JP7601485B2 - Adhesive sheets and printed matter - Google Patents

Description

The present invention relates to adhesive sheets and printed matter.

Because of its excellent weather resistance and ability to conform to curved or uneven surfaces, polyvinyl chloride sheets have traditionally been widely used as decorative adhesive sheets for advertisements, signs, etc.

For advertising, signboards, and other uses, replacement is often required at relatively short intervals, and small lot production is sometimes required.

On the other hand, inkjet printing has the advantage of being on-demand and suitable for producing a large number of printed items in small quantities.

The inkjet method is also increasingly being used for printing on decorative adhesive sheets.

However, when printing on conventional polyvinyl chloride using the inkjet method, there was a problem in that the inkjet printing tended to be unclear.

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

However, even with this type of sheet material, it was not possible to obtain sufficiently excellent printability using the inkjet method.

Patent No. 3745993

The object of the present invention is to provide an adhesive sheet that has excellent weather resistance and other properties and is suitable for printing by the inkjet method, and to provide a printed matter that has excellent weather resistance and other properties and has a printed part with excellent printing quality with little bleeding and other problems when printed by the inkjet method.

These objects can be achieved by the present invention described in (1) to ( 3 ) below.
(1) A pressure-sensitive 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) A pressure-sensitive 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, characterized in that a printed layer is formed by an inkjet method on the substrate of the pressure-sensitive adhesive sheet according to (1) or (2) above.

The present invention can provide an adhesive sheet that is excellent in weather resistance and other properties and is suitable for printing by the inkjet method, and can also provide a printed matter that is excellent in weather resistance and other properties and has a printed part with excellent printing quality with little bleeding and other problems when printed by the inkjet method.

1 is a schematic longitudinal sectional view showing a preferred embodiment of a pressure-sensitive adhesive sheet of the present invention. FIG. 1 is a schematic longitudinal sectional view showing a preferred embodiment of a printed matter of the present invention. 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.

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

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 an adhesive sheet 10 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.

This makes it possible to provide an adhesive sheet that has excellent weather resistance and excellent printability by the inkjet method. In addition, the adhesion between the substrate 11 and the adhesive layer 12 can be particularly excellent. In addition, the properties such as weather resistance, film-forming ability, and flexibility can also be excellent.

On the other hand, if the above configuration is not met, such excellent effects will not be obtained.

For example, if the substrate is made of a material that does not contain polyvinyl chloride, it will be difficult to provide the adhesive sheet as a whole with sufficiently excellent weather resistance, conformability to curved or uneven surfaces, film-forming properties, flexibility, etc.

Furthermore, if the substrate is made of a material that does not contain a cellulose derivative, it is difficult to achieve 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.

In addition, if a coating layer made of a material that contains a cellulose derivative but does not contain vinyl chloride is provided on a substrate made of polyvinyl chloride, the coating layer may crack or peel off from the substrate.

[1-1] Substrate The substrate 11 is made of a material containing polyvinyl chloride and a cellulose derivative, and is the portion on which printing is performed by the inkjet method.

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

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.

This makes it possible to improve the weather resistance, flexibility, shape conformity, etc. of the adhesive sheet 10 as a whole. In addition, it makes it possible to improve the affinity and compatibility between polyvinyl chloride and cellulose derivatives, and to more significantly exert the effects obtained by the coexistence of polyvinyl chloride and cellulose derivatives as described above.

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.

[1-1-2] Cellulose Derivatives In the pressure-sensitive adhesive sheet 10, the cellulose derivatives mainly have the function of improving the printability by the inkjet method.

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 is acetylated and at least a portion of the other hydroxyl groups of cellulose is propionylated, and cellulose acetate butyrate in which a portion of the hydroxyl groups of cellulose is acetylated and at least a portion of the other hydroxyl groups of cellulose is butyrylated. One or a combination of two or more selected from these can be used, but a cellulose ester derivative is preferred, and at least one of cellulose acetate propionate and cellulose acetate butyrate is more preferred, with cellulose acetate propionate being even more preferred.
This makes the above-mentioned effects more pronounced.

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.

The propionyl group content in the cellulose derivative (the cellulose derivative constituting the substrate 11) determined by the 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.

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.

The content of hydroxyl groups 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.

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.

This makes it possible to improve the printability of the adhesive sheet 10 by the inkjet method. It also makes it possible to improve the affinity and compatibility between polyvinyl chloride and the cellulose derivative, and to more significantly exhibit the effects obtained by the coexistence of polyvinyl chloride and the cellulose derivative as described above.

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.

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.

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

Examples of plasticizers 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.

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

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, per 100 parts by mass of polyvinyl chloride.

[1-1-4] Colorant The substrate 11 may contain a colorant.

As colorants, for example, various pigments and dyes can be used, but pigments are preferred from the standpoint of light resistance, etc.

If the substrate 11 is to be white, then titanium oxide, for example, can be suitably used as the colorant (pigment).

[1-1-5] Other Components 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, deodorants, antibacterial agents, antifungal agents, antiviral agents, germicides, crosslinking agents, polymerization initiators, fixing agents, and flocculants.

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.

[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.

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.

This allows the adhesive sheet 10 to achieve both flexibility and durability at a higher level. It also makes the adhesive sheet 10 easier to handle when adhering it to an adherend.

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 it may be produced, for example, by a calendar method.

[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.

[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.

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

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

Examples of monomers containing functional groups include 2-hydroxyethyl (meth)acrylate and (meth)acrylic acid.

Examples of cross-linking agents include isocyanate compounds, epoxy compounds, and metal chelate compounds.

[1-2-2] Other Components 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.

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

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.

[1-2-3] Other Conditions of the Pressure-Sensitive Adhesive Layer The pressure-sensitive adhesive layer 12 may have a substantially uniform composition throughout, or may have portions with different compositions. For example, the pressure-sensitive 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 of the surface of the pressure-sensitive adhesive layer 12 may have different compositions.

The thickness of the 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.

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 the composition to the substrate 11.

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

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.

This allows the adhesive sheet 10 to achieve both flexibility and durability at a higher level. It also makes the adhesive sheet 10 easier to handle when adhering it to an adherend.

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

This makes it easier to handle unused adhesive sheet 10 and provides optimal protection for adhesive layer 12 before it is attached to the adherend.

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 fine paper, with a release treatment applied, if necessary, to the surface of the base material that comes into contact with the adhesive layer 12.

Examples of the release treatment include forming a release agent layer made of a release agent such as a silicone resin, a long-chain alkyl resin, or a fluorine resin.

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

Figure 2 is a schematic vertical cross-sectional view showing a preferred embodiment of the printed matter of the present invention. Figure 3 is a schematic vertical cross-sectional view showing an example of the printed matter of the present invention covered with a laminate sheet.

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

This makes it possible to provide printed matter with excellent weather resistance and other properties, as well as excellent print quality with minimal bleeding due to the inkjet method.

The ink used to form the printing layer 30 is not particularly limited, and examples include oil-based ink, water-based ink, latex ink, photocurable ink (ultraviolet light curable ink, electron beam curable ink), etc. Among these, oil-based ink and latex ink are more preferred.

Conventionally, when such inks were used to form a printing layer by the inkjet method, the problems described above were particularly likely to occur. However, according to the present invention, even when such inks are used, the occurrence of the problems described above can be effectively prevented. In other words, when the inks described above are used to form the printing layer 30, the effects of the present invention are more pronounced.

Furthermore, the printing 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 .

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 of the print layer 30 is not particularly limited.

The printed matter 100 may be used as is, attached 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.

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

The laminate sheet substrate 50 may be made of any material, but is typically made primarily of a resin material.

Examples of the resin material that constitutes the laminate sheet substrate 50 include polyvinyl chloride, acrylic resin, and fluorine-based resin.

The laminate sheet substrate 50 may contain components other than the resin material. Examples of such components include 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 coagulants.

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.

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 multiple layers. Also, different portions within the plane of the laminate sheet substrate 50 may have different compositions.

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.

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

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

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.

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.

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 multiple layers. Also, different portions within the plane of the adhesive layer 60 may have different compositions.

The thickness of the 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.

When the printed matter 100 is covered with the laminate sheet 200, the laminate sheet 200 may be applied to the printed matter 100 before or after the printed matter 100 is attached to the substrate.

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

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

For example, in the illustrated configuration, the printed layer is provided on the substrate, but part of the printed layer may penetrate into the substrate.

The present invention will be described in detail below based on specific examples, but the present invention is not limited to these. In the following examples, treatments and measurements that do not indicate temperature conditions were performed at 25°C.

[3] Production of adhesive sheet (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%, which are 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.

A substrate with a thickness of 50 μm was obtained by solution casting using the solution obtained in this way.

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.

Then, this adhesive composition was brought into contact with the substrate prepared as described above to obtain an adhesive sheet in which the adhesive layer was protected by a release liner.

(Examples 2 to 7)
Except for the fact that the pressure-sensitive adhesive sheet had the configuration shown in Table 1, a pressure-sensitive adhesive sheet was produced in the same manner as in Example 1.

(Comparative Example 1)
A pressure-sensitive 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.

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 measured 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 measured 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 measured in accordance with ASTM D817-12, is designated as "CAP3". "CAB1" denotes cellulose acetate butyrate, a cellulose derivative with 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 measurements in accordance with D817-12.

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

The ink used was SS21 ink (manufactured by Mimaki Engineering Co., Ltd.), a solvent-based ink (oil-based ink).

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

[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 provided was visually observed and evaluated according to the following criteria.

A: A very clear appearance with absolutely no bleeding observed.
B: Almost no bleeding is observed and the appearance is sufficiently clear.
C: Although slight bleeding is observed, the appearance is relatively clear.
D: Blurring is clearly observed and the image is not clear enough.
E: Blurring is noticeable, and the appearance is unclear.

[5-2] Weather Resistance Evaluation The pressure-sensitive adhesive sheets of the above 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.

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

As is clear from Table 2, excellent results were obtained with the adhesive sheets of the above examples. In contrast, satisfactory results were not obtained with the adhesive sheet of Comparative Example 1.

In addition, for the pressure-sensitive adhesive sheets of each of the above examples and Comparative Example 1, prints were produced in the same manner as above, except that an HP Latex printer manufactured by HP was used to form the print layer, and evaluations were performed in the same manner as above. In all cases, the same results as above were obtained.

REFERENCE SIGNS LIST 10: Adhesive sheet 11: Substrate 12: Adhesive layer 20: Release liner 30: Printed layer 50: Laminate sheet substrate 60: Adhesive layer 100: Printed matter 200: Laminate sheet

Claims (3)

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 . 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 . 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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