JP2006116895A - Laminated sheet for thermoforming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated sheet for thermoforming which can manufacture a molded article which uses a supporting substrate layer comprising a plurality of laminated sheets and has no deformation, wherein also the above supporting substrate layer does not easily cause curls by heat and does not spoil design nature which an ornament layer has. <P>SOLUTION: The laminated sheet for thermoforming comprises a transparent or translucent thermoplastic film layer, an ornament layer and a supporting substrate layer which are laminated in this order. This supporting substrate comprises three laminated layers of a polyolefin based resin layers. These three layer are (1) a layer (layer A) which does not contain an inorganic filler or contains an inorganic filler having a mean particle diameter of 4 μm and below and adjoins the ornament layer, (2) a layer (layers C) which contains an inorganic filler which is within the range of ±10 mass% to the inorganic filler content of the layers A, and (3) a layer (layers B) which is pinched by the layer A and the layer C. In addition, the laminated sheet for thermoforming has the sum total of the inorganic filler content of the layer B and the layer C of 5-60 mass%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminate sheet for thermoforming, particularly a laminate sheet for molding that is useful as a decorative sheet that does not require exterior coating of automobile-related members, building material members, home appliances, and the like.

When manufacturing colored resin molded parts, acrylic film with high transparency and excellent design, such as acrylic, and decorative layer, and polyolefin film that is often used for industrial purposes for thermoforming and injection molding There is known a method in which a molding sheet on which the supporting base material layers are laminated is integrally molded during injection molding. However, the thermoplastic film and polyolefin film differ greatly in the thermal shrinkage rate during thermoforming. Therefore, when a thermoforming is performed after forming a sheet-like laminate, a good molded product cannot be obtained. There was a problem.

On the other hand, the support base material layer is composed of a laminate of a plurality of polypropylene film layers, and at least the polypropylene film layer far from the acrylic film contains an olefinic rubber and a filler, thereby forming a three-dimensional shape of the molded product. There has been proposed a decorative sheet for preforming that can reduce the deformation (for example, see Patent Document 1).
However, although the laminated sheet of the acrylic film and the polypropylene film reduces the deformation of the molded product after molding, the support base material layer laminated with the polypropylene film has a configuration in which the thermal contraction rate of each layer is different. Therefore, there is a problem that the supporting base material layer itself is curled.

JP 2000-355082 A

  An object of the present invention is a laminated sheet for thermoforming that can produce a molded article without deformation by using a supporting substrate layer constituted by a plurality of laminated sheets, and the supporting substrate layer is also heated. It is an object of the present invention to provide a thermoformed laminated sheet which does not easily cause curling due to, and does not impair the design properties of the decorative layer.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors are a laminated sheet for molding in which a thermoplastic film layer for transparent or translucent molding, a decorative layer, and a supporting base material layer are laminated in this order. By including an inorganic filler in the base material layer, the difference in thermal shrinkage between the thermoplastic film layer and the support base material layer is reduced, and the support base material layer has a specific three-layer structure, thereby decorating The inventors have found that the high designability of the layer can be maintained and the support base material layer itself can be prevented from curling due to heat shrinkage, and the present invention has been completed.

That is, the present invention is a laminated sheet for thermoforming in which a transparent or translucent thermoplastic film layer, a decorative layer, and a supporting base layer are laminated in this order, and the supporting base layer is a polyolefin resin having three layers. Consisting of a stack of layers, the three layers
1) a layer (layer A) adjacent to a decorative layer that does not contain an inorganic filler or has an average particle diameter of 4 μm or less;
2) a layer (layer C) in which the content of the inorganic filler is within ± 10% by mass with respect to the inorganic filler content of the layer A;
3) A laminated sheet for thermoforming, which is a layer (layer B) sandwiched between layer A and layer C, and the total inorganic filler content of layers A, B and C is 5 to 60% by mass. provide.

  By the means described above, it is possible to provide a laminate sheet for molding that does not deform the molded body with respect to the spreadability required at the time of molding, that is, 200% spread by the heating vacuum forming method. In addition, the support base material layer used for the production of the molding laminated sheet is also free from deformation such as curling in the production process, and does not impair the design properties of the decorative layer.

Embodiments of the laminated sheet for thermoforming according to the present invention will be described in detail below.

(Transparent or translucent thermoplastic film)
As the transparent or translucent thermoplastic film used in the present invention, a transparent or translucent single layer or multilayer film which may contain a colorant and which has a spreadability by heating is used.

  A film mainly composed of a thermoplastic resin having a softening point in the range of 30 to 300 ° C. is preferable in order to perform a heat forming process such as vacuum forming. For example, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, Thermoplastic resins such as acrylic resins, silicon-acrylic resins, ionomers, polystyrene, polyurethane, nylon, ethylene-vinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluorinate, and polyvinylidene difluorate are preferably used. Among these, a sheet made of polyvinylidene difluorate or an acrylic resin is preferable from the viewpoints of integral molding possibility and weather resistance. The thickness is not particularly limited, but is preferably in the range of 30 to 2000 μm, more preferably 50 to 500 μm, since the coating property of the ink protective layer is good.

(Decoration layer)
As for the decoration layer which the lamination sheet for thermoforming of this invention has, a metal vapor deposition layer and an ink layer are mentioned. Furthermore, as an ink layer, the ink which has a mirror-like metallic luster containing a metal thin film strip can be obstructed.

(ink)
The ink used for the ink layer may be a commonly used general-purpose ink. The laminated sheet for heat shaping according to the present invention has a mirror-like metallic luster using an ink having a mirror-like metallic luster (hereinafter referred to as a high-brightness ink) in which metal thin film strips are dispersed in a binder resin. It is suitably used for a thermoformed laminated sheet having excellent visual properties. It is preferable that content with respect to the non volatile matter in the ink of a metal thin film piece is the range of 3-60 mass%. High-gloss inks using thin metal film strips are aligned with the metal thin film strips parallel to the surface of the object when the ink is printed or applied. Unobtainable high-brightness mirror-like metallic luster is obtained. Further, instead of applying the ink of the metal thin film strip, the metal may be vapor-deposited by a direct vapor deposition method and used instead of the ink.

(Metal thin film strip)
Aluminum, gold, silver, copper, brass, titanium, chrome, nickel, nickel chrome, stainless steel, etc. can be used as the metal of the metal thin film strip used in the high gloss ink used in the ink layer. As a method for making a metal into a thin film, in the case of a metal having a low melting point such as aluminum, it is a foil if it has malleability, such as aluminum, gold, silver, copper, etc. , Sputtering and the like. Among these, the metal thin film strip obtained from the vapor deposition metal thin film is preferably used. The thickness of the metal thin film is preferably 0.01 to 0.1 μm, more preferably 0.02 to 0.08 μm. The size in the surface direction of the thin metal thin film dispersed in the ink is preferably 5 to 25 μm, more preferably 10 to 15 μm. When the size is less than 5 μm, the brightness of the coating film becomes insufficient, and when it exceeds 25 μm, the metal thin film strips are difficult to orient and decrease in brightness, and ink is printed or applied by gravure or screen printing. Doing so will cause clogging of the plate.

  In the following, a method for producing a metal thin film strip will be described by taking a particularly preferable vapor deposition method as an example. A polyolefin film, a polyester film, etc. can be used for the support body film which vapor-deposits a metal. First, a release layer is provided on the support film by coating, and then a metal is deposited on the release layer so as to have a predetermined thickness. A top coat layer is applied to the surface of the deposited film to prevent oxidation. The same coating agent for forming the release layer and the top coat layer can be used.

  Resin used for a peeling layer or a topcoat layer is not specifically limited. Specific examples include cellulose derivatives, acrylic resins, vinyl resins, polyamides, polyesters, EVA resins, chlorinated polypropylene, chlorinated EVA resins, petroleum resins, and the like. Solvents include aromatic hydrocarbons such as toluene and xylene, aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane, esters such as ethyl acetate and propyl acetate, methanol, ethanol and isopropyl alcohol. Alcohols, ketones such as acetone and methyl ethyl ketone, and alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and propylene glycol monomethyl ether can be used.

  The metal vapor-deposited film is immersed in a solvent that dissolves the release layer and the topcoat layer and stirred. After the metal vapor-deposited film is peeled from the support film, the metal vapor-deposited film is further stirred to reduce the size of the metal thin film strip. Set to 5 to 25 μm, filter and dry. The solvent is not particularly limited except that it dissolves the resin used for the release layer or the topcoat layer. Even when the metal thin film is formed by sputtering, the metal thin film can be formed by the same method as described above. When using a metal foil, it may be pulverized to a predetermined size with a stirrer as it is in a solvent.

  The metal thin film strip is preferably surface-treated in order to enhance dispersibility in the ink. Examples of the surface treating agent include organic fatty acids such as stearic acid, oleic acid, and palmitic acid, and cellulose derivatives such as methylsilyl isocyanate, nitrocellulose, cellulose acetate propionate, cellulose acetate butyrate, and ethyl cellulose. To adsorb on the surface of the metal thin film strip.

(Binder resin)
As the binder resin, those conventionally used in conventional gravure ink, flexo ink, screen ink, paint or the like can be used. Specifically, for example, acrylic resins for paint, vinyl chloride resins, vinylidene chloride resins, vinyl chloride-vinyl acetate resins, ethylene-vinyl acetate resins, polyolefin resins, chlorinated olefin resins, polymerization resins such as ethylene-acrylic resins, Alternatively, a polyurethane resin for paint, a polyamide resin, a urea resin, an epoxy resin, a polyester resin, a petroleum resin, a cellulose derivative resin and the like are preferably used. In addition, those obtained by chemically bonding polar resins such as carboxylic acid group, phosphoric acid group, sulfonic acid group, amino group and quaternary ammonium base to these resins may be used or used in combination.

(Additive)
High gloss ink used in the ink layer, if necessary, defoaming, settling prevention, pigment dispersion, fluidity modification, antiblocking, antistatic, oxidation in the ink, unless it impairs design and spreadability. Various additives used in conventional gravure inks, flexo inks, screen inks, paints and the like can be used for the purpose of prevention, light stability, ultraviolet absorption, internal crosslinking and the like. Examples of such additives include coloring pigments, dyes, waxes, plasticizers, leveling agents, surfactants, dispersants, antifoaming agents, chelating agents, polyisocyanates, and the like.

(solvent)
As the solvent used in the high-gloss ink used in the ink layer, a known and commonly used solvent used in conventional gravure ink, flexo ink, screen ink, paint or the like can be used. Specifically, for example, aromatic hydrocarbons such as toluene and xylene, aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane, esters such as ethyl acetate and propyl acetate, methanol, ethanol, isopropyl alcohol and the like Alcohols, ketones such as acetone and methyl ethyl ketone, and alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and propylene glycol monomethyl ether.

(Preparation method of high brightness ink)
Generally, in order to stably disperse the ink blending raw material, the pigment and other additives are finely divided to submicron by kneading using a roll mill, ball mill, bead mill, or sand mill. However, the metal thin film strip to be blended in order to express metallic luster in the high gloss ink used for the ink layer of the molding laminated sheet having excellent sharpness is preferably 5 to 25 μm. When the above-mentioned kneaded meat is performed, the metal thin film pieces become fine particles, and the metallic luster is extremely lowered. Therefore, in the present invention, it is desirable not to perform kneading, but to simply mix the above-mentioned blending raw materials into an ink. For this purpose, for the purpose of improving dispersibility, it is preferable to surface-treat the metal thin film strip as described above.

(Printing or coating method)
The ink layer of the laminated sheet for molding of the present invention, the ink that may be further laminated to the ink layer, and the printing or coating method of the adhesive are printing methods such as gravure printing, flexographic printing, screen printing, gravure coater, Coating methods such as a gravure reverse coater, a flexo coater, a blanket coater, a roll coater, a knife coater, an air knife coater, a kiss touch coater, a kiss touch reverse coater and a comma coater, a comma reverse coater, and a micro gravure coater can be used. If the ink film thickness is too thin, the concealability tends to be inferior and the design property tends to be impaired. If it is too thick, the orientation of the metal thin film strips tends to be non-uniform. For this reason, as a film thickness of an ink layer, 5 micrometers or less are preferable, 0.05-5 micrometers is more preferable, Especially preferably, it is 0.5-3 micrometers.

(Supporting substrate layer)
The support base material layer used in the present invention has a laminated structure of three polyolefin resin layers. That each layer is a polyolefin resin layer means that 50% by mass or more of the resin constituting each layer is a polyolefin resin. Each layer constituting the supporting base material layer is a polypropylene resin or a linear low density polyethylene (L-LDPE) resin that has sufficient strength even when unstretched and has excellent thermoformability such as vacuum forming and pressure forming. It is more preferable to use as a main component. Furthermore, by blending these resins with polyethylene-based resins or rubber-like resins, the shapeability of molded products having complicated shapes such as automotive exterior parts is improved, and excellent impact strength is exhibited. be able to.
Here, a polypropylene resin or a linear low density polyethylene resin as a main component means that 50% by mass or more of the resin constituting each layer of the support base layer is a polypropylene resin or a linear low density polyethylene resin. Moreover, it is preferable that a polypropylene resin or a linear low density polyethylene resin is 30 mass% or more with respect to the whole constituent material of a support base material layer.

Polypropylene resin, which is preferably used as a supporting base material layer for producing a molded article for insert molding, and a resin mainly composed of a linear low-density polyethylene resin, have a molding shrinkage with a translucent molding thermoplastic film layer. The difference is likely to increase.
When an inorganic filler is added to the resin of the supporting base layer, the molding shrinkage can be controlled to be small, and the difference in molding shrinkage between the supporting base layer and the thermoplastic film layer laminated thereon is reduced. Can do.
For this reason, by adding an inorganic filler, the molding shrinkage rate of the support base material layer can be reduced, the difference in molding shrinkage rate from the thermoplastic film can be reduced, and curl deformation can be suppressed. The molding shrinkage rate of the supporting base material layer is not particularly limited as long as deformation does not occur. However, the difference in molding shrinkage rate between the thermoplastic film layer and the supporting base material layer is preferably 0.5% or less, more preferably 0. .4% or less.

  In the present invention, the support base material layer has a three-layer structure, and the content distribution of the inorganic filler in the support base material layer can be controlled by controlling the content of the inorganic filler contained in the three layers. . As a result, curling of the laminated sheet for thermoforming was prevented, the influence of unevenness on the decorative layer was reduced, and the support base material layer itself was also able to be resistant to curling due to heat.

The addition amount of the inorganic filler to the entire supporting base material layer is added in a sufficient amount so as to approach the molding shrinkage of the thermoplastic resin used for the transparent or translucent molding thermoplastic film layer. It is preferable to add an inorganic filler so that the difference in molding shrinkage in the molding process between the thermoplastic film layer and the support base material layer is within 0.5%.
On the other hand, in order to obtain good vacuum formability and sufficient impact strength as a molded body, the added amount of the inorganic filler is preferably 10 to 40% by mass, and preferably 10 to 30% by mass with respect to the entire support base material layer. More preferably.

The thickness of the entire supporting substrate layer is preferably 10 μm to 2000 μm, and more preferably 50 μm to 1000 μm because thermoformability is improved.

(Layer A)
Since the support base material layer is adjacent to the decoration layer, the unevenness of the support base material layer gives the decoration layer an unevenness, which impairs the design properties of the decoration layer. In particular, when the ink layer is a metal vapor deposition layer, the metallic luster is reduced due to the effect of unevenness. In addition, when the decoration layer is made of ink having a mirror-like metallic luster containing metal thin film strips, if the support base layer is uneven, the metal thin film strips are oriented substantially parallel to the support base layer. It becomes difficult to do so, and the orientation is disturbed. For this reason, the vividness of the metallic luster due to the metal thin film strips is impaired.

The support base material layer of the present invention has a three-layer structure, and the layer A adjacent to the decoration layer does not contain an inorganic filler, or when it contains an inorganic filler, the average particle diameter is 4 μm or less. Can prevent unevenness. In particular, it is possible to maintain the sharpness of a mirror-like metallic gloss layer produced by an ink having a mirror-like metallic gloss, in which the decorative layer contains a metal vapor-deposited layer or a metal thin film strip. Further, in order to keep the sharpness high, the average particle diameter of the inorganic filler is preferably 2 μm or less. Note that there is no particular inconvenience even when the particle size is reduced, so there is no need to provide a lower limit for the particle size to be used.

Since the supporting base material layer of the present invention has a three-layer structure, the layer A adjacent to the decorative layer does not contain an inorganic filler, or the amount of the inorganic filler is reduced to prevent curling of the laminated sheet for thermoforming. The addition of the inorganic filler necessary for this can be added to the other layers.
The thickness of the layer A is preferably 3 times or more than the average particle diameter of the inorganic filler used for the support base material layer, because it is less likely to affect the decorative layer, and more preferably 5 times or more thicker. preferable.

Note that the vividness mentioned here is an index for evaluating the appearance of the image of a fluorescent light by copying the fluorescent light on the object, and a good one is that the fluorescent light looks clear and unevenness is recognized. If the image looks distorted, it is judged that the sharpness is poor.

(Layer C)
In the support base material layer, the outermost layer C is different from the layer A, and since the decorative layer is not adjacent, an inorganic filler having a large particle diameter can be used. However, if the molding shrinkage ratio with the layer A is greatly different, the support base material itself tends to curl. Preferably, the difference in molding shrinkage between the layer A and the layer C is within 0.5%. Further, although depending on the resin composition constituting the layer A and the layer C and the kind of the inorganic filler to be added, the difference in the inorganic filler content between the two is 10% by mass or less, preferably 5% or less, and the same content rate. Most preferably.
When the thickness of the layer C is extremely different from the thickness of the layer A, the balance of the shrinkage force is lost and the support base material layer itself may be curled. Therefore, the difference in thickness is preferably 3 times or less, More preferably, it is 2 times or less.
(Layer B)
The layer B is a layer sandwiched between the layer A and the layer C. For this reason, the inorganic filler added to the layer B hardly affects the decorative layer even if the particle diameter is large. Further, even if the particle content is high, the supporting base material layer is not greatly curled. For this reason, it is preferable to add 40% or more of the inorganic filler contained in the support base material layer to the layer B and reduce the inorganic filler content in the layers A and C. It is preferable that the layer B contains 50% or more, more preferably 60% or more of the inorganic filler contained in the support base material layer. Furthermore, the aspect in which the layer B contains all of the inorganic filler contained in the support base material layer and the layer A and the layer C do not contain the inorganic filler is preferable.
(Lamination method of support base material layer)
As a method for laminating the supporting base material layer, a coextrusion molding method by heat melting is used because a molding sheet is low in cost and an efficient sheet with little thickness unevenness is obtained.
The extrusion conditions of the sheet used for the production of the support base material layer by the coextrusion molding method are not particularly limited as long as a multilayer sheet is formed. However, in the case of a polypropylene resin, the resin temperature is 180 to 250 ° C., which is a general condition. Then, the resin kneaded and melted by each extruder is laminated in a feed block which is a resin merging apparatus, and melt extrusion molding is performed by a T die.
Specifically, the shear rate in the feed block and the die forming the sheet forming portion is performed within a range of about 10 to 1,000 sec ⁻¹ , and the resin viscosity at that time is adjusted to 100 to 1 by adjusting temperature conditions and the like. , And molded at about 000 Pa. The melt-extruded sheet is cast to a predetermined thickness and cooled if necessary. When the target sheet is thick, a uniform sheet can be obtained by properly using a touch roll or an air knife, and when it is thin, electrostatic pinning.

(Inorganic filler)
When an inorganic filler is added to the resin of the supporting base layer, the molding shrinkage can be controlled to be small, and the difference in molding shrinkage between the supporting base layer and the thermoplastic film layer laminated thereon is reduced. Can do.

  However, if the particle size of the inorganic filler contained in the layer adjacent to the decorative layer in the multilayer structure of the supporting base layer is large, irregularities are generated on the surface of the supporting base layer, and the decorative layer laminated thereon Unevenness is affected. In particular, when the ink layer is a metal vapor deposition layer, the metallic luster is reduced due to the effect of unevenness. In addition, when the decoration layer is made of ink having a mirror-like metallic luster containing metal thin film strips, if the support base layer is uneven, the metal thin film strips are oriented substantially parallel to the support base layer. It becomes difficult to do so, and the orientation is disturbed. For this reason, the vividness of the metallic luster due to the metal thin film strips is impaired. Therefore, the support base material layer that is the base of the ink layer is required to have smoothness.

The kind of the inorganic filler used in the present invention is not particularly limited, and examples thereof include talc, calcium carbonate, clay, diatomaceous earth, mica, magnesium silicate, silica and the like.

(Colorant in the supporting base material layer)
It is preferable to add a colorant to the supporting base material layer because the concealability of the base color of the molded product becomes good. The colorant to be used is not particularly limited, and conventional inorganic pigments, organic pigments and dyes used for coloring general thermoplastic resins can be used according to the intended design. For example, inorganic pigments such as titanium oxide, titanium yellow, iron oxide, complex oxide pigments, ultramarine, cobalt blue, chromium oxide, bismuth vanadate, carbon black, zinc oxide, calcium carbonate, barium sulfate, silica, talc; azo Pigments, phthalocyanine pigments, quinacridone pigments, dioxazine pigments, anthraquinone pigments, isoindolinone pigments, isoindoline pigments, perylene pigments, perinone pigments, quinophthalone pigments, thioindigo pigments and diketopyrrolo Organic pigments such as pyrrole pigments; metal complex pigments and the like. In addition, it is preferable to use one or two dyes mainly selected from the group of oil-soluble dyes.

  The amount of colorant added to the support base layer varies depending on the type of colorant and the desired sheet thickness and color tone, but ensures the concealment of hue and background color and maintains impact strength. Therefore, the content is preferably in the range of 0.1 to 20% by mass, more preferably in the range of 0.5 to 15% by mass with respect to the resin constituting the colored layer. When the colorant is added in excess of 20% by mass, the impact strength is lowered, and when the amount of the colorant added is less than 0.1%, there is a tendency that the hiding property of the hue and the background color is not sufficient.

(Ink protective layer)
When an ink layer is used as a decorative layer of the laminated sheet for thermoforming of the present invention, heat resistance, solvent resistance, design properties, weather resistance, etc. are improved between the transparent or translucent thermoplastic film and the ink layer. For this purpose, one or more ink protective layers may be provided. The type of resin that can be used in the ink protective layer is not particularly limited as long as it does not impair the spreadability. However, acrylic resins are used from the viewpoints of easy adjustment of the crosslink density, weather resistance, adhesion to transparent thermoplastic film, etc. Resins are preferred. The crosslinking mechanism is not particularly limited, and in the case of acrylic resins, UV curing, EB curing, hydroxyl group-containing copolymer / isocyanate curing, silanol / water curing, epoxy / amine curing, etc. can be used. From the viewpoints of ease, weather resistance, reaction rate, presence or absence of reaction by-products, production cost, etc., hydroxyl group-containing copolymer / isocyanate curing is preferred.
The ink protective layer can be a colored layer in order to impart design properties. In this case, the amount of the colorant added varies depending on the type of the colorant, the target color tone and the thickness of the protective layer, but the total light transmittance of the protective layer is 20 so as not to conceal the ink layer having a specular metallic luster. % Or more, and the total light transmittance is more preferably 40% or more.

  As the colorant, a pigment is preferable. The pigment to be used is not particularly limited, and known and commonly used pigments such as colored pigments, metallic pigments, interference color pigments, fluorescent pigments, extender pigments and rust preventive pigments can be used.

  Examples of the color pigment include quinacridone series such as quinacridone red, azo series such as pigment red, phthalocyanine series organic pigments such as phthalocyanine blue, phthalocyanine green, and perylene red; and inorganic pigments such as titanium oxide and carbon black. Examples of the metallic pigment include aluminum powder, nickel powder, copper powder, brass powder, and chromium powder.

  Examples of the interference color pigment include pearl luster-like pearl mica powder and pearl luster-colored pearl mica powder. Examples of the fluorescent pigment include quinacridone, anthraquinone, perylene, perinone, and diketopyrrolopyrrole. , Isoindolinone, condensed azo, benzimidazolone, monoazo, insoluble azo, naphthol, flavanthrone, anthrapyrimidine, quinophthalone, pyranthrone, pyrazolone, thioindigo, anthanthrone, dioxazine , Organic pigments such as phthalocyanine and indanthrone, metal complexes such as nickel dioxin yellow and copper azomethine yellow, metal oxides such as titanium oxide, iron oxide and zinc oxide, barium sulfate and calcium carbonate Metal salt, carbon black, aluminum Inorganic pigments fine mica.

  Addition of plasticizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, lubricants, etc., to the thermoplastic resin sheet (C) containing the colorant, as long as the impact strength and moldability are not impaired. An additive may be blended, and these additives may be used alone or in combination of two or more.

(Laminated)
The ink layer and the supporting substrate layer are laminated via an adhesive layer, and as a bonding method, a dry lamination method using a conventional solvent-type adhesive, a wet lamination method, a hot melt lamination method, etc. are used to form a laminated sheet. I can do it.
Since the supporting base material layer of the laminated sheet for molding of the present invention has a small deformation such as its own curl due to the three-layer structure, the lamination does not become difficult due to the deformation in the present laminating process.

  Components constituting the adhesive include conventional phenol resin adhesives, resorcinol resin adhesives, phenol-resorcinol resin adhesives, epoxy resin adhesives, urea resin adhesives, polyurethane adhesives and polyaromatics. Type thermosetting resin adhesives, reactive adhesives using ethylene unsaturated carboxylic acid, etc., vinyl acetate resin, acrylic resin, ethylene vinyl acetate resin, polyvinyl alcohol, polyvinyl acetal, vinyl chloride, nylon and cyano Examples thereof include thermoplastic adhesives such as acrylate resins, rubber adhesives such as chloroprene adhesives, nitrile rubber adhesives, SBR adhesives, and natural rubber adhesives. In particular, an acrylic urethane adhesive is preferred because the adhesiveness between the acrylic resin and the polypropylene resin is good and the followability of elongation during vacuum forming is good.

  As a method for applying these adhesives, a gravure coater, a gravure reverse coater, a flexo coater, a blanket coater, a roll coater, a knife coater, an air knife coater, a kiss touch coater, a comma coater, or the like can be used.

The coating amount of the adhesive, the adhesive strength is sufficient, for drying also good, preferably in the range of 0.1 to 30 g / ^{m 2,} particularly preferably 2 to 10 g / ^{m 2.}
When it is less than 2 g / m ² , the adhesive strength is weakened, and when it is more than 10 g / m ² , the drying property is lowered. The thickness of the adhesive layer is preferably in the range of 0.1 to 30 μm, more preferably 1 to 20 μm, and particularly preferably 2 to 10 μm.

  In addition, for the purpose of improving the affinity with the adhesive, the adhesion surface of the support base material layer is a surface treatment such as plasma treatment, corona treatment, flame treatment, electron beam irradiation treatment, roughening treatment, ozone treatment, A dry plating process such as vacuum deposition, sputtering, or ion plating may be performed.

(Adhesive)
Moreover, it can replace with an adhesive bond layer and can also provide an adhesive layer. As the adhesive, acrylic, rubber, polyalkyl silicon, urethane, polyester, and the like are preferably used.

(Surface protective layer)
In the laminated sheet for molding of the present invention, performance such as designability, friction resistance, scratch resistance, weather resistance, stain resistance, water resistance, chemical resistance and heat resistance is imparted to the surface layer side during molding. In order to do so, one or more transparent, translucent or colored clear topcoat layers can be provided. As the topcoat agent, a lacquer type, a crosslinking type by isocyanate or epoxy, a UV crosslinking type or an EB crosslinking type is preferably used as long as the spreadability of the laminated sheet for molding is not inhibited.

(Sheet processing)
The thermoforming laminated sheet can be used as a surface layer in various molding methods. For example, after placing a transparent or translucent thermoplastic film on the opposite side of the mold and making it a preform with a three-dimensional shape by thermoforming, insert it into the female mold side in the injection mold. It can be molded by an insert injection molding method integrated with an injection resin.

(Thermoforming)
In order to use the laminated sheet for thermoforming for insert injection molding, it is necessary to form it in advance by thermoforming such as vacuum forming, pressure forming, vacuum pressure forming, etc. to form a preform.
Of these, vacuum forming is simple and preferable.

  The setting conditions for vacuum forming are not particularly limited, but when a far infrared heater is used, heating is performed at a heater temperature of 200 to 500 ° C. and an indirect heating time of about 5 to 30 seconds. Although it is necessary to decide while confirming the appearance and the degree of shrinkage, the cooling time by the mold is preferably 20 to 80 ° C. and 5 to 30 seconds.

  When hot plate pressure forming is performed, the hot plate temperature is a temperature at which the sheet to be formed can be shaped, for example, a storage elastic modulus (E ′) value obtained by dynamic viscoelasticity measurement determined by the JIS K7244-1 method is 100 MPa. A temperature of about 0.1 Mpa is preferred. Although the heating time by the hot plate varies depending on the thickness of the sheet, it is preferably 1 to 20 seconds, and the molding pressure is preferably 0.1 to 1 Mpa.

  Next, the obtained preform is placed in the mold so that the decorative layer is in contact with the female mold, and is integrally molded by injection molding a polypropylene-based thermoplastic resin on the back surface of the preform. . The resin temperature of the injection resin is not particularly limited, but is usually about 180 to 250 ° C. at which the polypropylene resin can be injected. The mold temperature is preferably about 20 to 80 ° C. for both the male mold and the female mold. However, when warping or the like occurs in the injection molded product, it is necessary to correct the temperature by adding a temperature gradient to the male mold and the female mold.

  Hereinafter, the present invention will be described with specific examples, but the present invention is not limited thereto. In addition, the physical-property evaluation in an Example and a comparative example was performed with the following measuring method or test method. In the examples, “part” and “%” are both based on mass.

(Vividness evaluation method)
In order to see the influence of the unevenness of the support base layer on the decorative layer in more detail, an ink layer having a mirror-like metallic luster is used as the decorative layer of the laminated sheet for thermoforming according to the present invention. The influence of the unevenness of the support base material layer on the decorative layer was observed.
The sharpness was evaluated based on the following criteria by recording a fluorescent lamp on the 250% extended portion of the bottom of the mold by the heat vacuum forming method. The mold used at this time (hereinafter referred to as mold 1) has a frontage of 156 × 127 mm, a bottom of 100 × 85 mm, and a depth of 60 mm. When the laminated sheet for molding of the present invention is molded, the surface magnification at the center of the bottom is It was about 250%. Here, the surface magnification is expressed as 250% when the entire area is 2.5 times the original area. Further, the same evaluation was performed on the sharpness after integral injection after the above-mentioned molded body was subjected to insert injection molding.
A: The image is clearly visible.
○: The image appears slightly blurred, but has sufficient sharpness.
X: Concavities and convexities are observed, and the image looks completely distorted.

(Curl evaluation method of support base material layer)
A sheet used for the support base layer was cut into 300 mm × 300 mm one day after the film formation, and the curl state was evaluated according to the following criteria.
◯: There is almost no curling, and when the curled side is placed on the ground so that the curled side is upward, the lift of the end is less than 20 mm and the plane state is maintained substantially.
Δ: Slightly curled, and when the curled side is placed on the ground so that the curled side is upward, the end is lifted by 20 mm or more.
X: Deformation is large, and when it is placed on the ground with the curled side facing up, it will be in a wound state of one or more turns.

(Method for evaluating deformability of molded products)
A trapezoidal mold (hereinafter referred to as mold 2) having a bottom surface of 120 × 90 mm, a top surface of 40 × 70 mm, and a height of 25 mm is placed at the center of a mold having a length of 170 × width of 140 × height of 30 mm, and then heated and vacuumed Molding was performed by a molding method, and a molded part formed by a mold was sandwiched and the deformability was evaluated according to the following criteria.
○: No deformation and maintaining the same shape as the mold.
Δ: Although there is local deformation, there is no problem in insert molding.
×: Large deformation, clearly different from the mold shape.

(Measurement method of molding shrinkage)
A convex mold (hereinafter, referred to as mold 3) in which a male mold having a length of 400 mm, a width of 30 mm, and a height of 5 mm is arranged in a metal center portion of length 500 mm × width 150 mm × height 30 mm is used. Then, the evaluation sheet was molded by a vacuum molding method, the distance T in the length direction of the mold side of the molded body was measured, and the molding shrinkage (%) was measured by the following formula.
Mold shrinkage (%) = (400−T) / 400 × 100

(Preparation of laminated sheet for thermoforming)
(1) Aluminum thin film strip nitrocellulose (HIG7) was dissolved in a mixed solvent of ethyl acetate: isopropyl alcohol = 6: 4 to obtain a 6% solution. The solution was applied onto a polyester film with a gravure plate having a screen line number of 175 lines / inch and a cell depth of 25 μm to form a release layer. After sufficiently drying, aluminum is vapor-deposited on the release layer to a thickness of 0.04 μm, and the same nitrocellulose solution as that used for the release layer is applied to the deposited film surface under the same conditions as in the release layer. The top coat layer was formed by coating.
The deposited film is immersed in a mixed solvent of ethyl acetate: isopropyl alcohol = 6: 4 to peel the aluminum deposited film from the polyester film, and then the aluminum deposited film is pulverized with a stirrer so that the size becomes about 150 μm. An aluminum thin film strip was prepared.

(2) Aluminum thin film strip slurry Aluminum thin film strip 10 parts Ethyl acetate 35 parts Methyl ethyl ketone 30 parts Isopropyl alcohol 30 parts The above mixture was mixed and stirred, and 5 parts of a nitrocellulose solution having the following composition was added.
Nitrocellulose (HIG 1/4) 25%
Ethyl acetate: isopropyl alcohol = 6: 4 mixed solvent 75%
While maintaining the temperature at 35 ° C. or lower, the above mixture is stirred using a turbo mixer until the size of the aluminum thin film pieces becomes 5 to 25 μm, thereby preparing an aluminum thin film piece slurry (nonvolatile content 10%). did.

(3) Surface protective layer and ink protective layer (hydroxyl group-containing copolymer)

  850 parts of butyl acetate and 1 part of perbutyl Z (trade name, manufactured by NOF Corporation, t-butyl peroxybenzoate) are added to a reaction vessel equipped with a temperature controller, a nitrogen introducing tube, a dropping device (2 units), and a stirring device. After charging and nitrogen substitution, the temperature was raised to 110 ° C. over 1.5 hours.

  Separately, 660 parts of methyl methacrylate, 150 parts of t-butyl methacrylate and 190 parts of 2-hydroxyethyl methacrylate (hereinafter referred to as monomer solution), 200 parts of isobutyl acetate, and perbutyl O (trade name, manufactured by NOF Corporation) , T-butyl peroxy-2-ethylhexanoate) and 2 parts of perbutyl Z (trade name, manufactured by NOF Corporation, t-butyl peroxybenzoate) are mixed well (hereinafter referred to as catalyst solution). Each was charged into a dropping device and immediately purged with nitrogen.

The above monomer solution and catalyst solution were dropped in a reaction vessel under a nitrogen atmosphere over 5 hours while monitoring the reaction temperature so as not to increase rapidly. As a result of continuing stirring for about 15 hours after the completion of dropping, a resin composition (O-1) having a solid content of 60% was obtained. The weight average molecular weight of the obtained resin was 100,000, the hydroxyl value of the solid content was 79 KOHmg / g, and Tg was 95 ° C.
Weight average molecular weight: Indicates a polystyrene equivalent value of the GPC measurement result.
Solid content: 1 g of a sample was taken in an aluminum dish, spread thinly and uniformly with toluene, air-dried, further dried in a hot air dryer at 108 ° C. for 1 hour, and calculated from the weight after drying.
The hydroxyl value was calculated from the monomer charge composition as the KOH neutralization amount, the polymer Tg was measured by DSC, and the acid value was measured by 0.05 mol · dm-3 potassium hydroxide-toluene solution titration method.

(Polyisocyanate compound)
“BURNOCK DN-981” (trade name, manufactured by Dainippon Ink & Chemicals, Inc., isocyanurate ring-containing polyisocyanate, number average molecular weight of about 1000, non-volatile content 75% (solvent: ethyl acetate), functional group number 3, NCO concentration 13 ~ 14%) is the polyisocyanate compound.
(Surface protective layer and ink protective layer)
The hydroxyl group-containing copolymer and the polyisocyanate compound were blended and mixed at a ratio of 1: 1 to prepare a solution for the surface protective layer and the ink protective layer.

(4) Ink (Ink preparation)
Aluminum thin film slurry (non-volatile content 10%) 30 parts Binder resin Carboxylic acid-containing PVC-vinyl acetate resin 3 parts
("Vinylite VMCH" manufactured by UCC)
Urethane resin
(Arakawa Chemical "Polyurethane 2593" nonvolatile content 32%) 8 parts Ethyl acetate 23 parts Methyl ethyl ketone 26 parts Isopropanol 10 parts The above was mixed to prepare an ink having a concentration of 35% by mass of aluminum thin film strips in the nonvolatile content.

(5) Adhesive Two-component polyester urethane adhesive (two-component mixed adhesive “ELX-1004” and “KR-90” manufactured by Dainippon Ink & Chemicals, Inc.) at a ratio of 8: 2. The adhesive was adjusted.

(6) Support base material layer The raw material for layer B which is the central layer of the support base material layer is 45 parts of Sumitomo Chemical's polypropylene resin (trade name "AD571") and 15 parts of Sumitomo Chemical's low density polyethylene (trade name). “F101-1”), 15 parts of ethylene propylene rubber (trade name “P-0480”) manufactured by Mitsui Chemicals, Inc., and further dried to 600 PPM or less by a hot air dryer. The master batch (containing 60% by mass of talc having an average particle size of 1.8 μm, 4.0 μm, or 8.0 μm) (hereinafter referred to as talc masterbatch X) has a content of talc shown in Table 1. In addition, it was prepared by stirring using a drum tumbler.

In addition, 60 parts of polypropylene resin (trade name “AD571”) manufactured by Sumitomo Chemical Co., Ltd. and 15 parts of low density polyethylene (trade name “F101-1” manufactured by Sumitomo Chemical Co., Ltd.) are used as the raw material for layer B, which is the central layer of the support base material layer. In addition, the talc master batch X was added so that the talc content was the content shown in Table 1, and stirred using a drum tumbler.

In addition, 50 parts of polypropylene resin (trade name “SPX7834”) manufactured by Sumitomo Chemical Co., Ltd. and 10 parts of low density polyethylene (trade name “F200-0” manufactured by Sumitomo Chemical Co., Ltd.) are used as the raw material for layer B, which is the central layer of the support base material layer. ), Resin B3 which is 15 parts of ethylene propylene rubber (trade name “P-0480”) manufactured by Mitsui Chemicals, Inc., and talc masterbatch X is added thereto, so that the talc content becomes the content shown in Table 1. In addition, a drum tumbler was used for stirring.

Also, the resin for layer A and layer C
Resin A1: Linear low density polyethylene resin (trade name “FV403”) manufactured by Sumitomo Chemical Co., Ltd.
Resin A2: Polypropylene resin (trade name “FS3611”) manufactured by Sumitomo Chemical Co., Ltd.
Resin A3: 65 parts of Sumitomo Chemical polypropylene resin (trade name “AD571”), 15 parts of low density polyethylene (trade name “F101-1”) manufactured by Sumitomo Chemical, 20 parts of ethylene propylene rubber (trade name) manufactured by Mitsui Chemicals, Inc. "P-0480"
A talc master batch X was added to the talc so that the talc content would be the content shown in Table 1, and stirred using a drum tumbler.

The raw material resins used for Layer A, Layer B and Layer C shown above are shown in Table 1, and after extrusion at 200 ° C. using two extruders, the ratio of the layer thickness is shown in Table 1 by a feed block. After being laminated and extruded from a T-die and passed through a cast roll heated to 40 ° C., the film was wound up, and a 150 μm thick film containing a predetermined average particle diameter and an added amount of talc shown in Table 1 was added. A stretched sheet was produced.

(7) Transparent or translucent thermoplastic film layer A rubber-modified PMMA film having a transparent surface gloss value of 150 (60 ° / 60 °) and a thickness of 125 μm was used as the transparent or translucent thermoplastic film layer. The molding shrinkage measured by the above-described molding shrinkage measuring method was 0.7%.

(7) Sheet lamination method A solution prepared for an ink protective layer and a surface protective layer is applied to a rubber-modified PMMA film using a micro gravure coater so as to have a dry film thickness of 2.0 μm and 10 μm, and then aging at 40 ° C. for 3 days. Processed. Next, the ink layer was coated on the ink protective layer to a dry film thickness of 2.0 μm using a gravure coater. Separately, the adhesive surface of the supporting base material layer was subjected to corona treatment, and the above adhesive was applied using a # 20 bar coater. After laminating the ink layer and the support base layer using a laminator set at 40 ° C., an aging treatment was performed at 50 ° C. for 3 days.
(8) Vacuum forming

  The resulting laminated sheet for thermoforming with glitter is indirectly heated from the surface protective layer side using a FE38PH small vacuum forming machine manufactured by Hermis Co., Ltd. A molded body was produced. The heating time was 3 seconds, the sheet temperature was 160 ° C. ± 3 ° C., the heater temperature was 370 ° C., the sheet-heater distance was 130 mm, the mold temperature was 40 ± 3 ° C., and the vacuum / cooling time was 8 seconds.

(9) Integrated injection molding The bottom of the molded body obtained with the mold 1 is brought into close contact so that the surface protective layer of the sheet having the ink layer is in contact with the female mold of the mold for injection molding at a mold temperature of 40 ° C. After heating, a molten resin made of Novatec PP resin (trade name “TX1868H5”) with a molding shrinkage ratio of 0.8% heated to 200 ° C. is injected into the mold and integrally molded to produce a clear image. An injection molded product having a laminated sheet excellent in the above was prepared. The injection molding machine is Sumitomo Nestal Injection Molding Machine Promat 80/40 from Sumitomo Heavy Industries, Ltd., and the mold is 65mm x 40mm x 3mm and 1.5mm (thickness is 3mm) that can take two-stage plate molded products. And 1.5 mm two-stage stepped plate).

(Examples 1-5, Comparative Examples 1-3)
The layer structure of the laminated sheet for thermoforming was as follows: surface protective layer / rubber-modified PMMA film layer / ink protective layer / ink layer / adhesive layer / support base layer, among which the support base layer was talc shown in Table 1. Sheeting was carried out before lamination in accordance with the method for preparing the supporting base material layer, with a 300 μm sheet having an addition rate and a layer structure. The obtained laminated sheet was formed into a molded body by the vacuum molding method using the mold 1, the mold 2 and the mold 3 under the above-mentioned conditions, and the sharpness and the deformability of the molded body were evaluated. Further, the bottom of the molded body obtained with the mold 1 was cut out, and the sharpness after integral injection was also evaluated in the same manner. Note that the molding shrinkage and curl of the support base material layer were evaluated before lamination.
The evaluation results are shown in Table 1.

As shown in Examples 1 to 5, a polyolefin resin layer (layer B) containing 5% to 60% of an inorganic filler, and a polyolefin resin layer containing 0 to 60% of an inorganic filler having an average particle diameter of 4 μm or less. Sheets sandwiched and laminated between (Layer A and Layer C) have a low molding shrinkage rate and do not curl themselves. Also, a thermoformed laminated sheet using this sheet as a supporting substrate layer is also used after vacuum forming. It can be seen that the molded body is hardly deformed. Also, it can be seen that both before injection molding and after injection molding have good sharpness.
On the other hand, as in Comparative Example 1, the support base material layer has a two-layer structure, and the support base material layer is not symmetrical in the thermoforming laminated sheet, the support base material layer itself is curled, resulting in poor workability. I understand that. In addition, in the thermoformed laminated sheet in which the inorganic filler (talc) having an average particle diameter of 8 μm was put in the surface layers (layer A and layer C), the deformation of the molded body could be suppressed, but the sharpness decreased (comparison) Example 2). Moreover, it turns out that the big deformation | transformation arises in the molded object after vacuum forming the laminated sheet for thermoforming using the support base material layer which does not put the inorganic filler like the comparative example 3. FIG.
By adopting a three-layer structure in which the support base material layer has a specific amount of inorganic filler such as talc added to the polyolefin resin layer, the mold shrinkage of the support base material layer is reduced while maintaining good moldability. It became possible to suppress deformation after thermoforming. By forming the supporting base material layer into a three-layer structure in which a thermoplastic resin layer added with a general inorganic filler is sandwiched between thermoplastic resin layers containing no inorganic filler or added with an inorganic filler having a small particle size, Improved the curl deformation of the support base layer during the production of laminated sheets, and when the decorative layer is a sheet with a mirror-like metallic luster, beautiful specularity without reducing the sharpness after thermoforming While maintaining the above, it is possible to provide molded articles for general use and insert molding.
In addition, the inorganic filler in the center layer can be used without selecting the particle size, so that the cost can be reduced, and a recycled material whose particle size is unknown can be used.

The laminated sheet for molding according to the present invention is useful as a laminated sheet having a mirror-like metallic luster with high image clarity that does not require exterior coating, and is used for applications such as automobile-related members, building material members, and home appliances.

Claims (10)

A laminated sheet for thermoforming in which a transparent or translucent thermoplastic film layer, a decorative layer and a supporting base material layer are laminated in this order, the supporting base material layer comprising a laminate of three polyolefin resin layers, The three layers are
1) a layer (layer A) adjacent to a decorative layer that does not contain an inorganic filler or has an average particle diameter of 4 μm or less;
2) a layer (layer C) in which the content of the inorganic filler is within ± 10% by mass with respect to the inorganic filler content of the layer A;
3) A laminated sheet for thermoforming which is a layer (layer B) sandwiched between layer A and layer C, and the total inorganic filler content of layers A, B and C is 5 to 60% by mass. 2. The laminated sheet for thermoforming according to claim 1, wherein a difference in molding shrinkage in the molding process between the thermoplastic film layer and the support base material layer is within 0.5%. The laminated sheet for thermoforming according to claim 1 or 2, wherein a difference in molding shrinkage between the layer A and the layer C is within 0.5%. Each layer of the said support base material layer is a layer which has a polypropylene resin as a main component, The laminated sheet for thermoforming in any one of Claims 1-3. The laminated sheet for thermoforming according to any one of claims 1 to 4, wherein the transparent or translucent thermoplastic film layer is a thermoplastic resin mainly composed of an acrylic resin. The laminated sheet for thermoforming according to any one of claims 1 to 5, wherein the decorative layer is a metal vapor-deposited layer or an ink layer having a mirror-like metallic luster. The laminated sheet for thermoforming according to claim 6, wherein the ink used for the ink layer having a mirror-like metallic luster is an ink containing metal thin film strips. The laminated sheet for thermoforming according to claim 1, wherein the inorganic filler is talc. The laminated sheet for thermoforming according to claim 1, wherein the support base material layer contains a rubber-like resin. The laminated sheet for thermoforming according to claim 1, wherein the decorative layer has a thickness of 5 μm or less.