JP2007245647A - Decoration sheet for insert molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decoration sheet suitable for simultaneous decoration by concurrently achieving hiding, blocking resistance and settling safety of a hiding layer in the decoration sheet for insert molding. <P>SOLUTION: The decoration sheet for insert molding consists of a substrate sheet, an image pattern layer, the hiding layer and an adhesive layer overlying in this order from the surface, wherein the hiding layer contains a resin of a glass transition point Tg(°C) between 50 and 75, and an inorganic pigment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a decorative sheet used for insert molding.

Conventionally, a decorative molded product in which the surface of an adherend such as a resin molded product is decorated has been used for various purposes. For example, in the injection molding simultaneous decorating method disclosed in Patent Document 1 and the like, a decorative molded product whose surface is decorated by laminating and integrating a molding decorative sheet on the surface simultaneously with molding of a resin molded product Is obtained.
Since the above decorative sheet for molding is decorated by extending the sheet, the thickness of the stretched part becomes thin, so the resulting decorative molded product (in the stretched part of the sheet) is the color of the adherend. It was easy to be affected. This is because, in the stretched decorative sheet for molding, the thickness of the colored pattern ink layer becomes thin and the concealability is lowered. Therefore, since the color of the adherend itself appears to be transmitted through the portion where the concealability of the decorative sheet for molding is lowered, the color is different from the surroundings. Therefore, various studies have been made to prevent the color tone of the molded product from being influenced by the color of the injection resin.

For example, in Patent Document 2, an injection molding simultaneous painting sheet is added to a transparent base sheet 1 to which an arbitrary colorant is added and an acrylic resin is a main component, and an acrylic resin and a vinyl chloride-vinyl acetate copolymer. A pattern layer having a binder resin as a main component of a binder resin, a mixture of an inorganic pigment and an organic pigment or a single inorganic pigment as a colorant, and an acrylic resin and a vinyl chloride-vinyl acetate copolymer It is proposed to provide a colored hiding layer comprising a mixture of the above or a vinyl chloride-vinyl acetate copolymer alone as a main component of a binder resin.
Moreover, in patent document 3, it forms by printing, coating, etc. on the whole surface, the 1st layer which consists of a base material sheet, the 2nd layer which has the pattern layer formed by printing etc. which contains an organic pigment as a coloring agent, In addition, there is disclosed a decorative sheet having a configuration in which a third layer composed of all solid layers containing an inorganic pigment as a main component of a colorant is laminated.
And in patent document 4, the thermoplastic resin base material sheet contains at least a hiding layer containing a colorant in the resin, a colorant in the resin, the same hue as the hiding layer, and darker than the hiding layer. Proposes a decorative sheet for molding in which colored layers having colors are laminated in that order.
However, even though these concealing layers have high concealing properties, it is difficult to establish concealing properties, blocking resistance and sedimentation stability due to low blocking resistance and sedimentation stability.

Japanese Patent Publication No. 50-19132 JP 2000-108160 A JP 2000-141549 A Japanese Patent Laid-Open No. 2001-9980 JP 2004-322501 A

  Under such circumstances, the present invention provides a decorative sheet suitable for simultaneous decoration by enhancing the concealing property, blocking resistance and sedimentation stability of the concealing layer of the decorative sheet for insert molding. Is an issue.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by making improvements to the concealment layer. The present invention has been completed based on such findings.
That is, the gist of the present invention is as follows.
1. A decorative sheet for insert molding in which a base sheet, a pattern layer, a concealing layer and an adhesive layer are laminated in order from the surface, wherein the concealing layer has a glass transition point Tg (° C.) of 50 to 75. And a decorative sheet for insert molding comprising an inorganic pigment.
2. The decorative sheet for insert molding as described in 1 above, wherein the base sheet is made of an acrylic resin.
3. 3. The decorative sheet for insert molding according to 1 or 2 above, wherein the resin of the concealing layer is an acrylic resin.
4). 4. The decorative sheet for insert molding according to any one of 1 to 3 above, wherein the inorganic pigment of the concealing layer includes an inorganic pigment selected from at least one selected from the group consisting of a white inorganic pigment, a yellow inorganic pigment, and a brown inorganic pigment.
5). 5. The decorative sheet for insert molding as described in 4 above, wherein the white inorganic pigment is titanium oxide, the yellow inorganic pigment is iron oxide yellow, and the brown inorganic pigment is a petal.
6). The thickness-converted PV ratio of the hiding layer [reference thickness: 2 μm, where the PV ratio is (mass of pigment solids / mass of resin solids)] is 2.5 or more. The decorative sheet for insert molding according to any one of the above.

  ADVANTAGE OF THE INVENTION According to this invention, the concealment property of the concealment layer of a decorative sheet for insert molding, blocking resistance, and sedimentation stability can be erected, and, thereby, the decorating sheet suitable for simultaneous decorating can be provided. .

Hereinafter, the present invention will be described with reference to the drawings. Drawing 1 is a mimetic diagram showing the section of the decorating sheet of the present invention.
The decorative sheet 10 for insert molding of the present invention is formed by laminating a base sheet 11, a pattern layer 12, a concealing layer 13, and an adhesive layer 14 in order from the surface.
Moreover, FIG. 2 is a schematic diagram which shows the cross section of the insert film using the decorating sheet of this invention. The insert film 30 is manufactured by integrating the surface of the adhesive layer 14 of the decorative sheet 10 and the surface of the backer sheet 20.
In the present invention, the glass transition point Tg (° C.) of the resin as a binder used for the concealing layer 13 is required to be 50 to 75 ° C. It is because blocking resistance will fall that it is less than 50 degreeC, and sedimentation stability will deteriorate when it exceeds 75 degreeC. Here, blocking resistance refers to the property that the printed surface does not stick to each other when printed materials are stacked or stacked with other sheets after printing, and sedimentation stability refers to the precipitation of pigments during storage of ink. Then, it hardens at the bottom or generates a hard cake, and does not easily re-disperse even when stirred. Blocking resistance and sedimentation stability are important properties required for printing inks and the like.
Furthermore, the hiding layer 13 according to the present invention needs to contain an inorganic pigment having a high hiding property. The inorganic pigment preferably contains an inorganic pigment selected from at least one selected from the group consisting of a white inorganic pigment, a yellow inorganic pigment, and a brown inorganic pigment. If necessary, the pigment may further contain a black inorganic pigment such as carbon black.

  The base material sheet 11 according to the present invention is preferably a transparent resin sheet in order to improve the design of the pattern layer 12. As this resin, an acrylic resin that is excellent in transparency and, as a result, can impart an excellent coating feeling is further preferable. Examples of the acrylic resin include polymethyl (meth) acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, methyl (meth) acrylate-styrene copolymer Acrylic resin such as coalescence (however, (meth) acrylate means acrylate or methacrylate) is used as a single layer or a mixture of two or more types as a sheet of a single layer or a laminate of two or more layers. The base sheet 11 may be colored and transparent in addition to colorless and transparent. In addition, in the base sheet 11, if necessary, lubricants such as polyethylene wax and paraffin wax, lubricants composed of particles of silica, spherical α-alumina, benzotriazole, benzophenone, fine particle oxidation Various additives such as cerium-based ultraviolet absorbers, hindered amine-based radical scavengers and other light stabilizers, plasticizers, stabilizers, and colorants may be added to adjust the physical properties. Moreover, you may add resin other than an acrylic resin as an auxiliary material. Although the thickness of the base material sheet 11 is not specifically limited, Generally, it is about 20-500 micrometers.

  The design pattern layer 12 according to the present invention is a layer that expresses a pattern, a character, and a pattern-like design. The pattern of the pattern pattern layer 12 is arbitrary, but is, for example, a pattern made of wood, stone, cloth, sand, geometric pattern, characters, and the like. The pattern layer 12 is basically not particularly limited except that the binder resin is made of a specific resin. The pattern layer is usually formed by a known printing method such as gravure printing with printing ink. The binder resin is preferably mainly composed of an acrylic resin alone or a mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer. When an acrylic resin is used as the base sheet 11, the acrylic resin is used for adhesion to the base sheet 11, and further mixed with a vinyl chloride-vinyl acetate copolymer or another acrylic resin, printing suitability and molding Suitability becomes more suitable. Here, as an acrylic resin, it selects suitably from the thing similar to what was listed in the above-mentioned base material sheet, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, alkyl methacrylate (meth) acrylate such as octyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) An acrylic polyol obtained by copolymerizing a (meth) acrylic acid ester having a hydroxyl group in a molecule such as acrylate can also be used. As the vinyl chloride-vinyl acetate copolymer, those having a vinyl acetate content of about 5 to 20% by mass and an average degree of polymerization of about 350 to 900 are usually used. If necessary, the vinyl chloride-vinyl acetate copolymer may be further copolymerized with a carboxylic acid such as maleic acid or fumaric acid. The mixing ratio of the acrylic resin and the vinyl chloride-vinyl acetate copolymer is about acrylic resin / vinyl chloride-vinyl acetate copolymer = 1/9 to 9/1 (mass ratio). In addition, as a subcomponent resin, if necessary, other resins such as thermoplastic polyester resin, thermoplastic urethane resin, chlorinated polyethylene, chlorinated polypropylene, and other chlorinated polyolefin resins may be mixed. Also good.

The resin used as the binder for the concealing layer 13 according to the present invention only needs to have a glass transition point Tg (° C.) within the above-mentioned range, but the adhesion between the pattern layer 12 and the base sheet 11 and printability. From the viewpoint of moldability, it is preferable to use one kind of acrylic resin, a mixture of two or more kinds of acrylic resins, or a mixture of acrylic resin and vinyl chloride-vinyl acetate copolymer, similarly to the pattern layer 12. However, in order to adjust the glass transition point Tg (° C.) of the resin within the range of 50 to 75 ° C., it is more preferable to use one kind of acrylic resin alone or a mixture of two or more kinds of acrylic resins. preferable. As the acrylic resin and vinyl chloride-vinyl acetate copolymer in the concealing layer 13, those described in the above-mentioned pattern layer 12 may be used. As the acrylic resin, polymethyl methacrylate and polybutyl methacrylate are preferable, and a mixture of polymethyl methacrylate and polybutyl methacrylate is particularly preferable. And the glass transition point Tg (degreeC) of resin can be adjusted by selecting suitably the kind and mixing ratio of these resin. Further, if necessary, for example, a resin such as a thermoplastic polyester resin, a thermoplastic urethane resin, a chlorinated polyethylene, a chlorinated polyolefin such as chlorinated polypropylene, or the like can be mixed as a subcomponent resin, and the glass transition point Tg ( C)) may be adjusted. Such a concealing layer is usually formed by a known printing method such as gravure printing or a coating method such as gravure coating with printing ink or paint. The thickness of one layer of the colored hiding layer is usually 2 μm Degree.

Among the inorganic pigments used in the masking layer 13 according to the present invention, examples of white inorganic pigments include titanium dioxide, zinc white, and antimony trioxide. Titanium dioxide is preferable because of its high masking properties.
Examples of yellow inorganic pigments include iron oxide yellow, yellow lead, cadmium yellow, titanium yellow, and antimony yellow. Iron oxide yellow is preferable in that it does not contain harmful substances.
Examples of brown inorganic pigments include petal, mercury sulfide, cadmium red, chrome vermilion, amber, low amber, burnt amber, yellow ocher, van dyke brown, shenna, roshenna, burnt senna, etc. It is preferable in that it is easy to obtain.

In general, the greater the amount of the inorganic pigment in the hiding layer 13, the higher the hiding property of the hiding layer 13.
From the above, the thickness of the normal hiding layer is 2 μm In consideration of the degree, the “thickness-converted PV ratio” of the resin composition layer can be used as an index of the amount of the inorganic pigment of the hiding layer 13.
Thickness conversion PV ratio = PV ratio × [(Resin composition layer thickness (μm) / 2 (μm)]
Here, [PV ratio = (mass of solid content of pigment / mass of solid content of resin)].
In the present invention, when the PV ratio of the concealing layer is 4, when the thickness of the concealing layer is 2 μm, the “thickness converted PV ratio” is 4, and when the thickness of the concealing layer is 4 μm, the “thickness converted PV ratio” Is 8 and the thickness of the concealing layer is 1 μm, the “thickness converted PV ratio” is 2. When the concealing layer 13 is composed of a plurality of resin composition layers, the PV ratios in terms of thickness of the resin composition layers may be accumulated. When the thickness-converted PV ratio of the concealing layer is 2.5 or more, high concealing property can be enjoyed, and when it is 2.8 or more, it is particularly preferable. However, if the thickness-converted PV ratio exceeds 20, it is difficult to enjoy the merit of improving the concealing property, while the concealing layer becomes too thick and the disadvantage of high cost becomes large, which is not preferable.

The adhesive layer 14 according to the present invention is selected from a wide range of resins having adhesion to the concealing layer 13, printing suitability, and molding suitability. Specifically, two-component curable urethane resin using blocked isocyanate as a curing agent, chlorinated polyolefin such as chlorinated polypropylene, acrylic resin, vinyl chloride-vinyl acetate copolymer, and acrylic resin and vinyl chloride-vinyl acetate copolymer. It is preferably selected from a mixture with a polymer. As the acrylic resin and vinyl chloride-vinyl acetate copolymer in the adhesive layer, those described in the above-mentioned picture pattern layer 12 may be used. Moreover, what is necessary is just to use these mixing ratios in the ratio range described in the above-mentioned pattern pattern layer 12. FIG. By using these resins in the adhesive layer, adhesion between the insert molding decorative sheet 10 and the backer sheet 20 can be obtained. In addition, you may use together resin other than the above in the range as a subcomponent in an adhesive bond layer. The resin to be used in combination is selected mainly considering the adhesiveness with the injection resin.
When the backer sheet 20 is an ABS resin or a polyolefin resin, a two-component curable urethane resin using a blocked isocyanate as a curing agent, a chlorinated polyolefin such as chlorinated polypropylene, or the like is preferable as the adhesive layer 14.

  The thickness of the adhesive layer 14 may be appropriately determined according to the required physical properties and the like, but is usually about 1 to 100 μm. Further, the method for forming the adhesive layer 14 is not particularly limited, but usually, known ink printing or coating such as gravure printing, roll coating, etc. is used as an ink or coating liquid composed of a resin liquid obtained by diluting the above resin with a diluent solvent. Form by means. Further, in the adhesive layer, in order to adjust and improve various physical properties such as printing (or coating) suitability of the ink (or coating liquid), other auxiliary materials such as constitution Various additives such as pigments may be added.

  As the backer sheet 20 in which the decorative sheet 10 of the present invention is integrated before the vacuum forming via the adhesive layer 14, ABS resin, polyolefin resin, styrene resin, acrylic resin, vinyl chloride resin, polycarbonate resin, etc. preferable. As the polyolefin resin, a polypropylene resin is preferable. Of these resins, ABS resin and polypropylene resin are particularly preferable. Since the backer sheet 20 is used to integrate and reinforce the decorative sheet 10 and retain the form of the integrated product, the backer sheet 20 preferably has a thickness of 100 to 500 μm.

The method for producing the decorative sheet 10 of the present invention includes, for example, a pattern printing layer 12, a concealing layer 13 and an adhesive layer 14 sequentially applied to a base sheet 11 by known printing or coating means such as gravure printing and roll coating. What is necessary is just to laminate. In the case where there are a plurality of concealing layers 13, one layer may be laminated and then dried, and then the next layer may be laminated.
Next, a method for producing a decorative molded product by insert molding using the decorative sheet 10 of the present invention will be described. The decorative sheet 10 of the present invention is bonded and integrated with the backer sheet 20 by dry lamination or the like to form the insert film 30. The insert film 30 is subjected to predetermined molding by vacuum forming.
3, 4, and 5 are respectively a process schematic diagram showing a heating stage before vacuum forming in a vacuum forming process of an insert film using the decorative sheet of the present invention, and a process showing a vacuum forming preparation stage after completion of the heating stage. It is a process schematic diagram which shows a schematic diagram and vacuum forming.
FIG. 6 is a process schematic diagram showing an insert film trimming process using the decorative sheet of the present invention.
7 and 8 are process schematic diagrams showing the injection molding preparation stage and injection molding, respectively, in the insert film injection molding process using the decorative sheet of the present invention.
In FIG. 3, the insert film 30 fixed to a fixed frame (not shown) is heated by a heater 42 until a predetermined temperature at which the insert film 30 is softened, and the insert film 30 heated and softened as shown in FIG. As shown in FIG. 5, air is sucked from the vacuum molding die 41 with a vacuum pump (not shown) at the same time to firmly attach the insert film 30 to the vacuum molding die 41.
After the insert film 30 is in close contact with the vacuum mold 41, the vacuum mold 41 is removed from the insert film 30 formed by cooling and molding the insert film 30, and the insert film 30 molded from the fixed frame is removed.
Next, an excess portion of the insert film 30 vacuum-formed in the trimming step shown in FIG. 6 is cut out, and the insert film 30 thus trimmed is fitted into the injection mold 51 as shown in FIG. 7, and as shown in FIG. The injection resin is driven into the backer sheet 20 side. Finally, it is taken out from the injection mold 51 to obtain a decorative molded product. (For details, see, for example, Patent Document 5)

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The glass transition point Tg (° C.) of the resin, the hiding property of the hiding layer, the blocking resistance and the sedimentation stability were measured according to the following methods.
1. Glass transition point Tg (° C) of resin
The test piece is heated from room temperature at a rate of 20 ° C./min, the calorific value is measured with a differential scanning calorimeter (DSC), and an endothermic curve diagram or an exothermic curve diagram is created. Each extended line was drawn, and the intersection of the 1/2 straight line between the two extended lines and the endothermic curve or exothermic curve was defined as Tg.
2. Concealment After printing the concealment layer on a colorless and transparent sheet, it was judged according to the following criteria that the color appearance was different between the case where the back side of the print sheet was white and the case where it was black.
○: No difference in appearance or almost no state.
(Triangle | delta): There exists a problem in actual use in the state in which there are some differences in appearance.
X: There is a problem in actual use in a state where the appearance is significantly different.
4). Blocking resistance The printed surface and the non-printed surface of the concealing layer are overlapped and a load of 2.94 MPa is applied by a blocking tester and left at 40 ° C. for 72 hours. It was evaluated by.
○: There is no resistance when peeling the stacked printed sheets.
Δ: There is a slight resistance (peeling sound) when the stacked printed sheets are peeled off.
X: In a state where there is resistance when the stacked printed sheets are peeled off, the printed sheet is further reversed (the concealing layer is transferred to the non-printed sheet).
5). Sedimentation stability The sedimentation level of the pigment during storage of the ink used for the masking layer was evaluated according to the following index.
○: The ink pigment is hardened at the bottom of the container or a hard cake is generated, but it is redispersed by stirring, or the bottom of the ink is not hardened or hard cake is present.
X: The case where the pigment of the ink is hardened at the bottom of the container or a hard cake is generated and is not redispersed by stirring.

Examples 1-4 and Comparative Examples 1-4
A pattern sheet (thickness 1 μm) made of polybutyl methacrylate / vinyl chloride-vinyl acetate copolymer (mass ratio: 2/1) on a base sheet (thickness 75 μm) made of polybutyl methacrylate resin, polymethyl methacrylate 8 types of decorative sheets by sequentially stacking a concealing layer (thickness 2 μm) made of a mixture of polybutyl methacrylate and an inorganic pigment and an adhesive layer (thickness 10 μm) made of a two-component curable urethane resin adhesive Was prepared.
The mixing ratio (mass ratio) of polymethyl methacrylate and polybutyl methacrylate was adjusted so that the resin of the concealment layer had a Tg of the resin shown in Table 1.
Moreover, the inorganic pigment of a concealment layer mixed the white inorganic pigment, the yellow inorganic pigment, and the brown inorganic pigment in 5/45/50 (mass ratio) in Examples 1-2 and Comparative Examples 1-4. In Example 4, a yellow inorganic pigment and a brown inorganic pigment were mixed at a ratio of 50/50 (mass ratio). In Example 4, only the yellow inorganic pigment was used. In addition, titanium oxide was used as a white inorganic pigment, iron oxide yellow was used as a yellow inorganic pigment, and a petite was used as a brown inorganic pigment.
The concealing property, blocking resistance and sedimentation stability of the concealing layer of these 8 types of decorative sheets were evaluated. The results are shown in Table 1.

  As can be seen from Table 1, each of the decorative sheets of Examples 1 to 4 has a glass transition point Tg (° C) of the resin within a range of 50 to 75 ° C as a concealing layer, and a predetermined inorganic pigment is predetermined. Therefore, the concealing property, blocking resistance, and sedimentation stability of the concealing layer were all good.

  Next, after the decorative sheets of Examples 1 to 4 were bonded and integrated with a backer sheet made of ABS resin by dry lamination to obtain four types of insert films, these four types of insert films were fixed to a fixed frame. The insert film was heated with a heater at about 300 ° C. until the temperature of the insert film reached about 160 ° C. In the same manner as above, the heated and softened insert film was subjected to a vacuum molding process, a trimming process, and an injection molding process to obtain four types of decorative molded products. As a result of visually observing the most elongated portion (elongation rate: 150%) of these decorative molded products, the base (backer sheet) was not particularly visible, and no color difference from the flat portion was observed.

  The decorative sheet for insert molding of the present invention is suitably used for various decorative molded products.

It is a schematic diagram which shows the cross section of the decorating sheet of this invention. It is a schematic diagram which shows the cross section of the insert film using the decorating sheet of this invention. It is a process schematic diagram which shows the heating step before vacuum forming in the vacuum forming process of the insert film using the decorating sheet of this invention. It is a process schematic diagram which shows the vacuum forming preparation stage after completion | finish of a heating stage in the vacuum forming process of the insert film using the decorating sheet of this invention. In the vacuum forming process of the insert film using the decorating sheet of this invention, it is a process schematic diagram which shows vacuum forming. It is a process schematic diagram which shows the trimming process of the insert film using the decorating sheet of this invention. It is a process schematic diagram which shows the preparatory stage of injection molding in the injection molding process of the insert film using the decorating sheet of this invention. It is a process schematic diagram which shows injection molding in the injection molding process of the insert film using the decorating sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Decoration sheet 11 Base material sheet 12 Pattern pattern layer 13 Concealment layer 14 Adhesive layer 20 Backer sheet 30 Insert film 41 Vacuum molding die 42 Heater 51 Injection molding die

Claims (6)

  A decorative sheet for insert molding in which a base sheet, a pattern layer, a concealing layer and an adhesive layer are laminated in order from the surface, wherein the concealing layer has a glass transition point Tg (° C.) of 50 to 75. And a decorative sheet for insert molding comprising an inorganic pigment.   The decorative sheet for insert molding according to claim 1, wherein the base sheet is made of an acrylic resin.   The decorative sheet for insert molding according to claim 1 or 2, wherein the resin of the concealing layer is an acrylic resin.   The decorative sheet for insert molding according to any one of claims 1 to 3, wherein the inorganic pigment of the hiding layer includes an inorganic pigment selected from the group consisting of a white inorganic pigment, a yellow inorganic pigment, and a brown inorganic pigment.   The decorative sheet for insert molding according to claim 4, wherein the white inorganic pigment is titanium oxide, the yellow inorganic pigment is iron oxide yellow, and the brown inorganic pigment is a dial.   The thickness-converted PV ratio [reference thickness: 2 μm, where PV ratio is (mass of solid content of pigment / mass of solid content of resin)] of 2.5 or more. The decorative sheet for insert molding according to any one of the above.

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