KR20200059716A - Multi adhesive film and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a multi-layer adhesive film comprising an acrylic foam layer and an acrylic adhesive layer, and to a manufacturing method thereof. More specifically, the present invention relates to a multi-layer adhesive film having excellent interfacial bonding strength between the acrylic foam layer and the acrylic adhesive layer even without a barrier layer or a primer layer between the acrylic foam layer and the acrylic adhesive layer, and to a manufacturing method of the multi-layer adhesive film.

Description

Multilayer adhesive film and manufacturing method therefor {MULTI ADHESIVE FILM AND MANUFACTURING METHOD THEREOF}

The present invention relates to a multilayer adhesive film comprising an acrylic foam layer and an acrylic adhesive layer and a method for manufacturing the same, and to a multilayer adhesive film having an excellent interface bonding force between an acrylic foam layer and an acrylic adhesive layer and a method for manufacturing the same.

Multi-layer adhesive films including an acrylic foam layer are widely used for bonding between parts of electronic products and for bonding interior and exterior materials of automobiles. In general, a multilayer adhesive film including an acrylic foam layer is formed by laminating an acrylic foam layer and an acrylic adhesive layer, respectively.

On the other hand, when preparing the acrylic adhesive layer by thermally curing the composition for forming the adhesive layer during the production of the acrylic adhesive layer, when the acrylic foam layer and the acrylic adhesive layer are laminated, the residual solvent of the acrylic adhesive layer penetrates from the acrylic adhesive layer to the acrylic foam layer, and the acrylic There is a problem that the interface between the adhesive layer and the acrylic foam layer is separated. In the case of preparing the acrylic adhesive layer by photocuring the composition for forming the adhesive layer during the production of the acrylic adhesive layer, there is no problem that the residual solvent of the acrylic adhesive layer penetrates the acrylic foam layer when the acrylic foam layer and the acrylic adhesive layer are laminated. There is a problem that adhesion between the adhesive layer and the acrylic foam is difficult.

Therefore, in the case where the acrylic adhesive layer included in the multilayer adhesive film is manufactured by thermal curing or photocuring, a barrier layer or a primer layer is further required to prevent the interface separation between the acrylic foam layer and the acrylic adhesive layer. Therefore, there is a problem that the manufacturing process of the multilayer adhesive film is not only complicated, but also expensive.

Thus, in order to simplify the manufacturing process of the multilayer adhesive film and reduce the manufacturing cost, it is not only excellent in adhesion to the substrate, but also can prevent the interface separation between the acrylic foam layer and the acrylic adhesive layer without the barrier layer or primer layer. Multilayer adhesive films are required.

Korea Open Publication: KR 10-2012-0045347 A

Technical problem to be achieved by the present invention is to provide a multi-layer adhesive film having excellent interface bonding force between the acrylic foam layer and the acrylic adhesive layer.

In addition, the technical problem to be achieved by the present invention is to provide a simple method for producing a multi-layer adhesive film having excellent interface bonding force between the acrylic foam layer and the acrylic adhesive layer.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

An exemplary embodiment of the present invention is an acrylic foam layer; And an acrylic adhesive layer positioned on the acrylic foam layer, wherein the acrylic foam layer is a first acrylic system that is a partial polymerization of a first alkyl group-containing (meth) acrylate-based monomer and a first (meth) acrylic acid-based monomer. It is a cured product of the composition for forming a foam layer containing a prepolymer, and the acrylic adhesive layer contains a second alkyl group-containing (meth) acrylate-based monomer, a second (meth) acrylic acid-based monomer, and an N-alkyl group-substituted (meth) acrylamide-based monomer. It provides a multi-layered adhesive film, which is a partially polymerized product, and a cured product of a composition for forming an adhesive layer comprising a second acrylic prepolymer having a glass transition temperature of -30 ° C to 0 ° C.

Another embodiment of the present invention includes forming an acrylic foam layer; Forming an acrylic adhesive layer; And it provides a method for producing a multi-layer adhesive film according to an embodiment of the present invention comprising the step of thermal lamination to a temperature of 60 ℃ or more and 80 ℃ or less so that the acrylic adhesive layer is located on the acrylic foam layer.

The multilayer adhesive film according to an exemplary embodiment of the present invention has excellent interfacial bonding strength between the acrylic foam layer and the acrylic adhesive layer.

The multilayer adhesive film according to an exemplary embodiment of the present invention is excellent in durability at high temperatures.

The method of manufacturing a multi-layer adhesive film according to an exemplary embodiment of the present invention can realize a multi-layer adhesive film having excellent interfacial bonding strength between an acrylic foam layer and an acrylic adhesive layer and excellent durability at high temperatures.

1 is a view schematically showing an experiment for evaluating a holding force at a high temperature of the interface between the foam layer and the adhesive layer of the multilayer adhesive film according to an exemplary embodiment of the present invention.

In the present specification, when a part is to “include” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated.

Throughout this specification, when one member is positioned “on” another member, this includes not only the case where one member abuts another member, but also the case where another member exists between the two members.

In the present specification, the unit “parts by weight” may mean a ratio of weights between components.

In the present specification, the term "alkyl group" may mean to include a carbon chain structure in which an unsaturated bond is not present in the functional group, and means to include a straight chain or branched carbon chain structure having 1 to 20 carbon atoms. Can be.

In the present specification, the term "(meth) acrylate" may mean acrylate or methacrylate.

In the present specification, the term "monomer" may mean a unit for forming a polymer.

In this specification, the term "prepolymer" means a partially polymerized product.

In this specification, the term "glass transition temperature (Glass Transition Temperature, Tg)" using the DSC (Differential Scanning Calorimeter, Q-1000, TA Instrument Co., Ltd.) heating in a temperature range of -70 ℃ to 150 ℃ It was measured by heating at a rate of 10 ° C./min and determined as the midpoint of the DSC curve.

In the present specification, the term "weight average molecular weight" is measured as a conversion value for polystyrene measured by GPC (Gel Permeation Chromatography).

Hereinafter, the present invention will be described in more detail.

An exemplary embodiment of the present invention is an acrylic foam layer; And an acrylic adhesive layer located on the acrylic foam layer, wherein the acrylic foam layer is a first acrylic system that is a partial polymerization of a first alkyl group-containing (meth) acrylate-based monomer and a first (meth) acrylic acid-based monomer. It is a cured product of the composition for forming a foam layer containing a prepolymer, and the acrylic adhesive layer contains a second alkyl group-containing (meth) acrylate-based monomer, a second (meth) acrylic acid-based monomer, and an N-alkyl group-substituted (meth) acrylamide-based monomer. It provides a multi-layered adhesive film, which is a partially polymerized product, and is a cured product of a composition for forming an adhesive layer comprising a second acrylic prepolymer having a glass transition temperature of -30 ° C to 0 ° C.

According to an exemplary embodiment of the present invention, the first acrylic prepolymer included in the foam layer forming composition is a partially polymerized product obtained by mixing a first alkyl group-containing (meth) acrylate-based monomer and a first (meth) acrylic acid-based monomer, and photopolymerizing Can be

According to an exemplary embodiment of the present invention, the first alkyl group-containing (meth) acrylate-based monomer may be included in an amount of 80 parts by weight or more and 95 parts by weight or less based on 100 parts by weight of the first acrylic prepolymer. Specifically, the content of the first alkyl group-containing (meth) acrylate-based monomer is 80 parts by weight or more and 90 parts by weight or less, 85 parts by weight or more, 95 parts by weight or less, 90 parts by weight or more with respect to 100 parts by weight of the first acrylic prepolymer It may be 95 parts by weight or less or 85 parts by weight or more and 90 parts by weight or less. When the content of the first alkyl group-containing (meth) acrylate-based monomer is within the above range, adhesion performance of an acrylic foam layer that is a cured product of the composition for forming the foam layer may be improved. That is, adhesion to the member to be adhered can be improved.

According to an exemplary embodiment of the present invention, the first alkyl group-containing (meth) acrylate-based monomer is methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) Acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethyl It may be one or more selected from butyl (meth) acrylate, n-octyl (meth) acrylate, and isooctyl (meth) acrylate.

According to one embodiment of the present invention, the first (meth) acrylic acid-based monomer may be included in an amount of 5 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the first acrylic prepolymer. Specifically, the content of the first (meth) acrylic acid-based monomer is 5 parts by weight or more and 15 parts by weight or less, 10 parts by weight or more, 15 parts by weight or less, or 5 parts by weight or more and 10 parts by weight with respect to 100 parts by weight of the first acrylic prepolymer It may be: When the content of the first (meth) acrylic acid-based monomer is within the above range, adhesion performance of an acrylic foam layer that is a cured product of the composition for forming the foam layer may be improved. In addition, when laminating the acrylic foam layer and the adhesive layer, interfacial adhesion due to interaction between the first (meth) acrylic acid-based monomer component of the acrylic foam layer and the N-alkyl group-substituted (meth) acrylamide-based monomer component of the acrylic adhesive layer This can be improved.

According to an exemplary embodiment of the present invention, the first (meth) acrylic acid-based monomer is acrylic acid, methacrylic acid, 2-carboxyethyl acrylic acid, 3-carboxypropyl acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- It may be one or more selected from (meth) acryloyloxypropyl acid and 4- (meth) acryloyloxybutyl acid. The first (meth) acrylic acid-based monomer may improve cohesion and improve adhesion performance of the acrylic foam layer, which is a cured product of the foam layer forming composition.

According to an exemplary embodiment of the present invention, the glass transition temperature of the first acrylic prepolymer may be -50 ° C or higher-40 ° C or lower. When the glass transition temperature of the first acrylic prepolymer is within the above range, the acrylic foam layer prepared using the composition for forming the foam layer may secure flexible properties. In addition, since chemical bonding between the acrylic foam layer and the acrylic adhesive layer can be promoted, peeling of the acrylic foam layer and the acrylic adhesive layer can be effectively prevented.

According to an exemplary embodiment of the present invention, the weight average molecular weight of the first acrylic prepolymer included in the composition for forming the acrylic foam layer may be 5 million g / mol or more and 7 million g / mol or less. Specifically, the weight average molecular weight of the first acrylic prepolymer is 5 million g / mol or more and 6 million g / mol or less, 5.5 million g / mol or more and 6.5 million g / mol or less, or 6 million g / mol or more and 7 million g / mol It may be: When the weight average molecular weight of the first acrylic prepolymer is within the above range, the acrylic foam layer prepared using the composition for forming the foam layer may have excellent interfacial adhesion with the acrylic adhesive layer.

According to an exemplary embodiment of the present invention, the viscosity of the first acrylic prepolymer may be 5,000 cP or more and 7,000 cP or less. Specifically, it may be 5,000 cP or more and 6,000 cP or less, 5,500 cP or more, 6,500 cP or less, or 6,000 cP or more and 7,000 cP or less. When the viscosity of the first acrylic prepolymer is within the above range, the acrylic foam layer prepared using the composition for forming the foam layer may have excellent interfacial adhesion with the acrylic adhesive layer. In addition, the multi-layer adhesive film including the acrylic foam layer can be attached to the member to be adhered with excellent adhesion.

According to an exemplary embodiment of the present invention, the composition for forming the foam layer may further include a diluting monomer for adjusting the viscosity of the composition in addition to the first acrylic prepolymer. The diluting monomer may include, for example, monomers used when forming the first acrylic prepolymer. That is, the composition for forming the foam layer may further include at least one selected from the first alkyl group-containing (meth) acrylate-based monomer and the first (meth) acrylic acid-based monomer. In addition, the composition for forming the foam layer may further include a photoinitiator, a multifunctional crosslinking agent, an inorganic filler, a hollow filler, a surfactant, an organic / inorganic pigment, an antioxidant, and the like. However, it is not limited thereto.

The photoinitiator is not particularly limited as long as it is an initiator that generates radicals by light to trigger crosslinking, but is, for example, at least one selected from acetophenone-based compounds, biimidazole-based compounds, triazine-based compounds, and oxime-based compounds. Can be. The photoinitiator may be included in an amount of 0.1 part by weight or more and 1 part by weight or less based on 100 parts by weight of the first acrylic prepolymer.

The polyfunctional cross-linking agent is not particularly limited, for example, hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate Diacrylate-based crosslinking agents such as acrylate and tripropylene diacrylate; Triacrylate-based crosslinking agents; Aziridine-based crosslinking agent; Epoxy crosslinking agents; And urethane-based crosslinking agents. The multifunctional crosslinking agent may be included in an amount of 0.05 parts by weight or more and 0.5 parts by weight or less based on 100 parts by weight of the first acrylic prepolymer.

The inorganic filler can be used without limitation those used in the production of the foam layer in the art. For example, the inorganic filler may include silica, but is not limited thereto.

The hollow filler is intended to lower the density of the foam layer, and may include, for example, one or more of product name Xpancel (polymeric sphere expancel 551DU), product name glass macroballoon, and glass bubble, but is not limited thereto. It is not.

The surfactant is not particularly limited as long as it can improve the stability of bubbles formed in the composition for forming the foam layer and in the acrylic foam layer, and prevent the adhesion of the acrylic foam layer from being lowered, but is not particularly limited. Surfactants and / or silicone surfactants.

According to an exemplary embodiment of the present invention, the composition for forming the foam layer may be a solvent-free type. That is, the composition for forming the foam layer may not include a separate solvent. Therefore, it is possible to minimize the risk to the volatile solvent.

The acrylic foam layer may be a foam layer prepared by photocuring the composition for forming the foam layer. The acrylic foam layer according to an exemplary embodiment of the present invention may have excellent adhesiveness and excellent bubble stability.

According to an exemplary embodiment of the present invention, the second acrylic prepolymer included in the composition for forming an adhesive layer includes a second alkyl group-containing (meth) acrylate-based monomer, a second (meth) acrylic acid-based monomer, and N-alkyl group substitution (meth ) It may be a partially polymerized mixture of acrylamide-based monomers and photopolymerized.

According to an exemplary embodiment of the present invention, the glass transition temperature of the second acrylic prepolymer is -30 ° C or higher and 0 ° C or lower. Specifically, the glass transition temperature of the second acrylic prepolymer may be -30 ° C or higher-15 ° C or lower or-27 ° C or higher-17 ° C or lower. When the glass transition temperature of the second acrylic prepolymer is within the above range, the acrylic adhesive layer prepared using the composition for forming the adhesive layer can secure flexible properties.

According to one embodiment of the present invention, the second alkyl group-containing (meth) acrylate-based monomer may be included in an amount of 60 parts by weight or more and 80 parts by weight or less based on 100 parts by weight of the second acrylic prepolymer. Specifically, the content of the second alkyl group-containing (meth) acrylate-based monomer may be 60 parts by weight or more and 70 parts by weight or less or 65 parts by weight or more and 75 parts by weight or less based on 100 parts by weight of the second acrylic prepolymer. When the content of the second alkyl group-containing (meth) acrylate-based monomer is within the above range, adhesion performance of the acrylic adhesive layer, which is a cured product of the composition for forming the adhesive layer, may be improved. That is, it is possible to improve the adhesion to the member to be adhered.

According to an exemplary embodiment of the present invention, the second alkyl group-containing (meth) acrylate-based monomer is methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) Acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethyl It may be one or more selected from butyl (meth) acrylate, n-octyl (meth) acrylate, and isooctyl (meth) acrylate.

According to an exemplary embodiment of the present invention, the second (meth) acrylic acid-based monomer may be included in an amount of 1 part by weight or more and 5 parts by weight or less with respect to 100 parts by weight of the second acrylic prepolymer. Specifically, the content of the second (meth) acrylic acid-based monomer may be 1 part by weight or more and 3 parts by weight or less or 2 parts by weight or more and 5 parts by weight or less with respect to 100 parts by weight of the second acrylic prepolymer. When the content of the second (meth) acrylic acid-based monomer is within the above range, adhesion performance of the acrylic adhesive layer, which is a cured product of the composition for forming the adhesive layer, may be improved.

According to an exemplary embodiment of the present invention, the second (meth) acrylic acid-based monomer is acrylic acid, methacrylic acid, 2-carboxyethylacrylic acid, 3-carboxypropylacrylic acid, 2- (meth) acryloyloxyacetic acid, 3- It may be one or more selected from (meth) acryloyloxypropyl acid and 4- (meth) acryloyloxybutyl acid. The second (meth) acrylic acid-based monomer may improve the adhesion performance of the acrylic adhesive layer which is a cured product of the composition for forming the adhesive layer.

According to an exemplary embodiment of the present invention, the N-alkyl group-substituted (meth) acrylamide-based monomer may be included in an amount of 20 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the second acrylic prepolymer. Specifically, the content of the N-alkyl group substituted (meth) acrylamide monomer is 20 parts by weight or more and 40 parts by weight or less, 25 parts by weight or more, 40 parts by weight or less, or 25 parts by weight or more and 35 parts by weight or more based on 100 parts by weight of the second acrylic prepolymer. It may be less than parts by weight. When the content of the N-alkyl group-substituted (meth) acrylamide-based monomer is within the above range, chemical bonding between the acrylic foam layer and the acrylic adhesive layer may be promoted when laminating the acrylic foam layer and the adhesive layer. In addition, the adhesive performance of the acrylic adhesive layer, which is a cured product of the composition for forming the adhesive layer, may be improved.

According to an exemplary embodiment of the present invention, the N-alkyl group-substituted (meth) acrylamide-based monomer is N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-ethylmethylacrylamide, N, N-ethylpropylacrylamide, N, N-dipropylacrylamide, N, N-butylpropylacrylamide, N, N-dibutylacrylamide, N, N-methylpropylacrylamide, N, N-butylmethylacryl Amide, N, N-butylethylacrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide and N-hydroxyethyl (meth ) It may be one or more selected from acrylamide. The N-alkyl group-substituted (meth) acrylamide-based monomer can improve the adhesion performance of the acrylic adhesive layer, which is a cured product of the composition for forming the adhesive layer. In addition, when laminating the acrylic foam layer and the adhesive layer, the interface is caused by interaction between the first (meth) acrylic acid-based monomer component of the acrylic foam layer and the N-alkyl group-substituted (meth) acrylamide-based monomer component of the acrylic adhesive layer. Adhesion can be improved.

According to an exemplary embodiment of the present invention, the weight average molecular weight of the second acrylic prepolymer included in the composition for forming the acrylic adhesive layer may be 700,000 g / mol or more and 900,000 g / mol or less. Specifically, the weight average molecular weight of the second acrylic prepolymer included in the composition for forming the acrylic adhesive layer may be 700,000 g / mol or more and 800,000 g / mol or less, or 800,000 g / mol or more and 900,000 g / mol or less. . When the weight average molecular weight of the second acrylic prepolymer is within the above range, the acrylic adhesive layer prepared using the composition for forming the adhesive layer may have excellent interfacial adhesion with the acrylic foam layer.

According to an exemplary embodiment of the present invention, the viscosity of the second acrylic prepolymer may be 650 cP or more and 2,000 cP or less. Specifically, the viscosity of the second acrylic prepolymer may be 690 cP or more, 1,700 cP or less, 650 cP or more, 1,700 cP or less, or 690 cP or more and 2,000 cP or less. When the viscosity of the second acrylic prepolymer is within the above range, the acrylic adhesive layer prepared using the composition for forming the adhesive layer may have excellent interfacial adhesion with the acrylic foam layer.

According to an exemplary embodiment of the present invention, the composition for forming an adhesive layer may further include a diluent monomer in addition to the second acrylic prepolymer. The diluting monomer may further include, for example, at least one selected from the second alkyl group-containing (meth) acrylate-based monomer and the second (meth) acrylic acid-based monomer. On the other hand, it is preferable not to include the said N-alkyl group substituted (meth) acrylamide type monomer as a diluting monomer. In addition, the composition for forming an adhesive layer may further include a photoinitiator, a multifunctional crosslinking agent, an antioxidant, and a surfactant. However, it is not limited thereto.

The photoinitiator, the multifunctional crosslinking agent, the antioxidant and the surfactant that may be included in the composition for forming the adhesive layer may be the same as those included in the composition for forming the foam layer, but are not limited thereto.

The photoinitiator that may be included in the composition for forming the adhesive layer may be included in an amount of 0.1 parts by weight or more and 0.3 parts by weight or less based on 100 parts by weight of the second acrylic prepolymer, and the multifunctional crosslinking agent is 100 parts by weight of the second acrylic prepolymer. It can be included in an amount of 0.05 parts by weight or more and 0.15 parts by weight or less based on parts.

According to an exemplary embodiment of the present invention, the composition for forming an adhesive layer may be a solvent-free type. That is, the composition for forming the adhesive layer may not include a separate solvent. Therefore, it is possible to minimize the risk to the volatile solvent.

The acrylic adhesive layer may be an adhesive layer prepared by photocuring the composition for forming the adhesive layer.

According to an exemplary embodiment of the present invention, the thickness ratio of the acrylic foam layer and the acrylic adhesive layer may be 5: 1 to 15: 1. When the thickness ratio of the acrylic foam layer and the acrylic adhesive layer is within the above range, each of the acrylic foam layer and the acrylic adhesive layer may have excellent adhesion to a member to be adhered.

According to an exemplary embodiment of the present invention, the thickness of the acrylic foam layer may be 100 μm or more and 1100 μm or less. However, it is not limited thereto. When the thickness of the acrylic foam layer is within the above range, the acrylic foam layer may have excellent physical properties and excellent adhesion to a member to be adhered.

According to an exemplary embodiment of the present invention, the thickness of the acrylic adhesive layer may be 30 μm or more and 100 μm or less. However, the present invention is not limited thereto. When the thickness of the acrylic adhesive layer is within the above range, the acrylic adhesive layer may have excellent physical properties and excellent adhesion to the target member.

Another embodiment of the present invention includes forming an acrylic foam layer; Forming an acrylic adhesive layer; And it provides a method for producing a multi-layer adhesive film according to an embodiment of the present invention comprising the step of thermal lamination to a temperature of 60 ℃ or more and 80 ℃ or less so that the acrylic adhesive layer is located on the acrylic foam layer. In the manufacturing method according to an exemplary embodiment of the present invention, the acrylic foam layer, the acrylic adhesive layer, and the multilayer adhesive film are as described above.

According to an exemplary embodiment of the present invention, the step of forming the acrylic foam layer may be to apply the composition for forming the acrylic foam layer on a release film and cure.

According to an exemplary embodiment of the present invention, the step of forming the acrylic adhesive layer may be to apply the composition for forming the acrylic adhesive layer on a release film and cure.

According to an exemplary embodiment of the present invention, the method of applying the composition for forming the acrylic foam layer and the composition for forming the acrylic adhesive layer is not particularly limited, for example, spray coating, gravure coating, microgravure coating, roll coating, fla Any one of flexo coating, screen coating, spin coating, flow coating, knife coating, nozzle coating, rotary screen coating, reverse loss coating, comma coating, lip coating and slot die coating can be used.

According to an exemplary embodiment of the present invention, the method for curing the composition for forming the acrylic foam layer and the composition for forming the acrylic adhesive layer is not particularly limited, and may be cured by a method of thermal curing or photocuring. The photocuring may be, for example, curing by irradiating ultraviolet (UV) light for 3 minutes or more and 7 minutes or less using a black light or a metal halide lamp.

According to the exemplary embodiment of the present invention, the acrylic foam layer and the acrylic adhesive layer may be heat-bonded at a temperature of 60 ° C or higher and 80 ° C or lower. In this case, peeling off the acrylic foam layer and the acrylic adhesive layer due to the interaction of the first (meth) acrylic acid-based monomer component of the acrylic foam layer with the N-alkyl group-substituted (meth) acrylamide-based monomer component of the acrylic adhesive layer. It may not be easy. That is, the interface bonding force between the acrylic foam layer and the acrylic adhesive layer can be effectively improved. Therefore, the method of manufacturing a multilayer adhesive film according to an exemplary embodiment of the present invention can produce a multilayer adhesive film having excellent interfacial bonding strength by laminating two layers without using a primer layer or a barrier layer.

According to an exemplary embodiment of the present invention, the thermal paper may be positioned such that the acrylic foam layer and the acrylic adhesive layer face each other, and may be thermally bonded at a temperature of 60 ° C. or more and 80 ° C. or less. For example, it may be laminated by passing an acrylic foam layer and an acrylic adhesive layer positioned to face each other between roll to roll equipment.

Hereinafter, examples will be described in detail to specifically describe the present invention. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present invention to those skilled in the art.

Manufacturing example  1-acrylic Foamy  Produce

90 parts by weight of 2-ethylhexyl acrylate (2-EHA), 10 parts by weight of 10 parts by weight of acetic acid (AA) 100 parts by weight of the first acrylic prepolymer, 50 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of acetic acid, as a photoinitiator Irgacure 651 1 part by weight, 0.5 part by weight of 1,6-hexanediol diacrylate (HDDA) as a crosslinking agent, 10 parts by weight of glass bubble (3M company) as a hollow filler and 2 parts by weight of silica (Evonik) as an inorganic filler A composition for forming an acrylic foam layer was prepared.

The molecular weight of the first acrylic prepolymer was 6 million g / mol, and the viscosity was 7,000 cP at 25 ° C.

The composition for forming the acrylic foam layer was purged with nitrogen gas to form pores.

The composition for forming the acrylic foam layer in which the pores were formed was applied on a polyethylene terephthalate (PET) film as a release film. Thereafter, the composition for forming the acrylic foam layer was irradiated with UV with a UV lamp for 5 minutes to prepare an acrylic foam layer having a thickness of 100 μm.

Manufacturing example  2-acrylic Of the adhesive layer (A)  Produce

68 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of N, N-dimethylacrylamide (DMAA) and 2 parts by weight of acetic acid, 100 parts by weight of the second acrylic prepolymer which is a partially polymerized product, 0.2 parts by weight of Irgacure 651 as a photoinitiator and crosslinking agent A composition for forming an acrylic adhesive layer containing 0.1 parts by weight of 1,6-hexanediol diacrylate (HDDA) was prepared.

The second acrylic prepolymer had a glass transition temperature of -17 ° C, a molecular weight of 700,000 g / mol, and a viscosity of 690 cP at 25 ° C.

The composition for forming the acrylic adhesive layer was applied on a polyethylene terephthalate (PET) film as a release film. Thereafter, the composition for forming the acrylic adhesive layer was irradiated with UV for 5 minutes to prepare an acrylic adhesive layer having a thickness of 100 μm.

Manufacturing example  3-acrylic Of the adhesive layer (B)  Produce

When preparing the second acrylic prepolymer, an acrylic adhesive layer was prepared in the same manner as in Production Example 2, except that 30 parts by weight of N, N-diethylacrylamide (DEAA) was used instead of 30 parts by weight of N, N-dimethylacrylamide. .

The glass transition temperature of the second acrylic prepolymer was -27 ° C, the molecular weight was 900,000 g / mol, and the viscosity was 1,700 cP at 25 ° C.

Manufacturing example  4-acrylic Of adhesive layer (C)  Produce

90 parts by weight of 2-ethylhexyl acrylate (2-EHA), 10 parts by weight of acetic acid (AA), 100 parts by weight of the first acrylic prepolymer, 40 parts by weight of 2-ethylhexyl acrylate, 4 parts by weight of acetic acid, as a photoinitiator Irgacure 651 acrylic adhesive layer in the same manner as in Preparation Example 2, except that a composition for forming an acrylic adhesive layer comprising 0.35 parts by weight of 1,6-hexanediol diacrylate (HDDA) as 0.3 parts by weight and a crosslinking agent was prepared. Was prepared.

The second acrylic prepolymer had a glass transition temperature of -49 ° C, a molecular weight of 6 million g / mol, and a viscosity of 7,000 cP at 25 ° C.

Example  One

Multi-layer adhesive film by thermally laminating the acrylic foam layer according to Preparation Example 1 and the acrylic adhesive layer (A) according to Preparation Example 2 with roll to roll equipment (EXCELAM II-655Q, GMP) Was prepared.

Example  2

A multilayer adhesive film was prepared in the same manner as in Example 1, except that the acrylic adhesive layer (B) according to Preparation Example 3 was used as the acrylic adhesive layer.

Comparative example  One

A multilayer adhesive film was prepared in the same manner as in Example 1, except that the acrylic adhesive layer (C) according to Preparation Example 4 was used as the acrylic adhesive layer.

Of multilayer adhesive film Foam layer Adhesive layer  At high temperatures in the liver interface retention  evaluation

1 is a view schematically showing an experiment for evaluating a holding force at a high temperature of an interface between a foam layer and an adhesive layer of a multilayer adhesive film according to an exemplary embodiment of the present invention, using a SUS substrate and / or an automotive coating substrate as a substrate.

As description SUS  When only mention is used

The multilayer adhesive films according to Examples 1 and 2 and Comparative Example 1 were cut to 1 inch × 1 inch. The multilayer adhesive film was placed between two SUS substrates, pressed and pressed for 1 minute under a load of 6 kg, and then allowed to stand at room temperature for 24 hours. And, it was evaluated whether the interface between the acrylic foam layer and the acrylic adhesive layer of the multilayer adhesive film was separated by attaching a 2 kg weight in an 80 ° C. chamber for 10,000 minutes.

Table 1 below shows the case where the interface between the acrylic foam layer and the acrylic adhesive layer is not separated, and ○ when separated. In addition, when the interface is separated, the separated time is also shown.

As a base material, the car painting base material and SUS  When using equipment

Automobile coating materials and SUS materials using urethane-based or melamine-based paints were prepared. The multilayer adhesive films according to Examples and Comparative Examples were cut to 1 inch × 1 inch. The multilayer film was placed on the SUS substrate so that the acrylic foam layer was in contact, and the coated substrate was placed on the multilayer film, then pressed and pressed for 1 minute under a load of 6 kg, and allowed to stand at room temperature for 24 hours. And, it was evaluated whether the interface between the acrylic foam layer and the acrylic adhesive layer was separated by putting a 2 kg weight in an 80 ° C. chamber for 10,000 minutes.

Table 1 below shows the case where the interface between the acrylic foam layer and the acrylic adhesive layer is not separated, and ○ when separated.

SUS  Of the multi-layer adhesive film to the substrate Peeling force  Measure

Untreated PET and SUS substrates having a thickness of 50 μm were prepared. The multilayer adhesive films according to Examples 1 and 2 and Comparative Example 1 were cut to 1 inch (width) x 20 cm (length). The multilayer adhesive film was placed on the untreated PET having a thickness of 50 μm so that the acrylic foam layer was in contact, and after placing the SUS substrate on the multilayer adhesive film, it was attached to prevent bubbles from reciprocating 5 times with a 2 kg roller. . Subsequently, after standing for 30 minutes, a 180 ° peel force was measured using a physical property analyzer (TA.XT plus, stable micro systems company) at a measurement speed of 300 mm / min. Table 1 below shows the peel strength of the multilayer adhesive film to the SUS substrate.

Of multi-layer adhesive film to painted substrate Peeling force  Measure

An automotive coating substrate using 50-µm-thick untreated PET and urethane-based or melamine-based paints was prepared. The multilayer adhesive films according to Examples 1 and 2 and Comparative Example 1 were cut to 1 inch (width) x 20 cm (length). The multilayer adhesive film was placed on the untreated PET having a thickness of 50 µm so that the acrylic foam layer was in contact, and after placing the automotive coating substrate on the multilayer film, it was attached to prevent bubbles from reciprocating 5 times with a 2 kg roller. . Thereafter, after leaving for 30 minutes, a 180 ° peel force was measured while using a physical property analyzer (TA.XT plus, stable micro systems, Inc.) at a measurement speed of 300 mm / min. Table 1 below shows the peel strength of the multi-layer adhesive film to the coating substrate.

Evaluation of holding power at high temperature at the interface between the foam layer and the adhesive layer Peeling power to SUS substrate
(Unit: kgf / inch) Peeling power against painted substrate
(Unit: kgf / inch) SUS only
(Interface separation time) Use of automotive paint and SUS materials Example 1 ○
(More than 10,000 minutes) ○ 2.0 2.4 Example 2 ○
(More than 10,000 minutes) ○ 1.7 1.9 Comparative Example 1 Ⅹ
(317 minutes) Ⅹ 2.0 1.7

As shown in Table 1, the multi-layered adhesive films of Examples 1 and 2 do not fall off the interface between the foam layer and the adhesive layer at high temperature, and the time for maintaining the non-falling state is at least 10,000 minutes, and the adhesive layer and the foam layer at high temperature. It was found that the interfacial adhesion between the layers was excellent. In addition, it was found that the multilayer adhesive films of Examples 1 and 2 had a greater peeling force to the coating substrate than the peeling force to the SUS substrate, and thus the adhesion to the coating substrate was remarkably excellent.

On the other hand, when preparing the second acrylic prepolymer included in the acrylic adhesive layer, the multi-layer of Comparative Example 1 using a second acrylic prepolymer having a glass transition temperature of -49 ° C without containing an N-alkyl group-substituted (meth) acrylamide-based monomer Since the adhesive film has a remarkably short time for separating the interface at a high temperature, it was found that the interfacial adhesive strength between the foam layer and the adhesive layer at high temperature is weak, and thus the durability is not excellent. In addition, the multi-layered adhesive film of Comparative Example 1 was found to have less peel strength to the coated substrate than the peel strength to the SUS substrate, and thus the peel strength to the coated substrate was not excellent.

Therefore, it can be seen that the multi-layer adhesive film having excellent interfacial bonding strength according to an embodiment of the present invention has excellent durability at high temperature and excellent adhesion to a member to be adhered. In particular, it can be seen that the adhesion to the coating substrate is excellent.

Claims (13)

Acrylic foam layer; And
A multi-layer adhesive film comprising an acrylic adhesive layer located on the acrylic foam layer,
The acrylic foam layer is a cured product of a composition for forming a foam layer comprising a first acrylic prepolymer that is a partial polymer of a first alkyl group-containing (meth) acrylate-based monomer and a first (meth) acrylic acid-based monomer,
The acrylic adhesive layer is a partially polymerized product of a second alkyl group-containing (meth) acrylate-based monomer, a second (meth) acrylic acid-based monomer, and an N-alkyl group-substituted (meth) acrylamide-based monomer, having a glass transition temperature of -30 ° C or higher A multilayer adhesive film that is a cured product of a composition for forming an adhesive layer comprising a second acrylic prepolymer at 0 ° C or less. According to claim 1,
The first alkyl group-containing (meth) acrylate-based monomer is a multi-layer adhesive film contained in an amount of 80 parts by weight or more and 95 parts by weight or less based on 100 parts by weight of the first acrylic prepolymer. According to claim 1,
The first alkyl group-containing (meth) acrylate-based monomer and the second alkyl group-containing (meth) acrylate-based monomer are each independently methyl (meth) acrylate, ethyl (meth) acrylate, and n-propyl (meth) acrylate , Isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) Multilayer adhesive film which is at least one selected from acrylate, 2-ethylbutyl (meth) acrylate, n-octyl (meth) acrylate and isooctyl (meth) acrylate. According to claim 1,
The first (meth) acrylic acid-based monomer is a multi-layer adhesive film contained in an amount of 5 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the first acrylic prepolymer. According to claim 1,
The first (meth) acrylic acid-based monomer and the second (meth) acrylic acid-based monomer are each independently acrylic acid, methacrylic acid, 2-carboxyethylacrylic acid, 3-carboxypropylacrylic acid, 2- (meth) acryloyloxyacetic acid , 3- (meth) acryloyloxypropyl acid and 4- (meth) acryloyloxybutyl acid. According to claim 1,
The second alkyl group-containing (meth) acrylate-based monomer is a multi-layer adhesive film contained in an amount of 60 parts by weight or more and 80 parts by weight or less based on 100 parts by weight of the second acrylic prepolymer. According to claim 1,
The second (meth) acrylic acid-based monomer is a multi-layer adhesive film contained in an amount of 1 part by weight or more and 5 parts by weight or less based on 100 parts by weight of the second acrylic prepolymer. According to claim 1,
The N-alkyl group-substituted (meth) acrylamide-based monomer is a multi-layer adhesive film contained in an amount of 20 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the second acrylic prepolymer. According to claim 1,
The N-alkyl group-substituted (meth) acrylamide-based monomers are N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-ethylmethylacrylamide, N, N-ethylpropylacrylamide, N, N-dipropylacrylamide, N, N-butylpropylacrylamide, N, N-dibutylacrylamide, N, N-methylpropylacrylamide, N, N-butylmethylacrylamide and N, N-butylethylacryl A multilayer adhesive film having one or more selected from amides. According to claim 1,
The multi-layer adhesive film having a thickness ratio of the acrylic foam layer and the acrylic adhesive layer is 5: 1 to 15: 1. According to claim 1,
The thickness of the acrylic foam layer is a multi-layer adhesive film having a thickness of 100 μm or more and 1100 μm or less. According to claim 1,
The acrylic adhesive layer has a thickness of 30 μm or more and 100 μm or less. Forming an acrylic foam layer;
Forming an acrylic adhesive layer; And
A method for manufacturing a multi-layer adhesive film according to any one of claims 1 to 12, comprising the step of thermal laminating at a temperature of 60 ° C. or more and 80 ° C. or less so that the acrylic adhesive layer is located on the acrylic foam layer.

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