JP7627345B2 - Flame-retardant interior film - Google Patents

Description

The present invention relates to a flame-retardant interior film in which an adhesive layer and a base layer are laminated in that order, and in particular to a flame-retardant interior film that includes a transparent adhesive layer but has excellent adhesiveness and flame retardancy.

Interior sheets are used for a variety of purposes, including decoration, signage, and interior and exterior decoration. The range of uses for interior films continues to expand, as they can be produced in a wide variety of ways regardless of design, allowing anyone to easily realize a wide range of designs, and they can greatly improve the appearance at low cost.

Interior films are manufactured by laminating multiple layers, such as adhesive layers and base layers, and polymer materials are preferred from the standpoint of cost and processability. In particular, PVC materials, which are widely used as interior film materials, have a fast flame propagation speed when caught on fire and generate toxic gases when burned, so it is necessary to improve their flame retardancy in order to use them for interior decoration.

Meanwhile, interior films are used to improve the appearance of indoor and outdoor surfaces by being attached to them, so they are constantly exposed to external factors such as humidity, temperature, and light. The PVC base layer and the adhesive layer have different expansion and deformation rates, so they repeatedly shrink and expand over time. In particular, the PVC base layer is made into the interior film in a stretched state during the manufacturing process, so it has a higher shrinkage rate than the adhesive layer. As a result, after the interior film is installed, the PVC base layer shrinks, and the adhesive layer, which has a relatively small shrinkage rate, is exposed to the outside.

In the case of flame-retardant interior films, in order to enhance flame retardancy, flame retardants are added not only to the base layer but also to the adhesive layer, which gives the adhesive layer a color such as white. As mentioned above, if the colored adhesive layer becomes exposed due to shrinkage of the base layer after the interior film is installed, this can cause a problem in that the appearance of the installed area is significantly impaired.

In particular, this problem is more prevalent when installing interior film using the butt installation method, in which the ends of the interior film are butted together so that they do not overlap, than when installing interior film using the overlap installation method, in which the ends of the interior film are installed so that they overlap each other, as this impairs the appearance.

In this regard, Patent Document 1 discloses a flame-retardant interior sheet that includes a foamed layer formed by adding a flame retardant to a PVC foam layer. However, the document only discloses an interior sheet that has been given flame retardancy by adding a flame retardant, and does not at all acknowledge the problem of poor appearance caused by the colored flame-retardant adhesive layer being exposed due to shrinkage of the base layer after application of the interior film.

Patent Document 2 relates to an adhesive composition for decorative sheets, which contains a (meth)acrylic acid ester copolymer and a flame retardant, but only discloses that it may contain various known flame retardants, and does not disclose at all the specific flame retardant components of the transparent adhesive layer with excellent flame retardancy and adhesion, or the amounts of each component added and the composition ratio.

Patent Document 3 discloses a non-flammable decorative sheet having an adhesive layer containing a thermoplastic resin sheet of polyvinyl chloride resin, an acrylic acid ester copolymer, a bromine-based flame retardant, antimony trioxide, and a tackifier, but does not disclose the necessity or specific configuration of a flame-retardant interior film having a transparent adhesive layer with excellent flame retardancy and adhesion.

Therefore, there is a need to develop a flame-retardant interior film that has improved flame retardancy while also having excellent adhesion and a transparent adhesive layer that will not damage the appearance even after butting and installation.

Korean Patent Publication No. 10-2019-0070018 Patent No. 6526725 Patent No. 5271770

In conventional flame-retardant interior films, when the adhesive layer is exposed to the outside due to shrinkage of the base layer, a colored adhesive layer appears, which reduces the appearance of the applied area. The purpose of the present invention is to solve this problem.

The present invention aims to provide a flame-retardant interior film that has good flame retardancy while incorporating a transparent adhesive layer into the interior film.

The flame-retardant interior film of the present invention, which solves the above problems, has a structure in which an adhesive layer and a PVC base layer are laminated in that order, the PVC base layer contains one or more selected from the group consisting of antimony oxide, silicate-based flame retardants, and metal hydroxide-based flame retardants, and the adhesive layer contains an acrylic resin and antimony oxide.

In the present invention, the PVC base layer contains antimony oxide, the silicic acid-based flame retardant, and the metal hydroxide-based flame retardant, and the antimony oxide, the silicic acid-based flame retardant, and the metal hydroxide-based flame retardant may be contained in an amount of 10 to 50 parts by weight per 100 parts by weight of polyvinyl chloride contained in the PVC base layer.

In the present invention, the PVC substrate layer includes antimony oxide, the silicic acid-based flame retardant, and the metal hydroxide-based flame retardant, and the antimony oxide, the metal hydroxide-based flame retardant, and the silicic acid-based flame retardant may be added in a weight ratio of 1:1-5:0.2-3.

In the present invention, the antimony oxide and the silicate-based flame retardant may each be independently contained in an amount of 1 to 12.5 parts by weight per 100 parts by weight of polyvinyl chloride, and the metal hydroxide-based flame retardant may be contained in an amount of 1 to 25 parts by weight per 100 parts by weight of polyvinyl chloride.

In the present invention, the adhesive layer may contain 1 to 10 parts by weight of antimony oxide per 100 parts by weight of the acrylic resin.

In the present invention, the adhesive layer may further contain a brominated flame retardant, and the adhesive layer may contain 10 to 30 parts by weight of the brominated flame retardant per 100 parts by weight of the acrylic resin.

In the present invention, the flame-retardant interior film may have a peel strength of 1.80 kg/in or more as measured in accordance with ASTM D3330.

In the present invention, the flame-retardant interior film may have a total heat release (THR) value of 8.0 MJ/ ^m2 or less as measured by a cone calorimeter measurement method in accordance with ISO 5660-1.

In the present invention, the tensile strength of the flame-retardant interior film may be 15 to 30 MPa.

The flame-retardant interior film of the present invention has the advantage that, even when the adhesive layer becomes visible due to shrinkage of the base layer when the interior film is butted together for installation, the adhesive layer is transparent and does not impair the appearance of the installation area.

The present invention has the effect of preventing deterioration in appearance that occurs over time after installation of the interior film while providing good flame retardancy.

The flame-retardant interior film of the present invention has excellent adhesive strength and flame retardancy of the adhesive layer.

1 is a schematic vertical cross-sectional view of a flame-retardant interior film according to an embodiment of the present invention. 1 is a vertical cross-sectional view showing a state in which a base layer of a conventional flame-retardant interior film is deformed due to shrinkage. FIG. 2 is a schematic plan view showing a state in which a conventional flame-retardant interior film is deformed due to shrinkage of the base material layer after being butt-fitted.

Below, each component of the present invention will be described in more detail so that a person having ordinary knowledge in the technical field to which the present invention pertains can easily implement the present invention, but this is merely an example, and the scope of the present invention is not limited to the following content.

To impart flame retardancy to the interior film, flame retardants are added to each of the constituent layers that make up the interior film.

Interior film is used with the purpose of imparting an aesthetic feel by printing the desired design on the top of the base layer and providing an adhesive layer on the bottom of the base layer, and attaching the interior film to the desired location.

There are two methods for installing interior films: overlap installation, in which the outer edges of multiple interior films are installed so that they overlap each other, and abutting installation, in which the outer edges of the interior films are installed so that they do not overlap each other and the ends of the interior films are butted up against each other.

The flame-retardant adhesive layer that makes up the flame-retardant interior film is not transparent but has a color such as white. When the films are overlapped, the adhesive layer is not exposed to the outside. However, when the films are butted together, the individual layers of the interior film shrink at different rates depending on the room temperature and humidity, exposing only the adhesive layer to the outside and damaging the appearance.

Specifically, referring to FIG. 2, which is a vertical cross-sectional view showing the deformation caused by shrinkage of the base layer of a conventional flame-retardant interior film, and FIG. 3, which is a plan view, the PVC base layer is stretched by a calendaring process and then laminated with an adhesive layer to produce an interior film.

The PVC substrate layer 21 is stretched by a calendaring process, laminated with the adhesive layer 11 to produce a flame-retardant interior film 101, and then applied to the attachment surface 1. As time passes after application, the stretched PVC substrate layer 21 shrinks and transforms into a shrunken PVC substrate layer 21'.

The adhesive layer 11, which has a relatively small shrinkage rate and is supported in an adhered state to the adherend surface 1, is maintained without shrinking significantly from its original shape, so that the adhesive layer 11 below the shrunken PVC base layer 21' is exposed to the outside.

The adhesive layer 11 that constitutes the flame-retardant interior film 101 is colored due to the inclusion of a flame retardant, so after the flame-retardant interior film 101 is installed, the PVC base layer 21 shrinks, causing the colored adhesive layer 11 to become visible, resulting in a problem of a reduced aesthetic appearance.

The present invention is intended to solve the above-mentioned problems, and provides a flame-retardant interior film that is transparent and does not impair the aesthetic appearance of the interior film, even if the adhesive layer becomes exposed due to deformation such as shrinkage of the base layer after butt joint construction, and at the same time has excellent adhesive properties in the adhesive layer and in the flame retardancy of the interior film itself.

Below, each component of the flame-retardant interior film according to the present invention will be described in more detail, but this is merely one example for understanding the technical concept of the present invention, and the scope of the invention is not limited by the following description.

PVC substrate layer containing polyvinyl chloride is manufactured into a film shape in a stretched state by a calendaring process during processing, and since it is laminated with an adhesive layer in a stretched state, the substrate layer naturally shrinks over time, which can cause a problem. When the stretched polyvinyl chloride substrate layer shrinks, there can be a problem that the adhesive layer appears in an adhered state on the adherend surface.

When an interior film containing a stretched polyvinyl chloride base layer and an adhesive layer is installed using the butt-fit installation method as described above, the ends of the stretched base layer are attached so as to butt against each other when installed. However, over time or in response to environmental changes (temperature, humidity, etc.) around the installation area, the stretched base layer shrinks, exposing the adhesive layer underneath.

The flame-retardant adhesive layer of the flame-retardant interior film is colored, and as the base layer shrinks, the colored flame-retardant adhesive layer becomes exposed, causing a significant deterioration in appearance.

This is because the flame-retardant adhesive layer becomes opaque when an excessive amount of flame retardant is added to ensure the desired level of flame retardancy.

The present invention is intended to solve such problems, and aims to solve the problem of appearance damage that occurs when interior films are butted together by introducing an adhesive layer of the above-mentioned composition, as described above, to introduce a transparent adhesive layer that has excellent adhesion and good flame retardancy.

Specifically, in the present invention, the PVC substrate layer contains polyvinyl chloride and a flame retardant. It contains polyvinyl chloride to produce a material having the shape and predetermined strength of the substrate layer, and contains at least one selected from the group consisting of antimony oxide, silicate-based flame retardants, and metal hydroxide-based flame retardants to impart flame retardancy.

The PVC substrate layer is manufactured in a layered form using a PVC substrate layer forming composition. For example, the substrate layer can be formed by applying a substrate layer forming composition containing polyvinyl chloride, an organic flame retardant, an inorganic flame retardant, an auxiliary flame retardant, a plasticizer, a heat-resistant plasticizer, a stabilizer, a processing aid, an impact modifier, etc.

The substrate layer may have a thickness of 50 to 150 μm (micrometers), and preferably has a thickness of 80 to 150 μm (micrometers).

If the thickness is thinner than the above range, the strength of the flame-retardant interior film will be reduced, making it unsuitable for use as an interior film, and if the thickness is thicker than the above range, it will be difficult to apply to curved areas.

The PVC substrate layer may contain antimony oxide, a silicate-based flame retardant, and a metal hydroxide-based flame retardant, and the antimony oxide, the silicate-based flame retardant, and the metal hydroxide-based flame retardant may be contained in an amount of 10 to 50 parts by weight per 100 parts by weight of polyvinyl chloride.

If an amount exceeding the above-mentioned content is added, the viscosity of the base layer-forming composition increases, making it difficult to process the composition into a layer. In addition, the transparency of the adhesive layer decreases, and the conventional problem of impairing the appearance when the adhesive layer is exposed to the outside remains.

The total content of the flame retardants is within the range described above, and each flame retardant is added in a ratio that satisfies the above content ratio.

More specifically, the antimony oxide, the metal hydroxide-based flame retardant, and the silicic acid-based flame retardant may be added in a weight ratio of 1:1-5:0.2-3.

Preferably, they may be added in a weight ratio of 1:1-4.5:0.4-1.2.

When the silicate-based flame retardant is added in an amount greater than the above ratio, problems arise such as increased production costs, decreased film strength, and decreased processability. When added in an amount less than the above ratio, problems arise such as decreased flame retardant performance due to high heat release.

On the other hand, if the metal hydroxide flame retardant is added in an amount greater than the above ratio, there is a problem that the viscosity of the composition for forming the PVC base layer increases, making it difficult to form into a film, and there is a problem that the shrinkage rate of the base layer increases with temperature changes during production into an interior film, resulting in a deterioration in the quality of the interior film. If the metal hydroxide flame retardant is added in an amount less than the above ratio, there is a problem that the flame retardant performance decreases.

On the other hand, the antimony oxide may specifically be antimony trioxide (Sb ₂ O ₃ ), antimony pentoxide (Sb ₂ O ₅ ), etc., and is preferably antimony trioxide.

Antimony trioxide is a white, odorless powder that is primarily used as a flame retardant for plastics, polyester polymerization catalysts, and clarifying agents for removing bubbles in the glass manufacturing process. Antimony trioxide for flame retardant use can be added in an appropriate ratio with halogen-based flame retardants depending on the type of plastic to increase the flame retardant effect.

Specifically, antimony oxide helps the chlorine radicals formed in the PVC substrate layer to capture OH and H radicals and prevent combustion. When using PVC resin as in the present invention, the antimony oxide retains halogen radicals to maintain or strengthen the flame retardant performance, preventing the chlorine radicals generated by the combustion of the PVC substrate layer from easily scattering into the air and reducing the flame retardant performance, thereby improving the flame retardant performance of the PVC substrate layer.

In the present invention, the antimony oxide may be contained in an amount of 1 to 12.5 parts by weight per 100 parts by weight of the polyvinyl chloride.

The silicate-based flame retardant is a silicate compound, and may include, for example, a silicate compound such as sodium silicate, calcium silicate, or magnesium silicate.

The silicic acid-based flame retardant forms a glass film on the carbonized film formed during combustion, strengthening the carbonized film and preventing active radicals that induce combustion from coming into contact with the dematerialized material, thereby preventing combustion. In the present invention, the silicic acid-based flame retardant may be included in an amount of 1 to 12.5 parts by weight per 100 parts by weight of the polyvinyl chloride.

On the other hand, the metal hydroxide flame retardant refers to a metal hydroxide salt, and for example, flame retardants such as magnesium hydroxide, aluminum hydroxide, and calcium hydroxide can be used.

The metal hydroxide flame retardant prevents combustion by generating water during combustion and lowering the temperature of the combustion site, thereby improving flame retardant performance. In the present invention, the metal hydroxide flame retardant may be included in an amount of 1 to 25 parts by weight per 100 parts by weight of the polyvinyl chloride.

However, the amount of each type of flame retardant added within the range of the total content and addition ratio of the flame retardants contained in the PVC base layer is merely an example, and the actual amount added can be appropriately added within the above ratio range within the range of the total content and addition ratio.

The present invention provides a flame-retardant interior film that maximizes the flame-retardant performance of the PVC base layer by simultaneously adding the above-mentioned flame retardants in a manner that satisfies the specified content and ratio.

In addition to the flame retardant, the PVC substrate layer may further contain other components such as plasticizers and heat stabilizers.

Other components can be added in appropriate amounts as needed.

Specifically, the plasticizer may be, for example, a phthalate plasticizer, an adipate plasticizer, a trimellitate plasticizer, or an ester plasticizer.

Thermal stabilizers that can be used include Cd/Ba/Zn-based thermal stabilizers, Cd/Ba-based thermal stabilizers, Ba/Zn-based thermal stabilizers, Ca/Zn-based thermal stabilizers, Na/Za-based thermal stabilizers, Sn-based thermal stabilizers, Pb-based thermal stabilizers, Cd-based thermal stabilizers, and Zn-based thermal stabilizers, and impact modifiers that can be used include MBS impact modifiers, acrylic impact modifiers, and the like. It is not necessary to use only one of each component, and one or more appropriate components can be used as necessary.

However, since the above components are not essential components, other additional components can be added as necessary without departing from the purpose of the present invention, or the base layer can be formed without the above components.

Polyvinyl chloride is a type of thermoplastic plastic that is excellent in processability and durability, but is weak against heat. In the present invention, a flame retardant is added to the polyvinyl chloride to form the base layer, thereby compensating for the disadvantage of polyvinyl chloride being weak against heat.

Meanwhile, the polyvinyl chloride is an additive polymer polymerized using vinyl chloride as a monomer, and in the present invention, it is preferable to use polyvinyl chloride having a degree of polymerization in the range of 500 to 2000. More preferably, polyvinyl chloride having a degree of polymerization of 800 to 1200 can be used.

When polyvinyl chloride having a degree of polymerization higher than the above range is used, there are problems that it is difficult to process and is too hard, and when polyvinyl chloride having a degree of polymerization lower than the above range is used, there are problems that durability and processing stability are reduced.

The adhesive layer includes an acrylic resin and an antimony oxide, and the adhesive layer includes an acrylic resin for imparting adhesion to the adhesive layer, and a flame retardant for imparting flame retardancy, and includes antimony oxide.

The adhesive layer is produced in a layered form using an adhesive layer-forming composition. For example, an adhesive layer can be formed by applying an adhesive layer-forming composition containing an acrylic resin, a flame retardant, a solvent, a curing agent, and a tackifier.

The adhesive layer may have a thickness of 20 to 60 μm (micrometers), preferably 30 to 50 μm (micrometers).

If the thickness is thinner than the above range, there is a problem of poor adhesion, and if the thickness is thicker than the above range, there is a problem that when the adhesive layer-forming composition is used to apply the adhesive layer in layers, curing is slow, and it is difficult for the adhesive layer to maintain sufficient strength and adhesion.

The adhesive layer may contain 1 to 10 parts by weight of antimony oxide per 100 parts by weight of the acrylic resin.

The adhesive layer forming composition for forming the adhesive layer may contain 1 to 10 parts by weight of antimony oxide, 100 to 200 parts by weight of a solvent, 0.1 to 10 parts by weight of a curing agent, and 1 to 15 parts by weight of a tackifier, relative to 100 parts by weight of the acrylic resin.

Specific examples of the solvent include toluene, xylene, ethyl acetate (EAc), methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK). If necessary, a mixed solvent obtained by mixing appropriate solvents together can be used.

On the other hand, the curing agent can be of any type, as long as it enables the pressure-sensitive adhesive-forming composition to be formed into an adhesive layer and can function as a curing agent by reacting with the acrylic resin. For example, epoxy-based, chelate-based, melamine-based, isocyanate-based, aziridine-based, and oxazoline-based curing agents may be used, and one or more types of curing agents may be used in combination as necessary.

The tackifier is a component added to increase the adhesive strength of the adhesive layer, and can improve the adhesive strength, and can be used without any particular limitation as long as it is used in the relevant technical field, such as rosin ester, terpene phenol, petroleum-based _C6 resin, petroleum-based _C9 resin, etc., and one or more appropriate tackifiers can be used in combination as necessary.

In the flame-retardant interior film according to the present invention, the adhesive layer may have a light transmittance of 70% or more. Preferably, it may be 75% or more.

If the transmittance is lower than the above range, as intended by the present invention, when the adhesive layer is exposed due to shrinkage of the base layer, the color of the adhesive layer will significantly impair the appearance.

This can cause problems, particularly when installing interior film using a butt joint construction as described above, as the color of the adhesive layer is exposed, resulting in a significant deterioration in appearance.

Acrylic Resin The acrylic resin can be used without any particular limitation as long as it is capable of forming an adhesive layer and has sufficient adhesive strength so as to function as an interior film.

The acrylic resin refers to an adhesive obtained by polymerizing acrylate and methacrylate monomers. For example, the acrylic resin may contain functional groups such as hydroxyl groups or carboxyl groups, such as hydroxyalkyl (meth)acrylate, or may be copolymerized with nitrogen-containing (meth)acrylic ester monomers.

The acrylic resin may have a solids content of 5 to 50%, preferably 10 to 45%.

If the solids content is greater than the above-mentioned amount, the viscosity of the adhesive increases significantly, making it difficult to apply. If the solids content is less than the above-mentioned amount, it is difficult to form an adhesive layer of a certain thickness or more.

Antimony Oxide: Conventional flame retardants added to the adhesive layer of flame-retardant interior films make the adhesive layer opaque, which causes problems such as the substrate layer shrinking due to changes in the external environment or the opaque adhesive layer being exposed when the interior film is removed after use, marring the appearance.

Adhesive layers that are primarily opaque or white in color have problems that arise when the inorganic flame retardant content is excessive, and problems with not being able to ensure sufficient flame retardancy when the inorganic flame retardant content is significantly reduced.

The objective of the present invention is to solve these problems by simultaneously ensuring the adhesive layer's adhesion and flame retardancy, while still ensuring the transparency of the adhesive layer and maintaining the original functionality of the flame-retardant interior film.

As a result, the adhesive layer of the flame-retardant interior film of the present invention contains a predetermined content of antimony oxide to maintain the transparency of the adhesive layer, and the PVC base layer contains predetermined contents of antimony oxide, silicate-based flame retardant, and metal hydroxide-based flame retardant, making it possible to provide an interior film with a transparent adhesive layer and excellent flame retardancy.

Specifically, the antimony oxide can refer to the composition of the antimony oxide added to the PVC substrate layer. The antimony oxide contained in the adhesive layer may be the same as or different from the antimony oxide in the PVC substrate layer.

The adhesive layer contains antimony oxide, which allows the adhesive layer to simultaneously ensure transparency and flame retardancy. For example, when an inorganic flame retardant other than antimony oxide is used, there is a problem that it is difficult to ensure sufficient flame retardancy by adding only a small amount, and when another inorganic flame retardant is used in the same amount or in an excessive amount, there is a problem that it is difficult to ensure the transparency of the adhesive layer, or that the viscosity of the adhesive layer-forming composition used to form the adhesive layer is high, resulting in reduced coatability.

The content of the antimony oxide contained in the adhesive layer of the flame-retardant interior film according to the present invention may be 1 to 10 parts by weight per 100 parts by weight of the acrylic resin. Preferably, it may be 2 to 8 parts by weight.

If an amount exceeding the above content is added, the viscosity of the adhesive layer-forming composition increases, making it difficult to process the composition into a layer. In addition, the transparency of the adhesive layer decreases, and the adhesive layer is exposed to the outside, resulting in the same problem as in the past, which is that the appearance is impaired.

If it is added in an amount less than the above amount, there is a problem that sufficient flame retardancy cannot be ensured.

Other Flame Retardants The adhesive layer may contain other flame retardants in addition to antimony oxide to improve flame retardancy.

Flame retardants that can be added include halogen-based flame retardants. Preferably, bromine-based flame retardants can be added.

The addition of the brominated flame retardant has the advantage that the adhesive strength of the adhesive layer does not decrease and transparency can be maintained.

The other flame retardants can be used without any particular restrictions as long as they are known flame retardants, but since the adhesive layer contained in the interior film of the present invention must have excellent flame retardancy and adhesiveness as well as transparency, they can be appropriately added within a range that does not reduce these properties.

In particular, the other flame retardants refer to all other flame retardants except for antimony oxide that are added to the adhesive layer, and can be added appropriately within the scope of the present invention, regardless of whether they are additive flame retardants, reactive flame retardants, inorganic flame retardants, organic flame retardants, etc.

For example, organic flame retardants may include phosphorus-based flame retardants, nitrogen-based flame retardants, halogen-based flame retardants, bromine-based flame retardants, etc. However, inorganic flame retardants other than antimony oxide added to the adhesive layer are referred to as other flame retardants, and may be added within the scope of the present invention.

In detail, the adhesive layer further contains a brominated flame retardant as another flame retardant, and the brominated flame retardant can be added in an amount of 10 to 30 parts by weight per 100 parts by weight of the acrylic resin.

Like the adhesive layer, the PVC substrate layer may further contain other flame retardants that can improve flame retardancy.

Other flame retardants in the PVC base layer can be any known flame retardant without any particular restrictions, and unlike the adhesive layer, there is no restriction on the type of flame retardant to be transparent, so they can be added as appropriate within the scope of the purpose of the present invention.

Therefore, in the case of other flame retardants in the PVC base layer, the content is not particularly limited, but can be added in various amounts within a range that does not deteriorate the properties required for the base layer, such as the properties of the base layer-forming composition being deteriorated to the point that the base layer cannot be formed in the calendaring process or the rigidity is reduced.

The other flame retardants refer to all other flame retardants except for the antimony oxides, silicate-based flame retardants, and metal hydroxide-based flame retardants in the PVC base layer, and can be appropriately added within the range intended by the present invention, regardless of whether they are additive flame retardants, reactive flame retardants, inorganic flame retardants, organic flame retardants, etc.

For example, organic flame retardants may include phosphorus-based flame retardants, nitrogen-based flame retardants, halogen-based flame retardants, and bromine-based flame retardants, while inorganic flame retardants may include metal compounds and inorganic phosphorus-based flame retardants.

In addition, the flame-retardant interior film according to the present invention may include additional layers without departing from the scope of the present invention. Additional layers such as a printing layer and a surface coating layer may be configured in various ways.

The present invention aims to solve the problems that occur after conventional flame-retardant interior film butt joint installation, and it is possible to add additional layers and additives within the scope of the inherent functions of flame-retardant interior film, such as adhesion and flame retardancy.

Specifically, the flame-retardant interior film according to the present invention is characterized in that it has a peel strength of 1.80 kg/in or more as measured in accordance with ASTM D3330, and a total heat release (THR) value of 8.0 MJ/m2 or ^less as measured by a cone calorimeter measurement method in accordance with ISO 5660-1.

The peel strength corresponds to a level of physical properties suitable for commercialization as an interior film product, and the flame retardant performance meets the standards for commercialization as a flame-retardant interior film product. The flame-retardant interior film of the present invention is characterized in that the transparent adhesive layer has sufficient adhesiveness and flame retardancy.

In addition, the flame-retardant interior film according to the present invention may have a tensile strength of 15 to 30 MPa. Preferably, it may be 20 to 25 MPa.

If the above range is met, the film can be considered to have the flexibility and durability required for an interior film, and these physical properties are attributable to the physical properties of the PVC base layer of the interior film.

Below, an embodiment of the present invention will be described in detail so that a person having ordinary skill in the technical field to which the present invention pertains can easily implement the present invention. However, this is merely an example, and the scope of the present invention is not limited to the following content.

[Production Example]
Interior films were manufactured based on the following Tables 1 and 2.

The substrate layer was made by mixing a composition containing polyvinyl chloride, and then using a calendaring method to produce a film-like stretched polyvinyl chloride substrate layer with a thickness of 100 μm (micrometers).

A transparent PVC film was laminated onto one side of the manufactured base layer to produce a laminate.

An acrylic resin copolymerized with butyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, and acrylic acid was mixed with ethyl acetate as a solvent, and a flame retardant was added.

The composition was coated onto a release paper and dried at 110°C for 3 minutes to produce a flame-retardant adhesive layer. The thickness after drying was approximately 35 μm (micrometers).

The adhesive layer produced was laminated with the laminate to produce an interior film.

[Experimental Example]
The produced interior film was evaluated for physical properties as follows, and the results are shown in Table 3.

1. Light Transmittance Test of Adhesive Layer The adhesive layer prepared in the above Preparation Example was coated on a transparent PET sheet, and the transmittance of the adhesive was measured.

The transmittance was evaluated by irradiating light with a wavelength of 550 nm using Haze-gard plus (manufacturer: BYK Gardner GmbH/AB NEXO).

2. Measurement of Total Heat Release Amount In order to evaluate the flame retardant performance of the interior film, an evaluation was carried out in accordance with the cone calorimeter measurement method (ISO-5660-1).

Each interior film was prepared as a standardized sample and then evaluated. If the total heat release for each interior film was 8.0 MJ/ ^m2 or less, it was rated as "good" and if it was 7.2 MJ/m2 or ^less , it was rated as "excellent."

3. Peel Force According to ASTM D3330, an interior film was attached to a SUS substrate (2 kg, 5 reciprocating motions), and then peeled off at a speed of 300 mm/min to measure the peel force.

4. Tensile Strength The tensile strength was measured using a tensile strength tester (device name, company name).

Referring to Table 3, it can be seen that the adhesive layer of the example is more transparent than that of the comparative example, the adhesive layer has better adhesive strength, and the tensile strength of the interior film itself is also better.

Specifically, in the cases of Comparative Examples 7 and 11, the transparency of the adhesive layer is poor, and the problem that the present invention aims to solve is that after the interior film is butted and installed, the PVC base layer shrinks due to changes in the installation environment over a long period of time (such as temperature and humidity changes), exposing the adhesive layer, and the opaque color of the adhesive layer is exposed to the outside, damaging the appearance.

On the other hand, in the case of Comparative Examples 1 to 4, it can be seen that the adhesive layer has a high light transmittance and is therefore transparent, but in contrast, it can be seen that the total heat release of the interior film is high and the flame retardant properties are significantly inferior.

Comparative examples 5 and 9 have the lowest adhesive strength, but this is because the adhesive layer contains an excessive amount of curing agent and tackifier, which results in poor adhesiveness.

In the cases of Comparative Examples 6 and 10, it can be seen that the tensile strength is low, but this is because an excessive amount of solids is added to the substrate layer, which significantly reduces the flexibility of the substrate layer that constitutes the interior film.

In this way, it can be confirmed that the flame-retardant interior film of the embodiment has a transparent adhesive layer, is suitable for use in butt joint construction, has excellent adhesion of the adhesive layer and flame retardancy of the flame-retardant interior film itself, and meets the tensile properties required for an interior film.

Claims (5)

It has a structure in which an adhesive layer and a PVC base layer are laminated in this order,
The PVC substrate layer contains antimony oxide, a silicic acid-based flame retardant, and a metal hydroxide-based flame retardant ,
The adhesive layer contains an acrylic resin , an antimony oxide , a curing agent, a bromine-based flame retardant, and a tackifier ,
The antimony oxide, the metal hydroxide-based flame retardant, and the silicic acid-based flame retardant of the PVC substrate layer are added in a weight ratio of 1:1 to 4.5:0.4 to 1.2;
The antimony oxide of the PVC substrate layer is contained in an amount of 1 to 12.5 parts by weight per 100 parts by weight of polyvinyl chloride,
The adhesive layer contains, relative to 100 parts by weight of the acrylic resin, 0.1 to 2 parts by weight of the curing agent, 10 to 20 parts by weight of the bromine-based flame retardant, 1 to 10 parts by weight of the antimony oxide, and 1 to 5 parts by weight of the tackifier . The flame-retardant interior film according to claim 1, wherein the antimony oxide, the silicic acid-based flame retardant, and the metal hydroxide-based flame retardant are contained in an amount of 10 to 50 parts by weight per 100 parts by weight of the polyvinyl chloride contained in the PVC base layer. The flame-retardant interior film according to claim 1, wherein the silicate -based flame retardant is contained in an amount of 1 to 12.5 parts by weight per 100 parts by weight of polyvinyl chloride, and the metal hydroxide-based flame retardant is contained in an amount of 1 to 25 parts by weight per 100 parts by weight of polyvinyl chloride. The flame-retardant interior film is
2. The flame-retardant interior film according to claim 1, having a total heat release (THR) value of 8.0 MJ/ ^m2 or less as measured by a cone calorimeter measurement method in accordance with ISO 5660-1. 2. The flame-retardant interior film according to claim 1, wherein the adhesive layer has a light transmittance of 70% or more.

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