JP2013159039A - Marking sheet, and method for producing marking sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a marking sheet excellent in antiweatherability, antifouling property, and adhesion between a fluororesin layer and a main film layer, and to provide a method for producing the marking sheet.SOLUTION: A marking sheet A includes a base material 4 comprising a main film layer 3 and a fluororesin layer 2, and an adhesive layer 5 layered on a main film layer 3 side of the base material 4 directly or through one layer or more. The fluororesin layer 2 has a cross-linked structure formed by cross-liking reaction between a fluororesin having a cross-link functional group and an isocyanate cross-linking agent (A). In addition, the adhesion between the main film layer 3 and the fluororesin layer 2 is Class 0 in an adhesion test measured according to JISK5600-5-6:1999. A method for producing the marking sheet is provided.

Description

  The present invention relates to a marking sheet useful for outdoor use and a method for producing the marking sheet.

A marking sheet used for an outdoor signboard or the like is required to have excellent weather resistance and antifouling property. For this reason, conventionally, the weather resistance and the antifouling property have been improved by providing a fluororesin layer on the surface of the main film layer made of vinyl chloride resin or the like.
This fluororesin layer is usually formed by applying a liquid (fluororesin-containing liquid) in which a fluororesin is dissolved or dispersed in a solvent onto the main film layer and drying the obtained coating film.
However, when a marking sheet is produced, if a fluororesin-containing liquid is directly applied to the surface of the main membrane layer, the solvent penetrates into the main membrane layer and remains in the interior, which easily causes problems such as deterioration of the marking sheet. There was a problem.

As a method for solving this problem, there is known a method in which a fluororesin layer is first formed on a process sheet, and then a main film layer is formed on the fluororesin layer by a casting method (Patent Document 1). .
However, when a marking sheet is produced by this method, the adhesion between the fluororesin layer and the main film layer may be inferior.

JP-A-7-68716

  The present invention has been made in view of such circumstances, and is a marking sheet excellent in weather resistance and antifouling properties, and excellent in adhesion between the fluororesin layer and the main film layer, and the marking It aims at providing the manufacturing method of the marking sheet which can obtain a sheet | seat efficiently.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors applied a fluororesin-containing liquid containing a blocked isocyanate-based crosslinking agent and a fluororesin having a crosslinkable functional group on a process sheet, After the obtained coating film was dried at a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent to obtain a dried coating film, the main film layer-constituting resin-containing liquid was applied on the obtained dried coating film, and then The crosslinking coating reaction between the fluororesin and the isocyanate crosslinking agent is performed by heating the dried coating film and the coating film of the main film layer constituting resin-containing liquid to a block dissociation temperature of the blocked isocyanate crosslinking agent to 200 ° C. or less. The inventors have found that a marking sheet having desired properties can be efficiently obtained by simultaneously drying the coating film of the main film layer constituting resin-containing liquid, and have completed the present invention.

Thus, according to the present invention, the following marking sheets (1) to (3) and the manufacturing method of the marking sheet (4) are provided.
(1) A marking sheet having a base material composed of a main film layer and a fluororesin layer, and an adhesive layer laminated directly or via one or more layers on the main film layer side of the base material. And
The fluororesin layer has a cross-linked structure formed by a cross-linking reaction between a fluororesin having a crosslinkable functional group and an isocyanate-based cross-linking agent (A), and
A marking sheet, wherein the adhesion between the main film layer and the fluororesin layer is classified as 0 in an adhesion test measured according to JIS K5600-5-6: 1999.
(2) The marking sheet according to (1), wherein the main film layer contains a vinyl chloride resin.

(3) The marking sheet according to (1) or (2), wherein the substrate is obtained by a production method including the following steps I to III.
Step I: A fluororesin-containing liquid containing a blocked isocyanate-based cross-linking agent that generates the isocyanate-based cross-linking agent (A) by dissociating a protective group on the step sheet, and a fluororesin having a cross-linkable functional group The coating film obtained is dried at a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent. Step II: On the dried coating film obtained in Step I, the main film layer constituting resin is contained. Step III of coating the solution: The dried coating film of the fluororesin-containing liquid obtained in Step I, and the coating film of the main film layer-constituting resin-containing liquid obtained in Step II are used as the blocked isocyanate crosslinking agent. (4) The manufacturing method of the marking sheet in any one of (1)-(3) including the following process I-IV.
Step I: A fluororesin-containing liquid containing a blocked isocyanate-based cross-linking agent that generates the isocyanate-based cross-linking agent (A) by dissociating a protective group on the step sheet, and a fluororesin having a cross-linkable functional group The coating film obtained is dried at a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent. Step II: On the dried coating film obtained in Step I, the main film layer constituting resin is contained. Step III of coating the solution: The dried coating film of the fluororesin-containing liquid obtained in Step I, and the coating film of the main film layer-constituting resin-containing liquid obtained in Step II are used as the blocked isocyanate crosslinking agent. Step IV: Forming a substrate composed of a main film layer and a fluororesin layer by heating to a block dissociation temperature of 200 ° C. or less, directly on the main film layer side of the substrate obtained in Step III Via one or more layers, laminating a pressure-sensitive adhesive layer

The marking sheet of the present invention is a marking sheet that is excellent in weather resistance and antifouling properties and excellent in adhesion between the fluororesin layer and the main film layer. Since the marking sheet of the present invention has such characteristics, it is preferably used when an outdoor signboard or the like is produced.
According to the marking sheet manufacturing method of the present invention, the marking sheet can be efficiently manufactured.

It is manufacturing process sectional drawing of the marking sheet of this invention.

  Hereinafter, the present invention will be described in detail by dividing it into 1) a marking sheet and 2) a method for producing a marking sheet.

1) Marking sheet The marking sheet of the present invention is a base material composed of a main film layer and a fluororesin layer, and an adhesive layered directly or via one or more layers on the main film layer side of the base material. A marking sheet having an agent layer, wherein the fluororesin layer has a crosslinked structure formed by a crosslinking reaction between a fluororesin having a crosslinkable functional group and an isocyanate-based crosslinking agent (A), and The adhesion between the main film layer and the fluororesin layer is classified as 0 in an adhesion test measured according to JIS K5600-5-6: 1999.

(Base material)
The base material of the marking sheet of the present invention is composed of a main film layer and a fluororesin layer, and further, by a cross-linking reaction between a fluororesin having a crosslinkable functional group and an isocyanate cross-linking agent (A) in the fluororesin layer. It has a formed crosslinked structure.

The main film layer is a layer containing the same resin component as the base film of the conventional marking sheet.
The resin constituting the main film layer (hereinafter sometimes abbreviated as “main film layer constituting resin”) can be appropriately selected in consideration of the strength, flexibility, appearance, etc. of the marking sheet.
The number average degree of polymerization of the main film layer constituting resin is not particularly limited, but is preferably about 800 to 2500.

  Examples of the main film layer-constituting resin include vinyl chloride resins, olefin resins, urethane resins, and acrylic resins. Among these, a vinyl chloride resin is preferable because a marking sheet having excellent weather resistance can be obtained.

The vinyl chloride resin is a polymer having repeating units derived from vinyl chloride.
Examples of the vinyl chloride resin include polyvinyl chloride; copolymers mainly composed of vinyl chloride such as ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer, vinyl chloride-halogenated olefin copolymer; etc. Is mentioned. In the copolymer mainly composed of vinyl chloride, the amount of vinyl chloride-derived repeating units is preferably 50 mol% or more, more preferably 70 mol% or more, based on all repeating units.

A vinyl chloride resin can be used individually by 1 type or in combination of 2 or more types.
The vinyl chloride resin can be used in combination with other resins. Other resins are preferably resins compatible with vinyl chloride resins. Examples of such resins include polyester resins, epoxy resins, acrylic resins, vinyl acetate resins, urethane resins, acrylonitrile-styrene-butadiene copolymers, and partially saponified polyvinyl alcohol.
When a vinyl chloride resin and another resin are used in combination, the compounding amount of the other resin is usually 1 to 50 parts by mass, preferably 5 to 30 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. is there.

  The main film layer may contain an additive in addition to the main film layer constituting resin. Additives used include plasticizers; stabilizers such as lead salt stabilizers, metal soap stabilizers, organotin stabilizers; antioxidants; UV absorbers; light stabilizers; flexibility imparting agents; An antistatic agent, a foaming agent, a lubricant, a filler, a colorant, and the like. When it contains an additive, the compounding quantity of an additive is 1-50 mass parts normally with respect to 100 mass parts of vinyl chloride-type resins.

As will be described later, the main film layer can be formed by preparing a main film layer-constituting resin-containing liquid containing a main film layer-constituting resin or additive, and using a casting method using this.
The thickness of the main film layer is usually 25 to 300 μm.

The fluororesin layer plays a role of improving the weather resistance and antifouling property of the marking sheet by being disposed on the surface of the main film layer.
A fluororesin layer is a layer formed by the crosslinking reaction of the fluororesin which has a crosslinkable functional group, and an isocyanate type crosslinking agent (A).

  The crosslinkable functional group is a group that can react with an isocyanate group to form a crosslinked structure, and examples thereof include a hydroxyl group, a carboxyl group, and an amino group. Among these, a hydroxyl group is preferable because of excellent reactivity.

  As a fluororesin having a crosslinkable functional group (hereinafter sometimes abbreviated as “fluororesin”), the molecule has a repeating unit derived from a fluorine-containing monomer and has a crosslinkable functional group. The polymer is not particularly limited as long as it has a polymer, and examples thereof include a copolymer of a fluorine-containing monomer and a monomer having a crosslinkable functional group. The copolymer may be a block copolymer or a random copolymer.

  Fluorine-containing monomers include trifluoroethylene, tetrafluoroethylene (ethylene trifluoride), 1-hydropentafluoropropylene, 2-hydropentafluoropropylene, hexafluoropropylene, chlorotrifluoroethylene, 3, 3, 3 -Trifluoropropylene, vinylidene fluoride, vinyl fluoride, perfluoroalkyl vinyl ether and the like.

  Examples of the monomer having a crosslinkable functional group include a hydroxyl group-containing acrylic monomer and a carboxyl group-containing acrylic monomer.

Examples of hydroxyl-containing acrylic monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl. Examples thereof include hydroxyalkyl (meth) acrylates such as (meth) acrylate and 4-hydroxybutyl (meth) acrylate.
Examples of the carboxyl group-containing acrylic monomer include (meth) acrylic acid.
In the present specification, “(meth) acrylate” means “acrylate or methacrylate”, and the same applies to “(meth) acrylic acid” and the like.

  The fluororesin may further have a repeating unit derived from another monomer.

  Other monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Examples include alkyl (meth) acrylates such as decyl (meth) acrylate; hydroxyalkyl vinyl ether; hydroxyalkyl allyl ether; hydroxycarboxylic acid vinyl ester; hydroxycarboxylic acid allyl ester; N-hydroxyalkyl (meth) acrylamide.

  The content of the repeating unit derived from the fluorine-containing monomer in the fluororesin is preferably from 10 to 60 mol%, more preferably from 20 to 50 mol% in all repeating units. Moreover, 5-50 mol% is preferable in all the repeating units, and, as for content of the repeating unit derived from the monomer which has a crosslinkable functional group, 10-40 mol% is more preferable.

Although the weight average molecular weight of a fluororesin is not specifically limited, Usually, 5000-500000, Preferably it is 10000-250,000.
The weight average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography (GPC) method.
A fluororesin can be used individually by 1 type or in combination of 2 or more types.

Although the hydroxyl value (mgKOH / g) of a fluororesin is not specifically limited, Preferably it is 200 or less, More preferably, it is more than 0 and 200 or less, More preferably, it is 20-80. The acid value (mgKOH / g) of the fluororesin is not particularly limited, but is preferably 10 to 200, more preferably 50 to 150, and still more preferably 80 to 120.
When the hydroxyl value and the acid value are in the above ranges, cohesive failure of the fluororesin layer is suppressed when the process sheet is peeled, and a marking sheet having excellent weather resistance and solvent resistance can be obtained. The hydroxyl value and acid value are values measured by the neutralization titration method described in JIS K0070: 1992.

Further, the fluororesin can be used in combination with other resins. As other resin, a resin compatible with a fluororesin having a crosslinkable functional group is preferable. Examples thereof include polyester resin, epoxy resin, acrylic resin, vinyl acetate resin, urethane resin, acrylonitrile-styrene-butadiene copolymer, and partially saponified polyvinyl alcohol.
When using together fluororesin and other resin, the compounding quantity of other resin is 1-50 mass parts normally with respect to 100 mass parts of fluororesins, Preferably, it is 5-30 mass parts.

The fluororesin layer has a cross-linked structure formed by a cross-linking reaction between the fluororesin and the isocyanate cross-linking agent (A) in the layer.
As such a crosslinked structure, a chemical bond (urethane bond: —O—C (═O) NH—) formed by a reaction between the isocyanate group of the isocyanate-based crosslinking agent (A) and the hydroxyl group of the fluororesin, isocyanate-based crosslinking. Chemical bond (—C (═O) O—C (═O) —NH—) formed by the reaction of the isocyanate group of the agent (A) and the carboxyl group of the fluororesin, of the isocyanate crosslinking agent (A) Examples thereof include a chemical bond (—NH—C (═O) —NH—) formed by reacting an isocyanate group with an amino group of a fluororesin. Among these, a urethane bond (—O—C (═O) NH—) is preferable.

The isocyanate-based crosslinking agent (A) is composed of a polyisocyanate compound (a compound having two or more isocyanate groups in one molecule).
As an isocyanate type crosslinking agent (A), an aromatic polyisocyanate compound, an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, etc. are mentioned.
These isocyanate type crosslinking agents (A) can be used singly or in combination of two or more.

  As aromatic polyisocyanate compounds, 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), tolidine diisocyanate, naphthalene-1,5-diisocyanate, tetramethylene xylylene diisocyanate, polymethylene poly Phenyl polyisocyanate; and derivatives thereof. Examples of these derivatives include modified products such as isocyanurate, biuret and uretdione.

  Aliphatic polyisocyanate compounds include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HMDI), heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3-methyl. -1,5-pentane diisocyanate, and derivatives thereof.

  As the alicyclic polyisocyanate compound, 3,3,5-trimethyl-1-isocyanato-5-isocyanatomethylcyclohexane, 1,6-bisisocyanatomethylcyclohexane, bis (4,4′isocyanatocyclohexyl) methane, And derivatives thereof.

The marking sheet of the present invention is excellent in adhesion between the fluororesin layer and the main film layer, but in order to obtain this characteristic, it is important to appropriately control the crosslinking reaction.
In order for the marking sheet of the present invention to have preferable physical properties, as will be described later, as an isocyanate-based crosslinking agent (A), a blocked isocyanate in which a protecting group is dissociated by heating to produce an isocyanate-based crosslinking agent (A). It is preferably used in the form of a system crosslinking agent.

  The blocked isocyanate-based crosslinking agent is composed of blocked isocyanate, and the protective group is dissociated by heating to a block dissociation temperature or higher to produce an active isocyanate-based crosslinking agent (A).

The block dissociation temperature is a temperature at which the protective group of the blocked isocyanate is dissociated to generate an active isocyanate-based crosslinking agent (A). This temperature can be obtained as the peak temperature of the DTA curve when differential thermal-thermogravimetric simultaneous measurement (TG / DTA) is performed up to 300 ° C. at a rate of temperature increase of 10 ° C./min in an N ₂ gas atmosphere. it can.

The block isocyanate crosslinking agent used in the present invention preferably has a block dissociation temperature of 90 to 150 ° C, more preferably 100 to 140 ° C. When the block dissociation temperature is within this temperature range, the fluororesin layer can be dried without being cross-linked, and at the same time as the main membrane layer is dried, cross-linking can be easily formed in the fluororesin layer. .
In particular, when the block dissociation temperature exceeds 200 ° C., the film does not have sufficient mechanical strength because the film is not sufficiently crosslinked unless a high temperature is applied for a long time.

  The blocked isocyanate crosslinking agent is an addition reaction product of a polyisocyanate compound and a blocking agent, and can be produced and obtained by a conventionally known method.

  As the blocking agent to be used, those having one or more active hydrogen atoms are preferable. For example, phenols such as phenol, thiophenol, cresol, and resorcinol; aromatic secondary amines such as diphenylamine and xylidine; cyclic amines such as pyrazole and dimethylpyrazole; phthalimides; lactams such as caprolactam and valerolactam Oximes such as acetoxime, methyl ethyl ketoxime and cyclohexanone oxime; acidic sodium sulfite; and the like.

  Moreover, a commercial item can also be used as it is as a block isocyanate type crosslinking agent. Examples of commercially available products include DURANATE series from Asahi Kasei Chemicals, Karenz MOI-BM, BP from Showa Denko.

  The amount of the isocyanate-based crosslinking agent (A) and the blocked isocyanate crosslinking agent used is such that the ratio of isocyanate group to the number of crosslinkable functional groups of the fluororesin at the time of block dissociation (isocyanate group: crosslinkable functional group) is 0.15: 1 to 2.5: 1 is preferable, and 0.25: 1 to 1.5: 1 is more preferable. In particular, when the fluororesin has a hydroxyl group as a crosslinkable functional group, including the case of having both a hydroxyl group and a carboxyl group), the ratio of the number of isocyanate groups to the hydroxyl groups of the fluororesin (isocyanate group: hydroxyl group) is 0.3. : 1 to 5: 1 is preferable, and 0.5: 1 to 3: 1 is more preferable.

As will be described later, the fluororesin layer can be formed by a known method using a fluororesin-containing liquid containing a fluororesin and a blocked isocyanate-based crosslinking agent.
The thickness of the obtained fluororesin layer is usually 0.5 to 20 μm.

(Adhesive layer)
The pressure-sensitive adhesive layer of the marking sheet of the present invention is the same as a pressure-sensitive adhesive layer known as a pressure-sensitive adhesive layer for outdoor marking sheets.
The pressure-sensitive adhesive layer can be formed by a known method using a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, or a polyester pressure-sensitive adhesive.
Among these, from the viewpoint of weather resistance, cost, etc., it is preferable to use an acrylic pressure-sensitive adhesive.

The thickness of the pressure-sensitive adhesive layer is usually 15 to 50 μm, preferably 20 to 40 μm.
The pressure-sensitive adhesive layer may be formed by directly applying a pressure-sensitive adhesive on the main film layer of the base material. After forming the pressure-sensitive adhesive layer on the release sheet, the pressure-sensitive adhesive layer is bonded to the base material. Also good.

(Peeling sheet)
The marking sheet of the present invention may further have a release sheet that protects the pressure-sensitive adhesive layer.
As release sheet, polyester film substrate such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polyolefin film substrate such as polyethylene, polypropylene, polymethylpentene; paper such as clay coated paper, glassine paper, recycled paper Base materials; those having a release treatment on one side, such as laminated paper obtained by laminating a thermoplastic resin such as polyethylene to these paper base materials; and the like. Examples of the release treatment agent include silicone resins, long chain alkyl resins, fluorine resins, and the like.
The thickness of the release sheet is not particularly limited, and is usually 10 to 150 μm.

  When manufacturing a long marking sheet and winding it into a roll, if there is unevenness on the back side of the release sheet (the surface that has not been released), the unevenness is transferred to the fluororesin layer that contacts the release sheet. May be. In order to solve this problem, it is preferable to use a release sheet of a film base.

(Other layers)
The marking sheet of this invention may have other layers, such as a primer layer, between the main film layer and adhesive layer of a base material. By having the primer layer, the adhesion between the main film layer and the pressure-sensitive adhesive layer may be improved.

  Further, in the marking sheet of the present invention, on the surface opposite to the side where the adhesive layer of the substrate is provided, if necessary, a weather resistant layer such as an acrylic polymer type ultraviolet absorbing layer, a printing layer, a colored resin layer At least one layer selected from among the above can be provided.

  The marking sheet of the present invention has a classification 0 (the edge of the cut is completely in the adhesion test in which the adhesion between the main film layer and the fluororesin layer is measured according to JIS K5600-5-6: 1999). It is smooth and has no peeling to the eyes of any lattice.)

Since the marking sheet of the present invention has high adhesion between the main film layer and the fluororesin layer, it is classified as 0 in the adhesion test.
On the other hand, when the adhesion between the main film layer and the fluororesin layer is low, the test cannot be performed because the adhesion test does not result in classification 0 or the fluororesin layer peels off, and the test can be performed. There are things you can't do.

2. Manufacturing method of marking sheet The manufacturing method of the marking sheet of this invention produces a base material by the method including the following processes I-III, and manufactures a marking sheet using the obtained base material then ( Step IV).
Step I: A fluororesin-containing liquid containing a blocked isocyanate-based cross-linking agent that generates the isocyanate-based cross-linking agent (A) by dissociating a protective group on the step sheet, and a fluororesin having a cross-linkable functional group The coating film obtained is dried at a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent. Step II: On the dried coating film obtained in Step I, the main film layer constituting resin is contained. Step III of applying the liquid: By heating the dried coating obtained in Step I and the coating obtained in Step II to a block dissociation temperature of the block isocyanate crosslinking agent of 200 ° C. or less, Step IV for forming a base material composed of a main film layer and a fluororesin layer: A pressure-sensitive adhesive layer is directly or via one or more layers on the main film layer side of the base material obtained in Step III. Laminate A process

  Hereinafter, it will be described in detail with reference to FIG. In the description of FIG. 1, the “fluororesin layer” means “a layer obtained by applying a fluororesin-containing liquid” regardless of its dry state or cross-linked state. "Membrane layer" means "a layer obtained by applying a main membrane layer-constituting resin-containing liquid" regardless of its dry state.

(Process I)
First, as shown to Fig.1 (a), the fluororesin containing liquid containing a block isocyanate type crosslinking agent and a fluororesin is applied on a process sheet | seat (1).

The fluororesin-containing liquid is a solution or dispersion containing a blocked isocyanate crosslinking agent and a fluororesin. The fluororesin-containing liquid may contain other resins and additives.
Examples of the solvent used in the fluororesin-containing liquid include aromatic solvents such as toluene and ester solvents such as ethyl acetate.

It does not specifically limit as a process sheet (1), A well-known process sheet can be used. For example, various types of paper or a resin film made of polyethylene terephthalate, polypropylene, polyethylene or the like is subjected to a release treatment with a release agent such as silicone, polyester, acrylic, alkyd, urethane, or a synthetic resin.
The thickness of the process sheet (1) is usually 10 to 200 μm, preferably 25 to 150 μm.

  The method for coating the fluororesin-containing liquid on the process sheet (1) is not particularly limited, and a known method can be used. For example, the coating can be performed using a gravure coater, a Meyer bar, a die coater, a knife coater or the like.

  Next, as shown in FIG. 1 (b), the coating film (fluororesin layer (2a)) of the fluororesin-containing solution obtained above is dried at a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent. Thus, the fluororesin layer (2b) is formed.

When the drying temperature of the coating film is a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent, the fluororesin layer (2a) can be dried with the unreacted blocked isocyanate crosslinking agent remaining. As will be described later, as a result, the adhesion between the fluororesin layer (2) and the main film layer (3) can be enhanced by heat treatment in a later step. It is more preferable that the drying temperature is 10 ° C. or lower than the dissociation temperature.
The block dissociation temperature of the blocked isocyanate crosslinking agent is usually 90 to 150 ° C. Accordingly, preferable drying conditions are usually 80 to 120 ° C. and 30 seconds to 3 minutes.

(Step II)
Thereafter, as shown in FIG. 1C, the main film layer-constituting resin-containing liquid is applied onto the dried coating film (fluororesin layer (2b)) obtained in Step I.

The main film layer-constituting resin-containing liquid is a solution or dispersion containing the main film layer-constituting resin and, if necessary, additives.
Examples of the main film layer-constituting resin and additives include the same as those exemplified above. As the main film layer, a vinyl chloride resin is preferable.

  Examples of the solvent used for the main membrane layer-constituting resin-containing liquid include ketone solvents such as methyl isobutyl ketone, ester solvents such as butyl acetate, glycol ether solvents such as ethylene glycol monobutyl ether, and the like.

  The method for coating the main film layer-constituting resin-containing liquid on the fluororesin layer (2b) is not particularly limited, and a known method can be used. For example, the method described in Step I can be mentioned.

(Step III)
Next, as shown in FIG. 1 (d), the dried coating film of the fluororesin-containing liquid obtained in Step I [the coating of the fluororesin layer (2b) and the main membrane layer-constituting resin-containing liquid obtained in Step II is applied. The membrane (3a) is heated to a block dissociation temperature of the blocked isocyanate crosslinking agent to 200 ° C. or less.
By performing Step III, the coating film (3a) of the main film layer constituting resin-containing liquid is dried to form the main film layer (3), and at the same time, the dried coating film (2b) of the fluororesin-containing liquid is formed. The crosslinking reaction proceeds therein, and a crosslinked structure is formed by the crosslinking reaction between the fluororesin having a crosslinkable functional group and the isocyanate crosslinking agent (A).

The heating temperature in step III is preferably 150 to 200 ° C, more preferably 160 to 200 ° C. The heating time is usually 30 seconds to 3 minutes, preferably 30 seconds to 2 minutes.
Thus, the base film (4) which is excellent in the adhesiveness of two layers can be obtained by forming the main film layer (3) and the fluororesin layer (2) at the same time.

(Process IV)
Thereafter, as shown in FIG. 1 (e), a pressure-sensitive adhesive is applied to the main film layer side of the base material (4) obtained from step III and composed of the main film layer (3) and the fluororesin layer (2). Layer (5) is laminated.
For example, a pressure-sensitive adhesive sheet composed of a release layer (6) and a pressure-sensitive adhesive layer (5) obtained by applying a pressure-sensitive adhesive on the release sheet, and a main film layer (5) of the substrate (4), The laminated body of FIG.1 (e) can be obtained by bonding so that the adhesive layer (5) of an adhesive sheet may oppose.
Moreover, you may employ | adopt the method of forming an adhesive layer on the main film layer of a base material, and laminating | stacking a peeling layer on an adhesive layer depending on necessity.
About a peeling sheet and an adhesive, what was demonstrated previously can be used.

  In this case, before performing step IV, the surface of the main film layer (3) may be subjected to corona discharge treatment or primer treatment. By performing this treatment, the adhesion between the main film layer (3) and the pressure-sensitive adhesive layer (5) can be enhanced.

By the above method, the marking sheet (A) of the present invention can be produced.
Moreover, when manufacturing the marking sheet of this invention, a process sheet | seat (1) can be peeled in arbitrary steps. Therefore, the marking sheet of the present invention may be a marking sheet (B) shown in FIG.

In the method of forming the fluororesin layer on the process sheet and then forming the main film layer, the problem of poor drying is solved, but the adhesion between the fluororesin layer and the main film layer tends to be lowered.
However, by using a blocked isocyanate cross-linking agent as described above and appropriately controlling the cross-linking reaction, the problem of poor drying is solved, and at the same time, the marking sheet has excellent adhesion between the fluororesin layer and the main film layer. Can be obtained efficiently.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
The weight average molecular weight, acid value, hydroxyl value, and block dissociation temperature were measured by the methods described above.

[Example 1]
Fluororesin (using ethylene trifluoride / butyl acrylate (BA) / 2-hydroxyethyl methacrylate (HEMA) / acrylic acid (AA) / methyl methacrylate (MMA) = 30/30/15/15/10 (molar ratio) Resin, weight average molecular weight 50000, acid value 110, hydroxyl value 61, solid content 30% by mass) and 100 parts by mass of a block isocyanate crosslinking agent (manufactured by Asahi Kasei Chemicals, DURANATE SBN-70D, block dissociation temperature 110) C., hereinafter abbreviated as “crosslinking agent 1”) so that the ratio of the number of isocyanate groups in the blocked isocyanate crosslinking agent to the number of hydroxyl groups in the fluororesin (isocyanate group: hydroxyl group) is 1: 1. A fluororesin-containing liquid was prepared by mixing in ethyl acetate.

  Next, the fluororesin-containing liquid obtained above was applied onto a process sheet (polyethylene terephthalate film coated with a silicone-modified alkyd resin, thickness: 50 μm) using a knife coater, and the resulting coating film was applied at 90 ° C. And dried for 90 seconds to obtain a dried coating film (thickness: 10 μm).

  Meanwhile, 100 parts by mass of a vinyl chloride resin (PolyOne Corporation, Geon 178), 35 parts by mass of a polyester plasticizer (Daiichi Seika Kogyo Co., Ltd., Finesizer NS-4070), a metal soap stabilizer (Katsuta Chemical Industries, B-9301) 4 parts by mass and 40 parts by mass of ethylene glycol monobutyl ether as a solvent were mixed to prepare a main membrane layer constituting resin-containing liquid.

Next, the main film layer-constituting resin-containing liquid was applied on the dry paint film of the dry paint film with the process sheet using a knife coater. The resulting laminate was heated at 90 ° C. for 90 seconds and then at 190 ° C. for 30 seconds. The thickness of the main film layer after heating was 55 μm.
Thereafter, a pressure-sensitive adhesive sheet in which an adhesive layer (thickness 20 μm) mainly composed of an acrylic solvent-based pressure-sensitive adhesive (manufactured by Lintec Corporation, PA-10) is formed on the release film on the main film layer formed above. Were bonded together so that the main film layer and the pressure-sensitive adhesive layer face each other, to produce a marking sheet 1 with a process sheet.

[Example 2]
A marking sheet 2 with a process sheet was produced in the same manner as in Example 1 except that the amount of the crosslinking agent was changed so that the ratio of the number of isocyanate groups to hydroxyl groups (isocyanate group: hydroxyl group) was 2: 1. .

Example 3
As a crosslinking agent, instead of the crosslinking agent 1, a blocked isocyanate crosslinking agent (manufactured by Asahi Kasei Chemicals, DURANATE TPA-B80E, block dissociation temperature 130 ° C., hereinafter abbreviated as “crosslinking agent 2”) and an isocyanate group. A marking sheet 3 with a process sheet was produced in the same manner as in Example 1 except that the ratio of the number of hydroxyl groups (isocyanate group: hydroxyl group) was 2: 1.

[Comparative Example 1]
As a crosslinking agent, instead of the crosslinking agent 1, a non-blocking isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HL, hereinafter abbreviated as “crosslinking agent 3”) is used as a ratio of the number of isocyanate groups to hydroxyl groups. A marking sheet 4 with a process sheet was produced in the same manner as in Example 1 except that (isocyanate group: hydroxyl group) was used at 2: 1.

[Comparative Example 2]
A marking sheet 5 with a process sheet was produced in the same manner as in Example 2 except that the drying temperature of the fluororesin layer was changed to 120 ° C.

[Interface when the process sheet is peeled off]
Each of the marking sheets 1 to 5 with process sheets obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was cut out in a size of 10 cm × 10 cm, and then the process sheet was peeled off.
The presence or absence of fluororesin on the release surface of the process sheet was examined by infrared absorption spectroscopy. Table 1 shows the number of detected fluororesins. When the fluororesin is detected, it can be determined that the interlayer adhesion between the fluororesin layer and the main film layer is low.

[Adhesion test]
Each of the marking sheets 1 to 3 with a process sheet obtained in Examples 1 to 3 was cut out in a size of 10 cm × 10 cm, and then the process sheet was peeled off.
Using this as a test piece, the adhesion between the fluororesin layer and the main film layer was evaluated according to JIS K5600-5-6: 1999.
The adhesion was evaluated on a 6-point scale, from the case where no peeling occurred (Category 0) to the case where the degree of peeling was large (Category 5).
In addition, the marking sheets 4 and 5 with a process sheet of Comparative Examples 1 and 2 could not be tested because the fluororesin layer was also peeled off when the process sheet was peeled off.

From Table 1, in Examples 1 to 3, as a result of using blocked isocyanate, a marking sheet having higher adhesion between the fluororesin layer and the main film layer than Comparative Example 1 was obtained.
On the other hand, the marking sheet 4 with a process sheet of Comparative Example 1 manufactured using a non-blocked isocyanate-based crosslinking agent has low adhesion between the fluororesin layer and the main film layer, and the fluororesin layer is in a stage where the process sheet is peeled off. It peeled. In addition, the marking sheet 5 with the process sheet of Comparative Example 2 manufactured by making the drying temperature of the fluororesin layer higher than the dissociation temperature of the blocked isocyanate also has low adhesion between the fluororesin layer and the main film layer, and peels off the process sheet. At the stage, the fluororesin layer was peeled off.

1 .... Process sheet 2a ... Fluororesin layer (before drying)
2b ... Fluororesin layer (after drying)
2 .... Fluororesin layer (after cross-linking)
3a ... Main membrane layer (before drying)
3. Main film layer (after drying)
4 ... Base material 5 ... Adhesive layer 6 ... Release layers A, B ... Marking sheet

Claims (4)

A marking sheet having a base material composed of a main film layer and a fluororesin layer, and an adhesive layer laminated directly or via one or more layers on the main film layer side of the base material,
The fluororesin layer has a cross-linked structure formed by a cross-linking reaction between a fluororesin having a crosslinkable functional group and an isocyanate-based cross-linking agent (A), and
A marking sheet, wherein the adhesion between the main film layer and the fluororesin layer is classified as 0 in an adhesion test measured according to JIS K5600-5-6: 1999.   The marking sheet according to claim 1, wherein the main film layer contains a vinyl chloride resin. The marking sheet according to claim 1 or 2, wherein the substrate is obtained by a production method including the following steps I to III.
Step I: A fluororesin-containing liquid containing a blocked isocyanate-based cross-linking agent that generates the isocyanate-based cross-linking agent (A) by dissociating a protective group on the step sheet, and a fluororesin having a cross-linkable functional group The coating film obtained is dried at a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent. Step II: On the dried coating film obtained in Step I, the main film layer constituting resin is contained. Step III of coating the solution: The dried coating film of the fluororesin-containing liquid obtained in Step I, and the coating film of the main film layer-constituting resin-containing liquid obtained in Step II are used as the blocked isocyanate crosslinking agent. Heating to a block dissociation temperature of no lower than 200 ° C. The manufacturing method of the marking sheet in any one of Claims 1-3 containing the following processes I-IV.
Step I: A fluororesin-containing liquid containing a blocked isocyanate-based cross-linking agent that generates the isocyanate-based cross-linking agent (A) by dissociating a protective group on the step sheet, and a fluororesin having a cross-linkable functional group The coating film obtained is dried at a temperature lower than the block dissociation temperature of the blocked isocyanate crosslinking agent. Step II: On the dried coating film obtained in Step I, the main film layer constituting resin is contained. Step III of coating the solution: The dried coating film of the fluororesin-containing liquid obtained in Step I, and the coating film of the main film layer-constituting resin-containing liquid obtained in Step II are used as the blocked isocyanate crosslinking agent. Step IV: Forming a substrate composed of a main film layer and a fluororesin layer by heating to a block dissociation temperature of 200 ° C. or less, directly on the main film layer side of the substrate obtained in Step III Via one or more layers, laminating a pressure-sensitive adhesive layer

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