JP2022102660A - Printed face-protecting film and multilayer body, and package and packaged article - Google Patents

Abstract

To provide a printed face-protecting film having excellent heat lamination suitability and moist heat resistance.SOLUTION: A printed face-protecting film at least contains: a substrate layer primarily composed of a thermoplastic resin (A); and a sealant layer comprising a resin composition that is primarily composed of a cyclic ether group-containing thermoplastic elastomer (B) and having a flow start temperature of 80°C or higher and 105°C or lower.SELECTED DRAWING: None

Description

The present invention relates to a printed surface protective film and a multilayer body, and a packaged body and a packaged article.

Liquid toner is attracting attention as a technique for printing on containers and packaging of beverages, foods, daily necessities, etc. It is known that liquid toner can develop a color with a thinner film than conventional toner, and can improve the resolution of printed images.

In order to impart chargeability to the liquid toner, a polymer having an ionic group is used as a material.
For example, Patent Document 1 proposes a liquid toner in which a pigment is added to a polymer having a maleic anhydride functional group and an ethylene methacrylic acid copolymer and dispersed in a paraffin hydrocarbon fraction. This liquid toner exhibits excellent binding properties due to the interaction between the carboxyl group contained in maleic anhydride and the hydroxyl group of the base paper.

Special Table 2003-520997 Gazette

However, the printed matter obtained by using the liquid toner may be deteriorated or deformed in a moist heat environment such as a retort. Water resistance can be improved by thermally laminating a protective film on the printed matter, but the resistance to a high humidity and heat environment is insufficient.
Therefore, an object of the present invention is to provide a printed surface protective film having excellent thermal laminating suitability and moisture heat resistance.

As a result of diligent studies to achieve the above problems, the present inventor has completed the present invention focusing on solving the problems. That is, the gist of the present invention is as follows.

[1] It has at least a base material layer and a sealant layer, and has at least a base material layer and a sealant layer.
The base material layer contains the thermoplastic resin (A) as a main component and contains.
A printed surface protective film in which the sealant layer comprises a resin composition containing a cyclic ether group-containing thermoplastic elastomer (B) as a main component, and the flow start temperature of the resin composition is 80 ° C. or higher and 105 ° C. or lower.
[2] The printed surface protective film according to the above [1], wherein the base material layer has a thickness of 5 μm or more and 50 μm or less.
[3] The printed surface protective film according to the above [1] or [2], wherein the sealant layer has a thickness of 1 μm or more and 30 μm or less.
[4] The printed surface protective film according to any one of [1] to [3] above, wherein the thermoplastic resin (A) is at least one selected from the group consisting of polyester resin and polyolefin resin. ..
[5] The item according to any one of [1] to [4] above, wherein the cyclic ether group-containing thermoplastic elastomer (B) contains an epoxy group and has an epoxy equivalent of 500 g / eq or more and 3000 g / eq or less. Print surface protective film.
[6] The printed surface protective film according to any one of [1] to [5] above, wherein the cyclic ether group-containing thermoplastic elastomer (B) is a cyclic ether-modified product of a conjugated diene-based polymer.
[7] The conjugated diene-based polymer is a copolymer of at least one of butadiene, isoprene, and chloroprene, or acrylonitrile and butadiene rubber, and at least one of styrene and olefin, and hydrogenated thereof. The printed surface protective film according to the above [6], which is at least one selected from the group consisting of objects.
[8] The printed surface protective film according to any one of [1] to [7] above, which has a release layer on the side of the sealant layer opposite to the surface facing the base material layer.
[9] A multilayer body comprising the print surface protective film according to any one of the above [1] to [8] and a print layer, and the print surface protective film is heat-laminated on the print layer.
[10] The multilayer body according to the above [9], wherein the print layer is formed of liquid toner.
[11] The multilayer body according to the above [10], wherein the liquid toner contains a carboxyl group-containing polymer.
[12] A package having the multilayer body according to any one of the above [9] to [11].
[13] A packaged article packaged by the package according to the above [12].

The printed surface protective film proposed by the present invention is excellent in heat laminating suitability and moisture heat resistance.

Hereinafter, embodiments of the present invention will be described in detail. However, the content of the present invention is not limited to the embodiments described below.

<Printed surface protective film>
The printed surface protective film in the present invention (hereinafter, may be referred to as “the present film”) has at least a base material layer and a sealant layer. The sealant layer may be provided on at least one surface of the base material layer, the sealant layer may be laminated directly on the surface of the base material layer, or may be appropriately separated between the sealant layer and the base material layer. Layers may be provided.
This film may have a release layer on the side opposite to the surface of the sealant layer facing the base material layer.
The sealant layer may form the outermost surface of the film when there is no release layer, and when a release layer is provided, it may be a layer that comes into direct contact with the release layer.
Further, for the purpose of further imparting a function, a multilayer structure may be provided having at least one layer selected from a protective layer, an antireflection layer, an antibacterial layer, a smooth layer, a hard coat layer and the like. However, when this film has a multilayer structure, it is preferable that the number of layers other than the base material layer, the sealant layer and the release layer is 5 or less from the viewpoint of transparency.

[Aptitude for thermal laminating]
This film has good thermal laminating suitability for printed matter.
The thermal laminating suitability in the present invention can be evaluated by adhering the film and the printed matter through a heated nip roll and then measuring the peel strength.

[Moisture and heat resistance]
Moisture heat resistance can be improved by heat-laminating this film on printed matter.
The moist heat resistance in the present invention means that the film and the printed matter do not peel off even in a moist heat environment, and indicates retort resistance. More specifically, the sample obtained after thermally laminating the present film and the printed matter can be evaluated by allowing it to stand under pressurized hot steam at 120 ° C. for 0.5 hours and then observing the appearance. ..

[thickness]
The thickness of this film is preferably 6 μm or more and 80 μm or less, more preferably 8 μm or more and 60 μm or less, and further preferably 10 μm or more and 40 μm or less. The thickness of this film is the thickness excluding the release layer when the release layer is provided.
When the thickness of this film is 6 μm or more, the transportability and handleability at the time of thermal laminating are improved. On the other hand, when the thickness is 80 μm or less, the transparency of this film is good.

Hereinafter, each layer will be described.

1. 1. Base material layer The base material layer in the present invention contains the thermoplastic resin (A) as a main component. In this film, the substrate layer contains the thermoplastic resin (A) as a main component, so that the heat laminating suitability can be obtained.
In the present invention, the "main component" is 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and more, among all the components constituting the layer. More preferably, it refers to a component that occupies 90% by mass or more (including 100% by mass).

[Thermoplastic resin (A)]
The thermoplastic resin (A) of the present invention is preferably a polyester resin or a polyolefin resin. When the base material layer contains a polyester resin or a polyolefin resin, the moisture and heat resistance of this film is improved.

Specific examples of the polyester resin include poly (ethylene glycol) terephthalic acid ester, poly (ethylene glycol) isophthalic acid ester, poly (ethylene glycol) succinic acid ester, poly (ethylene glycol) oxalic acid ester, and poly (ethylene glycol) adipine. Examples thereof include acid esters, poly (butanediol) terephthalic acid esters, poly (hexanediol) terephthalic acid esters, poly (1,4-cyclohexanedimethanol) terephthalic acid esters, and thermoplastic polyester resins typified by copolymers thereof. Be done. These polyester resins may be used alone or in combination of two or more. It should be noted that these copolymers referred to here mean that in each polymer, components other than the constituent components of each polymer are copolymerized, and the same applies to the following. The copolymerization may be graft polymerization or the like.
Among the above, poly (ethylene glycol) terephthalic acid ester is preferable from the viewpoint that the stickiness and tackiness of the film can be reduced, and the interlayer adhesion with the sealant layer and the heat resistance are excellent.

Specific examples of the polyolefin resin include polyethylene, polypropylene, polymethylpentene, and these copolymers represented by poly (ethylene-vinyl acetate) copolymers and maleic acid-modified polypropylene. These polyolefin resins can be used alone or in combination of two or more.
Among the above, polypropylene is preferable because it can reduce the stickiness and tackiness of the film, and is excellent in interlayer adhesion with the sealant layer and heat resistance.

The base material layer may be a single layer or a multilayer layer. Even in the case of a plurality of layers, it is preferable that each layer contains a thermoplastic resin as a main component, and it is preferable to use a polyolefin resin or a polyester resin as the thermoplastic resin in each layer.
In the base material layer, a polyolefin resin and a polyester resin may be used in combination. For example, the multilayer base material layer may have both a layer containing a polyolefin resin as a main component and a layer containing a polyester resin as a main component.

The base material layer of the present invention may contain various additives such as a plasticizer and a curing agent in addition to the thermoplastic resin (A).
Further, the base material layer may be a non-stretched film, or may be a uniaxially stretched or a biaxially stretched film.

[thickness]
The thickness of the base material layer is preferably 5 μm or more and 50 μm or less, more preferably 7 μm or more and 40 μm or less, and further preferably 8 μm or more and 30 μm or less.
When the thickness of the base material layer is 5 μm or more, the transportability and handleability at the time of thermal laminating are good. On the other hand, when the thickness is 50 μm or less, the transparency of this film is good.

2. 2. Sealant layer The sealant layer in the present invention comprises a resin composition containing a cyclic ether group-containing thermoplastic elastomer (B) as a main component.
Since the sealant layer contains the cyclic ether group-containing thermoplastic elastomer (B), the ionic group and the cyclic ether group-containing thermoplastic of the liquid toner component when the printed surface formed by the liquid toner comes into contact with the sealant layer. Since the elastomer (B) reacts, the adhesiveness between the sealant layer and the printed matter is improved, and the moisture and heat resistance is improved.
In addition, general thermoplastic resins rapidly soften when the flow start temperature is exceeded, but thermoplastic elastomers exhibit viscoelastic behavior with a wide rubber-like flat area after softening, so that thermal lamination is possible but they do not flow. Wide temperature range. Therefore, when the sealant layer contains the cyclic ether group-containing thermoplastic elastomer (B), the thermal laminating suitability and heat resistance are also improved.

[Resin composition]
The content of the cyclic ether group-containing thermoplastic elastomer (B) in the resin composition constituting the sealant layer is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 95% by mass or less, 70. More preferably, it is by mass or more and 90% by mass or less.
When the content of the cyclic ether group-containing thermoplastic elastomer (B) is 50% by mass or more, the moisture resistance and heat resistance are good. On the other hand, when the content is 100% by mass or less, the winding property of this film is good.

The flow start temperature of the resin composition of the present invention is 80 ° C. or higher and 105 ° C. or lower, preferably 83 ° C. or higher and 102 ° C. or lower, and more preferably 85 ° C. or higher and 100 ° C. or lower.
When the flow start temperature is 80 ° C. or higher, the moisture resistance and heat resistance are good. On the other hand, when the flow start temperature is 105 ° C. or lower, the thermal laminating suitability is good.
The flow start temperature of the present invention is measured by the method described in Examples. Further, the flow start temperature of the resin composition can be adjusted by appropriately selecting the type of the cyclic ether group-containing thermoplastic elastomer (B).

[Cyclic ether group-containing thermoplastic elastomer (B)]
The cyclic ether group-containing thermoplastic elastomer (B) of the present invention preferably has at least one of an epoxy group and an oxetane group as the cyclic ether group, and more preferably has an epoxy group.
By having a highly reactive cyclic ether group such as an epoxy group or an oxetane group, the reactivity of the liquid toner component with the ionic group is improved, and the moisture resistance and heat resistance can be improved.

When the cyclic ether group-containing thermoplastic elastomer (B) has an epoxy group, the epoxy equivalent thereof is preferably 500 g / eq or more and 3000 g / eq or less, more preferably 550 g / eq or more and 2700 g / eq or less, and 600 g / eq or more and 2500 g. It is more preferably / eq or less.
When the epoxy equivalent is 500 g / eq or more, the thermal laminating suitability is good. On the other hand, when the epoxy equivalent is 3000 g / eq or less, the moisture and heat resistance becomes good.
The epoxy equivalent of the present invention is measured according to the potentiometric titration method of JIS K7236: 2009.

The cyclic ether group-containing thermoplastic elastomer (B) is preferably a cyclic ether-modified product of the conjugated diene-based polymer.
Examples of the conjugated diene-based polymer include at least one of butadiene, isoprene and chloroprene, or a copolymer of acrylonitrile and butadiene and at least one of styrene and olefin, or a hydrogenated product thereof. .. These may be used alone or in combination of two or more.
The conjugated diene-based polymer is not particularly limited, but for example, a block copolymer may be used. Among the above, a styrene-butadiene copolymer is preferable from the viewpoint of availability, heat resistance and film forming property. That is, the cyclic ether group-containing thermoplastic elastomer (B) is preferably a cyclic ether-modified product of a styrene-butadiene copolymer, and more preferably an epoxidized styrene-butadiene copolymer. The styrene-butadiene copolymer may be, for example, a block copolymer of styrene and butadiene.

It is known that the cyclic ether group-containing thermoplastic elastomer (B) can be obtained by treating the carbon-carbon double bond in the precursor thermoplastic elastomer with a peroxide such as an organic peracid or hydrogen peroxide. Has been done. On the other hand, it can also be obtained as a commercial product as "Epofriend (Daicel)".

The resin composition constituting the sealant layer of the present invention has the purpose of improving the reactivity, transparency, antiblocking property, and gelation of the sealant layer as components other than the cyclic ether group-containing thermoplastic elastomer (B). It may contain a reaction aid, other resins, fillers, antioxidants and the like.

[thickness]
The thickness of the sealant layer is preferably 1 μm or more and 30 μm or less, more preferably 2 μm or more and 25 μm or less, and further preferably 3 μm or more and 20 μm or less.
When the thickness of the sealant layer is 1 μm or more, the thermal laminating suitability of this film is good. On the other hand, when the thickness is 30 μm or less, the transparency of this film is good.

3. 3. Release layer This film may have a release layer on the side of the sealant layer opposite to the surface facing the base material layer. By having the release layer, it is possible to prevent process troubles in winding and contamination of foreign substances. The release layer is preferably peeled off when the film is thermally laminated with the printed matter.

The release layer is not particularly limited as long as it has releasability with the sealant layer, and for example, various types such as a fluororesin film, a polyester film coated with a release agent, and a polyolefin film coated with a release agent. A release film can be mentioned. When using a release film coated with a release agent, it is advisable to bring the release agent-applied surface into contact with the sealant layer.

The thickness of the release layer is preferably 10 μm or more and 100 μm or less, more preferably 15 μm or more and 80 μm or less, and further preferably 20 μm or more and 60 μm or less.
When the thickness of the release layer is 10 μm or more and 100 μm or less, it can be easily removed during thermal laminating with a printed matter.

4. Method for Producing the Present Film Hereinafter, an example of the method for producing the printed surface protective film in the present invention will be described, but the present invention is not limited to the printed surface protective film produced by such a manufacturing method.

This film can be obtained, for example, by putting the resin composition constituting the sealant layer into an extruder and extruding and laminating it on the film to be the base material layer from the T-die extrusion base.
The gap of the T-die to be used is determined by the final required film thickness, stretching conditions, draft ratio, various conditions, etc., but is generally about 0.1 to 3.0 mm, preferably 0.5. It is about 1.0 mm. If it is 0.1 mm or more, it is preferable from the viewpoint of production speed, and if it is 3.0 mm or less, the draft rate does not become too large, so it is preferable from the viewpoint of production stability. Further, from the viewpoint of interlayer adhesion, it is preferable that at least the surface on the side where the sealant layer is laminated is previously corona-treated for the film to be the base material layer.

In the extrusion laminating, the extrusion processing temperature is appropriately adjusted depending on the flow characteristics and moldability of the resin, but is generally preferably 190 to 350 ° C, more preferably 200 to 330 ° C, still more preferably 220 to 300 ° C. When the temperature is 190 ° C. or higher, the viscosity of the molten resin is sufficiently low, the moldability is excellent, and the productivity is improved, which is preferable. On the other hand, by setting the temperature to 350 ° C. or lower, it is possible to suppress the generation of gel due to the deterioration of the resin.

In extrusion laminating, a release film can be introduced for the purpose of preventing sticking and blocking of the sealant layer. More specifically, at the time of extrusion laminating, a method of extruding a sealant layer from a T-die extrusion base onto a film to be a base material layer, placing a release film on the sealant layer, and integrating them with a press roll can be mentioned. .. By this method, troubles at the time of turning can be reduced, and foreign matter can be prevented from adhering. The release film may be a release layer in this film.
The press roll temperature and pressure can be appropriately selected depending on the thickness of the sealant layer in the target printed surface protective film. Specifically, by increasing the temperature and pressure, a thinner sealant layer can be obtained and the production speed can be improved.

<Multilayer>
In the present invention, the print protective film may be used by being laminated on the print layer. The print protective film is laminated on the print layer by thermal laminating. At this time, the print protective film may have the sealant layer facing the print layer.
Since the printed surface protective film of the present invention is excellent in heat laminating suitability, it can be easily formed into a multilayer body by heat laminating it on a printed matter having a printed layer. The multilayer body includes the print protective film and the print layer. That is, the multilayer body has a base material layer, a laminate layer, and a printing layer in this order. The printed layer is usually formed on the surface of the printed matter, and therefore the multilayer may have the printed matter having the printed layer formed on the surface.

In this film, the cyclic ether group-containing thermoplastic elastomer (B) contained in the sealant layer reacts with the liquid toner component to improve the moisture resistance and heat resistance. Therefore, when the printing layer is formed by the liquid toner, the present film is formed. Can be preferably used. The print layer may be formed, for example, by printing a liquid toner with a known printing machine and appropriately drying it.
The liquid toner preferably contains a polymer having an ionic group that can react with the cyclic ether group, and more preferably contains a carboxyl group-containing polymer.
When the liquid toner contains a carboxyl group-containing polymer, this film can be more preferably used because it has high reactivity with the cyclic ether group-containing thermoplastic elastomer (B).

The printed matter in the present invention is not particularly limited and may be any of paper-like matter, film-like matter, cloth-like matter and the like, and it is preferable that a print layer is formed on the surface thereof. The printed layer may be formed on a primer layer provided on the surface of the printed matter. The film-like material may be composed of a resin film alone or a laminated film having two or more layers including the resin film.

The multilayer body of the present invention may be used as a packaging body for packaging various articles. For example, as described above, a multilayer body in which a print protective film is laminated on the surface of a printed matter may be used as a packaging body. Since the multilayer body of the present invention has good moisture and heat resistance, it has excellent retort suitability and can be suitably used as a packaging film. The packaging film is a printed matter obtained from the above-mentioned film-like material. Further, it is more preferable that a package such as a packaging film is used for retort pouch.

The packaged article of the present invention is obtained by packaging various articles such as beverages, foods, daily necessities, or containers for storing various articles by the above-mentioned packaging body. The mode of packaging is not particularly limited, and various articles may be stored inside a bag-shaped or container-shaped package, or a part or all of the container for storing the articles or articles by the package. May be wrapped.

In the present invention, when expressed as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, it means "X or more and Y or less", and "preferably larger than X" and "preferably Y". Includes the meaning of "smaller".
Further, in the present invention, when expressed as "X or more" (X is an arbitrary number), it includes the meaning of "preferably larger than X" unless otherwise specified, and "Y or less" (Y is an arbitrary number). ) Includes the meaning of "preferably smaller than Y" unless otherwise specified.

Hereinafter, the present invention will be described in more detail with reference to Examples and Production Examples. However, the present invention is not limited to the examples and manufacturing examples described later, and various modifications can be made without departing from the gist of the present invention.

<Measurement and evaluation method>
(1) Thickness The thickness of the base material layer, the release layer and the printed surface protective film was unspecifiedly measured at 5 points with a 1/1000 mm dial gauge and determined by the average value.
The thickness of the sealant layer was calculated by subtracting the thickness of the base material layer and the release layer from the thickness of the printed surface protective film.

(2) Flow start temperature The flow start temperature of the resin composition constituting the sealant layer was raised at a rate of 3 ° C./min using a high-grade flow tester "CFT-500D" manufactured by Shimadzu Corporation. The process from the solid to the flow region of the test piece through the rubber-like elastic region was continuously measured, and the temperature at which the test piece flowed out from the nozzle was determined. The load was 40 kg / cm ² , and the nozzle was 1 mmφ × 2 mmL.

(3) Heat Laminating Suitability For the multilayer film after heat laminating, the peel strength between the sealant layer of this film and the printed matter sample was measured by the following method, and the heat laminating suitability was evaluated according to the following evaluation criteria.
○ (good): Peeling strength is 2N / 15mm or more × (pore): Peeling strength is less than 2N / 15mm

[Measurement of peel strength]
In accordance with JIS Z0237, the peel strength between the present film and the printed matter sample was measured for the multilayer film after thermal laminating. First, as a sample, a printed matter sample on which this film is heat-laminated is cut out into a width of 50 mm and a length of 150 mm, and cellophane tape (manufactured by Nichiban Co., Ltd., JIS Z1522) is attached in the vertical direction on the surface of the sample. It was folded back at 90 ° so as to overlap and peeled off by 25 mm from the sample. Next, fix one end of the sample that was peeled off to the lower chuck of the tensile tester (Intesco IM-20ST), fix the tape to the upper chuck, and increase the peel strength at a test speed of 300 mm / min. It was measured. After the measurement, the first measured value of 25 mm length was ignored, and the peeled strength measured value of 50 mm length peeled from the test piece was averaged and used as the peel strength. If the film is not peeled off and only the tape is peeled off, the peeling strength of the film is considered to be higher than the peeling strength of the tape alone.

(4) Moisture heat resistance (retort resistance)
The printed matter sample to which this film was heat-laminated was treated with a pressure cooker tester (manufactured by Espec: EHS-411M) in high-pressure steam set at 120 ° C. for 0.5 hours, and the appearance after the treatment was performed. Was evaluated according to the following criteria.
◯ (good): There is no peeling on the entire surface of the film.
X (poor): Peeling has occurred in a part.

<Material>
[Base layer]
A-1: Corona-treated biaxially stretched polyester film (thickness 12 μm, product name “Diafoil H600C”, manufactured by Mitsubishi Chemical Corporation)
[Sealant layer]
B-1: Epoxy styrene-butadiene elastomer (product name "Epofriend AT501", manufactured by Daicel, epoxy equivalent: 1100 g / eq)
B-2: Epoxy styrene-butadiene elastomer (product name "Epofriend CT310", manufactured by Daicel, epoxy equivalent: 2100 g / eq)
B-3: Ethylene-glycidyl methacrylate-based resin (product name "LOTADER AX8900", manufactured by Tokyo Zairyo Co., Ltd., epoxy equivalent: 1800 g / eq)
B-4: Ethylene-glycidyl methacrylate-based resin (product name "LOTADER AX8840", manufactured by Tokyo Zairyo Co., Ltd., epoxy equivalent: 1800 g / eq)
B-5: Maleic anhydride-modified styrene-butadiene elastomer (product name: "Toughprene 912", manufactured by Asahi Kasei Corporation)
B-6: Epoxy resin (Product name: "YX7700", manufactured by Mitsubishi Chemical Corporation)
[Release layer]
C-1: Release polyester film (thickness 38 μm, product name “Diafoil MRF-38”, manufactured by Mitsubishi Chemical Corporation)

<Example 1>
The material B-1 of the sealant layer is hot-melted at 230 ° C., extruded from the T die, cast between the base material layer A-1 and the release layer C-1, and the metal roll is set at 230 ° C. By roll pressing between the and rubber rolls at a linear speed of 0.03 m / min, a printed surface protective film having a total thickness of 70 μm was obtained.
The release layer C-1 of the obtained print surface protective film was peeled off, the sealant layer and the print surface of the printed matter sample were opposed to each other, and the speed between the heating roll and the rubber roll set at 110 ° C. was 0.1 m / min. The multilayer film of Example 1 was obtained by performing thermal laminating by passing it through with a linear pressure of 5 MPa · cm.

[Preparation of printed matter sample]
Nylon film (product name: "Harden N1200", manufactured by Toyobo Co., Ltd., thickness 15 μm) and unstretched polypropylene film (product name: "FRTK-G", manufactured by Futamura Chemical Co., Ltd., thickness 50 μm) are applied in this order. Laminating was performed by dry laminating to obtain a laminated film.
Urethane adhesive (product name: "Takelac A-515V / Takenate A-5", manufactured by Mitsui Chemicals, Inc.) is used for laminating by dry laminating, and the coating amount at the time of drying becomes 3.5 g / m ² . It was applied with a gravure plate. After bonding, aging was performed at 40 ° C. for 48 hours. After that, the nylon film side is corona-treated, polyethyleneimine (product name: "Epomin P1000", manufactured by Nippon Shokubai Co., Ltd.) is used as a primer, and a gravure roller is used to apply a weight of 0.15 g / m ² to the nylon film. It was applied so as to cover the entire side surface. Next, a printing layer was solidly printed on the surface coated with the primer of the laminated film using Magenta's HP Indigo electro ink using an HP Indigo 6600 digital printing machine. This gave a printed matter sample.

<Example 2>
A multilayer film of Example 2 was obtained in the same manner as in Example 1 except that the material of the sealant layer was changed to B-2.

<Comparative Example 1>
The multilayer film of Comparative Example 1 was obtained in the same manner as in Example 1 except that the material of the sealant layer was changed to B-3 and the heating roll temperature was changed to 180 ° C.

<Comparative Example 2>
A multilayer film of Comparative Example 2 was obtained in the same manner as in Example 1 except that the material of the sealant layer was changed to B-4.

<Comparative Example 3>
A multilayer film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the material of the sealant layer was changed to B-5.

<Comparative Example 4>
The multilayer film of Comparative Example 4 was obtained in the same manner as in Example 1 except that the material of the sealant layer was changed to B-6 and the heating roll temperature was changed to 180 ° C.

In Examples 1 and 2, the sealant layer contains the cyclic ether group-containing thermoplastic elastomer (B), and the flow start temperature of the resin composition constituting the sealant layer is 80 ° C. or higher and 105 ° C. or lower. A printed surface protective film having excellent thermal lamination suitability and moisture heat resistance was obtained.
On the other hand, in Comparative Example 1, since the flow start temperature of the resin composition was too low, the film was deformed in a moist heat environment, resulting in a film having poor moist heat resistance. In Comparative Example 2, since the flow start temperature of the resin composition was too high, the adhesion to the printed matter sample was poor, and the film had poor thermal laminating suitability. In Comparative Example 3, since the elastomer constituting the sealant layer was not epoxy-modified, the reaction with the liquid toner component did not occur and the moisture resistance was insufficient. In Comparative Example 4, since the sealant layer is a general epoxy resin that is not a thermoplastic elastomer, the heat laminating suitability and the moisture heat resistance are insufficient.

Claims (13)

It has at least a substrate layer and a sealant layer,
The base material layer contains the thermoplastic resin (A) as a main component and contains.
A printed surface protective film in which the sealant layer comprises a resin composition containing a cyclic ether group-containing thermoplastic elastomer (B) as a main component, and the flow start temperature of the resin composition is 80 ° C. or higher and 105 ° C. or lower. The printed surface protective film according to claim 1, wherein the thickness of the base material layer is 5 μm or more and 50 μm or less. The printed surface protective film according to claim 1 or 2, wherein the sealant layer has a thickness of 1 μm or more and 30 μm or less. The printed surface protective film according to any one of claims 1 to 3, wherein the thermoplastic resin (A) is at least one selected from the group consisting of polyester resin and polyolefin resin. The printed surface protective film according to any one of claims 1 to 4, wherein the cyclic ether group-containing thermoplastic elastomer (B) contains an epoxy group and has an epoxy equivalent of 500 g / eq or more and 3000 g / eq or less. The printed surface protective film according to any one of claims 1 to 5, wherein the cyclic ether group-containing thermoplastic elastomer (B) is a cyclic ether-modified product of a conjugated diene-based polymer. The conjugated diene-based polymer comprises at least one of butadiene, isoprene, and chloroprene, or a copolymer of acrylonitrile and butadiene rubber with at least one of styrene and olefin, and a hydrogenated product thereof. The printed surface protective film according to claim 6, which is at least one selected from the group. The printed surface protective film according to any one of claims 1 to 7, which has a release layer on the side of the sealant layer opposite to the surface facing the base material layer. A multilayer body comprising the print surface protective film according to any one of claims 1 to 8 and a print layer, and the print surface protective film is thermally laminated on the print layer. The multilayer body according to claim 9, wherein the printing layer is formed of liquid toner. The multilayer body according to claim 10, wherein the liquid toner contains a carboxyl group-containing polymer. A package body comprising the multilayer body according to any one of claims 9 to 11. A packaged article packaged by the package according to claim 12.