JP2010248430A - Pressure-sensitive adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet that suffers from neither blistering on pasting nor blistering after the lapse of time and leaves no pressure-sensitive adhesive agent on an adherend when peeled after pasted. <P>SOLUTION: The pressure-sensitive adhesive sheet comprises a substrate film and a pressure-sensitive adhesive layer and is manufactured by forming the pressure-sensitive adhesive layer on a release film and laminating the substrate film thereon, where the pressure-sensitive adhesive layer comprises regularly arranged pressure-sensitive adhesive convex portions formed on the pressure-sensitive adhesive surface; the pressure-sensitive adhesive convex portions have a convex shape with a curved surface smoothly swollen as the surface of a sphere; the thickness from the substrate film to the pressure-sensitive adhesive surface is 10-50 μm in the pressure-sensitive adhesive layer; the height of the pressure-sensitive adhesive convex portion on the pressure-sensitive adhesive surface is 3-10 μm; the pressure-sensitive adhesive convex portions are regularly arranged; and the pressure-sensitive adhesive sheet has a retention force of 0-1.0 mm as measured according to JIS Z-0237 for a polyvinyl chloride substrate film. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive sheet that easily escapes from the air.

  When the pressure-sensitive adhesive sheet is pasted on the object to be pasted, a squeegee or the like as an affixing tool is pressed against the surface of the pressure-sensitive adhesive sheet and is pasted on the object to be pasted so as to remove air. If the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet is flat, even if a squeegee or the like as a sticking tool is used, it is difficult to remove air well, resulting in a “bulge” of the remaining air.

  In view of this, an adhesive sheet having a path on which unevenness is provided on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet has been developed. For example, there are JP-A-59-078285, utility model registration No. 2503717, and JP-A-2004-075843.

JP 59-0778285 Utility Model Registration No. 2503717 JP 2004-075843 A

  In these developed pressure-sensitive adhesive sheets, the air is not completely removed by pressing the squeegee only once, and the surface of the pressure-sensitive adhesive sheet may be somewhat “bulged”. In this case, the squeegee was pressed several times to evacuate the air to eliminate the “bulge”. There was a need to press the squeegee many times and remove the air without pressing the squeegee once to eliminate the “bulge” when sticking.

  Also, after pasting without the “bulge”, the “bulge” sometimes occurred after a while. Since there is no “bulge” after this time has passed, some gas that is so small that it cannot be seen will come out of the adhesive sheet or object to be collected over time and will be visible. It has become a “bulge”. Examples of the gas that is so small as to be invisible include those left behind at the time of pasting and those in which a residual solvent such as an adhesive layer is volatilized. It was required that “bulge” would not occur even if gas emerged over time.

  In addition, there is a use application to reattach the adhesive sheet, and when the adhesive sheet is peeled off after a while after being attached to the object, even if there are uneven paths on the adhesive surface, it will be torn off at the convex part and covered. It was also required that no adhesive remain on the patch.

  The problem to be solved by the present invention is that “swelling” does not occur when pasting, and “swelling” does not occur after a long time. It is to provide an adhesive sheet in which no adhesive remains.

  In order to solve these problems, the present inventors have found that the relationship between the shape of the adhesive convex portion, the regular arrangement, and the holding force of the adhesive sheet is important. Due to these relationships, even if a squeegee or the like is pressed against the path, the path does not collapse, and even after a long time, due to the shape and regular arrangement of the adhesive convex parts, gas does not easily escape and swell does not occur. When the pressure-sensitive adhesive sheet was peeled off, the pressure-sensitive adhesive could not be left on the adherend.

  The present invention relates to a pressure-sensitive adhesive sheet comprising a base film and a pressure-sensitive adhesive layer, which is produced by forming a pressure-sensitive adhesive layer on a mold release film and bonding the base film, and the mold release film is provided with concave portions having a regular arrangement. The pressure-sensitive adhesive layer is formed by coating the mold release surface, and the pressure-sensitive adhesive convex portions are formed by regularly arranging the pressure-sensitive adhesive convex portions on the pressure-sensitive adhesive surface. Is a curved convex shape that swells smoothly like a sphere surface, the thickness from the base film to the adhesive surface in the adhesive layer is 10 μm to 50 μm, and the height of the adhesive convex portion on the adhesive surface is 3 μm The regular arrangement is that the boundary surface shape between the adhesive surface and the adhesive convex portion is a circle or a regular polygon, and the center or center of gravity of the same rhombus is not a square that repeats sharing a side. Is the length of one side of the rhombus Polyvinyl chloride with a radius from the center of the boundary surface circle or a length from the center of gravity of the boundary surface regular polygon to the vertex of the regular polygon from 0.3 mm to 0.9 mm The holding force measured according to JIS Z-0237 is 0 to 1.0 mm.

  According to the present invention, “swelling” does not occur when pasting, “swelling” after time does not occur, and no adhesive remains on the adherend when the adhesive sheet is peeled off after pasting The adhesive sheet can be provided.

It is explanatory drawing which showed the cross section at the time of adhesive sheet manufacture. It is explanatory drawing which showed the cross section of the adhesive sheet. It is explanatory drawing which expanded the adhesion convex part. It is explanatory drawing which showed the boundary surface of an adhesive surface and an adhesive convex part. It is explanatory drawing of regular arrangement | positioning. It is explanatory drawing which showed the state before a squeegee. It is explanatory drawing which showed the state after a squeegee. It is explanatory drawing which showed the state which passed for one month. It is explanatory drawing of arrangement | positioning located in the vertex of a square.

  FIG. 1 is an explanatory view showing a cross section when the pressure-sensitive adhesive sheet 1 is manufactured. The release film 2 has a release surface 6 in which concave portions with regular arrangement are provided by embossing. The pressure-sensitive adhesive layer 3 is formed by coating on the release surface 6, and the pressure-sensitive adhesive convex portions 5 having a regular arrangement are formed on the pressure-sensitive adhesive surface. Next, the base film 4 is bonded together, and the adhesive sheet 1 is manufactured.

  The release film 2 may be any material that can be provided with a concave portion by embossing. However, time passes until it is applied after embossing, or it moves to be applied at a place different from embossing. In this case, PET (polyethylene terephthalate) and PP (polypropylene) are preferable because the shape of the concave portion is stable.

  Here, the coating is a layer formed by applying an adhesive layer coating solution using a so-called coater such as a blade coater, bar coater, comma coater, reverse roll coater, or gravure coater. The adhesive layer 3 is formed by ultraviolet curing or the like. When the coating liquid is liquid, the pressure-sensitive adhesive layer 3 having the pressure-sensitive adhesive convex portions 5 on the pressure-sensitive adhesive surface can be formed.

  As the adhesive layer coating liquid, an acrylic or vinyl ether synthetic resin or rubber-based material that is generally handled as an adhesive can be used. It is preferable to use a crosslinking agent or a curing agent in combination because the shape of the adhesive convex portion 5 can be manufactured stably. If necessary, you may mix | blend a filler, an adhesive property modifier, an anti-aging agent, etc.

  As the base film 4, a film according to the intended use of the pressure-sensitive adhesive sheet 1 is used. For example, for applications such as image posters, a pre-printed image, a polyvinyl chloride film that can be printed after the pressure-sensitive adhesive sheet 1 is formed, or PET (polyethylene terephthalate) having a print receiving layer formed on the surface 15 Film or synthetic paper is used. In this case, printing is often performed by an inkjet printer. As ink for an ink jet printer, solvent-based ink, water-based ink, ultraviolet curable ink, or the like is used. The combination of ink jets depends on the place of use. In addition, a film having a functional layer formed on the surface 15 may be used.

  FIG. 2 is an explanatory view showing a cross section of the pressure-sensitive adhesive sheet 1. 2 is peeled off from the release film 2 of FIG. 1, and the top and bottom of FIG. 1 are reversed. The base film 4 has an adhesive layer 3, and the adhesive layer 3 is a part including the adhesive convex part 5. The adhesive convex portions 5 are formed on the adhesive surface 7 in a regular arrangement. The adhesive convex portion 5 has a curved convex shape that swells smoothly like a spherical surface. In the figure, the adhesive convex portion 5 is enlarged and expressed in the vertical direction of the drawing, and thus has a hemispherical shape.

  The thickness p from the base film 4 to the adhesive surface 7 in the adhesive layer 3 is 10 μm to 50 μm, and the height t of the adhesive convex portion 5 on the adhesive surface 7 is 3 μm to 10 μm. These are the adhesive layer 3.

  If the thickness p from the base film 4 to the pressure-sensitive adhesive surface 7 in the pressure-sensitive adhesive layer 3 is smaller than 10 μm, the pressure-sensitive adhesive sheet 1 is easily peeled off, or if the thickness p is larger than 50 μm, the pressure-sensitive adhesive sheet 1 is covered when the pressure-sensitive adhesive sheet 1 is attached. The adhesive may remain on the patch.

  If the height t of the adhesive convex portion 5 on the adhesive surface 7 is smaller than 3 μm, the air cannot be removed even by pressing a squeegee or the like, and “swelling” occurs or it is pasted if it is larger than 10 μm. When the pressure-sensitive adhesive sheet 1 is peeled off, there may be a problem that the pressure-sensitive adhesive remains on the adherend.

  FIG. 3 is an explanatory view showing a cross section of the adhesive convex portion 5. It is assumed that the boundary surface shape between the adhesive surface 7 and the adhesive convex portion 5 is circular. A perpendicular line LN on the circular center N and a circular diameter KM (radius r) are indicated by a one-dot broken line. As described above, the height t of the adhesive convex portion 5 on the adhesive surface 7 is 3 μm to 10 μm.

  The adhesive convex portion 5 does not have a step like a staircase, and has a curved convex shape that swells smoothly like a spherical surface as shown in the figure. If there is a step such as a staircase, air may remain on the step when sticking. When the curved surface swells smoothly like the surface of a sphere, air is pushed out by the curved surface that swells smoothly when affixed, and air hardly remains.

  The radius r from the center of the boundary surface circle (or the length r from the center of gravity of the boundary surface regular polygon to the vertex of the regular polygon) is 0.1 mm to 0.3 mm. From the relationship between the height t of the pressure-sensitive adhesive convex portion 5 on the pressure-sensitive adhesive surface 7 and the holding force of the pressure-sensitive adhesive sheet 1, the radius r or the length r is in this range.

  If the radius r from the center of the boundary surface circle or the length r from the center of gravity of the boundary surface regular polygon to the vertex of the regular polygon is smaller than 0.1 mm, the pressure-sensitive adhesive sheet 1 is easily peeled off or from 0.3 mm If it is large, even if it is a convex shape of a curved surface that swells smoothly like the surface of a sphere, there may be a problem that air remains when affixing.

  FIG. 4 is an explanatory view showing a boundary surface 8 between the adhesive surface and the adhesive convex portion. FIG. 3 is a cross section taken along the line A-A ′ in FIG. In this case, the shape of the boundary surface 8 between the adhesive surface and the adhesive convex portion is circular. FIG. 2 shows a B-B ′ cross section of FIG. 4.

  The shape of the boundary surface 8 is not limited to a circle but may be a regular polygon including a star-shaped regular polygon. Since it is circular or regular polygonal and has a convex shape of a curved surface that swells smoothly like the surface of a sphere, air is easily left without leaving. Even a regular polygon, a regular polygon having more corners than a regular hexagon is preferable because it is closer to a circle.

  FIG. 5 is an explanatory diagram of regular arrangement. FIG. 5A shows the same rhombus 9 that is not square and repeats while sharing the side 10. In FIG. 5B, the center N of the circular boundary surface between the adhesive surface and the adhesive convex portion is located at the apex 11 of the rhombus 9. In FIG. 5C, the rhombus 9 is deleted so that only the boundary surface 8 circular between the adhesive surface and the adhesive convex portion is formed, which is the same as FIG. When the shape of the boundary surface 8 is not a circle but a regular polygon, the center of gravity N of the boundary surface regular polygon is located at the vertex 11 of the same rhombus 9 that is not a square that repeats sharing the side 10.

  The length of one side 10 of the rhombus is 0.3 mm to 0.9 mm, and the radius r from the center of the boundary surface circle or the length r from the center of gravity of the boundary surface regular polygon to the vertex of the regular polygon is 0.1 mm. ~ 0.3 mm. In addition, at the time of manufacture of an adhesive sheet, the boundary surface shape between the adhesive surface and the adhesive convex portion is a circle or a regular polygon, and adjacent boundary surface shapes are not in contact with or connected to each other. If it is in contact or connected, air tends to remain, which is not preferable.

  If the length of one side of the rhombus is smaller than 0.3 mm, the gas may not escape, and if it is larger than 0.9 mm, the adhesive sheet may be easily peeled off.

  Thus, the pressure-sensitive adhesive layer is formed by coating the release film on the release surface, and regularly arranged pressure-sensitive adhesive convex portions are formed on the pressure-sensitive adhesive surface. It is a curved convex shape that swells smoothly like the surface, the thickness from the base film to the adhesive surface in the adhesive layer is 10 μm to 50 μm, and the height of the adhesive convex portion on the adhesive surface is 3 μm to 10 μm Yes, the regular arrangement is such that the boundary surface shape between the adhesive surface and the adhesive convex part is a circle or regular polygon, and the center or center of gravity is located at the apex of the same rhombus that is not a square that repeats sharing sides. The length of one side of the rhombus is 0.3 mm to 0.9 mm, and the length from the center of the boundary circle or the center of gravity of the boundary regular polygon to the vertex of the regular polygon Is 0.1 mm to 0.3 mm.

  FIG. 6 is an explanatory view showing a state before the squeegee in which the adhesive sheet 1 is attached to the object to be attached 12. FIG. 6A shows a state before the adhesive film 1 is peeled off from the release film and the pressure-sensitive adhesive sheet 1 is stuck on the object to be stuck 12, and before the squeegee is pressed. FIG. 6B is a C-C ′ cross section of FIG. 6A, and the contact surface 13 between the adherend 12 and the adhesive convex portion 5 is indicated by oblique lines. FIG. 6A shows the D-D ′ cross section of FIG.

  As shown in FIG. 6, even in the state before the pasted squeegee, the path 14 through which the air escapes already exists, so that even in this state, “bulging” due to the remaining air is already difficult to occur.

  FIG. 7 is an explanatory view showing a state after the squeegee in which the pressure-sensitive adhesive sheet 1 is attached to the article 12. FIG. 7A shows a state in which the pressure-sensitive adhesive sheet 1 is attached to the object to be attached 12 and a squeegee is pressed to attach air so as to remove air. FIG. 7B is an E-E ′ cross section of FIG. 7A, and the contact surface 13 between the adherend 12 and the adhesive convex portion 5 is indicated by hatching. Although the area is slightly larger than the contact surface 13 between the adherend 12 and the adhesive convex portion 5 in FIG. 6 (b), the path 14 through which the air escapes does not change significantly and is slightly reduced. It is a degree. FIG. 7A shows the E-E ′ cross section of FIG.

  In order to obtain the state as shown in FIG. 6 or FIG. 7, any polyvinyl chloride base film having a holding force of 0 to 1.0 mm measured according to JIS Z-0237 may be used. The holding force is more preferably 0 to 0.5 mm, and further preferably 0 mm. In addition, with such a holding force, the adhesive does not remain on the adherend when the adhesive sheet is peeled off. If the value of the holding force is large, the adhesive convex portion may be crushed when the squeegee is pressed, or a “bulge” may occur after a while.

  Using a PET (polyethylene terephthalate) film having a thickness of 50 μm as a release film, concave portions with regular arrangement were provided by embossing. The adhesive coating solution is applied to the release surface provided with the concave portions with the regular arrangement, and is heated and dried. The thickness of the adhesive layer from the base film to the adhesive surface is 25 μm. An adhesive layer having a convex portion height of 8 μm was formed. The regular arrangement is such that the boundary surface shape between the adhesive surface and the adhesive convex portion is circular, and the center thereof is located at the apex of the same rhombus that is not a square that repeats sharing a side. The length of the side is 0.47 mm, and the radius from the center of the boundary surface circle is 0.16 mm. Using a polyvinyl chloride film having a thickness of 80 μm as a base film, it was bonded onto the adhesive layer to produce an adhesive sheet.

  The adhesive coating solution was 99% by weight of SK Dyne 1442 manufactured by Soken Chemical Co., Ltd., which is an acrylic adhesive, and 0.1% by weight of L-45 manufactured by Soken Chemical Co., Ltd., which is an isocyanate-based cross-linking agent. A mixture of E-5XM manufactured by Soken Chemical Co., Ltd., which is an epoxy crosslinking agent, in a toluene solution so as to be 0.9% by weight was used. In addition, you may color by mixing a coloring agent with this.

  The pressure-sensitive adhesive sheet produced in this way was measured for holding power according to JIS Z-0237 and found to be 0 mm. Moreover, when each holding power was measured 24 hours after and 48 hours after sticking, both were 0 mm.

  In addition, using a transparent glass plate and a transparent acrylic plate as the article to be pasted, the adhesive sheet 1 was pasted, and the state before and after the squeegee was observed from the transparent glass plate and acrylic plate side, These are the same as FIG. 6B and FIG. 7B, respectively.

  Further, FIG. 8 is an explanatory view showing a state in which one month has passed after the adhesive sheet is attached to the object to be attached. FIG. 8A shows a state in which one month has passed after the adhesive sheet 1 is applied to the object to be attached 12 by pressing the squeegee so as to remove air. FIG. 8B is a G-G ′ cross section of FIG. 8A, and the contact surface 13 between the adherend 12 and the adhesive convex portion 5 is indicated by oblique lines. FIG. 8A shows the H-H ′ cross section of FIG.

  In addition, what adhered the adhesive sheet 1 using the transparent glass plate and the transparent acrylic board as the to-be-attached object 12, and observed the state which passed for one month from the transparent glass board and the acrylic board side is FIG. Same as (b).

  Even in a state where one month has passed in this way, all the paths 14 through which air escapes are not lost, and a little remains, and even if gas comes out with the passage of time, gas does not escape through this path 14 and collect. No “bulge” occurs.

  It is a regular arrangement in which the boundary surface shape between the adhesive surface and the adhesive convex portion is a circle or regular polygon, and the center or center of gravity is located at the apex of the same rhombus that is not a square that repeats sharing sides Therefore, such a route 14 can be formed. If the vertices are arranged at the same interval like a square, not a rhombus that is not a square, a path as shown in FIG.

  FIG. 9 is an explanatory diagram of an arrangement located at a vertex of a square. The boundary surface shape between the adhesive surface and the adhesive convex portion is a circle, and the center thereof is located at the apex of the square. The contact surface 13 between the object to be pasted and the adhesive convex portion is indicated by hatching. Over time, adjacent adhesive convex portions are connected. Unlike FIG. 8, a path cannot be formed, and a gap 16 is formed. In such a state, gas does not escape and the air gap 16 becomes a “bulge”. In order to avoid this, it is necessary to make a regular arrangement located at the apex of the same rhombus that is not square.

  In addition, when the adhesive sheet 1 is pasted using a transparent glass plate and a transparent acrylic plate as the article to be pasted and passed for 48 hours at 50 ° C., the path 14 cannot be observed at all, and the temperature is returned to room temperature. Even if left unattended, the route 14 was not revived and “bulging” did not occur. Most of the gas from the adhesive sheet was released.

  As an actual construction, an image was printed on a 900 mm × 1800 mm pressure-sensitive adhesive sheet (polyvinyl chloride side) with a solvent-based ink-jet printer, and a squeegee was pressed on the adhesive sheet to be attached to an object. Without causing “bulge”, the squeegee could be pressed once to eliminate “bulge”. After that, after 1 week and 1 month were observed, no new “bulge” occurred. Moreover, the adhesive did not remain on the object to be pasted when the adhesive sheet after one month was peeled off.

  Similarly to Example 1, a release film was used to form an adhesive layer having a thickness from the base film to the adhesive surface of the adhesive layer of 25 μm and the height of the adhesive convex portion on the adhesive surface of 8 μm. The regular arrangement is such that the boundary surface shape between the adhesive surface and the adhesive convex portion is circular, and the center thereof is located at the apex of the same rhombus that is not a square that repeats sharing a side. The length of the side is 0.47 mm, and the radius from the center of the boundary surface circle is 0.16 mm. An adhesive sheet was produced by laminating on a pressure-sensitive adhesive layer using a substrate film having a 30-μm thick ink jet receiving layer formed on a PET film having a thickness of 100 μm.

  Except for this base film, Example 2 is the same as Example 1. Therefore, the holding force measured according to JIS Z-0237 on the polyvinyl chloride base film in Example 2 was the same as that in Example 1 and was 0 mm. Moreover, when each holding power was measured 24 hours after and 48 hours after sticking, both were 0 mm.

  The inkjet receptive layer on the PET film as the substrate film was formed by applying an inkjet receptive layer coating solution with a reverse roll coater and heating and drying. The inkjet receptive layer coating liquid is composed of the following raw materials and weight%, and these are prepared by stirring with ion exchange water. 72% by weight of polyether-based urethane resin (Daiichi Kogyo Seiyaku Co., Ltd. Superflex 600 solids 25%) and 24% by weight of acrylic / styrene copolymer resin (Chuo Rika Kogyo Co., Ltd. Rikabond FK-820 solids 39%) , 0.5% by weight of a water-soluble polymer having an oxazoline group (solid content 40%), and a hydrogen chloride neutralized product (solid) of a grafted product of methacrylic acid / butyl acrylate / methyl methacrylate / styrene copolymer and polyethyleneimine 49%) and 3.5% by weight. This is the same as that described in Example 1 of Japanese Patent No. 4127531.

  In addition, the adhesive sheet 1 of Example 2 was affixed using a transparent glass plate and a transparent acrylic plate as the adherend 12, and the state before and after the squeegee was observed from the transparent glass plate and acrylic plate side. Similar to the first embodiment, these are the same as in FIG. 6B and FIG. 7B, respectively. Moreover, what adhered the adhesive sheet 1 of Example 2 and observed the state which passed for one month from the transparent glass plate and the acrylic board side is also the same as FIG. .

  As an actual construction of Example 2, an image is printed on a 900 mm × 1800 mm pressure-sensitive adhesive sheet (inkjet receiving layer side) with a solvent-based ink inkjet printer, and a squeegee is pressed on the adhesive sheet to be applied to an object. went. Without causing “bulge”, the squeegee could be pressed once to eliminate “bulge”. After that, after 1 week and 1 month were observed, no new “bulge” occurred. Moreover, the adhesive did not remain on the object to be pasted when the adhesive sheet after one month was peeled off.

DESCRIPTION OF SYMBOLS 1 Adhesive sheet 2 Release film 3 Adhesive layer 4 Base film 5 Adhesive convex part 6 Release surface 7 Adhesive surface 8 Boundary surface 9 Rhombus 10 Side of rhombus 11 Vertex of rhombus 12 Sticking object 13 Contact surface 14 Path | route 15 Surface 16 Gaps N Center of boundary circle or center of boundary regular polygon p Thickness from base film to adhesive surface t Height of adhesive convex part on adhesive surface r Radius or length from center of gravity to vertex

Claims (1)

  In a pressure-sensitive adhesive sheet comprising a base film and a pressure-sensitive adhesive layer, which is produced by forming a pressure-sensitive adhesive layer on the mold release film and bonding the base film, the release film is provided with a regularly arranged concave portion. The pressure-sensitive adhesive layer is formed by coating on the release surface, and the pressure-sensitive adhesive convex portions are regularly formed on the pressure-sensitive adhesive surface. Is a curved convex shape that swells smoothly, the thickness of the adhesive layer from the base film to the adhesive surface is 10 μm to 50 μm, and the height of the adhesive convex portion on the adhesive surface is 3 μm to 10 μm The regular arrangement is such that the boundary surface shape between the adhesive surface and the adhesive convex portion is a circle or regular polygon, and its center or center of gravity is located at the apex of the same rhombus that is not a square that shares a side. The length of one side of the rhombus is 0.3m -0.9 mm, the radius from the center of the boundary surface circle or the length from the center of gravity of the boundary surface regular polygon to the vertex of the regular polygon is 0.1 mm to 0.3 mm; A pressure-sensitive adhesive sheet characterized by having a holding force of 0 to 1.0 mm measured according to JIS Z-0237 using a film.

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