JP7720883B2 - Peelable adhesive layer and laminate - Google Patents

Description

The present invention relates to a peelable adhesive layer and a laminate.

Removable coatings are sometimes applied to the exterior of automobiles (e.g., clear coats on the exterior of automobiles) for the purpose of changing the color or protecting the exterior. Such coatings are used for a certain period of time and then peeled off. High coating performance is required for the exterior of automobiles during this period of use. Paints for removable coatings are widely available, for example, those made by dissolving synthetic rubbers such as styrene-butadiene copolymers in organic solvents such as xylene, ethylbenzene, acetone, and methyl ethyl ketone. These paints release volatile organic compounds into the air during the drying process, raising health and environmental concerns. Given this background, there has been a demand in recent years for water-based paints for removable coatings (see, for example, Patent Document 1).

US Patent Application Publication No. 2020/0216682

Such coatings must maintain adequate adhesion from the time they are applied until they are finally removed, so that they do not peel off accidentally and can be removed when desired.

When the present inventors attempted to apply a conventional water-based one-component paint to the exterior of an automobile, the following problems arose.
1. Adhesion that will not come off during normal use. 2. Peelability that allows you to peel it off whenever you want.

While the adhesiveness or peelability of the coating film was adequate at the beginning of its creation, heat (e.g., summer temperatures) gradually increased adhesion, and the peelability did not last.

The present invention therefore aims to provide a peelable adhesive layer that has sufficient adhesion to prevent peeling during normal use and excellent releasability that allows peeling whenever desired. The present invention also aims to provide a laminate that includes such a peelable adhesive layer.

The peelable adhesive layer according to the present invention comprises:
It is a coating film of paint for adhesive layer,
the adhesive layer coating material is a two-component type consisting of a first agent containing a water-dispersible acrylic resin and a water-dispersible urethane resin, and a second agent containing an isocyanate;
The water-dispersible urethane resin has a glass transition temperature (Tg) of −80 to 0° C.,
the hydroxyl value of the water-dispersible acrylic resin is 40 to 165 mg KOH/g;
The ratio (NCO/OH) of the number of moles of isocyanate groups in the isocyanate to the number of moles of hydroxyl groups in the first agent is 0.5 to 2.0, which provides a peelable adhesive layer with sufficient adhesion to prevent peeling during normal use and excellent releasability to allow peeling at a desired timing.

The laminate according to the present invention comprises:
The peelable adhesive layer;
This provides a laminate that has good adhesion so that it will not peel off during normal use and good releasability so that it can be peeled off whenever desired.

In one embodiment of the laminate according to the present invention, the ratio of the mass of the water-dispersed acrylic resin to the total mass of the water-dispersed acrylic resin and the water-dispersed urethane resin is 10 to 90 mass%.

In one embodiment of the laminate of the present invention, it is for use in a one-component coating film containing a polymerizable unsaturated monomer having an acid anhydride group, or a two-component coating film containing a urethane resin.

In one embodiment of the laminate of the present invention, the peel strength is 3N or more.

In one embodiment of the laminate of the present invention, the peel strength after 80°C/100 hours is 10 N or less.

In one embodiment of the laminate according to the present invention, the peel strength after a 750 MJ Xe test is 10 N or less.

In one embodiment of the laminate according to the present invention,
The peelable adhesive layer;
A design layer and
and the clear layer.

The present invention can provide a peelable adhesive layer that has sufficient adhesion to prevent peeling during normal use and sufficient releasability to allow peeling when desired. The present invention can also provide a laminate that has sufficient adhesion to prevent peeling during normal use and sufficient releasability to allow peeling when desired.

FIG. 1 is a schematic diagram showing an example of a peelable adhesive layer according to the present invention. FIG. 2 is a schematic diagram showing an example of the layer structure of the laminate according to the present invention. FIG. 3 is a schematic diagram showing another example of the layer structure of the laminate according to the present invention. FIG. 4 is a schematic diagram showing another example of the layer structure of the laminate according to the present invention.

The following describes embodiments of the present invention. These descriptions are intended to exemplify the present invention and are not intended to limit the present invention in any way.

In the present invention, two or more embodiments can be combined in any manner.

In the present invention, the paint and the paint composition can be used interchangeably.

Numerical ranges are intended to include the upper and lower limits of the range unless otherwise specified. For example, -80 to 0°C means a range from -80°C to 0°C.

The accompanying drawings are schematic diagrams intended to facilitate understanding of the present invention, and therefore the dimensions and scale of the elements in the drawings are not accurate.

In the present invention, peel strength, peel strength after 80°C/100 hours, and peel strength after Xe test 750 MJ are measured using the methods described in the examples.

In the present invention, resins, solvents, compounds, materials, components, etc. may be used either individually or in combination of two or more.

(Removable adhesive layer)
The peelable adhesive layer according to the present invention comprises:
It is a coating film of paint for adhesive layer,
the adhesive layer coating material is a two-component type consisting of a first agent containing a water-dispersible acrylic resin and a water-dispersible urethane resin, and a second agent containing an isocyanate;
The water-dispersible urethane resin has a glass transition temperature (Tg) of −80 to 0° C.,
the hydroxyl value of the water-dispersible acrylic resin is 40 to 165 mg KOH/g;
The peelable adhesive layer has a ratio (NCO/OH) of the number of moles of isocyanate groups in the isocyanate to the number of moles of hydroxyl groups contained in the first agent of 0.5 to 2.0.

Figure 1 is a schematic diagram showing an example of a peelable adhesive layer according to the present invention.

The peelable adhesive layer is a coating film of adhesive layer paint, and is usually provided in contact with the automobile exterior. After using the laminate of the present invention, the peelable adhesive layer is peeled off from the automobile exterior, allowing the laminate of the present invention to be peeled off from the automobile exterior.

Adhesive Layer Paint The adhesive layer paint that forms the peelable adhesive layer is a two-component type consisting of a first agent and a second agent.

First Agent The first agent contains a water-dispersible acrylic resin and a water-dispersible urethane resin.

Water-dispersible acrylic resins can be obtained, for example, by solution polymerization of a mixture of polymerizable unsaturated monomers. Examples of polymerizable unsaturated monomers that can be used include (meth)acrylic acid alkyl esters, carboxyl group-containing ethylenically unsaturated monomers, and hydroxyl group-containing ethylenically unsaturated monomers.

Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate.

Examples of carboxyl group-containing ethylenically unsaturated monomers include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, maleic anhydride, and fumaric acid.

Examples of hydroxyl group-containing ethylenically unsaturated monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, N-methylolacrylamide, allyl alcohol, and ε-caprolactone-modified acrylic monomers.

Acrylic resins prepared by polymerization may be neutralized with a basic compound, for example, and used in the form of an aqueous solution.

Basic compounds include, for example, organic amines such as monomethylamine, dimethylamine, trimethylamine, triethylamine, diisopropylamine, monoethanolamine, diethanolamine, and dimethylethanolamine.

The water-dispersible acrylic resin has a hydroxyl value of 40 to 165 mg KOH/g. In one embodiment, the water-dispersible acrylic resin has a hydroxyl value (mg KOH/g) of 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 110 or more, 120 or more, 130 or more, 140 or more, 150 or more, or 160 or more. In another embodiment, the water-dispersible acrylic resin has a hydroxyl value (mg KOH/g) of 165 or less, 160 or less, 150 or less, 140 or less, 130 or less, 120 or less, 110 or less, 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, or 50 or less. In yet another embodiment, the water-dispersible acrylic resin has a hydroxyl value (mg KOH/g) of 40 to 130.

The amount of water-dispersed acrylic resin in the first agent may be adjusted as appropriate. In one embodiment, the ratio of the mass of the water-dispersed acrylic resin to the total mass of the water-dispersed acrylic resin and the water-dispersed urethane resin is 10 to 90% by mass. In another embodiment, the ratio of the mass of the water-dispersed acrylic resin to the total mass of the water-dispersed acrylic resin and the water-dispersed urethane resin is 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more. In yet another embodiment, the ratio of the mass of the water-dispersed acrylic resin to the total mass of the water-dispersed acrylic resin and the water-dispersed urethane resin is 90% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less.

Commercially available water-dispersible acrylic resins may also be used.

The water-dispersible urethane resin is preferably a reaction product of a polyol and a polyisocyanate, or may be a reaction product obtained by further reacting a chain extender or a terminal terminator with the reaction product of a polyol and a polyisocyanate.

Examples of polyols include polyether polyols, polyester polyols, polycarbonate polyols, polybutadiene polyols, and polythioether polyols.

Examples of polyether polyols include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Examples of polyester polyols include reaction products of polycarboxylic acids with polyester raw material polyols; ring-opening polymerization products of ε-caprolactone; and copolymers thereof. Examples of polycarboxylic acids include adipic acid, sebacic acid, itaconic acid, maleic anhydride, phthalic acid, and isophthalic acid. Examples of polyester raw material polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, tripropylene glycol, butylene glycol, and neopentyl glycol.

Polycarbonate diol can be prepared, for example, by reacting a polyhydric alcohol (e.g., a diol) with dimethyl carbonate.

Examples of polyhydric alcohols include diols. Examples of diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, and 1,6-hexanediol.

Examples of polyisocyanates include ethylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, p-xylylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, and 1,5-naphthylene diisocyanate.

Examples of chain extenders include ethylene glycol, propylene glycol, 1,4-butanediol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, glycerin, and trimethylolpropane.

Examples of end-capping agents include monoalcohols such as methanol, butanol, octanol, and alkyl alcohol alkylene oxide adducts; and monoamines such as butylamine and dibutylamine.

The Tg of the water-dispersible urethane resin is -80 to 0°C. In one embodiment, the Tg of the water-dispersible urethane resin is -80°C or higher, -70°C or higher, -60°C or higher, -50°C or higher, -40°C or higher, -30°C or higher, -20°C or higher, or -10°C or higher. In another embodiment, the Tg of the water-dispersible urethane resin is 0°C or lower, -10°C or lower, -20°C or lower, -30°C or lower, -40°C or lower, -50°C or lower, -60°C or lower, or -70°C or lower.

Commercially available water-dispersible urethane resins may also be used.

The first agent may contain other resins in addition to the water-dispersible acrylic resin and water-dispersible urethane resin. Examples include polyester resin, polyolefin resin, alkyd resin, epoxy resin, SBR, and NBR. Other components may also include pigments, dispersants, defoamers, UV absorbers, hindered amine light stabilizers, antioxidants, viscosity modifiers, surface conditioners, film-forming aids, rust inhibitors, thickeners, organic solvents, and curing catalysts.

The laminate of the present invention is for use in, for example, one-component coating films containing polymerizable unsaturated monomers having acid anhydride groups, or two-component coating films containing urethane resins.

Examples of polymerizable unsaturated monomers having an acid anhydride group include maleic anhydride, succinic anhydride, itaconic anhydride, citraconic anhydride, phthalic anhydride, oxydiphthalic anhydride, naphthalenedicarboxylic anhydride, trimellitic anhydride, and pyromellitic anhydride.

The second agent contains an isocyanate, such as an aliphatic isocyanate, an aliphatic cyclic isocyanate, an alicyclic isocyanate, an aromatic isocyanate, and biuret and nurate derivatives thereof.

Examples of aliphatic isocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), and trimethylhexamethylene diisocyanate.

Examples of aliphatic cyclic isocyanates include 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, and 1,2-cyclohexane diisocyanate.

Examples of alicyclic isocyanates include isophorone diisocyanate (IPDI) and norbornane diisocyanate methyl.

Examples of aromatic isocyanates include xylylene diisocyanate (XDI), 2,4-tolylene diisocyanate (TDI), and 2,6-tolylene diisocyanate.

The ratio (NCO/OH) of the number of moles of isocyanate groups in the isocyanate to the number of moles of hydroxyl groups contained in the first agent (e.g., hydroxyl groups in the water-dispersible acrylic resin) is 0.5 to 2.0. In one embodiment, the ratio (NCO/OH) is 0.5 or more, 0.6 or more, 0.8 or more, 1.0 or more, 1.2 or more, 1.4 or more, 1.6 or more, or 1.8 or more. In another embodiment, the ratio (NCO/OH) is 2.0 or less, 1.8 or less, 1.6 or less, 1.4 or less, 1.2 or less, 1.0 or less, 0.8 or less, or 0.6 or less.

The thickness of the peelable adhesive layer can be adjusted as needed, but is typically between 20 and 100 μm.

Method for preparing a coating material for a peelable adhesive layer: For example, a water-dispersible acrylic resin and a water-dispersible urethane resin are mixed to prepare a first agent. A second agent containing a polyisocyanate is separately prepared. An organic solvent without a hydroxyl group may be optionally mixed into the second agent. The resulting first and second agents are mixed to prepare a coating material for a peelable adhesive layer. Typically, the first and second agents are mixed immediately before the coating material for a peelable adhesive layer is applied.

Formation of Peelable Adhesive Layer The formation of the peelable adhesive layer is not particularly limited, and for example, a paint for peelable adhesive layer is applied to the substrate, and the coating film is cured to form the peelable adhesive layer.

The amount of paint to be applied for the peelable adhesive layer is not particularly limited and can be set appropriately depending on the performance required of the coating film. For example, it is applied so that the dried coating film thickness is 20 to 100 μm.

The coating method for the peelable adhesive layer paint is not particularly limited, and examples include air spray coating, airless spray coating, rotary atomization coating, and curtain coating. These methods may be combined with electrostatic coating. Coating may be performed multiple times.

After applying the paint for the peelable adhesive layer, the coating is cured. Curing conditions can be set appropriately depending on the amount applied and the composition, for example, at 60°C for about 20 minutes.

(Laminate)
The laminate according to the present invention comprises:
The peelable adhesive layer;
and a clear layer or a design layer.

Figure 2 is a schematic diagram showing an example of the layer structure of a laminate according to the present invention. The laminate 10 in Figure 2 consists of a peelable adhesive layer 1 and a clear layer 2, in that order.

Figure 3 is a schematic diagram showing another example of the layer structure of a laminate according to the present invention. The laminate 10 in Figure 2 consists of a peelable adhesive layer 1 and a design layer 3, in that order.

Figure 4 is a schematic diagram showing another example of the layer structure of the laminate of the present invention. The laminate 10 in Figure 2 consists of a peelable adhesive layer 1, a design layer 3, and a clear layer 2, in that order.

The clear layer is a coating film of a coating composition for a clear layer, and serves to protect the layers located on the vehicle body side of the laminate, such as the peelable adhesive layer and any design layer. The clear layer is usually provided as the outermost layer of the laminate.

A known clear coating composition can be used as the coating composition for the clear layer. For example, the clear coating compositions described in International Publication No. 2020/241342 and Japanese Patent No. 7052119 can be used. Automotive repair paints described in Japanese Patent Laid-Open No. 2022-180115 can also be used.

The coating composition for the clear layer may be either water-based or solvent-based.

The thickness of the clear layer can be adjusted as needed, but is typically between 20 and 100 μm.

Design layer: The design layer is a coating film of a coating composition for a design layer, and is a layer that imparts design to the laminate. As the design layer, a base layer of a conventionally known topcoat coating for automobiles can be used.

As a coating composition for the decorative layer, for example, the coating composition for the decorative layer described in Patent No. 7052119 can be used. Automotive repair paints can also be used.

The coating composition for the decorative layer may be either water-based or solvent-based.

The thickness of the design layer can be adjusted as needed, but is typically between 10 and 100 μm.

One embodiment of the laminate according to the present invention comprises, in order and adjacent to each other, a peelable adhesive layer, a design layer, and a clear layer.

Other Layers The laminate may have other layers in addition to the peelable adhesive layer and the clear layer or the design layer.

In one embodiment of the laminate according to the present invention, the peel strength is at least 3 N. In another embodiment, the peel strength of the laminate is 3 to 10 N.

In one embodiment of the laminate of the present invention, the peel strength after 80°C/100 hours is 10 N or less. In another embodiment, the peel strength of the laminate after 80°C/100 hours is 3 to 10 N.

In one embodiment of the laminate according to the present invention, the peel strength after a 750 MJ Xe test is 10 N or less. In another embodiment, the peel strength of the laminate after a 750 MJ Xe test is 3 to 10 N.

- Method for manufacturing laminate The laminate is manufactured, for example, by a method comprising step (I) of applying a coating material for an adhesive layer to an object to be coated to form a peelable adhesive layer, and step (II) of applying a coating composition for a design layer or a coating composition for a clear layer onto the peelable adhesive layer to form a design layer or a clear layer.

The laminate shown in Figure 4 can be manufactured, for example, by a method comprising step (I) of applying an adhesive layer coating to an article to be coated to form a peelable adhesive layer, step (II) of applying a design layer coating composition onto the peelable adhesive layer to form a design layer, and step (III) of applying a clear layer coating composition onto the design layer to form a clear layer.

(subject to be coated)
The substrate may be flat or three-dimensional. The material of the substrate is not particularly limited. For example, resin or steel plate can be used as the substrate material.

Examples of resins include polyethylene resin, EVA resin, polyolefin resin (polyethylene resin, polypropylene resin, etc.), vinyl chloride resin, styrene resin, polyester resin (including PET resin, PBT resin, etc.), polycarbonate resin, acrylic resin, acrylonitrile butadiene styrene (ABS) resin, acrylonitrile styrene (AS) resin, polyamide resin, acetal resin, phenolic resin, fluororesin, melamine resin, urethane resin, epoxy resin, polyphenylene oxide (PPO), etc.

Examples of steel sheets include metals such as iron, steel, stainless steel, aluminum, copper, zinc, and tin, as well as alloys of these. If necessary, the steel sheets may be subjected to a chemical conversion treatment, and an electrodeposition coating film may further be formed thereon. Examples of chemical conversion treatments include zinc phosphate conversion treatment, zirconium conversion treatment, and chromium oxide conversion treatment. Electrodeposition coating films are formed, for example, by electrodeposition coating using a cationic electrodeposition coating composition or an anionic electrodeposition coating composition.

Examples of substrates include the bodies of cars, trucks, motorcycles, buses, etc.; and bodies with automotive exterior clear coatings.

Examples of clear coatings for automotive exteriors include one-component curing coatings containing polymerizable unsaturated monomers with acid anhydride groups, and two-component curing coatings containing urethane resins.

Process (I)
In step (I), a coating material for a peelable adhesive layer is applied to an article to be coated to form a peelable adhesive layer. The preparation of the coating material for a peelable adhesive layer, application, and formation of the peelable adhesive layer are as described above.

Process (II)
In step (II), a coating composition for a design layer or a coating composition for a clear layer is applied onto the peelable adhesive layer to form a design layer or a clear layer. The application of the coating composition for a design layer may be carried out multiple times.

(Method for preparing coating composition (Y) for decorative layer)
The coating composition for the decorative layer can be a known base coating for automobile exteriors or a base coating for automobile repair, and may be either water-based or solvent-based. The coating composition for the decorative layer may be a curing type or a lacquer type. The coating composition for the decorative layer may further contain a pigment. Examples of pigments include color pigments and luster pigments.

The coating method for the design layer coating composition is not particularly limited, and can be the same as for the adhesive layer coating. The amount of coating for the design layer coating composition is not particularly limited, and is, for example, an amount such that the dry film thickness of the design layer is 10 to 20 μm. The design layer coating composition may be applied multiple times. After applying the design layer coating composition, the coating film is cured. Curing conditions can be set appropriately depending on the amount applied and composition, and are, for example, approximately 20 minutes at 60°C.

The clear layer coating composition can be a known clear coating for automotive exteriors or a clear coating for automotive repair, and can be either water-based or solvent-based. The clear layer coating composition may also contain inorganic particles such as silica.

The method for applying the coating composition for the clear layer is not particularly limited, and may be the same as that for the coating composition for the peelable adhesive layer. The coating of the coating composition for the clear layer may be performed multiple times. The amount of coating of the coating composition for the clear layer is not particularly limited, and may be appropriately set depending on the performance required of the coating film, for example, an amount such that the thickness of the clear coating film after curing is 40 to 60 μm.
After the clear layer coating composition is applied, the coating film is cured under suitable curing conditions, such as at 70° C. for 20 minutes.

Uses of the Laminate The uses of the laminate are not limited and may be selected appropriately. For example, it can be used as a laminate for automobile exteriors for the purpose of changing the color of or protecting the exterior of an automobile.

The present invention will be described in more detail below with reference to examples. However, these examples are intended to illustrate the present invention and are not intended to limit the present invention in any way. In the examples, "parts" refers to parts by mass.

(Preparation of object 1)
An electrodeposition coating composition (Powernics 150, Cation, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was electrodeposited onto a zinc phosphate-treated dull steel plate to a dry coating thickness of 20 μm, followed by heat curing at 160°C for 30 minutes and cooling to prepare a steel plate substrate. An aqueous intermediate coating composition (AR-630-X 8110, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied to the resulting substrate with an air spray gun to a dry film thickness of 25 μm, and the substrate was preheated in an oven set at 80°C for 3 minutes. Subsequently, an aqueous base coating composition (AR-3020-1 202, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied to the substrate with the intermediate coating layer with an air spray gun to a dry film thickness of 15 μm, and the substrate was preheated in an oven set at 80°C for 3 minutes. Furthermore, a clear paint composition (MAC O-1860 Clear, manufactured by Nippon Paint Automotive Coatings) was applied to the substrate having the intermediate coat layer and the base coat so that the dry film thickness was 35 μm. The coating was then heated in an oven set to 140°C for 30 minutes to obtain a coated object 1 having a multi-layer coating film.

(Preparation of clear layer coating composition for substrate 2 )
A mixture of 100 parts of Polyureexcel O-2100 Clear (manufactured by Nippon Paint Automotive Coatings Co., Ltd.) and 9.7 parts of TMK Thinner (diluent, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was prepared as the base component. 38.3 parts of H-2100 (curing agent, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was prepared as the curing agent . This curing agent was mixed with the mixture immediately before painting to prepare a coating composition for the clear layer.

(Preparation of object 2)
A steel plate with an electrodeposition coating was prepared in the same manner as for Substrate 1. Next, a solvent-based intermediate coating composition (OP-30-P DG 8110, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied using an air spray gun to a dry film thickness of 35 μm, and the resulting coating was heated in an oven set at 140°C for 30 minutes. Subsequently, an aqueous base coating composition (AR-3020-1 202, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied using an air spray gun to a dry film thickness of 15 μm to the substrate with the intermediate coating layer, and the resulting coating was preheated in an oven set at 80°C for 3 minutes. Furthermore, the prepared clear layer coating composition was applied to a substrate with an intermediate coating layer and a base layer to a dry film thickness of 30 μm. The resulting coating was then heated in an oven set at 140°C for 30 minutes to obtain Substrate 2 with a multi-layer coating film.

(Preparation of clear layer coating composition for substrate 3 )
A mixture of 100 parts of R-2550-2 (manufactured by Nippon Paint Co., Ltd.) and 30 parts of T-5025 (a diluent, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was prepared as the base resin. 43.4 parts of H-2550 (a curing agent, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was prepared as the curing agent. This curing agent was mixed with the mixture immediately before painting to prepare a coating composition for the clear layer.

(Preparation of object 3)
An aqueous primer coating composition (WB-1200CD-5, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied to a polypropylene substrate using an air spray gun to a dry film thickness of 8 μm, and the coating was preheated in an oven set at 80 ° C for 3 minutes. Subsequently, an aqueous base coating composition (AR-3020-1 202, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied to a substrate having a primer layer using an air spray gun to a dry film thickness of 15 μm, and the coating was preheated in an oven set at 80 ° C for 3 minutes. Furthermore, the prepared clear layer coating composition was applied to a substrate having a primer layer and a base layer to a dry film thickness of 30 μm. The substrate was then heated in an oven set at 120 ° C for 35 minutes to obtain a coated substrate 3 having a multi-layer coating film.

(Preparation of coating composition for clear layer for substrate 4 )
A mixture of 100 parts of R-2550-1 (main agent, manufactured by Nippon Paint Automotive Coatings) and 30 parts of T-505HCL (diluent, manufactured by Nippon Paint Automotive Coatings) was prepared. 44 parts of H-2500 (curing agent, manufactured by Nippon Paint Automotive Coatings) was prepared as a curing agent . This curing agent was mixed with the mixture immediately before painting to prepare a coating composition for the clear layer.

An aqueous primer coating composition (WB-1200CD-5, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied to a polypropylene substrate using an air spray gun to a dry film thickness of 8 μm, and the coating was preheated in an oven set at 80 ° C for 3 minutes. Subsequently, an aqueous base coating composition (AR-3020-1 202, manufactured by Nippon Paint Automotive Coatings Co., Ltd.) was applied to a substrate having a primer layer using an air spray gun to a dry film thickness of 15 μm, and the coating was preheated in an oven set at 80 ° C for 3 minutes. Furthermore, the prepared clear layer coating composition was applied to a substrate having a primer layer and a base layer to a dry film thickness of 30 μm. The substrate was then heated in an oven set at 120 ° C for 35 minutes to obtain a coated substrate 4 having a multi-layer coating film.

Examples 1 to 4
A coating composition for a peelable adhesive layer, a coating composition for a design layer 1, and a coating composition for a clear layer 1 were prepared as follows, and laminates were fabricated.

Preparation of peelable adhesive layer coating material The following materials were charged in this order into a container equipped with a stirrer to obtain a first part of the adhesive layer coating material.
Urethane resin 67 parts (solids)
Acrylic resin 33 parts (solids)
Nopal 3303 (urethane associative thickener, manufactured by San Nopco) 2.0 parts BYK-345 (surface conditioner, manufactured by BYK) 0.6 parts Ion-exchanged water 57.8 parts

Nax E-CUBE WB water-based hardener (manufactured by Nippon Paint Co., Ltd.) was used as the second agent. The resulting first and second agents were mixed immediately before application to prepare the adhesive layer paint.

Design layer coating composition 1 was prepared by mixing 100 parts of nax E-CUBE WB 412 Silent Black (main agent, manufactured by Nippon Paint Co., Ltd.), 50 parts of nax E-CUBE WB 911 S-binder (auxiliary agent, manufactured by Nippon Paint Co., Ltd.), and 45 parts of nax E-CUBE WB R20 standard diluent (diluent, manufactured by Nippon Paint Co., Ltd.).

A mixture of 100 parts of nax E-CUBE WB (2:1) NN Clear (manufactured by Nippon Paint Co., Ltd.) and 30 parts of pure water was prepared as the main component of the clear layer coating composition. 50 parts of nax E-CUBE WB water-based hardener (hardener, also manufactured by Nippon Paint Co., Ltd.) was prepared as the curing agent. This curing agent was mixed with the mixture immediately before painting to prepare clear layer coating composition 1.

(Preparation of laminate)
Preparation of peelable adhesive layer The adhesive layer paint was applied with an air spray gun to the substrate 1. Subsequently, the substrate was heated in an oven set at 60°C for 20 minutes to prepare a peelable adhesive layer.

[0046] The decorative layer coating composition 1 was applied to a substrate having a peelable adhesive layer using an air spray gun, and the substrate was air-dried until the coating no longer adhered to the surface when touched with a finger. This coating and drying process was repeated two more times to form a decorative layer.

Preparation of clear layer: A substrate having a peelable adhesive layer and a design layer was coated with clear layer coating composition 1 using an air spray gun. After leaving the substrate to stand for 30 minutes, the substrate was heated in an oven set to 70°C for 20 minutes to form a clear layer.

(Examples 5 to 7)
Laminates were prepared in the same manner as in Example 1, except that the substrates were changed as shown in Table 1.

(Examples 8 and 9, Comparative Examples 1 to 3)
A laminate was prepared in the same manner as in Example 1, except that the coating composition for the adhesive layer and the film thickness of the peelable adhesive layer were changed as shown in Table 2.

Example 10
A laminate was prepared in the same manner as in Example 1, except that the coating composition for the adhesive layer, the film thickness of the peelable adhesive layer, and the substrate were changed as shown in Table 2.

(Examples 11 to 13)
A laminate was prepared in the same manner as in Example 1, except that the coating composition for the adhesive layer and the film thickness of the peelable adhesive layer were changed as shown in Table 3.

(Examples 14 to 18, Comparative Example 4)
Laminates were prepared in the same manner as in Example 1, except that the coating composition for the adhesive layer and the film thickness of the peelable adhesive layer were changed as shown in Table 4.

(Examples 19 to 22, Comparative Examples 5 and 6)
Laminates were prepared in the same manner as in Example 1, except that the coating composition for the adhesive layer and the film thickness of the peelable adhesive layer were changed as shown in Table 5.

(Example 23)
A laminate was produced in the same manner as in Example 1, except that the paint for the peelable adhesive layer was dried at room temperature until it was dry to the touch, and the film thickness of the peelable adhesive layer was changed.

(Example 24)
A laminate was prepared in the same manner as in Example 1, except that the coating composition for the design layer and the coating composition for the clear layer were changed to the following coating composition for the design layer 2 and coating composition for the clear layer 2, and the film thickness of the peelable adhesive layer was changed.
Preparation of Design Layer Coating Composition 2 100 parts of Nax Real 611 Chinching Black NP (main agent, manufactured by Nippon Paint Co., Ltd.) and 33 parts of Nax StabiR NEO #20 (diluent, manufactured by Nippon Paint Co., Ltd.) were mixed to prepare Design Layer Coating Composition 2.
Preparation of clear layer coating composition 2 A mixture of 100 parts of nax Multi Eco (3:1) 20LX Clear (main agent, manufactured by Nippon Paint Co., Ltd.), 20 parts of nax Multi #20 Standard Urethane Thinner NEO (thinner, manufactured by Nippon Paint Co., Ltd.), and 33 parts of nax Ultra #20 Hardener (hardener, manufactured by Nippon Paint Co., Ltd.) was mixed immediately before painting to prepare clear layer coating composition 2.

Example 25
A laminate was produced in the same manner as in Example 1, except that the coating composition for the design layer was not used, the coating composition for the clear layer was changed to the following coating composition for the clear layer 3, and the film thickness of the peelable adhesive layer was changed.
Preparation of clear layer coating composition 3 A mixture of 100 parts of nax Multi Eco (3:1) Matte Clear (main agent, manufactured by Nippon Paint Co., Ltd.), 50 parts of nax Multi #20 Standard Urethane Thinner NEO (diluent, manufactured by Nippon Paint Co., Ltd.), and 33 parts of nax Ultra #20 Hardener (hardener, manufactured by Nippon Paint Co., Ltd.) was mixed immediately before painting to prepare clear layer coating composition 3.

(Comparative Examples 7 to 18)
A laminate was produced in the same manner as in Example 1, except that the coating material for the adhesive layer was prepared as follows.
Preparation of Comparative Adhesive Layer Paint The following materials were charged in this order into a container equipped with a stirrer to prepare a comparative adhesive layer paint.
Base resin dispersion (Table 7) 100 parts
BYK-345 (surface conditioner, manufactured by BYK) 0.2 parts

(peel strength measurement)
The peel strength between the peelable adhesive layer and the coated substrate was measured using a tensile tester (Shimadzu Autograph AGX-V) equipped with a thermostatic chamber at 20°C under the conditions of a peel angle of 180°, a peel speed of 300 mm/min, and a sample width of 10 mm. The peel strength was measured on three samples, and the average value was calculated and the adhesion was evaluated according to the following evaluation criteria.
Adhesion pass: Peel strength is 3N/cm to 10N/cm
Adhesion failure: Peel strength is less than 3 N/cm or greater than 10 N/cm

(Heat resistance test)
The prepared laminate was heated for 100 hours in an oven at 80° C. After being taken out, it was left to stand at room temperature for half a day or more, and then the peel strength was measured.

(Xe Test)
According to the xenon lamp method of JIS K5600-7-7, the laminate was attached to a Super Xenon Weather Meter SX-75 (manufactured by Suga Test Instruments Co., Ltd.) and subjected to accelerated exposure at an illuminance of 100 W/m ² for 2100 hours.

The present invention has made it possible to provide a peelable adhesive layer that has sufficient adhesion to prevent peeling during normal use and sufficient releasability to allow peeling when desired. The present invention has also made it possible to provide a laminate that has sufficient adhesion to prevent peeling during normal use and sufficient releasability to allow peeling when desired.

The present invention can provide a peelable adhesive layer that has sufficient adhesion to prevent peeling during normal use and sufficient releasability to allow peeling when desired. The present invention can also provide a laminate that has sufficient adhesion to prevent peeling during normal use and sufficient releasability to allow peeling when desired.

1: Peelable adhesive layer 2: Clear layer 3: Design layer 10: Laminate

Claims (8)

A peelable adhesive layer that is provided in contact with the exterior of an automobile and that is peeled off from the exterior ,
the peelable adhesive layer is a coating film of a paint for an adhesive layer,
the adhesive layer coating material is a two-component type consisting of a first agent containing a water-dispersible acrylic resin and a water-dispersible urethane resin, and a second agent containing an isocyanate;
The water-dispersible urethane resin has a glass transition temperature (Tg) of −80 to 0° C.,
the hydroxyl value of the water-dispersible acrylic resin is 40 to 165 mg KOH/g;
A peelable adhesive layer to be provided in contact with the exterior of an automobile and to be peeled off from the exterior, wherein the ratio (NCO/OH) of the number of moles of isocyanate groups in the isocyanate to the number of moles of hydroxyl groups contained in the first agent is 0.5 to 2.0. 2. The peelable adhesive layer according to claim 1, wherein the ratio of the mass of the water-dispersed acrylic resin to the total mass of the water-dispersed acrylic resin and the water-dispersed urethane resin is 10 to 90 mass%. Adjacent in order,
The peelable adhesive layer according to claim 1 or 2 ,
A laminate including a clear layer or a design layer, the peelable adhesive layer being provided in contact with the exterior of an automobile and being peeled off from the exterior . The exterior has a clear coating film,
4. The laminate according to claim 3 , wherein the clear coating film is a one-component coating film containing a polymerizable unsaturated monomer having an acid anhydride group, or a two-component coating film containing a urethane resin. The laminate described in claim 4, having a peel strength of 3 N or more. The laminate described in claim 4, having a peel strength of 10 N or less after 80°C/100 h. The laminate described in claim 4, having a peel strength of 10 N or less after a 750 MJ Xe test. Adjacent in order,
The peelable adhesive layer according to claim 1 or 2 ,
A design layer and
and a clear layer, the peelable adhesive layer being provided in contact with the exterior of an automobile and being peeled off from the exterior .