WO2008091045A1

WO2008091045A1 - Interior product having transfer-printed base layer and process for preparing the same

Info

Publication number: WO2008091045A1
Application number: PCT/KR2007/004490
Authority: WO
Inventors: Jong-Bum Kim; Seung-Baik Nam; Sung-Gyu Lee
Original assignee: Lg Chem, Ltd.
Priority date: 2007-01-24
Filing date: 2007-09-18
Publication date: 2008-07-31
Also published as: KR20080069896A; KR100918559B1

Abstract

Disclosed herein is an interior product comprising a transfer-printed base layer and a process for manufacturing the interior product. According to the interior product, an aqueous primer layer is formed on a base layer as a core layer and transfer printing is performed on the surface of the primer layer to form a printed layer so that the adhesion of the core layer to the printed layer is enhanced, and elaborate surface image effects are diversely realized. Since the interior product of the present invention comprises a printed layer formed by directly performing transfer printing on the base layer, it can secure a surface layer at a low cost, reduce color difference between final products and is free of surface defects as compared to interior products using a veneer as a surface layer.

Description

INTpRIOR PRODUCT HAVING TRANSFER-PRINTED BASE LAYER AND PROCESS FOR PREPARING THE SAME

Technical Field

The present invention relates to an interior product comprising a transfer- printed base layer and a process for manufacturing the interior product. More specifically, the present invention relates to an interior product comprising a base layer and an aqueous primer layer formed on the base layer wherein transfer printing is performed on the surface of the primer layer to form a printed layer so that the adhesion of the base layer to the printed layer is enhanced, elaborate surface image effects are diversely realized and superior physical properties (e.g., dimensional stability) are imparted to the interior product.

Background Art

Floorings, one of major interior products, are classified into plywood floorings and laminated floorings depending on the base type used. Meanwhile, floorings are classified into tongue and groove (T & G) processed adhesion-type floorings and click-processed non-adhesion-type floorings depending on the processing method (i.e., depending on whether to use an adhesive agent).

Plywood floorings (for under-floor heating systems) are formed using a veneer having a thickness of 0.3 to 0.8 mm. In particular, wood floorings are formed using a veneer having a thickness of 2 mm or more. Laminated floorings are formed using a melamine-impregnated paper such as a low-pressure melamine

(LPM)-impregnated paper or a high-pressure melamine (HPM)-impregnated paper.

To impart wood patterns to melamine-impregnated papers used for laminated floorings, the melamine-impregnated papers are formed by performing gravure-printing on a given paper to produce a pattern paper and impregnating a melamine resin into the pattern paper. Melamine-impregnated papers are classified into LPMs and HPMs depending on the pressure applied and whether to use an adhesive agent.

Conventional floorings for under-floor heating systems are manufactured by laminating a natural veneer on a water-resistant plywood and treating the natural veneer by surface coating. Such conventional floorings for under-floor heating systems have advantages in that the natural texture of wood is maximized and superior dimensional stability against heat and moisture is ensured due to the use of a water-resistant plywood. However, since a low-density veneer and a 5 low-density water-resistant plywood (0.6-0.8 g/cm³) are used, conventional floorings for under-floor heating systems suffer from poor scratch resistance (0.5- 3.0 N, as measured by scratching the surface of the floorings using a diamond chip) and poor impact resistance (10-20 cm, as measured by dropping a metal ball weighing 225g onto the surface of the floorings) although UV coating is 0 performed on the surface of the floorings. Poor resistance to scratch and impact of conventional floorings generally causes many problems. For example, when a consumer drops a household appliance by mistake or transports a heavy object on the surface of conventional floorings, damage to the surface of the flooring may occur. In addition, a low thermal conductivity of conventional floorings leads to

L 5 an energy loss. Besides, the use of veneers as natural materials causes the price of conventional floorings to rise, involves much color difference between final flooring products and leads to occurrence of surface defects e.g., cracks, dead knots, gums or knife traces.

On the other hand, conventional laminate floorings are manufactured by 0 sequentially laminating a printed layer and a melamine-impregnated overlay sheet on a high-density fiberboard (HDF) layer as a base layer and laminating a balance layer under the base layer. Such conventional laminate floorings have a rigid surface, compared to water-resistant plywood floorings for under-floor heating systems. However, since the surface of conventional laminate 5 floorings is composed of a thermosetting melamine resin, it is sensitive to moisture and is highly likely to be brittle, thus giving a feeling of coldness to consumers. In addition, when a sharp or heavy object having a load exceeding a predetermined value drops onto conventional laminate floorings, the impact site is partly damaged, e.g., broken or indented. Besides, conventional 0 laminate floorings have poor physical properties e.g., moisture resistance, heat resistance, dimensional stability and thickness expansion rate, compared to water-resistant plywood floorings for under-floor heating systems using a plywood, as a core, which is manufactured by adhering a plurality of veneers to adjacent veneers at right angles. Furthermore, since the surface of 5 conventional laminate floorings is artificially printed, the laminate floorings exhibit inferior natural texture of wood when compared to conventional water- resistant plywood floorings for under-floor heating systems.

Disclosure of Invention 5 Technical Problem

The present invention has been made in view of the above-mentioned problems of the conventional interior products, and it is one aspect of the present invention to provide an interior product comprising a base layer and an aqueous

L 0 primer layer formed on the base layer wherein transfer printing is performed on the surface of the primer layer to form a printed layer so that the adhesion of the base layer to the printed layer is enhanced, the elaborate surface image is diversely expressed, and the dimensional stability of the interior product is greatly improved.

L 5 It is another aspect of the present invention to provide an interior product comprising a surface coating layer in which surface physical properties, such as scratch resistance and indentation resistance, of the interior product are greatly improved by the addition of a material selected from glass chops, ceramics, nano- sized inorganic materials, silica and mixtures thereof to the surface coating layer, 0 thereby protecting the surface of the interior product against damage, e.g., indentation, breakage and scratch, caused by a heavy or sharp object.

It is yet another object of the present invention to provide a process for manufacturing an interior product with improved workability and productivity which comprises forming a primer layer, a transfer-printed layer and a surface 5 coating layer under respective optimum conditions.

Technical Solution

In accordance with an aspect of the present invention for achieving the 0 above aspect, there is provided an interior product comprising a base layer, a primer layer and a printed layer laminated in this order from the bottom.

The interior product may be utilized in applications including floorings, wall panels, louvers, ceilings and the like.

According to one embodiment of the present invention, the base layer 5 may be plywood. In this case, since transfer printing is directly performed on the plywood, the interior product has advantages of low-price, little color difference between products and elimination of surface defects e.g., veneer cracks, dead knots or knife trace, when compared to general wood floorings and plywood floorings for under-floor heating systems. The greatest advantage of the interior product according to the present invention is superiority in physical properties such as moisture resistance, heat resistance, dimensional stability and thickness expansion rate owing to superior physical properties of the plywood, compared to laminate floorings, which are manufactured by sequentially laminating a printed layer and a melamine-impregnated overlay sheet on a high-density fiberboard as a base layer. In addition, the interior product according to the present invention is advantageous in that the natural beauty of wood is faithfully imparted to the surface of the interior product on which transfer printing is elaborately realized.

According to another embodiment of the present invention, the base layer may be a composite base having a multilayer structure in which two or more types of wood materials are laminated. By forming an aqueous primer layer on the composite base and performing transfer-printing on the primer layer, the natural beauty of wood can be faithfully realized and a desired color and pattern can be obtained. The interior product of the present invention can ensure higher moisture resistance (e.g., dimensional stability or thickness expansion rate) than that of a high-density fiberboard (HDF). The interior product is advantageous in terms of improved moisture resistance and wood's inherent beautiful appearance, since a veneer, one part of the interior product, rather than high-density fiberboard (HDF), is exposed to the bottom of the interior product.

According to another embodiment of the present invention, the base layer may be composed of at least one selected from a wood, a veneer, a particle board, a medium density fiberboard (MDF), a high density fiberboard (HDF), a high pressure laminate (HPL), a low pressure laminate (LPL), an oriented strand board (OSB), a flake board, a kenaf board, a corrugated cardboard and a paper.

To enhance the strength of the surface layer, the interior product of the present invention may further comprise a reinforcing layer interposed between the primer layer and the base layer. The reinforcing layer may be composed of a paper, a synthetic-resin sheet, or the like.

The wood materials used to form the base layer as the composite base are composed of two or more materials selected from a wood, a veneer, a particle board, MDF, HDF, HPL, LPL, OSB, a flake board, a kenaf board, a corrugated cardboard and a paper.

The composite base may have a multilayer structure in which two or more wood materials are laminated. For example, first, the composite base may have a multilayer structure including a veneer, a fiberboard and a veneer laminated in this order from the top. Second, the composite base may have a multilayer structure including a veneer and a fiberboard laminated in this order from the top. Third, the composite base may have a multilayer structure including a kenaf board, a fiberboard and a kenaf board laminated in this order from the top. Fourth, the composite base may have a multilayer structure including a veneer, a plywood and a veneer laminated in this order from the top. Fifth, the composite base may have a multilayer structure including a fiberboard, a veneer, a fiberboard, a veneer and a fiberboard laminated in this order from the top. Of these multilayer structures, most preferred is a veneer/HDF/veneer structure which is low-priced and exhibits substantially equivalent physical properties, when compared to plywoods.

According to another embodiment of the present invention, the base layer may be an inorganic board or a synthetic resin panel. The use of the inorganic board or synthetic resin panel as the base layer is advantageous in that mechanical properties and surface strength of interior products are improved due to high density, and dimensional variation or shape deformation of boards caused by moisture is reduced. Meanwhile, the use of the inorganic board or synthetic resin panel as a flooring is advantageous in that heating costs are reduced due to high thermal conductivity. Besides, the use of the inorganic board as the base layer also imparts fire retardancy to the interior product.

According to the present invention, a backing layer may be further formed under the base layer to reinforce structural stability of the interior product. The backing layer is formed by coating the bottom surface of the base layer with at least one selected from a paper, a metal foil, a ultraviolet (UV) curable surface- treating agent, a heat curable surface-treating agent, a synthetic resin, wax, a silicone-based water-repellent agent, a silicone-based waterproofing agent, and the like. The formation of the backing layer on the bottom surface of the base layer cjan solve the problem of deformation caused by a variation in humidity. It is preferred that the primer layer be formed of an aqueous resin taking into consideration the prevention of environmental pollution and improvement of productivity and workability. Examples of preferred aqueous resins that can be used in the present invention include acrylic urethane resins, epoxy resins, polyurethane resins, polyisocyanate resins, polyester resins, acrylate resins, ethylene-vinyl acetate copolymers, polyamide resins, melamine resins, synthetic rubbers, and polyvinyl alcohol resins. Aqueous acrylic urethane resins are particularly preferred.

The primer layer is preferably formed using a two-solution type resin containing aqueous acrylic urethane (30 to 70 % by weight). 1 to 40 % by weight of an inorganic pigment is preferably added to the two-solution type resin to cover the background pattern of the base.

The primer layer serves to enhance the adhesion between the base layer and the transfer-printed layer, and is effective in enhancing the waterproofness of the finished product. Waterproofness is an important requirement for interior products.

The transfer-printed layer is formed using a general-purpose polyethylene terephthalate (PET) transfer paper.

According to the present invention, the surface coating layer consists of a surface primer layer, an under coating layer, an intermediate coating layer and a top coating layer. The primer layer is formed using an aqueous acrylic resin having a molecular weight of 100,000 to 200,000. An inorganic material selected from ceramics, glass chops, clays, silica and mixtures thereof is added to the under coating layer and the top coating layer to greatly improve the surface physical properties, such as scratch resistance, of the interior product, thereby preventing the surface of the interior product from damage, e.g., indentation, breakage and scratch, caused by a heavy or sharp object.

Finally, the interior product of the present invention is processed to have a tongue and groove (T & G) shape, a click system or a structure linked by a connector so that it can be joined to another interior product, which is the same one as the interior product of the present invention.

In accordance with another aspect of the present invention, there is provided a process for manufacturing an interior product, the process comprising: preparing a base layer; forming a primer layer on the base layer; performing transfer printing on the surface of the primer layer under heat and pressure to form a transfer-printed layer; forming a surface coating layer consisting of a surface primer layer, an under coating layer; an intermediate coating layer and a top coating layer on the transfer-printed layer; and cutting and shaping the resulting laminate. The formation of the primer layer on the base layer is preferably carried out by coating an aqueous resin to a predetermined thickness on the base layer, and passing the coated structure through an oven at 50 to 16O⁰C for 30 seconds to 5 minutes to dry and cure the coated structure.

Taking into consideration the prevention of the deformation and improvement of the productivity of the final product, it is preferred to perform the transfer printing under 0.4 to 1.0 MPa at 80 to 130°C for 5 seconds to 2 minutes.

Description of Drawings

The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of an interior product according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view of an interior product according to a second embodiment of the present invention;

FIG. 3 is a cross-sectional view of an interior product according to a third embodiment of the present invention;

FIG. 4 is a cross-sectional view of an interior product according to a fourth embodiment of the present invention;

FIG. 5 is a cross-sectional view of an interior product according to a fifth embodiment of the present invention; and

FIG. 6 is a top view of a finished product consisting of two interior products of the present invention, both of which have a tongue and groove (T & G) shape.

Best Mode

The present invention will now be described with reference to the accompanying drawings in greater detail. FIG. 1 is a cross-sectional view of an interior product according to a first embodiment of the present invention. As shown in FIG. 1, the interior product comprises a surface coating layer 10, a transfer-printed layer 20, a primer layer 30, and a base layer 40 laminated in this order from the top. The formation of the surface coating layer 10 is achieved by UV coating the surface of the transfer-printed layer 20. The surface coating layer generally consisjts of a surface primer layer, an under coating layer, an intermediate coating layer and a top coating layer, which are sequentially formed on the transfer- printed layer 20. To enhance the impact resistance and indentation resistance of the interior product surface, the surface primer layer is formed by UV curing a monomer and an oligomer having a relatively low molecular weight. This UV curing facilitates the coating of the monomer and oligomer and is preferably carried out for 10 seconds to 4 minutes. An inorganic material, such as a glass chop, may be added to the under coating layer to enhance the surface physical properties of the interior product. At this time, the inorganic material is preferably added in an amount of 0.1 to 10 % by weight.

A nano-sized inorganic material or silica may be added to the top coating layer to enhance the scratch resistance and wear resistance of the interior product surface. At this time, the nano-sized inorganic material or silica is preferably added in an amount of 0.1 to 10 % by weight.

The transfer-printed layer 20 is formed by a transfer printing technique to create the natural beauty of wood. Depending on the needs of consumers, patterns of all species of trees, including oak, birch, cherry, maple and walnut, may be faithfully and freely realized. For the transfer printing, general-purpose PET transfer printing papers may be used.

The primer layer 30 serves to cover the background fiber pattern of the base and enhance the adhesion between the base layer 40 and the transfer-printed layer 20. The primer layer is preferably formed of an aqueous resin. Examples of preferred aqueous resins that can be used in the present invention include acrylic urethane resins, epoxy resins, polyurethane resins, polyisocyanate resins, polyester resins, acrylate resins, ethylene-vmyl acetate copolymers, polyamide resins, heat-curable melamine resins, synthetic rubbers, and polyvinyl alcohol resins. Aqueous acrylic urethane resins are particularly preferred. As regulations restricting the use of volatile organic compounds (VOCs) are increasingly stringent and sick house syndrome is highlighted as a serious problem, general organic solvent type resins that are widely used in the art cannot be used to manufacture the interior product of the present invention. Instead, an aqueous resin is used in the present invention to reduce the amount of formaldehyde released to almost zero and prevent the occurrence of volatile organic solvents.

The base layer 40 may be formed of a plywood, a composite base, an inorganic board or a synthetic resin panel. Alternatively, the base layer 40 may be formed of a wood, a veneer, a particle board, a medium density fiberboard (MDF), a high density fiberboard (HDF), a high pressure laminate (HPL), a low pressure laminate (LPL), an oriented strand board (OSB), a flake board, a kenaf board, a corrugated cardboard or a paper.

It is preferable to use a plywood that has a specific weight of 0.4 to 0.8 g/cin³. The plywood is manufactured by laminating odd numbers (e.g., 3, 5, 7 etc.,) of veneers at right angels. Such plywood exhibits superior dimensional stability and high mechanical strength due to dispersion of defects (e.g., knots), compared to wood floorings. In addition, the plywood exhibits superior physical properties (e.g., water resistance, heat resistance, dimensional stability, thickness expansion rate), as compared to a fiberboard generally used as a base layer in laminated floorings. Based on these advantages, when the plywood is used as a base layer in interior products, it can realize great improvement in dimensional stability and moisture resistance of the products.

The veneer used herein is a veneer commonly used to manufacture plywood. The veneer for plywood is generally cut to have a thickness of 1.2 to

4.8 mm, but the thickness can be adjusted to a desired level depending on a specific structure.

The fiberboard has no constant orientation and is low-priced, compared to plywood. A medium density fiberboard (MDF) or high density fiberboard (HDF) may be generally used as the fiberboard. In particular, for flooring base- purpose, it is preferable to use a polished hard HDF having a specific weight of 0.85 g/cin³ or more. The HDF shows high hardness, superior water resistance, excellent dimensional stability, good mechanical properties, as compared to medium-density fiberboards (MDFs) and particle boards (PBs). Based on these advantages, when the high-density fiberboard is used as the base layer in interior products, it can realize great improvements in dimensional stability, impact strength and moisture resistance of the products.

The high-density fiberboard is low-priced and exhibits good wear resistance and impact resistance, compared to a water-resistant plywood. In addition, the high-density fiberboard is free of defects, such as knots, and exhibits uniform physical properties because fibers are orderly arranged in every direction. The HDF can be easily processed so as to have a very smooth and soft surface. Accordingly, the surface of the interior product using the HDF gives a feeling of smoothness and softness. The interior product of the present invention is processed to have a mechanical fixing system, such as a click construction structure or a linking structure for a connector so that it can be integrally joined to another interior product, which is the same one as the interior product of the present invention, in a vertical or horizontal direction.

FIG. 2 is a cross-sectional view of an interior product according to a second embodiment of the present invention. The interior product according to the second embodiment further comprises a paper layer 50 interposed between the primer layer 30 and the base layer 40, in addition to the interior product shown in FIG. 1.

The paper layer 50 acts as a reinforcing layer to improve the strength of the surface layer, and is formed of a paper, preferably a synthetic resin- impregnated paper.

FIG. 3 is a cross-sectional view of an interior product according to a third embodiment of the present invention. The interior product according to the second embodiment further comprises a synthetic-resin sheet layer 60 interposed between the primer layer 30 and the base layer 40, in addition to the interior product shown in FIG. 1.

The synthetic resin sheet layer 60 acts as a reinforcing layer to improve the strength of the surface layer, and is formed of a synthetic resin sheet.

Examples of synthetic resins that can be used for the paper layer 50 and the synthetic resin sheet layer 60 include poly vinyl chloride (PVC), poly ethylene (PE), poly propylene (PP), poly ethylene terephthalate (PET), poly ethylene terephthalate glycolmodified (PETG), high impact polystyrene (HIPS), acrylonitrile butadiene styrene (ABS), poly urethane (PU), styrene butadiene styrene (SBS) block copolymers, styrene ethylene butylene styrene (SEBS) block copolymers, syndiotactic poly styrene (SPS), and styrene ethylene propylene styrene (SEPS) block copolymers.

FIG. 4 is a cross-sectional view of an interior product according to a fourth embodiment of the present invention. As show in FIG. 4, the base layer of the fourth embodiment is a composite base consisting of a veneer 41, a fiberboard 42 and a veneer 41 laminated in this order from the bottom.

FIG. 5 is a cross-sectional view of an interior product according to a fifth embodiment of the present invention. According to the fifth embodiment, the base layer is a composite base consisting of a veneer 41 and a fiberboard 42 laminated in this order from the bottom, and a waterproof backing layer 70 is formed under the base layer. To enhance the water resistance of the interior product, the surface of the transfer-printed layer 20 is coated to form the surface coating layer 10, and the bottom surface of the high-density fiberboard layer is coated with a UV curable or heat curable surface-treating agent essentially composed of urethane acrylate or with at least one material selected from synthetic resins, e.g., polyolefm and polyester, wax, silicone-based water-repellent agents and silicone-based waterproofing agents to form the waterproof backing layer 70. The waterproof backing layer serves to prevent penetration of moisture into the fiberboard 42 to protect the interior product from decay and deformation.

The waterproof backing layer 70 is laminated under the base to enhance the water resistance of the interior product. The waterproof backing layer 70 is formed by coating the bottom surface of the fiberboard 42 with a UV curable or heat curable surface-treating agents, synthetic resins, waxes, silicone-based water- repellent agents, silicone-based waterproofing agents, etc.

Taking into consideration the ease of assembly, the interior product of the present invention is preferably processed into a general tongue and groove (T &

G) shape, but is not limited to this structure. For example, the interior product of the present invention may be processed to have a mechanical fixing system, such as a click construction structure or a structure linked by a connector so that it can be integrally joined to another interior product, which is the same one as the interior product of the present invention, in a vertical or horizontal direction.

The process for manufacturing an interior product according to the present invention comprises forming a primer layer 30 on a base layer 40 (a first step), forming a transfer-printed layer 20 on the primer layer 30 (a second step), performing surface coating of the transfer-printed layer 20 (a third step), and cutting and shaping the resulting structure (a fourth step). In the first step, the primer layer 30 is preferably dried at 50 to 160⁰C. An excessively high drying temperature causes severe deformation of the base layer. Meanwhile, too low a drying temperature may cause poor adhesion between the primer layer 20 and the base layer 40 due to insufficient drying of the prime* layer 30. Even when the two layers are adhered to each other, bad surface leveling may be caused at too low a drying temperature.

In the second step, transfer printing is preferably performed under a pressure of 0.4 to 1.0 MPa. The transfer-printed layer may be ruptured at too high a printing pressure. Meanwhile, poor printing may be caused at too low a printing pressure. The transfer printing is preferably performed for 5 seconds to 2 minutes. Too short a printing time may cause an occurrence of poor printing due to incomplete transfer of a printing ink. Meanwhile, too long a printing time may result in the rupture of the transfer-printed layer.

In the third step, a surface coating layer 10 is formed on the transfer- printed layer 20. The surface coating is performed by UV curing, which is a technique employed to manufacture general floorings. Specifically, a surface primer layer, an under coating layer, an intermediate coating layer and a top coating layer are sequentially formed on the transfer-printed layer 20, followed by UV curing. The surface coating layer 10 is formed of a UV curable or heat curable synthetic resin essentially composed of urethane acrylate. To achieve desired surface physical properties, such as superior resistance to indentation and impact, the surface coating layer 10 is formed of at least one resin selected from the group consisting of epoxy resins, polyamide resins, urea resins and acrylate resins. Particularly preferred is an epoxy resin.

To enhance the impact resistance and indentation resistance of the interior product surface, the surface primer layer is formed by curing an oil-phase or aqueous monomer and an oligomer having a relatively low molecular weight at 80 to '15O⁰C. This UV curing facilitates coating of the monomer and oligomer layer on the transfer-printed layer and is preferably carried out for 10 seconds to 4 minutes.

An inorganic material selected from ceramics, glass chops and mixtures thereof may be added to the under coating layer. The inorganic material is preferably added in an amount of 0.1 % to 10% by weight. At least one inorganic or nano-sized inorganic material selected from clays, ceramics and silica may be added to the top coating layer to improve the scratch resistance of the interior product surface. It is preferred to sufficiently disperse 0.1 to 10 parts by weight of the inorganic material in 100 parts by weight of a urethane acrylate resin and add the dispersion to the top coating layer so as not to affect the transparency of the top coating layer.

FIG. 6 is a top view of a finished product consisting of two interior products of the present invention, both of which have a tongue and groove (T & G) shape. As shown in FIG. 6, four sides of the finished product in both length and width directions are processed into two tongue sites 80 and two groove sites 90. Alternatively, the interior product of the present invention may be processed to have a mechanical fixing system, such as a click system or a system for a connector, so that it can be integrally joined to another interior product, which is the same one as the interior product of the present invention, in a vertical or horizontal direction. Hereinafter, preferred embodiments of the present invention will be explained. However, these embodiments are given for the purpose of illustration and are not intended to limit the present invention.

EXAMPLES Example 1

A primer layer 30 was formed on a plywood as a base layer 40 and a transfer-printed layer 20 was then formed thereon under heat and pressure. A surface coating layer 10 was formed on the transfer-printed layer 20, followed by cutting and processing into a tongue 80 and groove 90 shape to complete manufacture of the flooring including the transfer-printed layer and the plywood layer shown in FIG. 1.

Specifically, the primer layer 30 was formed using a two-solution type resin containing 50% by weight of aqueous acrylic urethane, and dried by passing the coated structure through an oven at 120⁰C for 2 minutes. The transfer- printed layer was formed using a general -purpose PET paper under heat (100⁰C) and pressure (0.7 MPa) for one minute. The base layer 40 was formed using a water-resistant plywood. The water-resistant plywood used herein had a density of 500 kg/m³ or more, a water content of 4.0 to 7.0% and a thickness of 7.5 to 8.0 mm. A surface primer layer, an under coating layer and an intermediate coating layer were sequentially formed on the transfer-printed layer 20. 5% by weight of a ceramic was added to the under coating layer. The resulting structure was cut to a width of 85 to 95 mm and a length of 850 to 950 mm using a tenoner, and the sides were processed to have a T & G shape. A top coating layer containing 5% by weight of a nano-sized inorganic material was formed on the intermediate coating layer, completing manufacture of an interior product.

Example 2

An interior product was manufactured in the same manner as in Example 1, except that the primer layer 30 was formed using a one-solution type resin containing 62% by weight of aqueous acrylate and drying was carried out in an oven at 120°C for one minute.

Example 3 A UV curable coating layer was coated under the bottom of a composite base layer consisting of a veneer 41 and a high-density fiberboard 42 to form a waterproof backing layer 70. A primer layer 30 was formed on the veneer 41 and a transfer-printed layer 20 was then formed thereon under heat and pressure. A surface coating layer 10 was formed on the transfer-printed layer 20, followed by cutting and processing into a tongue and groove shape to complete manufacture of the flooring shown in FIG. 5.

Specifically, the primer layer 30 was formed using a two-solution type resin containing 50% by weight of aqueous acrylic urethane, and dried by passing the coated structure through an oven at 12O⁰C for 2 minutes. The transfer- printed layer was formed using a general-purpose PET paper under heat (100°C) and pressure (0.7 MPa) for one minute. As the composite base layer 40, the veneer 41 used herein had a thickness of 1.2 mm and the high-density fiberboard 42 used herein had a density of 900 kg/m³ or more, a water content of 4.0 to 7.0% and a thickness of 7.5 to 8.0 mm. A surface primer layer, an under coating layer and an intermediate coating layer were sequentially formed on the transfer-printed layer 20. 5% by weight of a ceramic was added to the under coating layer. The resulting structure was cut to a width of 85 to 95 mm and a length of 850 to 950 mm using a tenoner, and the sides were processed to have a T & G shape. A top coating layer containing 5% by weight of a nano-sized inorganic material was formed on the intermediate coating layer, completing manufacture of an interior product.

Example 4

An interior product was manufactured in the same manner as in Example 3, except that the primer layer 30 was formed using a one-solution type resin containing 62% by weight of aqueous acrylate and drying was carried out in an oven at 120°C for one minute.

Comparative Example 1 A natural veneer was laminated on a water-resistant plywood as a base and surface-coated by UV curing to manufacture a plywood flooring for an under- floor heating system.

Comparative Example 2 A melamine resin was coated on a high-density fiberboard (HDF) as a base to manufacture a laminate flooring.

Test Example 1

The physical properties of the interior products manufactured in Examples 1 to 4 were compared with those of the floorings manufactured in Comparative Examples 1 and 2. The results are shown in Table 1. TABLE 1

The indentation resistance of the interior products was evaluated by dropping a flat-head screwdriver weighing 11 Og onto the surfaces (inclined at an angle of 45 degrees relative to the horizontal plane) of the interior products and measuring a height at which surface indentation was observed. As is apparent from the data shown in Table 1, the surfaces of the laminate flooring (Comparative Example 2) and the plywood flooring for an under-floor heating system (Comparative Example 1) were indented when the flat-head screwdriver was dropped from a height of 10 cm, while the surfaces of the interior products (Examples 1 and 2, and Examples 3 and 4) were indented when the flat-head screwdriver was dropped from a height of 20 cm and 25 cm, respectively. The breakage resistance of the interior products was evaluated by dropping an iron ball having a diameter of 3 cm and a weight of 228g onto the surfaces of the interior products and measuring a height at which surface breakage was observed. As can be seen from the data shown in Table 1, the surfaces of the laminate flooring (Comparative Example 2) and the plywood flooring for an under-^'floor heating system (Comparative Example 1) were broken when the iron ball was dropped from heights of 35 cm and 20 cm, respectively, while the surfaces of the interior products according to the present invention (Examples 1 to 4) were broken when the iron ball was dropped from a height of 50 cm.

The dimensional stability of the interior products was evaluated by allowing the interior products to stand in an oven at 80°C and a water bath at room temperature for 24 hours and measuring dimensional variations in length (L) and width (W). According to the test results of Table 1, the dimensional stability of the floorings according to the present invention was comparable to that of the plywood flooring for an under-floor heating system, but was much excellent when compared to that of the laminate flooring.

The scratch resistance of the interior products was evaluated by measuring the degree of surface scratching under a load (N) using a Clemens-type scratch hardness tester in accordance with the procedure described in Paragraph 3.15 of the standard method KS M3332. From the test results of Table 1, it could be confirmed that the scratch resistance (5.0 N) of the floorings according to the present invention was superior to that (3.0 N) of the plywood flooring for an under-floor heating system and that (4.0 N) of the laminate flooring.

The thickness expansion rate of the floorings after water absorption was evaluated by dipping the floorings in water at room temperature for 24 hours (U type, Paragraph 6.9 of KS F32009) and water at 70°C for 2 hours (M type), and measuring the variation in the thickness of the floorings. As is evident from the test results of Table 1, the thickness expansion rates of the floorings according to the present invention were lower than thickness expansion rates of the plywood flooring and the laminate flooring.

Test Example 2

The physical properties of the interior products manufactured in Examples 1 and 2 were compared with those of the interior products manufactured in Comparative Examples 1 and 2. The results are shown in Table 2.

TABLE 2

The warp stability of the interior products was evaluated by allowing the samples to stand in an oven at 80 ± 2°C for 24 hours and measuring the number of curls and domes. As a result, the warp stability in the width direction of the floorings according to the present invention was excellent when compared to the laminate flooring and the plywood flooring for an under-floor heating system. In addition, the warp stability (0.89 mm and 0.91 mm) in the lengthwise direction of the floorings (Examples 1 and 2) according to the present invention was slightly poor when compared to that (0.96 mm) of the conventional laminate flooring (Comparative Example 2), but was much better than that (5.77 mm) of the plywood flooring (Comparative Example 1) for an under-floor heating system.

From these experimental results, it could be presumed that the interior products of the present invention showed superior surface physical properties, e.g., superior resistance to indentation and breakage caused by a heavy or sharp object, as compared to the plywood flooring for an under-floor heating system and the laminate flooring, and that the interior products of the present invention exhibit superior dimensional stability owing to the plywood used as a base, as compared to the laminate flooring. Industrial Applicability

As apparent from the above description, according to the interior product of the present invention, an aqueous resin (e.g., aqueous acrylic urethane) is coated on a base layer to form a primer layer and transfer printing is performed on the surface of the primer layer to form a printed layer so that the background fiber patten* of the base is covered, the adhesion of the base layer to the printed layer is enhanced, and a variety of elaborate surface images are expressed. In addition, according to the interior product of the present invention, the addition of an organic material selected from glass chops, ceramics, clays, silica and mixtures thereof to a surface coating layer formed on the printed layer leads to considerable improvement of the surface physical properties, such as indentation resistance and scratch resistance, of the interior product. In particular, the transfer-printed layer formed by directly performing transfer printing on the base layer enables faithful realization of the natural beauty of wood, reduces color difference between final products, eliminates surface defects such as cracks, dead knots or knife traces, and minimizes an increase in manufacturing cost, which arises from the use of expensive materials for surface layers>Jof conventional interior products.

In addition, the interior product of the present invention realizes excellent natural feeling of the wood, thus ensuring a desired color and pattern, as compared to low-pressure melamine (LPM)-impregnated papers which are generally used as surface materials in laminated floorings. According to the present invention, the use of a composite base for the interior product enables the interior product to exhibit superior physical properties (e.g., dimensional stability and thickness expansion rate), as compared to high density fϊberboards (HDFs).

The demands of construction companies, valued customers of floorings, have brought about a big issue of color matching. According to the present invention, direct transfer printing on the base layer is ensured, thus manufacturing diverse designs of interior products that are capable of satisfying such a demand through realization of a variety of colors and patterns of interior products. In addition, the application of the composite base to the interior product serves to solve the problem of water resistance (e.g., dimensional stability or thickness expansion rate), which is one of major drawbacks of HDFs, thus enabling differentiation from other interior products.

Claims

1. An interior product comprising a base layer, a primer layer and a printed layer laminated in this order from the bottom.

2. The interior product according to claim 1, wherein the base layer is a plywood.

3. The interior product according to claim 1, wherein the base layer has a multilayer structure in which two or more wood materials are laminated.

4. The interior product according to claim 1, wherein the base layer is an inorganic board or a synthetic-resin panel.

5. The interior product according to claim 1, wherein the base layer is composed of at least one selected from a wood, a veneer, a particle board, a medium density fiberboard (MDF), a high density fiberboard (HDF), a high pressure laminate (HPL), a low pressure laminate (LPL), an oriented strand board (OSB), a flake board, a kenaf board, a corrugated cardboard and a paper.

6. The interior product according to claim 1, further comprising a reinforcing layer interposed between the primer layer and the base layer.

7. The interior product according to claim 6, wherein the reinforcing layer is composed of a paper or a synthetic-resin sheet.

8. The interior product according to claim 3, wherein the wood materials are composed of at least two materials selected from a wood, a veneer, a particle board, a medium density fiberboard (MDF), a high density fiberboard (HDF), a high pressure laminate (HPL), a low pressure laminate (LPL), an oriented strand board (OSB), a flake board, a kenaf board, a corrugated cardboard and a paper.

9. The interior product according to claim 3, wherein the multilayer structure includes a veneer, a fiberboard and a veneer laminated in this order from the bottom.

10. The interior product according to claim 3, wherein the multiplayer structure includes a fiberboard and a veneer laminated in this order from the bottom.

11. The interior product according to claim 1, further comprising a backing layer arranged under the base layer and a surface coating layer arranged on the printed layer.

12. The interior product according to claim 11, wherein the backing layer is composed of at least one selected from a paper, a metal foil, a UV curable surface-treating agent, a heat curable surface-treating agent, a synthetic resin, a wax, a silicone-based water-repellent agent and a silicone-based waterproofing agent.

13. The interior product according to claim 1, wherein the primer layer is composed of an aqueous resin.

14. The interior product according to claim 13, wherein the aqueous resin is selected from acrylic urethane resins, epoxy resins, polyurethane resins, polyisocyanate resins, polyester resins, acrylate resins, ethylene-vinyl acetate copolymers, polyamide resins, melamine resins, synthetic rubbers, polyvinyl alcohol resins, and mixtures thereof.

15. The interior product according to claim 14, wherein the primer layer is composed of a two-solution type resin containing an aqueous acrylic urethane.

16. The interior product according to claim 1, wherein the primer layer contains 1 to 40 % by weight of a pigment.

17. The interior product according to claim 1, wherein the printed layer is a transfer-printed layer formed using a general-purpose polyethylene terephthalate (PET) transfer paper.

18. The interior product according to claim 11, wherein the surface coating layer comprises an under coating layer, an intermediate coating layer and a top coating layer laminated in this order from the bottom, and each of the under coating layer and the top coating layer includes an inorganic material selected

5 from ceramics, glass chops, clays, silica, and mixtures thereof.

19. The interior product according to claim 1, wherein the interior product has a tongue and groove (T & G) shape, a click system, or a structure linked by a connector.

L O

20. A process for manufacturing an interior product, comprising the steps of: preparing a base layer; forming a primer layer on the base layer;

15 performing transfer printing on the primer layer to form a transfer-printed layer; forming a surface coating layer on the transfer-printed layer; and cutting and shaping the resulting laminate. 0 21. The process according to claim 20, wherein the primer layer is formed by coating an aqueous resin on the base layer, and drying the coated resin at 80 to 160⁰C for 30 seconds to 5 minutes.

22. The process according to claim 20, wherein the transfer printing is 5 performed under 0.4 to 1.0 MPa at 80 to 13O⁰C for 5 seconds to 2 minutes.