Glass wool mat manufacturing method

Abstract

The present invention aims to provide a method for manufacturing a glass wool mat that can suppress adhesion of glass wool to manufacturing equipment and stickiness of the manufacturing equipment, even when the glass wool mat has a high binder content (IGLOS), and can perform stable continuous production. [Solution] A method for manufacturing a glass wool mat, comprising: a binder application step of applying an acrylic resin binder to glass wool to obtain glass wool with an uncured binder; a cotton collection step of collecting the glass wool with the uncured binder on a flight conveyor to form a mat and obtain an uncured glass wool mat; a moisture addition step of adding moisture to the uncured glass wool mat to obtain a moisture-added uncured glass wool mat; and a compression heating step of compressing and heating the moisture-added uncured glass wool mat in an oven to obtain a glass wool mat.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a glass wool mat. [Background technology]

[0002] Conventionally, vacuum insulation panels (VIPs) used in insulation boxes have a high density. One factor contributing to this high density is that the inorganic fibers constituting the inorganic fiber mat used as the core material of the vacuum insulation panel have been thinned and the organic binder content (igloss) has been reduced to improve the insulation performance. Efforts have been made to further improve the insulation performance of vacuum insulation panels while making the inorganic fiber mat thin and low-igloss, such as a technology (Patent Document 1) that improves the insulation performance of vacuum insulation panels by aligning the fiber orientation of the inorganic fiber mat perpendicular to the heat transfer direction and smoothing the surface.

[0003] On the other hand, recently, a vacuum insulation material has been developed that enables high igloss by combining and sealing two types of adsorbents, a gas adsorbent and a moisture adsorbent, in the vacuum insulation material, and having the gas adsorbent absorb the outgassing generated from the organic binder, thereby suppressing the deterioration of insulation performance due to outgassing even if the igloss of the inorganic fiber mat is high (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-163212 [Patent Document 2] Patent No. 7454827 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the igloss of the inorganic fiber mat is high as in the vacuum insulation material of Patent Document 2, adhesion of glass wool to the manufacturing equipment and stickiness of the manufacturing equipment increase during the production of the inorganic fiber mat, making continuous production difficult. When a phenolic resin binder is used as the organic binder, its low viscosity allows for a certain degree of continuous production, but its odor makes long-term continuous production a poor working environment.In contrast, acrylic resin binders have almost no odor problems, but their high viscosity causes glass wool to adhere to the manufacturing equipment and makes the manufacturing equipment sticky.

[0006] Therefore, the present invention aims to provide a method for manufacturing glass wool mat that can suppress adhesion of glass wool to manufacturing equipment and stickiness of manufacturing equipment, even for glass wool mats with a high organic binder content (IGLOS), and enable stable continuous production. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have discovered that the above problems can be solved by adding moisture to glass wool, and have thus completed the present invention.

[0008] The present invention is as follows. [1] a binder application step of applying an acrylic resin binder to the glass wool to obtain uncured binder-coated glass wool; A fiber collecting step of collecting the uncured binder-attached glass wool on a flight conveyor to form a mat, thereby obtaining an uncured glass wool mat; A moisture-adding step of adding moisture to the uncured glass wool mat to obtain a moisture-added uncured glass wool mat; a compression heating step of compressing and heating the moisture-containing uncured glass wool mat in an oven to obtain a glass wool mat; A method for producing a glass wool mat, comprising: [2] The method for manufacturing a glass wool mat according to [1], wherein in the moisture adding step, moisture is directly added to the uncured glass wool mat. [3] The method for manufacturing a glass wool mat according to [1] or [2], wherein in the moisture imparting step, moisture is indirectly imparted to the uncured glass wool mat. [4] The method for producing a glass wool mat according to any one of [1] to [3], wherein the glass wool mat has an Igros content of 4.0 to 8.0 mass % in terms of solid content. [5] In the moisture application step, the amount of moisture applied per unit area to the uncured glass wool mat is 0.008 to 0.070 L / m 2 The method for producing a glass wool mat according to any one of [1] to [4], wherein [6] The method for manufacturing a glass wool mat according to any one of [1] to [5], further comprising a pressurizing step of pressing the moisture-added uncured glass wool mat with a press roll simultaneously with or after the moisture-adding step and before the compression and heating step. [7] The method for producing a glass wool mat according to any one of [1] to [6], wherein the glass wool mat is used as a core material for a vacuum insulation material. [Effects of the Invention]

[0009] According to the present invention, a method for manufacturing glass wool mat can be provided that can suppress adhesion of glass wool to manufacturing equipment and stickiness of manufacturing equipment, even for glass wool mats with a high binder content (igloss), and can enable stable continuous production. [Brief explanation of the drawings]

[0010] [Figure 1] 1A and 1B are diagrams illustrating the moisture-adding step and the compression-heating step of the glass wool mat manufacturing method of the examples. (A) corresponds to Examples 1 and 2, (B) to Example 3, (C) to Example 4, and (D) to Example 5. [Figure 2] FIG. 2 is a diagram illustrating the moisture-adding step in the glass wool mat manufacturing method of Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist thereof.

[0012] [Glass wool mat manufacturing method] The method for manufacturing a glass wool mat of this embodiment is characterized by including a binder application step of applying an acrylic resin binder to glass wool to obtain glass wool with an uncured binder, a cotton collection step of collecting the glass wool with the uncured binder on a flight conveyor to form a mat and obtain an uncured glass wool mat, a moisture application step of applying moisture to the uncured glass wool mat to obtain a moisture-added uncured glass wool mat, and a compression heating step of compressing and heating the moisture-added uncured glass wool mat in an oven to obtain a glass wool mat. In the method for manufacturing a glass wool mat of this embodiment, by carrying out a moisture addition step, it is possible to easily, inexpensively, and efficiently suppress adhesion of glass wool to manufacturing equipment and stickiness of the manufacturing equipment while minimizing the impact on the performance of products using the glass wool mat (such as vacuum insulation materials).In addition, it is possible to prevent the glass wool on the mat surface from adhering to the manufacturing equipment (clusters of glass wool breaking off), which would impair the surface smoothness of the glass wool mat.

[0013] The method for manufacturing a glass wool mat of this embodiment may include steps other than those described above, such as a fiberizing step of fiberizing glass to obtain glass wool, a cutting step of cutting the glass wool mat to a desired size after the compression and heating step, a packaging step of packaging the glass wool mat, etc. Also, simultaneously with or after the moisture-adding step, and before the compression and heating step, a pressurizing step of compressing the moisture-added uncured glass wool mat with a press roll may be included.

[0014] [[Fiberization step]] The fiberization step is a step of fiberizing glass to produce glass wool. Glass wool can be produced, for example, by melting glass in a glass melting furnace or the like, followed by heating with gas and air combustion in a fiberization device and stretching the fibers with compressed air in a fiberization device, but is not limited thereto. Examples of fiberization methods include the conventionally known centrifugal method (rotary method), flame method, and blowing method. Among these, the centrifugal method is preferred because it is easy to produce fine fibers. Examples of fiberization devices using the centrifugal method include a spinner.

[0015] [[Binder application step]] The binder application step is a step of applying an acrylic resin binder to the glass wool to obtain glass wool with an uncured binder. The method of applying the acrylic resin binder to the glass wool is not particularly limited, and examples thereof include a method of applying or spraying the acrylic resin binder using a spray device or the like. In order to efficiently and uniformly adhere the acrylic resin binder to the entire glass wool, it is preferable to apply the acrylic resin binder immediately after fiberization of the glass. The concentration of the acrylic resin binder is preferably 5 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 5 to 20% by mass. When the concentration of the acrylic resin binder is within the above range, the acrylic resin binder can be adhered more efficiently and more uniformly to the entire glass wool. The flow rate of the acrylic resin binder (amount sprayed or applied) is preferably 480 to 540 L, more preferably 490 to 530 L, and even more preferably 500 to 520 L per 1000 kg of glass discharged. When the flow rate of the acrylic resin binder is within the above range, the acrylic resin binder can be adhered more efficiently and more uniformly to the entire glass wool. The flow rate of the binder can be changed as needed depending on the amount of glass discharged. The acrylic resin binder is preferably sprayed or applied together with dilution water. The flow rate of the dilution water (amount sprayed or applied) may be appropriately set depending on the flow rate of the acrylic resin binder and the desired gloss. For example, if the amount of acrylic resin binder sprayed or applied is 480 to 540 L per 1,000 kg of glass, the flow rate of the dilution water can be 760 to 860 L.

[0016] [[Cotton collection step]] In the fiber collecting step, the glass wool with uncured binder obtained in the binder application step is collected (piled) on a flight conveyor to form a mat, thereby obtaining an uncured glass wool mat. Air is sucked from above to below the flight (from the side where the glass fibers are collected to the opposite side) through multiple through holes provided in the flight, and the glass wool is collected on the flight. The means for sucking air is not particularly limited, and a suction device such as an exhaust fan can be used.

[0017] [[Moisturizing Step]] The moisture addition step is a step in which moisture is added to the uncured glass wool mat obtained in the fiber collection step to obtain a moisture-added uncured glass wool mat. By adding moisture in the moisture addition step, the acrylic resin binder near the surface of the uncured glass wool mat is diluted, and a water film is formed on the surface of the mat. This water film on the surface prevents the uncured binder-attached glass wool from adhering to equipment or becoming sticky when the uncured glass wool mat comes into contact with equipment such as an oven's compression / heating conveyor or press roll.

[0018] The method for providing moisture is not particularly limited, but from the viewpoint of efficiently and uniformly providing moisture to the entire uncured glass wool mat, it is preferable to spray or apply the moisture using a moisture providing device such as a sprayer. The spray is not particularly limited and may be, for example, a gas-liquid two-fluid nozzle or a single-liquid nozzle, but a single-liquid nozzle is preferred because spraying air from a gas-liquid two-fluid nozzle can cause some of the glass wool to detach from the top surface of the uncured glass wool mat, potentially damaging the surface smoothness of the glass wool mat. Examples of commercially available products include the fine mist-generating two-fluid nozzle BIMV8022 and the small-spray-volume hollow cone nozzle 1 / 4M K 050N S303W manufactured by Ikeuchi Co., Ltd. The arrangement and number of moisture-imparting devices such as sprayers are not particularly limited and may be set appropriately depending on the desired amount of moisture to be added, the size of the uncured glass wool mat, etc. For example, moisture-imparting devices may be installed at multiple locations to add moisture in multiple batches, but from the viewpoint of easy control of the amount of moisture, it is preferable to add moisture at only one location. When the water is applied by spraying, the average particle size of the sprayed water is not particularly limited and may be, for example, 20 to 400 μm, or 10 to 300 μm. When the average particle size of the sprayed water is within the above range, a water film tends to be well formed on the surface of the uncured glass wool mat.

[0019] Furthermore, moisture may be applied directly or indirectly to the uncured glass wool mat. Examples of methods for directly applying moisture include a method in which moisture is sprayed or applied to the upper surface of the uncured glass wool mat as it flows on a transport conveyor. Examples of methods for indirectly applying moisture include a method in which moisture is sprayed or applied to the surface of equipment such as a press roll used in the pressurizing step described below, and the moisture is transferred from the equipment to the uncured glass wool mat.

[0020] The addition of moisture may be carried out while the uncured glass wool mat is flowing on the transport conveyor, in which case moisture may be added only from the top side of the uncured glass wool mat and not from the bottom and / or side sides that are in contact with the transport conveyor, or further, moisture may not be added from the bottom and / or side sides, and moisture added from the top side may not be present on (do not reach) the bottom and / or side. If moisture is added to the top surface of the uncured glass wool mat to form a water film, and stickiness on the top surface and adhesion of glass wool from the top to the manufacturing equipment are reduced, the glass wool adhering to the manufacturing equipment will be prevented from gradually growing larger and falling as clumps onto the uncured glass wool mat due to gravity, leading to stable continuous production. On the other hand, since stickiness on the underside and sides of the uncured glass wool mat and adhesion of the glass wool from the underside and sides to the manufacturing equipment have little impact on continuous production, it is not necessary for moisture to be applied from the underside and / or sides, and it is not necessary for moisture to be applied to the underside and / or sides (there is no applied moisture).

[0021] As the moisture, water such as city water or well water is preferred because it is inexpensive, can be removed by heating in an oven, and is unlikely to affect the performance of products using the glass wool mat (such as vacuum insulation materials). Aqueous solutions containing components other than water (for example, small amounts of surfactants or oils) may also be used, as long as they do not affect the performance of the manufacturing equipment or the glass wool mat products (such as vacuum insulation materials).

[0022] The amount of water to be added to the uncured glass wool mat may be appropriately set in consideration of the moisture content measured periodically, the average temperature and average humidity during production, etc., so that the moisture content of the uncured glass wool mat reaches a desired value. For example, the amount of water per unit area of ​​the uncured glass wool mat is set to 0.008 to 0.070 L / m 2 is preferably 0.020 to 0.070 L / m 2 and more preferably 0.030 to 0.070 L / m 2 When the amount of water added is equal to or greater than the lower limit, a water film is well formed on the surface of the uncured glass wool mat, which tends to better prevent the glass wool from adhering to the manufacturing equipment and the manufacturing equipment from becoming sticky. When the amount of water added is equal to or less than the upper limit, firing proceeds sufficiently in the subsequent compression and heating step, which tends to better reduce the generation of uncured acrylic resin binder. The amount of water to be added can be calculated from the water pressure gauge and nozzle design values ​​attached to the piping of the water-adding device (spray, etc.), and the amount of water can be adjusted by adjusting the water pressure.

[0023] The moisture content of the uncured glass wool mat is preferably 20 to 50%, more preferably 25 to 40%, and even more preferably 30 to 35%. When the moisture content of the uncured glass wool mat is equal to or greater than the lower limit, a water film is effectively formed on the surface of the uncured glass wool mat, which tends to more effectively prevent the glass wool from adhering to the manufacturing equipment and the manufacturing equipment from becoming sticky. Furthermore, when the moisture content is 50% or less, baking in the subsequent compression and heating step proceeds sufficiently to a level that is practically problem-free. When the moisture content is 40% or less, baking proceeds more sufficiently, which tends to more effectively reduce the generation of uncured acrylic resin binder. The moisture content of the uncured glass wool mat can be adjusted by adjusting the amount of moisture added to the uncured glass wool mat, the location of a moisture adding device, and the like. The moisture content of the uncured glass wool mat is a value measured using a moisture meter at a depth of approximately 100 mm from the surface on the side where moisture is applied, and specifically, can be measured by the method described in the examples below.

[0024] [[Pressure step]] The pressurizing step is carried out simultaneously with or after the moisture-imparting step and before the compression and heating step, and is a step in which the moisture-imparted uncured glass wool mat is pressed with a press roll. By compressing the mat in the thickness direction before hardening the acrylic resin binder in the subsequent compression and heating step (before the glass wool fibers bond together), a glass wool mat can be obtained in which the fiber orientation of the glass wool is aligned substantially perpendicular to the thickness direction (horizontally in the planar direction). As a result, when the glass wool mat is used as the core material of a vacuum insulation material, the insulation performance of the vacuum insulation material tends to be improved and stabilized because the fiber orientation of the glass wool is substantially perpendicular to the thickness direction (heat transfer direction). The press roll is not particularly limited, but it is preferable to use a pair of upper and lower press rolls from the viewpoint of productivity. When a pair of upper and lower press rolls is used, pressure is applied uniformly from both sides, which makes it possible to produce a glass wool mat with a more uniform fiber orientation and a smoother surface. The pressure may be appropriately set depending on the desired final density and thickness of the glass wool mat. However, in order to keep the fiber orientation of the glass wool effectively aligned even after the compression and heating step, the density of the uncured glass wool mat with moisture after pressing (however, the moisture is not taken into consideration) should be 160 to 330 kg / m 3 Set it so that

[0025] [[Compression and heating step]] In the compression and heating step, the moisture-added uncured glass wool mat is compressed and heated in an oven to cure the acrylic resin binder, thereby obtaining a glass wool mat. Most of the components in the water and aqueous solution added in the moisture-adding step are removed by heating in this step. The heating conditions are not particularly limited as long as they are sufficient to thermally cure the acrylic resin binder, and the heating temperature can be, for example, 230 to 300°C. The conveyor is not particularly limited as long as it can simultaneously apply pressure and heat, and examples thereof include a hot air passage oven equipped with a pair of upper and lower conveyors inside.

[0026] [[Cutting Steps and Packaging Steps]] The cutting step is a step of cutting the glass wool mat to a desired size. The cutting method is not particularly limited, and a conventionally known method such as a trim saw or a chopper can be used. The packaging step is a step of packaging the glass wool mat. The packaging method is not particularly limited, and a conventionally known method can be used.

[0027] [Glass wool mat] The glass wool mat manufactured by the glass wool mat manufacturing method of this embodiment contains glass wool and an acrylic resin binder. Because the glass wool fibers are fixed together by the acrylic resin binder, the glass wool mat has appropriate rigidity and is not easily crushed, and its density and thermal conductivity between the fibers are not easily increased, making it suitable for use as a core material for vacuum insulation materials, etc.

[0028] [[glass wool]] The glass wool preferably has an average fiber diameter of 2 to 10 μm, more preferably 2.5 to 8 μm, even more preferably 3 to 7 μm, and particularly preferably 3 to 5 μm. When the average fiber diameter of the glass wool is within the above range, it is possible to reduce tearing of the glass wool when the glass wool mat is pressed with a press roll or the like, uneven thickness of the glass wool mat, and skin irritation caused by the glass wool. Furthermore, when the glass wool mat is used as the core material of a vacuum insulation material, it tends to have appropriate strength and excellent heat insulation properties that enable suppression of deterioration over time (increase in thermal conductivity over time). The average fiber diameter of the glass wool can be measured by an airflow resistance method or by using an optical microscope.

[0029] [[Acrylic resin binder]] The acrylic resin binder is not particularly limited, but it is preferable to use a mixture of a polymer having an acrylic group and at least one substance selected from the group consisting of polyols (including sugars), amino alcohols, imino alcohols, and polyamines. Among these, it is preferable to use an aqueous binder containing these components. The acrylic resin binder may contain additives such as a crosslinking agent, a dust suppressant, a color former, a colorant, a pH adjuster, a curing accelerator, a silane coupling agent, and a neutralizing agent for neutralizing alkaline components eluted from the glass wool, as needed, provided that the content does not impair the effects of the present invention. Acrylic resin binders are well known and readily available commercially, and can also be prepared.

[0030] The content of the resin component in the acrylic resin binder may be equivalent to the content of the resin component in an acrylic resin binder that is normally used for glass wool, and may be, for example, 90 to 100 mass % in terms of solid content, assuming that the mass of the acrylic resin binder is 100 mass %. The solid content refers to components that do not volatilize when the acrylic resin binder is heated at 1 atmosphere and at a temperature of room temperature (about 23° C.) or higher and 100° C. or lower. The component other than the solid content (volatile component) is preferably water.

[0031] The acrylic resin binder can be prepared by mixing the above components in a conventional manner and then adding water or water and alcohol or the like to adjust the concentration to a predetermined level.

[0032] In the glass wool mat of this embodiment, the Igros (the content of the acrylic resin binder in a total of 100% by mass of the glass wool and the acrylic resin binder) is preferably more than 3.0% by mass and not more than 9.0% by mass, more preferably 4.0 to 8.0% by mass, and even more preferably 5.0 to 7.0% by mass, calculated as solids. When the Igros is within the above range, the glass wool mat can be lightweight and have appropriate rigidity. For example, when the glass wool mat is used as the core material of a vacuum insulation material, a vacuum insulation material lighter than conventional materials can be obtained. Furthermore, even if the glass wool mat (core material) is compressed due to a sudden drop in pressure during vacuum molding, the shape can be sufficiently maintained. Furthermore, the density of the glass wool mat (core material) and the thermal conductivity between fibers are less likely to increase, and outgassing is suppressed. This allows for a vacuum insulation material to be obtained that has excellent initial thermal conductivity and excellent long-term thermal performance, as degradation of insulation properties over time (increase in thermal conductivity over time) is suppressed. Normally, when Igros exceeds 3.0 mass%, adhesion of glass wool to manufacturing equipment and stickiness of the manufacturing equipment become significant, but according to the manufacturing method of this embodiment, even if Igros is within the above range, adhesion of glass wool to equipment and stickiness can be effectively suppressed. Igross can be measured by the following method. A 100mm x 100mm test piece (any thickness) is cut out from the glass wool mat, and its mass (Wa) is measured. The cut test piece is then placed in an electric furnace set at 550°C to decompose and remove the acrylic resin binder. The test piece is then removed from the electric furnace, and its mass (Wb) is measured after the acrylic resin binder has been decomposed and removed. The Igross (solid content equivalent) (mass%) is calculated using the following formula: Igross (mass%) = {(Wa-Wb) / Wa} x 100 Taking into account the numerical fluctuations in the measurement results, it is desirable to use the average value of the results of three or more measurements for one production lot for Igross.

[0033] The density of the glass wool mat of this embodiment may be appropriately set depending on the application. For example, the density of the glass wool mat as a roll / mat is 10 to 40 kg / m 3, 40 to 200 kg / m as board product 3 , 35 to 80 kg / m as the core material of vacuum insulation material 3 This can be considered. In particular, when glass wool mats are used as the core material of vacuum insulation materials, the density of the glass wool mats is 35 to 80 kg / m 3 is preferable, and more preferably 40 to 75 kg / m 3 and more preferably 45 to 70 kg / m 3 When the density of the glass wool mat is within the above range, the vacuum insulation material is lightweight, and the shape of the core material can be sufficiently maintained even if the core material is compressed due to a sudden drop in pressure during vacuum molding. Furthermore, there is a tendency to obtain a vacuum insulation material that has excellent initial thermal conductivity, and that has excellent long-term thermal performance because deterioration of thermal insulation properties over time (increase in thermal conductivity over time) is suppressed. The density of the glass wool mat can be measured in accordance with JIS A 9521.

[0034] [Vacuum insulation material] The glass wool mat of this embodiment can be particularly suitably used as a core material for vacuum insulation materials. A vacuum insulation material using the glass wool mat of this embodiment as a core material includes a core material and a film having gas barrier properties (hereinafter simply referred to as a "gas barrier film"), and may optionally include an adsorbent. The core material and the optional adsorbent are preferably sealed under reduced pressure within the gas barrier film. In the vacuum insulation material, the internal space of the gas barrier film is reduced in pressure by the action of the vacuum evacuation means and the adsorbent during production. The internal pressure of the vacuum insulation material may be, for example, 0.5 to 20 Pa, and preferably 0.5 to 10 Pa. When the internal pressure is within the above range, heat conduction via the gas inside the vacuum insulation material is suppressed, and the vacuum insulation material tends to have high thermal insulation properties.

[0035] [Core material] The core material is a component that provides the heat insulating performance of the vacuum insulation material and is made of the glass wool mat of this embodiment. The core material may be a single layer made of one glass wool mat of this embodiment, or a laminate made of 2 to 10 sheets of the glass wool mat. Glass wool mats are made by bonding the glass wool fibers together with an acrylic resin binder, which gives them moderate rigidity and makes them less likely to be crushed. They also act as a core material that is less likely to increase in density or thermal conductivity between fibers, thereby contributing to maintaining the insulating performance of vacuum insulation materials.

[0036] The density of the core material in the vacuum insulation material (density at the time of forming the vacuum insulation material) is 130 kg / m 3 More than 200kg / m 3 It is preferably less than 140 to 190 kg / m 3 and more preferably 150 to 180 kg / m 3 When the density of the core material is within the above range, the vacuum insulation material is lightweight, and the shape of the core material can be sufficiently maintained even when the gas barrier film compresses the core material due to a sudden drop in pressure during vacuum forming. Furthermore, a vacuum insulation material having excellent initial thermal conductivity and excellent long-term thermal performance can be obtained, with deterioration of heat insulating properties over time (increase in thermal conductivity over time) being suppressed. When the density of the core material is 130 kg / m when formed into a vacuum insulation material, 3 If the amount of glass wool is less than this, the surface smoothness becomes unstable because the amount of glass wool is too small, and the function as a heat insulating material decreases, making it difficult to use. The density of the core material can be calculated from the mass of the core material before vacuum forming and the dimensions (thickness, width, length) of the vacuum insulation material after vacuum forming.

[0037] From the viewpoints of improving heat insulation, reducing weight, and ease of handling, the thickness of the core material in the vacuum insulation material is preferably 3 to 40 mm, more preferably 4 to 30 mm, and even more preferably 4 to 20 mm per layer.

[0038] [Adsorbent] The adsorbent adsorbs (removes) outgassing (e.g., carbon monoxide, carbon dioxide, formaldehyde, amines, aromatic hydrocarbons, etc.) generated from the acrylic resin binder, gases (e.g., nitrogen, oxygen, carbon dioxide, etc.) that invade from the outside, and moisture (water vapor). By using the adsorbent to adsorb these gases and moisture, the vacuum insulation material tends to have better initial thermal conductivity and inhibits deterioration of its insulation properties over time (increase in thermal conductivity over time), resulting in better long-term thermal performance. The adsorbent may be of one type alone or a combination of multiple types.

[0039] Examples of adsorbents include adsorbents that mainly adsorb moisture (water vapor) by chemical adsorption, such as alkaline earth metal oxides such as calcium oxide and magnesium oxide, alkali metal oxides such as sodium oxide, and silica gel; adsorbents that mainly adsorb gases other than moisture (water vapor), such as crystalline aluminosilicates in which the cation that maintains the charge neutrality is copper, sodium, magnesium, silver, calcium, hydrogen, gold, or the like; and adsorbents that mainly adsorb gases other than moisture (water vapor), such as granulated inorganic binders (aluminum-based binders such as aluminum hydroxide and aluminum phosphate, magnesium phosphate, silicate-based binders, cement-based binders, inorganic sol-based binders, etc.) having amorphous voids. The adsorbent may contain additives such as a binder for molding and processing, and a water repellent for adjusting the moisture absorption rate, if necessary.

[0040] The form (shape) of the adsorbent is not particularly limited, and may be, for example, a powder, pellet, tablet, or the like, or a mixture of multiple types of adsorbents in the form of a powder, pellet, tablet, or the like. Furthermore, for example, one of the types of adsorbents may be partially or entirely coated around the other adsorbent, and then pelletized or tableted (for example, a pellet or tablet having a structure in which one adsorbent serves as a core and is surrounded by a layer of the other adsorbent).

[0041] <Gas barrier film> The film having gas barrier properties is not particularly limited as long as it has gas barrier properties, but is preferably a multilayer film in which a seal layer and a gas barrier layer are laminated in advance, and more preferably a multilayer film in which a seal layer, a gas barrier layer, and a protective layer are laminated in this order from the side in contact with the core material. The thickness of the gas barrier film is not particularly limited, but in order to prevent damage and a decrease in the degree of vacuum, it is preferable to use a film that is thicker than conventionally used films, for example, one with a thickness of 50 to 150 μm, more preferably 55 to 135 μm, and even more preferably 60 to 120 μm.

[0042] The gas barrier layer is a gas-impermeable layer that is provided to prevent a decrease in the degree of vacuum of the vacuum insulation material. Examples of the gas barrier layer include metal foil and a laminated film (deposited film) in which a metal or the like is vapor-deposited on a resin film. Examples of metals for the metal foil include aluminum, copper, stainless steel, and iron, with aluminum being preferred. Vapor-deposited films include those formed by vapor deposition, sputtering, or the like, using metals such as aluminum, stainless steel, cobalt, and nickel, or silica, alumina, or a combination thereof. Examples of resin films that can serve as the substrate for vapor-deposited films include films made from aromatic polyester-based resins such as polyethylene terephthalate (PET) resin and polybutylene terephthalate (PBT) resin; polyolefin-based resins such as polyethylene resin, polypropylene resin, and olefin copolymer; vinyl chloride-based resins such as polyvinyl chloride resin and vinyl chloride copolymer; polyamide resins such as nylon 6, nylon 66, and metaxylylenediamine-adipic acid condensate; styrene-based resins such as polyvinyl alcohol resin, acrylonitrile-butadiene-styrene copolymer, and acrylonitrile-styrene copolymer; thermoplastic resins such as acrylic resins such as polymethyl methacrylate resin, acrylic acid ester resin and methyl methacrylate ester copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol resin, and partially saponified versions thereof; and thermosetting resins such as phenolic resin and urea resin. The gas barrier layer is preferably a vapor-deposited film obtained by vapor-depositing aluminum onto an ethylene-vinyl alcohol copolymer resin, a vapor-deposited film obtained by vapor-depositing aluminum or silica onto a PET resin, or aluminum foil, or a laminate structure thereof. Metal foils and vapor-deposited films used for the gas barrier layer are well known and can be readily obtained on the market or prepared.

[0043] The thickness of the gas barrier layer is not particularly limited, but in the case of a vapor-deposited film, the thickness of the vapor-deposited film is preferably 200 to 2000 Å, and in the case of a metal foil, the thickness is preferably 5 to 10 μm.

[0044] The sealing layer is a layer that can be fused by heating, and is provided for the purpose of fusing the gas barrier films together to seal the core material and the adsorbent within the film. The sealing layer may be a heat-sealable resin film. Examples of the heat-sealable resin include polyolefin resins such as polyethylene resin and polypropylene resin, polyacrylonitrile resin, polyester resin, ethylene-vinyl alcohol copolymer, and mixtures thereof. Among these, polyethylene resin, polypropylene resin, and ethylene-vinyl alcohol copolymer are preferred. For polyethylene resin film, 0.90 to 0.98 g / cm 3 Preferably, the density is 0.01 to 0.01. For polypropylene resin film, 0.85 to 0.95 g / cm 3 Preferably, the density is 0.01 to 0.01.

[0045] The thickness of the sealing layer is not particularly limited, but is preferably 25 to 70 μm, as this can improve the sealing properties of the fused portion where the sealing layers are fused together and prevent leakage from the fused portion after vacuum packaging. The heat-sealable resins used for the sealing layer are well known and can be readily obtained on the market or prepared.

[0046] The protective layer is a layer that is optionally provided on the gas barrier layer for the purpose of protecting the gas barrier layer. Examples of protective layers include films made from aromatic polyester resins such as polyethylene terephthalate (PET) resin and polybutylene terephthalate (PBT) resin; polyolefin resins such as polyethylene resin, polypropylene resin, and olefin copolymer; vinyl chloride resins such as polyvinyl chloride resin and vinyl chloride copolymer; polyamide resins such as nylon 6, nylon 66, and metaxylylenediamine-adipic acid condensate; styrene resins such as polyvinyl alcohol resin, acrylonitrile-butadiene-styrene copolymer, and acrylonitrile-styrene copolymer; thermoplastic resins such as polymethyl methacrylate resin and acrylic resins such as acrylic ester resin and methyl methacrylate ester copolymer; and thermosetting resins such as phenolic resin and urea resin. Among these, films made from PET resin, nylon 6, or nylon 66 are preferred. The above resins may be used alone or in combination of two or more. The resins used in the protective layer are well known and are readily available on the market or can be prepared.

[0047] The protective layer may contain organic or inorganic fillers. In order to further improve the gas barrier performance of the gas barrier film, a gas barrier resin obtained by polymerizing or copolymerizing a vinyl monomer such as vinylidene chloride resin, acrylonitrile resin, or vinyl alcohol resin may be coated or laminated on the protective layer, or particles of such a resin may be mixed and dispersed in the resin film layer.

[0048] The thickness of the protective layer is not particularly limited, but is preferably 10 to 40 μm, as this can effectively prevent damage to the gas barrier film.

[0049] In the vacuum insulation material of this embodiment, as a measure against damage due to heat, impact, etc., the vacuum insulation material may be protected by attaching an insulating material such as glass wool or foam to the surface of the vacuum insulation material.

[0050] <Manufacturing method of vacuum insulation material> The vacuum insulation material of this embodiment can be produced by placing a core material and, optionally, an adsorbent inside a bag-shaped gas barrier film, evacuating the air inside the gas barrier film to reduce the pressure, and then sealing the gas barrier film. A bag-shaped gas barrier film can be produced, for example, by stacking two gas barrier films so that their sealing layers are in contact with each other, and heat-sealing the outer periphery to form a bag shape, leaving an opening for inserting a core material and an adsorbent. The method of reducing pressure and sealing can be a method conventionally known in the art, such as using a vacuum packaging machine.

[0051] The thermal conductivity of the resulting vacuum insulation material can be reduced by heating and drying the core material and the gas barrier film prior to vacuum sealing, preferably immediately before insertion into the vacuum sealing device. The drying temperature is, for example, 130 to 250°C for the core material and, for example, 50 to 90°C for the gas barrier film. When an adsorbent is provided, recesses or holes corresponding to the shape of the adsorbent may be provided in advance in the core material so that the position of the adsorbent does not shift when the container is sealed under reduced pressure.

[0052] The vacuum insulation material of this embodiment can be used in the same applications as conventional vacuum insulation materials, such as insulated boxes, refrigerated and frozen containers, refrigerators, freezers, rice cookers, hot water heaters, vending machines, storage batteries, automobiles, copiers, underfloor heating, housing equipment, storage tanks, refrigerated and frozen warehouses, and other general fields where insulation materials are used. [Example]

[0053] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.

[0054] The measurement and evaluation methods used in the examples and comparative examples are as follows.

[0055] [Igros] A 100 mm x 100 mm test piece (any thickness) was cut out from the glass wool mat, and its mass (Wa) was measured. The cut test piece was then placed in an electric furnace set at 550°C to decompose and remove the acrylic resin binder. The test piece was removed from the electric furnace, and its mass (Wb) was measured after the acrylic resin binder had been decomposed and removed. The igross (solid content equivalent) (mass%) was calculated using the following formula: Igross (mass%) = {(Wa-Wb) / Wa} x 100 The average value of the results of three or more measurements was used as the igloss value for each Example and Comparative Example.

[0056] [Moisture content of uncured glass wool mat] After adding moisture and before being compressed and heated, the moisture content (%) of the uncured glass wool mat was measured using a universal moisture meter HB-300 (manufactured by Kett Electric Laboratory Co., Ltd.). Specifically, the moisture content was measured by inserting the sensor head of the moisture meter into the uncured glass wool mat just before it entered the oven as it was transported on the conveyor (see the "moisture content measurement" position in Figure 1(A) - approximately halfway between the press roll and the oven entrance) at a position about 300 mm from the side edge to a depth of about 100 mm from the surface (top surface). Measurements were taken at 10 locations, and the average value was taken as the moisture content of the uncured glass wool mat. For comparison, the moisture content (%) of the uncured glass wool mat before adding moisture was also measured in the same manner.

[0057] [Production stability of glass wool mats] In the examples and comparative examples, adhesion of glass wool to the manufacturing equipment (press rolls, compression / heating conveyors, etc.) and stickiness of the manufacturing equipment were observed, and the manufacturing stability of the glass wool mat was evaluated according to the following evaluation criteria. (Evaluation criteria) A (Excellent): Glass wool adhesion to manufacturing equipment and stickiness of manufacturing equipment are suppressed, allowing stable production of glass wool mats for more than one hour. B (Good): The adhesion of glass wool to the manufacturing equipment and the stickiness of the manufacturing equipment gradually increased, but glass wool mats could be stably manufactured for more than 30 minutes but less than 1 hour. C (Acceptable): Glass wool adheres to the manufacturing equipment and the manufacturing equipment is sticky, but glass wool mats can be manufactured stably for up to 30 minutes. D (poor): Immediately after the start of production, adhesion of glass wool to the production equipment and stickiness of the production equipment were noticeable, making it impossible to stably produce glass wool mats.

[0058] [Example 1] Glass wool (average fiber diameter 4.5 μm, basis weight 1270 g / m) was produced using a fiberizer that uses the melting centrifugal method. 2 An acrylic resin binder (concentration 18% by mass, flow rate 480-540 L per 1000 kg of glass discharged) was sprayed onto the glass wool discharged from the fiberizer, and the resulting mixture was collected on a flight conveyor and formed into a mat, to obtain an uncured glass wool mat. While the obtained uncured glass wool mat was being transported on a transport conveyor, water was sprayed onto the top surface of the uncured glass wool mat using a water sprayer as shown in Figure 1(A). As shown in Figure 2, six water sprayers (Ikeuchi Co., Ltd. "Small-volume hollow cone nozzle 1 / 4M K 050N S303W") were arranged in a row at equal intervals across the width of the uncured glass wool mat (width 1100 mm). The amount of water applied (spray amount) was 0.038 to 0.053 L / m per unit area of ​​the uncured glass wool mat. 2 The average particle size of the sprayed water was 220 μm. Next, the obtained uncured glass wool mat with moisture was pressed using a pair of upper and lower press rolls as shown in Figure 1(A) to a thickness of 7 mm, and then sandwiched between upper and lower compression and heating conveyors in a hot air passage oven at a heating temperature of 260°C until the density of the glass wool mat reached approximately 160 kg / m during its stay in the oven. 3 The glass wool mat after compression and heating was cut with a trim saw to adjust the width, and cut with a chopper to adjust the length, and the glass wool mat (thickness 22 mm, density 55 kg / m) was obtained.3 , Igross: 6.0% by mass was obtained. The measurement and evaluation results are shown in Table 1. In Example 1, the glass wool mat could be stably produced for more than one hour without being affected by stickiness on the production equipment.

[0059] [Example 2] Glass wool weight: 1590g / m 2 A glass wool mat to be used as the core material of a vacuum heat insulating material was obtained in the same manner as in Example 1, except that the above-mentioned conditions were met. The measurement and evaluation results are shown in Table 1. As in Example 1, the glass wool mat was able to be produced stably for about an hour. The moisture content of the uncured glass wool mat with moisture was higher than in Example 1, and insufficient baking (insufficient curing of the binder) was confirmed in some areas, but this was at a level that would not cause any practical problems.

[0060] [Example 3] A glass wool mat was obtained in the same manner as in Example 1, except that the method of adding moisture to the uncured glass wool mat was changed to the method shown in FIG. 1(B). More specifically, six water sprayers were arranged in a row at equal intervals in the width direction of the uncured glass wool mat, as in Example 1, and were positioned so that water from the water sprayers was sprayed directly onto the front surface of the upper press roll. By arranging the water sprayers in this manner, water was indirectly applied from the upper press roll to the top surface of the uncured glass wool mat as the uncured glass wool mat passed through the press roll. The measurement and evaluation results are shown in Table 1. Glass wool gradually accumulated on the surface of the upper press roll, and there was concern that the accumulated glass wool would adhere to the surface and scrape off the top surface of the uncured glass wool mat on the conveyor (the glass wool clumps would tear off), so production was halted after more than 30 minutes.

[0061] [Example 4] As shown in Figure 1(C), a glass wool mat was obtained in the same manner as in Example 2, except that a scraper (having the same width as the press roll) for peeling off the glass wool adhering to the upper press roll was installed on the back side of the upper press roll. The measurement and evaluation results are shown in Table 1. The glass wool peeled off from the surface of the upper press roll by the scraper gradually accumulated between the upper press roll and the scraper, and as the accumulated glass wool came into contact with the uncured glass wool mat on the conveyor, the uncured glass wool mat on the conveyor was lifted up as the press roll rotated, so production was stopped after 30 minutes.

[0062] [Example 5] A glass wool mat was obtained in the same manner as in Example 1, except that the method of adding moisture to the uncured glass wool mat was changed to the method shown in FIG. 1(D). More specifically, six water sprayers were arranged in a row at equal intervals in the width direction of the uncured glass wool mat, as in Example 1, and were positioned so that water from the water sprayers was sprayed directly onto the back surface of the upper press roll, and the water flowed on the surface of the upper press roll in a direction opposite to the rotation direction of the roll. By arranging the water sprayers in this manner, water was indirectly applied from the upper press roll to the top surface of the uncured glass wool mat as it passed through the press roll. The measurement and evaluation results are shown in Table 1. Although adhesion and stickiness of the glass wool to the oven (compression / heating conveyor, etc.) was suppressed, the amount (force) of water sprayed was not enough to remove the glass wool that had adhered to the surface of the upper press roll, making continuous production more difficult than in Example 2, and production was discontinued after 30 minutes.

[0063] [Comparative Example 1] A glass wool mat was obtained in the same manner as in Example 1, except that no moisture was added to the uncured glass wool mat. The measurement and evaluation results are shown in Table 1. Immediately after production began, glass wool began to adhere to the press rolls and oven (compression / heating conveyors, etc.) and the equipment became noticeably sticky, the top surface of the glass wool mat was scraped off (clumps of glass wool were torn off), and stable production of glass wool mat was not possible.

[0064] From the above, the method of spraying water directly onto the top surface of the uncured glass wool mat is particularly effective for stabilizing production, since continuous production for over one hour was possible in Examples 1 and 2. Furthermore, in Example 2, although the level was not problematic in practice, insufficient baking of the glass wool mat was confirmed, so the moisture content of the uncured glass wool mat is more preferably 25 to 40%, and even more preferably 30 to 35%. The moisture content of the uncured glass wool mat was measured only in Examples 1 and 2 (examples in which moisture was directly applied) and Comparative Example 1 in order to verify the preferred range of moisture content.

[0065] [Table 1] [Industrial Applicability]

[0066] According to the method for manufacturing glass wool mat of the present invention, even if the igloss is high, adhesion of glass wool to the manufacturing equipment and stickiness of the manufacturing equipment can be suppressed, and glass wool mat can be manufactured stably, making it suitable as a method for manufacturing glass wool mat to be used as the core material of vacuum insulation materials, etc.

Claims

1. a binder application step of applying an acrylic resin binder to the glass wool to obtain uncured binder-coated glass wool; A fiber collecting step of collecting the uncured binder-attached glass wool on a flight conveyor to form a mat, thereby obtaining an uncured glass wool mat; A moisture-adding step of adding moisture to the uncured glass wool mat to obtain a moisture-added uncured glass wool mat; a compression heating step of compressing and heating the moisture-containing uncured glass wool mat in an oven to obtain a glass wool mat; A method for producing a glass wool mat, comprising:

2. The method for manufacturing a glass wool mat according to claim 1, wherein in the moisture imparting step, moisture is directly imparted to the uncured glass wool mat.

3. The method for manufacturing a glass wool mat according to claim 1 or 2, wherein in the moisture imparting step, moisture is indirectly imparted to the uncured glass wool mat.

4. The method for manufacturing a glass wool mat according to claim 1 or 2, wherein the glass wool mat has an iglos content of 4.0 to 8.0 mass% in terms of solid content.

5. In the moisture application step, the amount of moisture applied per unit area to the uncured glass wool mat is 0.008 to 0.070 L / m ２ The method for producing a glass wool mat according to claim 1 or 2,

6. The method for manufacturing a glass wool mat according to claim 1 or 2, further comprising a pressurizing step of pressing the moisture-added uncured glass wool mat with a press roll simultaneously with or after the moisture-adding step and before the compression and heating step.

7. The method for manufacturing a glass wool mat according to claim 1 or 2, wherein the glass wool mat is used as a core material of a vacuum insulation material.

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