Adhesive sheets and printed matter

Abstract

To provide an adhesive sheet that is excellent in weather resistance and the like and is suitable for inkjet printing, and provide a printed material that is excellent in weather resistance and the like and has a printed part of high print quality, with less smearing due to inkjet printing.SOLUTION: The inventive adhesive sheet is used in inkjet printing. The adhesive sheet has a substrate composed of materials containing polyvinyl chloride and a cellulose derivative. The cellulose derivative is preferably at least one of cellulose acetate propionate and cellulose acetate butylate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pressure-sensitive adhesive sheet and a printed matter. [Background technology]

[0002] 2. Description of the Related Art Polyvinyl chloride sheets have been widely used as decorative pressure-sensitive adhesive sheets for advertisements, signs, and the like, due to their excellent weather resistance and ability to conform to curved or uneven surfaces.

[0003] In applications such as advertising and signboards, replacement is often required at relatively short intervals, and small lot production is sometimes required.

[0004] On the other hand, printing by the inkjet method has the characteristics of being excellent in on-demand printing and being suitable for producing a large number of printed items in small quantities.

[0005] The inkjet method is also increasingly being applied to printing on decorative adhesive sheets.

[0006] However, when conventional polyvinyl chloride is printed on by the inkjet method, there is a problem that the print by the inkjet method tends to be unclear.

[0007] In order to solve the above-mentioned problems that occur when printing by the inkjet method, a sheet material provided with an ink-receiving layer made of a specific material has been proposed (see, for example, Patent Document 1).

[0008] However, even such sheet materials could not be made to have sufficiently excellent printability by the ink-jet method. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 3745993 Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide an adhesive sheet which is excellent in weather resistance, etc. and in addition has excellent printability by the inkjet method, and to provide a printed matter which is excellent in weather resistance, etc. and has a printed part with excellent print quality with little bleeding, etc. by the inkjet method. [Means for solving the problem]

[0011] Such objectives are as follows: 3 This is achieved by the present invention described in (1) An adhesive sheet used for printing by an inkjet method, Polyvinyl chloride and cellulose derivatives Cellulose acetate propionate as A substrate made of a material including A pressure-sensitive adhesive layer and death, the acetyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.5% or more and 3.0% or less; the content of propionyl groups in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 30% or more and 60% or less; the hydroxyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.3% or more and 10% or less; The number average molecular weight of the cellulose derivative is 8,000 or more and 100,000 or less, the content of the cellulose derivative in the base material is 2 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the polyvinyl chloride, The number average molecular weight of the polyvinyl chloride is 40,000 or more and 290,000 or less, The thickness of the substrate is 5 μm or more and 200 μm or less. A pressure-sensitive adhesive sheet characterized by:

[0012] (2) An adhesive sheet used for printing by an inkjet method, A substrate made of a material containing polyvinyl chloride and cellulose acetate butyrate as a cellulose derivative; and a pressure-sensitive adhesive layer; the acetyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.2% or more and 30% or less; the content of butyryl groups in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 20% or more and 50% or less; the hydroxyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.3% or more and 10% or less; The number average molecular weight of the cellulose derivative is 8,000 or more and 100,000 or less, the content of the cellulose derivative in the base material is 2 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the polyvinyl chloride, The number average molecular weight of the polyvinyl chloride is 40,000 or more and 290,000 or less, The thickness of the substrate is 5 μm or more and 200 μm or less. Adhesive sheet.

[0021] ( 3 ) Above (1) Or (2) 2. A printed matter comprising a printed layer formed by an inkjet method on the substrate of the pressure-sensitive adhesive sheet according to claim 1. Effect of the Invention

[0022] According to the present invention, it is possible to provide an adhesive sheet that has excellent weather resistance and other properties and is also excellent in printability by the inkjet method, and to provide a printed matter that has excellent weather resistance and other properties and has a printed area with excellent print quality with little bleeding and other problems when printed by the inkjet method. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic longitudinal sectional view showing a preferred embodiment of a pressure-sensitive adhesive sheet of the present invention. [Diagram 2] FIG. 1 is a schematic longitudinal sectional view showing a preferred embodiment of a printed matter of the present invention. [Diagram 3] FIG. 2 is a schematic longitudinal sectional view showing an example of a state in which the printed matter of the present invention is covered with a laminate sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Preferred embodiments of the present invention will now be described in detail. [1] Adhesive sheet First, the pressure-sensitive adhesive sheet of the present invention will be described.

[0025] FIG. 1 is a schematic longitudinal sectional view showing a preferred embodiment of the pressure-sensitive adhesive sheet of the present invention. The adhesive sheet 10 is used for printing by the inkjet method, and is characterized by having a substrate 11 made of a material containing polyvinyl chloride and a cellulose derivative, and an adhesive layer 12.

[0026] This makes it possible to provide a pressure-sensitive adhesive sheet that is excellent in weather resistance and printability by an inkjet method. Also, the adhesion between the substrate 11 and the pressure-sensitive adhesive layer 12 can be particularly excellent. Also, the properties such as weather resistance, film-forming ability, and flexibility can be excellent.

[0027] On the other hand, if the above-mentioned configuration is not met, such excellent effects cannot be obtained.

[0028] For example, if the substrate is made of a material that does not contain polyvinyl chloride, it becomes difficult to achieve sufficiently excellent weather resistance, conformability to curved or uneven surfaces, film-forming properties, flexibility, etc. for the entire adhesive sheet.

[0029] Furthermore, if the substrate is made of a material that does not contain a cellulose derivative, it is difficult to obtain a sufficiently excellent printability by the inkjet method. More specifically, when applied to printing by the inkjet method, the ink spreads too much, causing the image to bleed, making it difficult to form a clear image.

[0030] Furthermore, when a coating layer made of a material containing a cellulose derivative and no vinyl chloride is provided on a substrate made of polyvinyl chloride, the coating layer may easily crack or peel off from the substrate.

[0031] [1-1] Base material The substrate 11 is made of a material containing polyvinyl chloride and a cellulose derivative, and is the portion to be printed on by the inkjet method.

[0032] [1-1-1] Polyvinyl chloride Polyvinyl chloride is a material characterized by excellent weather resistance, flexibility, shape conformability, and the like.

[0033] The number average molecular weight of the polyvinyl chloride contained in the substrate 11 is preferably 40,000 or more and 290,000 or less, more preferably 70,000 or more and 200,000 or less, and even more preferably 100,000 or more and 120,000 or less.

[0034] This can improve the weather resistance, flexibility, shape conformity, etc. of the entire pressure-sensitive adhesive sheet 10. In addition, the affinity and compatibility between polyvinyl chloride and the cellulose derivative can be improved, and the effects obtained by the coexistence of polyvinyl chloride and the cellulose derivative as described above can be more significantly exhibited.

[0035] The number average molecular weight can be determined, for example, by a GPC method using a dimethylformamide solution of lithium bromide (concentration: 50 mM) as a solvent, in terms of polystyrene. The temperature during the measurement can be, for example, 80°C. The content of polyvinyl chloride in the substrate 11 is preferably 50% by mass or more.

[0036] [1-1-2] Cellulose derivatives The cellulose derivative in the pressure-sensitive adhesive sheet 10 mainly has the function of improving printability by the ink-jet method.

[0037] The cellulose derivative may be any derivative of cellulose, and examples thereof include compounds in which some of the hydroxyl groups of cellulose are esterified. More specifically, examples of the cellulose derivative include cellulose acetate in which at least a portion of the hydroxyl groups of cellulose are acetylated, cellulose propionate in which at least a portion of the hydroxyl groups of cellulose are propionylated, cellulose butyrate in which at least a portion of the hydroxyl groups of cellulose are butyrylated, cellulose acetate propionate in which a portion of the hydroxyl groups of cellulose are acetylated and at least a portion of the other hydroxyl groups of cellulose are propionylated, and cellulose acetate butyrate in which a portion of the hydroxyl groups of cellulose are acetylated and at least a portion of the other hydroxyl groups of cellulose are butyrylated. These derivatives may be used alone or in combination of two or more. Preferably, they are cellulose ester derivatives, more preferably at least one of cellulose acetate propionate and cellulose acetate butyrate, and even more preferably, cellulose acetate propionate. This makes the above-mentioned effects more pronounced.

[0038] The content of acetyl groups in the cellulose derivative (the cellulose derivative constituting the substrate 11) determined by measurement in accordance with ASTM D817-12 is preferably 0.2% or more and 30% or less, more preferably 0.4% or more and 15% or less, and even more preferably 0.5% or more and 3.0% or less. This makes the above-mentioned effects more pronounced.

[0039] The propionyl group content in the cellulose derivative (the cellulose derivative constituting the substrate 11) determined by measurement in accordance with ASTM D817-12 is preferably 30% or more and 60% or less, more preferably 35% or more and 55% or less, and even more preferably 40% or more and 50% or less. This makes the above-mentioned effects more pronounced.

[0040] The butyryl group content in the cellulose derivative (the cellulose derivative constituting the substrate 11) determined by measurement in accordance with ASTM D817-12 is preferably 20% or more and 50% or less, more preferably 25% or more and 45% or less, and even more preferably 35% or more and 40% or less. This makes the above-mentioned effects more pronounced.

[0041] The hydroxyl group content in the cellulose derivative (the cellulose derivative constituting the substrate 11), determined by measurement in accordance with ASTM D817-12, is preferably 0.3% or more and 10% or less, more preferably 0.8% or more and 10% or less, and even more preferably 1.5% or more and 7.0% or less. This makes the above-mentioned effects more pronounced.

[0042] The number average molecular weight of the cellulose derivative contained in the substrate 11 is preferably 8,000 or more and 100,000 or less, more preferably 10,000 or more and 80,000 or less, and even more preferably 15,000 or more and 40,000 or less.

[0043] This can improve the printability of the pressure-sensitive adhesive sheet 10 by an inkjet method. Also, the affinity and compatibility between polyvinyl chloride and the cellulose derivative can be improved, and the above-mentioned effect obtained by the coexistence of polyvinyl chloride and the cellulose derivative can be more significantly exhibited.

[0044] The content of the cellulose derivative in the substrate 11 is preferably 1.0% by mass or more, and more preferably 1.9% by mass or more.

[0045] The content of the cellulose derivative in the substrate 11 relative to 100 parts by mass of polyvinyl chloride is preferably 2 parts by mass or more and 20 parts by mass or less, more preferably 3 parts by mass or more and 15 parts by mass or less, and even more preferably 5 parts by mass or more and 10 parts by mass or less. This makes it possible to achieve a better balance of the above-mentioned characteristics.

[0046] [1-1-3] Plasticizers The substrate 11 may contain a plasticizer in addition to the above-mentioned polyvinyl chloride and cellulose derivative. A plasticizer is usually used to improve flexibility.

[0047] Examples of the plasticizer include phthalate ester plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, di-n-octyl phthalate, and dicyclohexyl phthalate; trimellitate ester plasticizers such as trioctyl trimellitate, triisononyl trimellitate, and triisodecyl trimellitate; adipic acid plasticizers such as dioctyl adipate, diisononyl adipate, and diisodecyl adipate; polyester plasticizers such as phthalic acid polyesters; phosphate ester plasticizers such as tricresyl phosphate, trioctyl phosphate, and triphenyl phosphate; and epoxy plasticizers such as epoxidized linseed oil and epoxidized butyl stearate.

[0048] The weight average molecular weight of the polyester plasticizer is preferably 2,000 or more and 6,000 or less.

[0049] The content of the plasticizer is preferably 25 parts by mass or more and 40 parts by mass or less, and more preferably 27 parts by mass or more and 35 parts by mass or less, based on 100 parts by mass of polyvinyl chloride.

[0050] [1-1-4] Colorants The substrate 11 may include a colorant.

[0051] As the colorant, for example, various pigments and various dyes can be used, but from the viewpoint of light resistance and the like, pigments are preferred.

[0052] When the base material 11 is made white, for example, titanium oxide can be suitably used as the colorant (pigment).

[0053] [1-1-5] Other ingredients The substrate 11 may contain components other than the above-mentioned components. Examples of such components include resin materials other than polyvinyl chloride, cellulose, various fillers, surfactants, dispersants, UV absorbers, antistatic agents, leveling agents, antioxidants, pH adjusters, preservatives, rust inhibitors, deodorizers, antibacterial agents, antifungal agents, antiviral agents, germicides, crosslinking agents, polymerization initiators, fixing agents, and flocculants.

[0054] However, the content of components other than polyvinyl chloride, cellulose derivatives, plasticizers, and colorants in the base material 11 is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of polyvinyl chloride.

[0055] [1-1-6] Other conditions of the substrate The substrate 11 may have a substantially uniform composition throughout, or may have portions with different compositions. For example, the substrate 11 may be made of a gradient material whose composition changes in a gradient manner in the thickness direction, or may be a laminate having a plurality of layers. Also, different portions in the plane of the substrate 11 may have different compositions.

[0056] The thickness of the substrate 11 is preferably 5 μm or more and 200 μm or less, and more preferably 30 μm or more and 100 μm or less.

[0057] This makes it possible to achieve a higher level of both flexibility and durability in the pressure-sensitive adhesive sheet 10. In addition, the pressure-sensitive adhesive sheet 10 can be made easier to handle when adhering it to an adherend.

[0058] As the substrate 11, for example, one obtained by a solution casting method using a solution in which the above-mentioned components are dissolved in a solvent can be suitably used, but the method for producing the substrate 11 is not particularly limited, and the substrate 11 may be produced, for example, by a calendar method.

[0059] [1-2] Adhesive layer The adhesive layer 12 is made of a material containing an adhesive, and is the portion that comes into contact with the adherend when the sheet is attached to the adherend.

[0060] [1-2-1] Adhesive The adhesive constituting the adhesive layer 12 is not particularly limited, and examples thereof include acrylic adhesives, rubber adhesives, silicone adhesives, polyurethane adhesives, and polyester adhesives.

[0061] Among these, acrylic adhesives are preferred. Acrylic adhesives are generally prepared by crosslinking a copolymer of a (meth)acrylic acid alkyl ester monomer that provides adhesiveness and a monomer containing a functional group with a crosslinking agent.

[0062] Examples of (meth)acrylic acid alkyl esters that impart adhesion include butyl acrylate and 2-ethylhexyl acrylate.

[0063] Examples of the monomer containing a functional group include 2-hydroxyethyl (meth)acrylate and (meth)acrylic acid.

[0064] Examples of the crosslinking agent include an isocyanate compound, an epoxy compound, and a metal chelate compound.

[0065] [1-2-2] Other ingredients The adhesive layer 12 may contain components other than the above-mentioned adhesives. Examples of such components include tackifiers, plasticizers, colorants such as pigments and dyes, various fillers, surfactants, dispersants, UV absorbers, antistatic agents, leveling agents, antioxidants, pH adjusters, preservatives, rust inhibitors, deodorants, antibacterial agents, antifungal agents, antiviral agents, germicides, crosslinking agents, and polymerization initiators.

[0066] Examples of tackifiers that can be used include rosin, rosin phenol resins, and their ester compounds, rosin-based resins such as hydrogenated rosin esters, terpene low polymers, terpene phenol resins, terpene-based resins such as aromatic modified terpene resins, C5 petroleum resins, C9 petroleum resins, etc. More preferably, hydrogenated rosin esters and / or aromatic modified terpene resins can be used.

[0067] However, the content of components other than the adhesive in the adhesive layer 12 is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0068] [1-2-3] Other conditions of the adhesive layer The adhesive layer 12 may have a substantially uniform composition throughout, or may have portions with different compositions. For example, the adhesive layer 12 may be made of a gradient material whose composition changes in a gradient manner in the thickness direction, or may be a laminate having a plurality of layers. Also, different portions in the plane of the adhesive layer 12 may have different compositions.

[0069] The thickness of the pressure-sensitive adhesive layer 12 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 60 μm or less.

[0070] The adhesive layer 12 can be formed, for example, by applying a composition for forming the adhesive layer 12 onto the substrate 11 described above, or by applying a composition for forming the adhesive layer 12 onto a release liner 20 described below and transferring it to the substrate 11.

[0071] [1-3] Overall structure of adhesive sheet Adhesive sheet 10 only needs to have substrate 11 and adhesive layer 12 described above, and may further have at least one intermediate layer (not shown) between substrate 11 and adhesive layer 12.

[0072] The thickness of the adhesive sheet 10 is preferably 10 μm or more and 300 μm or less, and more preferably 40 μm or more and 160 μm or less.

[0073] This makes it possible to achieve a higher level of both flexibility and durability in the pressure-sensitive adhesive sheet 10. In addition, the pressure-sensitive adhesive sheet 10 can be made easier to handle when adhering it to an adherend.

[0074] [1-4] Release liner The surface of the adhesive layer 12 of an unused adhesive sheet 10 is preferably covered with a release liner 20, as shown in FIG.

[0075] This makes it easier to handle unused pressure-sensitive adhesive sheet 10 and also provides suitable protection for pressure-sensitive adhesive layer 12 before it is attached to an adherend.

[0076] The release liner 20 may be, for example, a sheet made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, polyarylate, etc., or a base material made of various paper materials such as polyethylene laminated paper, polypropylene laminated paper, clay coated paper, resin coated paper, glassine paper, and high-quality paper, with a release treatment applied, if necessary, to the contact surface of the base material with the adhesive layer 12.

[0077] The release treatment may involve the formation of a release agent layer made of a release agent such as a silicone resin, a long-chain alkyl resin, or a fluorine resin.

[0078] [2] Printed matter Next, the printed matter of the present invention will be described.

[0079] Fig. 2 is a schematic vertical cross-sectional view showing a preferred embodiment of the printed matter of the present invention, and Fig. 3 is a schematic vertical cross-sectional view showing an example of a state in which the printed matter of the present invention is covered with a laminate sheet.

[0080] The printed matter 100 is characterized in that a printed layer 30 is formed on a substrate 11 of an adhesive sheet 10 by an inkjet method.

[0081] This makes it possible to provide a printed matter having a printed portion with excellent print quality that is excellent in weather resistance and has little bleeding due to the inkjet method.

[0082] The ink used to form the printed layer 30 is not particularly limited, and examples thereof include oil-based ink, water-based ink, latex ink, photocurable ink (ultraviolet ray curable ink, electron beam curable ink), etc. Among these, oil-based ink and latex ink are more preferable.

[0083] Conventionally, when such inks were used to form a printed layer by the inkjet method, the above-mentioned problems were particularly likely to occur, but according to the present invention, even when such inks are used, the occurrence of the above-mentioned problems can be effectively prevented. In other words, when the above-mentioned inks are used to form the printed layer 30, the effects of the present invention are more pronounced.

[0084] Furthermore, the printed layer 30 may be formed by using a combination of two or more types of ink. In the illustrated configuration, the printed layer 30 is provided on the entire surface of the substrate 11 , but the printed layer 30 may be provided on only a portion of the surface of the substrate 11 .

[0085] The printed layer 30 may be formed before the adhesive sheet 10 is attached to the adherend, or may be formed after the adhesive sheet 10 is attached to the adherend. The display content etc. of the print layer 30 is not particularly limited.

[0086] The printed matter 100 may be used as is by adhering it to an adherend, or, for example, as shown in FIG. 3, the surface on which the printed layer 30 is provided may be covered with a laminate sheet 200 for use.

[0087] The configuration of the laminate sheet 200 is not particularly limited, but in the illustrated configuration, the laminate sheet 200 has a laminate sheet substrate 50 and an adhesive layer 60 .

[0088] The laminate sheet substrate 50 may be made of any material, but is usually made mainly of a resin material.

[0089] Examples of the resin material constituting the laminate sheet substrate 50 include polyvinyl chloride, acrylic resin, and fluorine-based resin.

[0090] The laminate sheet substrate 50 may contain components other than the resin material, such as colorants such as pigments and dyes, various fillers, dispersants, UV absorbers, antioxidants, pH adjusters, preservatives, rust inhibitors, deodorizers, antibacterial agents, antifungal agents, antiviral agents, germicides, crosslinking agents, polymerization initiators, fixing agents, and flocculants.

[0091] However, the content of components other than the resin material in the laminate sheet substrate 50 is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0092] The laminate sheet substrate 50 may have a substantially uniform composition throughout, or may have portions with different compositions. For example, the laminate sheet substrate 50 may be made of a gradient material whose composition changes in a gradient manner in the thickness direction, or may be a laminate having a plurality of layers. Also, different portions in the plane of the laminate sheet substrate 50 may have different compositions.

[0093] The thickness of the laminate sheet substrate 50 is preferably 10 μm or more and 100 μm or less, and more preferably 20 μm or more and 80 μm or less.

[0094] The adhesive layer 60 is made of a material containing an adhesive, and is the portion that comes into contact with the surface of the printed matter 100 on which the printed layer 30 is provided.

[0095] The adhesive constituting the adhesive layer 60 is not particularly limited, and examples thereof include acrylic adhesives, rubber adhesives, silicone adhesives, polyurethane adhesives, and polyester adhesives.

[0096] The adhesive layer 60 may contain components other than the adhesive. Examples of such components include tackifiers, plasticizers, colorants such as pigments and dyes, various fillers, dispersants, UV absorbers, antioxidants, pH adjusters, preservatives, rust inhibitors, deodorizers, antibacterial agents, antifungal agents, antiviral agents, germicides, crosslinking agents, and polymerization initiators.

[0097] However, the content of components other than the adhesive in the adhesive layer 60 is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0098] The adhesive layer 60 may have a substantially uniform composition throughout, or may have portions with different compositions. For example, the adhesive layer 60 may be made of a gradient material whose composition changes in a gradient manner in the thickness direction, or may be a laminate having a plurality of layers. Also, different portions in the plane of the adhesive layer 60 may have different compositions.

[0099] The thickness of the pressure-sensitive adhesive layer 60 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 60 μm or less.

[0100] When covering the printed matter 100 with the laminate sheet 200, the covering of the printed matter 100 with the laminate sheet 200 may be performed before or after the printed matter 100 is attached to the substrate.

[0101] The printed matter of the present invention can be used for various public relations, advertisements, signboards, etc. These include, for example, wrapping of vehicle bodies, attachment to wall surfaces, etc.

[0102] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0103] For example, in the illustrated configuration, the printed layer is provided on the substrate, but a portion of the printed layer may penetrate into the substrate. EXAMPLES

[0104] The present invention will be described in detail below with reference to specific examples, but the present invention is not limited thereto. In the following examples, the treatments and measurements were performed at 25° C. unless otherwise specified.

[0105] [3] Manufacturing of adhesive sheets Example 1 First, polyvinyl chloride having a number average molecular weight of 120,000, cellulose acetate propionate as a cellulose derivative having a number average molecular weight of 25,000 and an acetyl group content of 2.5%, a propionyl group content of 45.0%, and a hydroxyl group content of 2.6%, as determined by measurement in accordance with ASTM D817-12, and titanium oxide as a pigment were prepared, and these were dissolved in a predetermined ratio in a mixture of ethylene glycol monobutyl ether and trimethylbenzene as a solvent.

[0106] The thus obtained solution was subjected to solution casting to obtain a substrate having a thickness of 50 μm.

[0107] On the other hand, the pressure-sensitive adhesive composition was applied onto the release agent-treated surface of a release liner using a roll knife coater so that the coating thickness after drying would be 15 μm, and then dried at 90° C. for 1 minute. As the adhesive composition, an acrylic adhesive was used.

[0108] Thereafter, this pressure-sensitive adhesive composition was brought into contact with the substrate produced as described above to obtain a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer was protected by a release liner.

[0109] (Examples 2 to 7) Except for the fact that the adhesive sheet had the configuration shown in Table 1, an adhesive sheet was produced in the same manner as in Example 1 above.

[0110] Comparative Example 1 An adhesive sheet was produced in the same manner as in Example 1, except that the substrate did not contain a cellulose derivative and was made of polyvinyl chloride.

[0111] The configurations of the pressure-sensitive adhesive sheets of the above-mentioned Examples and Comparative Example 1 are summarized in Table 1. In Table 1, polyvinyl chloride having a number average molecular weight of 120,000 is designated as "PVC1", cellulose acetate propionate as a cellulose derivative having a number average molecular weight of 25,000 and an acetyl group content of 2.5%, a propionyl group content of 45.0%, and a hydroxyl group content of 2.6%, as determined by measurement in accordance with ASTM D817-12, is designated as "CAP1", cellulose acetate propionate as a cellulose derivative having a number average molecular weight of 15,000 and an acetyl group content of 0.6%, a propionyl group content of 42.5%, and a hydroxyl group content of 5.0%, as determined by measurement in accordance with ASTM D817-12, is designated as "CAP2", and cellulose acetate propionate as a cellulose derivative having a number average molecular weight of 20,000 and an acetyl group content of 2.5%, a propionyl group content of 45.0%, and a hydroxyl group content of 2.6%, as determined by measurement in accordance with ASTM D817-12, is designated as "CAP3". Cellulose acetate butyrate, a cellulose derivative having an acetyl group content of 13.5%, a butyryl group content of 38.0%, and a hydroxyl group content of 1.3%, as determined by a measurement in accordance with D817-12, was designated "CAB1."

[0112] [Table 1]

[0113] [4] Production of printed matter A printed layer having a predetermined pattern was formed by an inkjet method using an inkjet printer (JV33-130, manufactured by Mimaki Engineering Co., Ltd.) on the surface of the substrate side of the pressure-sensitive adhesive sheet of each of the Examples and Comparative Example 1, to obtain a printed matter.

[0114] In this case, the ink used was SS21 ink (manufactured by Mimaki Engineering Co., Ltd.), which is a solvent-based ink (oil-based ink).

[0115] [5] Evaluation The printed matter of each of the Examples and Comparative Example 1 was evaluated as follows.

[0116] [5-1] Appearance evaluation The surface of the printed matter of each of the Examples and Comparative Example 1 on which the printed layer was formed was visually observed and evaluated according to the following criteria.

[0117] A: A very clear appearance with no visible bleeding. B: The appearance is sufficiently clear with almost no bleeding observed. C: Although slight bleeding is observed, the appearance is relatively clear. D: Blurring is clearly observed and clarity is insufficient. E: Significant bleeding is observed, resulting in an unclear appearance.

[0118] [5-2] Weather resistance evaluation The pressure-sensitive adhesive sheets of each of the Examples and Comparative Example 1 were attached to an acrylic-coated plate and subjected to an accelerated weather resistance test for 2000 hours using a sunshine weather meter, and were evaluated according to the following criteria.

[0119] A: No cracks or yellowing are observed. B: Slight cracks or yellowing are observed. C: Cracks and yellowing are clearly observed. These results are summarized in Table 2.

[0120] [Table 2]

[0121] As is clear from Table 2, excellent results were obtained with the pressure-sensitive adhesive sheets of the above-mentioned Examples. In contrast, satisfactory results were not obtained with the pressure-sensitive adhesive sheet of Comparative Example 1.

[0122] In addition, for the adhesive sheets of each of the above examples and Comparative Example 1, printed matter was produced in the same manner as described above, except that an HP Latex printer manufactured by HP was used to form the printed layer, and evaluation was performed in the same manner as described above. In all cases, the same results as described above were obtained. [Explanation of symbols]

[0123] 10...Adhesive sheet 11...Base material 12...Adhesive layer 20…Release liner 30…printing layer 50...Laminate sheet base material 60...Adhesive layer 100…Printed material 200…Laminate sheet

Claims

1. An adhesive sheet used for printing by an inkjet method, A substrate made of a material containing polyvinyl chloride and cellulose acetate propionate as a cellulose derivative; and a pressure-sensitive adhesive layer; the acetyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.5% or more and 3.0% or less; the content of propionyl groups in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 30% or more and 60% or less; the hydroxyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.3% or more and 10% or less; The number average molecular weight of the cellulose derivative is 8,000 or more and 100,000 or less, the content of the cellulose derivative in the base material is 2 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the polyvinyl chloride, The number average molecular weight of the polyvinyl chloride is 40,000 or more and 290,000 or less, A pressure-sensitive adhesive sheet characterized in that the thickness of the substrate is 5 μm or more and 200 μm or less.

2. An adhesive sheet used for printing by an inkjet method, A substrate made of a material containing polyvinyl chloride and cellulose acetate butyrate as a cellulose derivative; and a pressure-sensitive adhesive layer; the acetyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.2% or more and 30% or less; the content of butyryl groups in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 20% or more and 50% or less; the hydroxyl group content in the cellulose derivative as determined by measurement in accordance with ASTM D817-12 is 0.3% or more and 10% or less; The number average molecular weight of the cellulose derivative is 8,000 or more and 100,000 or less, the content of the cellulose derivative in the base material is 2 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the polyvinyl chloride, The number average molecular weight of the polyvinyl chloride is 40,000 or more and 290,000 or less, A pressure-sensitive adhesive sheet characterized in that the thickness of the substrate is 5 μm or more and 200 μm or less.

3. A printed matter, comprising a printed layer formed by an inkjet method on the substrate of the pressure-sensitive adhesive sheet according to claim 1 or 2.

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