JP2003327934A - Adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare an adhesive film having soil attachment resistance, closely adhering property of a printing ink and overlapped pasting property required as a polyolefinic adhesive film, and being treatable in a simple burning installation after use. <P>SOLUTION: This adhesive film obtained by laminating a coating layer consisting of a urethane-based resin (preferably an acrylic/urethane resin), a polyolefinic substrate layer and an adhesive layer in this order is provided by having ≥20% and <60% (preferably ≥30% and <40%) charged electricity- damping rate at 10 min after impressing an electric voltage. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative pressure-sensitive adhesive film suitably used as an outdoor or indoor advertising sticker, a display sticker, a decorative sticker, or the like. The pressure-sensitive adhesive film of the present invention includes a pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive film used for the above-mentioned applications is generally often referred to as a marking film. More specifically, the present invention is a so-called re-peelable type, which can be applied to an advertising signboard after printing or other decorations, and can be easily peeled off without sticking to an adherend after use. Is intended. [0003] A marking film is generally made of a soft vinyl chloride resin film as a base layer, and a pigment is kneaded into the base layer according to the application or purpose.
After printing and painting, apply an appropriate pressure-sensitive adhesive (pressure-sensitive adhesive) to one side of the base material layer according to the application and purpose, and form a pressure-sensitive adhesive layer. It is configured by laminating a release material layer such as release paper or a release film for the purpose of protecting the adhesive layer.In use, the release adhesive layer is peeled and the exposed adhesive layer is applied to a predetermined portion of the adherend. Used by pasting. Advertisement stickers used for signboards, advertising towers, shutters, show windows, etc .; outdoor use; decorative stripe stickers used for vehicles such as automobiles and motorcycles and ships such as motor boats; traffic signs , Road signs, display stickers used for information boards and the like. Among them, a re-peelable marking film, which is applied on a decorative signboard and peeled and discarded after being used for a short period of time, has attracted attention. [0005] Since the conventional removable marking film is made of a vinyl chloride resin film as a base material similarly to a normal outdoor or indoor marking film, hydrogen chloride gas and dioxin are generated when it is incinerated and discarded. For,
There is a problem that the treatment cannot be carried out with a simple incineration facility, and the durability of the simple incineration facility is reduced. Therefore, recently, there has been an increasing demand for a low environmental load type marking film that can be processed by a simple incineration facility. For example, JP-A-8-157780 proposes a marking film in which a polyolefin resin film is used as a base layer and an adhesive layer is laminated on the base layer. Further, it is described that since such a configuration enables incineration disposal, the recyclability is good. However, although the olefin resin film is used for the base material layer, the marking film described in the above-mentioned publication is particularly required for practical use of the re-peelable type marking film. The quality was not designed, and it could not be practically used as a PVC-free adhesive film. Heretofore, in order to improve the stain resistance of an olefin resin-based film, an antistatic agent has been added to the film, and the function has been exhibited by bleeding out the antistatic agent to the surface after film formation. By this measure, although the stain prevention effect is certainly exhibited, the printing ink adhesion and the lamination property (adhesive force on the back surface) required for the pressure-sensitive adhesive film product cannot be used for actual use. [0009] In other words, due to insufficient ink adhesion to the film surface after printing, ink peeling may occur due to slight physical stress, or a different color film may be used to enhance the appeal and decorativeness of the design. When they were laminated and bonded together, they were easily peeled off due to mischief and the like because the adhesiveness of the laminated film was low, and could not be used for actual use. These were mainly due to the antistatic agent that had been frozen out on the film surface. On the other hand, in order to solve these problems, there is a method in which a corona treatment is applied to an antistatic agent-containing film. Was not a practical solution. The inventors of the present invention have studied the above-mentioned problems of the marking film, and as a result, have found that a polyolefin resin is used as a film base, and an acrylic urethane-based resin is coated on one side of the base. Coating and laminating a pressure-sensitive adhesive layer on the opposite surface, and by applying a voltage to apply a specific range of the charge decay rate after 10 minutes, the stain resistance, printing ink adhesion, and lamination property are improved. The present invention was found to be significantly improved, and the present invention was completed. That is, the present invention provides a pressure-sensitive adhesive film having stain resistance, printing ink adhesion, and lamination property required as an olefin-based pressure-sensitive adhesive film, and which can be treated with a simple incineration facility after use. Aim. [0012] In order to achieve the above object, the present invention provides an adhesive film comprising a urethane-based resin coating layer, a polyolefin-based substrate layer and an adhesive layer laminated in this order. A pressure-sensitive adhesive film having a charge decay rate after 10 minutes of 20% or more and less than 60%.
Hereinafter, the present invention will be described in more detail. The polyolefin-based resin used in the polyolefin-based substrate layer of the removable pressure-sensitive adhesive film of the present invention refers to a polymer containing olefins, especially ethylene or / and propylene, as a main constituent unit, and is preferably used. One type of polyethylene or polypropylene or a mixture thereof is used. Among them, a polyolefin-based resin having high heat resistance is preferable, and a polypropylene-based resin is particularly preferable because a printing layer is required to be laminated. The thickness of the substrate layer is 50 to 3
The thickness is set to 00 μm, preferably 80 to 150 μm. The polyolefin-based substrate layer of the present invention also contains a lubricant, a nucleating agent, an antiblocking agent, an antioxidant, a light stabilizer, an ultraviolet absorber, an inorganic filler, an organic filler, and a flexibility-imparting elastomer. There is no problem at all. In the present invention, it is preferable to mix an organic pigment and an inorganic pigment in order to make the polyolefin-based substrate layer exhibit decorativeness. It is preferable that the pigments are mixed by using a masterbatch or the like, which is used as a general-purpose technique to enhance the dispersibility of the pigment in the resin. The polyolefin-based substrate layer in the present invention is obtained by blending the above-mentioned additives with a polyolefin-based resin.
A film can be formed by a T-die method, an inflation method, or the like as conventionally used. Further, the film may be formed by a calender molding machine. Further, there is no problem even if the base material layer has a multilayer structure of two or more layers. Since the formed substrate film generally has a low surface tension, it is desirable to improve the adhesion of the printing layer and the pressure-sensitive adhesive layer by surface modification by corona treatment. The coating layer is made of a urethane resin which has weather resistance and does not generate harmful gas even when burning waste, since the adhesive film of the present invention is often used outdoors. Specifically, a urethane-based coating layer made of a three-dimensionally crosslinked urethane-based resin such as a polyester urethane resin, a polyurethane resin, and an acrylic urethane resin is preferable, and an acrylic urethane resin is particularly preferably used. Examples of the urethane-based coating layer include polyester polyols, polyester urethane resins using acrylic polyols, acrylic urethane resins, polyether diols, polyester diols, and the like, in which the chain length is extended with diisocyanate, and triisocyanate. Examples include a polyurethane coat layer obtained by adding a functional isocyanate and three-dimensionally cross-linking to polymerize. A general-purpose antistatic agent may be appropriately added to the coating layer so as not to affect the adhesion of the printing ink described below. That is, since the antistatic agent bleeds out to the outermost surface and exhibits its effect by forming a thin film layer, there is also a problem that the printing ink laminated thereon is easily peeled off physically. The general-purpose antistatic agent referred to herein is an anionic type represented by an alkyl sulfonate, a cationic type represented by an alkyltrimethylammonium salt, an amphoteric active type represented by an alkyl betaine type, or a fatty acid alkylol. Any non-ionic type represented by an amide type may be used. They may be used alone or a plurality of them may be mixed at the same time. In the present invention, 10 minutes after applying a voltage to a pressure-sensitive adhesive film obtained by laminating a coat layer, which may contain an antistatic agent, and a pressure-sensitive adhesive layer to the olefin-based substrate film, Charge decay rate is 20% or more 6
It is less than 0%, preferably 30% or more and less than 40%.
Incidentally, the charge decay rate after 10 minutes when the voltage is applied is calculated from the remaining applied amount and the initial applied amount after 10 minutes, as described later in detail, when the output is stopped when the applied amount is saturated. Value. If it is less than 20%, the stain resistance is poor over time due to static electricity and the like. If it is more than 60%, the adhesion of the printing ink will be poor due to the antistatic agent bleeding to the surface. Sometimes problems easily occur. The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer of the present invention may be an acrylic resin-based or rubber-based pressure-sensitive adhesive. However, considering the outdoor use of the pressure-sensitive adhesive film, an acrylic-based pressure-sensitive adhesive is preferred. preferable. Usually, the (meth) acrylate monomer used as a main component of the acrylic pressure-sensitive adhesive layer is a (meth) acrylate ester of an alcohol having an alkyl group having 1 to 12 carbon atoms, preferably 4 to 4 carbon atoms. 1
(Meth) acrylic acid ester having an alkyl group of 2 is used. Specifically, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylate
Examples thereof include isooctyl acrylate, n-octyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate. These can be used alone or in combination. Due to the balance between tackiness and cohesiveness, etc., a homopolymer usually contains a (meth) acrylate having a glass transition temperature (Tg) of -50 ° C. or lower as a main component, and methyl (meth) acrylate and ethyl (meth) acrylate. (Meth) of lower alcohols such as
Acrylic esters can be used in combination. In addition, other than these vinyl monomers, a monomer copolymerizable therewith may be copolymerized. Examples of the monomer include a carboxyl group-containing monomer such as (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid, an anhydride thereof, and 2-hydroxyethyl (meth)
Acrylate, 4-hydroxybutyl acrylate,
There are hydroxyl-containing monomers such as polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, and caprolactone-modified (meth) acrylate. The pressure-sensitive adhesive may be a solvent-type acrylic pressure-sensitive adhesive polymerized in a solvent or an emulsion-type pressure-sensitive adhesive polymerized in water. Further, a block polymerization type pressure-sensitive adhesive obtained by irradiating a monomer mixture with ultraviolet light may be used. The thickness of the pressure-sensitive adhesive layer is preferably from 10 to 100 μm, and more preferably from 20 to 40 μm. The marking film is generally manufactured by applying a pressure-sensitive adhesive to a release paper material in advance by a quantitative coating method such as a reverse coating method, drying by heating, and then laminating the material on a base material. Further, the pressure-sensitive adhesive film of the present invention is provided as a product by laminating a release paper material on the pressure-sensitive adhesive layer. The release paper material is not particularly limited, and for example, a silicone-coated release paper can be used. EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. (Example 1) A polyolefin-based substrate was formed to a thickness of 80 µm by the T-die method with the composition shown in Table 1, and subjected to in-line corona treatment (42 dyne / cm 2).
Nippon Paint Co., Ltd. acrylic urethane resin paint “nax Superior” clear 100
10 parts by weight of isocyanate-based curing agent “HLS” manufactured by Nippon Polyurethane Co., Ltd.
Then, a pressure-sensitive adhesive layer and a release material layer were formed on the opposite surface of the coat layer to obtain a pressure-sensitive adhesive film. (Adhesive layer) An acrylic adhesive ("NM-1" manufactured by Sekisui Chemical Co., Ltd.) and an isocyanate-based curing agent ("Coronate 2094" manufactured by Nippon Polyurethane Co., Ltd.)
After mixing and stirring, dry thickness is 20 μm with a comma coater.
Was applied to a silicon-coated release paper to form a film, and this was laminated and laminated on the above-mentioned polyolefin substrate to form a pressure-sensitive adhesive layer to obtain a target marking film. (Examples 2 and 3) Adhesion was carried out in the same manner as in Example 1 except that a base material layer was prepared by blending the resins shown in Table 1 and a cationic antistatic agent "Electrostripper QN" was blended into the coat layer. A film was obtained. (Comparative Examples 1 and 2) A pressure-sensitive adhesive film was obtained in the same manner as in Example 1 except that a base material layer was prepared by compounding the resin shown in Table 1 and that an antistatic agent shown in Table 1 was added to the coat layer. Was. [Practical evaluation] Table 1 shows the results of evaluation of the charge decay rate, adhesion of printing ink, stain resistance, and incineration of the pressure-sensitive adhesive film obtained by the above-mentioned method. Each determination method is as follows. <Charge Decay Rate> An adhesive film for evaluation was attached to a static honest meter “Model: S-5109” manufactured by Shisido Electrostatic Co., Ltd., and a charging output of 7 kW was applied. When the applied amount was saturated, an output was added. Stopped, and the remaining applied amount after 10 minutes was measured. The charge decay rate was calculated by the following formula. (E ⁰ −E ′ / E ⁰ ) × 100 E ⁰ : Initial application amount E ′: Application amount after 10 minutes <Print ink adhesion> The surface of the adhesive film for evaluation was manufactured by Teikoku Ink Co., Ltd. Screen ink "PO
S "was applied with an ink on a 200 mesh screen and dried at 100 ° C. for 5 minutes. After that, JIS K
The ink adhesion was evaluated by a cross-cut evaluation method of 5400, and the results were expressed according to the following criteria.・ ・ ・: Number of peeling: 10 or less △: Number of peeling: 11 to 30 or less ×: Number of peeling: 31 or more <Stain resistance> A 30 cm square acrylic plate of an adhesive film for evaluation was used. The film was peeled off after being adhered and dust was flying every day. The film was placed in an outdoor simple tent warehouse at the Sekisui Chemical Co., Ltd., Amagasaki Plant, and the film surface contamination after 3 months was evaluated. ○ ・ ・ ・ No significant dirt is attached to the film surface,
No special cleaning is required. X: Significant dirt is adhered to the film surface, and there is a problem with decoration if cleaning is not performed. A 125 mm SUS plate was stuck neatly so as not to contain air bubbles, and the same adhesive film cut to a width of 25 mm was further pressed thereon with a 2 kg roller in accordance with JIS-Z-0237. After curing at 23 ° C. for 24 hours, the film was peeled off in the direction of 180 ° at a pulling speed of 300 mm / min, and the adhesive strength was measured.・ ・ ・: Adhesive force: 14.7 N / 25 mm or more △: Adhesive force: 4.9 or more, less than 14.7 N / 25 mm x: Adhesive force: less than 4.9 N / 25 mm > Each of the pressure-sensitive adhesive films prepared by the above method was sampled in a square of 5 cm, burned in a closed container, gas was collected in a syringe, and hydrogen gas and chlorine gas were qualitatively analyzed by gas chromatography.・ ・ ・: Hydrogen chloride and hydrogen gas were not detected. X: Hydrogen chloride and hydrogen gas were detected. The pressure-sensitive adhesive film of the present invention comprises a urethane-based resin coating layer, a polyolefin-based substrate layer and a pressure-sensitive adhesive layer laminated in this order, and is a polyolefin-based pressure-sensitive adhesive film. After that, unlike the conventional method, there is no need for landfill disposal, it can be incinerated in a simple incinerator, and is useful in this field as an environmentally friendly product. In addition, the charge decay after 10 minutes when a voltage is applied Since the ratio is 20% or more and less than 60%, the adhesive film has the stain resistance, printing ink adhesion, and lamination property required for an olefin-based adhesive film, and is extremely useful in this regard. is there. Of course, by selecting the material composition, it is possible to develop the same handling, peeling, and adhesive residue as the conventional vinyl chloride re-peelable pressure-sensitive adhesive film. It has various excellent effects such as stain resistance and printing ink adhesion.

Claims (1)

Claims 1. A pressure-sensitive adhesive film comprising a urethane-based resin coating layer, a polyolefin-based substrate layer, and a pressure-sensitive adhesive layer laminated in this order, and after 10 minutes when a voltage is applied. Wherein the charge decay rate is 20% or more and less than 60%.