the spherical zirconium phosphate tungstate fine particles may be adjusted so that the knocking degree and the bulk density are within the above range.

The angle of repose of the negative thermal expansion material of the present invention is preferably 50° or less, more preferably 30° or more and 50° or less, and particularly preferably 38° or more, from the viewpoint of the filling property and dispersibility of the positive thermal expansion material. Below 48°.

In the present invention, the angle of repose is an angle formed by a slope of a mountain and a horizontal plane when the powder is naturally dropped and accumulated without spontaneously collapsing but maintaining a stable deposit. Specifically, it can be measured using a measuring device such as a powder tester (manufactured by Hosokawa Micron, PT-N type).

The spherical zirconium phosphotungstate used as the negative thermal expansion material in the present invention is preferably agglomerated particles in which primary particles are aggregated to form secondary particles. Since the aggregated particles have voids between the primary particles, the specific gravity of the particles themselves is smaller than when the spherical zirconium phosphate zirconate is used in a state of monodisperse primary particles, so that the resin can be reduced. Poor specific gravity. For the reason described above, it is possible to suppress sedimentation of the negative thermal expansion material in the resin. In the present invention, the "primary particle" is determined based on the geometric form of the appearance, and is confirmed as the smallest unit of the particle.

In particular, the aggregated particles used as the negative thermal expansion material have a content of preferably 1.2 m ² /g or less, particularly preferably 0.01 m ² /g or more and 1.2 m ² /g or less, particularly preferably 0.01 m ² /g or more. In the case of a spherical shape having a BET specific surface area of 1 m ² /g or less, in the state in which voids exist in the aggregated particles, the voids between the primary particles on the surface of the aggregated particles are suppressed to a low value, so that the resin and the resin cannot be further reduced. The interaction of the negative thermal expansion material results in further improved dispersibility to the resin.

In the case where the spherical zirconium tungstate phosphate is agglomerated particles, the average particle diameter of the primary particles obtained by observation by a scanning electron microscope is preferably 3 μm or less from the viewpoint of maintaining the particles in a spherical shape. It is preferably 0.1 μm or more and 2 μm or less. The average particle diameter of the primary particles is an average value measured by measuring 50 or more particles arbitrarily extracted by scanning electron microscope observation.

Next, a preferred method of producing the negative thermal expansion material of the present invention will be described. The method for producing a negative thermal expansion material of the present invention preferably comprises the following steps. Step A: heat-treating a slurry containing a zirconium compound selected from zirconium hydroxide and zirconium carbonate, phosphoric acid, and a tungsten compound. Step B: The slurry after the step A is subjected to wet pulverization treatment using a media mill. Step C: The slurry after the step B is subjected to spray drying treatment to obtain a spherical reaction precursor. Step D: calcining the spherical reaction precursor. Further, in the production method, at least a compound containing an accessory component element selected from the group consisting of a magnesium compound and/or a vanadium compound may be added before the steps A to B. Hereinafter, each step will be described.

[Step A] In this step, a slurry containing a zirconium compound selected from zirconium hydroxide and zirconium carbonate, phosphoric acid, and a tungsten compound is subjected to heat treatment. Further, as will be described later, the compound containing the accessory component element is added before the steps A to B.

When a phosphoric acid and a zirconium compound are added to a slurry obtained by uniformly dispersing a tungsten compound in advance, the viscosity of the slurry is improved by the tungsten compound, and it is difficult to uniformly mix the raw materials. On the other hand, the present inventors have found that by heat-treating a slurry containing a tungsten compound, a phosphoric acid, and a zirconium compound, the viscosity of the slurry is lowered, and a slurry which can be subjected to wet pulverization treatment by a media mill is obtained.

The zirconium compound used in the step A is at least one of zirconium hydroxide and zirconium carbonate. The zirconium compound can be used without any particular limitation if it is industrially available. Further, the zirconium compound may be an anhydrous salt or an aqueous salt. The zirconium carbonate used as the zirconium compound may be an alkaline salt or a double salt of ammonia or sodium or potassium. The zirconium compound can be directly added to the slurry of the first step as a powder. Alternatively, the zirconium compound may be added as a suspension dispersed in an aqueous solvent or a solution dissolved in an aqueous solvent.

The tungsten compound used in the step A is preferably a compound which is insoluble or poorly soluble with respect to water. Examples of the tungsten compound as described above include tungsten trioxide, ammonium tungstate, and tungsten chloride. Among these compounds, those having high purity can be easily obtained industrially, and from the viewpoint of easy handling, tungsten trioxide is preferred.

The phosphoric acid used in the step A is not particularly limited as long as it is industrially acceptable. Phosphoric acid is useful as an aqueous solution

The zirconium compound is added to the slurry in view of the fact that the negative thermal expansion of the negative thermal expansion material becomes large, and the molar ratio of the Zr element in the zirconium compound in the slurry to the W element in the tungsten compound (Zr/) W) is preferably 1.7 or more and 2.3 or less, and particularly preferably 1.9 or more and 2.1 or less.

The addition amount of phosphoric acid in the slurry is the molar ratio (P/W) of the P element in the phosphoric acid to the W element in the tungsten compound from the viewpoint of the negative thermal expansion of the negative thermal expansion material becoming large. The amount is preferably 1.7 or more and 2.3 or less, and particularly preferably 1.9 or more and 2.1 or less.

The solvent for dispersing the tungsten compound, the phosphoric acid, and the zirconium compound used in the step A is not limited to water, and may be a mixed solvent of water and a hydrophilic solvent. The concentration of the slurry containing the solvent is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more, from the viewpoint of the slurry having the operability and the easy-to-handle viscosity. 30% by mass or less.

In the step A, the order of addition of each raw material is not particularly limited, and the order of addition can be appropriately determined in consideration of a reaction apparatus or the like. In particular, from the viewpoint of easier handling, it is preferred to add phosphoric acid and a zirconium compound to the slurry after preparing a slurry containing a tungsten compound.

The slurry heat treatment temperature in the step A is preferably 40° C. or higher and 110° C. or lower, and particularly preferably 60° C. or higher and 90° C., in terms of the slurry having the operability and the easy-to-handle viscosity. the following.

The time of the heat treatment in the first step is not critical in the present production method, and it is only necessary to carry out the reaction for a sufficient period of time until the slurry viscosity is lowered to a moderate level. In many cases, a satisfactory low-viscosity slurry can be produced by heat treatment of preferably 0.5 hours or more, particularly preferably 1 hour or more and 4 hours or less.

In the production method, at least a compound containing a subcomponent element selected from a magnesium compound and/or a vanadium compound (hereinafter sometimes referred to simply as "" may be referred to as "a" or "B" step before the completion of the step B. A compound containing a subcomponent element ") is added to the slurry. Specifically, in the case where the A step is performed, the middle of the A step, the A step is completed, the B step is performed, and the B step is performed, at least one of the sub-component elements is added. Compound.

Examples of the magnesium compound include oxides, hydroxides, carbonates, organic acid salts, nitrates, phosphates, sulfates, chlorides, bromides, iodides, and the like of magnesium. Among these compounds, when magnesium oxides and hydroxides are used, it is easy to control the purity of the obtained negative thermal expansion material, and it is preferable to obtain a high-purity product.

Examples of the vanadium compound include an oxide, a hydroxide, a carbonate, an organic acid salt, an ammonium salt, a nitrate, a phosphate, a sulfate, a chloride, a bromide, an iodide, and the like of vanadium. Among these compounds, when an oxide and a hydroxide containing vanadium are used, it is easy to control the purity of the obtained negative thermal expansion material, and it is preferable to obtain a high-purity product.

In the production method, a compound containing a sub-component element other than Mg and/or V may be used in combination. In this case, as in the case of adding Mg and/or V, the first step to the second step are as described above. It can be added to the slurry before the step B.

Examples of the compound containing a sub-component element other than Mg and/or V include, for example, Zn, Cu, Fe, Cr, Mn, Ni, Li, Al, B, Na, K, F, Cl, Br, I. , Ca, Sr, Ba, Ti, Hf, Nb, Ta, Y, Yb, Si, S, Mo, Co, Bi, Te, Pb, Ag, Cd, In, Sn, Sb, Te, Ga, Ge, La a compound of at least one of the subcomponent elements of Ce, Nd, Sm, Eu, Tb, Dy, and Ho. These compounds may be used alone or in combination of two or more.

Examples of the compound containing a subcomponent element other than Mg and/or V include an oxide, a hydroxide, a carbonate, an organic acid salt, an ammonium salt, a nitrate, a phosphate, and a sulfate containing the auxiliary component element. , chloride, bromide, iodide, etc. Among these compounds, when an oxide and a hydroxide containing a subcomponent element are used, it is easy to control the purity of the obtained negative thermal expansion material, and it is preferable to obtain a high purity product easily.

Further, for the purpose of dissolving or precipitating the added compound containing the subcomponent element in the slurry, the pH of the slurry may be adjusted with a base or an acid as needed.

The addition amount of the magnesium compound, the vanadium compound, and the compound containing the subcomponent element to be used in the slurry is preferably such that the subcomponent element in the obtained spherical reaction precursor is preferably 0.05% by mass or more and 5.0. The mass% or less is particularly preferably 0.1% by mass or more and 3.0% by mass or less.

In order to obtain high-purity spherical zirconium tungstate phosphate, it is preferred to use a high-purity product for each of the zirconium compound, the phosphoric acid, the tungsten compound, and the compound containing the sub-component element used in the present step.

[Step B] In this step, the slurry after the step A is subjected to wet pulverization treatment by a media mill to obtain a slurry in which each raw material is finely and uniformly dispersed. The media mill can use a bead mill, a ball mill, a paint shaker, a grinder, a sand mill, and the like. It is especially good to use a bead mill. In this case, the operating conditions or the type and size of the beads may be appropriately selected depending on the size of the apparatus or the amount of processing.

From the viewpoint of more efficient treatment using a media mill, a dispersant may also be added to the slurry. The dispersing agent to be used may be selected as appropriate depending on the type of the dispersion medium. In the case where the dispersion medium is, for example, water, various surfactants, polycarboxylate ammonium salts, or the like can be used as the dispersant. The concentration of the dispersing agent in the slurry is 0.01% by mass or more and 10% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.

From the viewpoint of obtaining a spherical reaction precursor having more excellent reactivity, the average particle diameter of the solid component obtained by the wet pulverization treatment using a dielectric mill to the laser diffraction/scattering method is improved. It is preferably 2 μm or less, particularly preferably 1 μm or less, and particularly preferably 0.1 μm or more and 0.5 μm or less.

By the above operation, it is possible to prepare a slurry having a low viscosity in which the raw material components of the subcomponent elements and W, P, and Zr are uniformly dispersed.

[Step C] The slurry after completion of the step B is supplied to the second step of the next step without performing solid-liquid separation, and is spray-dried in the step C to obtain a spherical shape. Reaction precursor. In the spray drying method, the slurry is atomized by a predetermined method, and the fine droplets thus produced are dried to obtain a spherical reaction precursor. Examples of the atomization of the slurry include a method of using a rotating disk and a method of using a pressure nozzle. Any method can be used in this step.

In the spray drying method, the size of the atomized droplets is not particularly limited, but is preferably 1 μm or more and 40 μm or less, and particularly preferably 5 μm or more and 30 μm or less. The amount of slurry supplied to the spray drying device is desirably determined in consideration of this viewpoint.

The hot air temperature in the spray drying device is preferably adjusted to 100° C. or higher and 270° C. or lower, and particularly preferably adjusted to 150° C. or higher and 230, from the viewpoint of preventing moisture absorption of the powder and facilitating recovery of the powder. Below °C.

The spherical reaction precursor obtained by spray drying is a granulated particle containing raw material components W, P, and Zr which form zirconium tungstate phosphate.

The spherical reaction precursor obtained by this step preferably has an absorption peak of infrared rays of at least 950 cm ^-1 or more and 1150 cm ^-1 or less. It is particularly preferable that the maximum value of the infrared absorption peak is 1030 (±20) cm ^-1 in the wave number range. The reason is as follows. As shown in Reference Example 1 described later, when phosphoric acid, tungsten trioxide, and zirconium hydroxide are used to obtain a reaction precursor containing no subcomponent element, when X-ray diffraction analysis is performed on the reaction precursor, only confirmation is performed. To the diffraction peak of tungsten trioxide (see Fig. 1), no diffraction peak of zirconium hydroxide was observed. Further, when the reaction precursor is subjected to FT-IR analysis, zirconium hydroxide and phosphoric acid exhibit different patterns of infrared absorption peaks (see Fig. 2), and it is understood that zirconium hydroxide and phosphoric acid are easily reacted in the slurry. . Therefore, it is considered that the reaction precursor obtained in this step is a pattern which exhibits an infrared absorption peak different from the raw material by the reaction of the zirconium compound with phosphoric acid in the step A. Further, the inventors speculated that the amorphous compound containing phosphorus and zirconium obtained by the reaction of phosphoric acid with zirconium hydroxide is amorphous zirconium phosphate.

[Dth Step] The D step is a step of calcining the spherical reaction precursor obtained in the step C to obtain a spherical squara zirconium tungstate. In the step D, the calcination temperature at which the spherical reaction precursor is calcined is preferably 900 ° C or more and 1300 ° C or less. The reason for this is that the unreacted oxide or the like is hard to remain by setting the calcination temperature to 900 ° C or higher, and there is a tendency that it is easy to obtain zirconium phosphate zirconate which is single phase in X-ray diffraction; When the calcination temperature is set to 1300 ° C or lower, it is difficult to cause a block in which the particles are consolidated, and the powder tends to be easily obtained. In the present production method, since zirconium phosphate zirconate which is single-phase in X-ray diffraction can be obtained at a low temperature, in order to effectively utilize this advantage, it is particularly preferable to set the firing temperature to 900 ° C or more and 1100 ° C or less.

The calcination time is not critical in the present production method, and it is only necessary to carry out a reaction for a sufficient period of time until it is formed into a single-phase zirconium phosphate tungstate during X-ray diffraction. In many cases, zirconium phosphate zirconate having satisfactory physical properties can be produced by calcination of preferably 1 hour or longer, particularly preferably 2 hours or longer and 20 hours or shorter. The calcination environment is not particularly limited, and may be any of an inert gas atmosphere, a vacuum atmosphere, an oxidizing gas atmosphere, and an atmosphere.

Calcination can be carried out as many times as necessary. Alternatively, for the purpose of making the powder characteristics uniform, the primary calciner may be pulverized and then re-calcined.

After calcination, it is appropriately cooled, and if necessary, pulverized, crushed, classified, or the like, and the intended zirconium tungstate phosphate can be obtained. The zirconium tungstate phosphate has a negative thermal expansion coefficient and is single phase in X-ray diffraction and is spherical.

The negative thermal expansion material of the present invention may use a powder or a paste. When used as a paste, it can be used in the state of the paste of the liquid resin with low viscosity. Alternatively, the solvent may be contained, and if necessary, a paste containing a binder, a fluxing material, a dispersing agent, or the like may be used.

The blending amount of the negative thermal expansion material in the paste is not particularly limited, but in many cases, it is preferably 5% by volume or more and 65% by volume or less.

The paste containing the negative thermal expansion material of the present invention, and further comprising a binder and a fluxing material, for example, can be suitably used as a sealing material.

The solvent used in the paste is generally used in the art. For example, N,N'-dimethylformamide, ethylene glycol, dimethyl hydrazine, dimethyl carbonate, propyl carbonate, butyrolactone, caprolactone, N-methyl-2 - pyrrolidone, butyl carbitol acetate, propylene glycol diacetate, alpha-terpineol, alpha-terpineol, gamma-butyl lactone, tetrahydrogen phosphate, acetic acid Ester, isoamyl acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, benzyl alcohol, toluene, 3-methoxy-3-methylbutanol, triethylene glycol monomethyl ether , dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether and the like.

The binder used in the paste is generally used in the art. For example, nitrocellulose, ethylcellulose, polyvinyl carbonate, polypropylene carbonate, acrylate, methacrylate, polyethyleneglycol derivative, polymethylstyrene, etc. are mentioned.

The fluxing material used in the paste may, for example, be a low melting point glass, and is generally used in the art. For example, PbO-B ₂ O ₃ system, PbO-SiO ₂ -B ₂ O ₃ system, Bi ₂ O ₃ -B ₂ O ₃ system, Bi ₂ O ₃ -SiO ₂ -B ₂ O ₃ system, SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ system, SiO ₂ -B ₂ O ₃ -BaO system, SiO ₂ -B ₂ O ₃ -CaO system, ZnO-B ₂ O ₃ -Al ₂ O ₃ system, ZnO-SiO ₂ -B ₂ O ₃ system, P ₂ O ₅ system, SnO-P ₂ O ₅ system, V ₂ O ₅ -P ₂ O ₅ system, V ₂ O ₅ -Mo ₂ O ₃ system, and V ₂ O ₅ - P ₂ O ₅ -TeO ₂ and the like.

The negative thermal expansion material of the present invention is contained in a positive thermal expansion material to form a composite material, and a material having a negative thermal expansion, zero thermal expansion, or low thermal expansion can be obtained according to a blending ratio of the negative thermal expansion material.

The negative thermal expansion material of the present invention may be used in combination with other negative thermal expansion materials or fillers for adjusting the thermal expansion coefficient within a range that does not impair the effects of the present invention. Other negative thermal expansion materials or fillers for adjusting the thermal expansion coefficient include, for example, zirconium tungstate (ZrW ₂ O ₈ ), Zn _x Cd _1-x (CN) ₂ , trimanganese dinitride, niobium nickel, iron oxide. , zirconium phosphate, cordierite, zircon, zirconium oxide, tin oxide, antimony oxide, quartz, β-quartz, β-spudumene, β-eucryptite, mullite (mullite), quartz glass, NbZr(PO ₄ ) ₃ , molten cerium oxide or the like, but is not particularly limited to these fillers.

Examples of the positive thermal expansion material containing the negative thermal expansion material of the present invention include various organic compounds or inorganic compounds. Examples of the organic compound include rubber, polyolefin, polycycloolefin, polystyrene, acrylonitrile butadiene styrene (ABS), polyacrylate, polyphenylene sulfide, phenol resin, and polyfluorene. An amine resin, a polyimide resin, an epoxy resin, an anthrone resin, a polycarbonate resin, a polyethylene resin, a polypropylene resin, a polyethylene terephthalate resin (PET) resin, and Polyvinyl chloride resin, etc. Examples of the inorganic compound include metals, alloys, cerium oxide, graphite, sapphire, various glasses, concrete materials, various ceramic materials, and the like. Among these compounds, the positive thermal expansion material is preferably at least one selected from the group consisting of metals, alloys, glass, ceramics, rubbers, and resins. In the composite material of the present invention, the addition amount of the negative thermal expansion material of the present invention can be generally added in the art. [Examples]

Hereinafter, the present invention will be further described in detail by way of examples, but the scope of the invention is not limited thereto.

<Evaluation device> 1. X-ray diffraction analysis: X-ray diffraction analysis of zirconium tungstate phosphate and reaction precursor was carried out using Rigaku's Ultima IV. Cu-Kα was used as a line source. The measurement conditions were a tube voltage of 40 kV, a tube current of 40 mA, and a scanning speed of 0.1°/sec. 2. Infrared Absorption Spectroscopy (FT-IR) Analysis: The infrared absorption spectrum analysis of the reaction precursor was performed using a NICOLET 6700 manufactured by Thermo Fisher Scientific, with a decomposition capacity of 4 cm ^{- 1} , cumulative number: 256 times, measured wave number area: 400 cm ^-1 ~ 4000 cm ^-1 conditions to determine. The ATR correction and the smoothing processing of the spectrum were performed by an attenuated total reflection (ATR) method. 3. Average particle size: The average particle size of the solid components in each raw material and slurry is laser diffraction/scattering method using Microtrac MT3300EXII particle size analyzer (MicrotracBEL) Manufacture) to determine.

<Negative thermal expansion material> [Reference Example 1] 15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter: 1.2 μm) was placed in a beaker, and 84 parts by mass of pure water was further added thereto, and 1 part by mass was charged. A polycarboxylate ammonium salt as a dispersing agent. The mixture was stirred at room temperature (25 ° C) for three minutes using a Three-One Motor mixer to prepare a 15% by mass slurry containing tungsten trioxide. The solid content of the solid content in the slurry was 1.2 μm. Then, in the slurry, zirconium hydroxide and an 85 mass% phosphoric acid aqueous solution were added at room temperature (25 ° C) so that the molar ratio of Zr:W:P in the slurry was 2.00:1.00:2.00. The reaction was carried out for 2 hours while stirring. After completion of the reaction, the total amount of the slurry was dried at 200 ° C for 24 hours in the air to obtain a reaction precursor. X-ray diffraction of the obtained reaction precursor was carried out, and as a result, only a diffraction peak of tungsten trioxide was observed (refer to Fig. 1 (a)). Further, as a result of analysis by FT-IR, an infrared absorption peak was observed at 950 cm ^-1 to 1150 cm ^-1 , and the maximum value of the infrared absorption peak at this time appeared at 1027 cm ^-1 (refer to Fig. 2). Then, the obtained reaction precursor was calcined in the atmosphere at 1,050 ° C for 2 hours to obtain a white calcined product. As a result of performing X-ray diffraction analysis on the obtained calcined product, the calcined product was a single phase of Zr ₂ (WO ₄ )(PO ₄ ) ₂ . This was pulverized by a jet mill to be used as a sample of a negative thermal expansion material.

[Example 1] 15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter: 1.2 μm) was placed in a beaker, and further 84 parts by mass of pure water was added. The mixture was stirred at room temperature (25 ° C) for 120 minutes to prepare a 15% by mass slurry containing tungsten trioxide. The solid content of the solid content in the slurry was 1.2 μm. Then, in the slurry, zirconium hydroxide and 85 mass are added at room temperature (25 ° C) so that the molar ratio of Zr:W:P:Mg in the slurry becomes 2.00:1.00:2.00:0.1. After the % phosphoric acid aqueous solution and magnesium hydroxide, the temperature was raised to 80 ° C, and the reaction was carried out for 4 hours while stirring. After completion of the reaction, 1 part by mass of a polycarboxylate ammonium salt as a dispersing agent was charged, and the slurry was supplied to a medium agitating bead mill in which zirconia beads having a diameter of 0.5 mm were placed while stirring, and mixed for 15 minutes. To carry out wet pulverization. The average particle diameter of the solid content in the slurry after the wet pulverization was 0.3 μm. Then, in a spray dryer set at 220 ° C, the slurry was supplied at a supply rate of 2.4 L/h to obtain a reaction precursor. X-ray diffraction of the obtained reaction precursor was carried out, and as a result, only a diffraction peak of tungsten trioxide was observed (refer to Fig. 3). Further, as a result of analysis by FT-IR, an infrared absorption peak was observed at 950 cm ^-1 to 1150 cm ^-1 , and the maximum value of the infrared absorption peak at this time appeared at 1042 cm ^-1 (see Fig. 4). Then, the obtained reaction precursor was calcined in the atmosphere at 1,050 ° C for 2 hours to obtain a white calcined product. As a result of performing X-ray diffraction analysis on the obtained calcined product, the calcined product was a single phase of Zr ₂ (WO ₄ )(PO ₄ ) ₂ . This was taken as a negative thermal expansion material sample.

[Example 2] 15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter: 1.2 μm) was placed in a beaker, and further 84 parts by mass of pure water was added, and 1 part by mass of a polydispersant was charged. Ammonium carboxylate. The mixture was stirred at room temperature (25 ° C) for 120 minutes to prepare a 15% by mass slurry containing tungsten trioxide. The solid content of the solid content in the slurry was 1.2 μm. Then, in the slurry, hydrogen peroxide was added at room temperature (25 ° C) so that the molar ratio of Zr:W:P:Mg:V in the slurry was 2.00:1.00:2.00:0.1:0.05. Zirconium, an 85 mass% phosphoric acid aqueous solution, magnesium hydroxide, and vanadium pentoxide were heated to 80 ° C, and reacted for 4 hours while stirring. After completion of the reaction, the slurry was supplied to a medium agitating bead mill into which zirconia beads having a diameter of 0.5 mm were placed, and mixed for 15 minutes to carry out wet pulverization. The average particle diameter of the solid content in the slurry after the wet pulverization was 0.3 μm. Then, in a spray dryer set at 220 ° C, the slurry was supplied at a supply rate of 2.4 L/h to obtain a reaction precursor. X-ray diffraction of the obtained reaction precursor was carried out, and as a result, only a diffraction peak of tungsten trioxide was observed. Further, as a result of analysis by FT-IR, an infrared absorption peak was observed at 950 cm ^-1 to 1150 cm ^-1 , and the maximum value of the infrared absorption peak at this time appeared at 1030 cm ^-1 . Then, the obtained reaction precursor was calcined in the atmosphere at 1,050 ° C for 2 hours to obtain a white calcined product. As a result of performing X-ray diffraction analysis on the obtained calcined product, the calcined product was a single phase of Zr ₂ (WO ₄ )(PO ₄ ) ₂ . This was taken as a negative thermal expansion material sample.

[Example 3] 15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter: 1.2 μm) was placed in a beaker, and further 84 parts by mass of pure water was added. The mixture was stirred at room temperature (25 ° C) for 120 minutes to prepare a 15% by mass slurry containing tungsten trioxide. The solid content of the solid content in the slurry was 1.2 μm. Then, in the slurry, zirconium hydroxide and an 85 mass% phosphoric acid aqueous solution were added at room temperature (25 ° C) so that the molar ratio of Zr:W:P in the slurry was 2.00:1.00:2.00. Thereafter, the temperature was raised to 80 ° C, and the reaction was carried out for 4 hours while stirring. After completion of the reaction, 1 part by mass of a polycarboxylate ammonium salt as a dispersing agent was charged, and the slurry was supplied to a medium agitating bead mill in which zirconia beads having a diameter of 0.5 mm were placed while stirring, and mixed for 15 minutes. To carry out wet pulverization. The average particle diameter of the solid content in the slurry after the wet pulverization was 0.3 μm. Then, in a spray dryer set at 220 ° C, the slurry was supplied at a supply rate of 2.4 L/h to obtain a reaction precursor. X-ray diffraction of the obtained reaction precursor was carried out, and as a result, only a diffraction peak of tungsten trioxide was observed. Further, as a result of analysis by FT-IR, an infrared absorption peak was observed at 950 cm ^-1 to 1150 cm ^-1 , and the maximum value of the infrared absorption peak at this time appeared at 1042 cm ^-1 . Then, the obtained reaction precursor was calcined in the atmosphere at 1220 ° C for 8 hours to obtain a white calcined product. As a result of performing X-ray diffraction analysis on the obtained calcined product, the calcined product was a single phase of Zr ₂ (WO ₄ )(PO ₄ ) ₂ . This was taken as a negative thermal expansion material sample.

[Reference Example 2] 15 parts by mass of commercially available tungsten trioxide (WO ₃ ; average particle diameter: 25 μm) was weighed and placed in a tank. 84 parts by mass of pure water and 1 part by mass of a polycarboxylic acid ammonium salt as a dispersing agent were charged into the tank. Then, the slurry was supplied to a medium agitating bead mill in which zirconia beads having a diameter of 0.5 mm were placed while being stirred, and mixed for 15 minutes to carry out wet pulverization. The average particle diameter of the solid content in the slurry after the wet pulverization was 0.3 μm. Then, in the slurry, zirconium hydroxide and an 85 mass% phosphoric acid aqueous solution were added at room temperature (25 ° C) so that the molar ratio of Zr:W:P in the slurry was 2.00:1.00:2.00. The reaction was carried out for 2 hours while stirring. After completion of the reaction, the slurry was supplied at a supply rate of 2.4 L/h in a spray dryer set at 220 ° C to obtain a reaction precursor. X-ray diffraction of the obtained reaction precursor was carried out, and as a result, only a diffraction peak of tungsten trioxide was observed. Further, as a result of analysis by FT-IR, an infrared absorption peak was observed at 950 cm ^-1 to 1150 cm ^-1 , and the maximum value of the infrared absorption peak at this time appeared at 1030 cm ^-1 . Then, the obtained reaction precursor was calcined in the atmosphere at 1,050 ° C for 2 hours to obtain a white calcined product. As a result of performing X-ray diffraction analysis on the obtained calcined product, the calcined product was a single phase of Zr ₂ (WO ₄ )(PO ₄ ) ₂ . This was taken as a negative thermal expansion material sample.

<Evaluation of physical properties> The content of the subcomponent element, the sphericity, the average primary particle diameter, the average secondary particle diameter (agglomerated particle diameter), the BET specific surface area, and the knocking tightness were measured for the zirconium phosphate zirconate obtained in the examples and the reference examples. Degree, bulk density, angle of repose and coefficient of thermal expansion. The results are shown in Table 1. Further, an SEM photograph of zirconium phosphate zirconate obtained in Example 1 is shown in Figs. 6(a) and (b).

(Measurement of Average Primary Particle Diameter) The average primary particle diameter of zirconium tungstate phosphate is determined from the average value of 50 or more particles arbitrarily extracted at a magnification of 5,000 times in scanning electron microscope observation. The particle size is set to the maximum lateral length of each particle.

(Measurement of Average Secondary Particle Diameter) The average secondary particle diameter of zirconium tungstate phosphate is determined from the average value of 50 or more particles which are arbitrarily extracted at a magnification of 400 times in scanning electron microscope observation. The particle size is set to the maximum lateral length of each particle.

(Measurement of sphericity) The sphericity is obtained by using 50 granules arbitrarily extracted at a magnification of 400 times using Luzex (manufactured by Nireco Co., Ltd.), which is obtained by the following calculation formula. . Sphericality = equal area circle equivalent diameter / circumscribed circle diameter Equal area circle equivalent diameter: circumference diameter of the circle corresponding to the circumference of the particle Circumscribed circle diameter: the longest diameter of the particle

(Measurement of bulk density) According to the JIS 5101-12-1 pigment test method, a sample (capacity: 30 mL) in a bulk specific gravity measuring device (capacity: 30 mL) is used to receive a sample through a sieve until it is received from a receiver. In the middle overflow, the excess portion was flattened by a doctor blade, and the mass of the sample stored in the receiver was measured to calculate the bulk density (g/mL).

(Evaluation of the knocking degree) Using a funnel, 10 g of the sample powder of a predetermined mass was placed in a measuring cylinder, and set in a tightening device (manufactured by Quantachrome Instrument, DUAL AUTOTAP) In the above, the measurement conditions were set to 500 times of the number of times of tightening, 3.2 mm of the tightening height, and 200 times of the knocking rhythm, and were obtained according to the following formula (according to ASTM: B527-93, 85). Knock tightness = powder mass / volume after knocking

(Evaluation of the angle of repose) The angle of the mountain of the powder layer formed in a state in which it was naturally dropped by the sample injection method was measured using a powder tester (manufactured by Hosokawa Micron, PT-N type). .

(Contents of the accessory component elements Mg and V) The measurement was carried out by a wavelength dispersion type fluorescent X-ray analyzer (Rigaku Corporation, model ZSX100e).

(Evaluation of coefficient of thermal expansion) The X-ray Diffractometer (XRD) device (Rigaku Corporation, Ultima IV) with a temperature rising function was used to achieve the target at a temperature rising rate of 20 ° C/min. After 10 minutes, the lattice constant of the sample with respect to the a-axis, the b-axis, and the c-axis was measured, and the lattice volume change (cuboid) was linearly converted to obtain a coefficient of thermal expansion (refer to Journal of Materials). Science, J. Mat. Sci.)", 35 (2000) pp. 2451-2454).

[Table 1]

<Preparation of Resin Composite> [Example 4] 5.8 g of the sample of the negative thermal expansion material obtained in Example 1 and 4.2 g of the liquid epoxy resin (Mitsubishi Chemical, jER807, epoxy equivalent of 160 to 175) were weighed. It was mixed with a vacuum mixer (manufactured by Thinky, defoaming Ryotaro ARV-310) at a rotational speed of 2000 rpm to prepare a 30 vol% paste. Regarding the viscosity of the paste, a rheometer (manufactured by Thermo Fisher Scientific, HAAKE MARS II) was used to measure the shear rate 1 [1/s] and the shear rate 10 [ 1/s], viscosity at 25 ° C. In addition, 100 μL of a hardener (Curezol, manufactured by Shikoku Kasei Co., Ltd.) was added to the paste, and a vacuum mixer (manufactured by Thinky, defoaming Rantaro ARV-310) was used at a rotation speed of 1500. The mixture was mixed at rpm, and hardened at 150 ° C for 1 hour to obtain a resin composite. The resin composite was cut into 5 mm square × 10 mm, and a linear expansion coefficient of 30 ° C to 120 ° C was measured at a temperature increase rate of 1 ° C / min using a thermomechanical analysis (TMA).

[Example 5] 5.8 g of the negative thermal expansion material sample obtained in Example 2 and 4.2 g of an epoxy resin (Mitsubishi Chemical, jER807, epoxy equivalent 160 to 175) were metered, using a vacuum mixer (new base ( Manufactured by Thinky), defoaming RITAR ARV-310), mixed at a rotation speed of 2000 rpm to produce 30 vol% paste. Regarding the viscosity of the paste, a rheometer (manufactured by Thermo Fisher Scientific, HAAKE MARS II) was used to measure the shear rate 1 [1/s] and the shear rate 10 [ 1/s], viscosity at 25 ° C. In addition, 100 μL of a hardener (Curezol, manufactured by Shikoku Kasei Co., Ltd.) was added to the paste, and a vacuum mixer (manufactured by Thinky, defoaming Rantaro ARV-310) was used at a rotation speed of 1500. The mixture was mixed at rpm, and hardened at 150 ° C for 1 hour to obtain a resin composite. The resin composite was cut into 5 mm square × 10 mm, and a linear expansion coefficient of 30 ° C to 120 ° C was measured at a temperature increase rate of 1 ° C / min using a thermomechanical analyzer (TMA).

[Example 6] 5.8 g of the sample of the negative thermal expansion material obtained in Example 3 and 4.2 g of the liquid epoxy resin (Mitsubishi Chemical, jER807, epoxy equivalent of 160 to 175) were metered, using a vacuum mixer (new Manufactured by Thinky, defoaming Rantaro ARV-310), mixed at a rotation speed of 2000 rpm to prepare a 30 vol% paste. Regarding the viscosity of the paste, a rheometer (manufactured by Thermo Fisher Scientific, HAAKE MARS II) was used to measure the shear rate 1 [1/s] and the shear rate 10 [ 1/s], viscosity at 25 ° C. In addition, 100 μL of a hardener (Curezol, manufactured by Shikoku Kasei Co., Ltd.) was added to the paste, and a vacuum mixer (manufactured by Thinky, defoaming Rantaro ARV-310) was used at a rotation speed of 1500. The mixture was mixed at rpm, and hardened at 150 ° C for 1 hour to obtain a resin composite. The resin composite was cut into 5 mm square × 10 mm, and a linear expansion coefficient of 30 ° C to 120 ° C was measured at a temperature increase rate of 1 ° C / min using a thermomechanical analyzer (TMA).

[Reference Example 3] 5.8 g of the negative thermal expansion material obtained in Reference Example 1 and 4.2 g of epoxy resin (Mitsubishi Chemical, jER807, epoxy equivalent of 160 to 175) were measured, and a vacuum mixer (Thinky) was used. Manufactured, defoamed Ryotaro ARV-310), and mixed at a rotation speed of 2000 rpm to prepare a 30 vol% paste. Regarding the viscosity of the paste, a rheometer (manufactured by Thermo Fisher Scientific, HAAKE MARS II) was used to measure the shear rate 1 [1/s] and the shear rate 10 [ 1/s], viscosity at 25 ° C. In addition, 100 μL of a hardener (Curezol, manufactured by Shikoku Kasei Co., Ltd.) was added to the paste, and a vacuum mixer (manufactured by Thinky, defoaming Rantaro ARV-310) was used at a rotation speed of 1500. The mixture was mixed at rpm, and hardened at 150 ° C for 1 hour to obtain a resin composite. The resin composite was cut into 5 mm square × 10 mm, and a linear expansion coefficient of 30 ° C to 120 ° C was measured at a temperature increase rate of 1 ° C / min using a thermomechanical analyzer (TMA).

[Reference Example 4] 5.8 g of the negative thermal expansion material obtained in Reference Example 2 and 4.2 g of epoxy resin (Mitsubishi Chemical, jER807, epoxy equivalent of 160 to 175) were measured, and a vacuum mixer (Thinky) was used. Manufactured, defoamed Ryotaro ARV-310), and mixed at a rotation speed of 2000 rpm to prepare a 30 vol% paste. Regarding the viscosity of the paste, a rheometer (manufactured by Thermo Fisher Scientific, HAAKE MARS II) was used to measure the shear rate 1 [1/s] and the shear rate 10 [ 1/s], viscosity at 25 ° C. In addition, 100 μL of a hardener (Curezol, manufactured by Shikoku Kasei Co., Ltd.) was added to the paste, and a vacuum mixer (manufactured by Thinky, defoaming Rantaro ARV-310) was used at a rotation speed of 1500. The mixture was mixed at rpm, and hardened at 150 ° C for 1 hour to obtain a resin composite. The resin composite was cut into 5 mm square × 10 mm, and a linear expansion coefficient of 30 ° C to 120 ° C was measured at a temperature increase rate of 1 ° C / min using a thermomechanical analyzer (TMA).

[Reference Example 5] 3.3 g of spherical molten cerium oxide having an average particle diameter of 10 μm (linear expansion coefficient of 5 × 10 ^-7 /°C) and 4.2 g of epoxy resin (Mitsubishi Chemical, jER807, epoxy) The equivalent weight was 160 to 175), and it was mixed by a vacuum mixer (manufactured by Thinky, defoaming Ryotaro ARV-310) at a rotational speed of 2000 rpm to prepare a 30 vol% paste. Regarding the viscosity of the paste, a rheometer (manufactured by Thermo Fisher Scientific, HAAKE MARS II) was used to measure the shear rate 1 [1/s] and the shear rate 10 [ 1/s], viscosity at 25 ° C. In addition, 100 μL of a hardener (Curezol, manufactured by Shikoku Kasei Co., Ltd.) was added to the paste, and a vacuum mixer (manufactured by Thinky, defoaming Rantaro ARV-310) was used at a rotation speed of 1500. The mixture was mixed at rpm, and hardened at 150 ° C for 1 hour to obtain a resin composite. The resin composite was cut into 5 mm square × 10 mm, and a linear expansion coefficient of 30 ° C to 120 ° C was measured at a temperature increase rate of 1 ° C / min using a thermomechanical analyzer (TMA).

[Table 2]

According to the results of Table 2, the negative thermal expansion materials of Examples 1, 2, and 3 were compared with Reference Example 1 and Reference Example 2, and when the resin was blended in the resin, the viscosity during molding of the resin was also suppressed. It is a low value, and can be formed by the viscosity similar to the molten cerium oxide (Reference Example 5).

no

1 is an X-ray diffraction diagram of a reaction precursor obtained in Reference Example 1. 2(a) is a Fourier transform-infrared (FT-IR) spectrum of the reaction precursor obtained in Reference Example 1, and FIG. 2(b) is an FT-IR spectrum diagram of zirconium hydroxide. 2(c) is an FT-IR spectrum of phosphoric acid, and FIG. 2(d) is an FT-IR spectrum of tungsten trioxide. 3 is an X-ray diffraction diagram of the reaction precursor obtained in Example 1. 4 is a FT-IR spectrum chart of the reaction precursor obtained in Example 1. Fig. 5 is an X-ray diffraction diagram of zirconium phosphate zirconate obtained in Example 1. Fig. 6(a) is a Scanning Electron Microscope (SEM) photograph of the zirconium phosphate zirconate obtained in Example 1 (magnification: 30,000 times), and Fig. 6(b) is the same as Fig. 6(a). SEM photo (but the magnification is 400 times).

Claims (12)

A negative thermal expansion material comprising spherical zirconium tungstate phosphate having a Buerte specific surface area of 2 m ² /g or less. The negative thermal expansion material according to claim 1, wherein the sphericity is 0.90 or more and 1 or less. The negative thermal expansion material according to claim 1 or 2, further comprising at least Mg and/or V as an accessory component element. The negative thermal expansion material according to any one of claims 1 to 3, wherein the content of the accessory component element is 0.1% by mass or more and 3% by mass or less. The negative thermal expansion material according to any one of claims 1 to 4, wherein the subcomponent element is Mg and/or V. The negative thermal expansion material according to any one of the items 1 to 5, wherein the average particle diameter is 1 μm or more and 50 μm or less. The negative thermal expansion material according to any one of claims 1 to 6, wherein the knock tightness is 1.3 g/ml or more. The negative thermal expansion material according to any one of the preceding claims, wherein the spherical zirconium phosphotungstate is aggregated particles in which primary particles are aggregated to form secondary particles. The negative thermal expansion material according to claim 8, wherein the Bouette specific surface area is 1.2 m ² /g or less. A paste comprising the negative thermal expansion material according to any one of claims 1 to 9. A composite material comprising the negative thermal expansion material and the positive thermal expansion material according to any one of claims 1 to 9. The composite material according to claim 11, wherein the positive thermal expansion material is at least one selected from the group consisting of metals, alloys, glass, ceramics, rubber, and resins.