JPH0343058B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for manufacturing a dew-preventing foam decorative material having an uneven pattern. <Prior Art> There are the following three methods known as methods for imparting a dew condensation prevention effect to decorative materials using synthetic resins. That is, one is to mix a water-absorbing polymer into the synthetic resin layer as disclosed in JP-A No. 56-3302, and the other is to mix a water-absorbing polymer into the synthetic resin layer as disclosed in JP-A-53-31772. As described in Japanese Patent Publication No. 53-38102, one method is to create a foam layer with countless interconnected micro-cells, and the other is to create a foam layer with an olefin-based microporous sheet to improve moisture permeability. It's about making it last. <Problems to be Solved by the Invention> Since these decorative materials are mainly used as interior wall covering materials, they are usually given an uneven pattern using a mechanical embossing device. The dew condensation prevention effect was significantly impaired, and the desired dew condensation prevention effect could not be exhibited. In the method of mixing water-absorbing polymers into the synthetic resin layer, the water-absorbing effect only works on the water-absorbing polymers exposed on the surface. However, when mechanical embossing is applied to obtain a decorative design, the surface The exposed area of the water-absorbing polymer that had been exposed to the water became narrower, or in extreme cases it was crushed, making it impossible to expect the original dew condensation prevention effect. In addition, when mechanical embossing is applied to a foamed layer with countless interconnected microbubbles to ensure the design, the foamed synthetic resin layer melts due to the heating during embossing, and the interconnecting microbubbles disappear. In addition, the mechanical pressure during embossing crushed the communicating microbubbles in the concave portions, and the desired dew condensation prevention effect could not be obtained. In addition, even if the olefin-based microporous sheet is made moisture permeable, if mechanical embossing is applied to ensure the design as an interior material, the heating during embossing melts the micropores in the sheet and closes them. In the concave portions that are exposed to mechanical pressure during embossing, the micropores are crushed, and there is a risk that the desired moisture permeability effect will be significantly impaired. In addition, as a method for creating an uneven pattern that does not involve mechanical embossing, there is a method for creating an uneven pattern described in Japanese Patent Publication No. 59-1580. It is excellent in that it can create uneven patterns. Therefore, the present invention provides a method for creating a foam uneven pattern that has only the three advantages of a water-absorbing polymer, a foam layer with communicating microbubbles, and a moisture-permeable resin, and a hollow core portion created by the difference in decomposition temperature of the foaming agent. The purpose of this work is to provide a method for producing an extremely excellent dew-preventing foam decorative material by skillfully combining the following methods. <Means for solving the problems> The present invention will be described in detail as follows. In synthetic resin foaming methods that use blowing agents, decomposable blowing agents are widely used as blowing agents, and such decomposable blowing agents include organic blowing agents such as azo compounds, sulfohydrazide compounds, nitroso compounds, and azizo compounds. It is well known that there are other inorganic blowing agents in addition to foaming agents, each with different decomposition temperatures and amounts of decomposed gas generated. In general, the decomposition temperature is determined by the amount of synthetic resin or its raw materials, plasticizers, solvents, stabilizers,
For example, azodicarbonamide (ADCA) changes greatly when mixed with acids, bases, etc., or especially when a blowing agent is dissolved in the compounding agent.
The decomposition temperature of the oxybisbenzenesulfonyl hydrazide (OBSH) system is around 130°C, whereas the decomposition temperature of the oxybisbenzenesulfonyl hydrazide (OBSH) system is around 130°C. Choosing a degradable blowing agent is easy. Therefore, a first foaming agent-containing synthetic resin layer is formed in an arbitrary pattern on the base material surface, and this is then coated with a second foaming agent-containing synthetic resin layer having a decomposition temperature higher than the decomposition temperature of the first foaming agent. The material is coated with a synthetic resin layer containing a water-absorbing polymer, and then a moisture-permeable resin film is formed on top of the layer, which is then heated and foamed.This second foaming agent is used to prevent condensation. It is necessary to have an open cell ratio of 70% or more in the state after foaming, and the adjustment of the ratio to create countless interconnected fine cells (open cells) is done by using a blowing agent for closed cell formation and an open cell ratio (open cells). This can be achieved by adjusting the mixing ratio with the foaming agent for forming open-cell foams, or by adjusting the foaming speed by selecting a stabilizer, or by adjusting the foaming heating temperature and foaming heating time. The above-mentioned Japanese Patent Application Publication No. 1973-
Publication No. 31772 gives examples of a combination of a foaming agent (Uniform AZ-F Otsuka Pharmaceutical) and a stabilizer (Stabilizer-F Kyodo Pharmaceutical), and a combination of a foaming agent (Onifain MO Otsuka Pharmaceutical) and any stabilizer. Also in the case of the present invention, these agents can be used as the second blowing agent. In the case of vinyl chloride resin, the first blowing agent is an oxybisbenzenesulfonylhydrazide (OBSH) blowing agent, and the second blowing agent that forms open cells is an azocycarbonamide (ADCA) blowing agent. is often used. The water-absorbing polymer contained in the second synthetic resin layer is a well-known hydrophilic resin that can absorb water and expand.
It is desirable to have the ability to absorb 50 times more pure water. Main water-absorbing polymers include starch/sodium acrylate graft copolymers, saponified vinyl esters/ethylenically unsaturated carboxylic acids or their derivatives, polysodium acrylate crosslinkers, and polyvinyl alcohol/acrylate graft copolymers. Examples include polymers. Commercially available products include Sumikagel-SP (Sumitomo Chemical), Sunwet IM-300 (Sanyo Chemical), and Aqua Keep 4S.
(steel manufacturing chemical industry products), etc. These water-absorbing polymers are usually fine powders with a particle size of about 350 to 0.1 μm, but in consideration of dispersibility, the average particle size is preferably 100 μm or less. The number of parts added is usually 2 to 40 parts, preferably around 5 to 15 parts. As the moisture-permeable resin, for example, urethane-based W/O
Type emulsion resin, amino acid/methacrylic acid/
In addition to urethane copolymers, microporous sheets of the above-mentioned olefin resins are listed, but they do not lose their moisture-permeable resin performance at the temperature of heating and foaming, and are also used as wall covering materials. Also, cleaning waste water seeps in when wiping it when it gets dirty,
Depending on the relationship between room temperature, humidity, and the surface temperature of the wall covering material,
Preferred is an amino acid/methacrylic acid/urethane copolymer that allows indoor moisture to pass through only in the form of water vapor on the verge of condensation, but not in liquid form, but has properties similar to those described above. Moisture-permeable resin may also be used. In order to form a moisture-permeable resin film on the second synthetic resin layer on the base material, a moisture-permeable resin paint is applied by a coating method, or by a known method such as a gravure printing method, or A pre-formed moisture permeable resin film may be laminated. A combination of the above-mentioned water-absorbing polymer and the second foaming agent, which communicate with each other, and a moisture-permeable resin coating, without using mechanical embossing,
The inventor of the present invention discovered that by combining the manufacturing method of a foamed decorative material that can obtain a remarkable difference in unevenness, it is possible to exhibit a far superior dew condensation prevention effect than the dew condensation prevention decorative materials made by conventional techniques. This is the manufacturing method. Therefore, the present invention will be explained in each step.
As shown in the figure, a first synthetic resin layer 2 containing a first foaming agent is formed in a pattern on one surface of a base material such as paper or cloth by, for example, printing, and this is coated with fine powdery water-absorbing material. coated with a second synthetic resin layer 3 containing a second blowing agent which has a decomposition temperature higher than that of the polymer and the blowing agent and which forms countless interconnected micro-cells after heating and foaming; The moisture-permeable resin coating 4 formed on the second synthetic resin layer was subjected to a heat foaming treatment. The foaming of the first and second synthetic resin layers at this time is shown in Figure 1-B showing the initial stage, Figure 1-C showing the intermediate stage, and Figure 1-C showing the final stage.
The process was completed through the state shown in Figure D, and in the end, the first synthetic resin layer 2, which had been formed in a pattern, was foamed while the second synthetic resin layer 3 still maintained its airtightness. The hollow core portion 5 is used to bulge out, and each step will be specifically explained as follows. At the initial stage of foaming shown in Figure 1-B, the first foaming agent in the first synthetic resin layer 2 has already started to decompose and generate decomposed gas, but the second foaming agent covering it has already begun to decompose and generate decomposed gas.
The second foaming agent in the synthetic resin layer 3 has not yet decomposed and the sealed membrane state is maintained, so the decomposed gas from the first synthetic resin layer 2 is not released to the outside. It cannot escape and has no choice but to push the second synthetic resin layer 3 upward and swell. In this process, minute cells (bubbles) are scattered inside the first synthetic resin layer 2, but as the foaming progresses, the minute cells grow larger, and furthermore, adjacent cells connect with each other, causing the first synthetic resin layer 2 to become larger. It turns into a collection of multiple coarse cells as shown in Figure C. When the state shown in Fig. 1-C is reached, the second foaming agent in the second synthetic resin layer 3 has gradually begun to decompose, but in this state it has not yet become an open cell, so the first The above-mentioned push-up continues to grow until the decomposition gas from the synthetic resin layer 2 can freely escape. In the final stage of foaming shown in FIG. 1-D, when the plurality of coarse cells finally become one large bubble and form the hollow core portion 5, the second synthetic resin layer 3 is foamed with an appropriate foaming ratio. In the final stage, the foam layer becomes a foam layer with countless interconnected microscopic cells. The size of the hollow core portion 5, which dramatically increases the swelling effect, depends on the amount of decomposed gas from the first blowing agent contained in the first synthetic resin layer 2. The amount of the first blowing agent may be appropriately determined in relation to the desired size of the hollow core portion 5. In addition, if the difference in decomposition temperature between the first and second foaming agents is small, there will be little deviation in the foaming states of both resins, and air bubbles communicating with the second synthetic resin layer will be formed at an intermediate stage, causing the inner The decomposed gas of the first blowing agent cannot be held inside and easily escapes to the outside, making it impossible to expect much from the expansion effect of the hollow core portion 5, so the difference is at least 30°C. It is preferable that it is above. but,
If the foaming heating furnace used for foaming heat treatment has multiple chambers, preferably a three-chamber type, and the temperature is precisely adjusted according to the initial, middle, and final stages, the first and second foaming It is possible even if the difference in decomposition temperature of the agent is less than 30°C. In addition, as a method for applying the first synthetic resin layer 2 in a pattern on the base material surface, a known pattern application/printing method such as a gravure printer, a rotary screen printer, a screen printer, etc. can be used. The second synthetic resin layer 3 containing a water-absorbing polymer and a second foaming agent can be formed by a known coating method such as a coating machine such as a roll coater or a knife coater or a rotary screen printer. The resin layer 3 may be formed into a sheet shape in advance, and this sheet may be pasted in a pattern onto the base material 1 on which the first synthetic resin layer 2 is applied. As the base material, any material can be used, such as paper, cloth, nonwoven fabric, aluminum hydroxide paper, synthetic paper, polysand paper with a polyethylene film layer provided therebetween. Further, as the resin used for the first and second synthetic resin layers, any resin including heat-foamable vinyl chloride resin can be used. <Effects of the Invention> According to the method of the present invention, the first synthetic resin layer containing a foaming agent is coated with the second synthetic resin layer 3 containing a foaming agent for forming the surface textured foam layer. 2 is foamed while the second synthetic resin layer 3 still maintains its airtightness due to the difference in the decomposition temperature of the foaming agent.
When the second synthetic resin layer 3 forms a surface foam layer by actively expanding from fine cells to coarse cells and from coarse cells to a single hollow core portion 5, the hollow core portion 5 is expanded. The point that it is possible to reliably obtain a dew-preventing foam decorative material that is swollen by an interposition and has an extremely large difference in unevenness, which is two to three times as large as that of ordinary foam decorative materials, without mechanical embossing. It's extremely good. In particular, the countless interconnected microbubbles formed in the second synthetic resin layer 3 at the final stage of foaming are not crushed at all during the uneven pattern creation process, so the dew condensation prevention effect is not impaired. It is also extremely good in that respect. Especially in concave and convex areas, the synthetic resin layer 3
The microbubbles that communicate with each other exist as they are, and the water-absorbing polymer is not crushed at all, so it is extremely superior in that it can perform its functions at 100%. In the conventional method of processing a condensation-preventing decorative material, it is not possible to obtain the same unevenness level difference as in the present invention while maintaining the same dew-condensation-preventing effect as in the present invention. Furthermore, even if the volume of the concavities and convexities is the same as in the conventional method, the method of the present invention requires only about half the material, and the condensation prevention effect is superior to that of the conventional method. Furthermore, even if the water-absorbing polymer in the synthetic resin layer 3 becomes saturated due to moisture absorption, the moisture becomes internally condensed in the hollow core portion 5 and is retained as water droplets, so that the moisture absorption ability is enhanced. Therefore, it is also extremely superior in that there is no condensation on the surface. The size of this hollow core portion 5 is much larger than the average particle diameter of the water-absorbing polymer, and the moisture absorption ability after the water-absorbing polymer is saturated also depends on the number and size of the hollow core portions. However, it is 5 to 10 times as much as the one without a hollow core, which is extremely superior. According to the method of the present invention, fine powdery water-absorbing polymers are almost uniformly scattered in the foamed synthetic resin layer in which a concavo-convex pattern with communicating microbubbles is formed, and further inside the convex portions. has a hollow core. Moreover, the surface of the foamed synthetic resin layer with its uneven pattern is covered with a moisture permeable resin, so even if dew condensation occurs on the surface, the moisture will pass through the moisture permeable resin coating layer and connect the foamed synthetic resin layer. Since the water is actively absorbed by the microbubbles and water-absorbing polymer, there is no possibility of condensation forming, and therefore there is no possibility that condensed water will adhere to the concave parts of the foamed uneven pattern or flow down the surface. There is no.
In particular, as mentioned above, when the water-absorbing ability of the water-absorbing polymer reaches a saturated state, moisture accumulates in the form of water droplets within the hollow core. It is also possible to reduce the amount to an extremely low level, which is extremely superior to conventional techniques. In addition, when using the method of the present invention, if a known antibacterial agent or antifungal agent is added in advance to the synthetic resin compound that will become the foamed synthetic resin layer 3, mold and the like will grow due to the absorbed moisture, resulting in discoloration. There is no risk of doing so. In this case, if possible, it is desirable to add a known antibacterial agent or antifungal agent to the moisture permeable resin coating. Furthermore, when the foamed decorative material of the present invention is used as wallpaper, it not only has the effect of preventing dew condensation, but also prevents moisture (moisture) absorbed inside the foamed synthetic resin layer when the room is extremely dry. Due to the capillary phenomenon of the communicating microbubbles, it passes through the moisture-permeable resin coating layer and is gradually released into the indoor air, which also exerts a humidity adjustment effect. This humidity control effect is affected by the indoor temperature and humidity, the surface temperature of the foamed decorative material on the wall, and the total amount of moisture (moisture) contained in the foamed synthetic resin layer. It also depends on the state of existence of microbubbles (number and size of bubbles, communication rate, etc.) and the thickness of the foamed synthetic resin layer. Although the present invention was made to obtain a dew condensation prevention effect, if the above-mentioned humidity control effect is actively expected, the amount of foaming agent added to create open-cell foam, and the amount of foaming agent to create open-cell foam may be changed. What is necessary is to adjust the heat treatment. Further, according to the method of the present invention, even when moisture is released, since the moisture-permeable resin film is present on the surface, it is also excellent in that no water droplets are generated on the surface of the foamed decorative material. According to the method of the present invention, the shape and width (area) of the convex portions can be set arbitrarily depending on the pattern size and coating thickness of the first foaming agent-containing synthetic resin layer provided on the base material surface. Since the part is also a foamed synthetic resin layer containing countless interconnected microbubbles and water-absorbing polymers, its moisture-absorbing ability is more than fully demonstrated. 53−
It can be said that the method disclosed in Japanese Patent No. 31772 is extremely superior in that it does not require mechanical embossing when providing an uneven pattern. In particular, when used as wallpaper, it is necessary to ensure a good design, and conventional decorative materials that prevent condensation cannot be used as wallpaper.
Without mechanical embossing, it is not possible to obtain a large uneven pattern, and mechanical embossing seriously impairs the dew condensation prevention effect in the concave areas, making it difficult to achieve both design and dew condensation prevention function. Nakatsuta. According to the method of the present invention, it is possible to obtain a foamed decorative material in which the concave portions are also foamed synthetic resin layers, and which have unevenness levels that cannot be obtained by mechanical embossing. It is also excellent in that there is no risk of deterioration of the dew condensation prevention effect. <Example> First, flame-retardant polysand paper for wallpaper 1 having a thickness of about 0.15 mm with a polyethylene film layer present in the middle.
The first polyvinyl chloride resin paint containing a blowing agent (decomposition temperature of the blowing agent: 130°C) shown in Formulation Table A was printed and coated in a hexagonal pattern using a rotary screen machine. 2 shows the coating layer of the first blowing agent-containing polyvinyl chloride resin paint. The thickness of the coating layer 2 was about 0.04 mm, and the coating amount per m ² was extremely small. The polysand paper 1 on which the coating amount 2 has been formed into a pattern is then guided into a drying oven at 120°C and passed for 60 seconds to dry and semi-gel the coating layer 2, and then transferred to a known doctor knife type coating machine. Then, a polyvinyl chloride resin paint (decomposition temperature of the blowing agent: 210° C.) containing a second blowing agent shown in Formulation Table B and a finely powdered water-absorbing polymer was applied evenly over the entire surface.
3 indicates the coating layer of the second blowing agent and the water-absorbing polymer-containing polyvinyl chloride resin paint. The thickness of the coating layer 3 was a normal coating layer thickness of about 0.15 mm. In this way, the coating layer 2 formed in a pattern
Polysand paper 1 with coating layer 3 laminated on top of
It was guided into a drying oven at 120℃ and passed for 90 seconds.
The coating layer 3 was dried and semi-gelled. Next, on this coating layer 3, using a gravure printing machine, an amino acid/
A moisture permeable resin layer 4 was formed by applying and drying a moisture permeable resin paint made of methacrylic acid/urethane copolymer. Subsequently, this was heated in a foaming furnace at 230° C. for 70 seconds to heat and foam the first and second foaming agent-containing polyvinyl chloride resin layers. The obtained product had a tortoise shell pattern that stood out in three dimensions, and its height was approximately 4 mm. In addition, from the cut end surface, it can be clearly seen that communicating microbubbles and a hollow core portion 5 are formed, and that the convex portion is raised by the hollow core portion 5, and the concave portion is also connected to countless others. It was confirmed that there were microscopic bubbles. Mixing table A PVC 100 parts DOP 70 parts Stabilizer (Ba-Zn type) 3 parts Foaming agent (OBSH type) 20 parts Foaming aid 1 part Mixing table B PVC 100 parts DOP 28 parts Flame retardant plasticizer 20 parts Epoxy type Plasticizer 2 parts Stabilizer (Ba-Zn type) 3 parts Foaming agent (ADCA type) 5 parts Filler (calcium carbonate) 50 parts Water-absorbing polymer (Sumikagel SP) 10 parts Foaming aid 1.1 parts Antibacterial/anti-mold Agent: 0.1 part Pigment (titanium white): 20 parts Table 1 shows the test results of a comparison between this example and a conventional dew-preventing wallpaper.

【table】

【table】 [Brief explanation of drawings]

1-A to 1-D are sectional views for explaining different stages from before foaming to after foaming in the manufacturing method of the present invention. 1... Polysand paper (base material), 2... Synthetic resin layer containing a first blowing agent, 3... Synthetic resin layer containing a water-absorbing polymer and a second blowing agent, 4... Moisture permeable resin Layer 5... hollow core part.

Claims (1)

[Claims] 1. The first foaming agent-containing synthetic resin layer formed in a pattern on the base material surface is heated and foamed at a decomposition temperature higher than that of the fine powder water-absorbing polymer and the foaming agent, and then the foaming layer is formed into countless interconnections. The second synthetic resin layer is coated with a synthetic resin layer containing a second foaming agent that forms microbubbles, and then a moisture-permeable resin film is formed on the second synthetic resin layer, which is further heated and foamed. The surface layer of the synthetic resin layer containing the second foaming agent and water-absorbing polymer is covered with traces of foaming of the first synthetic resin layer while the second synthetic resin layer still maintains its airtightness. A method for producing a condensation-preventing foam decorative material having an uneven pattern characterized by bulging from a certain hollow core.