CN118159710A

CN118159710A - Floor material and method for manufacturing floor material

Info

Publication number: CN118159710A
Application number: CN202280071894.6A
Authority: CN
Inventors: 角亘; 河西宏树; 加藤丈晴
Original assignee: Dai Nippon Printing Co Ltd; Kaneka Corp
Current assignee: Dai Nippon Printing Co Ltd; Kaneka Corp
Priority date: 2021-11-19
Filing date: 2022-11-15
Publication date: 2024-06-07
Also published as: JPWO2023090319A1; WO2023090319A1

Abstract

The purpose is to realize a floor material with excellent level difference of tongue groove and ejection inhibition effect and joggability of the tongue groove. The floor material (10) of the present invention is characterized in that the linear expansion coefficients of the foamed resin layer (1) and the non-foamed resin layer (2) and the difference between the linear expansion coefficients of the two layers are defined within a specific range, the tensile elastic modulus of the non-foamed resin layer (2) and the difference between the tensile elastic modulus of the foamed resin layer (1) and the non-foamed resin layer (2) are defined within a specific range, and the tongue-and-groove portion of the floor material (10) is composed of the foamed resin layer (1) and the non-foamed resin layer (2).

Description

Floor material and method for manufacturing floor material

Technical Field

The present invention relates to a flooring material and a method for manufacturing the flooring material.

Background

Conventionally, a floor material is generally used in which a surface decorative material such as a decorative sheet or a decorative paper is bonded to a wood base material such as a single body of plywood or a wood fiber board or a composite base material.

These flooring materials have poor water resistance and tend to mold or warp. Therefore, there is a problem in that the flooring material is stably used all the time in summer and winter. For these problems, applications of the flooring materials disclosed in patent documents 1 to 3 have been studied as a flooring material having a resin foam layer excellent in water resistance and heat insulation formed using a resin material that is a non-wood material.

Patent documents 1 and 2 disclose a decorative material including a foamed resin layer and a non-foamed resin layer. For the decorative material disclosed in patent document 1, (a) the compressive elastic modulus of the foamed resin layer is 15MPa or more, the linear expansion coefficients of the non-foamed resin layer and the foamed resin layer are 8×10 ^-5/°c or less, and (b) the difference between the linear expansion coefficients of the non-foamed resin layer and the foamed resin layer is 3×10 ^-5/°c or less.

The decorative material disclosed in patent document 2 has the following structure. When the tongue portion of one decorative material and the groove portion of the other decorative material are mutually embedded, the foaming resin layer of one decorative material and the foaming resin layer of the other decorative material are not mutually contacted.

Patent document 3 discloses a flooring material in which tongue-and-groove portions are formed in both a foamed resin layer and a non-foamed resin layer.

Prior art literature

Patent literature

Patent document 1: international publication No. 2017/217518

Patent document 2: international publication No. 2017/217519

Patent document 3: utility model registration number 3178630

Disclosure of Invention

Problems to be solved by the invention

However, the floor materials disclosed in patent documents 1 to 3 have room for improvement in terms of construction quality, particularly, suppression of level differences in tongue groove portions, fitting property of tongue groove portions, and suppression of fitting protrusion (upper protrusion of fitting protrusion) of tongue groove portions due to dimensional changes accompanying temperature changes.

An object of one embodiment of the present invention is to provide a floor material and a method for producing a floor material, which are excellent in the level difference and the jack-up suppressing effect of tongue groove portions and in the fitting property of tongue groove portions.

Solution for solving the problem

The present inventors have conducted intensive studies on a flooring material comprising a non-foamed resin layer and a foamed resin layer, and as a result, have found that (i) the difference between the linear expansion coefficients of the foamed resin layer and the non-foamed resin layer and the linear expansion coefficient of the two layers are defined within a specific numerical range, (ii) the difference between the tensile elastic modulus of the non-foamed resin layer and the tensile elastic modulus of the non-foamed resin layer is defined within a specific numerical range, and (iii) the tongue groove portion of the flooring material is composed of the non-foamed resin layer and the foamed resin layer, whereby the flooring material having excellent level difference and jack-up suppressing effect of the tongue groove portion and excellent fitting property of the tongue groove portion can be achieved, and have completed the present application. That is, in order to solve the above-described problems, one embodiment of the present application is as follows.

A floor material according to an aspect of the present invention includes: a flooring material body in which a decorative layer, a non-foamed resin layer, and a foamed resin layer are laminated in this order, wherein the linear expansion coefficients of the non-foamed resin layer and the foamed resin layer are each 8×10 ^-5/DEG C or less, the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer from the linear expansion coefficient of the foamed resin layer is greater than 3×10 ^-5/DEG C and 6×10 ^-5/DEG C or less, the non-foamed resin layer contains an inorganic compound, and the tensile elastic modulus is 4000MPa to 9000MPa, the difference between the tensile elastic moduli of the non-foamed resin layer and the foamed resin layer is 3000MPa or more, and the flooring material includes a tongue portion formed at an end portion of the flooring material body or a groove portion capable of being fitted with the tongue portion, and the tongue portion is composed of the non-foamed resin layer and the foamed resin layer.

A method for manufacturing a floor material according to an embodiment of the present invention includes:

A preparation step of preparing a non-foaming resin layer and a foaming resin layer having the following characteristics,

The linear expansion coefficients of the non-foamed resin layer and the foamed resin layer are each 8X 10 ^-5/DEG C or less, and the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer from the linear expansion coefficient of the foamed resin layer is greater than 3X 10 ^-5/DEG C and 6X 10 ^-5/DEG C or less,

The non-foaming resin layer contains an inorganic compound and has a tensile elastic modulus of 4000MPa to 9000MPa,

The difference between the tensile elastic modulus of the non-foamed resin layer and the tensile elastic modulus of the foamed resin layer is 3000MPa or more;

a lamination step of laminating a decorative layer, the non-foamed resin layer, and the foamed resin layer in this order to form a flooring material body; and

And a tongue groove forming step of forming a tongue or a groove capable of fitting with the tongue so as to be constituted by the non-foamed resin layer and the foamed resin layer at an end portion of the flooring material body.

ADVANTAGEOUS EFFECTS OF INVENTION

According to one aspect of the present invention, a floor material having excellent level difference and jack-up suppressing effect in tongue groove portions and excellent fitting property in tongue groove portions can be realized.

Drawings

Fig. 1 is a cross-sectional view showing a schematic structure of a flooring material according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a structure of a modified example of the flooring material according to the embodiment of the present invention.

Fig. 3 is a sectional view showing the structure of a tongue-and-groove portion of the flooring material according to the embodiment of the present invention.

Fig. 4 is a cross-sectional view showing a structure of a tongue-and-groove portion of a flooring material according to an embodiment of the present invention, which has been subjected to a snap-in process.

In fig. 5, 501 to 503 are diagrams for explaining a method of evaluating the quality of the construction of the flooring materials of examples and comparative examples.

Detailed Description

An embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to the technical features described below, and various modifications are possible within the scope of the claims. Further, embodiments or examples obtained by combining the means of the techniques disclosed in the different embodiments or examples are also included in the technical scope of the present invention. Further, by combining the means of the techniques disclosed in the respective embodiments, new features of the techniques can be formed. All of the academic documents and patent documents described in the present specification are incorporated by reference into the present specification. In the present specification, "a to B" representing a numerical range means "a or more (including a and more than a) and B or less (including B and less than B)", unless otherwise specified. Further, the drawings are shown in an easily understood manner when they are referred to in conjunction with the following description, and are not necessarily drawn to scale with a fixed ratio.

An embodiment of the present invention will be described in detail below. Fig. 1 is a cross-sectional view showing a schematic structure of a flooring material 10 according to the present embodiment.

As shown in fig. 1, the flooring material 10 of the present embodiment has a structure including a main body B (flooring material main body) in which a foamed resin layer 1, a non-foamed resin layer 2, and a decorative layer 3 are laminated in this order. Although not shown in fig. 1, the foamed resin layer 1 is bonded to the non-foamed resin layer 2 via an adhesive layer. In the present application, the foamed resin layer 1 side is set to the lower side with respect to the non-foamed resin layer 2, and the decorative layer 3 side is set to the upper side with respect to the non-foamed resin layer 2.

The floor material 10 has the following technical features (a) to (c). (a) The linear expansion coefficients of the non-foamed resin layer 2 and the foamed resin layer 1 are each 8×10 ^-5/DEG C or less, and the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer 2 from the linear expansion coefficient of the foamed resin layer 1 is greater than 3×10 ^-5/DEG C and 6×10 ^-5/DEG C or less. (b) The non-foaming resin layer 2 contains an inorganic compound, and has a tensile elastic modulus of 4000MPa to 9000MPa, and the difference between the tensile elastic moduli of the non-foaming resin layer 2 and the foaming resin layer 1 is 3000MPa or more. (c) The floor material 10 includes a tongue portion formed at an end of the main body B of the floor material 10 or a groove portion capable of being fitted to the tongue portion, and the tongue portion and the groove portion are constituted by the non-foamed resin layer 2 and the foamed resin layer 1.

By providing the floor material 10 with the above-described technical features (a) to (c), it is possible to realize a floor material 10 excellent in the level difference and the jack-up suppressing effect of the tongue groove portion and the fitting property of the tongue groove portion.

First, in the technical feature (a), if the linear expansion coefficients of the foamed resin layer 1 and the non-foamed resin layer 2 exceed 8×10 ^-5/°c, the expansion and contraction of the floor material 10 with respect to temperature change tend to increase. When the flooring material 10 is elongated, there are drawbacks such as warpage of the flooring material 10 and lifting of the fitting portion when 2 or more flooring materials 10 are fitted. On the other hand, when the floor material 10 is reduced in size, when 2 or more floor materials 10 are fitted together via the tongue groove portions, a problem occurs in the appearance of the floor material 10. As this problem, for example, a gap is generated in the fitting portion of the flooring materials 10.

Further, according to the above feature (a), the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer 2 from the linear expansion coefficient of the foamed resin layer 1 is greater than 3×10 ^-5/°c and is 6×10 ^-5/°c or less. If this value exceeds 6×10 ^-5/°c, the difference between the expansion and contraction degrees of the foamed resin layer 1 and the non-foamed resin layer 2 with respect to the temperature change increases, and there is a possibility that the floor material 10 may warp. However, according to the above technical features of the flooring material 10), that is, the non-foamed resin layer 2 contains an inorganic compound, and has a tensile elastic modulus of 4000MPa to 9000MPa, and the difference between the tensile elastic moduli of the non-foamed resin layer 2 and the foamed resin layer 1 is 3000MPa or more. In this way, the tensile elastic modulus of the non-foamed resin layer 2 is sufficiently large relative to the tensile elastic modulus of the foamed resin layer 1, and the difference between the tensile elastic moduli of the non-foamed resin layer 2 and the foamed resin layer 1 is 3000MPa or more, so that expansion and contraction of the foamed resin layer 1 due to a temperature change can be suppressed by the non-foamed resin layer 2.

The tensile elastic modulus of the non-foaming resin layer 2 is more preferably 4500MPa to 8500MPa, still more preferably 5000MPa to 8000MPa. The difference in tensile elastic modulus between the non-foamed resin layer 2 and the foamed resin layer 1 is more preferably 4000MPa or more, and still more preferably 5000MPa or more. The upper limit of the difference between the tensile elastic moduli is not particularly limited, but is preferably 8000MPa or less.

If the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer 2 from the linear expansion coefficient of the foamed resin layer 1 exceeds 6×10 ^-5/°c, the expansion and contraction of the foamed resin layer 1 due to a temperature change tend to be difficult to be suppressed by the non-foamed resin layer 2 even if the tensile elastic modulus of the non-foamed resin layer 2 is sufficiently large with respect to the tensile elastic modulus of the foamed resin layer 1. Therefore, the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer 2 from the linear expansion coefficient of the foamed resin layer 1 is greater than 3×10 ^-5/°c and is 6×10 ^-5/°c or less.

The value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer 2 from the linear expansion coefficient of the foamed resin layer 1 is more preferably 3.5X10 ^-5/℃～5.0×10^-5/DEG C or less, still more preferably 3.8X10/^-5/℃～4.3×10^-5/DEG C or less.

Here, the linear expansion coefficients of the foamed resin layer 1 and the non-foamed resin layer 2 are values measured by the following method. First, a rectangular parallelepiped test piece having a longitudinal direction of 100mm and a transverse direction of 300mm was cut out for each layer member (each layer of the foamed resin layer 1 and the non-foamed resin layer 2) of the flooring material 10. Next, for each of the cut test pieces, dimensional changes in the lateral direction were measured when the temperature of the test piece was stabilized at 0 ℃ and 40 ℃ using a constant temperature bath, and the dimensional change amount per unit temperature was calculated from the dimensional changes. 3 test pieces cut from any 3 of the floor materials 10 were prepared, the dimensional change amount per unit temperature was measured for each test piece in the above-described manner, and the value obtained by arithmetic averaging them was used as the linear expansion coefficient. In the present embodiment, the dimensional change in the thickness direction of each layer member is extremely small compared with the dimensional changes in the longitudinal direction and the transverse direction, and therefore, can be ignored.

The linear expansion coefficient of the foamed resin layer 1 is preferably 8.0X10 ^-5/DEG C or less, more preferably 7.5X10 ^-5/DEG C or less, and still more preferably 7.0X10 ^-5/DEG C or less. The lower limit is not particularly limited, but is preferably 5.0X10 ^-5/DEG C or more, for example. The linear expansion coefficient of the non-foamed resin layer 2 is preferably 3.5X10 ^-5/DEG C or less, more preferably 3.3X10 ^-5/DEG C or less, and still more preferably 3.0X10 ^-5/DEG C or less. The lower limit is not particularly limited, but is preferably 2.0X10 ^-5/DEG C or more, for example.

As described above, according to the floor material 10, the expansion and contraction of the foamed resin layer 1 due to the temperature change can be suppressed by the above-described technical features (a) and (b), and therefore, the floor material 10 excellent in the level difference of the tongue groove portion and the suppression effect of the jack-up can be realized. On the other hand, as in the above-described feature (b), since the non-foamed resin layer 2 contains an inorganic compound and the tensile elastic modulus of the non-foamed resin layer 2 is sufficiently large relative to the tensile elastic modulus of the foamed resin layer 1, if the tongue-and-groove portion is formed only by the non-foamed resin layer 2, cracks and chipping may occur, and the chimerism tends to be deteriorated.

Therefore, according to the flooring material 10, as in the above-described technical feature (c), the tongue and groove portions formed in the tongue-and-groove portion of the end portion of the main body B of the flooring material 10 are constituted by the non-foamed resin layer 2 and the foamed resin layer 1. Therefore, the floor material 10 having sufficient fitting strength in the tongue groove portion and excellent fitting property in the tongue groove portion can be obtained.

As described above, according to the flooring material 10 of the present embodiment, by providing the above-described technical features (a) to (c), the flooring material 10 having excellent level difference and jack-up suppressing effects in the tongue groove portion and excellent fitting properties in the tongue groove portion can be realized.

Fig. 2 is a cross-sectional view showing a structure of a modified example of the flooring material 10 according to the present embodiment. As shown in fig. 2, the floor material 10A as a modification example has a structure of the decorative layer 3A different from that of the floor material 10 shown in fig. 1. The decorative layer 3A includes a base resin layer 31, a pattern layer 32, an adhesive layer 33 for a decorative layer, a transparent resin layer 34, and a surface protective layer 35. The base resin layer 31 is laminated on the non-foaming resin layer 2. The decorative layer 3A has a structure in which a base resin layer 31, a pattern layer 32, an adhesive layer 33 for decorative layers, a transparent resin layer 34, and a surface protective layer 35 are laminated from the lower side toward the upper side. Even with the flooring material 10A shown in fig. 2, the flooring material 10A having excellent level difference and jack-up suppressing effect in the tongue groove portion and excellent fitting property in the tongue groove portion can be realized.

The structures of the layers and tongue-and-groove portions of the flooring material 10 shown in fig. 1 and the flooring material 10A shown in fig. 2 are described in detail below.

(Foaming resin layer 1)

The foamed resin layer 1 is a layer that imparts mainly heat insulation, load resistance, and impact resistance to the flooring material 10. The foamed resin layer 1 is formed by foaming a foamed resin composition.

The expansion ratio of the foamed resin layer 1 is not particularly limited, but is preferably 5 to 20 times. When the expansion ratio is outside the above range, excellent heat insulation, load resistance and impact resistance cannot be obtained. The foaming ratio of the foamed resin layer 1 is more preferably 5 to 15 times, and still more preferably 5 to 12 times, from the viewpoint of obtaining excellent heat insulation and load resistance.

The modulus of elasticity in compression of the foamed resin layer 1 is not particularly limited, but is preferably 15MPa or more. If the compressive elastic modulus of the foamed resin layer 1 is less than 15MPa, excellent load resistance and impact resistance cannot be obtained. The compression elastic modulus of the foamed resin layer 1 is preferably 15 to 100MPa, more preferably 20 to 50MPa, from the viewpoint of obtaining excellent load resistance and impact resistance.

Here, the compression elastic modulus is a modulus obtained by molding a foam according to JIS a9511:1999 "foam insulating material" are samples prepared and measured by the method described in "foam insulating material". Specifically, a test piece having a rectangular parallelepiped shape of 100mm in longitudinal direction, 100mm in transverse direction, and 30mm in thickness was cut out from the foamed resin layer 1, and the compression modulus was measured at a compression rate of 10 mm/min using a TENSILON tester. 5 test pieces were prepared, and the compressive elastic modulus was measured for each test piece in the above-described manner, and the value obtained by arithmetically averaging them was used as the compressive elastic modulus.

On the other hand, the floor material 10 is not particularly limited as long as the difference between the tensile elastic modulus of the foamed resin layer 1 and the tensile elastic modulus of the non-foamed resin layer 2 is 3000MPa or more. The tensile elastic modulus of the foamed resin layer 1 is preferably 30 to 300MPa. If the tensile elastic modulus of the foamed resin layer 1 is less than 30MPa, the foamed resin layer 1 tends to become soft. Therefore, when other layers such as the non-foamed resin layer 2 are laminated on the foamed resin layer 1, the foamed resin layer 1 is significantly stretched when tension is applied to the foamed resin layer 1. As a result, the foamed resin layer 1 may not exhibit dimensional accuracy such as length and width. If the tensile elastic modulus of the foamed resin layer 1 exceeds 300MPa, the foamed resin layer 1 tends to become hard and brittle. Therefore, when other layers such as the non-foamed resin layer 2 are laminated and processed on the foamed resin layer 1, the foamed resin layer 1 may be cracked.

The tensile elastic modulus of the foamed resin layer 1 was obtained by preparing the foamed resin layer 1 punched into a dumbbell-shaped test piece described in JIS K6732 (1996), measuring the tensile stress-strain curve at a tensile speed of 50 mm/min and a distance between chucks of 80mm using a tensile compression tester at a temperature of 20 ℃, and calculating the tensile stress-strain curve from the first straight line portion of the tensile stress-strain curve by the following formula.

E＝Δρ/Δε

E: modulus of elasticity in tension

Δρ: stress difference caused by original average sectional area between 2 points on straight line

Δε: deformation difference between the same 2 points.

Further, from the viewpoint of imparting sufficient heat insulating properties, the lower the thermal conductivity of the foamed resin layer 1, the more preferably 0.020W/m·k to 0.042W/m·k, more preferably 0.023W/m·k to 0.038W/m·k, and still more preferably 0.025W/m·k to 0.035W/m·k. The foamed resin layer 1 having a thermal conductivity of less than 0.020W/mK is difficult to realize at low cost and is not practical from the viewpoint of economy.

The foaming method of the foaming resin composition is not particularly limited, and any known method may be used, but foaming by the bead method is preferable from the viewpoint of obtaining a uniform foaming resin layer 1. The bead method is a method using foamed resin particles (pre-foamed particles) as a raw material. In the bead method, the foamed resin particles are filled into the cavity of a mold, and the foamed resin particles are integrated with each other by heat fusion while the filled foamed resin particles are secondarily foamed with steam, thereby obtaining the foamed resin layer 1.

The resin used in the foamed resin particles is not particularly limited, and thermoplastic resins are preferably used. The thermoplastic resin is preferably a polyolefin resin such as a polyethylene resin, a polypropylene resin, a polystyrene resin, an ethylene-vinyl acetate copolymer resin (EVA), or an ethylene- (meth) acrylic resin; polyvinyl resins such as acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene copolymer, polyvinyl chloride resin, polyvinyl acetate resin, and polyvinyl alcohol resin; polyester resins such as polyethylene terephthalate resins (PET resins); thermoplastic resins such as nylon, polyacetal resin, acrylic resin, polycarbonate resin, polyurethane resin, and the like, or a mixture thereof. Among them, the resin used in the foamed resin particles is preferably a polyolefin resin, particularly preferably a polystyrene resin, in view of the strength of the resin itself.

In a particularly preferred embodiment of the foamed resin layer 1, the foamed resin layer 1 is a polystyrene resin layer and has a foaming ratio of 5 to 20 times.

The styrene monomer forming the polystyrene resin is not particularly limited, and any of known styrene monomers can be used. Examples thereof include styrene, α -methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, isopropylstyrene, dimethylstyrene, bromostyrene and the like. These styrenic monomers may be a mixture of one or more. The preferred styrenic monomer is styrene.

The foamed resin particles are generally formed by (1) absorbing and polymerizing monomers such as styrene monomers and, if necessary, plasticizers in seed particles formed from a resin forming the foamed resin particles, thereby forming resin particles; (2) And a step of impregnating the resin particles with a foaming agent simultaneously with or after the polymerization, and then foaming the resin particles. The expanded resin beads may be obtained by a method in which a monomer such as a styrene monomer is suspension-polymerized in an aqueous medium to obtain particles, and the particles are impregnated with a foaming agent.

As the foaming agent, inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite are preferably used as the chemical foaming agent; nitroso compounds such as N, N ' -dimethyl-N, N ' -dinitroso terephthalamide and N, N ' -dinitroso pentamethylene tetramine; azo compounds such as azodicarbonamide, azodiisobutyronitrile, azocyclohexanecarbonitrile and azodiaminobenzene; sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide and toluenesulfonyl hydrazide; and azide compounds such as calcium azide, 4' -diphenyldisulfonyl azide and p-toluenesulfonyl azide. Further, as the blowing agent, aliphatic hydrocarbons such as propane, n-butane, isopentane, n-pentane, neopentane, and the like are preferably used as the physical blowing agent. Further, as the foaming agent, in addition to the above physical foaming agent, a volatile foaming agent such as fluorinated hydrocarbon having zero ozone destruction coefficient such as difluoroethane and tetrafluoroethane is preferably used. These foaming agents may be used singly or in combination of plural kinds.

The amount of the foaming agent to be added is preferably 0.5 to 15 parts by mass, more preferably 1 to 10 parts by mass, based on 100 parts by mass of the resin, as long as the amount is appropriately determined according to the desired expansion ratio and compression elastic modulus.

The plasticizer is preferably a fatty acid ester compound such as propylene glycol fatty acid ester, glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, or the like; phthalate compounds such as dibutyl phthalate (DBP), dioctyl phthalate (DOP), and diisononyl phthalate (DINP); adipate compounds such as diisobutyl adipate and dioctyl adipate; sebacate compounds such as dibutyl sebacate and di-2-ethylhexyl sebacate; glycerol fatty acid ester compounds such as glycerol tristearate and glycerol trioctanoate; natural oils such as liquid paraffin, coconut oil, palm oil, and rapeseed oil.

The plasticizer may be added when the monomer is polymerized or may be added when the foaming agent is impregnated. The amount of the plasticizer to be added is preferably 0.2 parts by mass or more and less than 3 parts by mass, more preferably 0.4 parts by mass or more and less than 1.6 parts by mass, based on 100 parts by mass of the resin, as determined appropriately according to the desired expansion ratio and compression elastic modulus. If the amount of plasticizer is 0.2 parts by mass or more, the secondary transition temperature is lowered, and thus, the pre-foaming and molding at low temperature are facilitated, and if it is less than 3 parts by mass, the foam is less likely to shrink, and a good appearance is obtained.

The foamed resin particles may contain additives such as flame retardants, flame retardant aids, lubricants, adhesion inhibitors, fusion promoters, antistatic agents, spreaders, bubble control agents, crosslinking agents, fillers, and colorants within a range that does not impair physical properties.

In the bead method, for example, the foamed resin particles are filled into a cavity of a mold, and the filled foamed resin particles are secondarily foamed by heating for 10 to 40 seconds using a heat medium such as steam at 100 to 150 ℃, preferably 100 to 120 ℃, and the foamed resin particles are integrated with each other by heat fusion, whereby the foamed resin layer 1 can be obtained. In this case, the average particle diameter of the foamed resin particles to be used is preferably 0.2 to 4mm, more preferably 0.5 to 2mm.

The foaming resin layer 1 is not limited to the bead method described above, and can be produced by the following method, for example. That is, first, a resin composition for forming a foamed resin layer containing a resin for a foamed resin layer, a foaming agent, a plasticizer, an inorganic filler, and other additives as needed is used, and an unfoamed resin layer is formed by a film-forming method such as an extrusion film-forming method or a calendaring film-forming method using a rectangular die. Then, the unfoamed resin layer is foamed at about 220 to 250 ℃ using a heating foaming furnace, whereby the foamed resin layer 1 can also be obtained.

Further, as the foamed resin layer 1, a commercially available heat insulating plate may be used as long as the conditions of the above-described technical features (a) and (b) are satisfied. Examples of the heat insulating sheet include polystyrene foam heat insulating sheets by bead method and polystyrene foam heat insulating sheets by extrusion method.

The thickness of the foamed resin layer 1 is preferably 3 to 15mm, more preferably 5 to 15mm, and still more preferably 5 to 12mm. When the thickness of the foamed resin layer 1 is within the above range, the flooring material 10 excellent in heat insulation, load resistance and impact resistance can be obtained.

The thickness of the foamed resin layer 1 is preferably thicker than the non-foamed resin layer 2 described later. Thus, the flooring material 10 excellent in heat insulation, load resistance and impact resistance can be obtained.

(Non-foaming resin layer 2)

The non-foamed resin layer 2 is a layer that imparts mainly shape stability, water resistance, moisture resistance, impact resistance, and scratch resistance to the flooring material 10. The tensile elastic modulus of the non-foaming resin layer 2 is 4000MPa to 9000MPa, and the difference between the tensile elastic moduli of the non-foaming resin layer 2 and the foaming resin layer 1 is 3000MPa or more.

If the tensile elastic modulus of the non-foamed resin layer 2 is 4000MPa or more, expansion and contraction of other layers such as the foamed resin layer 1 due to temperature change can be suppressed, and dimensional and shape stability can be imparted to the flooring material 10. On the other hand, if the tensile elastic modulus exceeds 9000MPa, the non-foamed resin layer 2 tends to become rigid and on the other hand, brittle. Therefore, when the non-foamed resin layer 2 is bent or tensile-stressed in the process of stacking the other layers such as the decorative layer 3 and the foamed resin layer 1 on the non-foamed resin layer 2, cracks or flaws may occur in the non-foamed resin layer 2.

The tensile elastic modulus of the non-foamed resin layer 2 was measured and calculated by the same method as that for measuring the tensile elastic modulus of the foamed resin layer 1 described above, to prepare the non-foamed resin layer 2 punched into a dumbbell-shaped test piece described in JIS K6732.

The non-foaming resin layer 2 preferably has a thermoplastic resin layer. As the thermoplastic resin forming the thermoplastic resin layer, polyvinyl chloride resin, polyvinyl acetate resin, polyvinyl alcohol resin and other polyethylene-based resins are preferable; polyolefin resins such as polyethylene resins, polypropylene resins, polystyrene resins, ethylene-vinyl acetate copolymer resins (EVA) and ethylene- (meth) acrylic resins; polyester resins such as polyethylene terephthalate resins (PET resins); single components and copolymers of thermoplastic resins such as acrylic resins, polycarbonate resins, polyurethane resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), acrylonitrile-styrene copolymers, and the like, or mixed resins thereof. Among them, the thermoplastic resin forming the thermoplastic resin layer is preferably a polyolefin resin, an acrylonitrile-butadiene-styrene copolymer, or a polyethylene-based resin.

In the flooring material 10 of the present embodiment, the non-foamed resin layer 2 contains an inorganic compound. This can greatly improve the tensile elastic modulus of the non-foamed resin layer 2 to 4000MPa or more, and further reduce the linear expansion coefficient. As a result, dimensional stability can be imparted to the flooring material 10.

The inorganic compound is not particularly limited, and is preferably selected from the group consisting of calcium carbonate, talc, silica, and mica, for example.

The blending amount (content) of the inorganic compound is preferably 20 to 80% by weight relative to the total components constituting the non-foamed resin layer 2. When the blending amount of the inorganic compound is less than 20% by weight, the non-foamed resin layer 2 tends to be incapable of achieving a significant improvement in tensile modulus and a sufficient decrease in linear expansion coefficient. If the amount of the inorganic compound exceeds 80% by weight, the elongation of the non-foamed resin layer 2 is insufficient. Therefore, when other layers such as the foamed resin layer 1 are laminated and processed on the non-foamed resin layer 2, cracks or processing defects tend to occur in the non-foamed resin layer 2. The amount of the inorganic compound to be blended is more preferably in the range of 40 to 75 wt%, still more preferably in the range of 50 to 75 wt%, still more preferably in the range of 60 to 70 wt%, with respect to the total components constituting the non-foamed resin layer 2.

In particular, from the viewpoint of excellent cost, the non-foaming resin layer 2 is preferably composed of 25 to 35% by weight of a polyvinyl chloride resin and 65 to 75% by weight of calcium carbonate.

The non-foaming resin layer 2 may be formed of 1 layer or may be a laminate of 2 or more layers. In particular, the non-foaming resin layer 2 is preferably a laminate of 2 or more layers, and at least 1 layer contains an inorganic compound. More specifically, the non-foaming resin layer 2 is preferably a laminate of 2 or more layers, at least 1 layer is a thermoplastic resin layer, and the other 1 layer is a thermoplastic resin layer containing an inorganic compound. By forming such a structure, a flooring material 10 having excellent impact resistance and further improved shape stability can be realized.

In the case where the non-foamed resin layer 2 has a plurality of thermoplastic resin layers, the types of resins forming the thermoplastic resin layers may be the same or different, and the thicknesses thereof may be the same or different.

The thickness of the non-foaming resin layer 2 is preferably 1 to 10mm, more preferably 1 to 5mm. When the thickness of the non-foamed resin layer 2 is within the above range, the flooring material 10 excellent in water resistance, moisture resistance, impact resistance and scratch resistance can be realized. The thickness of the non-foamed resin layer 2 is preferably smaller than that of the foamed resin layer 1 as described above.

(Adhesive layer)

In the flooring material 10, the foamed resin layer 1 and the non-foamed resin layer 2 are bonded with an adhesive layer. The pressure-sensitive adhesive layer is not particularly limited as long as the foamed resin layer 1 can be bonded to the non-foamed resin layer 2, and examples thereof include a heat-sensitive adhesive and a pressure-sensitive adhesive, and a hot-melt adhesive. The hot-melt adhesive is preferably a reactive hot-melt adhesive such as a urethane reactive hot-melt adhesive. The urethane-based reactive hot melt adhesive contains a functional group (isocyanate group) that reacts with moisture in its components, and after cooling and solidification, reacts with moisture adhering to the foamed resin layer 1 and the non-foamed resin layer 2, and moisture supplied by these. The urethane-based reactive hot melt adhesive has the following characteristics: after the reaction, the adhesive does not melt even when heated, and has high adhesive strength.

The non-foamed resin layer 2 may be an integral body having a decorative layer 3 described later formed on the surface thereof. Even if the resin layer 1 is an integral body, the resin layer 1 and the non-resin layer 2 are bonded together with an adhesive layer.

(Decorative layer 3)

The decorative layer 3 is a layer that imparts decorativeness to the flooring material 10. The decorative layer 3 may be, for example, a cover layer (field print layer) which is uniformly colored, a pattern layer which is formed by printing various patterns using ink and a printer, or a layer which is a combination of a cover layer and a pattern layer (corresponding to the pattern layer 32 shown in fig. 2). As another configuration, the decorative layer 3 may be a pattern itself formed by a transfer method or the like, a flat cut veneer or a saw plate obtained by slicing a wood material thinly, or a decorative sheet formed by providing a pattern on the colored base resin layer 31 or the base resin layer 31. And among them, more preferable is a decorative sheet shown below. Here, the "decorative sheet" refers to a sheet in which a layer constituting a pattern is formed on the base resin layer 31. The decorative sheet is preferably provided with a decorative layer 3A shown in fig. 2. That is, the decorative sheet preferably has a laminated structure including: a base resin layer 31 and a pattern layer 32; any layer including at least one of the transparent resin layer 34 and the surface protection layer 35; and an adhesive layer 33 for decorative layer for adhering the arbitrary layer to the base resin layer 31 and the pattern layer 32.

By providing the covering layer, the substrate on which the flooring material 10 is provided can be covered, and in the case where the foamed resin layer 1, the non-foamed resin layer 2, or the like is colored or color unevenness is present, an intended color can be provided to adjust the color of the surface.

Further, by providing the pattern layer, a decorative sheet can be provided with a stone pattern simulating the rock surface, such as a wood grain pattern or a marble pattern (e.g., lime Hua Dali stone pattern), a cloth pattern simulating a cloth pattern or a cloth-like pattern, a tile-like pattern, or a pattern such as a mosaic wood grain or a mosaic pattern formed by combining them. These patterns are formed by multicolor printing using a dedicated color, which is performed by preparing a plate of each color constituting the pattern, in addition to ordinary multicolor printing using primary colors of yellow, red, blue, and black.

As the ink composition used for the decorative layer 3, an ink composition obtained by appropriately blending a colorant such as a pigment or a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent, and the like with a binder resin is used. The binder resin is not particularly limited, and examples thereof include polyurethane resins, vinyl chloride/vinyl acetate copolymer resins, vinyl chloride/vinyl acetate/acrylic acid copolymer resins, acrylic resins, polyester resins, and nitrocellulose resins. As the binder resin, 1 kind or 2 or more kinds of binder resins may be used alone or in combination.

The colorant is preferably an inorganic pigment such as carbon black (ink), iron black, titanium white, antimony white, chrome yellow, titanium yellow, iron oxide red, cadmium red, ultramarine blue, cobalt blue, or the like; organic pigments or dyes such as quinacridone red, isoindolinone yellow, phthalocyanine blue, and the like; metallic pigments formed of flake foil of aluminum, brass, or the like; pearl luster (pearlescent) pigments formed by a scaly foil of titanium dioxide-coated mica, basic lead carbonate, or the like.

The thickness of the decorative layer 3 is preferably about 5 μm to 3 mm. In the case where the decorative layer 3 is the cover layer (in-situ printed layer), the pattern layer, or the pattern itself provided by a transfer method or the like, the thickness of the decorative layer 3 is preferably about 20 μm or less. In the case where the decorative layer 3 is the above-mentioned flat cut veneer or the above-mentioned sawn board, the thickness of the decorative layer 3 is preferably about 0.5mm to 3 mm. In the case where the decorative layer 3 is the decorative sheet, the thickness of the decorative layer 3 is preferably about 500 μm or less. When the thickness of the decorative layer 3 is within the above range, excellent design and covering properties can be provided to the floor material 10.

(Base resin layer 31)

The base resin layer 31 is a layer provided as needed, and is preferably a layer formed of a thermoplastic resin. The thermoplastic resin is preferably exemplified as the thermoplastic resin provided in the foamed resin layer 1. Among them, polyolefin resins are preferable, and polyethylene resins and polypropylene resins are more preferable.

The base resin layer 31 functions as a base sheet for forming a layer (pattern layer 32) constituting a pattern. The base resin layer 31 may be transparent or colored. The base resin layer 31 is preferably colored from the viewpoint of covering the substrate on which the flooring material 10A is provided. The coloring agent used for coloring the base resin layer 31 is preferably exemplified by coloring agents used for the decorative layer 3.

The thickness of the base resin layer 31 is preferably 10 μm to 50 μm, more preferably 30 μm to 100 μm, still more preferably 40 μm to 80 μm. If the thickness of the base resin layer 31 is within the above range, the handling of the flooring material 10A is easy, and the flooring material 10A does not become thicker than necessary.

Various additives such as a filler, a flame retardant, a lubricant, an antioxidant, an ultraviolet absorber, and a light stabilizer may be added to the base resin layer 31 as necessary.

(Transparent resin layer 34)

The transparent resin layer 34 is an arbitrary layer provided for protecting the embossed layer 32, and is preferably a layer formed of a thermoplastic resin. The thermoplastic resin is preferably a thermoplastic resin exemplified as the thermoplastic resin provided in the foamed resin layer 1 described above. Among them, polyolefin resins, more preferably polyethylene resins, polypropylene resins, and ionomer resins are preferable.

The transparent resin layer 34 is a transparent resin layer provided so that the pattern layer 32 can be seen through. Here, transparent means not only colorless transparent but also colored transparent and semitransparent concepts. In addition, various additives such as a filler, a flame retardant, a lubricant, an antioxidant, an ultraviolet absorber, and a light stabilizer may be added to the transparent resin layer 34 as necessary within a range that does not impair the transparency thereof.

The thickness of the transparent resin layer 34 is preferably 10 μm to 400 μm, more preferably 30 μm to 250 μm, still more preferably 50 μm to 100 μm. When the thickness of the transparent resin layer 34 is within the above range, the embossed layer 32 and the flooring material 10A can be protected, the handling is easy, and the flooring material 10 does not become thicker than necessary.

(Surface protective layer 35)

The surface protective layer 35 imparts surface characteristics such as impact resistance, load resistance, and scratch resistance to the flooring material 10A. The surface protection layer 35 is a layer provided as needed, and is provided on the outermost surface of the flooring material 10A.

The surface protection layer 35 is preferably composed of a cured product of a resin composition containing a curable resin. The cured product is formed by applying a resin composition containing a curable resin onto the pattern layer 32, or the transparent resin layer 34 or the decorative layer adhesive layer 33, which is preferably provided, and curing the resin composition. By containing the curable resin cured by crosslinking, the surface characteristics of the flooring material 10A can be improved.

The curable resin used for forming the surface protective layer 35 is preferably an ionizing radiation curable resin or a thermosetting resin, and may be a so-called hybrid type which uses a plurality of such curable resins, for example, an ionizing radiation curable resin and a thermosetting resin in combination.

Among them, the curable resin used for forming the surface protective layer 35 is preferably an ionizing radiation curable resin from the viewpoint of increasing the crosslinking density of the resin forming the surface protective layer 35 and improving the surface characteristics. There are also ionizing radiation curable resins that can be applied in a solvent-free manner, and among them, electron beam curable resins are more preferable from the viewpoint of ease of handling.

The ionizing radiation curable resin is a resin having energy quanta capable of crosslinking and polymerizing molecules in electromagnetic waves or charged particle beams, that is, a resin crosslinked or cured by irradiation with ultraviolet rays, electron beams, or the like. Specifically, the resin may be appropriately selected from polymerizable monomers and polymerizable oligomers or prepolymers which have been conventionally used as ionizing radiation curable resins.

The polymerizable monomer is preferably a (meth) acrylate monomer having a radically polymerizable unsaturated group in the molecule, and among these, polyfunctional (meth) acrylates are preferable. The polyfunctional (meth) acrylate is not particularly limited as long as it is a (meth) acrylate having 2 or more ethylenically unsaturated bonds in the molecule. These polyfunctional (meth) acrylates may be used singly or in combination of 2 or more.

Examples of the polymerizable oligomer include oligomers having a radically polymerizable unsaturated group in the molecule, such as epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, and polyether (meth) acrylate. Further, as other examples of the above-mentioned polymerizable oligomer, there are polybutadiene (meth) acrylate-based oligomer having a (meth) acrylate group in a side chain of polybutadiene oligomer and having a high hydrophobicity, silicone (meth) acrylate-based oligomer having a polysiloxane bond in a main chain, aminoplast resin (meth) acrylate-based oligomer obtained by modifying an aminoplast resin having many reactive groups in a small molecule, novolak-type epoxy resin, bisphenol-type epoxy resin, aliphatic vinyl ether, oligomer having a cationically polymerizable functional group in a molecule such as aromatic vinyl ether, and the like.

In the present embodiment, the above-described polyfunctional (meth) acrylate and the monofunctional (meth) acrylate may be used in combination as appropriate in order to reduce the viscosity thereof, so long as the purpose of the present embodiment is not impaired. These monofunctional (meth) acrylates may be used singly or in combination of 1 or more than 2.

Examples of the thermosetting resin include epoxy resin, phenol resin, urea resin, unsaturated polyester resin, melamine resin, alkyd resin, polyimide resin, silicone resin, hydroxy-functional acrylic resin, carboxyl-functional acrylic resin, amide-functional copolymer, and polyurethane resin.

The thermosetting resin is preferably a two-component curable resin, and more preferably a two-component curable resin of a polyol and an isocyanate. Examples of the polyol include acrylic polyol, polyester polyol, and epoxy polyol.

The isocyanate is not particularly limited, and may be, for example, a polyisocyanate having 2 or more isocyanate groups in the molecule. As the polyisocyanate, for example, aromatic isocyanates such as 2, 4-Toluene Diisocyanate (TDI), xylene Diisocyanate (XDI), naphthalene diisocyanate, and 4,4' -diphenylmethane diisocyanate; aliphatic (or alicyclic) isocyanates such as 1, 6-hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), methylene Diisocyanate (MDI), hydrogenated toluene diisocyanate, and hydrogenated diphenylmethane diisocyanate; and the like. Further, as the isocyanate, an adduct or a polymer of these various isocyanates, for example, an adduct of toluene diisocyanate, a toluene diisocyanate trimer (oligomer) or the like can be used.

The resin composition constituting the surface protective layer 35 may contain various additives as far as the performance thereof is not impaired.

Examples of the various additives include ultraviolet absorbers (UVA), light stabilizers (HALS, etc.), polymerization inhibitors, crosslinking agents, antistatic agents, adhesion improvers, antioxidants, leveling agents, thixotropic agents, coupling agents, plasticizers, antifoaming agents, fillers, solvents, and the like.

The thickness of the surface protective layer 35 is preferably 3 μm to 40 μm, more preferably 5 μm to 20 μm. When the thickness of the surface protective layer 35 is within the above range, excellent surface characteristics are obtained.

(Adhesive layer for decorative layer 33)

The adhesive layer 33 for a decorative layer is a layer which is provided when the base resin layer 31 and the transparent resin layer 34 are provided, and is provided as needed when the resin layers are laminated.

As the adhesive used in the adhesive layer 33 for a decorative layer, for example, urethane adhesive, acrylic/urethane adhesive, polyester urethane adhesive, polyamide adhesive, polystyrene adhesive, cellulose adhesive, and the like are preferable. These binders may be used singly or in the form of a mixture of 2 or more.

The thickness of the adhesive layer 33 for a decorative layer is preferably 1 μm to 30 μm, more preferably 3 μm to 15 μm. When the thickness of the decorative layer adhesive layer 33 is within the above range, good adhesion is obtained, and the floor material 10A does not become thicker than necessary.

The flooring material 10 or 10A of the present embodiment having the above layers is excellent in impact resistance, heat insulation, water resistance, load resistance, damage resistance, and ease of construction.

The thickness of the flooring material 10 or 10A is preferably 5mm or more, more preferably 6mm to 30mm, and even more preferably 9mm to 20mm, from the viewpoint of obtaining excellent impact resistance, heat insulation, water resistance, load resistance, and scratch resistance.

In addition, in view of ease of construction, the flooring material 10 or 10A is preferably formed to have the same thickness as a wooden flooring material installed in a place other than a water use place such as a living room or a corridor. The wood flooring material generally has a thickness of 8mm, 12mm, 15mm, etc., and 12mm is a standard thickness.

(Structure of tongue-and-groove portion (junction portion))

The main body B of the flooring material 10 of the present embodiment has a polygonal shape in a plan view. The polygon is not particularly limited, and examples thereof include a triangle, a square, a pentagon, and the like.

The tongue-and-groove processing is performed on the end of the main body B of the flooring material 10 in plan view, that is, on the end constituting at least one side of the polygon. In other words, a tongue portion or a groove portion engaged (fitted) with the tongue portion is provided at an end portion of the flooring material 10. Here, the tongue groove generally refers to a protrusion (tongue) or a groove-like recess (groove) formed in a shape capable of being fitted to each other on a side surface of a base material such as a floor board or a wood guard wall. The tongue groove processing for forming the tongue groove may be, for example, known processing such as tongue groove processing (this embodiment ( and )) processing and snap-in processing.

Fig. 3 is a sectional view showing the structure of the tongue-and-groove portion of the flooring material subjected to the tongue-and-groove process. As shown in fig. 3, the main body B of the floor material 10B and the main body B of the floor material 10C are fitted and joined to each other via the tongue groove 4 at one end of the polygonal shape. A groove-like recess 4B (groove) is formed in an end portion of the main body B of the floor material 10B. The concave portion 4b is formed along one side of the polygonal shape in a plan view. The recess 4B is a groove in a transverse U shape recessed toward the inside of the floor material 10B. Further, a protruding portion 4C (tongue portion) that can be fitted into the recess 4B is formed at an end portion of the main body B of the flooring material 10C that is joined to the recess 4B. The protruding portion 4c is a convex strip formed along one side of the polygonal shape. The tongue groove 4 is configured such that both the upper surface and the lower surface of the protruding portion 4C are in contact with the recess 4B when the flooring material 10B is fitted to the flooring material 10C. Such tongue-and-groove portions 4 are often referred to as tongue-and-groove.

Fig. 4 is a sectional view showing the structure of the tongue-and-groove portion of the floor material subjected to the snap-in process. As shown in fig. 4, the main body B of the floor material 10B and the main body B of the floor material 10C are fitted and joined to each other via the tongue groove 5 at one end portion constituting one side of the polygonal shape. A groove-like recess 5B (groove) is formed at an end of the floor material 10B. The concave portion 5b is formed along one side of the polygonal shape in a plan view. The concave portion 5b is an L-shaped groove with an open upper portion. Further, a protruding portion 5C (tongue portion) that can be fitted into the recess 5B is formed at an end portion of the main body B of the flooring material 10C that is joined to the recess 5B. The protruding portion 5c is a convex strip formed along one side of the polygonal shape. The tongue groove 5 is formed in such a structure that the lower surface of the protruding portion 5C is in contact with the recess 5B, out of the upper surface and the lower surface, when the flooring material 10B is fitted to the flooring material 10C. Such a tongue and groove portion 4 is commonly referred to as a snap-in.

According to the present embodiment, the tongue groove portion 4 is formed by fitting the concave portion 4B and the protruding portion 4C, or the tongue groove portion 5 is formed by fitting the concave portion 5B and the protruding portion 5C, whereby the floor material 10B and the floor material 10C can be joined to each other for construction. Specifically, the floor material 10B or 10C has a recess 4B or 5B formed at an end of at least 1 side constituting the polygon, and a protrusion 4C or 5C formed at an end of another side different from the 1 side.

In the present embodiment, as shown in fig. 3, a notched groove is formed in the bottom surface of the upper surface of the protruding portion 4C at the end of the non-foamed resin layer 2C of the floor material 10C, and the protruding portion 4C is formed at the upper portion. Further, at the end of the foamed resin layer 1C of the flooring material 10C, a notch groove of the upper surface is formed on the lower surface of the protruding portion 4C at the lower portion of the protruding portion 4C. In other words, the upper surface of the protruding portion 4c is constituted by the non-foamed resin layer 2c, and the lower surface of the protruding portion 4c is constituted by the foamed resin layer 1 c. In other words, the protruding portion 4c is constituted by both the foamed resin layer 1c and the non-foamed resin layer 2 c.

Further, at the end of the non-foamed resin layer 2B of the other flooring material 10B, a convex portion of the lower surface is formed on the upper surface of the concave portion 4B at the upper portion of the concave portion 4B. Further, at the end of the foamed resin layer 1B of the flooring material 10B, a convex portion of the upper surface is formed on the lower surface of the concave portion 4B at the lower portion of the concave portion 4B. In other words, the upper surface of the recess 4b is constituted by the non-foamed resin layer 2b, and the lower surface of the recess 4b is constituted by the foamed resin layer 1 b. In other words, the concave portion 4b is constituted by both the foamed resin layer 1b and the non-foamed resin layer 2 b.

With the structure in which the floor materials 10B and 10C are joined by the tongue-and-groove portion 4 having such a structure, even when the floor material 10B is away from the floor material 10C, the joined state (fitted state) is maintained by the presence of the cutout groove formed in the upper portion of the protruding portion 4C and the protruding portion formed in the upper portion of the recessed portion 4B, instead of the foamed resin layers 2B and 2C. Therefore, the foamed resin layers 1B and 1C as the lower layers of the non-foamed resin layers 2B and 2C are not exposed from the gap formed due to the deviation of the flooring material 10B from the flooring material 10C. As a result, the appearance of the flooring material is not impaired.

Further, according to the present embodiment, as shown in fig. 3, in the tongue groove portion 4, the concave portion 4b is constituted by the non-foamed resin layer 2b and the foamed resin layer 1b, and the protruding portion 4c is constituted by the non-foamed resin layer 2c and the foamed resin layer 1 c. The concave portion 4b and the protruding portion 4c constituting the tongue groove portion 4 are formed by the ends of the two foamed resin layers 1b and 1c and the non-foamed resin layers 2b and 2c in this manner. Therefore, the processing of the tongue groove portion 4 as the joint portion of the floor materials 10B and 10C becomes easy, and the tongue groove portion 4 of sufficient fitting strength can be achieved. Further, since the foam resin layers 1b and 1c also have cushioning properties for the fitting operation of the concave portion 4b and the convex portion 4c, cracks or chipping of the non-foam resin layers 2b and 2c having relatively thin thickness can be prevented, and easy construction can be realized.

In the structure shown in fig. 4, the concave portion 5b is also constituted by the non-foamed resin layer 2b and the foamed resin layer 1b, and the convex portion 5c is also constituted by the non-foamed resin layer 2c and the foamed resin layer 1c in the tongue groove portion 5. Therefore, the same effect as the structure shown in fig. 3 is exhibited.

In addition, as shown in fig. 3, when the flooring material 10B or 10C of the present embodiment is connected to the main body B of the other flooring material 10C by fitting the recess 4B and the protrusion 4C, a gap D of 10mm or less is preferably present between the foamed resin layer 1B of the main body B of the one flooring material 10B and the foamed resin layer 1C of the main body B of the other flooring material 10C. In order to prevent cracks or chipping of the tongue groove portion 4 and to maintain the fitting strength, the concave portion 4b is constituted by the non-foamed resin layer 2b and the foamed resin layer 1b, and the protruding portion 4c is constituted by the non-foamed resin layer 2c and the foamed resin layer 1 c. That is, part of the recess 4b and the projection 4c is constituted by the foamed resin layers 1b and 1 c.

By providing the gap D, when the floor material 10B and the floor material 10C are joined, the contact portion between the foamed resin layer 1B and the foamed resin layer 1C is only the contact portion between the portion constituting the recess 4B and the portion constituting the projection 4C. Therefore, contact between the foamed resin layers 1b and 1c is limited to a minimum, and contact between the ends of the foamed resin layers 1b and 1c is suppressed. Therefore, the floor rattling or squeaking caused by the contact of the foamed resin layers 1b and 1c with each other can be effectively suppressed.

If the gap D exceeds 10mm, the heat insulating property of the flooring material may be lowered or the strength may be lowered. A more preferable upper limit of the gap D is 6mm. The lower limit value of the gap D is preferably 0.5mm.

In the tongue groove portion 4 composed of the concave portion 4b and the protruding portion 4c, the ratio of the thickness of the foamed resin layers 1b and 1c to the thickness of the tongue groove portion 4 is not particularly limited as long as the tongue groove portion 4 can achieve a sufficient fitting strength and can suppress floor rattling or squeaking, but is preferably 40% to 60%, more preferably 45% to 55%.

In the structure shown in fig. 4, when one floor material 10B and the other floor material 10C are connected by fitting the concave portion 5B and the protruding portion 5C, a gap D of 10mm or less is also present between the foamed resin layer 1B of the one floor material 10B and the foamed resin layer 1C of the other floor material 10C. Therefore, the same effect as the structure shown in fig. 3 is exhibited.

(Method for producing flooring material 10)

The flooring material 10 or 10A of the present embodiment can be manufactured, for example, through the following steps.

A preparation step of preparing a non-foamed resin layer 2 and a foamed resin layer 1 having the following characteristics;

the non-foaming resin layer 2 contains an inorganic compound and has a tensile elastic modulus of 4000MPa to 9000MPa;

the difference between the tensile elastic moduli of the non-foamed resin layer 2 and the foamed resin layer 1 is 3000MPa or more;

The linear expansion coefficients of the non-foamed resin layer 2 and the foamed resin layer 1 are each 8×10 ^-5/DEG C or less, and the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer 2 from the linear expansion coefficient of the foamed resin layer 1 is greater than 3×10 ^-5/DEG C and 6×10 ^-5/DEG C or less;

a lamination step of laminating the decorative layer 3 or 3A, the non-foamed resin layer 2, and the foamed resin layer 1 in this order to form a flooring material body B; and

A tongue groove forming step of forming a protruding portion 4c (or 5 c) or a recessed portion 4B (or 5B) capable of being fitted with the protruding portion 4c (or 5 c) so as to be constituted of the non-foamed resin layer 2 and the foamed resin layer 1 at an end portion of the flooring material body B.

(Preparation step)

(Preparation step of foaming resin layer 1)

First, the foamed resin layer 1 is prepared. The foamed resin layer 1 was produced as described above in the following manner: the foaming is preferably carried out at a foaming ratio of 5 to 20 times by a bead method, or a film forming method such as an extrusion film forming method or a calendaring film forming method using a resin composition for forming a foamed resin layer, and the compression elastic modulus is 15MPa or more and the tensile elastic modulus is 30 to 300MPa.

The expansion ratio, compression elastic modulus, or tensile elastic modulus of the foamed resin layer 1 can be appropriately adjusted by the foaming temperature at the time of foaming, the kind of resin, the amounts of the foaming agent and the plasticizer, and the like.

(Preparation step of non-foaming resin layer 2)

Next, the non-foaming resin layer 2 is prepared. The non-foaming resin layer 2 is produced in the following manner: the film is formed by a film forming method such as an extrusion film forming method or a rolling film forming method by using a T die, and the tensile elastic modulus is 4000MPa to 9000MPa or more.

The tensile elastic modulus of the non-foamed resin layer 2 can be appropriately adjusted by the kind of resin, the kind and amount of inorganic compound, and the like.

(Lamination step)

(Step of Forming decorative layer 3 or decorative layer 32)

The decorative layer 3 or the pattern layer 32 is formed using the ink composition on the non-foamed resin layer 2 or the base resin layer 31 provided as needed. The ink composition may be applied by, for example, gravure printing, offset printing, screen printing, flexography, inkjet printing, or the like. In the case of forming a masking layer (in-situ printed layer), it is sufficient to form the masking layer by various coating methods such as gravure coating, bar coating, roll coating, reverse roll coating, comma coating, and the like.

(Step of laminating transparent resin layer 34)

The transparent resin layer 34 is preferably formed by the decorative adhesive layer 33 after the pattern layer 32 is formed. The adhesive layer 33 for the decorative layer may be formed by various coating methods such as gravure coating, bar coating, roll coating, reverse roll coating, comma coating, and the like, an extrusion film forming method using a T die, and the like. The transparent resin layer 34 is laminated while being formed by an extrusion film forming method using a T die; the film may be obtained by preliminarily forming a film by a film forming method such as an extrusion film forming method or a calender film forming method using a T die, or may be formed by a method of laminating the film by a dry lamination method or a thermal lamination method.

(Step of forming surface protective layer 35)

The surface protection layer 35 may be formed by the following method. First, after the step of forming the pattern layer 32 or after the step of laminating the transparent resin layer 34, the curable resin composition is applied on the pattern layer 32 or on the transparent resin layer 34. At this time, the uncured resin layer is formed by coating in a known manner such as gravure coating, bar coating, roll coating, reverse roll coating, comma coating, etc., so that the thickness after curing is about 3 μm to 40 μm. Then, heat is applied to the uncured resin layer, or ionizing radiation such as electron beam or ultraviolet light is irradiated to cure the uncured resin layer, whereby the surface protective layer 35 can be formed.

In the case of thermally curing the above-mentioned uncured resin layer, the heating temperature is appropriately determined according to the resin used. In the case of using an electron beam as the ionizing radiation, the acceleration voltage can be appropriately selected according to the resin to be used and the thickness of the layer, and it is generally preferable to cure the uncured resin layer at an acceleration voltage of about 70kV to 300 kV. The irradiation dose is preferably an amount at which the crosslinking density of the resin layer is saturated, and is usually selected in the range of 5 to 300kGy (0.5 to 30 Mrad), preferably 10 to 50kGy (1 to 5 Mrad).

The electron beam source is not particularly limited, and various electron beam accelerators such as a Cockroft-Walton type, VAN DE GRAAFF type, a resonant transformer type, an insulating core transformer type (insulating core transformer type), a linear type, a ground nano type (dynamitron type), and a high frequency type can be used.

When ultraviolet rays are used as the ionizing radiation, ultraviolet rays including ultraviolet rays having a wavelength of 190nm or more and 380nm or less are irradiated. The ultraviolet source is not particularly limited, and for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a carbon arc lamp, or the like is used.

(Bonding step of non-foaming resin layer 2 and decorative layer 3)

In the case where the decorative layer 3 is the decorative sheet, the non-foamed resin layer 2 and the decorative layer 3 may be bonded using, for example, a hot melt adhesive or the like in addition to a heat-sensitive adhesive or a pressure-sensitive adhesive. As the hot-melt adhesive, for example, a urethane-based reactive hot-melt (hereinafter referred to as "PUR-based adhesive") and other reactive hot-melt adhesives are preferable. The PUR-based adhesive contains a functional group (isocyanate group) that reacts with moisture in the component, and after cooling and solidification, reacts with moisture adhering to the substrate or the decorative sheet, and moisture supplied by the moisture. Has the following characteristics: after the reaction, the adhesive does not melt even when heated, and has high adhesive strength.

(Bonding step of foaming resin layer 1 and non-foaming resin layer 2)

The adhesive shown in the step of adhering the non-foamed resin layer 2 and the decorative layer 3 may be used for adhering the foamed resin layer 1 and the non-foamed resin layer 2, which are obtained in the step of preparing the foamed resin layer 1, to each other.

(Tongue groove Forming step)

The protruding portion 4c (or 5 c) or the recessed portion 4B (or 5B) is formed at the end of the flooring material body B manufactured through the preparation step and the lamination step. The method of forming the protruding portion 4c (or 5 c) or the recessed portion 4b (or 5 b) may be a conventionally known method of forming a tongue groove portion.

In a preferred example of the flooring material 10 of the present embodiment, the flooring material 10 has the decorative layer 3, the non-foamed resin layer 2, and the foamed resin layer 1, and the ratio of the total thickness of the decorative layer 3 and the non-foamed resin layer 2 to the thickness of the foamed resin layer 1 and the compression elastic modulus of the foamed resin layer 1 are respectively defined at predetermined values, so that the flooring material is excellent in water resistance and heat insulation properties, and also excellent in load resistance.

(Summary)

From the above, one embodiment of the present invention includes the following technical features.

[1] A floor material comprising a decorative layer, a non-foamed resin layer and a foamed resin layer laminated in this order, wherein the non-foamed resin layer and the foamed resin layer each have a linear expansion coefficient of 8X 10 ^-5/DEG C or less, the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer from the linear expansion coefficient of the foamed resin layer is greater than 3X 10 ^-5/DEG C and 6X 10 ^-5/DEG C or less, the non-foamed resin layer contains an inorganic compound and has a tensile elastic modulus of 4000MPa to 9000MPa, the difference between the tensile elastic moduli of the non-foamed resin layer and the foamed resin layer is 3000MPa or more, and the floor material comprises a tongue portion formed at an end portion of the floor material or a groove portion capable of being fitted to the tongue portion, and the tongue portion and the groove portion are composed of the non-foamed resin layer and the foamed resin layer.

[2] The flooring material according to item [1], wherein when one flooring material is connected to another flooring material by fitting the tongue portion and the groove portion, a gap of 10mm or less is present between the foamed resin layer of the one flooring material and the foamed resin layer of the other flooring material.

[3] The flooring material according to [1] or [2], wherein the resin component of the non-foamed resin layer is a thermoplastic resin selected from the group consisting of polyvinyl chloride-based resins, polypropylene-based resins, and acrylonitrile-butadiene-styrene copolymers.

[4] The flooring material according to any one of [1] to [3], wherein the inorganic compound contained in the non-foaming resin layer is selected from the group consisting of calcium carbonate, talc, silica and mica.

[5] The floor material according to any one of [1] to [4], wherein the amount of the inorganic compound blended in the non-foamed resin layer is 20 to 80% by weight relative to the total components constituting the non-foamed resin layer.

[6] The flooring material according to any one of [1] to [5], wherein the non-foaming resin layer is composed of 25 to 35% by weight of a polyvinyl chloride resin and 65 to 75% by weight of calcium carbonate.

[7] The flooring material according to any one of [1] to [6], wherein the foamed resin layer is a polystyrene resin layer, and the foaming ratio is 5 to 20 times.

[8] The flooring material according to any one of [1] to [7], wherein the foamed resin layer is thicker than the non-foamed resin layer.

[9] The flooring material according to any one of [1] to [8], wherein the groove portion is a groove-shaped recess having a U-shape in a lateral direction, and the tongue portion is a ridge portion fitted into the recess portion.

[10] The floor material according to any one of [1] to [8], wherein the groove portion is an L-shaped groove-shaped concave portion having an open upper portion, and the tongue portion is a ridge portion capable of being fitted into the concave portion.

[11] The floor material according to any one of [1] to [10], wherein, when one floor material is connected to another floor material by fitting the tongue portion and the groove portion, a ratio of a thickness of the foamed resin layer of the one floor material and a thickness of the foamed resin layer of the other floor material to a thickness of a tongue groove portion formed by the tongue portion and the groove portion is 40% to 60%.

[12] The flooring material according to any one of [1] to [11], wherein the decorative layer has a laminated structure comprising: a base resin layer and a pattern layer; an arbitrary layer including at least one of a transparent resin layer and a surface protective layer; and an adhesive layer for a decorative layer for adhering the arbitrary layer to the base resin layer and the pattern layer.

[13] The flooring material according to any one of [1] to [12], wherein the foamed resin layer has a compression elastic modulus of 15MPa or more.

[14] A method of manufacturing a flooring material, comprising:

a preparation step of preparing a non-foamed resin layer and a foamed resin layer having the following characteristics;

The linear expansion coefficients of the non-foamed resin layer and the foamed resin layer are each 8×10 ^-5/DEG C or less, and the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer from the linear expansion coefficient of the foamed resin layer is greater than 3×10 ^-5/DEG C and 6×10 ^-5/DEG C or less;

The non-foaming resin layer contains an inorganic compound and has a tensile elastic modulus of 4000MPa to 9000MPa;

[15] The method for producing a floor material according to item [14], wherein the tongue-and-groove portion forming step includes the steps of: the tongue portion or the groove portion is formed so that a gap of 10mm or less is generated between the foamed resin layer of the one flooring material body and the foamed resin layer of the other flooring material body when the one flooring material body and the other flooring material body are connected by fitting the tongue portion and the groove portion.

Examples

The present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

(Evaluation and measurement method)

The flooring materials obtained in examples and comparative examples were evaluated and measured by the following methods.

(Evaluation of tensile elastic modulus)

< Preparation of test piece >)

Each test piece of the foamed resin layer and the non-foamed resin layer was cut out from the flooring materials obtained in examples and comparative examples, and an electric saw was used. Further, each test piece was cut out so as to form a dumbbell-shaped test piece described in JIS K6732 (1996).

Then, the test piece was produced by removing the factor (serration) which was the factor of the resistance in the stretching direction measurement with sandpaper.

< Measurement Condition >

The measurement conditions were set according to the records of JIS K7161-1994 (ISO 527-1:1993).

Specifically, the dimensions of the test piece were measured by measuring the width and thickness using a digital vernier caliper capable of reading 0.01mm, and the cross-sectional area Smm ² of the test piece was calculated.

For the test piece, both ends in the longitudinal direction were fixed by a jig and measured. The distance between the clamps was measured by the digital vernier caliper, and the initial length L ₀ =80±0.8mm.

The tensile stress was set in MPa units for the tensile force per unit area calculated based on the initial cross-sectional area according to the same JIS standard calculation method. Measurement of tensile elastic modulus the tensile elastic modulus E was calculated by dividing the difference Δp (σ ₁-σ₂) between the stresses (loads) corresponding to the tensile deformation values (elongation) ε ₁ =0.10% and ε ₂ =0.25% by the difference Δe (ε ₁-ε₂) between deformations, according to the same JIS standard.

The stretching speed was measured by using a measuring apparatus in accordance with the same JIS standard, and the measurement was performed at a setting of 50 mm/min. The initial load point is set to be equal to or more than 0.3N, and the initial load point is used as the starting point of calculation instead of the test starting point. In the test, the measurement using TENSILON RTC-1310A manufactured by A & D corporation was performed 3 times, and an average value at 3 points was recorded.

(Evaluation of linear expansion coefficient)

A test piece in the form of a rectangular parallelepiped having a longitudinal direction of 100mm and a transverse direction of 300mm was cut out from each layer of the floor material, and the temperature of the test piece was stabilized at 0℃and 40℃by using a constant temperature bath (ESPEC Corp, building-in Chamber TBL-6E20W0P 2T). Then, the dimensions of the total 3 parts of the center and the parts from the end to the 50mm center side were measured with respect to the width and length of the test piece at this time using a digital vernier caliper read to 0.01 mm. The dimensional change was calculated from the length dimensions obtained at each temperature and each position, and the value obtained by dividing the dimensional value at 0 ℃ was set as the dimensional change rate: Δl. By dividing Δl obtained above by the temperature change amount: delta T is calculated to calculate the dimensional change amount per unit temperature of each measurement site. Next, 3 test pieces cut out at 3 positions in the longitudinal direction of the flooring material were prepared, the dimensional change amount per unit temperature was measured for each test piece in the above-described manner, and the value obtained by arithmetic averaging them was used as the linear expansion coefficient.

(Construction quality)

As shown in 501 of fig. 5, the following items were evaluated by placing the floor materials 20a to 20d 4 each having a dimension width of 450mm and a length of 900mm on a mortar (cured for 1 week) coated with the urethane-based adhesive 30 at a pitch of 225mm and then leaving the mortar in an environment of 40 ℃ x3 days from 5 ℃ x3 days. The floor materials obtained in each of the examples and comparative examples were provided with 1 set of tongue and groove portions on each of the short side and long side.

Level difference "

And (3) the following materials: 0.1mm or less

O: more than 0.1mm and less than 0.3mm

Delta: more than 0.3mm and less than 0.5mm

X: exceeding 0.5mm

Jacking up "

O: visually indistinguishable

Delta: can be visually distinguished but is slightly and not obvious

X: can be easily distinguished visually

Floor sound "

O: even if a person steps on the floor, no floor sound is generated

X: floor sound is heard when the person steps on

Tongue and groove chimerism "

O: easy fitting, and no crack or defect of tongue groove

X: the fitting requires attention, and there are cracks and defects in the tongue groove portion.

As shown in 502 of fig. 5, the "step" refers to that the fitting portion a of the flooring materials 20a and 20c floats upward when the flooring materials 20a and 20c are fitted. As shown in 503 of fig. 5, "jack-up" refers to a state in which the outer end portion of one or both of the fitting portion a and the floor materials 20a and 20c bulges when the floor materials 20a and 20c are fitted.

Example 1

A stone pattern layer having a thickness of 2 μm was formed on a colored polypropylene resin film (thickness; 60 μm, color; white) by gravure printing using an ink composition (acrylic urethane). Then, an adhesive layer having a thickness of 2 μm was formed using a urethane-based dry lamination adhesive, and a transparent polypropylene resin film (thickness: 80 μm) was dry laminated on the patterned layer.

On the transparent polypropylene resin film, a primer layer having a thickness of 1 μm was formed using a two-component curable polyurethane resin. Then, an electron beam curable resin composition (acrylic acid ester based) was applied to the primer layer by gravure printing at a coating weight of 15g/m ² to form a coating film, and the coating film was crosslinked and cured by irradiation with an electron beam to form a surface protective layer (thickness: 15 μm), and a decorative sheet (thickness: 160 μm) was produced to form a decorative layer.

Next, a vinyl chloride resin sheet (tensile modulus: 6500MPa, thickness: 2.7 mm) containing 69 mass% of calcium carbonate was prepared as a non-foamed resin layer, and the non-foamed resin layer and the decorative sheet were bonded by dry lamination with a urethane-based dry lamination adhesive so as to face the colored polypropylene resin film (base resin layer) of the decorative sheet.

Next, as a foamed resin layer, a foamed resin layer (expansion ratio: 10 times, compression elastic modulus: 43MPa, tensile elastic modulus: 100MPa, thickness: 9 mm) produced by bead method using EPS resin (foaming agent; butane (7 parts by mass based on 100 parts by mass of polystyrene resin), plasticizer, liquid paraffin (0.15 parts by mass based on 100 parts by mass of polystyrene resin)) was prepared, and a non-foamed resin layer and a foamed resin layer to which the decorative sheet was adhered were adhered using a PUR-based adhesive to produce a floor material.

And then, a tongue-and-groove machine is used for processing the foamed resin layer and the non-foamed resin layer, and a tongue-and-groove is arranged. The results of evaluating the obtained flooring materials are shown in table 1.

Examples 2 to 5 and comparative examples 1 to 2

A flooring material was produced in the same manner as in example 1, except that the foamed resin layer and the non-foamed resin layer shown in table 1 were replaced. The results of evaluating the obtained flooring materials are shown in table 1.

Example 6

A flooring material was produced in the same manner as in example 1, except that the tongue-and-groove process was adjusted so that the amount of gap between the foamed resin layers when the flooring materials were fitted to each other was 0.5mm.

Example 7

A flooring material was produced in the same manner as in example 1, except that the tongue-and-groove process was adjusted so that the amount of gap between the foamed resin layers when the flooring materials were fitted to each other was 10 mm.

Example 8

A flooring material was produced in the same manner as in example 1, except that the tongue-and-groove process was adjusted so that the amount of gap between the foamed resin layers when the flooring materials were fitted to each other was 0 mm.

Comparative example 3

A floor material was produced in the same manner as in example 1, except that the tongue groove portion was adjusted so as to be composed of only a non-foamed resin layer.

TABLE 1

As shown in table 1, when the following conditions (a) to (c) were satisfied, the evaluation of "level difference", "jack-up" and "tongue groove fitting" was good. (a) The linear expansion coefficients of the non-foamed resin layer and the foamed resin layer are each 8×10 ^-5/DEG C or less, and the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer from the linear expansion coefficient of the foamed resin layer is greater than 3×10 ^-5/DEG C and 6×10 ^-5/DEG C or less. (b) The non-foaming resin layer contains an inorganic compound, and has a tensile elastic modulus of 4000MPa to 9000MPa, and the difference between the tensile elastic moduli of the non-foaming resin layer and the foaming resin layer is 3000MPa or more. (c) The tongue portion and the groove portion are constituted of a non-foamed resin layer and a foamed resin layer.

Further, it was found that, when the following condition (d) was satisfied in addition to the conditions (a) to (c), the evaluation of "floor sound" was also good in addition to the evaluation of "step difference", "jack up" and "tongue groove fitting". (d) The clearance between the foamed resin layer of one floor material and the foamed resin layer of the other floor material in the tongue groove portion is 10mm or less.

Description of the reference numerals

1.1 B, 1c foamed resin layer

2.2 B, 2c non-foaming resin layer

3. 3A decorative layer

4.5 Tongue groove portion

4B, 5b recess (groove)

4C, 5c projection (tongue)

10. 10A, 10B, 10C flooring material

B main body (floor material main body)

Claims

1. A floor material is provided with: a flooring material body in which a decorative layer, a non-foaming resin layer and a foaming resin layer are laminated in this order,

The linear expansion coefficients of the non-foaming resin layer and the foaming resin layer are each 8×10 ^-5/DEG C or less, and the value obtained by subtracting the linear expansion coefficient of the non-foaming resin layer from the linear expansion coefficient of the foaming resin layer is more than 3×10 ^-5/DEG C and 6×10 ^-5/DEG C or less,

The difference between the tensile elastic moduli of the non-foamed resin layer and the foamed resin layer is 3000MPa or more,

The flooring material has a tongue portion formed at an end of the flooring material body, or a groove portion capable of being fitted to the tongue portion,

The tongue portion and the groove portion are constituted by the non-foamed resin layer and the foamed resin layer.

2. The flooring material of claim 1, wherein when one flooring material body is connected to another flooring material body by fitting the tongue portion to the groove portion, a gap of 10mm or less is present between the foamed resin layer of the one flooring material body and the foamed resin layer of the other flooring material body.

3. The flooring material according to claim 1 or 2, wherein the resin component of the non-foaming resin layer is a thermoplastic resin selected from the group consisting of polyvinyl chloride-based resin, polypropylene-based resin, and acrylonitrile-butadiene-styrene copolymer.

4. The flooring material according to claim 1 or 2, wherein the inorganic compound contained in the non-foaming resin layer is selected from the group consisting of calcium carbonate, talc, silica and mica.

5. The flooring material according to claim 1 or 2, wherein the inorganic compound in the non-foamed resin layer is compounded in an amount of 20 to 80% by weight relative to the total components constituting the non-foamed resin layer.

6. The flooring material according to claim 1 or 2, wherein the non-foaming resin layer is composed of 25 to 35% by weight of polyvinyl chloride-based resin and 65 to 75% by weight of calcium carbonate.

7. The flooring material according to claim 1 or 2, wherein the foamed resin layer is a polystyrene resin layer, and the foaming ratio is 5 to 20 times.

8. The flooring material of claim 1 or 2, wherein the foamed resin layer is thicker than the non-foamed resin layer.

9. The flooring material according to claim 1 or 2, wherein the groove portion is a groove-shaped recess portion having a transverse U-shape,

The tongue portion is a protruding strip fitted into the recess.

10. The flooring material according to claim 1 or 2, wherein the groove is an L-shaped groove-like recess with an open upper portion,

The tongue portion is a protruding strip capable of being fitted into the recess portion.

11. The flooring material according to claim 1 or 2, wherein when one flooring material is connected to the other flooring material by the engagement of the tongue portion with the groove portion,

The ratio of the thickness of the foamed resin layer of the one flooring material and the foamed resin layer of the other flooring material to the thickness of the tongue-and-groove portion constituted by the tongue portion and the groove portion is 40% to 60%.

12. The flooring material according to claim 1 or 2, wherein the decorative layer has a laminated structure comprising: a base resin layer and a pattern layer; an arbitrary layer including at least one of a transparent resin layer and a surface protective layer; and an adhesive layer for a decorative layer for adhering the arbitrary layer to the base resin layer and the pattern layer.

13. The flooring material according to claim 1 or 2, wherein the foamed resin layer has a compressive elastic modulus of 15MPa or more.

14. A method of manufacturing a flooring material, comprising:

The linear expansion coefficients of the non-foamed resin layer and the foamed resin layer are each 8×10 ^-5/DEG C or less, and the value obtained by subtracting the linear expansion coefficient of the non-foamed resin layer from the linear expansion coefficient of the foamed resin layer is greater than 3×10 ^-5/DEG C and 6×10 ^-5/DEG C or less,

The difference between the tensile elastic moduli of the non-foamed resin layer and the foamed resin layer is 3000MPa or more;

15. The method for producing a floor material according to claim 14, wherein the tongue-and-groove portion forming step includes the steps of: the tongue portion or the groove portion is formed so that a gap of 10mm or less is generated between the foamed resin layer of the one flooring material body and the foamed resin layer of the other flooring material body when the one flooring material body and the other flooring material body are connected by fitting the tongue portion and the groove portion.