JPH0428840B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a moisture-permeable anti-condensation wallpaper and a method for producing the same. [Prior Art] Wallpaper is generally a wallpaper made of paper, fiber, etc. that is applied as a finishing material to walls and ceilings of buildings.
It is a common name for a sheet-like plastic material made of materials such as plastic or metal foil. Recent architecture has become so-called Western-style, with panels, prefabricated, reinforced concrete, etc.
Furthermore, with the development of metal sashes, windows have become more airtight, but as a result of the complete lack of ventilation indoors, the problem of condensation on walls has arisen.
In other words, the problem of condensation on the walls of a closed room is not only the above-mentioned problem of the airtightness of the window sash, but also the increase in the amount of water used in daily life due to improved living standards, and the problem of water vapor caused by the use of heating appliances such as kerosene stoves and gas stoves. This is thought to be one of the causes. By the way, as a way to prevent this type of condensation, it is thought that this problem can be solved by inserting heat insulating material inside the wall to prevent the indoor wall surface temperature from dropping below the dew point temperature, but in order to do so, It is important to maintain the performance of the heat insulating material and wood inside the wall and to prevent stuffiness due to humidity inside the wall, and for this reason, wall materials that are particularly moisture permeable and air permeable have recently been attracting attention. Other performance requirements for wall materials include, of course, resistance to staining from condensed water, but even if condensed water gets on it, it is important that it can be easily wiped off. Although paper-based wallpaper and textile-based wallpaper have moisture absorbing and desorbing properties, they are easily stained, and their microporous surfaces tend to generate mold, and it is also difficult to wipe away adhered dirt. Therefore, these materials do not fully satisfy the characteristics required for the above-mentioned wallpaper. In order to improve these conventional paper-based or textile-based wallpapers, we have developed a wipeable wallpaper in which the surface of the wallpaper is coated with a microporous film that has a large number of micropores that allow water vapor to pass through but not liquid water. Easy wallpapers have been developed. This type of microporous film is manufactured by a wet method in which the solvent is replaced with water after spreading a solution, or a dry method in which micropores are created physically or mechanically, and it is attached to the surface of the wall material with an adhesive or the like. Ru. In addition, wallpaper made of vinyl chloride resin is hard to stain and is easy to wipe, but it is not moisture permeable and is prone to condensation. Wallpaper is manufactured by adding a polymeric moisture absorbent made of a super absorbent resin to this vinyl chloride resin, and by dispersing and embedding the polymer absorbent fine powder in the vinyl chloride resin layer of the wallpaper, the wallpaper is created. Attempts have also been made to prevent surface condensation. [Problems to be Solved by the Invention] Among the conventional improved wallpapers mentioned above, paper-based or textile-based wallpapers whose surfaces are coated with microporous films are susceptible to the formation of fine pores in the surface film that are susceptible to dust, dust, and other contaminants. , it is easy to get clogged and it is difficult to wipe away dirt, so the moisture absorption and release performance gradually decreases. Furthermore, the manufacturing process of the microporous film, both dry and wet, is complicated and requires special equipment, and it is also necessary to laminate and adhere it to decorative paper using an adhesive.
There is also the problem that the manufacturing cost of wallpaper increases. In wallpaper made of vinyl chloride resin film with a dispersed embedded polymeric moisture absorbent, the moisture absorbent exposed on the surface of the wallpaper absorbs moisture well, but the moisture absorbent buried inside the resin layer is covered with vinyl chloride resin, which has no hygroscopicity. As a result, the moisture absorbing ability is significantly inhibited, and for the same reason, moisture once absorbed is difficult to dissipate, resulting in an insufficient moisture absorbing and desorbing ability as a whole. In addition, if a polymer moisture absorbent with a high water absorption capacity is used to increase its moisture absorption capacity, the moisture absorbent exposed on the wallpaper surface becomes sticky when absorbing water, making the wallpaper surface sticky and staining when wiped with water. It has the disadvantage of impairing moisture absorption performance. Therefore, the present invention provides a moisture-permeable dew condensation-preventing wallpaper that has extremely good heat insulation properties, is extremely effective in preventing dew condensation, has excellent stain resistance, and has a good texture without using a microporous film. With the goal. A further object of the present invention is to provide a method for manufacturing the moisture-permeable anti-condensation wallpaper, which is a simple process and does not require special machinery. [Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have conducted intensive research, and as a result, a lower layer of a moisture-permeable resin foam made of closed cells of a moisture-permeable resin such as polyurethane is applied to the wallpaper surface. By dispersing and embedding a moisture absorbent with a water absorption capacity of 200 times or more in the moisture-permeable resin, the insulation properties are improved, and the formation of dew condensation on the wallpaper surface can be delayed or prevented as much as possible, and the moisture in the atmosphere can be further reduced. Even if the foam layer is made up of closed cells, moisture permeates and diffuses through the relatively thin upper layer of moisture-permeable resin at the molecular level, reaching the moisture absorbent inside the lower layer in a short time and absorbing and storing it. In addition, when the atmosphere is dry, the upper and lower layers are made of a moisture-permeable resin, so we have found that the air is diffused through the moisture-permeable resin. Therefore, it has been found that it is possible to obtain a dew condensation-preventing wallpaper that has excellent heat insulation properties, moisture absorption and desorption properties, a smooth surface, and excellent stain resistance. Therefore, from this point of view, it is preferable to use a water-absorbing agent with a higher water-absorbing capacity, since the better the dew condensation prevention performance of the wallpaper will be, but on the other hand, if the water-absorbing capacity exceeds 200 times,
It was also discovered that when moisture is absorbed, the surface becomes sticky, and therefore, the present invention provides a lower layer that ensures high moisture absorption and desorption performance as a coating layer on the surface of wallpaper, and a layer that compensates for the above-mentioned disadvantages of the lower layer and also has a layer that prevents dew condensation and is antifouling. We adopted a laminated structure with an upper layer that also has properties. In other words, on the surface of the wallpaper mount, a polymer moisture absorbent with a water absorption capacity of 200 times or more is layered with a lower layer of moisture permeable resin foam consisting of dispersed and embedded closed cells, and a moisture permeable resin as the main component. It is characterized by laminating and fixing an upper layer covering a lower layer of foam. The above-mentioned moisture permeable resin foam consisting of closed cells can be made into closed cells under well-known conditions such as foaming by mechanical stirring, foaming with gas generated during a chemical reaction, liquefied gas, etc. It can be formed by a method of press-fitting, a method of mixing or impregnating a volatile solvent with a low boiling point and vaporizing it, a method of using a blowing agent such as a thermal decomposition type, etc., and is not particularly limited. For example, in the case of a decomposable blowing agent, azodicarbonamide can be used and heated to a predetermined temperature to form closed cells. However, it is most preferable to use thermally expandable microcapsules made of a thermoplastic resin containing a vaporizable liquid, so that the closed cells are formed of the thermoplastic resin membrane of the thermally expanded microcapsules. This is because when thermally expandable microcapsules are used, production is extremely easy, the closed cells become uniform, and the resulting foam can exhibit a better texture than ever before. Note that in the present invention, closed cells need only be substantially closed cells, that is, closed cells that are completely independent or have a high closed cell ratio by eliminating communication between the cells as much as possible. In short, we use closed cells to improve insulation as much as possible,
At the same time, there is no problem as long as the moisture absorbent contained in the resin layer is a closed cell that can sufficiently exhibit moisture absorption and release functions with respect to the outside world through the moisture permeable resin layer. In the case where the above-mentioned microcapsules are used to form closed cells in the moisture-permeable resin layer, the most preferable manufacturing method for obtaining moisture-permeable anti-condensation wallpaper is the following method. That is, this invention uniformly mixes thermally expandable microcapsules formed by embedding a vaporizable liquid in a thermoplastic resin, a moisture-permeable resin, and a super water-absorbing resin with a water absorption capacity of 200 times or more as a moisture absorbent. Then, a manufacturing method was adopted in which the obtained compound was undercoated on the surface of a wallpaper mount, and then a topcoat containing the moisture permeable resin as the main component was applied, followed by heating and foaming. By overcoating the moisture-permeable resin as a moisture-permeable resin layer or a moisture-permeable resin foam layer consisting of closed cells, water with a high water absorption capacity of 200 times or more is embedded in the lower layer of resin through the upper layer of the moisture-permeable resin of the top coat. Moisture in the atmosphere is absorbed by the molecular moisture absorbent, and conversely it is released into the atmosphere, so it has an overcoat layer that has excellent moisture absorption and desorption properties and does not become sticky when absorbed, so even if the lower layer has a water absorption capacity of more than 200 times. It is possible to obtain wallpaper without stickiness on the surface even by using a moisture absorbent having the following properties. In addition, if a compound obtained by mixing the moisture permeable resin with an organic or inorganic moisture absorbent such as a polymer moisture absorbent that does not become sticky when water is absorbed and has a water absorption capacity of 2 to 200 times is used as the upper layer resin,
Moisture absorption and desorption performance and dew condensation prevention performance are improved. Furthermore, in order to further enhance the texture, it is preferable to use a mixture of the moisture-permeable resin, the microcapsules, and a moisture absorbent having a water absorption capacity of 2 to 200 times, since the resulting wallpaper will have a good texture and excellent moisture absorption and desorption properties. The gist of the present invention is a moisture-permeable anti-condensation wallpaper having the above characteristics. The moisture-permeable resin used in the present invention is not particularly limited as long as it is soluble in solvents, does not easily swell with water, and has film-forming properties, but examples include vinyl alcohol-based resins, vinyl acetate-based resins, etc. For resins, acrylic resins, urethane resins, amino acid resins, etc., the moisture permeability of a film (film thickness 10μ) measured by JIS Z-0208 B method is
1000g/m ² ·24hr or more is suitable. These resins are usually used dissolved in an organic solvent, and in this case, the solid content in the solution is adjusted to 10 to 50% by weight and the solution viscosity to be 100 to 20,000 CPS. Next, heat-expandable microcapsules and, if necessary, a moisture absorbent and other additives are suitably added to this solution and mixed uniformly to prepare a compound. The thermally expandable microcapsules used in the present invention are microspheres in which a vaporizable liquid is embedded in a thermoplastic resin film, and when heated to an appropriate temperature, the embedded liquid vaporizes and the pressure increases. The entire capsule expands, giving a foam with expanded volume (hereinafter abbreviated as foaming). The thermoplastic resin constituting the microcapsules preferably has a softening point of 50 to 200°C, and examples of this type of resin include polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polymethyl acrylate, and polymethyl methacrylate. , homopolymers such as polyvinyl acetate, copolymers thereof, and mixtures thereof. As the vaporizable liquid to be embedded, lower hydrocarbons such as liquefied butane, which can be easily microencapsulated and are inexpensive, are suitable. The particle size of microcapsules before foaming is 5 to 30μ, which is 50 to 30μ.
It has the property of foaming several to several tens of times more when heated at 200°C for several minutes. The above mixing ratio of thermally expandable microcapsules and moisture permeable resin is per 100 parts by weight of resin solid content in the solution.
Microcapsules range from 10 to 500 parts by weight.
If it is less than 10 parts by weight, it will lack a soft feel especially as wallpaper after foaming, and if it is more than 500 parts by weight, the strength of the moisture permeable resin foam layer will be weak and the moisture permeability will be impaired, which is not preferable. When mixing the microcapsules, it is important to use an appropriate method such as a dissolver, a homodisper, or a paint roll to uniformly mix and disperse the microcapsules. As the moisture absorbent used in the upper layer in the present invention, any known polymeric moisture absorbent or inorganic moisture absorbent that can exhibit moisture absorption and desorption performance depending on the environment can be used. , each of them may be used alone or in combination. Preferred polymeric moisture absorbers include known superabsorbent resins, such as polyacrylates,
Carboxymethylose, isobutylene-maleic acid copolymer, starch-acrylic acid graft polymer,
Examples include saponified vinyl acetate-acrylic acid ester copolymer and polyethylene oxide moisture absorbent. The dry particle size of these polymeric moisture absorbers is usually 20 μm or less, and the finer the particle size, the better the moisture absorption and release performance, which is preferable. Moreover, these polymeric moisture absorbents have a water absorption capacity of 2 to 200 times, and those with a water absorption capacity of 5 to 100 times are particularly preferable. In addition, bentonite, silica gel, sepiolite, calcined talc, zeolite, various other inorganic salts, and natural stone powder with adsorption properties are used as inorganic moisture absorbers, but the smaller the particle size of these, the larger the surface area. It is preferable because it has good moisture absorption and desorption performance. On the other hand, as the moisture absorbent used in the lower layer, the above-mentioned polymer moisture absorbent having a water absorption capacity of 200 times or more and capable of exhibiting moisture absorption and desorption performance depending on the environment can be used. Preferred polymeric moisture absorbers include known superabsorbent resins as in the case of topcoating, including polyacrylates, carboxymethyl cellulose, isobutylene-maleic acid copolymers, starch-acrylic acid graft polymers, and vinyl acetate. -Saponified acrylic ester copolymers, polyethylene oxide moisture absorbents, etc. can be exemplified. The dry particle size of these polymeric moisture absorbers is also usually 20 μm or less, as in the top coating, and the finer the particle size as possible, the better the moisture absorption and release performance. The amount of these moisture absorbers added is based on the resin solid content in the solution.
The content is usually preferably in the range of 10 to 300 parts by weight per 100 parts by weight, and is selected so that the moisture absorption and desorption performance of the wallpaper is maximized as long as other properties are not impaired. In carrying out this invention, in addition to the above compounding agents, various pigments, weathering agents, fragrances, antifungal agents,
Flame retardants and the like can be added as appropriate. As a method for mixing the various compounding ingredients as described above and applying the prepared compound to the wallpaper mount, known coating methods such as gravure coating, doctor blade coating, reverse roll coating, etc. can be appropriately employed. Flame-retardant pulp paper is usually used as wallpaper mount, but it may also be pulp paper without flame-retardant treatment, processed pulp paper, or mount made of organic or inorganic synthetic paper or nonwoven fabric. The thickness of these mounts is usually 100 to 1000μ, and on top of this, the undercoat compound is continuously applied to a constant thickness of 10 to 100μ and dried, and on top of that, two coats of topcoat compound are applied.
When it is continuously applied to a constant thickness of ~50μ and dried and heated to a predetermined temperature, the microcapsules expand and the upper and lower layers foam together, forming a moisture permeable resin foam layer with a thickness of 50 to 1000μ. If necessary, the lower layer may be foamed first, and then the upper layer may be overcoated and foamed. The heating temperature during foaming is appropriately selected depending on the material of the microcapsules used, but usually 50 to 200°C is used, and if heated at this temperature for several minutes (for example, 1 minute at 120°C), Foaming occurs as the solvent scatters, and then cooling and solidification complete the molding. Alternatively, the process of evaporating the solvent and the process of foaming can be separated to perform molding in two stages. Foaming may be free foaming, but it is also possible to control the foaming thickness by pressing with a suitable method from a roll or upper part through a release paper. In addition, as a decorative method for the wallpaper surface, embossing the coating surface after molding, various colors,
It is sufficient to print the pattern, and various methods can be used, such as using a pre-printed mount, or foaming a cord on decorative paper and laminating it with a flame-retardant lining paper. [Function] Since at least the lower layer of the wallpaper of the present invention is a foam made of closed cells, it exhibits heat insulating properties and a dew condensation prevention effect. In addition, the lower layer has a moisture absorbing agent with extremely high reversible moisture absorption and desorption properties in the moisture permeable resin foam layer, and the upper layer has a moisture absorption agent that has a relatively lower reversible moisture absorption and desorption ability than the moisture absorbent in the moisture permeable resin layer or the lower layer. With this structure, a moisture absorption/desorption cycle occurs quickly in the moisture absorbent through the moisture permeable resin depending on the indoor environment, and the dew condensation prevention effect can be further improved. Moreover, the wallpaper can be made without stickiness on the surface. When wallpaper with this structure is attached to indoor walls, etc., the insulating effect of the closed cells can delay and prevent the formation of condensation, and even when the indoor humidity is high, water vapor can pass through the moisture-permeable resin layer. Penetrates inside the wallpaper, especially the lower layer,
It is temporarily occluded by a polymer moisture absorbent with a high water absorption rate filled inside the resin layer. When the indoor air becomes dry, the moisture that has been absorbed once again passes through the moisture-permeable resin layer and is immediately released into the room from the wallpaper surface, reversibly absorbing and desorbing moisture in accordance with changes in indoor humidity. It has a humidity buffering effect. In the present invention, as a result of the presence of closed cells and their moisture absorption/desorption effect, dew condensation on the wall surface can be permanently and effectively suppressed. Furthermore, since the lower layer foam is closed-celled, the surface is non-porous and does not get clogged even if dirt adheres to it. Moreover, since a top coat layer that does not become sticky when water is absorbed is applied, the surface does not become sticky, and stains can be easily wiped off with a dry cloth or damp cloth, so that the product maintains its beautiful appearance for a long time and does not reduce its moisture permeability. When the wallpaper of the present invention is used in combination with an appropriate heat insulating material such as phenol board, urethane board, or styrene board, the wallpaper feels similar to leather because it is composed of a moisture-permeable resin foam made of closed cells. etc., the texture is extremely good. [Example] Examples 1 to 3 Polyethylene glycol (average molecular weight 400) and isophorone diisocyanate were polymerized by heating in a conventional manner, and the obtained urethane polymer was dissolved in a toluene-isopropanol mixed solvent (weight mixing ratio 1:1). A urethane polymer solution with a solid content of 25% by weight was prepared. The moisture permeability of a 20μ thick film made from this solution by the casting method is 4300g/
It was ^m2・24hr. Next, to this solution, per 100 parts by weight of the solid content, 80 parts by weight of thermally expandable microcapsules (trade name: Microsphere F-50D, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) and a polymer hygroscopic agent (Sumitomo Manufactured by Kagaku Kogyo Co., Ltd., Sumikagel NP1010) or PS510, or Sunwet
IM300 (Sanyo Kasei Co., Ltd.) was added at a ratio of 30 parts by weight, and mixed uniformly using a paint roll to prepare a compound. This compound was applied uniformly onto flame retardant wallpaper paper (thickness 170μ) using the gravure coating method and placed in a heating oven.
It was dried at 50°C for 20 minutes to obtain a lower layer with a coating thickness of 60μ.
On top of that, the above urethane polymer solution with a solid content of 25% by weight was applied by gravure coating to a solid content of 15μ.
Apply it evenly to a thickness and heat it in a heating oven at 140℃.
By heating and foaming for 1 minute and then cooling,
A wallpaper with a thickness of 500 μm was obtained by laminating and fixing a moisture permeable resin foam layer consisting of substantially closed cells on the surface of a wallpaper mount. FIG. 1 is a sectional view showing the structure of a moisture-permeable anti-condensation wallpaper obtained by the above method. In FIG. 1, 1 is an upper layer of moisture-permeable resin, 2 is a lower layer of moisture-permeable resin foam, and 3 is a wallpaper mount made of flame-retardant paper. As shown in the figure, in the lower layer 2 of the moisture permeable resin foam, there are closed cells 5 formed in the moisture permeable resin 4 by heating the thermally expandable microcapsules. In this embodiment, the closed cell 5 has its outer periphery covered with a thermoplastic resin film 6 forming a boundary with the moisture permeable resin 4. Note that 7 is a highly hygroscopic moisture absorbent having a water absorption capacity of 200 times or more, which is dispersed and embedded in the moisture permeable resin 4 of the lower layer 2 of the moisture permeable resin foam. Therefore, as shown in FIG. 6, when the indoor humidity is high, the water vapor 8 shown by the arrow in the figure penetrates the moisture permeable resin of the upper layer 1 and penetrates into the interior, and further penetrates the moisture permeable resin 4 of the lower layer 2. It permeates and is incorporated into the moisture absorbent 7 present in the moisture permeable resin 4. On the other hand, when the indoor air becomes dry, as shown in FIG. 1
The liquid then passes through the moisture-permeable resin of the upper layer 1 and is released to the outside. Therefore, it reversibly absorbs and releases moisture following changes in indoor humidity, and as a result, the phenomenon of condensation on the wall surface is suppressed. Furthermore, since the lower layer 2 has closed cells 5 covered with a thermoplastic resin film 6,
It has heat insulating properties and exhibits a dew condensation prevention effect in this respect as well. In addition, the moisture absorbent is contained in the lower layer 2 and is covered with the moisture permeable resin upper layer 1, so even though the moisture absorbent 7 is a high moisture absorbent with a water absorption rate of 200 times or more, it does not absorb water. It is not sticky at times, and dirt can be easily wiped off, and in particular, it is possible to prevent a decrease in moisture permeability due to stickiness when water is absorbed. Regarding this wallpaper, we conducted a moisture permeability test using the method below.
A dew condensation test and a moisture absorption/release test were conducted. The results are shown in Table 1 and FIG. Moisture permeability test: Measured according to JIS Z-0208 B method. Condensation test: Paste wallpaper as a test piece on the entire outside side of a round tin can with an internal volume of 500ml using vinyl acetate adhesive, fill the can with ice water at 0°C, and place it in an atmosphere of 20°C and 50% RH. The time it takes for dew to begin to form on the wallpaper surface (dew condensation time) was measured when the wallpaper was placed on the wall. Moisture absorption/desorption test: Using wallpaper cut into 10 x 10 cm pieces as a test piece, attach aluminum foil to the back of the mount to prevent water vapor from penetrating from the back, and place it in an atmosphere of 40℃ and 90% RH. We measured the amount of water absorbed by the wallpaper over time over 24 hours. The results are shown in Figure 5. 1st
In the figure, the water absorption capacity indicates the amount of water absorbed when the moisture absorbent is immersed in water, and its value is determined by weighing 1 g of the moisture absorbing agent, immersing it in water, leaving it for 24 hours, measuring the weight, and using the formula below. I asked for it. Sample weight after water absorption/Sample weight before test From the above test results, this wallpaper has high moisture permeability.
It can be seen that the time until dew condensation is long, 8 hours or more, and that the surface exhibits good moisture absorption and desorption performance with no stickiness on the surface when water is absorbed. Example 4 In Example 1, 80 parts by weight of thermally expandable microcapsules were added to a 25% solids urethane polymer solution as a top coating compound per 100 parts by weight of solids in the solution, and the mixture was added using a paint roll. The mixture was mixed uniformly to prepare a compound. Using this compound, wallpaper with a thickness of 600 μm was obtained in the same manner as in Example 1. FIG. 2 is a cross-sectional view of a moisture-permeable anti-condensation wallpaper obtained by this method. In FIG. 2, reference numerals 1 to 7 are the same as in FIG. A large number of closed cells 5 are present in the moisture permeable resin 9. Therefore, in the upper layer 1 as well as in the lower layer 2, water vapor is absorbed and released by passing through the moisture permeable resin 9 existing between the closed cells 5. In this example, since the upper layer 1 also has closed cells 5 in the moisture permeable resin 9, the heat insulation properties are increased and the dew condensation prevention effect is further improved. It is also possible to prevent stickiness and a decrease in moisture permeability due to the stickiness. Regarding this wallpaper, performance tests were conducted in the same manner as in Examples 1 to 3, and the results are shown in Table 1. Examples 5 and 6 In Example 3, a polymer moisture absorbent (Kuraray Co., Ltd., KI Gel) or bentonite was added to the urethane polymer solution with a solid content of 25% as the top coating compound per 100 parts by weight of the solid content in the solution. A compound was prepared by adding 50 parts by weight. Using this compound, by the same method as in Example 1,
A wallpaper with a thickness of 500μ was obtained. Example 5 used KI gel as a moisture absorbent in the topcoat layer, and Example 6 used bentonite as a moisture absorbent. A performance test was conducted on the obtained wallpaper in the same manner as in Example 1. The results are shown in Table 1. FIG. 3 is a sectional view of a moisture-permeable anti-condensation wallpaper obtained by this method. In FIG. 3, numerals 1 to 7 are the same as in FIG. 1, but in this embodiment, especially the moisture-permeable resin 9
It contains a moisture absorbent 10 with a water absorption rate of 20 times.
As a result, in this embodiment, the moisture absorbent 10 also in the upper layer 1 captures a part of the water vapor that passes through the moisture permeable resin of the upper layer 1, and together with the moisture absorbent 7 in the lower layer, suppresses the condensation phenomenon. Since the magnification is 20x, the surface will not be sticky.
There is no decrease in hygroscopicity due to stickiness. Example 7 In Example 5, 50 parts by weight of thermally expandable microcapsules were added as a top coating compound,
A compound was prepared. Using this compound, wallpaper with a thickness of 600 μm was obtained by the same method as in Example 1. A performance test was conducted on the obtained wallpaper in the same manner as in Example 1. The results are shown in Table 1 and Figure 5. FIG. 4 is a sectional view of a moisture-permeable anti-condensation wallpaper obtained by this method. In Fig. 4, the numbers 1 to 7 are the same as in Fig. 1, 1 is an upper layer of moisture permeable resin, 2 is a lower layer of moisture permeable resin foam, 3 is a wallpaper mount made of flame retardant paper, and 4 is a moisture permeable resin foam. 5 is a resin, 5 is a closed cell, 6 is a thermoplastic resin film, and 7 is a moisture absorbent with a water absorption capacity of 200 times or more. This embodiment has 5 closed cells in the moisture permeable resin 9 of the upper layer 1.
It is different from the above embodiment in that it has both a moisture absorbent 10 with a water absorption capacity of 20 times, and the moisture absorbing and releasing properties of the heat insulating property of the upper layer 1 are further improved. Comparative Examples 1, 2, 3 A commercially available polyvinyl chloride wallpaper that does not contain a moisture absorbent, a commercially available polyvinyl chloride wallpaper that contains a polymer moisture absorbent, and the moisture permeable resin and a water absorption capacity of 2 to 2.
A moisture-permeable anti-condensation wallpaper was prepared by uniformly mixing a 200 times larger polymer KI gel moisture absorbent and the microcapsules, applying the resulting compound to the surface of the wallpaper, and heating and foaming it. A humidity test, a dew condensation test, and a moisture absorption/release test were conducted.
The results are shown in Table 1 and FIG. 5 as Comparative Examples 1, 2, and 3. As shown in Table 1, all of the wallpapers of the present invention have moisture permeability of 2000 g/m ² · 24 hr. or more, which is significantly higher than that of commercially available vinyl chloride wallpapers.
In the dew condensation test, the time until condensation occurred was as long as 8 hours or more, and the product had sufficient dew condensation prevention performance, and as shown in FIG. 5, the moisture absorption and release action was performed promptly. In addition, the wallpaper surface does not become sticky when water is absorbed, and it has excellent performance as wallpaper.

【table】

〔Effect of the invention〕

According to the wallpaper of the present invention, since it is a closed cell, it has excellent heat insulation properties, and since the moisture absorbent exhibits moisture absorption and release functions through the moisture permeable resin layer, it absorbs and releases moisture while retaining its heat insulation properties. The synergistic effect of both provides a good dew condensation prevention effect. In particular, the moisture-permeable resin foam layer obtained using the above-mentioned microcapsules has a superior dew condensation prevention effect, and at the same time, it is easy to manufacture, does not require special equipment, and can be manufactured at an extremely low cost. I can do it. In addition, even if a water-absorbing agent with extremely high water absorption capacity is used in the lower layer, the surface of the upper layer will not become sticky, and at the same time it has excellent stain resistance, it can also prevent a decrease in moisture permeability, and it also has an excellent texture. There are some very significant contributions to the field.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an example of the moisture permeable dew condensation prevention wallpaper of the present invention, FIGS. 2 to 4 are sectional views of other embodiments of the wallpaper of the present invention, and FIG. 5 is an example of the present invention and a comparison. Graphs illustrating the moisture absorption and desorption performance measured for the example wallpaper, and FIGS. 6 and 7 are cross-sectional views conceptually showing the state in which water vapor absorbs and desorbs moisture using the wallpaper in FIG. 1. 1...upper layer, 2...lower layer, 3...wallpaper mount,
4... Moisture permeable resin, 5... Closed cell, 6... Thermoplastic resin film, 7... Moisture absorbent, 9... Moisture permeable resin,
10... Moisture absorbent.

Claims (1)

[Claims] 1. A lower layer of moisture permeable resin foam made of closed cells in which a polymeric moisture absorbent with a water absorption capacity of 200 times or more is dispersed and embedded on the surface of a wallpaper mount, and a moisture permeable resin foam as the main component. , a moisture-permeable dew-preventing wallpaper characterized by laminating and fixing an upper layer covering a lower layer of the moisture-permeable resin foam. 2. The moisture-permeable anti-condensation wallpaper according to claim 1, wherein the closed cells are foams composed of a thermoplastic resin film of thermally expanded microcapsules. 3. The moisture-permeable anti-condensation wallpaper according to claim 1 or 2, wherein the upper layer is a moisture-permeable resin layer or a moisture-permeable resin foam layer consisting of closed cells. 4. The moisture permeable anti-condensation wallpaper according to claim 1, 2 or 3, wherein an organic or inorganic moisture absorbent having a water absorption capacity of 2 to 200 times is dispersed and embedded in the moisture permeable resin of the upper layer. 5 Heat-expandable microcapsules made by embedding a vaporizable liquid in thermoplastic resin, a moisture-permeable resin, and a polymer moisture absorbent with a water absorption capacity of 200 times or more are uniformly mixed, and the resulting compound is used for wallpaper. A method for producing moisture-permeable anti-condensation wallpaper, characterized in that the surface of a mount is undercoated, a compound mainly composed of a moisture-permeable resin is overcoated, and the mixture is heated and foamed. 6. The method for producing moisture permeable anti-condensation wallpaper according to claim 5, wherein the top coating compound contains thermally expandable microcapsules formed by embedding a vaporizable liquid in a thermoplastic resin. 7. Water absorption rate 2~2 for topcoat compound
7. The method for producing moisture-permeable dew condensation-preventing wallpaper according to claim 5 or 6, wherein 200 times as much organic or inorganic moisture absorbent is mixed.