JP7618516B2 - Road marking sheet - Google Patents

Description

The present invention relates to a road marking sheet for drawing lines, letters, symbols, etc. on the road surface to clearly indicate road centerlines, pedestrian crossings, etc.

Various inventions have been disclosed regarding road marking sheets for marking road surfaces with lines, letters, etc. For example, in Patent Document 1, the applicant discloses a road marking sheet in which 100 parts by weight of an ethylene-vinyl acetate copolymer with a vinyl acetate content of 15-40% by weight and a melt index of 50-150 is mixed with 200-500 parts by weight of additives such as colorants, fillers, and reflective materials, which are then melt-mixed uniformly and formed into a sheet.

Furthermore, Patent Document 2 discloses a road surface marking material formed by laminating a hot melt adhesive on one surface of a substrate, the substrate having a softening point of 90°C or higher, and the hot melt adhesive having an elastic modulus of 10 ⁶ to 10 ¹⁰ Pa at 23°C and a softening point of 90°C or lower.

JP 2011-169048 A JP 2001-26915 A

Incidentally, the roads on which the road marking sheet of Patent Document 1 and the road surface marking material of Patent Document 2 are to be installed are generally assumed to be asphalt-paved roads. However, concrete surfaces can also be used as installation surfaces on which such road marking sheets are to be installed, and there has been a demand for a road marking sheet that can be used on installation surfaces with such different surface conditions.

The present invention aims to solve the problems mentioned above and provide a marking sheet that is easy to apply and has excellent adhesive properties regardless of the condition of the installation surface.

In order to solve the above problems, the inventors conducted extensive research and discovered that by making a marking sheet consisting of a base sheet containing a specific resin component and an adhesive layer whose main component is the specific resin component, the sheet has strong adhesive strength even on asphalt pavement and concrete surfaces, eliminating the need for pretreatment such as applying a primer to improve adhesion, which was previously necessary on some installation surfaces. This led to the completion of the present invention, which has led to the discovery that the sheet can be placed in a specified position on the installation surface and firmly adhered to the installation surface by heat treatment.

In order to achieve the above object, the present invention has the following configuration.
That is, the road marking sheet of the present invention is a road marking sheet that is heated to adhere to an installation surface, and comprises a base sheet having thermoplasticity that softens or melts when heated during application, and an adhesive layer arranged on the installation surface side of the base sheet, wherein the base sheet contains ethylene-vinyl acetate copolymer, the adhesive layer is mainly composed of polyamide or polyester, the porosity of the adhesive layer is 60 % or more , and the form of the adhesive layer is at least one of a sponge-like form or a nonwoven fabric form .

According to the present invention, a road marking sheet with excellent workability can be produced regardless of the condition of the installation surface.

1 is a front view showing an embodiment of a baseboard device according to the present invention; 2 is an enlarged cross-sectional view of line AA in FIG. 1;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described with reference to the drawings.
In the drawings, reference numeral 10 denotes a road marking sheet. The road marking sheet 10 shown in Fig. 1 is formed in a rectangular shape.

Figure 2 is a cross-sectional view taken along line A-A in Figure 1. The road marking sheet 10 is made up of two layers, a base sheet 20 and an adhesive layer 30 disposed on its underside. In this embodiment, the adhesive layer 30 is formed by applying an adhesive to the underside of the base sheet 20.

The road marking sheet 10 is placed on an installation surface such as a road surface with the bottom surface in contact, and is formed so that it softens or melts when heated from the top side, such as by burning with a flame, and adheres to the installation surface. Specifically, the base sheet 20 contains a binder as a raw material that softens or melts when heated and cools and hardens again when heating is stopped. In more detail, in addition to the binder, the base sheet 20 contains additives such as wax and pigments as raw materials, which are uniformly melted and mixed and formed into a sheet to provide the base sheet 20.

As the binder, ethylene-vinyl acetate copolymer, rosin, petroleum resin, etc. can be selected or combined, and the base sheet 20 in this embodiment contains ethylene-vinyl acetate copolymer as a binder in an amount of approximately 10 to 30% by weight of the total.

The base sheet 20 may be in the form of a long body of a fixed width, or in the form of a combination of multiple base sheets 20. In the latter case, specifically, a hole penetrating the thickness direction of a rectangular base sheet 20 is formed, and another base sheet 20 formed to match the outer diameter shape of the hole is fitted in to form an integral body. By making the outer diameter shape of the hole into a letter, number, or symbol, and changing the color tone of the other base sheet 20, it can also be used to provide information to passersby and passing vehicles. These base sheets 20 with different colors contain different pigments, but the other raw materials are almost the same.

The adhesive used in the adhesive layer 30 can be polyamide or polyester, which has a higher melting point or softening temperature than ethylene-vinyl acetate copolymer. In general, when applying the road marking sheet 10, the adhesive layer 30 side is placed on the application surface side, and the road marking sheet 10 is heated from the base sheet 20 side to melt it, and then cooled and solidified to adhere to the application surface. The application surface is usually assumed to be an asphalt pavement surface or a concrete surface. For example, when applying to an asphalt pavement surface, if the adhesive layer melts first when heated, the adhesive strength with the base sheet 20 side is not fully exerted, and part of the melted adhesive layer flows into the recess for asphalt, so that the adhesive strength between the base sheet 20 and the adhesive layer 30 may be partially reduced. Therefore, by using polyamide or polyester, which has a higher melting point or softening temperature than the ethylene-vinyl acetate copolymer contained in the base sheet 20, when the adhesive layer 30 is in a melted or softened state, the base sheet 20 is also melted or softened, so that the adhesive strength is fully exerted.

Considering the construction method of the road marking sheet 10 as described above, it is preferable that the thickness of the adhesive layer 30 is thin. This is because if the adhesive layer 30 is thick, when the road marking sheet 10 is heated during construction, heat rises from the top, and it takes time to fully heat the lower side of the adhesive layer 30 that is in contact with the construction surface. This means that insufficient heating time may result in insufficient adhesive strength of the adhesive layer 30 to the construction surface, or excessive heating time may result in thermal degradation such as discoloration of the base sheet 20.

One method for forming a thin adhesive layer 30 on the underside of the base sheet 20 is, for example, to simultaneously mold the adhesive layer 30 when forming the base sheet 20 by extrusion molding. However, while this method can be used when the base sheet 20 is in the form of a long body with a fixed width, it is difficult to use the above-mentioned method for a form in which multiple base sheets 20 are combined.

Therefore, in the present invention, the adhesive layer 30 is formed on the base sheet 20 afterwards. Specifically, there are two methods: a method of directly forming a thin sheet-like adhesive layer 30 on the underside of the base sheet 20 by spray painting, and a method of forming a sheet-like adhesive layer 30 and then placing it on the underside of the base sheet 20.

Examples of the form of the thin sheet-like adhesive layer 30 include one in which the adhesive is dissolved in a solvent to form a solution, or the adhesive is heated and melted, and the solution or molten material is spray-painted onto the underside of the base sheet 20 to form the adhesive layer 30.
When the adhesive is heated and melted, it is generally difficult to reduce the thickness of the adhesive layer 30. Therefore, it is preferable that the adhesive layer 30 has voids and is formed in a sponge-like shape with the voids communicating in the vertical and horizontal directions.

By forming a sponge-like adhesive layer 30 with voids, the amount of adhesive component (basis weight) per unit area can be reduced even if the thickness of the adhesive layer 30 per unit area is increased. Therefore, when the road marking sheet 10 is placed on the construction surface and heated, the base sheet 20 that melts first easily penetrates the voids in the sponge-like adhesive before it melts, so the adhesive layer 30 melts easily all the way down, and the adhesive strength at the interface between the base sheet 20 and the adhesive layer 30 can be expected to improve.

The latter sheet-like adhesive layer 30 can be formed by extrusion molding into a thin, elongated sheet, or by nonwoven fabric made of fibers of the adhesive component. When nonwoven fabric is used, the same effect as the sponge-like adhesive layer 30 described above can be expected.

When the above-mentioned adhesive layer 30 is in the form of a thin sheet, the construction surface, such as an asphalt pavement surface or concrete surface, is generally not always smooth, and therefore when the road marking sheet 10 is placed on the construction surface, gaps (air) exist between the construction surface and the adhesive layer 30. For this reason, the air may expand during heating, damaging parts of the road marking sheet 10 or leaving gaps remaining, which may prevent the adhesive strength from being fully exerted.
On the other hand, when a sponge-like adhesive layer 30 having voids or an adhesive layer 30 made of nonwoven fabric is used, even if gaps (air) are present, the air can move from the voids in the adhesive layer 30 along the side ends of the adhesive layer 30, and therefore, the remaining air can be discharged to the outside during the process of melting the adhesive layer 30 after heating, thereby making it possible to reduce gaps.

Next, an example of a road marking sheet 10 according to the present invention is shown.

Example 1
An adhesive layer 30 was formed by applying a dimer acid polyamide (manufactured by Bostec Co., Ltd., product name "HM4229") as an adhesive to the underside of a base sheet 20 (manufactured by Sekisui Plastics Co., Ltd., product name "Gisline S", width 150 mm) containing an ethylene-vinyl acetate copolymer.
Specifically, a solid of adhesive (polyamide) was placed in a container of a hot melt spray gun, and the inside of the container was heated to 180 to 210° C. to melt the polyamide, which was then applied to the bottom surface of the base sheet 20 with the bottom surface placed on the top surface to form a sponge-like adhesive layer 30. This was dried for 10 seconds to create a road marking sheet with the adhesive layer 30 solidified.

(Apparent specific gravity and porosity of adhesive layer)
The apparent specific gravity of the adhesive layer 30 was calculated in accordance with the fabric test method for woven and knitted fabrics (JIS L1096). Regarding the thickness of the adhesive layer 30, when the adhesive layer 30 can be peeled off from the base sheet 20, or when a separate adhesive layer 30 is used, the thickness of the peeled adhesive layer 30 was measured. When peeling from the base sheet 20 was difficult, the thickness of the adhesive layer 30 was determined by subtracting the thickness of the base sheet 20 from the thickness of the road marking sheet 10. In addition, when the adhesive layer 30 is formed by directly applying the adhesive to the application surface, the void ratio was considered to be 0%. In the road marking sheet 10 according to this embodiment, the adhesive layer 30 can be peeled off from the base sheet 20, and the void ratio (%) was calculated from the thickness (unit: μm), the specific gravity (g/cm3) of the adhesive component, the basis weight (g/m2), and the apparent density (g/cm3) of the peeled adhesive layer 30. The measurement results of each physical property value are shown in Table 1. The void ratio (%) was calculated based on the following calculation formula. Porosity (%) = (1-apparent specific gravity)/density x 100.

(Asphalt adhesion evaluation test)
The road marking sheet 10 prepared on the asphalt pavement surface was placed as the application surface, and the entire surface of the base sheet 20 was heated evenly from the upper side with a propane burner (nozzle diameter 100 mm, gas pressure 0.03 MPa, burner height 100 mm) to melt the road marking sheet 10, and cured for 1 hour. Next, in order to measure the adhesive strength using a Building Research Institute adhesion tester (Building Research Institute Tensile Tester, manufactured by Oxjack Co., Ltd., product name "LPT-1500"), a dedicated jig was bonded to the base sheet 20 with an adhesive (manufactured by Sekisui Plastics Co., Ltd., product name "Loadbond"), cured for 24 hours, and the strength of the force (kgf/cm ² ) when pulled upward with the Building Research Institute Tensile Tester was measured, and this was taken as the adhesive strength. The adhesiveness evaluation results are shown in Table 1.

(Concrete Adhesion Evaluation Test)
The adhesive strength to the concrete surface was measured by carrying out an adhesive strength evaluation test similar to that for the asphalt adhesive strength evaluation test. The adhesive strength measurement results are shown in Table 1.

As shown in Comparative Example 1 and Comparative Example 2 below, each adhesive was applied to an asphalt pavement surface and a concrete surface, and cured for 1 hour in Comparative Example 1 and 2 hours in Comparative Example 2 to allow it to dry sufficiently, forming an adhesive layer 30. Next, a base sheet 20 was placed on top of it, and the base sheet 20 was heated from the top side with a propane burner to melt the base sheet 20, and cured for 1 hour. After that, an adhesion evaluation test was conducted to measure the adhesive strength between the construction surface and the adhesive layer 30. Comparative Example 1 was used as the standard for the adhesive strength of the asphalt pavement surface, and Comparative Example 2 was used as the standard for the adhesive strength of the concrete surface, with each adhesive strength being set at 100, and the adhesive strength in each example and comparative example in Table 1 is listed as a relative value to the adhesive strength of Comparative Example 1 and Comparative Example 2.

Example 2
A road marking sheet 10 was obtained by laminating a polyester nonwoven fabric (manufactured by Kureha Tech Co., Ltd., product name "G4030") as an adhesive layer 30 onto a base sheet 20 (manufactured by Sekisui Plastics Co., Ltd., product name "Gisline S", width 150 mm) containing an ethylene-vinyl acetate copolymer.
The porosity of the adhesive layer 30 was calculated and an adhesion evaluation test for various application surfaces was carried out in the same manner as in Example 1. The physical property values and the results of the adhesion evaluation are shown in Table 1.

Example 3
A road marking sheet 10 was obtained in the same manner as in Example 2, except that a polyamide nonwoven fabric (manufactured by Kureha Tech Co., Ltd., product name "LSN0030") was used as the adhesive layer 30. As in Example 1, the porosity of the adhesive layer 30 was calculated and an adhesion evaluation test for various application surfaces was carried out. The physical property values and the adhesion evaluation results are shown in Table 1.

(Comparative Example 1)
In Example 1, a solvent-based adhesive containing chloroprene rubber as a main component (manufactured by Sekisui Plastics, product name "Gisline S Primer") was used instead of the adhesive. In each adhesion evaluation, instead of applying the adhesive to the base sheet 20, a solvent-based adhesive was applied to the asphalt pavement surface and cured for 1 hour to form an adhesive layer 30, and then the base sheet 20 was placed on top of the adhesive layer 30 and heated from the upper side of the base sheet 20 with a propane burner to melt the base sheet 20. After curing for 24 hours, an adhesion evaluation test for the asphalt pavement surface was carried out in the same manner as in Example 1. Note that, for the adhesive layer 30 according to this embodiment, a solvent-based adhesive was used and it was applied to the asphalt pavement surface, so the specific gravity, thickness, basis weight, apparent specific gravity, etc. were not measured, and the void ratio was set to 0% assuming that no voids were generated. The results of each adhesion evaluation are shown in Table 1.

(Comparative Example 2)
In Comparative Example 1, another solvent-based adhesive (manufactured by Sekisui Plastics, product name "Epo Primer C") mainly composed of epoxy resin was used. In each adhesion evaluation, instead of applying the adhesive to the base sheet 20, the solvent-based adhesive was applied to the concrete surface and cured for 1 hour to form the adhesive layer 30, and then the base sheet 20 was placed on top of it and heated from the upper side of the base sheet 20 with a propane burner to melt the base sheet 20. After curing for 24 hours, an adhesion evaluation test for the concrete surface was carried out in the same manner as in Example 1. Note that, for the adhesive layer 30 according to this embodiment, a solvent-based adhesive was used and it was applied to the concrete surface, so the specific gravity, thickness, basis weight, apparent specific gravity, etc. were not measured, and the void ratio was set to 0% assuming that no voids were generated. The results of each adhesion evaluation are shown in Table 1.

(Comparative Example 3)
A road marking sheet 10 was obtained in the same manner as in Example 1, except that an adhesive containing an ethylene-vinyl acetate copolymer (manufactured by Sanyo Life Materials Co., Ltd., product name "Puremelt P-502") was used as the adhesive to obtain a sponge-like adhesive layer 30. As in Example 1, the porosity of the adhesive layer 30 was calculated, and an adhesion evaluation test for various application surfaces was carried out. The physical property values and the adhesion evaluation results are shown in Table 1.

(Comparative Example 4)
In Example 1, a nylon-based polyamide (manufactured by Arkema, product name (Platamid HX2544)) was used as the adhesive, but the nozzle of the spray gun was clogged and the adhesive could not be applied to the base sheet 20. Therefore, it was not possible to evaluate each adhesive property.

(Comparative Example 5)
As the adhesive layer 30, a dimer acid polyamide (manufactured by Bostec, product name "HM4229") was pressed for 2 minutes with a hot press machine at 180 ° C. and molded into a sheet. The adhesive layer 30 was laminated on a base sheet 20 (manufactured by Sekisui Plastics, product name "Gisline S", width 150 mm) containing an ethylene-vinyl acetate copolymer to obtain a road marking sheet 10. Note that, for the adhesive layer 30 according to this embodiment, the void ratio was set to 0% assuming that no voids were generated. The adhesive layer 30 and the base sheet 20 were sequentially placed on an asphalt pavement surface as a construction surface, and the base sheet 20 was heated from the upper surface side with a propane burner to melt it, and cured for 24 hours. Subsequently, an adhesion evaluation test was performed to measure the adhesive strength to the construction surface. The adhesion evaluation results are shown in Table 1.

In Comparative Example 1 and Comparative Example 2, it takes 1 hour to cure the adhesive in Comparative Example 1, and 2 hours in Comparative Example 2. In other words, the adhesive application work and the construction work of the base sheet 20 are separated, but in Examples 1 to 3, the adhesive application work and the construction work of the base sheet 20 can be performed substantially simultaneously, resulting in excellent workability and excellent adhesive strength.

The reason why the adhesive strength of Examples 1 to 3 is higher than that of Comparative Example 1 and Comparative Example 2 is thought to be due to the difference in the shape of the adhesive layer 30. Specifically, when the road marking sheet 10 is applied, the heat is applied from the base sheet 20 side, so the base sheet 20 melts first and the adhesive layer 30 melts later. In Examples 1 to 3, the porosity of the adhesive layer 30 exceeds 50%, and the air in the adhesive layer 30 can move along the side ends of the adhesive layer 30, so the amount of air that can remain in the adhesive layer 30 can be reduced, and the impact on the adhesive strength can be reduced. In addition, since the melted base sheet 20 can penetrate into the voids, the contact area between the base sheet 20 and the adhesive layer 30 is increased, and the adhesive strength is thought to be increased. Furthermore, it is thought that the increased contact area between the base sheet 20 and the adhesive layer 30 makes it easier for the adhesive layer 30 to melt when heated, making it easier to express the adhesive strength to the application surface.

Comparing Example 1 and Comparative Example 5, the material of the adhesive layer 30 is the same, but the adhesive layer 30 is different in form, either a sponge-like form with voids or a thin sheet-like form without voids, and the adhesive strength to the asphalt pavement surface of Comparative Example 5 is 30% or more lower than that of Example 1. As mentioned above, when the adhesive layer 30 is in the form of a thin sheet, if gaps (air) occur between the application surface and the adhesive layer 30, it is difficult for the air to escape to the outside, and it is believed that this is why the adhesive strength is not fully expressed.

Comparative Example 3 uses the same resin component as the ethylene-vinyl acetate copolymer contained in the base sheet 20 as the main component of the adhesive in the adhesive layer 30, and has a sponge-like adhesive layer 30 with voids like Example 1, but the adhesive strength to the concrete surface is inferior to Examples 1 to 3 and Comparative Example 2.

10 Road marking sheet 20 Base sheet 30 Adhesive layer

Claims (1)

A road marking sheet that is heated and adheres to an installation surface,
A base sheet having thermoplasticity that softens or melts when heated during application;
An adhesive layer disposed on the installation surface side of the base sheet,
The base sheet contains an ethylene-vinyl acetate copolymer,
The adhesive layer is mainly composed of polyamide or polyester,
The adhesive layer has a porosity of 60 % or more,
The adhesive layer is in the form of at least one of a sponge and a nonwoven fabric.
A road marking sheet characterized by the above.

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