JP3907277B2 - Method for manufacturing hygroscopic article - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an article having moisture absorption / release properties used for various applications including building and storage container materials and interior materials.
[0002]
[Prior art]
Conventionally, in order to further reduce the range of humidity change inside buildings, storage containers, etc. with respect to changes in temperature and humidity in the external environment, the interior material has been made of a material that absorbs and releases moisture. For example, buildings and storage containers are constructed using materials that have hygroscopic properties such as traditional wall soil and wood (especially paulownia), or the hygroscopic properties of metals, resins, etc. are insufficient. A moisture absorbing / releasing agent such as silica gel or activated clay (montmorillonite) was placed or mounted inside a building or storage container made of various materials.
[0003]
[Problems to be solved by the invention]
In the former method described in the prior art, if it is a wall soil, the plasterer must be coated with a scissors etc., and if it is wood, it is cut, cut and polished with a saw, scissors etc. Since it is necessary to join with an adhesive or the like, there is a problem that the efficiency of the manufacturing process is poor, and further, the suitability for forming process such as bending and drawing is poor. Also, physical properties such as water resistance and abrasion resistance are insufficient depending on the application. In such a case, these materials have a small range of flexibility in changing the physical properties, and the physical properties can be improved by selecting the materials themselves. Was difficult.
[0004]
Further, in the latter method, for example, placing a bag containing silica gel or the like requires a space for it, so that in the case of a container, the effective space is reduced correspondingly, and in the case of a building, it is an obstacle. There was a problem of becoming (obstructing walking if placed on the floor).
[0005]
Therefore, it has been attempted to add and disperse the moisture absorbing / releasing agent to a resin which has excellent molding processability and has a wide variety of physical properties and a high degree of freedom in a selection range but does not absorb moisture. However, since the moisture absorbing / releasing agent is coated and sealed with the resin, the moisture absorbing / releasing effect is greatly reduced. If a very large amount of moisture absorbing / releasing agent is added, part of the moisture absorbing / releasing agent is exposed on the resin surface, so the moisture absorbing / releasing effect is slightly improved, but instead the resin becomes brittle and breaks during molding. There are problems such as insufficient strength and reduced surface physical properties such as wear resistance, which are not practical.
[0006]
The present invention has been made in view of the problems as described above, and the object of the present invention is to provide a moisture-absorbing / releasing article having excellent flexibility in molding processing and having a wide variety of physical properties and a high degree of freedom in a selection range. It is to provide a manufacturing method.
[0007]
[Means for Solving the Problems]
In a first production method according to the present invention, a liquid composition in which a volatile substance adsorbed in moisture absorbent / release agent particles is dispersed in a liquid resin is obtained in a state where the volatile substance is not released. It is characterized in that the liquid composition is solidified in a state where it is molded into a predetermined article shape, and then the volatile substance in the moisture absorbent / release agent particles is volatilized and released. The moisture-absorbing / releasing article obtained by this method is the first type as shown in FIG. 1, that is, the moisture-absorbing / releasing agent particles P are added and dispersed in the resin R having a large number of cavities a opened on the surface. It becomes the structure which becomes.
[0008]
Further, as the moisture absorbing / releasing article to be finally formed, the second type as shown in FIG. 2, that is, a resin having a large number of cavities a opened in the surface on the surface of the base B made of an arbitrary material. A form in which a moisture absorbing / releasing resin layer L formed by adding and dispersing moisture absorbing / releasing particles P in R is laminated may be used.
[0009]
The method of manufacturing the second type of article as shown in FIG. 2 is the second manufacturing method according to the present invention, and this method is a method in which a volatile substance is adsorbed in a moisture absorbent / release agent particle. The liquid composition dispersed in the liquid resin is applied to the surface of the substrate in a state in which the volatile substances are not released, and then the volatile substances in the moisture absorbent particles are volatilized and released. The liquid composition is solidified. Alternatively, a liquid composition prepared by dispersing a volatile substance adsorbed in moisture absorbent / release agent particles in a liquid resin is coated on a support sheet in a state where the volatile substance is not released, Next, after the liquid composition is solidified in a state where the volatile substances in the moisture absorbent / release agent particles are volatilized and released, the liquid composition is peeled off from the support sheet to form a sheet-like moisture absorbent / release resin layer. The hygroscopic resin layer is bonded to the substrate surface with an adhesive.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, a resin that does not absorb moisture (or is poor) by itself, but has excellent molding processability, and has a wide variety of physical properties and a large degree of freedom in selection range, is used depending on the application. This resin is appropriately selected from the following (1) to (3).
(1) Polymethyl (meth) acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate / butyl (meth) acrylate copolymer, methyl (meth) acrylate / ethyl (meth) acrylate copolymer Acrylic resin such as (meth) acrylic acid alkyl ester alone or as a copolymer (however, (meth) acrylate means acrylate or methacrylate), polyethylene terephthalate, polybutylene terephthalate, ethylene / terephthalate / isophthalate Thermoplastic polyesters such as polymers, polyolefins such as polyethylene, polypropylene and olefinic thermoplastic elastomers, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, ethylene tetrafluoride Fluorine resins such as polyalkylene copolymer, polyvinyl chloride, a butyral resin, polystyrene, ABS (acrylonitrile butadiene styrene copolymer), a thermoplastic resin such as polycarbonate.
(2) Thermosetting resins such as unsaturated polyester resins, epoxy resins, phenol resins, melamine resins, urea resins, and two-component curable polyurethane resins.
(3) Monomers such as trimethylolpropane tri (meth) acrylate and dipentaerythritol hexa (meth) acrylate, prepolymers or polymers such as urethane (meth) acrylate, epoxy (meth) acrylate, and triazine (meth) acrylate A monomer having a polymerizable functional group such as a (meth) acryloyl group or an epoxy group in the molecule, or a prepolymer or polymer.
[0011]
The cavity opened to the surface is a cavity communicating from the inside of the resin article to the surface of the resin article. It is preferable that such a plurality of cavities communicate with each other and the communicating cavities are distributed to the inside of the resin article because the moisture absorption and desorption effect is good. A cavity may communicate from the front surface to the back surface of the article. The article of the present invention has a large number of such cavities, and has a uniform or substantially uniform distribution over the whole article at least near the surface of the article. Of course, a cavity that does not open on the surface may exist in parallel with the cavity that opens on the surface.
[0012]
The diameter of the hollow body is usually in the range of about 10 to 1000 μm. The hollow body may be directly opened on the surface of the article or may be connected to the article surface by a passage. The diameter of the passage is in the same range as the diameter of the cavity body. The shape of the hollow body may be a sphere, a spheroid, a polyhedron, or other various shapes. The wall surfaces of the hollow body and the passage are made of resin constituting the resin article.
[0013]
As the moisture-absorbing / releasing agent particles, a particle that does not dissolve in water and does not change even when exposed to air for a long period of time is selected. For example, particles of moisture-absorbing and releasing minerals such as activated clay (montmorillonite), ettringite, tobermorite, shells such as scallops, and the particle size is about 0.1 to 100 μm. Alternatively, it may be a saponified product of a graft copolymer of starch and acrylonitrile, a crosslinked polyvinyl alcohol, a salt of a reaction product of polyvinyl alcohol and maleic anhydride, particles of moisture-absorbing / releasing organic substances such as rice husks and wood. The amount of the moisture absorbing / releasing agent particles added to the resin is about 10 to 50% by weight.
[0014]
The first type of article can take various shapes such as a sheet, a flat plate, a curved and deformed curved plate, a columnar body such as a polygonal column or a cylinder, and the like. What is necessary is just to make it an appropriate shape according to a use. In addition, its uses include interior materials for buildings such as walls, floors, and ceilings, interior materials for vehicles such as automobiles, trains, ships, and aircraft, doors, window frames, handrails and other furniture, furniture such as fences, Examples include partitions, containers, and others.
[0015]
In the second type of article, a hygroscopic resin layer is laminated on the surface of a base made of an arbitrary material. Materials for the substrate include wood such as wood veneer, wood plywood, particle board, wood fiber board (MDF, etc.), metal such as iron, copper, aluminum, polyvinyl chloride, acrylic resin, polyolefin resin, polyester resin, ABS Examples thereof include resins such as resins and phenol resins, ceramics such as glass and ceramics, non-ceramic ceramic materials such as gypsum, calcium silicate, and cement, paper, fabric, and non-woven fabric. The shape can take various shapes like the above-mentioned article. Moreover, the thing similar to what was mentioned above is mentioned as a use.
[0016]
As volatile substances, in addition to water, alcohols such as ethyl alcohol and methyl alcohol, paraffinic hydrocarbons such as hexane and pentane, aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, acetone , Ketones such as methyl ethyl ketone, or dimethylformamide.
[0017]
As the resin of the liquid composition, a liquid resin is used without using a volatile diluent or dispersant. The degree of “liquid” means that bubbles are generated in the resin by the gas generated by volatilization from the moisture-absorbing / releasing agent particles, and the resin is softened to such an extent that at least a part of the bubbles can open on the resin surface. Just do it. For example, there are the following (1) to (3).
(1) A molten thermoplastic resin. In the case of this resin, the volatile substance adsorbed by the moisture absorbing / releasing agent is released by the heat at the time of melting by heating.
(2) Uncured liquid material of thermosetting resin. In the case of this resin, the volatile substance adsorbed by the moisture absorbing / releasing agent is released by heat at the time of curing.
(3) An uncured liquid material of an ionizing radiation curable resin that is cured by ionizing radiation such as ultraviolet rays and electron beams. In the case of this resin, the volatile substance adsorbed by the moisture absorbing / releasing agent is released by heating or the like.
[0018]
In order to manufacture the first type article, for example, the following methods (1) and (2) are used.
(1) A liquid composition is coated on a releasable support sheet (process paper, etc.) to form a sheet (film), and a volatile substance is volatilized from moisture absorbing / releasing agent particles to surface the composition. After the liquid composition is solidified in a state of being made porous by generating bubbles having a large number of cavities that open in the substrate, it is peeled (released) from the support sheet.
(2) By injecting the liquid composition into both male and female molds of a predetermined shape, volatilizing the volatile substance from the moisture-absorbing / releasing agent particles, and generating bubbles having a large number of cavities opened on the surface of the composition After solidifying in a porous state, the mold is released from the mold.
[0019]
To manufacture the second type of article, a liquid composition is applied to the surface of a substrate made of an arbitrary material, and a volatile substance is volatilized from the moisture-absorbing / releasing agent particles to open the composition on the surface. By forming bubbles having a large number of cavities, it is solidified in a porous state, or the moisture absorbing / releasing resin layer formed by the method of (1) above is bonded to the substrate using an adhesive. .
[0020]
In order to help create a porous structure having a large number of cavities open on the surface, or to increase cushioning by increasing the thickness of the article, a known foaming agent is contained in the liquid composition. It is also a preferred embodiment that the foaming agent is foamed at the same timing as or before and after the release of the volatile substance from the moisture-absorbing / releasing agent particles. As the foaming agent, those that release gas by thermal decomposition are preferable. Specifically, an organic foaming agent such as azodicarbonamide, azobisisobutyronitrile, 4-4′-oxybisbenzenesulfonyl hydrazide, or an inorganic foaming agent such as sodium hydrogen carbonate is used. The amount of the foaming agent added is about 1 to 5 parts by weight with respect to 100 parts by weight of the resin.
[0021]
If necessary, a decorative layer or a concavo-convex pattern may be provided on the surface of the article (or the back side if the article is transparent) as long as the moisture absorption / release property is not inhibited. Examples of the decorative layer include a pattern printing layer provided by a known ink and printing method, a metal thin film layer such as aluminum, and the like, and these are preferably provided partially rather than the entire surface. In addition, a decorative effect can be obtained by adding a known dye or pigment to the inside of the article within a range that does not impair moisture absorption and desorption. As the concavo-convex pattern, it is a concavo-convex pattern such as a hairline, pear texture, sand texture, crest, wood grain conduit groove, tile or brick joint, etc., using a known embossing method or having a concavo-convex pattern on the surface A method is used in which the liquid composition is applied to the surface of the sheet, made porous and solidified, and then the solid composition is peeled off to transfer the uneven pattern on the surface of the support sheet. At this time, care must be taken not to destroy a porous structure having a large number of cavities that are open to the surface. From this point, the latter method is preferable.
[0022]
【Example】
(Example)
Activated clay (“V2R” manufactured by Mizusawa Chemical Co., Ltd., particle size 50 μm) is used as the moisture absorbing / releasing agent particle, and 30 parts by weight of the activated clay is dispersed in 50 parts by weight of ethyl acetate and stirred to be volatile to the activated clay particles. Ethyl acetate was adsorbed as a material. At this time, the weight increase by ethyl acetate of the activated clay was 20 parts by weight. After this activated clay was dispersed in a polyvinyl chloride sol having the following composition (unit: parts by weight) and coated on a flame retardant paper (“WK-ADS” manufactured by Kojin Co., Ltd.) of 70 g / m ² to a thickness of 150 μm. The polyvinyl chloride sol coat layer was solidified by heating at 190 ° C. for 1 minute, and the volatile substances in the moisture absorbent / release agent particles were volatilized and released. Thereafter, heating was performed at 210 ° C. for about 1 minute to complete the foaming of the polyvinyl chloride sol layer, thereby obtaining a humidity control wall material sheet having many cavities opened on the surface. The diameter of the cavity of the obtained sheet was 50 to 450 μm.
[0023]
<Composition of polyvinyl chloride sol>
Polyvinyl chloride paste resin (manufactured by Kaneka "PSL-280") 100
Plasticizer: DOP 60
Titanium dioxide (rutile type) powder 15
Calcium carbonate powder 50
Foaming agent: azodicarbonamide (“AZ-L30” manufactured by Otsuka Chemical) 3
Stabilizer ("KF-838" manufactured by Kyodo Yakuhin) 1
[0024]
(Comparative example)
30 parts by weight of the same untreated activated clay as in the examples was added to a polyvinyl chloride sol having the same composition as described above, and a thickness of 150 μm on 70 g / m ² flame retardant paper (“WK-ADS” manufactured by Kojin). I coated it. Thereafter, the polyvinyl chloride sol coat layer was solidified by heating at 190 ° C. for 1 minute, and the foaming of the polyvinyl chloride sol layer was completed by heating at 210 ° C. for about 1 minute to obtain a wall material sheet.
[0025]
The humidity control performance of each wall material sheet obtained in Examples and Comparative Examples was compared. Specifically, a cube-shaped aluminum case having an inner size of 25 × 25 × 25 cm is prepared, and a wall material sheet cut into a size of 25 × 25 cm is bonded to the inner wall surface of the aluminum case. ℃, 50% RH), the aluminum case is sealed, and the outside air temperature is changed in a cycle of 20 ° C for 0.5 hours, 30 ° C for 2 hours, 20 ° C for 2 hours, and 10 ° C for 2 hours. The humidity change in the aluminum case was measured. The obtained results are shown in FIG. As can be seen from the graph of FIG. 3, when the wall material sheet of the comparative example was used, the humidity fluctuated in the range of + 40% and −20% with respect to the initial set humidity of 50%. The degree of using was able to keep humidity within a range of about ± 10% with respect to temperature change, and an excellent humidity control effect was recognized.
[0026]
【The invention's effect】
As described above, according to the present invention, sufficient moisture absorption / release properties can be imparted to an article without adding an extremely large amount of moisture absorption / release agent. In addition, the properties inherent to the resin, such as molding processability, water resistance, wear resistance, and the like, as well as the wideness of the variable / selectable range thereof are not impaired. Further, when the manufactured article is used, a bag or the like containing a moisture absorbent / release agent is not placed or attached, so that it does not take up space and is not in the way.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of the structure of a first type article manufactured by the method of the present invention.
FIG. 2 is a cross-sectional view showing a structural example of a second type of article manufactured by the method of the present invention.
FIG. 3 is a graph comparing humidity control performance in Examples.
[Explanation of symbols]
a Cavity R Resin P Hygroscopic particle B Substrate L Hygroscopic resin layer

Claims (3)

A method for producing a moisture-absorbing / releasing material obtained by adding and dispersing moisture-absorbing / releasing particles in a resin having a large number of cavities that are open on the surface, and adsorbing volatile substances in the moisture-releasing / releasing agent particles. A liquid composition made by dispersing the product in a liquid resin is molded into the shape of a predetermined article without volatile substances released, and then the volatile substances in the moisture absorbent particles are volatilized and released. A method for producing a hygroscopic article, characterized in that a liquid composition is solidified in a caulked state. A moisture-absorbing / releasing article formed by laminating a moisture-absorbing / releasing resin layer formed by adding and dispersing moisture-absorbing / releasing particles in a resin having a large number of cavities open to the surface on the surface of a base made of an arbitrary material. A method of manufacturing a liquid composition in which a volatile substance adsorbed in moisture absorbent / release agent particles is dispersed in a liquid resin, and the volatile substance is not released on the surface of the substrate. A method for producing a moisture-absorbing / releasing article, characterized in that the liquid composition is solidified in a state in which the volatile substance in the moisture-absorbing / releasing agent particles is volatilized and released. A moisture-absorbing / releasing article formed by laminating a moisture-absorbing / releasing resin layer formed by adding and dispersing moisture-absorbing / releasing particles in a resin having a large number of cavities open to the surface on the surface of a base made of an arbitrary material. A method for producing a liquid composition in which a volatile substance adsorbed in moisture absorbent / release agent particles is dispersed in a liquid resin, and the volatile substance is not released on the support sheet. Next, after the liquid composition is solidified in a state where the volatile substances in the moisture-absorbing / releasing agent particles are volatilized and released, the sheet-like moisture absorbing / releasing resin layer is peeled off from the support sheet. A method for producing a moisture absorbing / releasing article, comprising forming a film and bonding the moisture absorbing / releasing resin layer to the surface of a substrate with an adhesive.

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