WO2017104235A1

WO2017104235A1 - Gas adsorbing material

Info

Publication number: WO2017104235A1
Application number: PCT/JP2016/079580
Authority: WO
Inventors: 秀哉山本; 晃平坂田
Original assignee: 旭ファイバーグラス株式会社
Priority date: 2015-12-15
Filing date: 2016-10-05
Publication date: 2017-06-22
Also published as: JP2017109150A; JP6806439B2

Abstract

Provided is a gas adsorbing material which exhibits high gas adsorption capacity. The porosity of this gas adsorbing material is controlled to 40-80% by using a binder that is composed of calcium silicate or magnesium silicate together with zeolite and calcium oxide.

Description

Gas adsorbent

The present invention relates to a gas adsorbent. In particular, the present invention relates to a gas adsorbent that adsorbs an intruding gas in a vacuum heat insulating material, a vacuum heat insulating structure, or a vacuum glass sash.

In the vacuum heat insulating material obtained by sealing the core material in the packaging bag under reduced pressure, moisture existing in the packaging bag from the beginning of manufacture, moisture entering the packaging bag from the outside, nitrogen gas, carbon dioxide gas, etc. However, there exists a possibility of reducing the heat insulation performance of a vacuum heat insulating material. In order to avoid problems caused by moisture and intrusion gas, it has been proposed to store an adsorbent together with a core material inside the packaging bag and adsorb the moisture and gas to the adsorbent.

Generally, zeolite ion-exchanged with metals such as copper and silver is known to adsorb nitrogen gas, carbon dioxide gas, and oxygen gas, and is used as a gas adsorbent. The zeolite can adsorb moisture in addition to the gas described above, but when moisture is adsorbed, the function as a gas adsorbent is reduced. In order to prevent moisture adsorption by the zeolite, it has been proposed to use a moisture adsorbent together with the zeolite. Calcium oxide is used as the moisture adsorbing material.

Patent Document 1 discloses a gas adsorbent used for adsorbing air in a closed space to maintain a reduced pressure state in the closed space, wherein the ratio of silica to alumina in the zeolite skeleton is 8 or more and 25 or less. There has been proposed a gas adsorbent characterized by covering the periphery of the ZSM-5 type zeolite with a chemical moisture adsorbent having a greater adsorption activity with respect to water than that of the ZSM-5 type zeolite exchanged with copper. Patent Document 1 discloses calcium oxide as a chemical moisture adsorbent.

JP 2012-217842 A

In the gas adsorbent of Patent Document 1, since zeolite is covered with calcium oxide, moisture adsorption of zeolite can be prevented. However, since the exposed surface area of zeolite becomes small, gas adsorption ability may be insufficient. .

An object of the present invention is to provide a gas adsorbent exhibiting high gas adsorbing ability.

It has been found that the above problem can be solved by adjusting the porosity of the gas adsorbent to 40 to 80% using a binder made of calcium silicate or magnesium silicate together with zeolite and calcium oxide. That is, the present invention relates to the following [1] to [14].

[1] A gas adsorbent containing zeolite, calcium oxide, and a binder,
The zeolite is ion-exchanged with one or more metal ions selected from the group consisting of copper, silver, gold, iron, zinc and nickel ions;
The zeolite has an average pore diameter of 0.3 to 1.3 nm,
The binder is calcium silicate or magnesium silicate;
The gas adsorbent has a porosity of 40 to 80%.
A gas adsorbent characterized by that.

[2] The gas adsorbent according to [1], wherein the binder is calcium silicate.

[3] The gas adsorbent according to [2], wherein the calcium silicate is dobermorite, wollastonite, or Portland cement.

[4] The gas adsorbent according to [1], wherein the binder is magnesium silicate.

[5] The gas adsorbent according to [4], wherein the magnesium silicate is sepiolite, attapulgite, or talc.

[6] The gas adsorbent according to any one of [1] to [5], wherein the content of the binder is 5% by mass to 25% by mass with respect to the total mass of the gas adsorbent.

[7] The gas adsorbent according to any one of [1] to [6], wherein the metal ions are at least one selected from the group consisting of copper, silver, iron and nickel ions.

[8] The above [1] to [7], wherein the ion exchange rate in the zeolite is 40 to 120 mol% with respect to the total number of moles of alkali metal and alkaline earth metal contained in the zeolite before ion exchange. The gas adsorbent according to any one of the above.

[9] The gas adsorbent according to any one of [1] to [8], wherein the zeolite content is 5% by mass to 40% by mass with respect to the total mass of the gas adsorbent.

[10] The gas adsorbent according to any one of [1] to [9], which is a compression molded product.

[11] The gas adsorbent according to any one of [1] to [10], which is used for a vacuum heat insulating material.

[12] From the gas-adsorbing material according to any one of [1] to [11], a core material made of an inorganic fiber mat, and a gas barrier sheet material enclosing the gas-adsorbing material and the core material. A vacuum insulation material, including a packaging bag.

[13] A method for producing a gas adsorbent, comprising:
A step of mixing a zeolite, calcium oxide and a binder without adding water to obtain a mixture, and a step of compression-molding the mixture,
Including
The zeolite is ion-exchanged with one or more metal ions selected from the group consisting of copper, silver, gold, iron, zinc and nickel ions;
The zeolite has an average pore diameter of 0.3 to 1.3 nm,
The binder is calcium silicate or magnesium silicate;
The porosity of the gas adsorbent is 40 to 80%.
A method characterized by that.

[14] The method according to [13], wherein the compression molding step is performed at a molding pressure of 50 to 200 MPa.

According to the present invention, a gas adsorbent having a high gas adsorption capacity is provided.

The present invention is a gas adsorbent comprising zeolite, calcium oxide, and a binder,
The zeolite is ion-exchanged with one or more metal ions selected from the group consisting of copper, silver, gold, iron, zinc and nickel ions;
The zeolite has an average pore diameter of 0.3 to 1.3 nm,
The binder is calcium silicate or magnesium silicate;
The gas adsorbent has a porosity of 40 to 80%.
The present invention relates to a gas adsorbent.

Zeolite The zeolite in the present invention has an average pore diameter of 0.3 to 1.3 nm, preferably 0.5 to 1.3 nm. If the average pore diameter is in the above range, it is 4 to 15 times the molecular diameter of nitrogen, carbon dioxide and oxygen to be adsorbed, and the target gas can be sufficiently adsorbed. The average pore diameter can be measured by a pore distribution measuring device using a nitrogen gas or argon gas adsorption method.

Examples of zeolite having an average pore size of 0.3 to 1.3 nm include the following.

The value of n in the chemical formula of ZSM-5 type zeolite is preferably 20 to 50, more preferably 30 to 45.

Zeolite has a structure in which alumina is bonded and incorporated in the form of a high molecular weight silicon oxide skeleton in the form of aluminate (AlO ₄ ⁻ ), and aluminum atoms are negatively charged. Near the aluminum atoms, there are alkali metals such as sodium and potassium ionized by the bound water of the zeolite, and alkaline earth metals such as calcium and magnesium. It can be moved to. Movable metal ions can be easily ion exchanged with other metal ions. It is publicly known that the gas adsorption capacity changes depending on the nature of the metal ion, and the type of the metal ion is selected according to the purpose of use.

The gas adsorbent of the present invention is targeted for adsorption of nitrogen gas, carbon dioxide gas, oxygen gas and the like. In accordance with the adsorption target, the zeolite of the present invention is ion-exchanged with one or more metal ions selected from the group consisting of copper, silver, gold, iron, zinc and nickel ions. Copper ions or silver ions are preferable metal ions because of their high gas adsorption capacity.

The metal ions are used for ion exchange of zeolite in the form of weak acid-base salts. Examples of the weak acid base salt include inorganic salts such as carbonate, bicarbonate, phosphate, phosphite, hypophosphite, formate, acetate, propionate, oxalate, malonate , Succinate, glutarate, lactate, malate, citrate and the like, and aliphatic organic acid salts having 4 or less carbon atoms. In the case of the aliphatic organic acid salt, if the number of carbon atoms is 4 or less, the solubility in water is high, and the reduction of the metal ion exchange rate can be prevented.

The ion exchange rate in the zeolite used in the present invention is preferably 40 to 120 mol%, preferably 60 to 100 mol, based on the total number of moles of alkali metal and alkaline earth metal contained in the zeolite before ion exchange. % Is more preferable. The ion exchange rate exceeding 100 mol% refers to the case where excess metal ions are present on the zeolite surface, and the excess metal ions react with oxygen or water to form metal oxides or metal on the zeolite surface. Form hydroxide. When the ion exchange rate is 40 mol% or more, the adsorption activity of the intruding gas in the vacuum heat insulating material is sufficient, and the heat insulating property is not deteriorated by long-term use. Further, when the ion exchange rate is 120 mol% or less, excess metal ions are not present on the zeolite surface or a small amount even if they are present, the metal oxide or metal hydroxide formed from the excess metal ions. Thus, the surface of the zeolite is not covered, and the adsorption area of the zeolite is not reduced.

The ion exchange rate is determined by obtaining the amount (mass%) of each constituent element from the image obtained by elemental analysis by energy dispersive X-ray spectroscopy, and the ions of alkali metal or alkaline earth metal contained in the zeolite before ion exchange. It can be calculated based on the following formula from the residual amount after exchange and the amount of ion-exchanged metal.

Zeolite can be ion-exchanged, for example, by the following method.
(1) Disperse the zeolite in ion-exchanged water, add a salt of metal ions used for ion exchange so that the amount of metal is 0.8 to 5 equivalents with respect to the number of moles of alumina in the zeolite, and at 60 ° C. for 3 hours. Stir with heating. Since metal ions in zeolite exist to electrically neutralize the monovalent negative charge of aluminum, the number of moles of metal salt added is calculated based on the number of moles of aluminum in the zeolite. To do.
(2) The zeolite is sufficiently washed with ion-exchanged water and then filtered.
(3) Heat and dry at 150 ° C. for 12 hours or more to remove water adhering to the zeolite surface. Heat drying is preferably performed under vacuum.

The content of zeolite is preferably 5 to 40% by mass, more preferably 8 to 35% by mass, based on the total mass of the gas adsorbent. If the zeolite content is 5% by mass or more, the gas can be sufficiently adsorbed. When the content is 40% by mass or less, the exposed area of the zeolite becomes a moderate size, and it is possible to avoid the problem that water is adsorbed on the zeolite before calcium oxide and the gas adsorption capacity of the zeolite is reduced. .

The average particle size of zeolite is preferably 1 to 25 μm, more preferably 3 to 10 μm. If the average particle diameter is in the above range, when the gas adsorbent of the present invention is molded, the zeolite is easily dispersed homogeneously in the gas adsorbent, and the total surface area of the zeolite is also increased. Adsorption ability can be fully exhibited. The average particle diameter of zeolite can be measured according to JIS Z 8823.

The zeolite used in the present invention is known and can be easily obtained in the market or can be prepared.

Calcium oxide The calcium oxide in the present invention adsorbs moisture and carbon dioxide.
The calcium oxide used in the present invention is not particularly limited, but the average particle size is preferably 30 to 70 μm, more preferably 35 to 55 μm. The average particle diameter of calcium oxide can be measured according to JIS Z 8823. The average particle diameter of calcium oxide also affects the porosity of the gas adsorbent described later, and if it is 30 μm or more, a gas adsorbent having a desired porosity can be obtained, and the gas adsorbent has sufficient adsorption activity. Have When the average particle diameter is 70 μm or less, the strength of the gas adsorbent can be improved when compression molding, and handling becomes easier.

The content of calcium oxide is preferably 35 to 90% by mass, more preferably 45 to 85% by mass, based on the total mass of the gas adsorbent. When the content of calcium oxide is within this range, moisture adsorption capacity is exhibited in vacuum insulation materials, vacuum insulation structures, or vacuum glass sashes while preventing moisture adsorption on zeolite in the production process of vacuum insulation materials, etc. can do.

Calcium oxide is known and can be easily obtained or prepared on the market.

Binder The binder in the present invention is calcium silicate or magnesium silicate. The binder adsorbs moisture in the air at the time of compression molding or before and after that, and expresses the function as a binder. By adhering zeolite and calcium oxide appropriately, the porosity of the gas adsorbent is in a desired range. Used for. Moreover, the strength and handleability of the gas adsorbent are improved by the close contact of zeolite and calcium oxide.

Examples of the calcium silicate include synthesized calcium silicate and natural minerals containing calcium silicate, such as cements such as Portland cement, fly ash cement, and alumina cement, calcium silicate minerals such as wollastonite and tobermorite, and grossular. , Zoisite, Clinozoite, Lawsonite, Gehlenite, Planenite, Anorsite, Scolesite, Epistibite, Laumonite, Meionite, and other calcium calcium silicate minerals, etc. The tobermorite is more preferable in controlling the porosity of the gas adsorbent.

Examples of magnesium silicate include natural minerals containing magnesium silicate, such as magnesium silicate minerals such as sepiolite, attapulgite, talc, forsterite, humite, enstatite, clinoenstatite, and chrysotile, orlmanite, magnesia axinite, diolite. Examples thereof include magnesium calcium silicate minerals such as psite and tremolite, and needle-shaped sepiolite, attapulgite, and plate-like talc are more preferable for controlling the porosity.

The content of the binder is preferably 5% by mass to 25% by mass and more preferably 8% by mass to 20% by mass with respect to the total mass of the gas adsorbent. When the content of the binder is within this range, the porosity of the adsorbent can be set to a desired range when compression molding is performed, and the gas adsorbent functions sufficiently.

The average particle size of the binder used in the present invention is preferably 5 to 80 μm, more preferably 8 to 70 μm. The average particle diameter of the binder can be measured according to JIS Z 8823. When the binder has a needle-like or plate-like shape, the average particle diameter refers to the average length of the long sides. The average particle size of the binder also affects the porosity of the gas adsorbent described later, and if it is in the above range, a gas adsorbent having a desired porosity can be obtained. The strength of the gas adsorbent can be improved, and handling becomes easy.

The gas adsorbent of the present invention may contain clay minerals containing sodium such as kaolinite, smectite, sericite, illite, chlorite as an extender in addition to zeolite, calcium oxide and binder.

The porosity of the gas adsorbent of the present invention is 40 to 80%, preferably 45 to 75%.
The porosity can be obtained by the following equation from the ratio of the apparent density of the molded gas adsorbent to the true density of the mixture calculated based on the true density and composition ratio of each material.

When the porosity is in the above range, the zeolite has an appropriate exposed area, the gas adsorbent exhibits a sufficient adsorption function, and the adsorption capacity does not deteriorate during long-term use.

The gas adsorbent of the present invention is resistant to temperatures up to sintering, for example, up to about 900 ° C. Therefore, it can be dried by heating at a temperature of, for example, 300 ° C. to 600 ° C. before use, and can be used in a state having a low water content.

The gas adsorbent of the present invention has a high gas adsorbing ability. The gas adsorption capacity of the gas adsorbent can be evaluated based on, for example, the thermal conductivity of the vacuum heat insulating material including the gas adsorbent. If the gas adsorption capacity of the gas adsorbing material is high, the vacuum degree of the vacuum heat insulating material can be kept high, and the thermal conductivity of the vacuum heat insulating material becomes low. For example, it is preferable that the thermal conductivity of the vacuum heat insulating material measured by a heat flow meter method at 20 ° C. according to JIS A1412 immediately after the manufacture of the vacuum heat insulating material including the gas adsorbing material is 0.002 W / mK or less. More preferably, it is 0.0016 W / mK or less. Moreover, after manufacturing the vacuum heat insulating material containing the gas adsorbent, after leaving it to stand in a 90 ° C. dryer for 30 days, the thermal conductivity of the vacuum heat insulating material measured by a heat flow meter method at 20 ° C. according to JIS A1412 0.004 W / mK or less is preferable, and 0.0035 W / mK or less is more preferable.

Although there is no restriction | limiting in particular in the shape of the gas adsorption material of this invention, Preferably, it is plate shape, cylindrical shape, cube shape, spherical shape, cone shape, pyramid shape, etc. If the shape is thin plate and cylinder, it can be accommodated without causing irregularities on the surface of the vacuum heat insulating material.
The magnitude | size of a gas adsorbent can be suitably set according to a use. For example, the size is preferably 0.05 to 5% by volume, more preferably 0.08 to 3% by volume of the total volume of the vacuum part such as a vacuum heat insulating material, a vacuum heat insulating structure, or a vacuum glass sash. It is more preferable that the size becomes.

The gas adsorbent of the present invention is excellent in handleability. The handleability means that the gas adsorbent is inserted and mounted when manufacturing a vacuum heat insulating material, a vacuum heat insulating structure, a vacuum glass sash or the like, and has a bending strength that does not cause breakage or chipping by manual handling. The bending strength of the gas adsorbent can be evaluated according to JIS K7171. The bending strength of the gas adsorbent is preferably from 0.1 to 1.0 MPa, more preferably from 0.2 MPa to 0.6 MPa. If the bending strength of the gas adsorbent is within this range, the handleability of the gas adsorbent is improved without lowering the porosity of the gas adsorbent.

Manufacturing method of gas adsorbent The gas adsorbent of the present invention includes the following steps: a step of mixing zeolite, calcium oxide and a binder without adding water, and a step of compression molding the mixture ,
Wherein the zeolite is ion exchanged with one or more metal ions selected from the group consisting of copper, silver, gold, iron, zinc and nickel ions, The average pore diameter is 0.3 to 1.3 nm, the binder is calcium silicate or magnesium silicate, and the porosity of the gas adsorbent is 40 to 80%.

There is no particular limitation on the means for mixing zeolite, calcium oxide and binder. For example, the components may be mixed in a mixing device such as a V-shaped mixer at a desired mass ratio.
In the mixing process, no water is added. By not adding water, the moisture content of the obtained gas adsorbent can be lowered.

The obtained powdery mixture is filled into a mold such as a mold, and compression molding is performed. Prior to compression molding, the mold may be vibrated to fill the powdery mixture more densely, preferably in a close-packed state.

Molding conditions such as molding temperature, molding pressure and molding time can be appropriately adjusted according to the binder amount or the porosity of the gas adsorbent.
The molding temperature is preferably 10 to 40 ° C., more preferably 15 to 35 ° C., and still more preferably room temperature (25 ° C.). When the molding temperature is in the above range, a gas adsorbent excellent in handleability can be molded.
A preferable molding pressure is 50 to 200 MPa, and more preferably 75 to 125 MPa. When the molding pressure is in the above range, a gas adsorbent having a porosity in the range targeted by the present invention can be molded.
A preferable molding time is 5 to 25 seconds, and more preferably 8 to 20 seconds. When the molding time is in the above range, a gas adsorbent having a porosity in the range targeted by the present invention can be molded.

Vacuum heat insulating material The gas adsorbent of the present invention is used in vacuum heat insulating materials used in refrigerators and vending machines, vacuum heat insulating structures used in refrigeration tank trucks and machinery, vacuum glass sashes for residential buildings, etc. Preferably, it is used for a vacuum heat insulating material. The vacuum heat insulating material includes a core material, a packaging bag, and a gas adsorbing material as components, and the core material and the gas adsorbing material are filled in the packaging bag and vacuum packaged.

Core material A core material is a member which bears the heat insulation of a vacuum heat insulating material, and consists of an inorganic fiber mat.
The inorganic fiber is a fiber made of an inorganic substance, and examples thereof include glass fiber (glass wool, etc.), ceramic fiber, metal fiber and the like. Moreover, slag fiber, basalt fiber (rock wool, basalt fiber), etc. can also be used. In these, the glass fiber and basalt fiber which are excellent in heat insulation and moldability are preferable. Specifically, glass wool, rock wool or the like generally used as a heat insulating sound absorbing material can be preferably used.

The inorganic fiber preferably has an average fiber diameter of 3 to 7 μm. If an average fiber diameter is 3 micrometers or more, manufacture and acquisition of an inorganic fiber will become easy. If an average fiber diameter is 7 micrometers or less, the heat insulation performance required as a core material can be obtained.

The method for producing the inorganic fiber is not particularly limited, and examples thereof include a centrifugal method. By using the centrifugal method, for example, inorganic fibers such as glass fibers (glass wool, etc.), slag fibers, basalt fibers (rock wool, etc.) can be produced.

The inorganic fiber mat refers to an aggregate (web) in which inorganic fibers are accumulated regardless of the thickness and density. The core material may be a single layer made of one inorganic fiber mat or a laminate in which 2 to 4 inorganic fiber mats are laminated.

The density of the core material (density in a vacuum packaged state) is not particularly limited, but is preferably 150 to 250 kg / m ³ . Since the core material having a density of 150 kg / m ³ or more is excellent in compression resistance, the heat insulation performance is hardly lowered due to an increase in the core material density, and the heat insulation performance is excellent. Moreover, since the said core material has moderate rigidity, in addition to being easy to fill the inside of a packaging bag, workability | operativity at the time of installing a vacuum heat insulating material in a heat insulation box becomes favorable. Furthermore, since the said core material has moderate rigidity, it can obtain a vacuum heat insulating material with high dimensional accuracy and high performance of maintaining the shape. Therefore, when the vacuum heat insulating material is installed in the heat insulating box, a gap is hardly generated between the heat insulating box and high heat insulating performance can be exhibited. In order to obtain the effect more reliably, the density is more preferably 180 kg / m ³ or more. On the other hand, by setting the density to 250 kg / m ³ or less, an appropriate gap is maintained between the inorganic fibers constituting the core material, the inorganic fibers do not contact each other excessively, and the heat insulation performance can be improved. Moreover, since moderate flexibility and softness can be imparted to the core material, unevenness (a large number of convex portions) is hardly formed on the surface of the vacuum heat insulating material. Therefore, the vacuum heat insulating material can be installed with no gap with respect to the heat insulating box or the like, and heat insulation defects are hardly generated. In order to obtain the effect more reliably, the density is further preferably set to 220 kg / m ³ or less.

The thickness of the core material (thickness in a vacuum packaged state) is not particularly limited, but is preferably 5 mm or more and 30 mm or less. The heat insulating performance of the vacuum heat insulating material is determined by the thickness of the core material and the thermal conductivity. Therefore, in addition to the low thermal conductivity of the core material, the heat insulation performance can be enhanced by setting the thickness of the core material to a certain value or more. From such a point of view, by setting the thickness to 5 mm or more, high heat insulation performance can be obtained, and design of heat insulation performance can be facilitated. On the other hand, by setting the thickness to 30 mm or less, the workability when installing the vacuum heat insulating material in the heat insulating box is improved, and the work of bonding the vacuum heat insulating material to the heat insulating box becomes easy. Moreover, required heat insulation can be provided, suppressing the manufacturing cost of a core material.

As described above, the inorganic fiber mat may be simply an inorganic fiber accumulated, but is preferably an inorganic fiber mat provided with a thermosetting resin derived from an organic binder. Such an inorganic fiber mat has an appropriate rigidity and is not easily crushed, so that the core material density is hardly increased. Therefore, the heat insulation performance is hardly lowered due to the increase in heat conduction between the inorganic fibers.

The type of the organic binder is not particularly limited, but a precursor capable of forming a polymer by dehydration condensation can be suitably used. Examples of the polymer formed by dehydration condensation include aldehyde condensable resins, polyesters, polyamides, and the like. Examples of the aldehyde condensable resin include a resol type phenol resin, a melamine resin, a benzoguanamine resin, an acetoguanamine resin, a urea resin, and a furan resin. Among these, a resol type phenol resin is preferable.

Therefore, as the organic binder, precursors that can form these polymers (thermosetting resins), for example,
A mixture of formaldehyde and phenol (a precursor of a resole phenolic resin);
A mixture of a polycarboxylic acid and at least one substance selected from the group of polyols (including saccharides), aminoalcohols, iminoalcohols and polyamines (polyesters, polyamide precursors);
Etc. are preferably used. Among these, it is more preferable to use an aqueous binder containing these as components.

As the mixture of formaldehyde and phenol, it is preferable to use a formaldehyde / phenol molar ratio of 2.5 or more and 3.5 or less. When the molar ratio is 2.5 or more, unreacted free phenol can be reduced. On the other hand, when the molar ratio is 3.5 or less, unreacted free formaldehyde can be reduced.

As the mixture of polycarboxylic acid / polyol, etc., those having a molar ratio of (the total number of moles of hydroxyl group, amino group and imino group) / number of moles of carboxyl groups, such as polyol, are 0.5 or more and 1.2 or less. It is preferable. When the molar ratio is 0.5 or more, most of the molecules constituting the binder can participate in the curing reaction, and unreacted free polycarboxylic acid can be reduced. In order to obtain the effect more reliably, the molar ratio is more preferably 0.7 or more. On the other hand, when the molar ratio is 1.2 or less, unreacted free polyol and the like can be reduced. In order to obtain the effect more reliably, the molar ratio is more preferably 1.1 or less. In addition, by reducing unreacted free polycarboxylic acid, unreacted free polyol, etc., these substances gasify over time in the vacuum heat insulating material (outgas), and the heat insulation property of the vacuum heat insulating material is increased by the outgas. The malfunction which falls can be prevented effectively.

The content of the thermosetting resin in the core material is preferably 0.5% by mass or more and 5.0% by mass or less with respect to the total mass of the inorganic fibers and the thermosetting resin. By setting the content to 0.5% by mass or more, the rigidity of the core material is increased, and the core material is not easily crushed during vacuum packaging. In addition, the core material is less likely to sag, and handling properties such as transportation of the core material and filling of the packaging bag are improved. In order to acquire the said effect more reliably, it is still more preferable that the said content rate shall be 1.0 mass% or more. On the other hand, when the content is 5.0% by mass or less, the heat insulation performance is hardly lowered due to the heat conduction of the thermosetting resin. Moreover, generation | occurrence | production of the outgas originating in the said thermosetting resin is suppressed, and the fall of the heat insulation performance resulting from the said outgas does not occur easily. In order to acquire the said effect more reliably, it is still more preferable that the said content rate shall be 3.0% or less. In addition, the content rate of a thermosetting resin is calculated based on the ignition loss measured by the ignition loss method (LOI: Loss of Ignition). The loss on ignition is measured by measuring the mass reduced by igniting a dried sample of the mat-like material to which the organic binder has been adhered and dried at about 550 ° C.

Packaging Bag The packaging bag is a bag made of a gas barrier sheet material. By the packaging bag, the vacuum state inside the bag body is maintained, and the inflow of moisture and gas into the bag body can be prevented.

The type of sheet material is not particularly limited as long as it has gas barrier properties. For example,
Resin films made of resins such as polyester, polyethylene, polyamide, polyvinyl chloride, polyvinylidene chloride, polystyrene, polypropylene;
Laminated film in which the surface of kraft paper is coated with the resin film;
A laminated film in which the surface of the metal foil is coated with the resin film;
A metal-deposited film in which a metal is deposited on the resin film;
Etc. can be used suitably. As said metal foil and the metal for vapor deposition, the aluminum which is excellent in gas barrier property is preferable. Depending on the application, a composite film in which one side of the vacuum heat insulating material is a metal foil film and the other side is a vapor deposition film can be used.

The sheet material includes a laminated sheet in which the sheet materials are laminated. Among these, a laminated sheet having a protective film as the outermost layer, a gas barrier film as the intermediate layer, and a fusible film as the innermost layer is preferable. For example, the protective film is composed of a polyamide resin film or a polyethylene terephthalate resin film, the gas barrier film is composed of an aluminum foil, an aluminum foil laminate film, or an aluminum vapor deposition film, and the fusible film is a low-density polyethylene. A laminated sheet composed of a resin film, a high-density polyethylene resin film, a polypropylene resin film, or an ethylene-vinyl alcohol copolymer resin film can be suitably used. The fusible film is disposed in the innermost layer of the laminated sheet for the purpose of fusing the peripheral edges of the sheet material.
Although the thickness of each film which comprises a lamination sheet is not specifically limited, It is preferable that the thickness of a protective film and the thickness of a gas barrier film are 10 micrometers or more and 25 micrometers or less. By making the thickness 10 μm or more, the packaging bag can be effectively prevented from being damaged. On the other hand, when the thickness is 25 μm or less, the thermal bridge (heat bridge) of the packaging bag can be reduced.

The thickness of the fusible film is preferably 25 μm or more and 60 μm or less. By setting the thickness to 25 μm or more, it is possible to improve the sealing performance of the fused portion where the fusible films are fused together, and it is difficult for leakage from the fused portion to occur after vacuum packaging. . In order to obtain the effect more reliably, the thickness is further preferably set to 30 μm or more. On the other hand, when the thickness is 60 μm or less, the thermal bridge (heat bridge) of the packaging bag can be reduced. In order to obtain the effect more reliably, the thickness is more preferably 50 μm or less.

It should be noted that the size of the packaging bag is not particularly limited as long as it is configured to be a size that can be filled with the core material.

Degree of vacuum The vacuum heat insulating material of the present invention is obtained by filling the inside of the packaging bag with the core material and the gas adsorbing material and vacuum-packaging them. The degree of vacuum inside the packaging bag (residual gas pressure) is preferably 0.1 Pa or more and 10 Pa or less. As the degree of vacuum is lowered, the heat insulation performance of the obtained vacuum heat insulating material is improved, but the time required for vacuum packaging is increased correspondingly, and the productivity is lowered. By setting the degree of vacuum to 0.1 Pa or more, the time required for evacuation is shortened, and a vacuum heat insulating material can be efficiently manufactured. On the other hand, when the degree of vacuum is 10 Pa or less, a sufficient heat insulating effect as a vacuum heat insulating material is exhibited. In order to obtain the effect more reliably, the degree of vacuum is more preferably 5 Pa or less.

Manufacturing method of vacuum heat insulating material The vacuum heat insulating material of the present invention may be manufactured by any manufacturing method as long as it has the above configuration. Hereinafter, the example of the manufacturing method of the vacuum heat insulating material of this invention is shown.

Production of inorganic fiber mat The production method of the inorganic fiber mat is not particularly limited. First, in the fiberizing step of spinning inorganic fibers, fiberization is performed by a centrifugal method (rotary method), a spinning method, or the like. The fiberization by the centrifugal method is preferable from the viewpoint of economy.
Next, an organic binder is applied to the spun inorganic fibers by a spray method.
Furthermore, the inorganic fiber to which the organic binder has been applied is heated and molded (matting step). Inorganic fibers to which an organic binder has been applied are accumulated on a mesh belt conveyor disposed below the fiberizing apparatus and conveyed to a hot air oven. And inorganic fiber is sent between conveyors and compressed to predetermined thickness. The compressed inorganic fiber is heated when it passes through the hot air oven, and the attached organic binder is thermally cured. By such a process, an inorganic fiber mat in which inorganic fibers are formed into a mat shape can be produced.

In the matting step, the heating temperature is preferably 150 to 300 ° C., and the heating time is preferably 60 to 300 seconds. By setting the heating temperature to 150 ° C. or more and the heating time to 60 seconds or more, the organic binder can be sufficiently cured by heat. Therefore, unreacted low molecular weight substances that cause outgassing can be reduced, and moisture adhering to the inorganic fiber mat can be reduced. By setting the heating temperature to 300 ° C. or less and 300 seconds or less, decomposition of the thermosetting resin derived from the organic binder can be suppressed, and productivity is improved by not performing excessive heating. Can do.

The density of the inorganic fiber mat is preferably 32 kg / m ³ or more and 100 kg / m ³ or less. By setting the density to 32 kg / m ³ or more, a certain rigidity is imparted, and handling properties when filling the packaging bag are improved. In order to obtain the effect more reliably, the density is more preferably 48 kg / m ³ or more. On the other hand, by setting it as 100 kg / m < ³ > or less, the density increase of the core material in the case of vacuum packaging and the time-dependent fall of heat insulation performance can be suppressed. In order to obtain the effect more reliably, the density is more preferably 90 kg / m ³ or less.

The thickness of the inorganic fiber mat is preferably 10 mm or more and 50 mm or less. By making the thickness 10 mm or more, the mat can be easily manufactured. In order to obtain the effect more reliably, the thickness is more preferably 25 mm or more. On the other hand, the handling property at the time of filling a packaging bag improves by making the said thickness into 50 mm or less. In order to obtain the effect more reliably, the thickness is further preferably set to 45 mm or less.

The inorganic fiber mat may be removed by heating and forced drying before vacuum packaging to remove water adhering to the inorganic fibers. Forced drying can be performed using, for example, a far-infrared oven or a hot air oven. The heating temperature is not particularly limited, but is preferably 130 ° C. or higher and more preferably 150 ° C. or higher in order to quickly remove moisture.

Vacuum packaging Finally, the core material and the gas adsorbent are filled in a packaging bag and vacuum packaged. Vacuum packaging can be performed according to a conventionally known method. For example, a method of filling the inside of the core material and the gas adsorbing material and then evacuating the inside of the packaging bag until the degree of vacuum becomes 0.1 to 10 Pa, and heat-sealing the opening of the packaging bag, etc. Can be mentioned.

Further, the core material and the gas adsorbing material are not filled in a bag formed in advance in a bag shape, but the core material and the gas adsorbing material are sandwiched between two upper and lower gas barrier sheet materials, and the two sheets The sheet material may be fused to form a packaging bag made of the sheet material, and the core material and the gas adsorbing material may be filled into the packaging bag.
The gas adsorbent is preferably dried for 3 to 12 hours under a temperature condition of 300 to 600 ° C. before vacuum packaging. The gas barrier sheet material is preferably dried at a temperature of 50 to 100 ° C. for 60 to 120 minutes before filling the core material. By these drying, the moisture adsorbed on the gas adsorbing material and the packaging bag is removed, and the moisture can be prevented from being mixed into the obtained vacuum heat insulating material. Therefore, it becomes possible to improve the heat insulation of a vacuum heat insulating material.

Vacuum insulation can be used for refrigerators, vending machines, refrigerated tank trucks, mechanical equipment, vacuum glass sashes for residential buildings, and the like.

Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the examples.

Example 1
10 parts by mass of Y-zeolite with an average pore diameter of 1.1 nm (ion exchange rate 85%, average particle diameter 5 μm) ion-exchanged with copper, 80 parts by mass of calcium oxide with an average particle diameter of 45 μm, and an average length of 17 μm on the long side 10 parts by mass of plate-like tobermorite was put into a V-type mixer and dry-mixed to obtain a gas adsorption mixture. The above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and the gas adsorbent 1 was obtained by pressing with a press machine at 100 MPa for 10 seconds without heating in an environment of 25 ° C. The porosity of the gas adsorbent 1 was 55%.
Gas barrier property formed by laminating polyethylene (density 0.94 g / cm ³ , thickness 50 μm), aluminum foil (thickness 6.5 μm), polyethylene terephthalate (thickness 12 μm) and polyamide (thickness 25 μm) in this order. Two sheets of film (total thickness 100μm including urethane adhesive) are stacked so that the polyethylene layers are in contact with each other, and the outer periphery is heat-sealed, leaving an opening for insertion of the core material. Formed.
Glass fiber mat (average fiber diameter 7 μm, thickness 45 mm, density 64 kg / m ³ , binder resin adhesion 1.4%, phenol-formaldehyde resin binder (formaldehyde / phenol molar ratio 3.0) hot air at 180 ° C. Were cured for 2 minutes and then molded) and dried at 150 ° C. for 30 minutes to obtain a core material.
Insert the core material and gas adsorbent 1 into the bag-shaped outer shell material, place it in the vacuum packaging machine, depressurize the vacuum packaging machine with a Penning vacuum gauge until a measured value of 2 Pa is obtained, heat seal it, and open the outer shell material. The part was sealed and the vacuum heat insulating material of Example 1 which has an ear | edge part was obtained. Vacuum insulation material after folding ear, vertical 670 mm, horizontal 390 mm, a size of a thickness of 15 mm, the core density was 210 kg / m ^3.

Example 2
30 parts by mass of Y-zeolite having an average pore diameter of 1.1 nm (ion exchange rate 82%, average particle diameter 5 μm) ion-exchanged with copper, 50 parts by mass of calcium oxide having an average particle diameter of 45 μm, and an average length of 17 μm on the long side 20 parts by mass of plate-like tobermorite was put into a V-type mixer and dry-mixed to obtain a gas adsorption mixture. The gas adsorbent 2 was obtained except that the above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and was pressed at 100 MPa for 10 seconds with a press machine without heating in an environment of 25 ° C. In the same manner as in Example 1, a vacuum heat insulating material of Example 2 was obtained. The porosity of the gas adsorbent 2 was 55%.

Example 3
10 parts by mass of Y-zeolite having an average pore diameter of 1.1 nm (ion exchange rate of 93%, average particle diameter of 5 μm) ion-exchanged with silver, 80 parts by mass of calcium oxide having an average particle diameter of 45 μm, and an average length of 65 μm on the long side Ten parts by mass of acicular wollastonite was put into a V-type mixer and dry-mixed to obtain a gas adsorption mixture. The gas adsorbent 3 was obtained except that the above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and pressed at 100 MPa for 15 seconds with a press machine without heating in an environment of 25 ° C. The vacuum heat insulating material of Example 3 was obtained in the same manner as Example 1. The porosity of the gas adsorbent 3 was 46%.

Example 4
ZSM-5 zeolite with an average pore size of 0.5 nm ion-exchanged with copper (ion exchange rate 82%, average particle size 6 μm, zeolite Na ⁺ ₃₉ (H ₂ O) ₁₆ | [Al ₃₉ Si ₅₇ O before ion exchange) ₁₉₂ ]) 10 parts by mass, 80 parts by mass of calcium oxide having an average particle diameter of 45 μm and 10 parts by mass of Portland cement having an average particle diameter of 10 μm were put into a V-type mixer and dry-mixed to obtain a gas adsorption mixture. The above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and was pressed at 100 MPa for 10 seconds with a press machine without heating in an environment of 25 ° C. to obtain a gas adsorbent 4. The porosity of the gas adsorbent 4 was 57%.

Polyethylene (density 0.94 g / cm ³ , thickness 50 μm), aluminum-deposited ethylene-vinyl alcohol copolymer film (thickness 12 μm), aluminum-deposited polyethylene terephthalate (thickness 12 μm) and polyamide (thickness 15 μm) are laminated in this order. 2 gas barrier films (total thickness 105 μm including urethane adhesive) are stacked so that the polyethylene layers are in contact with each other, leaving an opening for inserting the core material Was heat sealed to form a bag.
Glass fiber mat (average fiber diameter 7 μm, thickness 45 mm, density 64 kg / m ³ , binder resin adhesion 1.4%, phenol-formaldehyde resin binder (formaldehyde / phenol molar ratio 3.0) hot air at 180 ° C. Were cured for 2 minutes and then molded) and dried at 150 ° C. for 30 minutes to obtain a core material.
Insert the core material and gas adsorbing material 4 into the bag-shaped outer shell material, place it in the vacuum packaging machine, depressurize the vacuum packaging machine with a Penning vacuum gauge until a measured value of 2 Pa is obtained, heat seal and open the outer skin material The part was sealed and the vacuum heat insulating material of Example 4 which has an ear | edge part was obtained. The vacuum heat insulating material after the ear folding was 670 mm long, 390 mm wide and 15 mm thick, and the core material density was 210 kg / m ³ .

Example 5
10 parts by mass of Y-zeolite having an average pore size of 1.1 nm ion-exchanged with copper (93% ion exchange rate, average particle size 5 μm), 80 parts by mass of calcium oxide having an average particle size of 45 μm, and an average length of 50 μm on the long side Ten parts by mass of needle-shaped sepiolite was put into a V-type mixer and dry-mixed to obtain a gas adsorption mixture. The gas adsorbent 5 was obtained except that the above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and pressed at 100 MPa for 15 seconds with a press machine without heating in an environment of 25 ° C. In the same manner as in Example 1, a vacuum heat insulating material of Example 5 was obtained. The porosity of the gas adsorbent 5 was 48%.

Comparative Example 1
10 parts by mass of Y-zeolite having an average pore diameter of 1.1 nm (ion exchange rate 82%, average particle diameter 5 μm) ion-exchanged with copper and 90 parts by mass of calcium oxide having an average particle diameter of 45 μm were put into a V-type mixer, Dry mixing was performed to obtain a gas adsorption mixture. The above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and was pressed at 100 MPa for 10 seconds with a press machine without heating in an environment of 25 ° C. to obtain a gas adsorbent 6. The porosity of the gas adsorbent 6 was 38%.
In the same manner as in Example 1, a vacuum heat insulating material of Comparative Example 1 was obtained.

Comparative Example 2
100 parts by mass of calcium oxide having an average particle size of 45 μm is filled into a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and is pressed at 100 MPa for 10 seconds by a press machine without heating in an environment of 25 ° C. Adsorbent 7 was obtained. The porosity of the gas adsorbent 7 was 35%.
In the same manner as in Example 1, a vacuum heat insulating material of Comparative Example 2 was obtained.

Comparative Example 3
90 parts by mass of Y-zeolite having an average pore diameter of 1.1 nm (ion exchange rate of 85%, average particle diameter of 5 μm) ion-exchanged with copper and 10 parts by mass of tobermorite of plate-like crystals having an average long side of 17 μm in average length The mixture was put into a mold mixer and dry-mixed to obtain a gas adsorption mixture. The above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and was pressed at 100 MPa for 10 seconds with a press machine without heating in an environment of 25 ° C. to obtain a gas adsorbent 8. The porosity of the gas adsorbent 8 was 75%.
In the same manner as in Example 1, a vacuum heat insulating material of Comparative Example 3 was obtained.

Comparative Example 4
ZSM-5 type zeolite (average particle size 6 μm, Na ⁺ ₃₉ (H ₂ O) ₁₆ | [Al ₃₉ Si ₅₇ O ₁₉₂ ]) 10 parts by mass, average particle size 45 μm 80 parts by mass of calcium oxide and 10 parts by mass of Portland cement having an average particle diameter of 10 μm were put into a V-type mixer and dry-mixed to obtain a gas adsorption mixture. The above mixture was filled in a cylindrical mold having an inner diameter of 30 mm and a depth of 5 mm, and was pressed at 100 MPa for 10 seconds with a press machine without heating in an environment of 25 ° C. to obtain a gas adsorbent 9. The porosity of the gas adsorbent 9 was 55%.
In the same manner as in Example 1, a vacuum heat insulating material of Comparative Example 4 was obtained.

Evaluation Example 1
The thermal conductivity at 20 ° C. of the vacuum heat insulating materials of Examples 1 to 4 and Comparative Examples 1 to 4 was measured by a heat flow meter method according to JIS A1412.

Evaluation example 2
The vacuum heat insulating materials of Examples 1 to 4 and Comparative Examples 1 to 4 were allowed to stand in a dryer at 90 ° C. for 30 days, and then the thermal conductivity at 20 ° C. was measured by a heat flow meter method according to JIS A1412. did.

The gas adsorbent of the present invention is useful in application to vacuum heat insulating materials used in refrigerators and vending machines, vacuum heat insulating structures used in refrigeration tank trucks and machinery, vacuum glass sashes for residential buildings, and the like.

Claims

A gas adsorbent containing zeolite, calcium oxide, and a binder,
The zeolite is ion-exchanged with one or more metal ions selected from the group consisting of copper, silver, gold, iron, zinc and nickel ions;
The zeolite has an average pore diameter of 0.3 to 1.3 nm,
The binder is calcium silicate or magnesium silicate;
The gas adsorbent has a porosity of 40 to 80%.
A gas adsorbent characterized by that.
The gas adsorbent according to claim 1, wherein the binder is calcium silicate.
The gas adsorbent according to claim 2, wherein the calcium silicate is dobermorite, wollastonite, or Portland cement.
The gas adsorbent according to claim 1, wherein the binder is magnesium silicate.
The gas adsorbent according to claim 4, wherein the magnesium silicate is sepiolite, attapulgite or talc.
The gas adsorbent according to any one of claims 1 to 5, wherein a content of the binder is 5% by mass to 25% by mass with respect to a total mass of the gas adsorbent.
The gas adsorbent according to any one of claims 1 to 6, wherein the metal ions are at least one selected from the group consisting of copper, silver, iron and nickel ions.
The ion exchange rate in the zeolite is 40 to 120 mol% with respect to the total number of moles of alkali metal and alkaline earth metal contained in the zeolite before ion exchange, according to any one of claims 1 to 7. The gas adsorbent described.
The gas adsorbent according to any one of claims 1 to 8, wherein a content of the zeolite is 5 mass% to 40 mass% with respect to a total mass of the gas adsorbent.
The gas adsorbent according to any one of claims 1 to 9, which is a compression molded product.
The gas adsorbent according to any one of claims 1 to 10, which is used for a vacuum heat insulating material.
A gas adsorbent according to any one of claims 1 to 11, a core material made of an inorganic fiber mat, and a packaging bag made of a gas barrier sheet material enclosing the gas adsorbent and the core material. Including vacuum insulation.
A method for producing a gas adsorbent, comprising:
A step of mixing a zeolite, calcium oxide and a binder without adding water to obtain a mixture, and a step of compression-molding the mixture,
Including
The zeolite is ion-exchanged with one or more metal ions selected from the group consisting of copper, silver, gold, iron, zinc and nickel ions;
The zeolite has an average pore diameter of 0.3 to 1.3 nm,
The binder is calcium silicate or magnesium silicate;
The porosity of the gas adsorbent is 40 to 80%.
A method characterized by that.
The method according to claim 13, wherein the compression molding step is performed at a molding pressure of 50 to 200 MPa.