JP4450845B2 - Decorative sheet - Google Patents

Description

  The present invention relates to a decorative sheet, and more particularly to a decorative sheet suitable for use in an interior of a building, a surface makeup of a fitting, a vehicle interior, and the like.

Conventionally, a decorative sheet (Patent Document 1, Patent Document 2, etc.) that uses a polyvinyl chloride film and is decorated by printing, embossing or the like has been used as a decorative sheet used for the above-mentioned purposes. In recent years, as an alternative,
(I) A decorative sheet using a polyolefin film such as polyethylene or polypropylene has been proposed (see Patent Document 3).
(II) Further, (I) as an improved specification, a polyolefin resin in which a polar functional group is graft-polymerized and an olefin elastomer mixed (Patent Document 4, Patent Document 5, etc.), or a polyolefin resin A material in which a polyurethane resin is mixed using a compatibilizer (Patent Document 6, etc.) has also been proposed.

Japanese Patent Publication No. 28-5036 Japanese Examined Patent Publication No. 58-14312 JP 54-62255 A JP-A-6-210808 Japanese National Patent Publication No. 4-504384 JP-A-7-26038

  However, the proposed decorative sheet using the polyolefin resin sheet as described above is not always satisfactory. That is, a function as shown in the following (1) to (10) is usually required for a surface decorative sheet used for interior / exterior of a building, surface cosmetics such as joinery / furniture, and vehicle interiors.

(1) Thermoformability comparable to polyvinyl chloride. In particular, the change in elongation at constant load with temperature change should be a gradual and continuous change that is almost the same as polyvinyl chloride. In addition, there should be no deterioration of material mechanical properties such as strength reduction with heating → cooling.
(2) Creep deformation resistance. The exterior material and interior material are often subjected to a constant load by joinery or furniture for a long time, and when creep deformation occurs, the load portion is turned over or peeled off. Therefore, it is required that the material does not cause creep deformation as much as possible.
(3) Cold bending strength. When the bending process such as the V-cut process is performed at the time of cold, when the stress relaxation is insufficient, whitening, cracks, breakage and the like are likely to occur in the bent part.
(4) Organic solvent resistance. The decorative sheet is prevented from swelling and deforming due to the solvent in the adhesive that bonds the decorative sheet and the adherend. The same applies to the case where a multi-layered decorative sheet is obtained.
(5) Elongation at break and impact strength. This characteristic is required in order to prevent cracking of the bent portion during V-cut processing.
(6) It has an appropriate bending elastic modulus. It is required for the followability of the decorative sheet at the bent portion to be sufficient.
(7) Good transparency.
(8) Even if heating and cooling accompanying embossing or the like are applied, whitening and turbidity due to recrystallization do not occur.
(9) Easy adhesion. In particular, in the case of a base sheet, it is desired that it can be easily bonded to various adherends using a wide range of adhesives when using a decorative sheet.
(10) Excellent weather resistance.

  The decorative sheet having the above-mentioned specification (I) is difficult to industrially mass-produce, and the polyolefin resin has a high degree of crystallinity, and therefore, as shown by the curve b in FIG. Compared to resins, the change in physical properties before and after the melting point is steep, and the processable condition range is narrower than that of a conventional general-purpose polyvinyl chloride sheet (curve a in FIG. 1). In particular, the conditions (1) and (5) to (10) could not be sufficiently satisfied. The specifications of (II) improved the conditions of (1), (5), (6) and improved thermoformability, embossability, etc. by mixing olefin-based elastomer, but transparent The property, weather resistance, and heat resistance were insufficient.

  The object of the present invention is to eliminate the above-mentioned disadvantages of conventional decorative sheets using olefinic resins. Specifically, cosmetics using polyvinyl chloride resin while using olefinic resins are used. An object of the present invention is to provide a decorative sheet having the same thermoformability, weather resistance and transparency as the sheet.

  1 is a graph showing the relationship between temperature and elongation when various sheets are heated under a constant load (under a constant tensile stress). Curve a is a semi-rigid vinyl chloride sheet, and curve b is a crystal. The curve c shows the case of the laminated sheet according to the present invention to be described later.

  The present inventors have conducted a number of experiments and research to solve the above-mentioned problems, so that the decorative sheet is not a single-layer sheet, but at least a base sheet and a two-layer structure of a surface sheet laminated thereon, It has been found that an olefinic resin decorative sheet having high practicality can be obtained by sharing the various conditions required for the decorative sheet in each sheet, and thus the present invention has been made.

  And let the base sheet mainly bear (1) to (6) and (9) in the above conditions, and the top sheet laminated on the surface of the base sheet has the conditions (1) to (8) and (10) was mainly carried. On the basis of the premise, polypropylene (PP) was selected as the polyolefin that is the base of the base sheet, because it has excellent basic performance. Table 1 shows the degree of satisfaction of the conditions (1) to (10) required for the decorative sheet of polypropylene.

* 1: Steep change in sheet elongation before and after the melting point. Also, at the time of embossing, the elongation decreases due to crystallization improvement by cooling.
* 2: Yield point stress is high.
* 3: The flexural modulus is too high.
* 4: The tendency of cloudiness due to fine crystal grains.

  Therefore, an elastomer was added to inhibit crystallization and absorb and relax stress during molding. As a result, each condition changed as shown in Table 2.

  As a result, the conditions (1), (5), and (6) were satisfied, but the creep resistance of (2) was somewhat lowered. Therefore, inorganic particulate extender pigment was further added. As a result, each condition changed as shown in Table 3.

  Thereby, it was confirmed that the creep deformation resistance was also improved, and that satisfying the performances (1) to (6) and (9) as the base sheet was obtained. Next, first, an isotactic polypropylene sheet having high transparency and excellent weather resistance was selected as a surface sheet to be superimposed on the surface of the base material sheet. About this sheet | seat, the satisfaction degree of the conditions of said (1)-(10) was investigated. Table 4 shows the degree.

* 5: Due to the high crystallinity of isotactic polypropylene.
* 6: White turbidity occurred due to recrystallization.
* 7: In order to improve weather resistance while maintaining transparency, even when a highly transparent organic UV absorber is added, the compatibility with the UV absorber is poor, and the UV absorber bleeds on the surface over time. (Exudation) to reduce the effect.

  Therefore, a mixed resin of isotactic polypropylene and atactic polypropylene having a low crystallization rate was used, and the degree of satisfaction of the conditions (1) to (10) was examined by reducing the crystallinity. Table 5 shows the degree.

  As shown in Table 5, the degree of satisfaction of (1) and (3) decreased somewhat by using a mixed resin of isotactic polypropylene + atactic polypropylene, but by laminating with a base sheet Reinforcement for that amount has been received, and the stress at the time of bending is partly dispersed in the base sheet layer, so that whitening and cracks are not noticeable in the laminated sheet state. In addition, although the easy adhesion of (9) is not completely satisfied, in the case of a face sheet, an appropriate adhesive can be selected at the time of manufacturing the decorative sheet, or adhesion to the base sheet can be achieved by using heat fusion. It was sufficient if possible, and it was confirmed that there was no problem as a finished decorative sheet.

  The present invention is based on the above experimental results. Basically, the decorative sheet according to the present invention is formed on a colored film as a base sheet comprising main ingredients of polypropylene, an elastomer, a colorant, and an inorganic filler. As a surface sheet, a colorless or colored transparent soft polypropylene resin film in which molecules consisting of a mixed system of isotactic polypropylene and atactic polypropylene have a composite three-dimensional structure is laminated, and a base sheet or surface sheet as required It is characterized by patterning either or both of these.

  The polypropylene in the present invention is preferably an isotactic polypropylene and a polymer having a high degree of crystallinity and a small number of branched structures.

  As the elastomer in the present invention, diene rubber, hydrogenated diene rubber, olefin elastomer and the like are used. Hydrogenated diene rubber is made by adding a hydrogen atom to at least part of the double bond of the diene rubber molecule, and suppresses the crystallization of polyolefin resin (in the present invention, polypropylene) to increase flexibility. Let Examples of the diene rubber include isoprene rubber, budadiene rubber, butyl rubber, propylene / budadiene rubber, acrylonitrile / budadiene rubber, acrylonitrile / isoprene rubber, and styrene butadiene rubber. The olefin elastomer is an elastic copolymer to which at least one polyene that can be copolymerized with two or three or more olefins is added. As the olefin, ethylene, propylene, α-olefin, or the like is used. 1,4 hexadiene, cyclic diene, norbornene and the like are used. Preferred examples of the olefin copolymer rubber include elastic copolymers containing olefin as a main component such as ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene rubber, and ethylene-butadiene copolymer rubber. These elastomers are appropriately crosslinked as required. As the crosslinking agent, known substances such as sulfur, aliphatic organic peroxides and aromatic organic peroxides are used.

  The addition amount of the elastomer is 10 to 60% by weight, preferably about 30% by weight. If the elastomer is lower than 10% by weight, the change in elongation at a constant load becomes too steep, and the elongation at break and impact resistance decrease. If the elastomer is higher than 60% by weight, transparency and weather resistance are deteriorated. In addition, the creep resistance is reduced. As the inorganic filler in the present invention, powder having an average particle diameter of about 0.1 to 10 μm such as calcium carbonate, barium sulfate, alumina, silica, clay, talc and the like is used. As addition amount, it is about 1 to 60 weight%, More preferably, it is 5 to 30 weight%. When the content is less than 1% by weight, creep deformation resistance and easy adhesion are deteriorated. When the content is more than 60% by weight, elongation at break and impact resistance are deteriorated.

  The colorant in the present invention is for giving the base sheet the color necessary as a decorative sheet, such as titanium white, zinc white, dial, vermilion, ultramarine, cobalt blue, chrome lead, titanium yellow, carbon black, etc. Inorganic pigments, isoindolinone, Hansa Yellow A, quinacridone, permanent red 4R, organic pigments or dyes such as phthalocyanine blue, metal pigments made of foil powder such as aluminum and brass, titanium dioxide-coated mica, basic zinc carbonate, etc. A pearlescent pigment made of foil powder is used. The coloring can be either transparent coloring or opaque (hiding) coloring, but in general, opaque coloring is preferable in order to hide the adherend.

  Furthermore, a heat stabilizer, a flame retardant, a radical scavenger, etc. are added as needed. The heat stabilizer is a known one such as phenol-based, sulfite-based, phenylalkane-based, phosphite-based, or amine-based, and is used for further improving the prevention of deterioration such as thermal discoloration during heat processing. As the flame retardant, powders such as aluminum hydroxide and magnesium hydroxide are used, and these are added when it is necessary to impart flame retardancy.

  A blend of these materials is formed into a film by a conventional method such as a calendering method to obtain an opaque colored base sheet. As described above, the obtained base sheet satisfies the conditions (1) to (6) and (9) required for the base sheet of the decorative sheet. The thickness of the base sheet is about 50 to 200 μm, preferably about 100 μm.

  The surface of the base sheet is preferably subjected to easy adhesion treatment such as application of an easy adhesion layer, corona discharge treatment, plasma treatment, ozone treatment, and the like. Acrylic resin, vinyl chloride-vinyl acetate copolymer, polyester resin, urethane resin, chlorinated polypropylene, and chlorinated polyethylene are used as the easy adhesion layer (also referred to as primer layer or anchor layer). Resin is desirable.

  Acrylic resins include poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) propyl acrylate, poly (meth) butyl acrylate, methyl (meth) acrylate / butyl (meth) acrylate Copolymer, (Meth) acrylic such as ethyl (meth) acrylate / butyl (meth) acrylate copolymer, ethylene / methyl (meth) acrylate copolymer, styrene / methyl (meth) acrylate copolymer An acrylic resin made of a homopolymer or a copolymer containing an acid ester (here, (meth) acryl means acryl or methacryl) or the like is used.

  The urethane resin (polyurethane) is a polyurethane having a polyol (polyhydric alcohol) as a main ingredient and an isocyanate as a crosslinking agent (curing agent). As the polyol, one having two or more hydroxyl groups in the molecule, for example, polyethylene glycol, polypropylene glycol, acrylic polyol, polyester polyol, polyether polyol and the like are used.

  As the isocyanate, a polyvalent isocyanate having two or more isocyanate groups in the molecule is used. For example, aromatic isocyanate such as 2-4 tolylene diisocyanate, xylene diisocyanate, 4-4 diphenylmethane diisocyanate, or aliphatic (or alicyclic) such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate ) Isocyanates are used. Alternatively, adducts or multimers of these isocyanates can be used. Examples include adducts of tolylene diisocyanate and trimers of tolylene diisocyanate.

  A pattern layer is formed on the surface subjected to the easy adhesion treatment as necessary. The pattern layer is formed on one or both of the base sheet and the surface sheet described in detail later. FIG. 2A shows an example in which an easy-adhesion layer is formed, and an easy-adhesion layer 4 is provided between the surface sheet 2 laminated on the base sheet 1 and the pattern layer 3. As shown in FIG. 2D, the easy-adhesion layer 4 may be provided on the side where the base sheet 1 faces the adherend 31. As pattern processing, printing of pattern 3 as shown in FIG. 2 (A), embossing (heating press) as shown in FIG. 2 (B), uneven pattern shaping 5 by hairline processing, etc. Furthermore, the colored ink 6 can be filled in the concave portions of the concave-convex pattern 5 by a known wiping method.

  As the pattern printing, a pattern is formed with ink (or paint) using a known printing method such as gravure printing, offset printing, silk screen printing, transfer printing from a transfer sheet. Examples of the pattern include a grain pattern, a stone pattern, a texture pattern, a leather pattern, a geometric figure, a character, a symbol, or a solid surface.

  Ink (or) paint, binder, chlorinated polyolefin resin such as chlorinated polyethylene, chlorinated polypropylene, polyester resin, urethane resin, acrylic resin, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, cellulose resin , Etc., or a mixture of one or more. To this is used a known pigment added as listed above. When printing directly on the base sheet, chlorinated polyolefin, urethane resin, etc. are preferable as the binder from the viewpoint of adhesiveness. However, if an easy adhesion primer is appropriately selected to form a layer, other binders are used. Also give sufficient adhesion.

  Embossing is a process in which a base sheet is heated and softened, pressed and shaped with an embossing plate, and fixed by cooling. A known single wafer or a rotary embossing machine is used. Examples of the uneven shape include a wood grain plate conduit groove, a stone plate surface unevenness (such as a granite cleaved surface), a cloth surface texture, a satin texture, a sand texture, a hairline, and a single line groove. The colored ink can be the same as described above. However, the thing which uses a two-component curable urethane resin as a binder is preferable at the point of abrasion resistance.

  The metal thin film is formed by a method such as vacuum deposition or sputtering using a metal such as aluminum, chromium, gold, silver, or copper. Or a combination of these may be used. The metal thin film may be provided on the entire surface or partially in a pattern.

  In the decorative sheet according to the present invention, the surface of the base sheet that has been subjected to a pattern treatment as necessary as described above is a colorless or colorless molecule in which a molecule composed of a mixed system of isotactic polypropylene and atactic polypropylene has a composite three-dimensional structure. A colored transparent soft polypropylene resin film is laminated as a top sheet.

  Polypropylene having a compound steric structure in which a molecule composed of a mixture of isotactic polypropylene and atactic polypropylene has a complex steric structure is preferably (A) (i) magnesium, titanium, halogen atom, and the like described in JP-B-6-23278. A solid catalyst component containing an electron donor as an essential component, (b) an organoaluminum compound, and (c) a general formula

（式中のＲ^１は炭素数１〜２０のアルキル基、Ｒ^２は炭素数１〜１０の炭化水素基、水酸基又はニトロ基、ｍは１〜６の整数、ｎは０又は１〜（６−ｍ）の整数である）で表されるアルコキシ基含有芳香族化合物の組み合わせからなる触媒の存在下、プロピレンを重合させることにより得られる、数平均分子量（Ｍｎ）が２５０００以上、かつ、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）との比Ｍｗ／Ｍｎが７以下の沸騰ヘプタン可溶性ポリプロピレン（アタクチックポリプロピレン）１０〜９０重量％と、（Ｂ）メルトインデックスが０．１〜４ｇ／１０分の沸騰ヘプタン不溶性ポリプロピレン（アイソタクチックポリプロピレン）９０〜１０重量％とからなる軟質ポリプロピレン系樹脂組成物である。

(In the formula, R ¹ is an alkyl group having 1 to 20 carbon atoms, R ² is a hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group or a nitro group, m is an integer of 1 to 6, and n is 0 or 1 to (6 A number average molecular weight (Mn) of 25,000 or more obtained by polymerizing propylene in the presence of a catalyst comprising a combination of alkoxy group-containing aromatic compounds represented by -m), and a weight average Ratio of molecular weight (Mw) to number average molecular weight (Mn) Mw / Mn is 10 to 90% by weight of boiling heptane soluble polypropylene (atactic polypropylene) having 7 or less, and (B) melt index is 0.1 to 4 g / 10 A soft polypropylene resin composition comprising 90 to 10% by weight of boiling water heptane-insoluble polypropylene (isotactic polypropylene).

In the present invention, the flexible polypropylene resin composition which is a surface sheet has a breaking elongation (T _B ) of 400% or more, preferably 500 to 700%, and a residual elongation after 100% elongation (PS ₁₀₀ ) of 80% or less. , preferably 50% to 75%, and at break stress _{(M B)} and at yield stress _{(M Y)} ratio _M B / _{M Y} with 1.0 or more, preferably in the range of 1.5 to 3.5 is there. If these mechanical properties deviate from the above range, the object of the present invention cannot be sufficiently achieved.

In the soft polypropylene-based resin composition, the component (A) is an atactic polypropylene that is soluble in boiling heptane and has a number average molecular weight (Mn) of 25,000 or more, preferably in the range of 30000 to 60000, and weight. The ratio Mw / Mn between the average molecular weight (Mw) and the number average molecular weight (Mn) is 7 or less, preferably 2-6. When the Mn is less than 25000 or the Mw / Mn is more than 7, the effect of contributing to the mechanical properties of the atactic polypropylene in the obtained resin is not sufficiently exhibited, and the stress at break (M _B) and or the ratio _M B / _{M Y} becomes less than 1.0 and at yield stress _{(M Y),} the residual elongation after 100 elongation (PS ₁₀₀₎ is or exceeds 80%, the object of the present invention Cannot be reached.

  The atactic polypropylene as the component (A) may be a propylene homopolymer, comprising propylene alone and other α-olefin units having 2 to 30 carbon atoms, preferably 30 wt% or less, preferably 30 wt% or less. The propylene copolymer contained may be sufficient. Moreover, this atactic polypropylene may be used 1 type, and may be used in combination of 2 or more type.

  Such an atactic polypropylene of component (A) can be produced by a known method (Japanese Patent Publication No. 6-23278). Specifically, (b) a solid catalyst component containing magnesium, titanium, a halogen atom and an electron donor as essential components, (b) an organoaluminum compound, and (c) a general formula

（式中のＲ¹は炭素数１〜２０のアルキル基、Ｒ^２は炭素数１〜１０の炭化水素基、水酸基又はニトロ基、ｍは１〜６の整数、ｎは０又は１〜（６−ｍ）の整数である）で表されるアルコキシ基含有芳香族化合物の組み合わせからなる触媒の存在下、プロピレンを重合させることにより、所望のアタクチックポリプロピレンを得ることができる。

(In the formula, R ¹ is an alkyl group having 1 to 20 carbon atoms, R ² is a hydrocarbon group having 1 to 10 carbon atoms, a hydroxyl group or a nitro group, m is an integer of 1 to 6, and n is 0 or 1 to (6 A desired atactic polypropylene can be obtained by polymerizing propylene in the presence of a catalyst comprising a combination of alkoxy group-containing aromatic compounds represented by -m).

  In the soft polypropylene resin composition, as the component (B), a crystalline isotactic polypropylene insoluble in boiling heptane having a melt index (MI) of 0.1 to 4 g / 10 min is preferably used. If the melt index is less than 0.1 g / 10 min, the melt characteristics are low and sheet forming becomes difficult. If it exceeds 4 g / 10 minutes, the mechanical strength becomes insufficient and V-cut processing cannot be performed satisfactorily.

  The isotactic polypropylene as the component (B) may be a polypropylene homopolymer having isotactic stereoregularity, or a copolymer of propylene having other stereoregularity and another α-olefin. It may be. Other α-olefins used in this copolymer are preferably those having 2 to 8 carbon atoms, such as ethylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, etc. Among these, ethylene and butene-1 are preferable. Moreover, as a copolymer, the block copolymer and random copolymer which contain the said other (alpha) -olefin unit normally 40 weight% or less, Preferably 30 weight% or less are used.

  Preferred examples of the (B) component isotactic polypropylene include a propylene homopolymer, and a random copolymer of propylene and ethylene containing 1 to 30% by weight, preferably 3 to 25% by weight of ethylene units, or A block copolymer is mentioned. There is no restriction | limiting in particular about the manufacturing method of such an isotactic polypropylene, Arbitrary methods can be selected and used from the methods conventionally used for manufacture of crystalline polypropylene.

In the soft polypropylene resin composition used in the present invention, one type of isotactic polypropylene as the component (B) may be used, or two or more types may be combined. The atactic polypropylene as the component (A) and the isotactic polypropylene as the component (B) have a content of the component (A) of 10 to 90% by weight, preferably 25 to 80% by weight. Is used in a proportion such that the content of is 90 to 10% by weight, preferably 75 to 20% by weight. When the content of the component (A) is less than 10% by weight, the stress at yield (M _Y ) of the resin becomes too large, and the ratio M _B between the stress at break (M _B ) and the stress at yield (M _Y ) M _B When / _MY is less than 1.0 and the residual elongation after 100% elongation (PS ₁₀₀ ) is also greater than 80%, the object of the present invention cannot be achieved. Meanwhile at break stress and exceeds 90 wt% (M _B) is too small, the M _{B /} M _Y is less than 1.0, and decreased mechanical strength, can not be achieved an object of the present invention. Moreover, the Young's modulus of the soft polypropylene obtained becomes high by making the ratio of (B) component high. A particularly preferred ratio of the component (A) and the component (B) is 1: 1.

  In order to reinforce the function required as the surface layer of the decorative sheet, the flexible polypropylene resin composition may be optionally added with various additives, reinforcing materials, fillers, for example, an ultraviolet absorber, a light stabilizer, and a heat resistant stability. Agents, antioxidants, antistatic agents, flame retardants and the like are added. The flame retardant may be the same as that of the base sheet.

  In order to improve the weather resistance (light) property, it is preferable to add an organic or inorganic ultraviolet absorber in the surface sheet. Among these ultraviolet absorbers, an organic ultraviolet absorber having excellent transparency is preferable. As this type of ultraviolet absorber, an organic compound having a hydroxyl group (OH group) in the molecule is used. The reason for selecting one having a hydroxyl group in the molecule is to stop bleeding of the ultraviolet absorber by a top coat film of a resin having an isocyanate group described later.

  Examples of such an ultraviolet absorber include 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3′-). tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3′-tert-amyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2 ′ 2 'such as -hydroxy-3'-isobutyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-isobutyl-5'-propylphenyl) -5-chlorobenzotriazole -Hydroxyphenyl-5-chlorobenzotriazole ultraviolet absorbers, 2- (2'-hydroxy-3 ', 5'-di-tert-butyl Benzotriazole ultraviolet absorbers such as 2′-hydroxyphenylbenzotriazole ultraviolet absorbers such as 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, and 2,2′-dihydroxy 2,2′-dihydroxybenzophenone ultraviolet absorbers such as -4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2′-dihydroxy-4,4′-tetrahydroxybenzophenone Benzophenone ultraviolet absorbers such as 2-hydroxybenzophenone ultraviolet absorbers such as 2-hydroxy-4-methoxybenzophenone and 2,4-dihydroxybenzophenone, phenyl salicylate, 4-t-butyl-phenyl-salicylate, etc. Salicylic acid esthetic System ultraviolet absorber is used. In addition, a reactive ultraviolet absorber in which an acryloyl group or a methacryloyl group is introduced into the benzotriazole skeleton is also used. Or when high transparency is not requested | required, an inorganic type ultraviolet absorber can also be added. As the inorganic ultraviolet absorber, titanium oxide, cerium oxide, iron oxide or the like having a particle size of 0.2 μm or less is used. In addition, the addition amount of these ultraviolet absorbers is about 0.1 to 5 weight% normally.

  In order to further prevent deterioration due to ultraviolet rays and improve weather resistance, it is preferable to add a radical scavenger as another light stabilizer. As this radical scavenger, bis- (2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis- (N-methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate In addition, for example, hindered amine radical scavengers such as compounds disclosed in Japanese Patent Publication No. 4-82625, piperidyl radical scavengers, and the like are used. The addition amount of these radical scavengers is usually about 0.1 to 5% by weight. In addition, when adding a light stabilizer comprising a hindered amine radical scavenger to the surface sheet, the layers such as an ink layer and an adhesive layer adjacent to the surface sheet are in a molecule such as a urethane resin, a polyester resin, and a polyamide resin. If a resin containing no chlorine atom is used, it is favorable in terms of improving weather resistance. If resins containing chlorine atoms in the molecule such as vinyl chloride / vinyl acetate copolymer and chlorinated polyolefin are used, hydrogen chloride is generated from these resins by the action of ultraviolet rays or heat, which is hindered amine. The weather resistance is not sufficiently improved because it reacts with the radical scavenger and deactivates or inhibits its action.

  When the ultraviolet absorbent having a hydroxyl group in the molecule is added to the surface sheet, preferably, a top coat film made of a resin having an isocyanate group in the molecule is formed on the surface side of the surface sheet. As the resin having an isocyanate group in the molecule, a two-component curable urethane resin or a one-component curable urethane resin is used. As the two-component curable urethane resin, a mixture of polyol and isocyanate similar to those described above as the resin system of the easy-adhesion layer is used.

  In addition, as a preferable aspect in the case of using a two-component curable urethane resin, the number (mole number) of isocyanate groups (NCO groups) in isocyanate is more than the number (reaction equivalent) of hydroxyl groups (OH groups) of the polyol to be reacted therewith There is an embodiment in which a large number of unreacted isocyanate groups remain reliably even after the polyol and isocyanate are reacted. In this case, the NCO group / OH group ratio is about 1.4 at maximum.

  The one-component moisture-curing urethane resin is a composition containing a prepolymer having an isocyanate group at the molecular end as an essential component. The prepolymer is usually a polyisocyanate prepolymer having one or more isocyanate groups at both molecular ends, and is in the state of a solid thermoplastic resin at room temperature. The isocyanate groups react with moisture in the air to cause a chain extension reaction. As a result, a reaction product having a urea bond in the molecular chain is generated, and the isocyanate group at the molecular end further reacts with this urea bond. , Biuret bond is caused to branch, causing a crosslinking reaction.

  The skeleton structure of the molecular chain of the prepolymer having an isocyanate group at the molecular terminal is arbitrary, and specific examples include a polyurethane skeleton having a urethane bond, a polyester skeleton having an ester bond, and a polybutazine skeleton. One or more of these skeleton structures are employed as appropriate. In addition, when there is a urethane bond in the molecular chain, the terminal isocyanate group reacts with this urethane bond to produce an allophanate bond, and this allophanate bond also causes a crosslinking reaction.

  For these top coat films, if necessary, an anti-friction agent and matting agent composed of fine particles such as an ultraviolet absorber (selected from the above), alumina (especially spherical α-alumina is preferred), silica, and the like, silver Add antibacterial agents such as zeolite. When a matting agent is added, the top coat film functions as a gloss control coat.

  As described above, the top coat film is formed by using an organic compound having an OH group in the molecule as the UV absorber to be added to the surface sheet, and using a resin having an isocyanate group on the surface of the surface sheet. Then, when the UV absorber bleeds out over time and enters the top coat film, the OH group of the UV absorber and the isocyanate group in the top coat film react with urethane, and the top coat layer Since it is trapped in, the ultraviolet absorber is prevented from bleeding out over time. In particular, it is effective in the case of a polyolefin resin in which an organic ultraviolet absorber easily bleeds out, and is also suitable in the case of an ethylene-propylene-butene copolymer employed as a surface sheet in the present invention.

  A blend of these materials is formed into a film by a conventional method such as a calendar manufacturing method to obtain a colorless or colored transparent soft polypropylene resin film. As described above, the obtained film satisfies the conditions (1) to (8), particularly (7) and (8) required for the surface sheet of the decorative sheet. The thickness of the surface sheet is about 50 to 200 μm, preferably about 100 μm. The contact surface of the above surface sheet with the base material sheet is preferably subjected to an easy adhesion treatment such as application of an easy adhesion layer, corona discharge treatment, plasma treatment, and ozone treatment in the same manner as in the case of the base material sheet. Is done.

  The base sheet that is the colored film and the top sheet that is the colorless or colored transparent polypropylene resin film are laminated by a normal means. The lamination method may be melt extrusion coating (extrusion coating), fusion by hot pressing, or dry lamination using an adhesive such as a two-component curable polyurethane resin or polyester resin.

  Furthermore, a pattern layer is formed on the surface of the laminated sheet (decorative sheet) on the surface sheet side as necessary. The pattern processing may be embossing (heating press) as shown in FIG. 2C, concavo-convex pattern shaping 7 by hairline processing or the like, or pattern printing. At that time, if necessary, the embossed surface is subjected to an easy adhesion treatment such as the corona treatment described above and filled with colored ink. The pattern printing method, the type of pattern, the type of ink (or) paint, the binder, etc. may be the same as in the case of the base sheet. Furthermore, if necessary, colored ink can be filled in the concave and convex portions of the concave and convex pattern by a known wiping method.

  Preferably, a gloss adjusting protective coating layer is further formed thereon (may be a top coat film or a surface sheet). As the binder, chlorinated polyolefin, two-component cured polyurethane, and the like are preferable, and ionizing radiation curable resins can also be used. Specifically, the ionizing radiation curable resin is preferably a composition curable by ionizing radiation in which a prepolymer, a polymer and / or a monomer having a polymerizable unsaturated bond or a cationic polymerizable functional group in the molecule are appropriately mixed. Used. In addition, ionizing radiation means what has an energy quantum which can superpose | polymerize or bridge | crosslink among electromagnetic waves or a charged particle beam, and an ultraviolet-ray (UV) or an electron beam (EB) is normally used here.

  The ionizing radiation curable resin that forms a hard coating is specifically composed of radically polymerizable unsaturated groups such as (meth) acryloyl groups and (meth) acryloyloxy groups in the molecule, and cationically polymerizable functional groups such as epoxy groups. It consists of a monomer, prepolymer or polymer having two or more groups or thiols. These monomers, prepolymers or polymers are used alone or in combination. Here, for example, a (meth) acryloyl group is used to mean an acryloyl group or a methacryloyl group.

  Examples of the prepolymer having a radically polymerizable unsaturated group include polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, triazine (meth) acrylate, and the like. The molecular weight is usually about 250 to 10,000. As the polymer having a radically polymerizable unsaturated group, a polymer having a polymerization degree of about 10,000 or more is used.

  Examples of the prepolymer having a cationically polymerizable functional group include prepolymers such as epoxy resins such as bisphenol type epoxy resins and novolac type epoxy resins, and vinyl ether resins such as aliphatic vinyl ethers and aromatic vinyl ethers. Examples of the monomer having a radical polymerizable unsaturated group include monofunctional monomers of (meth) acrylate compounds such as methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenoxyethyl (meth) ) Acrylate and the like.

  Examples of polyfunctional monomers having radically polymerizable unsaturated groups include diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide tri (meth) ) Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

  As an example of the monomer having a cationic polymerizable functional group, the prepolymer monomer having the cationic polymerizable functional group can be used. Examples of the monomer having a thiol group include trimethylolpropane trithioglycolate and dipentaerythritol tetrathioglycolate.

  In the case of curing with ultraviolet rays or visible rays, a photopolymerization initiator is added to the ionizing radiation curable resin. In the case of a resin system having a radical polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether and the like can be used alone or in combination as a photopolymerization initiator. In the case of a resin system having a cationic polymerizable functional group, an aromatic diazonium salt, an aromatic sulfonium salt, an aromatic iodonium salt, a metatheron compound, a benzoin sulfonic acid ester or the like is used alone or as a mixture as a photopolymerization initiator. I can do this. The addition amount of these photopolymerization initiators is about 0.1 to 10% by weight with respect to 100% by weight of the ionizing radiation curable resin.

  In the case of matting, a matting (light diffusion) agent is added. As the matting agent, fine particles having a particle diameter of about 1 to 30 μm such as calcium carbonate, silica, alumina (especially spherical α-alumina is preferable), barium sulfate, urethane resin beads, polycarbonate resin beads and the like are effective. The film thickness is preferably about 1 to 100 μm. In the present invention, the base sheet and the surface sheet can be either stretched or unstretched sheets, but unstretched sheets are preferred from the viewpoint of embossing suitability and molding process suitability such as V-cut processing.

  The decorative sheet of the present invention can be laminated on another adherend (backing material) 31 as shown in FIG. In that case, when the decorative sheet itself does not adhere to the adherend, the decorative sheet is laminated through an appropriate easy-adhesive layer and an adhesive layer 4. In the case where the decorative sheet itself can be adhered to the adherend (by a thermal melting point or the like), the adhesive layer may be omitted.

  As the adherend, various shapes of articles such as flat plates of various materials, plate materials such as curved plates, sheets (or films), and three-dimensional shaped articles are targeted. The material used for any of the plate material, sheet (film), or three-dimensional shaped article includes wood veneer such as wood veneer, wood plywood, perch board, medium density fiberboard (MDF), and wood fiber such as wood fiberboard. Plate, metal such as iron, aluminum, acrylic resin, polycarbonate resin, ethylene / vinyl acetate copolymer, ethylene vinyl acetate, polyester resin, polystyrene, polyolefin resin, ABS, phenol resin, polyvinyl chloride, cellulose resin, rubber, etc. As materials used exclusively as plastic materials, plate materials or three-dimensional articles, ceramics such as glass and ceramics, cements such as ALC (lightweight lightweight concrete), non-cement ceramic materials such as calcium oxalate and gypsum, sheets exclusively (Or film) materials include fine paper and Japanese Paper etc., carbon, asbestos, potassium titanate, glass, there is a non-woven or woven fabric made of fibers such as synthetic resin.

  As a method for laminating these various adherends, for example, (1) a method of laminating by pressing with a pressure roller on a plate-like substrate with an adhesive layer interposed therebetween, (2) Japanese Patent Publication No. 50-19132 As described in Japanese Patent Publication No. 43-27488, a decorative sheet is inserted between both male and female molds for injection molding, both molds are closed, and molten resin is injected and filled from the male mold gate. After cooling, a decorative sheet is bonded and laminated on the surface of the resin molded product at the same time as molding, so-called injection molding simultaneous lamination method, (3) described in JP-B-56-45768, JP-B-60-58014, etc. The decorative sheet is opposed or placed on the surface of the molded product with an adhesive layer interposed therebetween, and the decorative sheet is laminated on the surface of the molded product by a pressure difference due to vacuum suction from the molded product side. Press lamination method, (4) Shoko 61 As described in Japanese Patent No. 5895, Japanese Patent Publication No. 3-2666, etc., while supplying a decorative sheet via an adhesive layer in the long axis direction of a columnar substrate such as a cylinder or a polygonal column, a plurality of A so-called lapping method in which decorative sheets are sequentially pressure-bonded and laminated on a plurality of side surfaces constituting a columnar body by rollers having different orientations. (5) Japanese Utility Model Publication No. 15-31122, JP As described in Japanese Patent Application Publication No. 48-47972 and the like, first, a decorative sheet is laminated on a plate-like base material via an adhesive layer, and then on the surface of the plate-like base material opposite to the decorative sheet, Cutting a groove with a V-shaped or U-shaped cross-section that reaches the interface with the plate-like substrate, and then applying an adhesive into the groove, then bending the groove to form a box or columnar body There are so-called V-cut or U-cut processing methods.

  The decorative sheet of the present invention is laminated on various adherends, subjected to a predetermined molding process, and used for various applications. For example, interior decorations for buildings such as walls, ceilings, floors, surface decorations for furniture such as window frames, doors, handrails, surface decorations for furniture or cabinets for light electrical / OA equipment, interior decorations for cars, trains, etc., aircraft interiors, ships Interior decoration, window glass makeup, etc.

The temperature-elongation dependency of the decorative sheet of the present invention has a temperature-elongation dependency similar to that of a decorative sheet mainly composed of a polyvinyl chloride sheet that is currently used, although the temperature range is about 15 ° C. is high. Thereby,
(1) It has an elongation rate, tear resistance, and flexibility that can be cut by V-cut, has good heat resistance, and has the effect of improving design by printing.
(2) Excellent embossing suitability compared to general olefin resin films.
In addition, an organic ultraviolet absorber having a hydroxyl group in the molecule is added to the surface sheet, and an ultraviolet coating is formed by forming a top coat layer made of a resin having an isocyanate group in the molecule on the surface side of the surface sheet. The agent is trapped in the top coat layer and bleeding over time is prevented.

Examples of the present invention will be described in detail below.
Example (1) Based on 60 parts by weight of isotactic polypropylene, 30 parts by weight of styrene-butadiene rubber as an elastomer, 10 parts by weight of calcium carbonate powder as an inorganic additive, and petal, yellow lead and titanium white as a color pigment A total of 5 parts by weight was added, and an opaque colored sheet was formed by blending 5 parts by weight of a heat stabilizer and a hindered amine radical scavenger to a thickness of 100 μm by a calendering method.
(2) After corona discharge treatment on both the front and back sides of the above colored sheet, urethane primer coat (hexamethylene diisocyanate + polyester polyol) on the back side, urethane primer coat (same as above) and cedar pattern (binder) on the front side Was a mixture of acrylic resin and vinyl chloride-vinyl acetate copolymer in a 1 to 1 weight ratio, and the pigment was valving). Gravure printing was performed to obtain a printed sheet.
(3) On the above printed sheet, a molecule as an ultraviolet absorber for a mixed polypropylene of 50 parts by weight of isotactic polypropylene and 50 parts by weight of atactic polypropylene as described in JP-B-6-23278 having a thickness of 80 μm. A soft transparent polyolefin film consisting of 3000 ppm of a benzotriazole-based UV absorber having a hydroxyl group therein and 5000 ppm of a hindered amine-based radical scavenger as a light stabilizer was subjected to corona discharge treatment on the back laminate surface, and then coated. An adhesive (made of acrylic polyol and hexamethylene diisocyanate) layer having a thickness of 10 μm was used to laminate as a surface sheet, and a wood grain conduit pattern was embossed on the surface of the surface sheet by hot pressing.
The embossed surface is subjected to corona discharge treatment, and then the embossed surface is filled with colored ink (the binder is made of 100 parts by weight of acrylic polyol and 8 parts by weight of hexamethylene diisocyanate, and the pigment is made of a dial and carbon black). A decorative sheet was obtained by applying a film (binder: 100 parts by weight of acrylic polyol and hexamethylene diisocyanate: 8 parts by weight, and matting agent: 5% by weight of silica particles (average particle size: 2 μm) added) at a thickness of 5 μm.
(4) From the obtained decorative sheet, a sample having a width of 5 mm × length of 10 mm was obtained, and when the elongation was measured while increasing the load to 5 ° C. at a rising temperature of 20 ° C. to 170 ° C. (TMA measurement), As shown by the curve in FIG. 1C, the decorative sheet was found to exhibit the same behavior at a temperature range of about 15 ° C. higher than the semi-rigid vinyl chloride sheet (the curve in FIG. 1A).

Comparative Example 1
(1) As a surface sheet and a base material sheet in Examples, a biaxially-stretched isotactic polypropylene (100% by weight of propylene) with a stretch ratio of 3 times and a thickness of 100 μm was used. Others were the same as in Example 1.
(2) When TMA measurement of the obtained decorative sheet was performed, as shown in FIG. 1B, it was found that the change in the physical property value with respect to the temperature change was steep, and the thermoforming conditions were extremely limited.

Comparative Example 2
The example was the same as the example except that the top coat film of the example was omitted.

[Performance evaluation test]
Table 6 shows the results of comparison of the physical properties of the decorative sheet of the example and the decorative sheet of the comparative example.
[Test method]
〔transparency〕
Immediately after the embossing, the lower pattern was visually observed through the surface sheet to confirm the presence or absence of cloudiness and gloss unevenness of the surface sheet.
[Interlayer adhesion]
The surface sheet and the base sheet of the decorative sheet cut to a width of 1 inch were pulled at an opening angle of 180 ° between them and a tensile speed of 50 mm / min, and the tension at the time of peeling was measured to obtain an adhesive force. The temperature at the time of measurement is 20 ° C.

〔Weatherability〕
Ultraviolet rays and artificial rain were exposed from the top sheet side of the decorative sheet using a carbon arc saddle type sunshine weather meter. The test conditions were a black panel temperature of 63 ° C. and an exposure time of 18 minutes / 120 minutes for 1000 hours. After the test, the presence or absence of discoloration, cracking, whitening, and sheet delamination of the decorative sheet was visually confirmed. The peel strength after exposure was also measured by the above method.
[Appropriate embossing] The shape reproducibility of the grain conduit groove unevenness was visually evaluated after embossing.
[Appropriate for V-cut processing] The obtained decorative sheet is laminated on a lauan plywood with a thickness of 5 mm using a two-component curable urethane resin adhesive so that the surface sheet side is the outside, and in an atmosphere of 40 ° C Cured for 3 days and bonded. Next, a groove having a V-shaped cross section that did not reach the decorative sheet was cut on the back surface of the plywood, and an adhesive was applied to the groove to bend the groove so as to close the groove, thereby making the plywood L-shaped. Then, the presence or absence of cracks, breakage, whitening, etc. of the decorative sheet on the plywood surface was visually confirmed. The temperature during processing is 20 ° C.
[Heating dimensional shrinkage]
The decorative sheet is heated in an atmosphere of 100 ° C. for 30 minutes, and the heat shrinkage ratio (%), that is, ((dimension after heating) − (dimension before heating)) × 100 / (dimension before heating) is longitudinal. It calculated | required about each of direction (MD) and width direction (TD).

The graph which shows the temperature-elongation relationship of various decorative sheets from which a material differs. It is sectional drawing explaining the decorative sheet by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Top sheet 3 ... Pattern 4 ... Easy adhesion layer (primer layer)
5, 7 ... Uneven pattern such as embossing 6 ... Colored ink 8 ... Pigment 31 ... Adhered body (flat plate)

Claims (3)

On a colored film as a base sheet consisting of polypropylene, elastomer, colorant, and inorganic filler as the main raw material, a molecule consisting of a mixed system of isotactic polypropylene and atactic polypropylene has a composite three-dimensional structure as a surface sheet. A colorless or colored transparent soft polypropylene-based resin film, in which a surface sheet formed by adding an organic ultraviolet absorber having a hydroxyl group in a molecule is laminated, and on the surface of the surface sheet, from a resin having an isocyanate group A decorative sheet formed by laminating a top coat film. The decorative sheet according to claim 1, wherein a pattern is applied to one or both of the base sheet and the top sheet of the decorative sheet. Elongation at break _{(T B)} is 400% or more, 100% residual elongation after elongation (PS ₁₀₀₎ 80% or less, and the ratio _M B / M at break Stress and _{(M B)} and at yield stress _{(M Y)} The decorative sheet according to claim 1 or 2, wherein a soft polypropylene resin composition having _Y of 1.0 or more is used.

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