Patent Application
20090022968
1. Field of the Invention
The present invention relates to a decorative sheet for use to decorate a formed product and also relates to a formed product decorated with such a decorative sheet and to a vehicle including such a formed product.
2. Description of the Related Art
Recently, it was proposed that a decorative sheet be attached to the surface of a formed product as a technique for decorating various types of formed products. A formed product with a decorative sheet can be recycled more easily than a formed product with a painted surface. In addition, a decorated product can have a different type of fine appearance compared to that of a painted product. That is why a decorative sheet contributes to noticeably improving the appearance of formed products.
The formed product 121 shown in
If a decorative sheet is attached to the body of a formed product with a rugged surface, however, the resultant formed product may have an uneven gloss on the surface, thus possibly diminishing the beauty of its appearance.
Such an uneven gloss 123 appears because the adhesive will often flow and get distributed unevenly while the decorative sheet 110 is being attached. The pamphlet of PCT International Application Publication No. 2007/032223 discloses a technique for providing a flow reducing member, which reduces such a flow of the adhesive, in the adhesive layer in order to minimize the occurrence of the uneven gloss. According to this technique, the flow reducing member, made of a material that has a lower melting point than the material of the adhesive layer, can reduce the flow of the adhesive layer, thus eliminating the uneven distribution of the adhesive and minimizing the occurrence of the uneven gloss.
If such a flow reducing member as the one disclosed in the Pamphlet of PCT International Application Publication No. 2007/032223 is used, however, the surface of the decoration layer or the base member may become rugged, and the surface of the final formed product may sometimes have a concavo-convex pattern, representing the arrangement of the flow reducing member, according to the hardness of the flow reducing member when the decorative sheet is attached to the body of the formed product. Such a concavo-convex pattern is recognized as a dimpled or textured pattern. That is why the technique disclosed in the Pamphlet of PCT International Application Publication No. 2007/032223 is very useful if such a semi-stereoscopic pattern is desired. However, if planar decoration effect is everything, such a technique cannot be used.
In order to overcome the problems described above, preferred embodiments of the present invention provide a decorative sheet that can eliminate the occurrence of such an area of uneven gloss when attached to the body of a formed product and that can achieve a planar decoration effect.
A decorative sheet according to a preferred embodiment of the present invention is designed for use to decorate a formed product. The sheet preferably includes a decoration layer, a base member that supports the decoration layer, and an adhesive layer arranged to adhere the decoration layer and the base member onto the body of the formed product. The adhesive layer includes a first adhesive layer and a second adhesive layer, which is arranged between the first adhesive layer and the base member and which has a melting point that is higher than that of the first adhesive layer by about 18° C. to about 40° C.
In one preferred embodiment of the present invention, if the load deflection temperature of the base member when measured under a load of about 0.45 MPa compliant with the ASTM D648 standard is identified by TA, the melting point of the second adhesive layer is in the range of about (TA−40)° C. to about TA° C.
In another preferred embodiment, the base member has a thickness of about 300 μm to about 800 μm.
In still another preferred embodiment, the first adhesive layer has a melting point of about 100° C. to about 150° C., and the second adhesive layer has a melting point of about 120° C. to about 168° C.
In yet another preferred embodiment, the first adhesive layer has a thickness of about 10 μm to about 30 μm.
In this particular preferred embodiment, the adhesive layer has an overall thickness of about 20 μm to about 60 μm.
In yet another preferred embodiment, if the load deflection temperature of the base member when measured under a load of about 0.45 MPa compliant with the ASTM D648 standard is identified by TA, the base member has a greater tensile strength than the combined tensile strength of the decoration layer and the adhesive layer at least at a particular temperature falling within the range of about (TA−40)° C. to about (TA+50)° C.
In yet another preferred embodiment, the decoration layer is arranged between the base member and the adhesive layer.
In yet another preferred embodiment, the base member is arranged between the decoration layer and the adhesive layer.
In a specific preferred embodiment, the base member is made of a material selected from the group consisting of polycarbonate, polymethyl methacrylate, polyethylene terephthalate, and polyurethane.
A formed product according to a preferred embodiment of the present invention preferably includes a formed product body, and a decorative sheet according to any of the preferred embodiments of the present invention described above, which is attached to the surface of the formed product body.
In one preferred embodiment of the present invention, a portion of the decorative sheet attached to the surface of the formed product body is about 30% to about 50% as thick as the thickest portion thereof.
A vehicle according to another preferred embodiment of the present invention includes a formed product according to any of the preferred embodiments of the present invention described above.
The adhesive layer of a decorative sheet according to various preferred embodiments of the present invention includes a first adhesive layer and a second adhesive layer, which is arranged between the first adhesive layer and a base member and which has a higher melting point than the first adhesive layer. That is to say, the second adhesive layer with relatively low fluidity is arranged inside the first adhesive layer with relatively high fluidity. If the adhesive layer has such a multilayer structure, the overall adhesive layer can be thick enough to maintain sufficient adhesiveness and yet the first adhesive layer, which has relatively high fluidity (i.e., in which the adhesive is likely to get distributed unevenly), can have a reduced thickness. That is to say, even if the adhesive in the first adhesive layer gets distributed unevenly when the decorative sheet is attached to the formed product body, the first adhesive layer is too thin to easily recognize it as an uneven gloss. Thus, in the decorative sheet according to a preferred embodiment of the present invention, an area of uneven gloss will rarely appear when the sheet is attached to the formed product body. In addition, since there is no need to introduce a hard member such as a flow reducing member into the adhesive layer, the planar decoration effect can be achieved just as intended without producing a dimpled or textured pattern.
Also, in the decorative sheet according to a preferred embodiment of the present invention, the difference in melting point between the first and second adhesive layers is no smaller than about 18° C. but no greater than about 40° C. The reasons are as follows. Specifically, if the difference in melting point were less than about 18° C., the second adhesive layer could have too high fluidity to avoid the uneven distribution of the adhesive in the second adhesive layer when the decorative sheet is heated and attached to the formed product body. Or the first adhesive layer could have too low fluidity to eliminate the production of bubbles when adhered to the formed product body. On the other hand, if the difference in melting point exceeded about 40° C., then the first adhesive layer would have too high fluidity to prevent the adhesive from flowing easily when attached to the formed product body. As a result, the final formed product could have a pattern representing that unintentional flow of the adhesive. Or the second adhesive layer could have too low fluidity to allow the adhesive to flow appropriately over the entire adhesive layer (e.g., so as to follow the base member being stretched). Then, the second adhesive layer might crack and ruin the fine appearance of the product. However, as long as the difference in melting point between the first and second adhesive layers is about 18° C. to about 40° C., these problems will rarely happen.
If the load deflection temperature of the base member when measured under a load of about 0.45 MPa compliant with the ASTM D648 standard is identified by TA, the melting point of the second adhesive layer is preferably in the range of about (TA−40)° C. to about TA° C. for the following reasons. Specifically, if the decorative sheet is attached to the formed product body while being stretched, the base member is preferably thick enough to allow the decorative sheet to maintain sufficient mechanical strength even after the sheet has been attached (i.e., stretched). And to increase the stretchability of the base member sufficiently, such a thick base member is preferably heated uniformly. However, if the melting point of the second adhesive layer were less than about (TA−40)° C., then the second adhesive layer heated would have too high fluidity to avoid the uneven distribution of the adhesive in the second adhesive layer. Or the second adhesive layer could even melt and flow out of the base member. On the other hand, if the melting point of the second adhesive layer were higher than about TA° C., then the second adhesive layer would have too low fluidity to allow the adhesive to flow appropriately over the entire adhesive layer (e.g., so as to follow the base member being stretched). Then, the second adhesive layer might crack in some cases. However, as long as the melting point of the second adhesive layer is in the range of about (TA−40)° C. to about TA° C., it is possible to avoid these problems.
The base member preferably has a thickness of about 300 μm to about 800 μm. The reasons are as follows. Specifically, if the base member had a thickness of less than about 300 μm, the base member could be too thin to avoid tearing the decorative sheet or cracking by itself when the decorative sheet is attached to a formed product body with a relatively complicated surface shape. More particularly, that tearing or cracking might occur in a situation where a portion of the decorative sheet attached is about 30% to about 50% as thick as the original thickness of the decorative sheet yet to be attached. On the other hand, if the thickness of the base member exceeded about 800 μm, then the amount of material to make the base member would be too much, or it would take too long a time to heat the base member, to avoid an increase in manufacturing cost. When a base member with such a relatively large thickness of about 300 μm to about 800 μm is used, the base member is preferably heated from both sides at a relatively high temperature and for a sufficient amount of time in order to heat such a thick base member uniformly. As described above, if the melting point of the second adhesive layer is in the range of about (TA−40)° C. to about TA° C., it is still possible to prevent the adhesive layer from coming off the base member even when the base member is heated that way. For that reason, when the base member has a thickness of about 300 μm to about 800 μm, it is particularly preferable that the melting point of the second adhesive layer is in the range of about (TA−40)° C. to about TA° C.
Specifically, if the first adhesive layer has a melting point of about 100° C. to about 150° C. and if the second adhesive layer has a melting point of about 120° C. to about 168° C., then the area of uneven gloss can be eliminated with more certainty.
The first adhesive layer preferably has a thickness of about 10 μm to about 30 μm. This is because if the first adhesive layer had a thickness of less than about 10 μm, the adhesive layer could not be thick enough to maintain sufficient adhesiveness when the decorative sheet is stretched. On the other hand, if the thickness of the first adhesive layer exceeded about 30 μm, then the adhesive in the first adhesive layer would be distributed so unevenly as to form a raised portion that will eventually be recognized as an area of uneven gloss.
The adhesive layer preferably has a thickness of about 20 μm to about 60 μm. The reason is that an adhesive layer with a thickness of less than about 20 μm might have insufficient adhesiveness. On the other hand, if the adhesive layer had a thickness exceeding about 60 μm, then the decorative sheet attached to the formed product body would diminish the beauty of the surface of the formed product. That is to say, the surface of the formed product could become rugged or might experience the orange peel effect.
The base member preferably has a greater tensile strength than the combined tensile strength of the decoration layer and the adhesive layer at least at a particular temperature falling within the range of about (TA−40)° C. to about (TA+50)° C. The decorative sheet is attached to the formed product body while being stretched. That is why if the base member has such a tensile strength, the decoration layer will not crack while the sheet is attached to the formed product body.
In a decorative sheet according to a preferred embodiment of the present invention, the decoration layer may be arranged between the base member and the adhesive layer or the base member may be arranged between the decoration layer and the adhesive layer.
To achieve a significant decoration effect, the base member is preferably made of a material selected from the group consisting of polycarbonate, polymethyl methacrylate, polyethylene terephthalate, and polyurethane. When made of any of these materials, the base member transmits light so much as to make the decoration layer look bright and sharp.
A formed product according to another preferred embodiment of the present invention includes a decorative sheet according to any of the preferred embodiments of the present invention described above, and therefore, has significantly improved appearance.
The present invention is effective particularly when the decorative sheet being attached is stretched to a certain extent or more. More specifically, preferred embodiments of the present invention can be used particularly effectively if a portion of the decorative sheet attached is about 30% to about 50% as thick as the thickest portion thereof.
A formed product according to a preferred embodiment of the present invention has such a fine appearance as to be used effectively as an external decorative member for various types of vehicles.
The present invention provides a decorative sheet that can eliminate the occurrence of an area of uneven gloss when attached to the body of a formed product and that can achieve a planar decoration effect.
Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the present invention is in no way limited to the specific preferred embodiments to be described below.
First, it will be described with reference to
As shown in
The reason why the adhesive layer 104 gets locally raised as described above could also be explained in the following manner. On the left-hand side of
Also, the formed product body 121 is never stretched, and therefore, produces resistance against the decorative sheet 110 being stretched. On the right-hand side of
Thus, as for the adhesive layer 104, the tensile force acting on it is small and yet the reactive force produced there is great. Consequently, these two forces compete with each other, and that portion of the adhesive layer 104 in contact with the formed product body 121 is not stretched so much but gets raised. That is why when the conventional decorative sheet 110 is used, the uneven distribution (or projection) of the adhesive produces the uneven gloss and diminishes the beauty of its appearance.
Hereinafter, a decorative sheet as a specific preferred embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in
The decoration layer 2 is arranged on one 1a of the two principal surfaces of the base member 1. As the decoration layer 2, any of various layers that produce some decoration effects may be used. For example, a pigment containing layer, including a pigment dispersed in a resin binder, may be used. The pigment containing layer may be an ink layer including a colored pigment or a luminescent layer including a luminescent pigment. The ink disclosed in Japanese Patent Application Laid-Open Publication No. 2002-275405 has such good thermal resistance and bending resistance as to be used effectively as a material for the ink layer. Also, as the decoration layer 2, a metallic layer may be used by depositing a metal by an evaporation process. Examples of materials for the metallic layer include tin, aluminum, gold, copper, zinc, silver, indium and their alloys. It should be noted that the decoration layer 2 does not always have to be a single layer as shown in
The base member 1 is made of a thermoplastic resin. Examples of materials for the base member 1 include polycarbonate (PC), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), thermoplastic polyolefin (TPO) and polyurethane (PU). To achieve a significant decoration effect, the base member 1 is preferably made of a material selected from the group consisting of polycarbonate, polymethyl methacrylate, polyethylene terephthalate, and polyurethane. When made of any of these materials, the base member 1 transmits light so much as to make the decoration layer 2 look bright and sharp.
The base member 1 preferably has a thickness of about 50 μm to about 1,000 μm. This range is preferred for the following reasons. Specifically, if the thickness of the base member 1 were less than about 50 μm, the sheet would be difficult to handle or its mechanical strength could be too low to avoid tearing while being attached. Meanwhile, if the thickness of the base member 1 exceeded about 1,000 μm, then the sheet being stretched could not follow the surface of the formed product.
The base member 1 more preferably has a thickness of about 300 μm to about 800 μm. The reasons are as follows. Specifically, if the base member had a thickness of less than about 300 μm, the base member 1 could be too thin to avoid tearing the decorative sheet 10 or cracking by itself when the decorative sheet 10 is attached to a formed product body with a relatively complicated surface shape. More particularly, that tearing or cracking might occur in a situation where a portion of the decorative sheet attached is about 30% to about 50% as thick as the original thickness of the decorative sheet yet to be attached. On the other hand, if the thickness of the base member 1 exceeded about 800 μm, then the amount of material needed to make the base member 1 would be too much, or it would take too long a time to heat the base member 1, to avoid an increase in manufacturing cost.
In this preferred embodiment, the adhesive layer 4 preferably includes a first adhesive layer 4a and a second adhesive layer 4b, which is arranged between the first adhesive layer 4a and the base member 1 and which has a higher melting point than the first adhesive layer 4a. That is to say, the adhesive layer 4 preferably includes the first adhesive layer 4a with a relatively low melting point and the second adhesive layer 4b with a relatively high melting point. On the decoration layer 2, stacked are the second adhesive layer 4b and the first adhesive layer 4a in this order. That is to say, the first adhesive layer 4a is located at the uppermost surface of the decorative sheet 10.
In this preferred embodiment, the adhesive layer is made of a hot-melt type adhesive including a thermoplastic resin as its main ingredient. Examples of preferred materials for the first and second adhesive layers 4a and 4b include elastomers, nylon, synthetic rubbers, polyolefin such as polyurethane or polyurethane acrylate, EVA (ethylene vinylacetate copolymer) and an ethylene copolymer (which is a copolymer consisting of ethylene and another compound). To exhibit sufficient adhesiveness, these resins preferably have a loss modulus G″ of approximately 105 to 106 Pa at about 20° C. or approximately 103 to 104 Pa at about 190° C. when subjected to a solid viscoelasticity measurement. Also, an adhesive made of a resin has a molecular weight distribution. That is to say, there is a difference between the temperature at which the adhesive starts melting and the temperature at which the adhesive finishes melting. However, the “melting point” of the adhesive layer refers herein to a melting point measured by DSC (differential scanning calorimetry).
As described above, the adhesive layer 4 of the decorative sheet 10 of this preferred embodiment includes the first adhesive layer 4a and the second adhesive layer 4b, which is arranged between the first adhesive layer 4a and the base member 1 and which has a higher melting point than the first adhesive layer 4a. When the decorative sheet 10 is attached, the fluidity of the first and second adhesive layers 4a and 4b depends on the levels of their melting points. For that reason, the adhesive layer 4 includes the second adhesive layer 4b with relatively low fluidity inside the first adhesive layer 4a with relatively high fluidity. If the adhesive layer 4 has such a multilayer structure, the occurrence of the area of uneven gloss can be minimized for the following reasons.
As shown in
That is why although the first adhesive layer 4a could get raised due to an uneven distribution of the adhesive as shown in
If the adhesive layer 4 has such a multilayer structure, the overall adhesive layer 4 can be thick enough to maintain sufficient adhesiveness and yet the first adhesive layer 4a, which has relatively high fluidity, can have a reduced thickness. That is to say, even if the adhesive in the first adhesive layer 4a with relatively high fluidity gets distributed unevenly when the decorative sheet 10 is attached to the formed product body, the first adhesive layer 4a is too thin to easily recognize it as an area of uneven gloss.
Thus, in the decorative sheet 10 of this preferred embodiment, an area of uneven gloss will rarely appear. In addition, since there is no need to introduce a hard member such as a flow reducing member into the adhesive layer 4, the planar decoration effect can be achieved just as intended without producing a dimpled or textured pattern.
Also, in the decorative sheet 10 of this preferred embodiment, the difference in melting point between the first and second adhesive layers 4a and 4b preferably is no smaller than about 18° C. but no greater than about 4° C. The reasons are as follows. Specifically, if the difference in melting point were less than about 18° C., the second adhesive layer 4b could have too high fluidity to avoid the uneven distribution of the adhesive in the second adhesive layer 4b, too. Or the first adhesive layer 4a could have too low fluidity to eliminate the production of bubbles when adhered to the formed product body 21. On the other hand, if the difference in melting point exceeded about 40° C., then the first adhesive layer 4a would have too high fluidity to prevent the adhesive from flowing easily when attached to the formed product body 21. As a result, the final formed product could have a pattern representing that unintentional flow of the adhesive. Or the second adhesive layer 4b could have too low fluidity to allow the adhesive to flow appropriately over the entire adhesive layer 4 (e.g., so as to follow the base member 1 being stretched). Then, the second adhesive layer 4b might crack and ruin the fine appearance of the product. However, as long as the difference in melting point between the first and second adhesive layers 4a and 4b is about 18° C. to about 40° C., these problems will rarely happen.
If the load deflection temperature of the base member 1 (more specifically, the load deflection temperature thereof when measured under a load of about 0.45 MPa compliant with the ASTM D648 standard) is identified by TA, the melting point of the second adhesive layer 4b is preferably in the range of about (TA−40)° C. to about TA° C. The decorative sheet 10 is preferably attached to the formed product body at a temperature of about (TA−40)° C. to about (TA+50)° C. as will be described later. That is why if the melting point of the second adhesive layer 4b were less than about (TA−40)° C., then the second adhesive layer 4b heated would have too high fluidity to avoid the uneven distribution of the adhesive in the second adhesive layer 4b, too. On the other hand, if the melting point of the second adhesive layer 4b were higher than about TA° C., then the second adhesive layer 4b would have too low fluidity to allow the adhesive to flow appropriately over the entire adhesive layer 4 (e.g., so as to follow the base member 1 being stretched). Then, the second adhesive layer 4b might crack in some cases.
When the base member 1 has a thickness of about 300 μm to about 800 μm, it is particularly preferable that the melting point of the second adhesive layer 4b is in the range of about (TA−40)° C. to about TA° C. If a base member 1 with such a relatively large thickness is used, the base member 1 is preferably heated from both sides at a relatively high temperature and for a sufficient amount of time in order to heat such a thick base member 1 uniformly. However, if the melting point of the second adhesive layer 4b is in the range of about (TA−40)° C. to about TA° C., it is still possible to prevent the adhesive layer 4 from coming off the base member 1 even when the base member 1 is heated that way.
Specifically, if the first adhesive layer 4a has a melting point of about 100° C. to about 150° C. and if the second adhesive layer 4b has a melting point of about 120° C. to about 168° C., then the area of uneven gloss can be eliminated with more certainty.
The first adhesive layer 4a preferably has a thickness of about 10 μm to about 30 μm. This is because if the first adhesive layer 4a had a thickness of less than about 10 μm, the adhesive layer 4 could not be thick enough to maintain sufficient adhesiveness when the decorative sheet 10 is stretched. On the other hand, if the thickness of the first adhesive layer 4a exceeded about 30 μm, then the adhesive in the first adhesive layer 4a would be distributed so unevenly as to form a raised portion that will eventually be recognized as an area of uneven gloss.
The adhesive layer 4 preferably has a thickness of about 20 μm to about 60 μm. The reason is that an adhesive layer 4 with a thickness of less than about 20 μm might have insufficient adhesiveness. On the other hand, if the adhesive layer 4 had a thickness exceeding about 60 μm, then it could be difficult to flatten the surface of the decorative sheet 10 attached to the formed product body. That is to say, the surface of the formed product could become rugged or might experience an orange peel effect.
Also, the base member 1 preferably has a greater tensile strength than the combined tensile strength of the decoration layer 2 and the adhesive layer 4 at least at a particular temperature falling within the range of about (TA−40)° C. to about (TA+50)° C., which is a preferable forming temperature (or the temperature at which the decorative sheet 10 is attached). The decorative sheet 10 is attached to the formed product body while being stretched. That is why if the base member 1 has such a tensile strength, the decoration layer 2 will not crack while the sheet 10 is attached to the formed product body.
In the exemplary configuration shown in
Optionally, as shown in
Furthermore, the adhesive layer 4 does not have to include two adhesive layers but may also include three or more adhesive layers. For example, the adhesive layer 4 may further include a third adhesive layer 4c between the second adhesive layer 4b and the base member 1 as shown in
Hereinafter, a method of making a formed product using the decorative sheet 10 will be described with reference to
The vacuum forming system 100 shown in
The vacuum vessel 34 includes a main vessel 34a that houses the gripping frame 30 and the supporting stage 31, and a sub-vessel 34b that houses the heater 33. When the decorative sheet 10 is heated, the heater 33 is introduced into the main vessel 34a.
The supporting stage 31 has a plurality of openings 31a, through which the air inside the main vessel 34a can be exhausted. Although not shown in
Using this vacuum forming system 100, a formed product may be made in the following manner, for example.
First, as shown in
Thereafter, as shown in
Subsequently, as shown in
Thereafter, as shown in
Subsequently, as shown in
The decorative sheet 10 of this preferred embodiment includes the adhesive layer 4 including the first and second adhesive layers 4a and 4b. That is why in any of this series of process steps, the adhesive layer 4 is not easily raised locally, and therefore, the area of uneven gloss can be virtually eliminated. Thus, by using the decorative sheet 10 of this preferred embodiment, a formed product can be decorated without diminishing the beauty of its appearance. For that reason, the decorative sheet 10 can be used effectively to decorate a formed product with significant ruggedness, e.g., to decorate a deep-drawn formed product.
The present invention is effective particularly when the decorative sheet 10 being attached is stretched to a certain extent or more. More specifically, the present invention can be used particularly effectively if a portion of the decorative sheet 10 attached is about 30% to about 50% as thick as the thickest portion thereof.
The present inventors actually made decorative sheets 10 as samples of the preferred embodiments described above, attached each of those sheets 10 to a formed product body 21, and rated the resulting appearance.
In those samples of the decorative sheets 10, the base member 1, decoration layer 2 and first and second adhesive layers 4a and 4b had approximate thicknesses of 500 μm, 20 μm, 25 μm and 25 μm, respectively. Polycarbonate was used as a material for the base member 1 and a metallic layer was formed as the decoration layer 2 by depositing aluminum by an evaporation process. The first and second adhesive layers 4a and 4b were made of adhesives of one of 2000, 3000, 4000 and 7000 series produced by Daicel Chemical Industries, Ltd. or X95 produced by Toyobo Co., Ltd.
The decorative sheets 10 were heated to a temperature of about 190° C. in the process step shown in
The following Table 1 summarizes the respective melting points of the first and second adhesive layers 4a and 4b, their temperature differences, and the ratings of their appearances. Specifically, the appearance of each of those decorative sheets 10 was rated by checking, with the eyes, how a portion of the decorative sheet 10 that had stretched 150% looked. If no area of uneven gloss was recognized, the decorative sheet 10 was rated GOOD (which is indicated by the open circles ◯ in Table 1). On the other hand, if any areas of uneven gloss were recognized, the decorative sheet 10 was rated BAD (which is indicated by the crosses X in Table 1). Table 1 also lists, as comparative examples, sheets having the same configuration as the decorative sheets 10 of this preferred embodiment except that the difference in melting point between the first and second adhesive layers 4a and 4b was outside of the range of about 18° C. to about 40° C.:
As can be seen from Table 1, in Comparative Examples 1 to 3 in which the differences in melting point were outside of the range of about 18° C. to about 40° C., areas of uneven gloss were observed. On the other hand, in Examples 1 to 3 of preferred embodiments of the present invention in which the differences in melting point were within the range of about 18° C. to about 40° C., no areas of uneven gloss were recognized and fine appearances were realized. In Comparative Example 4, as the melting point of the first adhesive layer 4a had a range, the difference in melting point also had a range. However, since the difference in melting point also failed to fall within the preferred range of about 18° C. to about 40° C., areas of uneven gloss were also observed and sufficiently good appearance could not be realized, either. Meanwhile, even if the melting point(s) of the first and/or second adhesive layer(s) 4a and/or 4b had range(s) but as long as the difference between their melting points fell within the range of about 18° C. to about 40° C., a fine appearance was also realized.
The following Table 2 summarizes the load deflection temperatures TA of the base member 1, the melting points of the second adhesive layer 4b, their differences, and the ratings of their appearances:
As can be seen from Table 2, in Comparative Examples 5 and 6 in which the melting point of the second adhesive layer 4b was outside of the range of about (TA−40)° C. to about TA° C., areas of uneven gloss were observed. On the other hand, in Examples 4 to 7 of preferred embodiments of the present invention in which the melting point of the second adhesive layer 4b was within the range of about (TA−40)° C. to about TA° C., no areas of uneven gloss were recognized and fine appearances were realized. It should be noted that the melting point of the second adhesive layer 4b could have some range. Even so, the melting point of the second adhesive layer 4b preferably falls within the range of about (TA−40)° C. to about TA° C.
A formed product decorated with the decorative sheet 10 of this preferred embodiment has a fine appearance and can be used effectively as an exterior member for various types of vehicles. For example, the formed product can be used effectively as the tank housing 51, the front fender 52 or the tail cowl 53 of a motorcycle 50 as shown in
Preferred embodiments of the present invention provide a decorative sheet that can eliminate the occurrence of an area of uneven gloss when attached to the body of a formed product and that can achieve a planar decoration effect.
A formed product decorated with the decorative sheet according to various preferred embodiments of the present invention has such a fine appearance as to be used effectively as an exterior member for various types of vehicles including passenger cars, buses, trucks, motorcycles, tractors, airplanes, motorboats, and civil engineering vehicles.
While the present invention has been described with respect to preferred embodiments thereof, it will be apparent to those skilled in the art that the disclosed invention may be modified in numerous ways and may assume many embodiments other than those specifically described above. Accordingly, it is intended by the appended claims to cover all modifications of the invention that fall within the true spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2007-186863 filed on Jul. 18, 2007, the entire contents of which are hereby incorporated by reference. Furthermore, the entire contents of Japanese Patent Application No. 2008-180943 filed on Jul. 11, 2008, are hereby incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-186863 | Jul 2007 | JP | national |
