JP2008049487A - Decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet excellent in the adhesiveness and followability to an adherend, preventing the leaching of a pressure-adhesive agent to its surface and back through a gap even upon the reception of heavy load under a high temperature environment and simple in constitution. <P>SOLUTION: The decorative sheet 1 is constituted by laminating a punching sheet 2, a double-side pressure-sensitive adhesive sheet 3 and release paper 4 in this order. The pressure-sensitive adhesive sheet 3 comprises an acrylic polymer, a tackifier resin and an isocyanate crosslinking agent and 90-97 pts.mass of an alkyl (meth)acrylate monomer unit, 1-6 pts.mass of a carboxyl group-containing copolymerizable monomer unit and 0.05-0.3 pt.mass of a hydroxyl group-containing copolymerizable monomer unit are contained in 100 pts.mass of the polymer while the resin is contained in an amount of 20-35 pts.mass with respect to 100 pts.mass of the polymer, the crosslinking agent is contained in an amount of 0.8-3.0 pts.mass with respect to 100 pts.mass of the polymer and the resin. The thickness of the pressure-sensitive adhesive sheet 3 is 0.12-0.14 mm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a decorative sheet in which a pressure-sensitive adhesive does not ooze out to the front and back surfaces of a decorative sheet through a gap even when subjected to a heavy load in a high temperature environment.

  A technique for fixing an exterior material to an adherend via an adhesive is widely used as a technique for easily imparting desired design properties to the adherend. For example, perforated sheet materials such as punching sheets are widely used as exterior materials such as speakers for televisions and audio equipment, and various types of decorative sheets in which an adhesive layer is laminated on the exterior materials have been proposed. ing.

  These decorative sheets are generally manufactured in a form in which release paper is further laminated on the side opposite to the side where the exterior material of the pressure-sensitive adhesive layer is provided. Then, after being cut into a predetermined shape, in the manufacturing process of the adherend, the release paper is removed and affixed to the target portion of the adherend and fixed. At that time, if the release paper is provided with slits, a part of the release paper can be removed and temporarily fixed to the adherend, so that the decorative sheet can be fixed while easily and precisely aligning, further convenience. Will improve.

  On the other hand, the decorative sheet needs to have good adhesion and followability to the adherend, and further imparts design properties to the adherend, so that the decorative sheet itself has elements that impair the beauty. Don't be. However, especially when the exterior material is a porous sheet material, the appearance of the exterior material surface is likely to be impaired. For example, when the pressure-sensitive adhesive oozes out into the opening of the exterior material, the gloss caused by the pressure-sensitive adhesive comes to be visually recognized.

Further, when the decorative sheet is subjected to a heavy load in a high temperature environment, the adhesive may ooze out to the surface of the exterior material through the opening or may ooze out from the end face of the decorative sheet. As a result, the adhesive that has oozed out on the surface of the exterior material adheres and the aesthetic appearance is impaired.For example, if the decorative sheets are stacked and stored, the oozed adhesive will adhere the decorative sheets together. Sometimes it ends up.
Furthermore, when the release paper is provided with a slit, the adhesive may ooze out to the back of the decorative sheet through the slit under the same heavy load. In this case as well, for example, if the decorative sheets are stacked and stored, the oozed adhesive will adhere the decorative sheets to each other, and the beauty of the decorative sheet will be impaired.

On the other hand, for example, a porous sheet material, a thermally active adhesive layer, a support, an adhesive layer, and a release paper are laminated in this order as a decorative sheet in which the occurrence of gloss caused by the pressure-sensitive adhesive is prevented. A decorative sheet has been proposed (see Patent Documents 1 and 2).
Japanese Utility Model Publication No. 7-42287 JP-A-7-1265884

  However, the decorative sheets described in Patent Documents 1 and 2 have a problem that the configuration is complicated and cannot be manufactured at low cost. Further, although the occurrence of gloss due to the pressure-sensitive adhesive can be suppressed, it does not take into account the suppression of the pressure-sensitive adhesive oozing out on the front and back surfaces of the decorative sheet. And the present condition is that the structure is simple and the decorative sheet | seat in which the seepage of such an adhesive was suppressed was not proposed conventionally.

  The present invention has been made in view of the above circumstances, and is excellent in adhesion to and adherence to an adherend, and even when subjected to a heavy load under a high temperature environment, the pressure-sensitive adhesive is applied to the front and back surfaces of the decorative sheet through the gap. It is an object of the present invention to provide a decorative sheet having a simple configuration that does not ooze out.

As a result of intensive studies, the present inventors have found that such a problem can be solved by laminating a pressure-sensitive adhesive layer having a specific composition with a specific thickness, and have completed the present invention.
That is, the present invention is a decorative sheet obtained by laminating a punching sheet, a double-sided pressure-sensitive adhesive sheet, and a release paper in this order, and the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet contains an acrylic polymer, a tackifier resin, and a crosslinking agent. 90 parts by weight of a (meth) acrylic acid alkyl ester monomer unit having an alcohol residue having 4 to 14 carbon atoms and a carboxyl group-containing copolymer are formed from 100 parts by weight of the acrylic polymer. 1 to 6 parts by mass of a polymerizable monomer unit and 0.05 to 0.3 part by mass of a hydroxyl group-containing copolymerizable monomer unit are contained, and the tackifier resin is 20 to 35 parts per 100 parts by mass of the acrylic polymer. It is contained in parts by mass, and the crosslinking agent is an isocyanate-based crosslinking agent. 3.0 parts by weight is contained, the thickness of the double-sided pressure-sensitive adhesive sheet is a decorative sheet which is a 0.12～0.14Mm.

  According to the present invention, even when a heavy load is received in a high temperature environment, the adhesive in the double-sided pressure-sensitive adhesive sheet does not ooze out to the front and back surfaces of the decorative sheet through the gap, so that the beauty of the decorative sheet is impaired. There is nothing. In addition, since the adhesive does not ooze out, the decorative sheet is not damaged even when stacked and stored. In addition, a decorative sheet having excellent adhesion to the adherend and followability can be obtained. Furthermore, since the structure is simple, the decorative sheet can be manufactured at low cost.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In the present invention, (meth) acrylic acid refers to acrylic acid or methacrylic acid, and this also applies to acrylic acid or methacrylic acid derivatives.

(Decorative sheet)
The decorative sheet of the present invention is selected by selecting the optimum composition of the pressure-sensitive adhesive in the double-sided pressure-sensitive adhesive sheet, adjusting the degree of crosslinking of the acrylic polymer, and further adjusting the thickness of the double-sided pressure-sensitive adhesive sheet, The adhesion of the body and the followability are not impaired, and the leaching of the pressure-sensitive adhesive is suppressed.
FIG. 1 is a cross-sectional view showing an example of a decorative sheet according to the present invention. The decorative sheet 1 is formed by laminating a punching sheet 2, a double-sided pressure-sensitive adhesive sheet 3, and a release paper 4 in this order.

(Punching sheet)
The punching sheet 2 is not particularly limited as long as it is in the form of a sheet provided with a large number of fine through-holes 21, 21... Considering the followability to the body, cost, etc., it is preferably made of resin.
Specific examples of the resin in this case include polyester, polyvinyl chloride, and polystyrene, and polystyrene is preferable. These resins may contain conventionally known additives such as antioxidants or antistatic agents, if necessary.

  The through holes 21, 21... Of the punching sheet 2 are columnar, the diameter L is preferably 0.3 to 0.5 mm, and the aperture ratio is preferably 30 to 50%. When these conditions are satisfied, the effect of preventing the adhesive from seeping out from the through holes 21, 21... Can be further enhanced. In addition, although the cylindrical thing was taken up and demonstrated here as the through-holes 21, 21, ..., this invention is not limited to this.

(Double-sided adhesive sheet)
The double-sided pressure-sensitive adhesive sheet 3 has a double-sided pressure-sensitive adhesive tape structure having a fibrous support 33 as a core material. In the present invention, the present invention is not limited to this, and one having no fibrous support 33 can be used, but the double-sided pressure-sensitive adhesive tape structure is preferred.

When the thickness of the double-sided pressure-sensitive adhesive sheet exceeds 0.1 mm as in the present invention, when forming a double-sided pressure-sensitive adhesive sheet having a single layer structure in which a fibrous support is not provided by the method described later, In addition, the organic solvent tends to remain in the double-sided pressure-sensitive adhesive sheet, and bubbles or the like may be easily generated.
On the other hand, when forming a double-sided pressure-sensitive adhesive tape structure having a fibrous support as a core, as described later, the adhesive is thinner on both sides of the support than in the case of the single-layer structure. Since the layer is formed, the organic solvent hardly remains in the double-sided pressure-sensitive adhesive sheet, and bubbles and the like are hardly generated.

Specific examples of the fibrous support 33 include non-woven fabrics, and examples thereof include those made of materials such as pulp, cotton, hemp, and rayon. The basis weight of the fibrous support 33 is preferably 13 to 20 g / m ² . In addition, since the fibrous support 33 has low elasticity, even if it is provided in the double-sided pressure-sensitive adhesive sheet in this way, the followability, adhesion, etc. of the decorative sheet 1 to the adherend are not impaired.

  When the fibrous support 33 is thus provided, the thickness A of the first adhesive layer 31 on the punching sheet 2 side from the support 33 and the second on the release paper 4 side from the support 33 are provided. The ratio of the adhesive layer 32 to the thickness B is preferably A / B = 55/45 to 40/60, more preferably A / B = 50/50 to 40/60, and A / B. It is even more preferable that B = 48/52 to 40/60, and it is particularly preferable that A / B = 45/55. By setting it as such a ratio, the followable | trackability of the decorative sheet 1 to a to-be-adhered body becomes more favorable.

  Further, when the fibrous support 33 is provided, the composition of the first adhesive layer 31 and the second adhesive layer 32 is not necessarily the same, and the punching sheet to be used and the material of the adherend are used. You may select it in consideration. However, the same is preferable in that the manufacturing process can be simplified.

The pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet 3 is formed from a pressure-sensitive adhesive containing an acrylic polymer, a tackifier resin, and a crosslinking agent.
In 100 parts by mass of the acrylic polymer, 90 to 97 parts by mass of a (meth) acrylic acid alkyl ester monomer unit having an alcohol residue having 4 to 14 carbon atoms and a carboxyl group-containing copolymerizable monomer unit 1 to 6 parts by mass and 0.05 to 0.3 parts by mass of a hydroxyl group-containing copolymerizable monomer unit. In addition, the acrylic polymer may contain other monomer units such as vinyl acetate as long as the effects of the present invention are not impaired.

Specific examples of the (meth) acrylic acid alkyl ester having an alcohol residue having 4 to 14 carbon atoms include, for example, n-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, and cyclohexyl. Acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate , T-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, isooctyl Methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, isodecyl methacrylate, lauryl methacrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate.
Especially, the (meth) acrylic-acid alkylester which has a C4-C9 alcohol residue is preferable, and n-butyl acrylate is especially preferable.
In addition, in this invention, an alcohol residue refers to the site | part derived from the alcohol which forms the ester bond among (meth) acrylic-acid alkylesters.

  The carboxyl group-containing copolymerizable monomer is not particularly limited as long as it is copolymerizable with a (meth) acrylic acid alkyl ester having an alcohol residue having 4 to 14 carbon atoms. For example, (meth) acrylic acid , Acrylic acid dimer, itaconic acid, crotonic acid, maleic acid, maleic anhydride and the like. Of these, (meth) acrylic acid is particularly preferable.

  The hydroxyl group-containing copolymerizable monomer is not particularly limited as long as it is copolymerizable with a (meth) acrylic acid alkyl ester having an alcohol residue having 4 to 14 carbon atoms. For example, 2-hydroxyethyl (meta ) Acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and the like. Of these, 2-hydroxyethyl acrylate or 4-hydroxybutyl acrylate is preferable.

The (meth) acrylic acid alkyl ester having an alcohol residue having 4 to 14 carbon atoms is a base monomer. And the decorative sheet 1 becomes favorable in the followable | trackability to a to-be-adhered body by containing the said (meth) acrylic-acid alkylester.
On the other hand, the carboxyl group-containing copolymerizable monomer and the hydroxyl group-containing copolymerizable monomer are functional group monomers, and both adjust the degree of crosslinking of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet 3. The carboxyl group-containing copolymerizable monomer further adjusts the adhesiveness of the adhesive layer.

The tackifying resin is contained in an amount of 20 to 35 parts by mass with respect to 100 parts by mass of the double-sided PSA sheet.
Examples of tackifier resins include rosin resins such as rosin and rosin esterified products, terpene resins such as diterpene polymers and α-pinene-phenol copolymers, aliphatic (C5) and aromatic ( In addition, petroleum resins such as C9), styrenic resins, phenolic resins, xylene resins and the like are also included. Especially, what contains 75-85 mass parts of polymerized rosin and hydrogenated rosin, and 15-25 mass parts of petroleum resins in 100 mass parts of tackifying resin is preferable. Further, the polymerized rosin and the hydrogenated rosin are preferably contained in equal amounts. In 100 parts by mass of the tackifier resin, the polymerized rosin is 40 parts by mass, the hydrogenated rosin is 40 parts by mass, and the petroleum resin is 20 parts by mass. Partly contained is particularly preferred. Specific examples of the polymerized rosin include licarodine PCJ (trade name, manufactured by Rika Hercules Co., Ltd.). Specific examples of the hydrogenated rosin include Superester A100 (trade name, manufactured by Arakawa Chemical Industries, Ltd.). Specific examples of the petroleum resin include FTR-6100 (trade name, manufactured by Mitsui Chemicals, Inc.).
By using the tackifying resin having such a preferable composition, the degree of crosslinking of the adhesive layer of the double-sided pressure-sensitive adhesive sheet 3 is adjusted, the oozing of the pressure-sensitive adhesive is further suppressed, and the decorative sheet 1 follows the adherend. The property becomes better.

As said crosslinking agent, 0.8-3.0 mass parts of isocyanate type crosslinking agents are contained with respect to 100 mass parts of said acrylic polymers and tackifying resin.
And as an isocyanate type crosslinking agent, toluene diisocyanate adduct is preferable. Here, the toluene diisocyanate adduct refers to one containing a toluene diisocyanate derivative in the molecule. Specific examples include Coronate L (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.).
A crosslinking reaction advances because a crosslinking agent acts on the carboxyl group-containing copolymerizable monomer and hydroxyl group-containing copolymerizable monomer which are functional group monomers.

  In the decorative sheet of the present invention, the gel fraction, which is an index of the degree of crosslinking in the adhesive layer of the double-sided adhesive sheet, is about 45%. This is a little higher than the gel fraction of the conventional product, for example, about 35%. When the gel fraction is high, the double-sided PSA sheet generally tends to be hard, and when the double-sided PSA sheet is hardened and its thickness is reduced, the effect of suppressing the oozing out of the adhesive is enhanced. On the other hand, when the thickness of the double-sided pressure-sensitive adhesive sheet is increased, the followability of the double-sided pressure-sensitive adhesive sheet to the adherend tends to be improved. The decorative sheet of the present invention is configured to adjust the composition and thickness of the double-sided pressure-sensitive adhesive sheet so as to enhance the effect of suppressing the oozing of the pressure-sensitive adhesive without impairing the adhesion and followability to the adherend. Yes. The gel fraction is expressed as a percentage of the original mass by immersing the composition of the double-sided pressure-sensitive adhesive sheet after curing in toluene, measuring the mass after drying of the insoluble matter remaining after standing for 24 hours.

  In the double-sided PSA sheet, in addition to the components described above, various additives generally used in PSA, for example, antioxidants, UV absorbers, fillers, pigments, as long as the effects of the present invention are not impaired. Thickeners, plasticizers, softeners, flame retardants and the like may be contained.

  The pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet is, for example, 300 mm / min when folded 180 ° in the longitudinal direction from a state where it is laminated with a polystyrene punching sheet having a through-hole diameter of 0.35 mm, a hole area ratio of 42%, and a thickness of 0.4 mm. It is preferable that the adhesive force when it is pulled at a speed of and peeled off from the punching sheet is 16 (N / 20 mm) or more.

(Release paper)
In the present invention, conventionally known release papers can be used. For example, polyethylene laminated on any of high-quality paper, kraft paper, glassine paper, and kurpack paper, and a release treatment applied thereto, or synthetic resin films such as polyethylene, polypropylene, polyethylene terephthalate (PET) The thing etc. which performed the mold release process on the top are mentioned. Among these, from the viewpoint of productivity and pasting workability, it is preferable to laminate polyethylene on any of high-quality paper, kraft paper, glassine paper, and kurpack paper, and then perform release treatment thereon. Examples of the mold release treatment include conventionally known silicone treatment, long-chain alkyl treatment, fluorine treatment and the like, and silicone treatment is preferable.

The release paper 4 is provided with slits 41, 41. By providing the slits 41, 41, as described above, when fixing the decorative sheet 1 to the adherend, a part of the release paper is removed, and the decorative sheet 1 is temporarily fixed to the adherend. Thus, the decorative sheet 1 can be fixed to the adherend while performing simple and precise positioning. The number, shape, and size of the slits may be appropriately selected according to the purpose. And a slit should just be provided by a conventionally well-known method.
On the other hand, FIG. 1 shows a release paper provided with a slit, but the present invention is not limited to this, and a release paper provided with no slit may be used.

(Thickness of each layer)
In this invention, the thickness of the said double-sided adhesive sheet is 0.12-0.14 mm, and it is especially preferable that it is 0.125-0.135. And it is preferable that the thickness of the said punching sheet is 0.2-0.6 mm, and it is preferable that the thickness of the said release paper is 0.05-0.2 mm. By setting it as such a preferable range, the penetration of the adhesive from the punching sheet through-hole, release paper slit, and decorative sheet end face without impairing the adhesion and followability of the decorative sheet to the adherend The effect which suppresses can be heightened.

(Adherent)
In the decorative sheet of the present invention, the material of the adherend to be fixed is not particularly limited, but resins such as polystyrene, ABS, and polypropylene are suitable.

(Form of decorative sheet)
The form of the decorative sheet of the present invention is not particularly limited, and may be, for example, a sheet or roll product form.

(Manufacturing method of decorative sheet)
In order to form a double-sided PSA sheet, for example, a double-sided PSA sheet coating solution may be prepared and used for coating. Specifically, it is as follows.
That is, according to a conventionally known method, for example, an acrylic polymer is synthesized using a predetermined amount of a predetermined raw material monomer in an organic solvent. The organic solvent is not particularly limited as long as the compounding component to be used is dissolved and does not react with the functional group of the crosslinking agent. For example, ethyl acetate, toluene, xylene, n-hexane, acetone, methyl ethyl ketone Etc. can be used alone or in combination. Of these, ethyl acetate, n-hexane, acetone, and methyl ethyl ketone are preferable. Next, a predetermined amount of tackifying resin is added to the obtained acrylic polymer solution and mixed uniformly to obtain a pressure-sensitive adhesive solution. Furthermore, a coating solution for a double-sided pressure-sensitive adhesive sheet is obtained by adding a predetermined amount of a crosslinking agent to the obtained pressure-sensitive adhesive solution and stirring it. If necessary, the coating solution may be further diluted with an organic solvent such as toluene or hexane.

  When the double-sided pressure-sensitive adhesive sheet has a single-layer structure in which a fibrous support is not provided, specific examples of a method for producing a decorative sheet include the following methods. In other words, the coating solution is applied on the release treatment surface of the release paper using a roll coater or die coater so as to have a predetermined thickness after drying, and then is opposite to the release paper side. The method of sticking the adhesive layer surface of a side with a punching sheet can be mentioned. Alternatively, the coating solution is applied onto a temporary support and dried, and after the dried adhesive layer is transferred from the temporary support onto the punching sheet, the surface of the adhesive layer opposite to the punching sheet side is applied. A method of bonding to the release treatment surface of the release paper may be used.

  On the other hand, when the double-sided pressure-sensitive adhesive sheet has a double-sided pressure-sensitive adhesive tape structure having a fibrous support as a core, specific examples of the method for producing a decorative sheet include the following methods. That is, in order to impregnate the pressure-sensitive adhesive to the inside of the support, a coating solution for a double-sided pressure-sensitive adhesive sheet is directly applied to one side of the support, the organic solvent is dried, and the support impregnated with the pressure-sensitive adhesive to the inside. An adhesive layer having a predetermined thickness is formed on the body. Thereafter, an adhesive layer having a predetermined thickness separately formed on another temporary support is transferred from the temporary support to the surface on which the adhesive layer of the support is not formed, on both sides of the fibrous support. A double-sided adhesive sheet having a double-sided adhesive tape structure provided with an adhesive layer is formed. A method of transferring the double-sided pressure-sensitive adhesive sheet thus obtained onto a punching sheet can be mentioned.

  Alternatively, two sheets prepared by applying the coating solution onto a release paper and drying are prepared, and a double-sided adhesive layer in an impregnated state is provided on the support by laminating and bonding to both sides of the fibrous support, Next, a method of peeling the release paper on one side and bonding the release surface of the adhesive layer to the punching sheet may be used.

  Thus, in the case of forming a double-sided pressure-sensitive adhesive sheet having a double-sided pressure-sensitive adhesive tape structure, the pressure-sensitive adhesive layer used for drying is thinner than the case of forming the double-sided pressure-sensitive adhesive sheet having a single-layer structure described above. It is difficult for the organic solvent to remain in the layer, and bubbles are not easily generated. Therefore, a more uniform adhesive layer can be formed.

  As described above, the decorative sheet of the present invention is not only excellent in adhesion and followability to the adherend, but also when the adhesive is exposed to a heavy load under a high temperature environment, the adhesive is exposed to the surface of the decorative sheet through the gap. And it does not ooze out to the back. Therefore, for example, even when a large number of decorative sheets are stacked and stored in a high-temperature environment or when the decorative sheets are punched into a predetermined shape, the cosmetic sheets are not impaired in appearance and are not damaged. Moreover, since the structure is simple, it can be manufactured at low cost.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.
(Example 1)
Using the decorative sheet having the structure shown below, the adhesive was leached at the time of heat press and punching, and further the test was conducted on the resilience and adhesive force, and the test results were evaluated.
<Coating sheet>
(I) Double-sided pressure-sensitive adhesive tape In the double-sided pressure-sensitive adhesive sheet having the composition shown below, the nonwoven fabric having a basis weight of 17 g / m ² has a thickness (A) of the first pressure-sensitive adhesive layer on the punching sheet side from the nonwoven fabric, and the release paper side from the nonwoven fabric. A double-sided pressure-sensitive adhesive tape having a thickness of 0.135 mm, provided so that a ratio with the thickness (B) of the second pressure-sensitive adhesive layer is A / B = 45/55.
(I-1) Acrylic polymer As a monomer unit, 100 parts by mass of a resin monomer containing 93.4 parts by mass of butyl acrylate, 3 parts by mass of vinyl acetate, 3.5 parts by mass of acrylic acid and 0.1 parts by mass of hydroxyethyl acrylate .
(I-2) Tackifying resin With respect to 100 parts by mass of the resin monomer, Ricarodin PCJ (trade name, manufactured by Rika Hercules Co., Ltd.) 11.52 parts by mass, Superester A100 (trade name, manufactured by Arakawa Chemical Industries, Ltd.) 28.8 parts by mass of a tackifying resin containing 11.52 parts by mass and 5.76 parts by mass of FTR-6100 (trade name, manufactured by Mitsui Chemicals, Inc.).
(I-3) Crosslinking agent 1.5 parts by mass of Coronate L (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) with respect to 100 parts by mass of the resin monomer and the tackifier resin.
(I-4) Nonwoven fabric A nonwoven fabric with a basis weight of 17 g / m ² made of a mixed material of pulp, hemp, and rayon (manufactured by Nippon Daishowa Paperboard Co., Ltd.).
(II) Punching sheet A punching sheet made of polystyrene, a through hole diameter of 0.35 mm, a hole area ratio of 42%, and a thickness of 0.4 mm.
(III) Release paper A 0.13 mm-thick release paper (manufactured by Lintec Corporation) obtained by releasing a double-sided polyethylene laminate on a high-quality paper. However, in the heat press test, the one further provided with a slit having a width of 10 mm was used.

<Preparation of coating solution for double-sided PSA sheet>
The acrylic polymer was synthesized using a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet, and 0.1 parts by mass of perbutyl O (manufactured by NOF Corporation) as a polymerization initiator. Then, 200 parts by mass of ethyl acetate was added as a solvent, and solution polymerization was performed at 80 ° C. for 12 hours. Next, a tackifier resin was added to the obtained acrylic copolymer solution, dissolved by stirring, and toluene was further added to obtain a pressure-sensitive adhesive solution having a nonvolatile content of 40%. Next, a crosslinking agent was added and mixed well to obtain a coating solution for a double-sided PSA sheet.

<Manufacture of decorative sheets>
The decorative sheet was manufactured by the method shown below using the obtained coating solution for double-sided adhesive sheets. That is, the coating solution was coated on the release-treated surface of the release paper so that the thickness after drying was 61 μm, dried at 90 ° C. for 3 minutes to form an adhesive layer, and then laminated on one side of the nonwoven fabric did. Furthermore, the coating solution is applied on the release treatment surface of another release paper so that the thickness after drying becomes 74 μm, and dried at 90 ° C. for 3 minutes to form an adhesive layer, and then the other side of the nonwoven fabric It was bonded to the surface and heat laminated at 90 ° C. Thereafter, after heat treatment at 40 ° C. for 48 hours, the release paper having a thickness of 61 μm was peeled off, and the adhesive layer was bonded to the punching sheet.

<Test method>
The test method is as follows.
(1) Heat press Six of the decorative sheets cut to a size of 5 cm × 5 cm are stacked, and in a direction perpendicular to the decorative sheet surface, 6 hours at 40 ° C. or 2 hours at 60 ° C., 5 kg / cm ² Pressed with pressure. After completion of pressing, the decorative sheet was observed at a magnification of 200 times using an optical microscope, and the presence or absence of the adhesive leaching from the through-hole of the punching sheet and the slit of the release paper was evaluated.
(2) Punching The punching sheet side or release paper at 27 ° C. using a spring double blade with a blade height of 2 mm, a blade length of 6 mm, and a getter of 4 mm for the one decorative sheet cut to a size of 5 cm × 5 cm Punching by flat punching from the side was performed at a setting of 100 shots / minute. As the punching machine, a seal printing machine manufactured by Onda Manufacturing Co., Ltd. was used. The punched decorative sheet was observed at a magnification of 100 using an optical microscope, and the presence or absence of the adhesive leaching from the end face of the decorative sheet was evaluated.
(3) Resilience Release paper was peeled from the decorative sheet cut to a size of 20 mm × 180 mm, and fixed to the center of a polystyrene plate having a thickness of 2 mm, a width of 25 mm and a length of 200 mm. Next, the polystyrene plate on which the decorative sheet was fixed was fixed in a bow with a length of 190 mm along the longitudinal direction so that the decorative sheet was convex, and this state was maintained at 80 ° C. for 96 hours. Then, the presence or absence of peeling of the decorative sheet from the polystyrene plate after 96 hours was evaluated.
(4) Pst adhesive strength The decorative sheet is cut into a width of 20 mm, the release paper is peeled off, and the thickness of the adherend is applied by reciprocating the pressure of a 2 kg roller at 23 ° C. and a relative humidity of 50%. The sample was affixed to a 2 mm polystyrene (Pst) plate and left for 1 hour. Next, the decorative sheet was folded 180 ° in the longitudinal direction under the above conditions, pulled at a speed of 300 mm / min, and the adhesive strength (N / 20 mm) when peeled from the Pst plate was measured.

<Evaluation criteria>
The evaluation criteria of (1) heat press and (2) punching test results are as follows. The evaluation results are shown in Table 1.
◎ ・ ・ ・ No oozing out of adhesive, ◯ ・ ・ ・ No oozing out of adhesive and no problem in practical use, × ・ ・ ・ Estimated by oozing out of adhesive There are dirt and practical problems.
(3) The evaluation criteria for the resilience test results are as follows. The evaluation results are shown in Table 1.
○: no peeling from the polystyrene plate, x: peeling from the polystyrene plate.

(Examples 2-6, Comparative Examples 1-4)
Example 2 in the same manner as Example 1 except that the ratio A / B of the amount of the crosslinking agent in the double-sided PSA sheet, the total thickness of the double-sided PSA sheet, and the thickness of the PSA layer was as shown in Tables 1 and 2. -6, and manufacture and evaluation of the decorative sheet of Comparative Examples 1-4.

<Evaluation results>
(1) Heat press In Examples 1 to 6 and Comparative Examples 2 and 4, no leaching of the adhesive from the through hole of the punching sheet and the slit of the release paper was observed in any decorative sheet. On the other hand, in Comparative Examples 1 and 3, leaching of the adhesive from the through hole of the punching sheet and the slit of the release paper was observed in any decorative sheet.
(2) Punching In Examples 1 to 6 and Comparative Examples 2 and 4, no leaching of the adhesive from the through hole of the punching sheet and the slit of the release paper was observed in any decorative sheet. On the other hand, in Comparative Examples 1 and 3, leaching of the adhesive from the through hole of the punching sheet and the slit of the release paper was observed in any decorative sheet.
(3) Resilience In Examples 1 to 6 and Comparative Examples 1 and 3, peeling of the decorative sheet from the polystyrene plate was not recognized. On the other hand, in Comparative Examples 2 and 4, peeling of the punching sheet from the polystyrene plate was observed.
(4) Pst adhesive force It was confirmed that Examples 1-6 had a higher adhesive force than Comparative Examples 1-4.

  As described above, the pressure-sensitive adhesive used in the decorative sheet of the present invention is superior in adhesive strength to conventional pressure-sensitive adhesives, and has the double-sided pressure-sensitive adhesive tape having such a pressure-sensitive adhesive. It was confirmed that the sheet was superior to the conventional decorative sheet in terms of suppression of oozing of the adhesive and followability to the adherend.

  The present invention can be used as an exterior material for home appliances such as televisions and audio equipment, and is useful in the field of electrical appliances.

It is sectional drawing which shows an example of the decorative sheet which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cosmetic sheet, 2 ... Punching sheet, 3 ... Double-sided adhesive sheet, 4 ... Release paper, 31 ... 1st adhesive layer, 32 ... 2nd adhesive layer, 33 ... Fibrous support, 41 ... Slit

Claims (7)

A decorative sheet obtained by laminating a punching sheet, a double-sided adhesive sheet and a release paper in this order,
The pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet is formed from a pressure-sensitive adhesive containing an acrylic polymer, a tackifying resin and a crosslinking agent,
In 100 parts by mass of the acrylic polymer, 90 to 97 parts by mass of (meth) acrylic acid alkyl ester monomer units having an alcohol residue having 4 to 14 carbon atoms, and 1 carboxyl group-containing copolymerizable monomer unit. ~ 6 parts by mass and 0.05 to 0.3 parts by mass of a hydroxyl group-containing copolymerizable monomer unit,
The tackifying resin is contained in an amount of 20 to 35 parts by mass with respect to 100 parts by mass of the acrylic polymer,
The crosslinking agent is an isocyanate-based crosslinking agent, and is contained in an amount of 0.8 to 3.0 parts by mass with respect to 100 parts by mass of the acrylic polymer and the tackifying resin.
A decorative sheet, wherein the double-sided PSA sheet has a thickness of 0.12 to 0.14 mm.   The decorative sheet according to claim 1, wherein 75 to 85 parts by mass of polymerized rosin and hydrogenated rosin and 15 to 25 parts by mass of petroleum resin are contained in 100 parts by mass of the tackifying resin.   The decorative sheet according to claim 1 or 2, wherein the crosslinking agent is a toluene diisocyanate adduct.   The decorative sheet according to any one of claims 1 to 3, wherein the punching sheet has a thickness of 0.2 to 0.6 mm, and the release paper has a thickness of 0.05 to 0.2 mm.   The decorative sheet according to any one of claims 1 to 4, wherein a diameter of a through hole of the punching sheet is 0.3 to 0.5 mm, and an opening ratio is 30 to 50%.   The double-sided pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet having a nonwoven fabric as a core, and the ratio of the thickness (A) of the pressure-sensitive adhesive layer on the punching sheet side from the nonwoven fabric to the thickness (B) of the pressure-sensitive adhesive layer on the release paper side from the nonwoven fabric is A / B = 48/52 to 40/60. The decorative sheet according to any one of claims 1 to 5. The decorative sheet according to any one of claims 1 to 6, wherein the release paper is provided with a slit.

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