JP2003118053A - Decorative sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decorative sheet including a foamable resin layer, excellent in the whiteness, surface smoothness and chemical embossing properties in its foame layer along with capacities such as foamability, curling resistance, scratch resistance or the like, having good design effect, not generating harmful gas such as chlorine gas or the like if burnt and excellent in safety and environmental properties. SOLUTION: For example, the decorative sheet is a laminate obtained by laminating at least the foamable resin layer 2 and a pattern ink layer (containing a foaming inhibitor) 4 on a substrate (backing layer) to constitute a non-foamed decorative sheet. A resin composition, which is based on an olefinic copolymer resin and contains at least ADCA with a median particle size of below 20 μm added as a foaming agent, is used in the foamable resin layer 2 and foamed under heating to obtain the foamed decorative sheet 10. If necessary, other foaming agent, a foamed cell adjusting agent, a fire retardant, a lubricant, a colorant, a fluorescent brightener or the like can be appropriately added to the foamable resin layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative sheet, and more specifically, it is used for interior materials of buildings such as wallpaper, floor materials and ceiling materials, and other surface coating materials for furniture, home appliances, leather, book covers, etc. It can be used in a wide range of applications such as surface materials, and a foamed resin layer is laminated on the intermediate layer, etc., and has good touch and various performances. In addition, the foamed resin layer has excellent whiteness and surface smoothness (smoothness) The present invention relates to a decorative sheet that has a good printing effect for pictures and the like, and does not generate a harmful gas even when incinerated at the time of disposal after use, and is excellent in safety and environmental suitability.

[0002]

2. Description of the Related Art Conventionally, a decorative sheet which is used as an interior material for buildings such as wallpaper, floor material, and ceiling material, and other surface coating material for furniture, home appliances, etc., in which a foamed resin layer is laminated as an intermediate layer. For example, a backing layer such as paper or cloth is laminated on a resin sheet formed by blending a blowing agent with a plasticizer, a stabilizer, etc. in a polyvinyl chloride resin, and a printing layer such as a pattern is provided on the surface and heated. Foamed decorative sheets are known.

[0003]

However, in the conventional decorative sheet as described above, the foamed resin layer, which is the main component of the decorative sheet, has a polyvinyl chloride resin as the main component, and the addition of a plasticizer is essential. As a result of the plasticizer migrating to the surface after long-term use and causing stickiness on the surface, it is easy for dirt to adhere, and at the part where the plasticizer has come off, there is a problem that it becomes hard and easily cracks at low temperatures. .

Further, such a decorative sheet made of polyvinyl chloride resin has a problem of causing gas poisoning at the time of fire because it produces a harmful gas such as chlorine gas and hydrochloric acid gas when burning. Also, after long-term use,
There was also a problem of causing air pollution and environmental pollution during incineration.

The present invention has been made to solve the above problems, and its purpose is to provide interior materials for buildings such as wallpaper, floor materials, and ceiling materials, and other furniture and home appliances. It is a decorative sheet that can be used in a wide range of applications such as surface coating materials, and has a foamable resin layer laminated on its intermediate layer, and its foamability, processability, curl resistance, scratch resistance, flame resistance, etc. Good performance, good foaming suppression effect when chemical embossing is applied, and the foamable resin layer after foaming has excellent whiteness and surface smoothness (smoothness of the surface), and good printing effect for patterns etc. , The surface does not become sticky due to migration of plasticizer even after long-term use, and it does not generate toxic gases such as chlorine even when burned due to fire or incineration after use, performance and design Safety with sex,
It is to provide a decorative sheet having excellent environmental suitability with high productivity.

[0006]

The above-mentioned problems can be solved by the present invention described below. That is, the invention described in claim 1 is a decorative sheet obtained by heat-foaming a laminate in which at least a foamable resin layer and a pattern ink layer are laminated on a substrate (backing layer), the foamable resin layer Is a resin composition comprising an olefin-based copolymer resin as a main component and at least azodicarbonamide as a foaming agent added thereto, and the median diameter of the azodicarbonamide is less than 20 μm. And a makeup sheet.

As the olefinic copolymer resin of the foamable resin layer, ethylene, propylene, butene-1, etc., other α-olefins and various acrylic acid esters,
A copolymer resin obtained by copolymerizing methacrylic acid ester, acrylic acid, methacrylic acid, vinyl acetate and the like can be used alone or in combination.

As the foaming agent to be added to the olefin copolymer resin, a known foaming agent which decomposes by heat to generate gas can be used. For example, azodicarbonamide (hereinafter abbreviated as ADCA), 4 , 4'-oxybis (benzenesulfonyl hydrazide) (hereinafter OBS
H), paratoluenesulfonyl hydrazide (hereinafter T
SH), dinitropentamethylenetetramine (hereinafter D
PT) and the like. Among these, ADCA is
It can be preferably used because it has excellent foaming properties and, even when chemical embossing is performed, it has an excellent foaming suppressing effect by the foaming suppressing agent. However, when ADCA is used as the foaming agent, the foamable resin layer after heat-foaming tends to be yellowish, and fine crushed irregularities are generated on the surface to impair the surface smoothness (surface smoothness). There is a problem in that the printing effect such as a picture is deteriorated and the appearance is deteriorated. As a method of preventing the yellowing and increasing the whiteness, for example, there is a method of adding a white pigment or a fluorescent whitening agent, and thereby the whiteness can be improved to some extent, but only by adding a white pigment or a fluorescent whitening agent. However, it was not always sufficient, and in particular, the surface smoothness could not be improved.

As a means for solving such a problem, A
It has been found that it is effective to reduce the median diameter of DCA to less than 20 μm, and in the present invention, at least ADCA is used as a foaming agent, and the median diameter is 20
By setting the thickness to less than μm, it is possible to maintain the excellent foaming property and the foaming suppressing effect of the foaming inhibitor, and to improve the whiteness and surface smoothness of the foamable resin layer after foaming. . Therefore, when the median diameter of ADCA is 20 μm or more, the foamable resin layer after foaming becomes yellowish and the surface smoothness is poor, which is not preferable. In addition, AD
The lower limit of the median diameter of CA is not particularly limited, and as the median diameter becomes smaller, the foaming temperature tends to decrease and the foamability tends to improve, and the whiteness and surface smoothness of the foamable resin layer after foaming ( The smoothness of the surface) and the effect of suppressing foaming by the foaming inhibitor also tend to improve slightly, and good performance is maintained. For example, the above-mentioned performance is good even when the median diameter is 1 μm, and it can be further reduced to 0.5 μm. If the median diameter is as small as 0.5 μm, the above performance problem does not occur, but secondary agglomeration is likely to occur, so that the performance improvement tendency is not recognized and it is not necessarily a good measure from the economical point of view.

Therefore, by adopting the above-mentioned constitution, since the olefinic copolymer resin is used as the main component of the foamable resin layer which is the main component of the decorative sheet, it is not necessary to add a plasticizer, The plasticizer migrates to the surface to make it easy to stain the surface, hardens the foamable resin layer, and does not cause cracks, has stable flexibility for a long period of time, has other performance, and burns. Even if it does not generate harmful gases such as chlorine-based ones, it can be made into a decorative sheet excellent in safety and environmental suitability. Further, since at least ADCA is used as the foaming agent of the foamable resin layer and the median diameter thereof is less than 20 μm, as described above, the excellent foamability and the foam suppressing effect of the foam suppressing agent are maintained. It is possible to prevent the foamable resin layer after heating and foaming from becoming yellowish and to have a good whiteness, and also to obtain a decorative sheet having good surface smoothness and scratch resistance.

According to a second aspect of the present invention, the olefin-based copolymer resin is ethylene and the general formula "CH ₂ = CR ₁
COOR ₂ "wherein R ₁ is H or CH ₃ , and R is
₂ is an alkyl group. ] An ethylene / acrylic copolymer resin obtained by copolymerizing an acrylic ester or a methacrylic ester represented by: or a mixed resin thereof, or an ethylene copolymer resin obtained by blending an ethylene-vinyl acetate copolymer resin therewith. The ethylene-based copolymer resin has a MFR of 4.5 or less, and the content of the comonomer relative to ethylene in the ethylene-based copolymer resin is 17 to 24% by weight. It consists of a decorative sheet.

In the present invention, MFR (Melt Flow Ra
te) is measured according to condition 4 in Table 1 of JIS K7210 (flow test method for thermoplastics). The content of the comonomer in the ethylene-based copolymer resin is obtained by blending ethylene-vinyl acetate copolymer resin in addition to various acrylic acid esters or various methacrylic acid esters represented by the general formula CH ₂ = CR ₁ COOR _2. If present, vinyl acetate is also included. The ethylene-vinyl acetate copolymer resin is blended in order to improve physical properties such as flexibility and curl resistance.

The various acrylic acid esters or various methacrylic acid esters of the above-mentioned comonomers are not particularly limited, and examples thereof include methyl methacrylate, methyl acrylate, ethyl acrylate, butyl methacrylate, hexyl acrylate, lauryl methacrylate, and acrylic. Stearyl acid and the like can be preferably used.

The ethylene / acrylic copolymer resin, a mixed resin thereof, or an ethylene copolymer resin obtained by blending an ethylene / vinyl acetate copolymer resin with the ethylene / acrylic copolymer resin is processed to form a film and is processed into a decorative sheet. In view of curl resistance, foaming resistance, scratch resistance, flame retardancy, touch, etc., the comonomer content relative to ethylene is 1
It is preferably 7 to 24% by weight, and its MFR
Is preferably 4.5 or less. If the MFR of the ethylene-based copolymer resin exceeds 4.5, the processability during film formation decreases, and if the content of the comonomer is less than 17% by weight, the curl resistance and flame retardancy are reduced. Is reduced,
When the content of the comonomer exceeds 24% by weight, workability during film formation, scratch resistance and the like are deteriorated, which is not preferable.

Therefore, by adopting the above-mentioned constitution, in addition to the function and effect of the invention described in claim 1, ethylene and the general formula "CH ₂ = CR" are added to the olefin copolymer resin of the foamable resin layer. ₁ COOR ₂ "wherein R ₁ is H or CH ₃ and R ₂ is an alkyl group. ] An ethylene-acrylic copolymer resin obtained by copolymerizing an acrylic ester or a methacrylic ester represented by or a mixed resin thereof, or an ethylene copolymer resin obtained by blending an ethylene-vinyl acetate copolymer resin therewith. And the MFR of the ethylene copolymer resin used.
5 or less, and the content of comonomer to ethylene in the ethylene copolymer resin is 17 to 24% by weight.
As described above, the workability during film formation by the calendar method is good, and the curl resistance, foaming property, scratch resistance, flame retardancy, etc. when processed into a decorative sheet are further improved. An excellent decorative sheet can be obtained.

In the invention described in claim 3, the ethylene-acrylic copolymer resin of the foamable resin layer is ethylene-
The decorative sheet according to claim 2, which is a methyl methacrylate copolymer resin.

As the ethylene / acrylic copolymer resin of the foamable resin layer, as described above, ethylene-methyl methacrylate copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene-ethyl acrylate copolymer resin. , Ethylene-butyl methacrylate copolymer resin, ethylene-hexyl acrylate copolymer resin, ethylene-lauryl methacrylate copolymer resin, ethylene-stearyl acrylate copolymer resin and the like can be preferably used, but among them, ethylene -Methyl methacrylate copolymer resin has good processability, has appropriate flexibility and scratch resistance, and is excellent in overall performance as a foamable resin layer such as foamability and curl resistance. It can be used particularly preferably.

Therefore, by adopting the above-mentioned constitution, in addition to the function and effect of the invention described in claim 2, workability is further improved, and flexibility, scratch resistance, foaming property and curl resistance are improved. It is possible to obtain a decorative sheet having further excellent performance such as.

The invention according to claim 4 is the decorative sheet according to any one of claims 1 to 3, wherein a flame retardant is added to the foamable resin layer.

As the flame retardant, a known flame retardant can be used, but in the present invention, the foamable resin layer is formed so that harmful gas such as chlorine gas or hydrochloric acid gas is not generated when the decorative sheet is burned. The olefin copolymer resin as described above is used as the resin, and it is preferable to use the flame retardant other than the organic halogen compound such as the organic chlorine compound or the organic bromine compound.
Examples of such flame retardants include aluminum hydroxide, magnesium hydroxide, metal hydroxides such as calcium hydroxide, antimony trioxide, antimony pentoxide, antimony borate, antimony molybdate, zinc borate, and the like.
Inorganic oxides such as zinc stannate, titanium dioxide, boric acid, and triallyl phosphate, alkylallyl phosphate, alkyl phosphate, dimethyl phosphate, phosphorinate, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl. Phosphate ester or phosphorus compound such as phosphate, octyl diphenyl phosphate, tricresyl phosphate, cresyl phenyl phosphate, triphenyl phosphate, polyphosphonate, polyphosphate, aromatic polyphosphate, phosphonate type polyol, phosphate type polyol, etc. Polyol compound, other, silicone polymer, ferrocene, fumaric acid, maleic acid, triazine compound, melamine cyanu Over door, isocyanurate, urea,
A guanidine compound or the like can be used.

By adopting such a constitution, in addition to the function and effect of the invention described in any one of claims 1 to 3, it is possible to impart flame retardancy to the olefin-based copolymer resin of the foamable resin layer. Therefore, the flame retardancy of the decorative sheet can be improved.

The invention described in claim 5 is characterized in that a primer layer is provided between the foamable resin layer and the pattern ink layer, and a protective layer is provided on the pattern ink layer. The decorative sheet according to any one of 1 to 4.

The primer layer is provided to improve the adhesion of the pattern ink layer to the foamable resin layer, and is an emulsion or dispersion of, for example, an acrylic resin, an olefin resin, an ethylene-vinyl acetate copolymer resin or the like. It can be provided by a method of applying a coating material, and drying by heating to form a film. The protective layer provided on the pattern ink layer is provided to improve abrasion resistance, scratch resistance, etc. of the pattern ink layer, and also to improve heat resistance, and is not particularly limited. It can be provided by applying a coating solution of a transparent resin such as, and drying. In addition to the above, the protective layer may be provided by laminating a film, and in this case, the film softens and hinders foaming when the foamable resin layer is foamed in a heating furnace at 200 to 220 ° C., for example. Without doing
In addition, it is preferable to have a hardness that does not allow the foaming gas to flow out, and from this point, the melting point or softening point of the film is equal to or higher than that of the resin of the foamable resin layer or 10 to 20 ° C.
It is preferable that the degree is high. As the film for such a protective layer, polypropylene, polyethylene or copolymer resins thereof, for example, ethylene-methyl methacrylate copolymer resin, ethylene-ethyl methacrylate copolymer resin, ethylene-methyl acrylate copolymer resin, In addition to ethylene-ethyl acrylate copolymer resin, a film of polyester or copolymer polyester can be used.

By adopting such a constitution, in addition to the effect of the invention described in any one of claims 1 to 4, the adhesion of the pattern ink layer is further improved by the primer layer, and the protective layer is formed. Surface physical properties such as abrasion resistance, scratch resistance and heat resistance of the pattern ink layer can be further improved.

The invention according to claim 6 is the decorative sheet according to any one of claims 1 to 5, wherein the surface of the decorative sheet is embossed.

The above embossing may be mechanical embossing by heating or embossing, or chemical embossing. When chemical embossing is performed, for example, in a multicolored pattern ink layer, a foaming inhibitor such as trimellitic anhydride or maleic anhydride is added to at least one layer, or the pattern ink layer is Separately, one of the foam suppressing ink layers containing the foam suppressing agent in a desired pattern on the foamable resin layer, that is, under the pattern ink layer,
Alternatively, when the foamable resin layer of the decorative sheet is heated and foamed by providing it in the middle of the multicolored pattern ink layer, or on the pattern ink layer, etc. In the foamable resin layer, the foaming inhibitor penetrates into the interior to suppress foaming and becomes a recess, and in other portions, foaming of the foaming agent is not suppressed and the foaming resin layer is raised as it is, and the foamed resin layer is raised. The convex portions are formed, and the embossed pattern is formed by the patterned concave portions and convex portions.

Therefore, by adopting the above-mentioned constitution, in addition to the function and effect of the invention described in any one of claims 1 to 5, unevenness of a desired pattern or a pattern ink layer is formed on the surface of the decorative sheet. Since it is possible to easily provide the unevenness in synchronization with the above, it is possible to further improve the designability of the decorative sheet.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings. 1 and 2 are schematic cross-sectional views showing the structure of an embodiment of the decorative sheet of the present invention. In each drawing, (a) is a schematic cross-sectional view before foaming and (b) is after heat-foaming. It is a schematic cross section. However, the present invention is not limited to these drawings as long as the gist thereof is not exceeded.

FIG. 1A is a schematic sectional view showing the constitution of the decorative sheet 10 before heat-foaming, and FIG. 1B is a schematic sectional view showing the constitution of the decorative sheet 10 after heat-foaming.
The decorative sheet 10 shown in (a) of FIG. 1 has a foamable resin layer 2 provided on a base material (lining layer) 1 and a pattern ink layer (containing a foaming inhibitor) on which a foamable resin layer 2 is provided. 4 is provided, and the protective layer 5 is further provided thereon. This structure is a method in which a pattern ink layer (containing a foaming inhibitor) 4 containing a foaming inhibitor is provided in a pattern on a foamable resin layer 2 containing a foaming agent through a primer layer 3 to make up a makeup. The sheet 10 is configured to be chemically embossed in synchronization with the pattern ink layer 4 (containing the foaming inhibitor).

That is, the decorative sheet 10 having the structure shown in FIG. 1 (a) is passed through a heating furnace to heat and foam the expandable resin layer 2, so that the pattern ink layer (containing the foaming inhibitor) 4 is formed. In the provided portion, the foaming suppressant penetrates into the foamable resin layer 2 to suppress foaming of the foaming agent,
As shown in (b) of FIG. 1, the foam becomes low and a recess is formed. Then, in the portion where the pattern ink layer (containing the foaming inhibitor) 4 is not provided, since foaming is not suppressed, foaming is performed at a high magnification to form the foamed cell A, and the convex portion like the raised portion B is formed, By the concave portion and the convex portion, pattern-shaped irregularities are formed in synchronization with the pattern ink layer. still,
In the configuration of the decorative sheet 10, the primer layer 3 and the protective layer 5 are provided as necessary depending on the application of the decorative sheet 10, and may be removed if unnecessary.

In the constitution of the decorative sheet 10 described above, as the base material (backing layer) 1, paper, cloth or the like can be appropriately selected and used depending on the application of the decorative sheet. When using paper, it is preferable to use paper with flame retardancy,
Paper having a basis weight of about 50 to 120 g / m ² is used. When using cloth, in addition to ordinary woven cloth, non-woven cloth or woven cloth containing inorganic fibers such as glass fibers can be used.

The foamable resin layer 2 is, as described above,
Olefin-based copolymer resin is used as the main component resin
In particular, ethylene and the general formula “CH₂=
CR ₁COOR₂[In the formula, R₁Is H or CH₃And
R₂Is an alkyl group. ] Acrylic acid
Do not copolymerize ester or methacrylic acid ester
Ethylene / acrylic copolymer resin or a mixture of these
Compound resin or ethylene-vinyl acetate copolymer resin
Ethylene copolymer resin blended with fat is preferable,
In addition, as the ethylene / acrylic copolymer resin,
Lene-methyl methacrylate copolymer resin is particularly preferable,
In addition, ethylene in these ethylene-based copolymer resins
The comonomer content is 17-24% by weight.
Also, the MFR of these ethylene copolymer resins is
It is preferably 4.5 or less. And like this
At least foaming in the olefin copolymer resin as the main component
ADCA with a median diameter of less than 20 μm is added as an agent
In addition, the above-mentioned OBSH, TSH, DPT, etc.
Any foaming agent can be added in an appropriate amount. Also,
As an additive other than the foaming agent, if necessary, a foaming aid,
Foam cell conditioner, inorganic filler, flame retardant, lubricant, antistatic
Agent, light stabilizer, antioxidant, antibacterial agent, antifungal agent, pigment, firefly
A photowhitening agent and the like can be added as appropriate.

Such a foamable resin layer 2 can be formed into a desired thickness by a calendar method or an extrusion coating method and, at the same time, heat-bonded and laminated on the base material (backing layer) 1. Further, on the surface of the foamable resin layer 2, a corona discharge treatment for improving the adhesiveness of a layer (primer layer 3 or pattern ink layer 4 etc.) provided thereon,
It is preferable to perform an easy adhesion treatment such as ozone treatment.
The thickness of the foamable resin layer 2 can be appropriately set depending on the application of the decorative sheet, but the thickness before foaming is generally about 80 to 200 μm.

In this case, the primer layer 3 comprises a lower foamable resin layer 2 and an upper picture ink layer (containing a foaming inhibitor) 4
It is provided as necessary to improve the adhesiveness with, for example, an acrylic resin, an olefin resin, an ethylene-vinyl acetate copolymer emulsion or dispersion is applied, and the film is dried by heating. It can be provided by a method of forming. The pattern ink layer (containing a foaming inhibitor) 4 has good adhesiveness to the lower layer, light resistance,
Although it is necessary to have heat resistance, scratch resistance, stain resistance, etc., there is no particular limitation on the ink type or printing means used, and for example, using an ink with an acrylic resin as a binder, It can be easily provided by means of multicolor gravure printing, silk screen printing, flexo printing, or the like. As the foaming inhibitor contained in the pattern ink layer (containing the foaming inhibitor) 4, trimellitic acid anhydride, maleic acid anhydride or the like can be used as described above. In the case where the pattern ink layer is formed in multiple colors, such a foaming inhibitor may be contained in the ink layer in which it is desired to form concaves and convexes due to chemical embossing, regardless of one color or a plurality of colors. The content of the foaming inhibitor is appropriately contained in the ink solid content in the range of 10 to 40% by weight.

The protective layer 5 improves the abrasion resistance and scratch resistance of the surface of the decorative sheet 10 such as the pattern ink layer (containing the foaming inhibitor) 4 and the foaming resin layer 2, and also improves the heat resistance. It is provided for this purpose and is not particularly limited, but it can be provided, for example, by applying a coating liquid of a transparent resin such as acrylic resin and drying it. In addition to the slip agent and the antistatic agent, necessary additives can be appropriately added to the coating liquid for the protective layer. In addition, the protective layer 5
As described above, polypropylene, polyethylene or a copolymer resin thereof, for example, ethylene-methyl methacrylate copolymer resin, ethylene-ethyl methacrylate copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene. In addition to the ethyl acrylate copolymer resin, a film of polyester or copolymer polyester may be laminated and used.

The foamable resin layer 2 is formed by a calendering method at a temperature lower than the foaming temperature of the foaming agent, usually about 100 to 150 ° C. ) An unfoamed decorative sheet 10 as shown in
Is obtained. Then, this is passed through a heating and foaming furnace to 180
By heating to 220 ° C, the foaming agent contained in the foamable resin layer 2 is decomposed to generate gas, and as shown in Fig. 1B, the pattern ink layer (containing the foaming inhibitor).
The portion other than the portion provided with 4 foams at a high magnification to form a foamed cell A, and a convex portion is formed in a pattern as shown in the raised portion B, and a pattern ink layer (containing a foaming inhibitor) 4 In the portion where is provided, it is possible to manufacture the decorative sheet 10 in which the foaming inhibitor suppresses foaming, forms a recess with a low expansion ratio, and has an uneven pattern. The expansion ratio of the foamable resin layer 2 can be adjusted by the kind and addition amount of the foaming agent, the heating temperature and the like, and normally the thickness of the foamable resin layer 2 is expanded in the range of about 2 to 7 times. be able to.

The decorative sheet 20 shown in FIGS. 2 (a) and 2 (b) is the same as the decorative sheet 10 shown in FIG. 1 except that the chemical embossing method is changed. Instead of containing the agent in the pattern ink layer, a pattern-shaped foam suppressing ink layer 4b containing a foam suppressing agent is provided separately from the pattern ink layer. That is, the foamable resin layer 2 is formed on the base material (lining layer) 1.
Is provided, the primer layer 3 is provided thereon, the foaming suppression ink layer 4b is provided in a pattern, and the pattern ink layer 4a and the protective layer 5 are further provided thereon in this order.

Even in the case of adopting such a configuration, as shown in FIG. 2B, the unfoamed decorative sheet 20 shown in FIG. 2A is passed through a heating and foaming furnace to be foamed by heating. In addition, since the foaming inhibitor contained in the foaming suppressing ink layer 4b permeates the inside of the foamable resin layer 2 and suppresses the foaming, the portion where the foaming suppressing ink layer 4b is provided has low foaming and becomes a recess. And a portion where the bubbling suppression ink layer 4b is not formed foams at a high magnification to form a convex portion, and an uneven pattern is formed by both.

Although such a foaming suppression ink layer 4b is shown as having the same pattern under the pattern ink layer 4a in the figure, its position and pattern can be freely provided. For example, when the pattern ink layer 4a is multicolored, it may be provided not only on the lower side but also on the intermediate layer.
It can also be placed on top of a. Further, by providing the pattern of the bubbling suppression ink layer 4b, for example, in the pattern of the portion where the design ink layer 4a is not provided, the portion of the design ink layer 4a is foamed at a high magnification to form a convex portion, and the design ink layer is formed. It is also possible to suppress the foaming of the portion where 4a is not provided to form a concave portion. It is also possible to form the concave portion by providing the foam suppression ink layer 4b in a desired pattern irrespective of the pattern ink layer 4a and forming the concave portion and the other portion as the convex portion.

[0040]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. A decorative sheet used for wallpaper is prepared, and the structure shown in FIG. 1, that is, the base material (lining layer)
A decorative sheet having a structure in which 1, a foamable resin layer 2, a primer layer 3, a pattern ink layer (containing a foaming inhibitor) 4, and a protective layer 5 were laminated in this order was produced using the following materials. In the examples and comparative examples, the base material (backing layer) among the above-mentioned constitutions is used.
1, primer layer 3, pattern ink layer (containing foaming inhibitor)
4, a common material is used for the protective layer 5, only the composition of the resin composition used for the foamable resin layer 2 is changed to the composition shown in Table 1, and Examples 1 to 5 and Comparative Example 1 are used. No. 2 decorative sheet was produced. However, also in the formulation shown in Table 1, it is the median diameter of ADCA mainly used as the foaming agent among the additives that is changed.

The foamable resin layer 2 is formed by forming a resin composition having the composition shown in Table 1 by a calendering method at a roll temperature of 150 ° C. to a thickness of 130 μm.
It is laminated on the base material (backing layer) 1 by heat bonding. The foaming of the expandable resin layer 2 is carried out by producing each unfoamed decorative sheet and then passing it through a heating foaming furnace under the conditions of 220 ° C. for about 30 seconds.

The base material (backing layer) 1 has a basis weight of 70 g /
A m ² semi-flame retardant paper was used. For the primer layer 3, an emulsion of an ethylene-vinyl acetate copolymer resin was used, which was applied by a reverse roll coater to a dry thickness of 2 μm and dried by heating to form a film. The pattern ink layer (containing a foaming inhibitor) 4 is a lattice pattern formed by gravure printing by adding trimellitic anhydride as a foaming inhibitor to the acrylic binder ink so that the content in the solid content is 30% by weight. Was formed by printing (1 color). The protective layer was formed by printing a transparent acrylic resin solution (with a slip agent added) on the entire surface by gravure printing so that the thickness when dried was 3 μm. For the expandable resin layer 2, the decorative sheets of Examples 1 to 5 and Comparative Examples 1 and 2 were prepared using the resin compositions having the formulations shown in Table 1 below.

[0043]

[Table 1]

In Table 1, resin / EMMA-1, EM
MA-2 is an ethylene-methyl methacrylate copolymer resin, and has a different comonomer content and MFR. In addition, the inorganic fillers aluminum hydroxide and titanium oxide are white colorants and at the same time have an action as a flame retardant. The zinc compound as the foam cell regulator improves the foamability of the foamable resin layer, the uniformity of foaming, and the like. In addition, the foaming aid ZnO (zinc white)
In the case of using, the foaming temperature of the foaming agent, that is, the decomposition start temperature is lowered to improve the foamability of the foamable resin layer,
By lowering the foaming temperature, heat deterioration of the material of the decorative sheet can be prevented, and the quality and performance of the decorative sheet can be improved. The silicone-based flame retardant not only imparts flame retardancy to the olefin-based copolymer resin, but also adjusts the melt tension of the resin and densifies the foamed cells. And
Zinc stearate as a lubricant has a function as a foaming aid as well as a lubricant.

With respect to the decorative sheets of Examples 1 to 5 and Comparative Examples 1 and 2 produced as described above, the following items were measured and performances were evaluated, and the results are summarized in Table 2. (1) The content of the comonomer (MMA) in the olefin-based copolymer resin of the foamable resin layer is shown by weight%. (2) MFR of olefin-based copolymer resin of foamable resin layer
Was measured and the numerical value was shown. Unit [g / 10 min] (3) Foam suppression effect: The foam suppressing effect of the foamable resin layer by the foam suppressing agent added to the pattern ink layer is judged by the uneven shape formed, and those having an excellent foam suppressing effect are ○. The medium grade was marked with Δ and the inferior grade was marked with x. (4) Whiteness of the expandable resin layer after foaming: ⊚ for excellent whiteness, ◯ for good whiteness, Δ for slightly yellowish color,
Those that were yellowish and inferior in whiteness were shown as x. (5) Surface smoothness of the decorative sheet after foaming (smoothness of the surface): ○ if the surface of the decorative sheet has no crushing and has excellent surface smoothness, ○, if there are slight irregularities but is not conspicuous, surface is Those with poor smoothness are shown as x. (6) Scratch resistance of the surface of the decorative sheet after foaming: R scratched at the same position on the surface of the decorative sheet 30 times with a nail, ○: scratches were slightly scratched but were inconspicuous, and scratches were marked. Those with a lot of marks are shown as x.

[0046]

[Table 2]

Although not shown in Table 2, in the decorative sheet of the present invention, an olefin copolymer resin is used as the resin of the foamable resin layer and a polyvinyl chloride resin is not used, In addition, since compounds containing halogen elements such as chlorine and bromine are not used for other constituent materials such as flame retardants, no harmful gas such as hydrochloric acid gas or chlorine gas is generated even when the decorative sheet is burned. It was also excellent in safety.

As is clear from the above results, Example 1
In the decorative sheets of Nos. 5 to 5, ethylene-methyl methacrylate (EMM) was added to the olefin copolymer resin of the foamable resin layer.
A) A mixed resin of a copolymer resin is used, which contains ADCA having a median diameter of less than 20 μm as a foaming agent, the mixed resin has an MFR of 4.5 or less, and a comonomer (MMA) in the mixed resin. A resin composition containing a content in the range of 17 to 24% by weight and, as shown in Table 1 as an additive, an inorganic filler, a flame retardant, a foam cell regulator, and a lubricant as appropriate. Since the layer is formed, it has excellent processability in calender molding, curl resistance, foaming property, and flame retardancy, and also has the foaming suppressing effect described in (3) to (6) above and after foaming of the foamable resin layer. The whiteness, the surface smoothness of the decorative sheet after foaming (smoothness of the surface), and the scratch resistance of the surface of the decorative sheet after foaming were substantially good.

On the other hand, in the decorative sheets of Comparative Examples 1 and 2, since ADCA having a median diameter of 20 μm or more was used as the foaming agent added to the foamable resin layer, the foamable resin layer after foaming had In addition to being yellowish and inferior in whiteness, it was also inferior in surface smoothness (smoothness of the surface), which was not preferable in terms of inferior printing effect and appearance.

[0050]

As described above in detail, according to the present invention, interior materials for buildings such as wallpaper, floor materials, and ceiling materials, surface coating materials for other furniture, home appliances, leather, book covers, etc. A decorative sheet that can be used for a wide range of applications such as surface materials, in which a foaming resin layer made of a resin composition obtained by adding a foaming agent to an olefin-based copolymer resin and other necessary additives is laminated on the intermediate layer, etc. It has excellent processability such as calender molding, foamability, curl resistance, and flame retardancy, and also suppresses foaming by a foaming inhibitor during chemical embossing, whiteness of foamable resin layer after foaming, and decorative sheet after foaming. The compound has excellent surface smoothness (smoothness of surface), good surface scratch resistance, tactile sensation, and flexibility, and its constituent materials include polyvinyl chloride resin and halogen elements such as chlorine and bromine. Does not use, in without having to generate harmful gases such as hydrochloric acid gas or chlorine gas even when burned in a fire or after use incineration, the performance and printing,
In addition to the design by embossing, it is effective in providing a decorative sheet with excellent safety and environmental suitability with high productivity.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of an embodiment of a decorative sheet of the present invention, (a) is a schematic cross-sectional view before foaming, (b).
[FIG. 4] is a schematic cross-sectional view after heat-foaming.

FIG. 2 is a schematic cross-sectional view showing the structure of another embodiment of the decorative sheet of the present invention, (a) is a schematic cross-sectional view before foaming,
(B) is a schematic cross-sectional view after foaming by heating.

[Explanation of symbols]

1 Base material (lining layer) 2 Foamable resin layer 3 Primer layer 4 Design ink layer (containing foam suppressor) 4a Design ink layer 4b Foam suppression ink layer 5 protective layer A foam cell B ridge 10, 20 Decorative sheet

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuyuki Ono             1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo             Dai Nippon Printing Co., Ltd. F-term (reference) 4F100 AH02B AH02H AH03B AH03H                       AK01B AK68B AK71B AL05B                       AT00A BA02 CA01B CA08B                       DG10A DJ01B GB08 GB48                       GB81 HB21B HB31B JA06B                       JK15 YY00B YY00H

Claims (6)

[Claims] 1. A decorative sheet obtained by heat-foaming a laminate in which at least a foamable resin layer and a pattern ink layer are laminated on a substrate (backing layer), wherein the foamable resin layer is an olefin-based copolymer. A decorative sheet comprising a resin composition as a main component, which is formed by adding at least azodicarbonamide as a foaming agent thereto, and a median diameter of the azodicarbonamide is less than 20 μm. 2. The olefin-based copolymer resin comprises ethylene and a general formula “CH ₂ ═CR ₁ COOR ₂ ” [wherein, R ₁ is H or CH ₃ and R ₂ is an alkyl group. ] An ethylene / acrylic copolymer resin obtained by copolymerizing an acrylic ester or a methacrylic ester represented by: or a mixed resin thereof, or an ethylene-
An ethylene-based copolymer resin blended with a vinyl acetate copolymer resin, wherein the ethylene-based copolymer resin has an MFR of 4.5 or less, and the ethylene-based copolymer resin has a comonomer content of 17 to 24 relative to ethylene. The decorative sheet according to claim 1, wherein the decorative sheet is in weight%. 3. The ethylene / acrylic copolymer resin,
The decorative sheet according to claim 2, which is an ethylene-methyl methacrylate copolymer resin. 4. The decorative sheet according to claim 1, wherein a flame retardant is added to the foamable resin layer. 5. A primer layer is provided between the foamable resin layer and the pattern ink layer, and a protective layer is provided on the pattern ink layer. The described decorative sheet. 6. The decorative sheet according to claim 1, wherein the surface of the decorative sheet is embossed.