JP2009068939A - Water wetting sensing sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water wetting sensing sheet pasted on an electric product or a transport cargo to accurately sense wetting in a case exposed to a rainfall or submerged in water to be wetted with water. <P>SOLUTION: The water wetting detection sheet is constituted by laminating at least a detection layer, which is composed of a silicon oxide film with a carbon atom content of ≥10 and <30% and wetted with water to be dissolved, and a release layer released accompanied by the dissolution of the detection layer on the resin surface of a base material at least one surface of which comprises a resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is mainly applied to electrical appliances or transportation luggage used outdoors, and when they are exposed to rain or submerged, it is possible to accurately detect whether or not water has been wet. It relates to a detection sheet.

  Electrical products that are used outdoors such as portable radios, video cameras, pagers, and mobile phones have a relatively high risk of getting wet in the rain or splashing water. .

  However, if it is accidentally dropped into a puddle or dropped into a container filled with water, water will enter the inside, no matter how water resistance is taken into account, and the circuit etc. will get wet and the function as an electrical product May be damaged. Such a failure is subject to paid repair as a result of carelessness of the user, that is, a general consumer.

  However, it is difficult to determine whether the failure is due to water intrusion or whether it is caused by normal use, and there may be a problem between the consumer and the manufacturer over the cause of the failure and the burden of repair costs. It was.

  Therefore, for example, as shown in FIG. 4, a water-soluble colored layer 47 made of a water-soluble colored resin in which a coloring material 48 such as a dye or a pigment is mixed (dissolved or dispersed) in a water-soluble resin on a base material 41. The water wetness detection label provided is affixed to the internal side surface 45 of the product in advance via the adhesive layer 44, and if a failure occurs, the state of the label is observed. It is confirmed whether or not. That is, when water acts on the colored layer 47 on the label surface due to water wetting, color bleeding or discoloration occurs in the coloring layer 47. The occurrence of bleeding or discoloration at this time is confirmed to detect water wetting. Yes.

  The conventional water wetting detection sheet used in this way is designed on the assumption that it can detect water wetting when the device on which it is attached is completely submerged and the interior is filled with water. Yes. However, it is impossible to detect the wetness that has been exposed to rain for a short time or the water has been accidentally applied, and even if it is a failure due to water, the evidence is included in the detection label. All that was left was the cause of trouble with regard to warranty liability during repairs.

  Therefore, when such a conventional water wetness detection sheet is attached to the outer surface of a device or the like so that slight water wettability can also be detected, the dye in the colored layer 47 is discolored before being wetted by ultraviolet rays. As a result, it was often impossible to detect the expected water wetting. Therefore, in order to detect water wetting by attaching a water wetting detection sheet externally, the coloring material in the colored layer has excellent weather resistance and water solubility. However, it was not easy to find a colorant having both.

  For example, in the conventional technique as shown in Patent Document 1, as shown in FIG. 4, the dissolution rate of the colored layer 47 is determined by the relationship between the immersion time and the temperature in the water-soluble resin used as the binder. However, when the water was slightly wet, the coloring material 48 mainly composed of a dye was slightly dissolved, and it was very difficult to determine the water wet.

Further, in Patent Document 2, as shown in FIG. 5, for the purpose of assisting the disappearance of the colored layer 57, a water-soluble resin layer 59 is provided on the substrate 51, and the colored layer 57 is placed thereon. Although the interface of the water-soluble resin layer 59 is dissolved when it is slightly wetted, the central portion is not changed and the colored layer 57 does not separate due to the viscosity of the dissolved portion, so that it can be dried. In this case, it was possible to determine whether the water was slightly wet.
Japanese Patent Laid-Open No. 9-325698 JP-A-7-144478

  This invention is made in view of the fault of the prior art which concerns, and makes it a subject to provide the water-wetting detection sheet | seat which enabled it to detect water-wetting reliably even if it wets for a short time.

  In order to achieve the above-described problems, the invention according to claim 1 is an oxidation in which at least one surface has a carbon atom content of 10% or more and less than 30% on a resin surface of a base material made of resin. A water-wetness detection sheet comprising a silicon layer and a detection layer that dissolves when wetted with water and a release layer that peels off when the detection layer dissolves.

  The invention according to claim 2 is the water wetting detection sheet according to claim 1, wherein the detection layer is laminated on the release layer in a state where a part of the release layer is not covered, and the surface wetting angle thereof. Is smaller than the substrate.

  Furthermore, the invention according to claim 3 is the water wetness detection sheet according to claim 1 or 2, wherein the width of the base material in contact with the detection layer of the substrate is adjusted to a width of 0. A water flow groove of less than 1 mm is provided.

  Furthermore, the invention according to claim 4 is the water wetness detection sheet according to any one of claims 1 to 3, wherein the detection layer is formed by a plasma CVD method.

  According to the first aspect of the present invention, since the adhesion to the base material can be finely adjusted by changing the carbon atom content of the silicon oxide film constituting the detection layer, a slight amount of water that has been impossible in the past has been impossible. Wet detection is also possible. In addition, since it is not a structure in which the colored display disappears, there are few restrictions on materials used such as coloring materials, and the width of the design is widened.

  According to the second aspect of the present invention, the response speed of the water wetness detection can be improved by improving the water wettability, and the detection is possible even with less water wettability.

  According to the third aspect of the present invention, a water flow groove is provided, and the detection of the presence / absence of water wetting can be performed by improving the response speed by utilizing the capillary phenomenon, and the presence / absence of the water wetting can be reliably detected. Will be able to do.

  According to the invention of claim 4, the carbon atom content of the film is varied according to the degree of water wetting by a simple and reliable film forming method capable of generating a silicon oxide film by changing the component composition. Water wetting detection sheets having various detection sensitivities can be proposed.

  Hereinafter, the best embodiment according to the present invention will be described.

  An important feature of the water-wetting determination sheet of the present invention is that the structure in which the coloring material has disappeared in the past is used to adhere the adhesive force by water to the joint portion between the base material 1 and the peeling layer 3 on which the coloring material is placed. It is that it was set as the water wetness determination sheet | seat by arrange | positioning the composition which falls and separating the base material 1 and the peeling layer 3 by water wet. Moreover, since the detection sensitivity according to the degree of water wetting is shown by the blending, it is possible to confirm the history even with slight water wetting compared to the conventional product that senses complete submersion. In addition, although it is difficult to determine the conventional determination sheet depending on how the color material bleeds, the present invention is characterized in that determination is easy and there is no individual difference because determination is made based on whether or not the release layer is peeled off.

  FIG. 1 shows a schematic cross-sectional configuration of the water wetting detection sheet according to the present invention and its use state. This water-wetting detection sheet is formed of a silicon oxide film having a carbon atom content of 10% or more and less than 30% on the resin surface of the substrate 1 having at least one surface made of a resin, and is dissolved by water wetting. 2 and a release layer 3 that is peeled off as the detection layer 2 is dissolved. The water wetness detection sheet having such a configuration is used by being attached to the adherend 5 via the adherend adhesion layer 4.

  The base material 1 whose surface is made of resin is polyethylene, polypropylene, polystyrene, polyester, polycarbonate, vinyl chloride alcohol, ethylene vinyl alcohol copolymer, cyclic polyolefin, poly / methacryl / meta / acrylate, polyacetal, acrylonitrile / butadiene / styrene. A resin layer or a resin film layer is provided on at least one side of a sheet or film made of a resin such as paper, paper such as high-quality paper, art paper, or coated paper, or a single or multi-layer sheet made of metal or ceramic. It is provided and the one surface is comprised from the sheet-like base | substrate which consists of resin.

  Various additives such as an antioxidant, a neutralizing agent, an ultraviolet absorber, an antistatic agent, a lubricant, and a colorant may be added to the sheet or film made of the resin. However, when these additives are excessively added to cause bleeding on the surface, the detection layer 2 described below should be provided after washing once.

  The layer provided on the entire or part of the resin surface of the substrate 1 is a detection layer 2. This detection layer 2 is a layer that dissolves when wetted with water, and is a layer made of a silicon oxide film having a carbon molecule content of 10% or more and less than 30%. The thickness of the layer is arbitrary, but it may be about 20 nm.

  This detection layer 2 plays a role of separating the base material 1 and a release layer 3 described later by losing the bonding force with the adjacent layer due to water wetting. When the silicon oxide film is laminated on the resin layer, the bonding strength with the resin layer varies depending on the carbon atom content. High purity does not adhere to the surface of the resin layer, but when carbon atoms are mixed, the adhesion to the resin surface is significantly improved.

  For example, for the purpose of improving the gas barrier property of a resin container, a silicon oxide film is formed on the resin layer of the container by a plasma CVD method by reacting a raw material gas having a structure in which silicon or siloxane and a methyl group are combined with oxygen. In this case, in the initial stage of film formation, an excessive flow of source gas is performed to form a film that contributes to adhesion, and then the ratio of the source gas is changed to change the composition of the film, thereby providing various functions. A barrier layer is formed. At this time, the portion serving as the adhesive layer has a carbon atom content of between 70% and 30%, and this range has water resistance. On the other hand, the portion of the film further formed thereon has a carbon atom content of less than 10%, and the desired gas barrier property is developed in this portion. However, adhesion to the resin surface cannot be expected at such a carbon atom content.

  Therefore, as a result of measuring various films made of silicon oxide using an X-ray photoelectron spectrometer, if the carbon atom content is less than 10%, no adhesion to the resin layer can be expected, but the carbon atom content is 10%. In the range of from 30% to less than 30%, the carbon atom content is not as strong as that of the silicon oxide film in the range of 70% to 30%, but it has an appropriate binding force and dissolves when water acts. And the knowledge that the peeling layer mentioned later can be peeled reliably was acquired. That is, by setting the carbon atom content of the detection layer (silicon oxide film) to be laminated on the resin surface of the base material to 10% or more and less than 30%, even if it is slightly wet, it dissolves in water and is provided thereon. It was found that the peeling layer was peeled off, so that the presence or absence of water wetting could be detected accurately.

  Such a detection layer 2 can be provided mainly by a plasma CVD method. As a source gas that can be used in this case, hexamethyl disiloxane (hereinafter referred to as HMDSO) as a main gas, trimethyl siloxane, or the like can be used. It is possible to form a silicon oxide film of not less than 30% and less than 30%. Further, oxygen can be mainly used as the reactive gas.

  Moreover, it is preferable to laminate | stack the peeling layer 3 on the detection layer 2 in the state which does not cover a part of detection layer 2 mentioned later, and set the surface wetting angle smaller than a base material. With such a configuration, water wettability is improved, and the response speed of water wetness detection can be further improved.

  On the other hand, the release layer 3 is laminated on the detection layer having such a configuration. The release layer 3 includes a display layer 3a and an adhesive layer 3b. The display layer 3a is a film or sheet made of water-insoluble resin, or water-resistant paper, or a sheet made of metal, ceramic, or the like, or a printed layer applied to these sheets or the like. It is an insoluble layer. The display layer 3 is wetted by, for example, baking a thin film made of a composition obtained by mixing a water-soluble dye in a water-soluble resin binder at an appropriate temperature (100 ° C. to 200 ° C.). It may be obtained by adjusting the ease of dissolution to a certain extent in the direction in which it is difficult to dissolve. In addition, the display layer 3a constituting the release layer 3 needs to have a water-resistant structure so that the display layer 3a itself does not absorb moisture. Specifically, it is a cured thin film made of an ultraviolet curable resin or a layer made of paper whose end face is prevented with a sizing agent to prevent water from entering.

  On the other hand, the adhesive layer 3b is used to join the display layer 3a and the detection layer 2 described above. An adhesive such as a pressure-sensitive adhesive (adhesive) or a heat-sensitive adhesive, or an epoxy-based adhesive is used. It is the layer which consists of. However, a cellulose-based adhesive having poor water resistance is not suitable.

  In addition, decoration, such as printing, is possible on the conditions that it does not contact | connect the detection layer which consists of a silicon oxide film on the base material 1. FIG. Similar to the display on the display layer 3a, an appropriate display format can be selected and adopted from geometric patterns, characters, symbols, photographs, paintings, illustrations, and the like. If the display layer 3a is transparent, the detection layer 2 is also transparent, so that a design combining the display layer 3a and the decoration applied to the substrate 1 is possible.

  Examples of the present invention will be described below.

A low-density polyethylene film with a thickness of 100 μm is printed with a water-based ink indicating “wet with water”, cut into a size of 15 mm × 30 mm, and a flat mold for injection molding of the same size. And insert molding together with high density polyethylene to form a 1 mm thick plate, which was used as a base material. And the silicon oxide film was formed into a detection layer by the plasma CVD method so that a carbon atom content rate might be 25% on the polyethylene film side of this base material, and it was set as the detection layer. On the other hand, a 40 μm polyethylene terephthalate (PET) film was back printed with “Caution”, and then a white solid layer was provided with a white ink on the back printed surface to form a release layer, which was then coated with a double-sided tape (adhesive layer). It fixed on the upper detection layer and the water-wetting detection sheet | seat of this invention concerning Example 1 was produced. The schematic configuration was as shown in FIG. When this detection sheet was observed from the release layer side, a “Warning Precaution” indication was seen. Next, when a wetness detection sheet was attached to a vertical surface and showered with water at a temperature of 20 ° C. for 30 seconds, the release layer was detached, and the display changed to “wet water”.

  A water wetness detection sheet of the present invention according to Example 2 was produced under the same conditions as in Example 1 except that the silicon oxide film constituting the detection layer was formed to have a carbon atom content of 12%. The schematic configuration was as shown in FIG. Next, when this water wetting detection sheet was attached to a vertical surface and showered with 20 ° C. water for 20 seconds, the release layer was detached and the display changed to “wet water”.

  A 15 mm × 30 mm low-density polyethylene film printed in reverse printing obtained in Example 1 is placed in the center of a flat plate mold 30 mm × 45 mm and formed into a base material. Carbon is formed on the entire surface of one surface. A silicon oxide film having an atomic content of 12% was formed as a detection layer. Subsequently, the release layer obtained in Example 1 was fixed on the detection layer with a double-sided tape (adhesive layer), and the water wetness detection sheet of the present invention according to Example 3 was produced. The schematic configuration was as shown in FIG. Next, when this was attached to a vertical surface and showered with 20 ° C. water for 10 seconds, the release layer peeled off and the display changed to “wet with water”.

  A substrate having a groove having a depth and width of 0.05 mm on the film surface is used as a substrate, and the water wetting detection sheet of the present invention according to Example 4 is used under the same conditions as in Example 3 except that. Produced. The schematic configuration was as shown in FIG. Next, when this is attached to a vertical surface and showered with 20 ° C. water, the wettability is improved by the capillary action of the groove provided, and the release layer comes off after 5 seconds of showering. The display switches to “Wet wet”.

  A high-density polyethylene is molded into a 1 mm thick plate using a flat mold for injection molding, and the surface is adjusted by corona treatment so that the surface tension is 70 dyne / cm with an indicator, and then a dye is dispersed in a cellulose resin. Was applied as a colorant and dried to prepare a water wetting detection sheet for comparison according to Example 5. Next, when this was affixed to the vertical surface and showered for 50 seconds with water at a temperature of 20 ° C., the coloring material gradually dissolved and water wetting could be confirmed.

It is explanatory drawing which shows the general | schematic cross-section structure of the water-wetting detection sheet | seat of this invention, and its use condition. It is explanatory drawing which shows the general | schematic cross-section structure of the other water-wetting detection sheet | seat of this invention, and its use condition. It is explanatory drawing which shows the general | schematic cross-section structure of the further another water-wetting detection sheet | seat of this invention, and its use condition. It is explanatory drawing which shows the general | schematic cross-section structure of the conventional water-wetting detection sheet | seat, and its use condition. It is explanatory drawing which shows the general | schematic cross-section structure of the other conventional water-wetting detection sheet | seat, and its use condition.

Explanation of symbols

1, 2, 31, 41, 51 .. Base material 2, 22, 32, .. detection layer 3, 23, 33 .. peeling layer 3a, 23a, 33a .. display layer 3b, 23b, 33b .. adhesive layer 4, 24, 34, 44, 54 .. Adherent adhesion layer 5, 25, 45, 35, 55 .. Adhering member 6 .. Groove 47, 57 .. Colored layers 48, 58.・ Water-soluble resin layer

Claims (4)

  A detection layer consisting of a silicon oxide film having a carbon atom content of 10% or more and less than 30% on a resin surface of a substrate having at least one surface made of resin, and dissolved by water wetting, along with dissolution of this detection layer A water wetness detection sheet, wherein a release layer that is peeled off at least is laminated.   2. The water wetting detection sheet according to claim 1, wherein the release layer is laminated on the detection layer in a state where a part of the detection layer is not covered, and a surface wetting angle is smaller than that of the substrate. .   3. The water according to claim 1, wherein the surface of the substrate that is in contact with the detection layer is provided with a water passage groove having a width of less than 0.1 mm for adjusting the dissolution rate of the detection layer. Wet detection sheet.   The water detection sheet according to claim 1, wherein the detection layer is formed by a plasma CVD method.