JP2002240077A - Decorative sheet and method for simultaneous injection molding with decoration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve weatherability, while preventing whitening due to the bleeding of an ultraviolet absorbent, in addition to a feel of coating, a feel of transparency, etc., in simultaneous injection molding with decoration. SOLUTION: In a decorative sheet S, a transparent primer layer 2 containing an acrylic resin as a main component, the ultraviolet absorbent (a) such as benzotriazole, and a hindered amine light stabilizer such as a sebacate radical scavenger as a light stabilizer (b); a decorative layer 3 in which a binder resin contains a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a main component; and an adhesive layer 4 using a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer, etc.; are laminated on the back of a transparent base material sheet 1 containing an acrylic resin as a main component, no ultraviolet absorbent, and no light stabilizer (b). A desired decorative molding can be obtained by the simultaneous injection molding with decoration of the decorative sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative sheet of a laminate type having good weather resistance, and a method for simultaneous decoration by injection molding using the decorative sheet.

[0002]

2. Description of the Related Art Conventionally, decorative molded products obtained by decorating the surface of a resin molded product have been used for various purposes. For example, in the simultaneous injection molding decorating method disclosed in Japanese Patent Publication No. 50-19132 and the like, a decorative sheet is laminated and integrated on the surface of the resin molded product at the same time as the injection molding of the resin molded product, so that the decorative surface is decorated. A decorative molded product is obtained. When the decorative sheet is laminated on the surface of the resin molded product to obtain a decorative molded product by such a simultaneous injection molding decorative method, the transparent base sheet is used as the decorative sheet to decorate the base sheet. In the form of a surface layer in a molded article, by using a transparent resin sheet for the transparent substrate sheet, in addition to moldability, a protective function for a decorative layer provided on the back side of the transparent substrate sheet, a feeling of painting, It is possible to realize designability such as surface transparency.

Further, when weathering (light) resistance is required for a decorative molded product, an acrylic resin having better weathering resistance is used as a resin for the transparent substrate sheet, and an ultraviolet absorber is further used as a light stabilizer. It was common to add it to a transparent substrate sheet. For example, JP-A-8-183064 discloses that a transparent substrate sheet using an acrylic resin which itself has good weather resistance is employed, and that an ultraviolet absorber is further added thereto.

[0004]

However, when an ultraviolet absorber is added to a transparent substrate sheet, if the addition amount is small, sufficient weather resistance (light) may not be obtained.
Therefore, in order to sufficiently obtain the effect, it is necessary to increase the amount of addition. However, in this case, the ultraviolet absorber added to the transparent substrate sheet is heated by ink drying during printing of the decorative layer, etc., and heat during sheet heating and softening for preforming the decorative sheet injection molding die. Or bleed out on the surface of the transparent substrate sheet due to heat or the like during resin injection
It was inevitable to do it. The bleed-out ultraviolet absorbent causes problems such as whitening of the surface and a decrease in the effect of improving the weather resistance due to the outflow of the ultraviolet absorbent.

[0005] That is, an object of the present invention is to provide a decorative sheet and a simultaneous injection-molded sheet which improve the weather resistance while preventing the whitening due to the bleed-out of the ultraviolet absorbent and the deterioration of the weather resistance performance, as well as the design feeling such as the painting feeling and the transparency feeling. It is to provide a decoration method.

[0006]

In order to solve the above problems, a decorative sheet according to the present invention is a decorative sheet used for decorating simultaneously with injection molding, which comprises an acrylic resin as a main component and an ultraviolet absorber and an ultraviolet absorber. A transparent primer layer containing an acrylic resin as a main component and an ultraviolet absorber and a light stabilizer other than an ultraviolet absorber, a acrylic resin and vinyl chloride on the back surface of the transparent substrate sheet to which no light stabilizer other than the agent is added. −
The decorative layer and the adhesive layer each containing a mixture with a vinyl acetate copolymer as a main component of the binder resin were laminated in this order. Further, the decorative sheet of the present invention, as a preferred embodiment thereof, in the above configuration, wherein the ultraviolet absorber is a benzotriazole-based ultraviolet absorber, the light stabilizer is a sebacate-based radical scavenger, and the adhesive layer Has a composition mainly composed of a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer or an acrylic-modified polyolefin resin.

[0007] By adopting the above-described structure, the acrylic resin is used for the transparent substrate sheet as a basic performance. Design can be imparted. Further, an ultraviolet absorber and a light stabilizer other than the ultraviolet absorber (the ultraviolet absorber is also a kind of light stabilizer in a broad sense, but is hereinafter referred to as an ultraviolet absorber in the present invention) Light stabilizer other than the agent is simply referred to as "light stabilizer"), so it is necessary to print the decorative layer, use the decorative sheet (when preforming or injecting resin), etc. Even if the ultraviolet absorbent and the light stabilizer bleed from the transparent primer layer due to heat, the transparent base material sheet is thicker than the transparent primer layer (normally about 10 to 100 times), and the decorative layer (normally 2 to 10 times) Bleeding is prevented. Therefore, the decorative layer and the adhesive layer, which are to be protected from sunlight on the back side of the transparent primer layer, are protected from ultraviolet rays of sunlight by the ultraviolet absorbent purple remaining immediately above. In addition, the acrylic resin of the transparent substrate sheet itself has good weather (light) resistance, and the weather resistance is further reinforced to some extent by an ultraviolet absorber and a light stabilizer which bleed from the transparent primer layer and entered. . Therefore, a sufficient effect can be obtained as weather resistance. Moreover, even if the ultraviolet absorbers and light stabilizers bleed out in the transparent substrate sheet, the amount is small in that they are not originally added to the transparent substrate sheet,
It does not reach the point where the decorative sheet surface bleeds out and whitens. Furthermore, even if the ultraviolet absorber and the light stabilizer bleed out to the decoration layer side, they are trapped by the adhesive layer and do not contribute to whitening of the surface. Furthermore, in the embodiment in which the specific material is used for each of the ultraviolet absorber, the light stabilizer and the adhesive layer as described above, good weather resistance is reliably obtained and the interlayer adhesion in the decorative sheet layer is ensured. When the injection resin is a general-purpose resin such as ABS (acrylonitrile-butadiene-styrene copolymer) resin, styrene resin, acrylic resin, vinyl chloride resin, or polyolefin resin. It is a decorative sheet in which the adhesion between the resin and the resin molded product can be reliably obtained.

[0008] The injection molding simultaneous decorating method of the present invention comprises:
After inserting the decorative sheet of the present invention having any one of the above configurations between the male and female molds in a direction in which the adhesive layer is in contact with the injection resin, the molds are clamped to form a cavity formed by the molds. After injecting the resin in the fluid state and solidifying the resin,
The mold was opened to obtain a decorative molded product in which the decorative sheet was laminated and integrated with the resin molded product.

By adopting such a decorating method, the effect of the decorating sheet described above can be obtained. In other words, in addition to the surface coating feeling by the transparent base sheet, the design imparting of transparency and the like, and the basic weather resistance, in addition, the ultraviolet absorber and the light stabilizer bleed out to the surface by the heat at the time of using the decorative sheet. Better weatherability can be imparted to the decorative molded product while preventing whitening. Furthermore, by using the decorative sheet of the specific material, each of the ultraviolet absorber, the light stabilizer, and the adhesive layer, good weather resistance can be reliably imparted to the decorative molded product, and the decorative sheet layer has Adhesion between layers is surely obtained, and ABS is added to the injection resin.
When a general-purpose resin such as a resin, a styrene resin, an acrylic resin, or a vinyl chloride resin is used, the adhesion between the decorative sheet and the resin molded product can be reliably imparted to the decorative molded product.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

Decorative sheet: First, the decorative sheet will be described.

[Outline] FIG. 1 is a sectional view showing an example of a decorative sheet according to the present invention. The decorative sheet S shown in FIG. 1 is a decorative sheet used for simultaneous decorating with injection molding. The decorative sheet S is composed of an acrylic resin as a main component and an ultraviolet absorber a and a light stabilizer b. A transparent primer layer 2 containing a resin as a main component and an ultraviolet absorber a and a light stabilizer b added thereto, a decoration layer 3 containing a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a main component of a binder resin, The decorative sheet has a configuration in which the adhesive layer 4 is laminated in this order. In addition, a benzotriazole type is used as the ultraviolet absorber, a hindered amine type light stabilizer, especially a sebacate type radical scavenger is used as the light stabilizer, and an acrylic resin and vinyl chloride-acetic acid are used for the adhesive layer. A configuration using a mixture with a vinyl copolymer or an acrylic-modified polyolefin-based resin as a main component is a preferable embodiment of the above-described configuration, in which good weather resistance is reliably obtained and adhesion in the decorative sheet layer is achieved. In addition, when the injection resin is a general-purpose resin such as ABS resin, styrene resin, acrylic resin, vinyl chloride resin, or polyolefin resin, the decorative resin has good adhesion to these resins. Become.

[Transparent Substrate Sheet] The transparent substrate sheet 1 is made of a thermoplastic resin having moldability, such as vinyl chloride resin, acrylic resin, styrene resin, polycarbonate resin, polyester resin, or polyolefin such as polypropylene or polyethylene. Although a resin or the like can be used, in the present invention, an acrylic resin having excellent weather resistance is used. In addition, since acrylic resin is also excellent in transparency, it is also suitable for imparting design properties such as painting feeling and surface transparency, and is also preferable in that it can impart a high-grade feeling to decorative molded products.

Examples of the acrylic resin include polymethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, and methyl (meth) acrylate-styrene copolymer. Acrylic resin (however, (meth) acrylate means acrylate or methacrylate) is used alone or as a mixture of two or more. The resin of the transparent substrate sheet is mainly composed of an acrylic resin, but if necessary, a resin other than the acrylic resin may be added as an auxiliary component resin. Examples of the auxiliary component resin include a fluorine resin such as polyvinylidene fluoride.

The transparency of the transparent substrate sheet may be colorless and transparent in addition to colorless and transparent. Also, in the transparent substrate sheet,
If necessary, various additives such as a plasticizer, a stabilizer, and a coloring agent may be appropriately added for adjusting physical properties. However, in the present invention, the ultraviolet absorber and the light stabilizer are contained in the transparent substrate sheet. Not added to In addition, the transparent substrate sheet is a single-layer sheet,
It may be a sheet of a laminate having more than two layers. The thickness of the transparent substrate sheet (total thickness in the case of a laminate sheet) is not particularly limited, but is generally about 20 to 500 μm.

[Transparent primer layer] Transparent primer layer 2
Is a layer for the purpose of easy adhesion intended to improve the adhesion between the base sheet and the decorative layer. In the present invention, this layer is mainly composed of an acrylic resin having excellent weather resistance, and further has an ultraviolet ray. It is provided as a layer for further adding weather resistance by adding an absorber and a light stabilizer.

The acrylic resin in the transparent primer layer is appropriately selected from the same ones listed for the transparent substrate sheet, and methyl (meth)
One or more monomers such as acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and octyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl ( An acrylic polyol obtained by copolymerizing a (meth) acrylate having a hydroxyl group in a molecule such as (meth) acrylate can also be used.

Examples of the ultraviolet absorber include, for example, organic compounds such as 2- (2′-hydroxy-3 ′,
5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-t
tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-
tert-amyl-5'-isobutylphenyl) -5
Chlorobenzotriazole, 2- (2'-hydroxy-
3'-isobutyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 '
-Isobutyl-5'-propylphenyl) -5'-hydroxyphenyl-5 such as 5-chlorobenzotriazole
-Chlorobenzotriazole-based ultraviolet absorbers, 2-
2′-hydroxyphenylbenzotriazole-based ultraviolet absorption such as (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole and 2- (2′-hydroxy-5′-methylphenyl) benzotriazole Benzotriazole UV absorbers such as agents,
2,2'-dihydroxybenzophenones such as 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and 2,2 ', 4,4'-tetrahydroxybenzophenone UV absorbers, 2-hydroxybenzophenone-based UV absorbers such as 2-hydroxy-4-methoxybenzophenone and 2,4-dihydroxybenzophenone,
Salicylate-based ultraviolet absorbers such as phenyl salicylate and 4-t-butyl-phenyl-salicylate;
Cyanoacrylate ultraviolet absorbers such as -ethyl-hexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3,3-diphenylacrylate, octyl-2-cyano-3,3-diphenylacrylate Etc. can be used. As the inorganic compound, ultraviolet absorbers of inorganic oxides such as zinc oxide, iron oxide, titanium oxide, and cerium oxide having a particle size of 1 μm or less, and more preferably 0.2 μm or less in terms of visible light transparency. Etc. can be used.

It should be noted that the inorganic oxide-based ultraviolet absorber does not deteriorate with respect to light or heat, and thus maintains the ultraviolet absorption ability for a long period of time. In addition, unlike organic UV absorbers and light stabilizers, performance degradation can be prevented without bleeding.

These inorganic oxides are preferably used in the form of fine powder having a particle size of 1 μm or less. In particular, the inorganic oxide has sufficient transparency to visible light so that the decorative layer below the transparent primer layer can be seen through. 1 / of the wavelength of visible light
2 or less, ie, 200 nm or less, more preferably 10 nm or less.
It is preferable to use those having a thickness of 0 nm or less, particularly preferably in the range of 8 to 30 nm. By using such a fine powder, even if the inorganic oxide is contained in a relatively large amount, it is possible to give the decorative layer an excellent ultraviolet absorbing ability so that the pattern of the decorative layer is not clouded, without impairing the transmittance of visible light. it can.

In the above inorganic oxide type fine powder, when a vinyl chloride-vinyl acetate copolymer is used as a resin for the transparent primer layer, especially as an auxiliary resin in addition to the acrylic resin, the light irradiation Cerium oxide is the best in terms of the effect of preventing discoloration, zinc oxide is second, and titanium oxide is second.

When cerium oxide is used as the inorganic oxide, the cerium oxide to be added to the ink or paint may be in the form of a simple powder, but especially when it is a fine powder having a particle size of 200 nm or less, it may be converted into a liquid. Is difficult to uniformly disperse, and secondary agglomeration is likely to occur. Therefore, a known easily dispersible surface treatment for obtaining good dispersibility may be performed, or
As described in JP-A-306435, it is preferable to use a sol or sol powder in a state of being added to a paint or ink.

It is preferable to use a powder of such cerium oxide in a crystalline state. The reason is that in the case of amorphous, due to changes in heat and pressure during decoration sheet production and simultaneous decoration during injection molding, exposure to sunlight when using decorative molded products, repeated cold heat outdoors, etc. This is because crystallization may proceed to a lower degree and the transparency of the transparent primer layer may change. In addition, cerium oxide includes cerous oxide and ceric oxide, but ceric oxide is more preferable because it has the instability of being gradually oxidized to ceric oxide.

It is also possible to use a mixture of cerium oxide and iron oxide or titanium oxide as an inorganic ultraviolet absorber.

The amount of the ultraviolet absorbent of an organic compound such as a benzotriazole compound is in the range of 0.1 to 2% by mass, more preferably 0.5% by mass or more, based on the total amount of the resin to be added. Is preferred. If it is less than 0.1% by mass, sufficient weather resistance cannot be obtained, and if it exceeds 2% by mass, the cost becomes high, and it may be difficult to completely prevent whitening when exposed to outdoor sunlight.

The amount of the inorganic ultraviolet absorber such as cerium oxide fine powder added is 0.1 to the total amount of the added resin.
The range of 2 to 2% by mass is preferred. Fine particle size of 200n
If the molecular weight is less than m, transparency to visible light can be ensured, so that a blending of up to 1% by mass is possible. If the content is less than 0.1% by mass, a sufficient ultraviolet absorbing effect cannot be obtained, and if it exceeds 2% by mass, the layer tends to become brittle, and the physical properties such as the decrease in moldability and the adhesion to other layers. Is undesirably reduced.

In order to further improve the weather resistance,
It is preferable to add a light stabilizer other than the ultraviolet absorber.
Examples of the light stabilizer include a nickel-based ultraviolet light stabilizer and the like, and typically, a hindered amine-based light stabilizer is preferably added. As hindered amine light stabilizers, bis-
Sebacate radical scavengers such as (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis- (N-methyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate; Dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-
Tetramethyl-4-piperidine condensates and other compounds disclosed in, for example, Japanese Patent Publication No. 4-82625 are used.

The content of the light stabilizer is in the range of 0.1 to 2% by mass relative to the whole resin, more preferably 0.1 to 2% by mass.
It is preferable that the content be 5% by mass or more. If the amount is less than this, the effect of improving the weather resistance cannot be obtained, and if it is more than this, the cost increases.

In the combination of the above-mentioned ultraviolet absorber and this light stabilizer, in particular, from the viewpoint of compatibility between weather resistance and moldability, a benzotriazole-based ultraviolet absorber and a hindered amine-based light stabilizer are used. Combinations using sebacate radical scavengers are preferred. In addition, the addition amount of the benzotriazole-based ultraviolet absorber in combination is 0.1.
It is preferable that the amount is 5% by mass to 2% by mass and the sebacate radical scavenger as the light stabilizer is 0.5% by mass to 2% by mass. The sebacate radical scavenger is a light stabilizer having a low molecular weight, which is easily available among hindered amine light stabilizers. In the present invention, even if such a low molecular weight compound is used, the bleed-out of the compound can be prevented. Is added to the transparent primer layer so that the adverse effect of the light stabilizer does not occur, so that the effect of improving the weather resistance by the light stabilizer can be efficiently obtained.

Here, as an example of the benzotriazole-based ultraviolet absorber, 2- (2'-hydroxy-3'-R-
5′-R ′) phenylbenzotriazole [provided that R,
R ′ is an alkyl group or the like] having the following structural formula I, and bis- (NR-2,2,6,6-tetramethyl-4- as a sebacate radical scavenger among the hindered amine light stabilizers. The structural formula of piperidyl) sebacate (where R is an alkyl group or the like) is represented by the following formula II.

[0031]

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[0032]

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The transparent primer layer is formed by a known printing method such as gravure printing or roll coating or a coating method using an ink or a coating solution containing the above-mentioned acrylic resin, ultraviolet absorber and light stabilizer. It may be formed.

[Decoration Layer] The decoration layer 3 is basically not particularly limited except that the binder resin is made of a specific resin. The decorative layer is usually a printing ink or paint,
It is formed by a known printing or coating method. A typical example of the decorative layer is a pattern layer expressing a pattern.

In the present invention, the binder resin is mainly composed of a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer. Here, as the acrylic resin, besides appropriately selecting from the same ones listed in the above-mentioned transparent substrate sheet, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, etc. An acrylic polyol obtained by copolymerizing a (meth) acrylate having a hydroxyl group in a molecule such as 2-hydroxyethyl (meth) acrylate can also be used. Further, as the vinyl chloride-vinyl acetate copolymer, the vinyl acetate content is usually 5 to 20.
Those having a mass percentage of about 350 and an average degree of polymerization of about 350 to 900 are used. The mixing ratio of the acrylic resin and the vinyl chloride-vinyl acetate copolymer is about 1/9 to 9/1 (mass ratio) of the acrylic resin / vinyl chloride-vinyl acetate copolymer.
In addition, if necessary, other resins such as thermoplastic polyester resin, thermoplastic urethane resin, or resin such as chlorinated polyolefin such as chlorinated polyethylene and chlorinated polypropylene may be used in combination as a sub-component resin. You may.

The coloring agent used for the printing ink (or paint) may be a known dye or pigment, for example, titanium white, zinc white, carbon black, iron black, red iron oxide, chrome vermillion, graphite, titanium Yellow, ultramarine, inorganic pigments such as cobalt blue, phthalocyanine blue, indathrene blue, isoindolinone yellow, benzidine yellow, quinacridone red, polyazo red, aniline black and other organic pigments (or dyes), or
Metal pigments composed of flaky foil powders of aluminum, brass, etc., pearlescent pigments composed of flaky foil powders of titanium dioxide coated mica, basic lead carbonate, etc. are used.

The pattern of the decorative layer may be, for example, one or two or more types of wood grain, stone grain, cloth grain, sand grain, squeezed pattern, tiled pattern, brickwork pattern, geometric pattern, character, symbol, and full surface solid. Is used.

The decorative layer may be a layer for imparting a function such as a conductor layer or a magnetic layer, in addition to a layer for expressing a pattern such as a grain pattern. That is, the decoration in the present invention also includes imparting functionality. For example, in the conductor layer, a conductive powder such as silver powder is dispersed as a material to be contained in the specific binder resin instead of the coloring agent. In the case of a magnetic layer, a magnetic powder made of iron oxide or the like is dispersed instead of the coloring agent. Further, as the pattern of the decorative layer, as a pattern pattern that is not visible, for example, a pattern printed with a fluorescent ink that is transparent to visible light and emits fluorescence by ultraviolet irradiation, a bar code printed with an infrared absorbing ink, or the like. good.

As the layer for imparting functionality, other than the decorative layer specific to the present invention, a hard coating layer, an anti-fog coating layer, etc., which are provided exclusively on the surface of the base sheet, may be used. You may use together with a layer.

[Adhesive Layer] As the adhesive layer 4, for example, a known resin such as a thermoplastic resin or a thermosetting resin as a heat-sensitive adhesive may be used in accordance with the resin of the resin molded article to be adhered. Used. As the thermoplastic resin, for example, one kind of acrylic resin, chlorinated polyolefin resin, vinyl chloride-vinyl acetate copolymer, acrylic-modified polyolefin resin, thermoplastic urethane resin, thermoplastic polyester resin, polyamide resin, rubber resin, etc. Alternatively, a mixture of two or more kinds is used. As the thermosetting resin, a urethane resin, an epoxy resin, or the like is used.

Among them, in the present invention, as a preferred form of the adhesive layer, a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer or an acrylic-modified polyolefin resin is used as a main component.

By using a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer for the adhesive layer, particularly when the injection resin is an ABS resin, an acrylic resin or a vinyl chloride resin, the decorative sheet and the resin are particularly good. Adhesion with the molded product is obtained. In addition, it is needless to say that close contact with an injection resin other than these is possible. When the resin of the adhesive layer is a mixture of the specific resin as a main component, a resin other than the specific resin may be used in combination as a sub-component.

Further, by using an acrylic-modified polyolefin resin for the adhesive layer, when the injection resin is a polyolefin resin, it has more sufficient heat resistance than when chlorinated polypropylene is used. Product). Therefore, the decorative molded article using the polyolefin resin can be applied to applications requiring heat resistance, such as automobile interior parts. In addition, the heat resistance of the adhesiveness is obtained especially for a resin molded product of a polyolefin resin, which generally has poor adhesion.

The acrylic-modified polyolefin resin is not particularly limited as long as it is a resin obtained by modifying a polyolefin resin with an acrylic monomer (or a prepolymer as a polymer of the monomer). However, preferably, at least a resin obtained by graft-polymerizing an acrylic monomer or / and a prepolymer onto the main chain of polypropylene is one of the preferable resins in view of heat resistance of adhesion and suitability for coating and printing. It is. In order to adjust physical properties such as improvement of heat resistance, a non-acrylic monomer or preppolymer may be further graft-polymerized, or a chlorine atom may be added as long as the heat resistance of adhesiveness is not reduced.

The polyolefin resin component of the acrylic-modified polyolefin resin includes, for example, polypropylene, polyethylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, ethylene-propylene-hexene Copolymers and the like.

The acrylic monomers that modify the polyolefin resin include methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic acid.
n-propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, octyl (meth) acrylate, ethylhexyl (meth) acrylate, (meth) acrylic acid-2- Hydroxyethyl, (meth) acrylic acid-2-hydroxy-3
-Alkyl (meth) acrylate monomers such as phenoxypropyl. In addition, as the acrylic prepolymer, the above acrylic monomers, or these monomers and other monomers (for example, styrene and the like)
And the like.

In order to obtain the above-mentioned acrylic-modified polyolefin-based resin, for example, the polyolefin-based resin is dissolved or swollen with a suitable solvent, and then an acrylic-based monomer or an acrylic-based resin is added together with a radical polymerization initiator. A prepolymer may be added and the monomer or prepolymer may be graft-polymerized to the main chain of the polyolefin resin. As the solvent, for example, hydrocarbon, chlorobenzene, anisole, cyclohexane, naphtha and the like are used.As the radical polymerization initiator, benzoyl peroxide, di-t-butyl peroxide, azobisisobutyronitrile and the like are used. May be used.

The adhesive layer is formed of the above resin adhesive by a known printing or coating method such as gravure printing or roll coating. The thickness of the adhesive layer is not particularly limited, but is usually about 1 to 100 μm. In the adhesive layer, various physical properties such as suitability for printing (or coating) are further adjusted.
For the purpose of improvement, various known additives such as extenders and storage stabilizers may be appropriately added as necessary. The acryl-modified polyolefin resin can be used as a coating liquid or ink by dissolving it in an organic solvent by modifying the polyolefin resin with acryl. To form an adhesive layer. In this case, the adhesive layer may be formed by laminating a film formed as a resin sheet by a T-die extrusion method or the like by a dry lamination method using an adhesive such as a two-component curable urethane resin.

Injection molding simultaneous decorating method: In the injection molding simultaneous decorating method of the present invention, the decorative sheet of the present invention is used to decorate the surface of a resin molded product by the so-called injection molding simultaneous decorating method. In this method, the decorative sheet is laminated and integrated with the surface of the resin molded product by forming the sheet and laminating the decorative sheet so that the adhesive layer is in contact with the resin molded product.

As described in JP-B-50-19132, JP-B-43-27488, etc., a decorative sheet is inserted between the male and female molds as described in JP-B-50-19132 and JP-B-43-27488. The molds are clamped, the resin in the fluid state is injected into the cavity formed by both molds and solidified, and simultaneously with the molding of the resin molded product, a decorative sheet is laminated and integrated on the surface to form a decorative molded product. How to get.

The simultaneous decorating method for injection molding of the present invention can take various forms in the conventionally known simultaneous decorating method for injection molding, except that the above-described decorative sheet of the present invention is used as the decorative sheet to be used. Things. For example, basically, in a mode in which the decorative sheet is preformed or not,
Either is acceptable. Further, the decorative sheet may or may not be preheated. Note that the decorative sheet is usually preheated at the time of preforming.

Of course, when the decorative sheet has a large drawing, it is preferable to perform preforming. On the other hand, when the decorative sheet is not narrowed down, the decorative sheet may be formed by the resin pressure of the resin in the flowing state to be injected. At this time, if the drawing is shallow, the decorative sheet may be formed only by the resin pressure of the resin in the flowing state to be filled in the mold at the same time as the resin injection without preforming. Further, even when the decorative sheet is formed by resin pressure, the decorative sheet may utilize the heat of the injection resin without preheating. In addition, the pre-molding of the decorative sheet is usually performed by using the injection mold also as the vacuum mold, but before supplying the decorative sheet between the molds, the decorative mold is decorated with another vacuum mold outside the mold. Preforming such as vacuum forming of a sheet (offline preforming) may be used. However, the preforming is preferably performed by using both the injection molding die and the vacuum molding die in that the decorative sheet can be efficiently and accurately laminated. However, in the case where the preformed decorative sheets are collectively manufactured in another place in advance, the preforming is preferably in the form of off-line preforming. In the description of the present invention, vacuum forming includes vacuum pressure forming.

Here, the injection molding simultaneous decorating method will be described for each step as an example of a form in which a decorative sheet is preformed by using an injection mold also as a vacuum mold, for example. There is an injection molding simultaneous decorating method including the following steps. That is, a sheet supplying step of supplying a decorative sheet on the female parting surface when the pair of male and female molds is in the mold open state, and a clamping step of fixing and holding the decorative sheet on the female parting surface. A stretching step (preliminary molding step) of stretching the decorative sheet along the cavity surface of the female mold, a mold clamping step of clamping the female mold and the male mold, and forming the female mold and the male mold. An injection step of injecting and filling a resin in a flowing state into a cavity to be solidified, solidifying and laminating a resin molded product and the decorative sheet, a mold opening step of separating a female mold and a male mold, There is an injection molding simultaneous decorating method in which a take-out step of taking out a decorated molded product in which a molded product is decorated with a decorating sheet is performed in this order.

FIG. 2 is a conceptual view for explaining the injection molding simultaneous decorating method in one embodiment. In the embodiment shown in FIG. 2, before the mold is clamped, the decorative sheet is heated and softened between the molds, preliminarily molded by vacuum molding using an injection mold, and then the resin is injected by clamping. Then, FIG.
The method of simultaneous decoration by injection molding will be described more specifically with reference to FIG. This form is more preferable when the decorative sheet is deeply drawn out of the various combinations of the preforming and preheating of the decorative sheet. The decorative sheet used in the simultaneous injection molding and decorating method of the present invention is a single sheet,
It goes without saying that either of continuous belts may be used.

First, as shown in FIG. 2A, as an injection mold, a mold Ma having a runner and a gate (gate) communicating with the injection nozzle, and a suction hole 4 in the cavity surface.
A pair of molds Mb having the number 1 and also serving as a sheet preform is used. These molds are made of metal such as iron or ceramics. Both molds Ma and Mb in the mold open state
The decorative sheet S is supplied in between, and the decorative sheet S is fixed to the mold Mb by pressing it with a sheet clamp 42 having a frame shape in plan view. At this time, it goes without saying that the adhesive layer side of the decorative sheet faces the injection resin side on the right side of the drawing. Then
The decorative sheet is appropriately heated and softened by a heater (not shown) inserted between both molds. The heating is, for example, non-contact radiation heating, but may be conduction heating by contact. Then, the decorative sheet is sucked through the suction hole and vacuum formed, and the decorative sheet is preformed along the cavity surface of the mold Mb. Next, the heater is retracted from between the two dies, the two dies are clamped as shown in FIG. 2B, and a cavity formed by the two dies is filled with a resin in a flowing state such as a heated and molten state. After the resin is solidified by cooling or the like, the mold is opened and the molded product is taken out. Then, if there is an unnecessary portion of the decorative sheet, trimming is appropriately performed to obtain a decorative molded product having a configuration in which the decorative sheet is laminated and integrated on the surface of the resin molded product.

[Injection Resin] In the simultaneous decorating method for injection molding of the present invention, the resin to be injection-molded is not particularly limited and may be a known resin. What is necessary is just to select according to the required physical properties of a product, cost, etc. For example, if it is a thermoplastic resin, polyethylene, polypropylene, polybutene,
Polymethylpentene, ethylene-propylene copolymer,
Examples include polyolefin resins such as ethylene-propylene-butene copolymer and olefin-based thermoplastic elastomer, or ABS resin, styrene resin, acrylic resin, vinyl chloride resin, and polycarbonate resin. In the case of a curable resin, it is a two-liquid curable resin, for example, an uncured resin liquid such as a urethane resin, an unsaturated polyester resin, or an epoxy resin. The thermoplastic resin is melted by heating and injected in a fluid state, and the curable resin (the uncured product) is injected in a flowing state at room temperature or appropriately heated. However, in the simultaneous injection molding decorating method of the present invention, the above-described decorative sheet of the present invention is used, and as a preferred mode in the decorative sheet of the present invention, an acrylic resin and a chloride In a form using a mixture with vinyl-vinyl acetate copolymer as a main component, the most effective taking advantage of its characteristics is, among the above, ABS resin, styrene resin,
Acrylic resin, vinyl chloride resin and the like. Further, in a mode in which an acrylic-modified polyolefin-based resin is used as a main component as the adhesive layer, a polyolefin-based resin is preferred in that it exhibits an effect by utilizing its features.

As the injection resin, a resin colored by adding a coloring agent may be used as appropriate according to the intended use. As the coloring agent, a known coloring agent as described above for the decorative layer may be used. In addition, the injection resin may contain, if necessary, various known additives such as silica, alumina, talc, calcium carbonate, inorganic powders such as aluminum hydroxide, fillers such as glass fibers, stabilizers, lubricants, and elastomers. To be included.

[0058]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples.

Example 1 A decorative sheet S having the structure shown in FIG. 1A was manufactured as follows. With a thickness of 125 μm,
An acrylic resin sheet made of polymethyl methacrylate (glass transition temperature: 105 ° C.) containing neither an ultraviolet absorber nor a light stabilizer was used as a transparent base sheet 1, and a 4 μm-thick transparent primer layer was sequentially formed on the back side. 2 (based on the main resin of the acrylic resin, 0.8% by mass of a benzotriazole-based ultraviolet absorber and 0.8% by mass of a sebacate-based radical scavenger as a hindered amine-based light stabilizer,
3 μm thick decorative layer (a mixture of acrylic resin and vinyl chloride-vinyl acetate copolymer at a ratio of 8 to 2 by mass is used as a binder resin, and titanium white, red stalk, graphite and ultramarine are colored. A three-color marble pattern was overprinted with the ink used as an agent, and a solid layer was further overprinted thereon.) A 6-μm-thick adhesive layer (acrylic resin and vinyl chloride-vinyl acetate copolymer) A layer composed of a mixture having a mass ratio of 1: 1 with the union was formed by a normal gravure printing method to obtain a decorative sheet.

The decorative sheet is laminated on the surface of the resin molded article simultaneously with the molding of the resin molded article by the simultaneous injection molding and decorating method of the present invention as shown in the conceptual diagram of FIG. A decorative molded product having the surface of the molded product decorated was obtained. The molded product to be decorated was a vehicle interior panel having a width of 40 mm, a length of 400 mm, and a thickness of 3 mm. And the injection molding simultaneous decorating method, the female mold of injection molding was used as a vacuum mold, and after inserting the decorative sheet between the male and female molds, the sheet was heated to a sheet temperature of 110 ° C. with an infrared radiation heating type heater and softened. Then, vacuum suction is performed through the groove-shaped suction holes provided in the female mold so that the decorative sheet is oriented toward the male mold so that the adhesive layer side (relative to the base sheet) is in contact with the injection resin. And preformed according to the shape of the female mold cavity.

Thereafter, the injection resin temperature is 240 ° C., the mold temperature is 7
Under the condition of 0 ° C., brown heat-resistant ABS resin (heat-resistant temperature 95
C) was injected from a male gate, and the decorative sheet and the resin molded product were laminated and integrated to form a decorative molded product.

Example 2 An acrylic-modified polyolefin obtained by graft-polymerizing an adhesive layer as in Example 1 by graft-polymerizing an alkyl methacrylate-based acrylic component to the main chain of a polymer comprising a polypropylene-based olefin component. A decorative sheet was prepared in the same manner as in Example 1 except that the thickness of the base resin was changed to 6 μm. Next, the injection resin temperature is 230 ° C.
At a mold temperature of 50 ° C., 10 parts by mass of ethylene-propylene rubber and 20 parts by mass of talc powder were added to 100 parts by mass of polypropylene.
A decorative molded article was formed in the same manner as in Example 1, except that a polyolefin-based resin to which parts by mass were added was injected.

Comparative Example 1 A decorative sheet was produced in the same manner as in Example 1 except that the ultraviolet absorbent and the light stabilizer in the transparent primer layer were not added. Then, a decorative molded product was produced in the same manner as in Example 1.

[Comparative Example 2] In Example 1, the ultraviolet absorbent and the light stabilizer were removed from the transparent primer layer and were not added. Instead, a benzotriazole-based transparent base sheet was used as the transparent base sheet. 0.8% by mass of an ultraviolet absorber,
A decorative sheet was produced in the same manner as in Example 1, except that a sheet to which 0.8% by mass of a sebacate radical scavenger was added was used. Then, a decorative molded product was produced in the same manner as in Example 1.

Comparative Example 3 A decorative sheet was prepared in the same manner as in Example 2 except that the adhesive layer was formed as a layer having a thickness of 6 μm using chlorinated polypropylene. . Using the decorative sheet, injection molding was performed in the same manner as in Example 2 to obtain a decorative molded product.

[Evaluation of Performance] (1) Bleed: In Examples 1 and 2, when a decorative sheet was produced by printing, no bleeding of the ultraviolet absorber and the light stabilizer on the sheet surface was observed. Similarly, no bleeding was observed in the case of the decorative sheet of Comparative Example 1, but with the decorative sheet of Comparative Example 2, whitening due to bleed was slightly observed on the surface after printing. (2) Weather (light) resistance: According to JIS B 7751,
An accelerated light resistance test was performed on the decorative molded article with an ultraviolet carbon arc lamp type fade meter (black panel temperature: 83 ° C.) to evaluate. As a result, yellowing was observed in Examples 1 and 2 in 1020 hours, Comparative Example 1 in 515 hours, and Comparative Example 2 in 800 hours, which were visually discernable.

As shown in the performance evaluation results, only Examples 1 and 2 exhibited good weather resistance without causing whitening due to bleed-out.

(3) Adhesion immediately after molding: In the grid tape method, it takes time to make cuts in a grid pattern.
During this time, the temperature of the test piece (decorative molded product) decreases. Therefore, the evaluation of the adhesiveness immediately after molding as heat resistance during molding was evaluated by a cross-cut method. In this cross-cutting method, a notch, which crosses at 30 ° and whose depth reaches the resin molded product, is inserted into the surface (decoration sheet surface) of the decorative molded product that cannot be cooled immediately after molding by a cutter knife. The evaluation was made based on whether or not the decorative sheet laminated on the surface could be peeled off from the cross portion of the cut as a starting point.
A sheet in which the decorating sheet was broken and did not peel off except at the center cross portion was good, and a sheet which could be peeled off other than the cross portion was poor. However, this performance evaluation was performed only for Example 2 and Comparative Example 3 in order to compare the adhesion immediately after molding to the resin molded product of the polyolefin resin.

As a result of the above evaluation of adhesion, Example 2
In Comparative Example 3, the result was poor.

[0070]

(1) According to the decorative sheet of the present invention, in addition to the decorativeness of the surface such as a painted feeling and a transparent feeling, an ultraviolet absorber and light stability due to heat during the production and use of the decorative sheet. Good weather resistance can be obtained while preventing whitening of the surface due to bleed-out of the agent. Furthermore, if each of the ultraviolet absorber, the light stabilizer and the adhesive layer is composed of the above-mentioned specific material, good weather resistance can be reliably obtained, and also interlayer adhesion in the decorative sheet layer can be reliably obtained, In addition, when the injection resin is a general-purpose resin such as an ABS resin, a styrene resin, an acrylic resin, a vinyl chloride resin, or a polyolefin resin, the adhesion between the decorative sheet and the resin molded product can be reliably obtained.

(2) According to the simultaneous decorating method for injection molding of the present invention, the effect of the decorative sheet of the present invention can be obtained.
In other words, in addition to the design properties such as surface coating feeling and transparency, in addition to preventing the ultraviolet absorber or light stabilizer from bleeding out to the surface and whitening due to heat during use of the decorative sheet, good weather resistance Can be imparted to a decorative molded product. Furthermore, by using a decorative sheet in which each of the ultraviolet absorber, the light stabilizer and the adhesive layer is made of the above-mentioned specific material, good weather resistance can be surely imparted to the decorative molded article, and the decorative sheet layer Between the decorative sheet and the resin molded product when a general-purpose resin such as ABS resin, styrene resin, acrylic resin, vinyl chloride resin, or polyolefin resin is used as the injection resin. Adhesion can also be reliably imparted to the decorative molded product.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a form example of a decorative sheet of the present invention.

FIG. 2 is a conceptual diagram illustrating an injection molding simultaneous decorating method of the present invention in one embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent base material sheet 2 Transparent primer layer 3 Decorative layer 4 Adhesive layer 41 Suction hole 42 Sheet clamp a Ultraviolet absorber b Light stabilizer Ma Injection mold (male) Mb Injection mold (female) S Decorative sheet

Claims (3)

[Claims] 1. A decorative sheet used for simultaneous injection molding and decorating, wherein an acrylic resin is a main component, and an ultraviolet absorbent and a light stabilizer other than the ultraviolet absorbent are not added to the back surface of the transparent base material sheet.
A transparent primer layer containing an acrylic resin as a main component and a light stabilizer other than an ultraviolet absorber and an ultraviolet absorber added thereto,
A decorative sheet in which a decorative layer and an adhesive layer each containing a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer as a main component of a binder resin are laminated in this order. 2. The method according to claim 1, wherein the ultraviolet absorber is a benzotriazole-based ultraviolet absorber, the light stabilizer is a sebacate-based radical scavenger, and the adhesive layer is a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer. Alternatively, the decorative sheet according to claim 1, comprising an acrylic-modified polyolefin-based resin as a main component. 3. The decorative sheet according to claim 1 or 2 is inserted between the male and female molds with the adhesive layer in contact with the injection resin, and then the molds are clamped. Injecting the resin in a fluid state into the cavity formed by the above, solidifying the resin, opening the mold, and obtaining a decorative molded product in which the decorative sheet is laminated and integrated with the resin molded product. Simultaneous molding decoration method.