JP4578512B2 - 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, as a decorative sheet used for the above-mentioned applications, a decorative sheet using a polyvinyl chloride film and decorated by printing, embossing, etc. (Japanese Patent Publication No. 28-5036, Japanese Patent Publication No. 58-14312) In recent years, a decorative sheet using the following resin has been proposed as an alternative to this.

  (I) A decorative sheet using a polyolefin film such as polyethylene or polypropylene (see JP-A-54-62255).

  (II) As an improved specification of the above (I), a polyolefin resin in which a polar functional group is graft-polymerized and an olefin-based thermoplastic elastomer are mixed (Japanese Patent Laid-Open No. 6-210808, Japanese Patent Laid-Open No. 4-504384) No. etc.), or a decorative sheet using a polyolefin resin mixed with a polyurethane resin using a compatibilizing agent (JP-A-7-26038 etc.).

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 conventionally proposed decorative sheet using the polyolefin resin as described above is not always satisfactory for the following reason. That is, for the surface decorative sheet used for interior / exterior of buildings, surface decorations such as joinery and furniture, vehicle interiors, etc., usually, the following functions (1) to (10) are required. This is because the conventional proposals do not necessarily satisfy these requirements.

  (1) Thermoformability comparable to polyvinyl chloride: Mechanical parameters such as elasticity, elongation and viscosity of the sheet change continuously and gently with increasing temperature, and strength with heating → cooling It is required that the deterioration of the material mechanical properties such as a decrease does not occur.

  (2) Creep deformation resistance: The exterior material and interior material are often subjected to a constant load by a fitting or furniture for a long time, and when the 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 bending such as V-cut processing is performed in cold weather, if the stress relaxation is insufficient, whitening, cracks, breakage, etc. are likely to occur in the bent portion, and cold bending strength is required.

  (4) Organic solvent resistance: It is required to prevent the decorative sheet 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, impact strength: These properties are required to prevent cracks in the bent part during V-cut processing.

  (6) Bending suitability: having an appropriate bending elastic modulus. It is required to make the followability of the decorative sheet at the bent portion sufficient.

  (7) Transparency: In the case of a decorative sheet comprising a top sheet / pattern / base sheet, high transparency is required for the top sheet (top film).

  (8) Embossing suitability: It is required that whitening and turbidity due to recrystallization do not occur even when heating and cooling accompanying embossing or the like are applied.

  (9) Easy adhesion: Excellent easy adhesion is required. In particular, in the case of adhesion between the base sheet and the adherend, it is desired to have good adhesion to a wider range of adhesives, that is, a wide range of options for adhesion. That is, it is required that delamination, discoloration, cracks, and the like hardly occur when exposed to sunlight and wind and rain.

  (10) Weather resistance: Excellent weather resistance is required.

  The conventional decorative sheet of the above-mentioned specification (I) is difficult to mass-produce industrially, and the polyolefin resin has a high crystallinity, so among the above conditions, in particular, (1), ( Conditions 5) to (10) are not fully satisfied. In addition, since the conventional (II) specification is mixed with an olefinic thermoplastic elastomer, the conditions (1), (5), (6) and (9) are improved, and thermoforming is performed. However, heat resistance, weather resistance, and transparency are 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. The object is to provide a decorative sheet having the same heat resistance, weather resistance and transparency as the sheet.

In order to solve the above-mentioned problems, the decorative sheet of the present invention has a direct or other layer on a colored base sheet composed mainly of a material containing polypropylene, an elastomer, a colorant, and an inorganic filler. A cured product layer of an ionizing radiation curable resin is formed, and the ionizing radiation curable resin contains urethane (meth) acrylate and an acrylic copolymer, and the mixing ratio of the two is 2: 8 to 8: 2. It is characterized by being. The molecular weight of the acrylic copolymer is preferably 10,000 to 30,000.
In order to solve the above problems, the decorative sheet of the present invention has a main material directly or other on a colored base sheet composed of a material containing polypropylene, an elastomer, a colorant, and an inorganic filler. A cured product layer of ionizing radiation curable resin is formed through the layer, an acrylic copolymer is mixed in the ionizing radiation curable resin, and the molecular weight of the acrylic copolymer is 10,000 to 30,000. Features .

  In the base material sheet used in the decorative sheet of the present invention, polypropylene (PP) is selected as the polyolefin that is the compounding base, as having excellent basic performance. Table 1 below shows the degree of satisfaction of polypropylene under the conditions (1) to (10) required for the decorative sheet.

* 1: During embossing, the degree of softening and fluidity of the sheet change sharply before and after the melting point, so the control range of processing conditions is narrow and it is difficult to control the conditions. In addition, the elongation decreases due to crystallization improvement by cooling.
* 2: Yield point stress is high.
* 3: The flexural modulus is too high.
* 4: There is a tendency of cloudiness due to fine crystal grains.
Therefore, by adding an elastomer, crystallization was inhibited and stress was absorbed and relaxed. The results are shown in Table 2 below.

  As shown in Table 2, each condition changes. As a result, the conditions (1), (5) and (6) were satisfied, but the creep resistance of (2) was somewhat lowered. In order to improve the creep resistance, an inorganic fine particle extender pigment was further added. The results are shown in Table 3 below.

  As shown in Table 3, it can be seen that the conditions changed. As a result, it was confirmed that the creep deformation resistance was also good, and that the materials satisfying the performances (1) to (6) and (9) as the base material sheet were obtained. (10) is judged to be an acceptable defect because it can be sufficiently compensated and improved by the layer formed on the surface of the base sheet).

  The decorative sheet of the present invention is excellent in thermoformability and weather resistance in addition to the properties of a decorative sheet using a conventional polyolefin resin, and the cured layer of ionizing radiation curable resin is a top film of a conventional decorative sheet. Excellent transparency. Moreover, it is excellent in the adhesiveness between the ionizing radiation curable resin layer and the substrate sheet, and is excellent in scratch resistance.

  The present invention is based on the above experimental results. Basically, the decorative sheet according to the present invention is a colored base material produced using a material containing main ingredients of polypropylene, an elastomer, a colorant, and an inorganic filler. A cured product layer of ionizing radiation curable resin is formed on the sheet directly or via another layer, and a patterned layer is provided on the colored substrate sheet and / or the cured product layer of the ionizing radiation curable resin. It is a thing.

Colored substrate sheet :
As the polypropylene contained in the colored base sheet of the decorative sheet of the present invention, isotactic polypropylene which is a polymer having a high degree of crystallinity and a small number of branched structures in the molecule is preferably used.

  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, butadiene rubber, butyl rubber, propylene / butadiene rubber, acrylonitrile / butadiene 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.

  In addition, a polyolefin resin obtained by crosslinking and polymerization of EPDM (ethylene propylene diene methylene linkage): a polyolefin resin mixed with EPR (ethylene propylene rubber) and polymerized: an amorphous polyolefin resin. These elastomers are appropriately crosslinked as required. As the crosslinking agent, known ones such as sulfur, aliphatic organic peroxides and aromatic organic peroxides are used.

  The added amount of the elastomer is 10 to 60% by weight, preferably about 30% by weight in the base sheet. If it is lower than 10% by weight, the temperature change of the mechanical parameter evaluated by the change accompanying the temperature change of the elongation at a constant load becomes too steep, and the improvement in easy adhesion becomes insufficient. Further, elongation at break and impact resistance are reduced, and if it exceeds 60% by weight, transparency, weather resistance and creep resistance are reduced.

  As the inorganic filler in the present invention, powders of calcium carbonate, barium sulfate, alumina, silica, clay, talc and the like are used. The average particle size is about 0.1 to 10 μm. As addition amount, it is about 1 to 60 weight% in a base material sheet, More preferably, it is about 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, tensile strength, 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, and is an inorganic pigment such as titanium white, zinc white, dial, vermilion, ultramarine, cobalt blue, titanium yellow, carbon black, etc. , Isoindolinone, Hansa Yellow A, quinacridone, permanent red 4R, organic pigments such as phthalocyanine blue, or metal pigments composed of foil powders such as dyes, aluminum and brass, foil powders such as titanium dioxide-coated mica, basic zinc carbonate, etc. A pearlescent pigment made of 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 300 μm, preferably about 100 μm.

Easy adhesion layer :
The surface of the base sheet is preferably subjected to easy adhesion treatment such as application of an easily adhesive resin, corona discharge treatment, plasma treatment, ozone treatment, and the like. In this specification, “adhesiveness” means not only the application of an easy-adhesive resin but also an easy-adhesive surface obtained by various surface treatments such as corona discharge treatment, plasma treatment, and solvent treatment. This includes cases where

  As the easy adhesion layer (also referred to as primer layer or anchor layer), acrylic resin, vinyl chloride-vinyl acetate copolymer, polyester resin, urethane resin, chlorinated polypropylene, chlorinated polyethylene, etc. can be used. Is desirable.

  These easy-adhesion layers are more effective when a polar functional group such as a carbonyl group, a hydroxyl group, or a carboxyl group is first applied to the surface of the base sheet by corona discharge treatment, plasma treatment, or ozone treatment, and then formed. .

  Acrylic resins that can be used for the easy-adhesion layer include poly (meth) acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate propyl, poly (meth) acrylate butyl, methyl (meth) acrylate, (Meth) butyl acrylate copolymer, (meth) ethyl acrylate / (meth) butyl acrylate copolymer, ethylene / (meth) methyl acrylate copolymer, styrene / methyl (meth) acrylate copolymer An acrylic resin composed of a homopolymer or a copolymer containing a (meth) acrylic ester such as (wherein (meth) acryl means acryl or methacryl) is used.

  Examples of the urethane resin that can be used in the easy-adhesion layer include a polyurethane having a polyol (polyhydric alcohol) as a main component and an isocyanate as a cross-linking agent (curing agent), and the polyol includes two or more in the molecule. For example, polyethylene glycol, polypropylene glycol, acrylic polyol, polyester polyol, polyether polyol, etc. are used. Examples of the isocyanate include polyvalent isocyanates having two or more isocyanate groups in the molecule, for example, aromatic isocyanates such as 2,4-tolylene diisocyanate, xylene diisocyanate and 4,4-diphenylmethane diisocyanate, or hexamethylene. Aliphatic (or alicyclic) isocyanates such as diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are used. Alternatively, a multimer or adduct of these isocyanates may be used.

Ionizing radiation curable resin layer :
The cured product layer of the ionizing radiation curable resin is provided for imparting surface physical properties such as contamination resistance and scratch resistance, or for imparting embossability, heat resistance, and thermoplasticity. Specifically, the resin that can be used for the ionizing radiation curable resin has a polymerizable unsaturated bond such as a (meth) acryloyl group or (meth) acryloyloxy group or a cationically polymerizable functional group such as an epoxy group in the molecule. A composition that can be cured by causing a crosslinking reaction, a polymerization reaction or the like by ionizing radiation in which a prepolymer, a polymer and / or a monomer are appropriately mixed is preferably 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 thickness of the cured product layer of the ionizing radiation curable resin is preferably 10 μm to 100 μm. Further, a UV absorber may be added to impart weather resistance to the cured product layer of the ionizing radiation curable resin. When a UV absorber is added, it is cured by irradiation with an electron beam.

  Specifically, the ionizing radiation curable resin that forms a hard coating film includes 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. Monomers, prepolymers, or polymers having two or more groups or thiols. These monomers, prepolymers or polymers can be 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 cationic polymerizable functional group include prepolymers of epoxy resins such as bisphenol type epoxy resins and novolak type epoxy resins, and vinyl ether type resins such as aliphatic vinyl ethers and aromatic vinyl ethers.

  Examples of monomers having a radically polymerizable unsaturated group include monofunctional monomers of (meth) acrylate compounds such as methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and phenoxyethyl (meth) acrylate. Etc.

  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 order to impart embossability to the ionizing radiation curable resin layer, urethane (meth) acrylate, more preferably a monofunctional monomer of acrylate, is used. In order to impart thermoplasticity, an acrylic copolymer is mixed. To do. The mixing ratio of urethane (meth) acrylate and acrylic copolymer is preferably 2: 8 to 8: 2. However, the urethane (meth) acrylate ratio is preferably 4 or more in consideration of bending resistance, and 6 or less is preferable in consideration of contamination resistance. In this case, it is desirable that the molecular weight of the urethane (meth) acrylate is 100 to 300, and the molecular weight of the acrylic copolymer is 10,000 to 30,000.

When curing with ultraviolet light or visible light, 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. be able to.
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.

  Spherical particles may be mixed and dispersed for the purpose of further adding scratch resistance to the ionizing radiation curable resin. The material of the spherical particles may be higher than that of the cross-linking curable resin, and either inorganic particles or organic resin particles can be used, but inorganic particles are recommended in terms of wear resistance and hardness. The difference in hardness between the spherical particles and the cross-linkable curable resin is measured by a method such as Mohs hardness or Vickers hardness. For example, when expressed in terms of Mohs hardness, one or more is preferable.

  Specific examples of the material of the spherical particles include inorganic particles such as α-alumina, silica, chromium oxide, iron oxide, diamond, and graphite, and organic resin particles such as synthetic resin beads such as crosslinked acrylic. Particularly preferable granular particles include spherical α-alumina because they are very hard and have a great effect on wear resistance, and it is relatively easy to obtain spherical particles.

  The spherical particles only need to be surrounded by a smooth curved surface, such as a true sphere, or a spheroid with a flat sphere and a shape close to the sphere or spheroid. The spherical particles are particularly preferably spherical with no protrusions, corners, valleys or depressions on the particle surface, and so-called cutting edges. Spherical particles significantly improve the wear resistance of the surface resin layer itself, compared to irregularly shaped particles of the same material, and do not wear the coating device, and other things that come into contact with the coating after it is cured Is not worn, and the transparency of the coating film is also increased. This is particularly effective when there is no cutting edge.

These spherical particles have an average particle diameter of about 1 to 10 μm, and the amount added is usually about 5 to 30 parts by weight with respect to 100 parts by weight of the resin.
In particular, in order to emboss and wipe the cured layer of ionizing radiation curable resin, the following methods 1) to 3) may be mentioned.

  1) As disclosed in JP-A-57-87318, JP-B-57-22755, JP-B-63-50066, etc., an ionizing radiation curable resin is filled in at least the recesses of the roll intaglio and After the base sheet is brought into contact and the resin is held between the base sheet and the roll intaglio, the resin is cured by irradiating with ionizing radiation, and then the base sheet and the cured product layer are formed from the roll intaglio. Is formed by forming a base sheet having a concavo-convex pattern, wiping the base sheet by a known method described in Japanese Patent Publication No. 58-14312 and filling a concave portion of the concavo-convex pattern with colored ink. is there.

  2) In another embossing and wiping process, an ionizing radiation curable resin is filled in at least the recesses of the roll intaglio and the base sheet is brought into contact with the resin to hold the resin between the base sheet and the roll intaglio. In this state, the resin is semi-cured by irradiating ionizing radiation to form a sheet having a concavo-convex pattern, and after wiping the sheet and filling the concave part of the concavo-convex pattern with colored ink, This is a method of completely irradiating the ionizing radiation curable resin by irradiating the uneven pattern with ionizing radiation again.

  3) Further, as an embossing and wiping method of the object, an ionizing radiation curable resin is applied on a base sheet, and the ionizing radiation curable resin is completely cured or incompletely cured by irradiating with ionizing radiation. This is a method of forming a non-adhesive solid at room temperature and then forming the resin layer and an uneven pattern subjected to embossing as described later.

Pattern layer :
The pattern layer can be formed on either or both of the base sheet and the ionizing radiation curable resin layer. The pattern forming process may be pattern printing, embossing (heating press), forming a concavo-convex pattern by hairline processing, etc., and filling a concave portion of the concavo-convex pattern with colored ink by a known wiping method. You can also

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

  For ink or paint, as binder resin, 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. , One or a mixture of two or more. To this, a material added with known pigments as listed above is used.

  When printing directly on the base sheet, chlorinated polyolefin resin, urethane resin, etc. are preferable as the binder resin in terms of adhesiveness, but other binder resins can be used if an easy-adhesive primer is appropriately selected to form a layer. Give enough 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. In addition, the same color ink as described above can be used for the mirror flat surface. However, in terms of abrasion resistance, it is preferable to use a two-component curable urethane resin as a binder resin.

  In addition to embossing, the above-described method can also be applied to apply a concavo-convex pattern to the cured layer of the ionizing radiation curable resin.

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

Application of decorative sheet :
FIG. 1 representatively shows one embodiment of the layer structure of the decorative sheet 10 of the present invention described above, and a patterned layer 2 by printing is formed on the colored substrate film 1 as necessary. Further, a cured product layer 3 of ionizing radiation curable resin is formed thereon, and an uneven pattern 4 is formed on the cured product layer 3 of the ionizing radiation curable resin as necessary. Also good.

  FIG. 2 shows a state in which the decorative sheet 10 of the present invention shown in FIG. 1 is bonded to an adherend (backing material) 20. When the decorative sheet 10 itself does not adhere to the adherend 20, the decorative sheet 10 is laminated via an appropriate easy adhesion layer or adhesive layer 5. When the decorative sheet 10 itself can be adhered to the adherend 20 (by heat fusion or the like), the easy-adhesion layer or the adhesive layer 5 may be omitted.

  As the adherend, plate materials such as flat plates and curved plates of various materials, sheets (or films), or various three-dimensional articles (molded products) are targeted. For example, as shown in FIG. 3, with respect to the uneven three-dimensional object 21, the colored substrate film 1, the cured product layer 3 of ionizing radiation curable resin formed on the colored substrate film 1, and the ionizing radiation curable type. The decorative sheet of the present invention comprising the pattern layer 2 formed on the cured resin layer 3 can be adhered.

  As an adherend, as a material used for either a plate material or a sheet (film), a wood board, a wood plywood, a particle board, a water fiber board such as a wood fiber board such as a medium density fiber board (MDF), iron, Metals such as 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 and other resins It is done.

  Examples of the material used exclusively as a substrate or as a three-dimensional article include glass, ceramics such as ceramics, cement such as ALC (foamed lightweight concrete), non-ceramic ceramic materials such as calcium oxalate and gypsum. .

  Examples of the material used exclusively as a sheet (or film) as the adherend include paper such as high-quality paper and Japanese paper, and nonwoven fabric or woven fabric made of fibers such as carbon, asbestos, potassium titanate, glass, and synthetic resin. .

Examples of methods for laminating these various adherends include the following methods 1) to 5). That is,
1) A method of laminating by pressing a plate-like substrate with a pressure roller with an adhesive layer interposed therebetween,
2) As described in Japanese Patent Publication No. 50-19132, Japanese Patent Publication No. 43-27488, etc., a decorative sheet is inserted between both male and female molds for injection molding, both molds are closed, After injection filling with molten resin from the gate, it is cooled and the decorative sheet is bonded and laminated on the surface simultaneously with the molding of the resin molded product, so-called injection molding simultaneous laminating method,
3) As described in JP-B-56-45768, JP-B-60-58014, etc., the decorative sheet is placed on the surface of the molded product through an adhesive or placed on the surface of the molded product. A so-called vacuum press lamination method, in which a decorative sheet is laminated on the surface of a molded product by a pressure difference due to vacuum suction of
4) As described in Japanese Patent Publication No. 61-5895, Japanese Patent Publication No. 3-2666, etc., in the major axis direction of a columnar substrate such as a cylinder or a polygonal column, a decorative sheet is interposed between the adhesive layers. A so-called wrapping method, in which a decorative sheet is sequentially pressure-bonded and laminated on a plurality of side surfaces constituting a columnar body by a plurality of differently oriented rollers,
5) As described in Japanese Utility Model Publication No. 15-31122, JP-A-48-47972, etc., a decorative sheet is first laminated on a plate-like substrate via an adhesive layer, and then a plate-like substrate. A groove having a V-shaped or U-shaped cross-section reaching the interface between the decorative sheet and the plate-like base material was cut on the surface opposite to the decorative sheet, and then an adhesive was applied in the groove. Above, the so-called V-cut or U-cut processing method of bending the groove and forming a box or a columnar body can be used.

  4 and 5 are explanatory views for applying the decorative sheet of the present invention to an adherend that performs the V-cut processing method. FIG. 4 shows a cross-sectional view of the decorative sheet 10 bonded to the adherend 22 via the adhesive layer 5, and shows a state where the V-shaped groove 6 is cut on the adherend 22. Yes. FIG. 5 shows a state in which the bonded body of FIG. 4 is bent at the V-shaped groove of the adherend 22.

  The decorative sheet of the present invention can be used for various purposes by laminating on various adherends and applying a predetermined molding process. For example, interior decorations of buildings such as walls, ceilings, floors, surface makeup of furniture such as window frames, doors, handrails, surface makeup of cabinets of low-electricity and OA equipment such as furniture such as bags or television receivers, automobiles, It can be used for vehicle interiors such as trains, aircraft interiors, ship interiors, and window glass makeup.

  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 as an inorganic additive, and 5 weights of titanium white, petal, and carbon black as coloring pigments Partly added and 5 parts by weight of a heat stabilizer and a hindered amine radical scavenger were blended to form a film having a thickness of 100 μm by a calendering method to produce an opaque colored base sheet.

  The front and back surfaces of the colored substrate sheet produced in the above process are subjected to corona discharge treatment for easy adhesion treatment, and the binder is made of hexamethylene diisocyanate and acrylic polyol, and the pigment is made of a petal. Gravure printing of wood grain pattern. Next, 3 parts by weight of a hindered amine radical scavenger is added to 100 parts by weight of the electron beam curable resin having a mixing ratio of monofunctional urethane acrylate monomer and acrylic copolymer of 3: 2 on the printed surface, and A mixture to which 2 parts by weight of a benzotriazole-based ultraviolet absorber was added was applied by a comma coating method to a thickness of 50 μm, and then crosslinked and cured by electron beam irradiation. Next, the electron beam curable resin-coated surface was mirror finished by hot embossing with a mirror roll.

  The decorative sheet of Example 1 thus obtained was examined for bending resistance, stain resistance, and embossability (texture transferability, emboss fastness). The results are shown in Table 4 below. In addition, about the bending resistance, the presence or absence of the crack and fracture | rupture of the sheet | seat at the time of V cut process was investigated.

[Comparative Example 1]
Except for using a 100 μm thick biaxially stretched isotactic polypropylene sheet having a stretch ratio of 3 as the colored substrate sheet of Example 1, an easy pattern treatment was performed in the same manner as in Example 1, and an abstract pattern Printed. A two-component curable urethane resin composed of hexamethylene diisocyanate and acrylic polyol is applied to the back surface of a sheet of 50 μm thick biaxially stretched isotactic polypropylene with a stretch ratio of 3 times on the printed surface. Lamination was performed using an adhesive. Next, the surface was mirror-finished by hot embossing with a mirror roll in the same manner as in Example 1 to produce a decorative sheet of Comparative Example 1. The decorative sheet of Comparative Example 1 thus obtained was examined for bending resistance, stain resistance, and embossability (texture transferability, emboss fastness). The results are shown in Table 4 below.

[Performance evaluation test]
Table 5 below shows the results of comparison of the physical properties of the decorative sheets of Example 1 and Comparative Example 1 based on the test methods described below.

1. Transparency The haze value is measured with a direct reading haze meter manufactured by Toyo Seiki Co., Ltd. Measured with a single polyolefin resin sheet layer without decorative treatment.

2. Weather resistance Irradiated with a carbon arc vertical sunshine weather meter for up to 3000 hours (irradiation conditions: black panel temperature 63 ° C; water spray 12 minutes / in 1 hour), the appearance changes such as cracks, whitening, and discoloration became remarkable. Stop at a point (visual measurement). The sample after irradiation is evaluated visually.

3. Heat resistance Heat for 3 minutes in an 80 ° C. atmosphere, and visually check the discoloration state before and after that.

4). Sheet cracking / breaking during V-cut processing The base sheet side of the decorative sheet is adhered and laminated to a lauan plywood with a thickness of 10 mm using an adhesive of ethylene / vinyl acetate copolymer emulsion, and the decorative sheet side of the plywood On the opposite side, a groove having a V-shaped cross section reaching the interface between the plywood and the adhesive layer is cut, and an adhesive of an ethylene / vinyl acetate copolymer emulsion is applied in the groove, and the groove is closed. In this manner, the plywood is bent to be bent into an L shape (cross section). The atmospheric temperature during processing is 10 ° C.

5). Heating dimensional shrinkage The decorative sheet is heated in an atmosphere of 100 ° C. for 30 minutes, and the heat dimensional shrinkage (%) represented by the following formula (1) is measured for each of the longitudinal direction (MD) and the width direction (TD). To do.

6). Adhesive strength Prepared decorative sheet laminated plywood similar to the one evaluated for V-cut processing, and in order to measure the adhesive strength between the decorative sheet and lauan plywood, the peeling angle of the contact angle between the decorative sheet and the plywood is 180 degrees Perform a tensile test at. Specifically, a decorative sheet sample cut out to a width of 10 mm was pulled under the conditions of a tensile speed of 50 m / min and an ambient temperature of 20 ° C. in a direction perpendicular to the width direction and the tensile direction of each layer being 180 degrees. And measure the tension at the time of peeling at the interface between layers.

7). Scratch resistance The sample surface is reciprocated 10 times with # 0000 steel wool and rubbed.

  According to Table 5, the cured product layer of the ionizing radiation curable resin in the decorative sheet of the present invention is excellent in transparency and weather resistance, and is excellent in heat moldability such as heat resistance and heat shrinkage. Furthermore, there is no sheet cracking / breaking at the time of V-cut, and the uneven surface pattern by the embossed plate can be faithfully reproduced on the entire surface, and the interlayer adhesion and scratch resistance are excellent.

The one aspect | mode of the layer structure of the decorative sheet of this invention is shown. The state which adhered the decorative sheet of this invention shown in FIG. 1 to the to-be-adhered body (backing material) is shown. The state which adhered the decorative sheet of this invention with respect to the uneven | corrugated solid object is shown. The explanatory view which applies the decorative sheet of the present invention to the adherend which performs V cut processing method is shown, and the section of what bonded the decorative sheet to the adherend in which the V-shaped groove was cut through the adhesive layer The figure is shown. The explanatory view which applies the decorative sheet of the present invention to the adherend which performs V cut processing method is shown, and shows the state bent in the V-shaped groove.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Colored base film 2 Pattern layer 3 Cured material layer of ionizing radiation curable resin 4 Concavity and convexity pattern 5 Adhesive layer 6 V-shaped groove 10 Cosmetic sheet 20,22 Adhered body 21 Concavity and convexity three-dimensional object

Claims (10)

A cured material layer of an ionizing radiation curable resin is formed directly or via another layer on a colored base sheet composed of a material including a polypropylene, an elastomer, a colorant, and an inorganic filler as a main raw material, A decorative sheet characterized in that urethane (meth) acrylate and an acrylic copolymer are contained in an ionizing radiation curable resin, and a mixing ratio of the two is from 2: 8 to 8: 2 . A cured material layer of an ionizing radiation curable resin is formed directly or via another layer on a colored base sheet composed of a material including a polypropylene, an elastomer, a colorant, and an inorganic filler as a main raw material, An acrylic copolymer is mixed in the ionizing radiation curable resin,
A decorative sheet, wherein the acrylic copolymer has a molecular weight of 10,000 to 30,000. The decorative sheet according to claim 1, wherein the acrylic copolymer has a molecular weight of 10,000 to 30,000. The decorative sheet according to claim 1 or 3 , wherein the urethane (meth) acrylate has a molecular weight of 100 to 300.   The decorative sheet according to any one of claims 1 to 4, wherein the polypropylene is isotactic polypropylene.   The said inorganic filler is 1 to 60 weight%, The decorative sheet of any one of Claim 1 thru | or 5 characterized by the above-mentioned.   The decorative base sheet according to any one of claims 1 to 6, wherein the colored base sheet contains a radical scavenger.   The decorative sheet according to any one of claims 1 to 7, wherein spherical α-alumina particles are added to the cured product layer of the ionizing radiation curable resin.   The decorative sheet according to any one of claims 1 to 8, wherein an ultraviolet absorber is added to the cured product layer of the ionizing radiation curable resin.   The decorative sheet according to any one of claims 1 to 9, wherein a pattern layer is provided on the colored substrate sheet and / or a cured product layer of the ionizing radiation curable resin.

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