JPS6362552B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermosetting resin molded product having a transparent pattern such as onyx, opal, or marble. Our goal is to provide the following. Prior art related to the field of the present invention is US Pat. No. 3,396,067. According to the patent, certain glass powders with a particle size of approximately 100 mesh or less (e.g., Ferro frit #3134, #3278) are
A method for producing a molded article characterized by adding it to ~85% unsaturated polyester resin to impart an onyx-like pattern to the molded article is specified. Generally, in a mixed system of a liquid and powder solid particles that are insoluble in the liquid and have an amorphous shape, even if the refractive index of each is the same, at some of the grain boundaries of the solid particles, Light scattering occurs because there is always a surface with an angle greater than or equal to the critical angle that totally reflects the incident light. The appearance of such a mixed system is that when the solid particle size is small, it exhibits a semi-opalescent appearance, and as the particle size increases, transparency increases due to a decrease in light scattering, but some parts become glittery. It begins to exhibit visible brilliance. Therefore, it would be extremely difficult to make such a mixed system completely transparent and uniform in appearance, but it is possible to use spherical particles with a very narrow particle size distribution to minimize scattering at grain boundaries. It seems possible to obtain a fairly high degree of transparency. In addition, to produce glass powder used in such cases, it is usually ground using a ball mill, vibration mill, etc., but the particle size distribution of the powder obtained by these methods ranges over a wide range (1 to 300 μm). degree) The grain shape is amorphous with many protrusions that easily cause light scattering. Furthermore, there is always some deviation in the refractive index of glass and resin depending on each lot, and resin molded products that are a mixture of these contain considerable non-uniformity factors.
Even if no pattern is applied with a toner, the molded product has a transparent appearance and an appearance with an indistinct pattern. When such a molded product is obtained by the method of the prior art, the hot water resistance and chemical resistance of the molded product are extremely poor, and it is virtually impossible to use it for bathtubs, wash basins, etc. Currently, there are restrictions. In view of the current situation, the inventors have conducted various studies on the production of thermosetting resin molded articles having transparent patterns such as onyx, opal, or marble, which have extremely excellent hot water resistance and chemical resistance. As a method for improving hot water resistance and chemical resistance, (1) a coating layer with extremely high hot water resistance and chemical resistance is formed on the surface of the molded product. (2) Improving the hot water resistance and chemical resistance of the base thermosetting resin used. (3) Possible methods include improving the chemical resistance of glass powder used as a filler. Therefore, we used a general type ortho-unsaturated polyester resin (hot water resistance 80 hours) as the base resin, and used a bisphenol-based unsaturated polyester resin with particularly excellent hot water resistance as the transparent resin layer (0.4 to 0.6 mm thick) applied to the surface of the molded product. A test piece was prepared using polyester resin (hot water resistance 3000 hours) according to the prior art (US Pat. No. 3,396,067 mentioned above).On the other hand, both the base resin and the transparent resin layer on the surface were made of hot water resistant bisphenol unsaturated polyester resin. Test pieces were prepared using resin under the same conditions as before.Using these two types of test pieces,
While a continuous hot water test was carried out in 90℃ hot water, a continuous immersion test in room temperature water was also carried out. As a result of the hot water test, the test piece whose base resin was ortho-unsaturated polyester resin showed no change in the transparent resin layer on the surface after 40 hours, but the inner glass powder-filled resin layer changed. Due to the whitening, the appearance completely lost its transparency. On the other hand, a test piece using a hot water-resistant bisphenol unsaturated polyester resin as the base resin was also compared to a test piece using an ortho unsaturated polyester resin as the base after 60 hours, despite using a hot water resistant resin. In almost the same way, the transparency of the appearance was lost. No change was observed in any of the test pieces immersed in water at room temperature for 200 hours. In the above experiment, although the base resin layer was formed from two types of resins with completely different hot water resistance and chemical resistance, there was almost no difference in hot water resistance between the two test pieces.
In other words, in a base resin layer that contains a large amount of glass powder (using Ferro Fritz #3134 as shown in the prior art) as a filler, the difference in the hot water resistance of the resin used depends on the hot water resistance of the molded product. No difference appears. This suggests that the glass powder and hot water present in large amounts in the base resin (70 parts by weight of #3134 glass powder per 30 parts by weight of the resin shown in the prior art) are somehow involved in this phenomenon. Next, in order to investigate the difference in hot water resistance of molded products due to the difference in the properties of the glass used as a filler, we decided to use transparent pyrex, which has particularly excellent chemical resistance among commercially available glass products. Glass powder of the same grade as glass was crushed to pass through 100 meshes as a filler, and tested in the same manner as above using hot water-resistant bisphenol unsaturated polyester resin for both the base resin and the transparent resin layer on the surface. A piece was prepared and a hot water resistance test was conducted under the same conditions as described above. The test results showed a slight whitening in the appearance after 60 hours of exposure at 90°C, further whitening became stronger after 80 hours, and almost completely white and opaque after 100 hours, but the transparent resin layer on the surface No changes were observed. From the above experimental facts, it is necessary to use a base resin with extremely high hot water resistance, or
It has been found that by improving the chemical resistance of the glass powder used as a filler, the heat resistance of the molded product can be improved to some extent, but to this extent, it is difficult to improve the heat resistance of the molded product for practical purposes (at least 150 hours of continuous water treatment in hot water at 90°C). The performance must be such that almost no change is observed upon exposure)) is not sufficient. Based on the above experimental results and other facts, the inventors have deduced the most likely process for the progress of white opacity as follows. That is, hot water, which has become highly active at high temperatures, easily passes through the transparent resin layer on the surface and reaches the vicinity of the glass particles dispersed in the base resin. On the other hand, since glass particles inherently have a hydrophilic surface with high polarity, it is difficult to obtain high adhesive strength at the interface with a resin with low polarity. It is thought that there is a layer, and hot water that reaches the vicinity of the glass particles is drawn into this grain boundary layer due to the high polarity of the glass surface and erodes the glass surface. Hot water causes elution of glass components from the glass surface, which adds to the hydrolysis effect of the base resin, which accelerates interfacial peeling between the resin and the glass particle surface, making the entire molded product white and opaque. estimated that. In addition, after exposure to hot water, the moisture remaining in the base resin gradually evaporates, causing irregular refraction due to the "voids" created at the interface between the resin and the glass particles, which may affect the appearance of the molded product. The clarity worsens over time. Therefore, in order to improve the hot water resistance of the molded product, the inventors believe that it is most effective to completely bond the resin and the surface of the glass particles so that no grain boundary layer exists. As a result of various studies, they completed the present invention. That is, the gist of the first invention of the present application is that the oxide composition is SiO ₂ 40 to 65% by weight (hereinafter referred to as weight %), B ₂ O ₃ 10 to 30%, and one type of monovalent alkali metal oxide. or more, the total amount of one or more of divalent alkaline earth metal oxides and ZnO is 5-30%, Al ₂ O ₃ 0-15%, TiO ₂ 0
~10%, _ZrO2 0~10% with a total oxide composition of 100
% of glass powder is treated with a silane coupling agent having unsaturated double bonds in the molecule,
A thermosetting resin molded article having a transparent pattern, characterized in that the treated glass powder is used as a filler in a thermosetting resin having an unsaturated double bond, and the second invention is a thermosetting resin that forms a transparent resin layer containing no glass powder as a filler on the surface of the molded article of the first invention, has an essentially two-layer structure, and has a transparent pattern. It is a resin molded product. Next, reasons for limiting the scope of claims of the present invention will be described. As mentioned above, it is necessary to limit the oxide composition of the glass powder used as a filler. Improving the chemical resistance of glass leads to improving the hot water resistance of thermosetting resin molded products, and also improves the transparency of the molded products. This is to obtain a glass having a refractive index that almost matches the refractive index of the base resin used. The amount of SiO ₂ is set at 40 to 65% by weight because it is necessary to improve or maintain the chemical resistance of the glass.
The amount of B ₂ O ₃ is 10 to 30% by weight, the total amount of one or more monovalent alkali metal oxides is 5 to 20% by weight, and the total amount of one or more monovalent alkali metal oxides is 5 to 20% by weight.
The reason why the total amount of seeds or more is 5 to 30% by weight is necessary in order to obtain a glass with a refractive index suitable for imparting transparency to molded products filled with it, and to improve hot water resistance. from Al ₂ O ₃ , TiO ₂ ,
This is because the amount of ZrO ₂ is necessary to promote the above-mentioned properties of the glass. Next, it is necessary to treat the surface of the glass powder having the composition range mentioned above with a silane coupling agent having unsaturated double bonds in the molecule, so that the molded product has hot water resistance and chemical resistance that can withstand practical use. This is because it is necessary to obtain a bond between the surface of the glass particles and the resin to provide a bond. To explain this mechanism in more detail, (a) Reaction between a silane coupling agent having an unsaturated double bond in the molecule and the glass surface R―Si―(OR′) ₃ +3H ₂ O→ Silane compound in the air Water R―Si―(OH) ₃ +3R′OH↑ …(1) Alcohol R: For example, CH ₂ =CH-,

[Formula] R′: For example, -CH ₃ , -C ₂ H ₅ , etc. (b) Reaction between a silane coupling agent having an unsaturated double bond in the molecule and a thermosetting resin having an unsaturated double bond is crosslinked by radical polymerization during curing of the resin. To explain this more specifically, when molded products are rapidly cured, those without silane treatment will experience more pronounced whitening and deterioration of hot water resistance due to interfacial peeling than those treated with silane. It can be seen that it works extremely effectively to strengthen the solid-liquid interface. Although it can be inferred from this that the crosslinking reaction occurs, this will be explained next based on experimental results. Resin used: FG-283 (hot water resistant grade manufactured by Dainippon Ink Co., Ltd.) Surface layer resin FG-387 (high hot water resistant grade manufactured by Dainippon Ink Co., Ltd.) All sample glass powders used were equivalent to #3134 made by Ferro Co., Ltd. in the United States. The resin, surface layer resin, and molding method are all the same. [A] Use of untreated glass powder [B] Vinyltriethoxysilane (Shin-Etsu Chemical KBE)
-1003) Use of 0.1% treated glass powder (organic reactive group/ethylenic double bond) CH ₂ = CHSi (OC ₂ H ₅ ) ₃ [C] γ-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM-503) 0.1 % treated glass powder used (organic reactive group/ethylenic double bond) [D] β-(34epoxycycloxyl)ethyltrimethoxysilane (Shin-Etsu Chemical KBM-303) 0.1
% treated glass powder used (organic reactive group/epoxy group) [E] N-β (aminoethyl)γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical KBM-602)
Using 0.1% treated glass (organic reactive group/amino group) H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ Hot water test (97℃ 100 hours) results

[Table] From the above experimental results, it is recognized that silane coupling agents with ethylenic double bonds in their molecules are effective against unsaturated silane coupling agents in terms of hot water resistance. This confirms that a reaction occurs between the thermosetting resin having a double bond and the silane coupling agent having an unsaturated double bond. When glass powder treated with a silane coupling agent having unsaturated double bonds in the molecule is used as a filler, the reaction between the silane coupling agent and the glass surface occurs on the one hand, and the silane coupling agent on the other hand. The crosslinking reaction between the coupling agent and the thermosetting resin occurs almost simultaneously, and the two work together to firmly bond the interface between the glass particle surface and the resin, thereby preventing erosion of the interface by hot water. As described above, the present invention involves specifying the glass powder composition to give the molded product transparency, hot water resistance, and chemical resistance, and treatment with a specific silane coupling agent that has unsaturated double bonds in its molecules. The means together achieved the initial goal. Further, the excellent industrial advantages of the present invention can be realized by treating the surface of the glass powder used as a filler with a silane coupling agent having an unsaturated double bond in the molecule. That is, the curing of the molded article can be rapidly accelerated (by heating or increasing the amount of curing agent) during molding. When untreated glass powder is used as a filler, if hardening is accelerated rapidly during molding, strong stress will be generated internally due to the curing heat generation and curing shrinkage of the resin, resulting in peeling at the interface between the resin and the glass powder. This may cause the molded product to become white and opaque or cause cracks in the molded product. Therefore, it was necessary to take a sufficiently long time for curing. In this regard, according to the present invention, since the interface is sufficiently strengthened, rapid curing is possible by heating or increasing the amount of curing agent (for example, by using glass powder as a filler in an amount of about 70% of the total weight) When manufacturing a molded product with a diameter of 15 mm, using untreated glass powder would require several hours or more of curing time at room temperature in order to obtain a molded product with good transparency. If treated glass powder is used, heating at 60 to 80℃ will
Can be rapidly cured in ~40 minutes. ). Industrially, this is a truly revolutionary method, as it enables a significant reduction in the costs associated with the production process and significantly improves the hot water resistance and chemical resistance of the product. Next, as described in Claim 2 as a second invention, and as specifically described in Example 2, a transparent resin layer containing no glass powder as a filler is formed on the surface of the molded product. However, by essentially having a two-layer structure, the hot water resistance is further improved, and the appearance of the pattern embodied in claim 1 is further emphasized, which has the effect of improving the aesthetic appearance of the molded product. It is. As the thermosetting resin having unsaturated double bonds used as the base resin of the present invention, unsaturated polyester resin is the most common because of its physical and chemical properties, cost, workability, etc.
Regardless of the type, as long as it has an unsaturated double bond that has the ability to undergo radical polymerization with the unsaturated double bond present in the silane molecule, and has sufficient transparency after curing, depending on the use. It is applicable to all vinyl ester resins (epoxy acrylate resins), thermosetting acrylic resins, diallyl phthalate resins, etc. In addition, in the present invention, as a silane coupling agent having an unsaturated double bond in the molecule to treat the surface of glass powder, vinyltriethoxysilane is used.
CH ₂ = CHSi(OC ₂ H ₅ ) ₃ , vinyltris-β-methoxyethoxysilane CH ₂ = CHSi(OCH ₃ .
OC ₂ H ₅ ) ₃ , γ-methacryloxypropyltrimethoxysilane CH ₂ =C(CH ₃ )C(O)OC ₃ H ₆ Si
(OCH ₃ ) ₃ , etc., and the amount used is generally in the range of 0.01 to 0.5 parts by weight per 100 parts by weight of glass, but the particle size of the glass powder, degree of hot water resistance, cost, etc. The appropriate amount to be added is determined by taking this into consideration. Furthermore, the size of the surface-treated glass powder particles is determined to prevent coarse glass particles from protruding onto the surface of the molded product and to facilitate mixing with the resin.
It is preferable to pass the entire 80 meshes. In addition, the ratio of surface-treated glass powder added to the resin that passes through the entire 80 mesh depends on workability during molding, strength of the molded product,
The amount is preferably 40 to 80% by weight of the total amount including the resin, considering the state of the pattern. As described above, the present invention uses a thermosetting resin having unsaturated double bonds, and the surface of glass particles having the above-mentioned specific composition is treated with a silane coupling agent having unsaturated double bonds in the molecule. By adding treated glass powder as a filler, a strong chemical bond is created between the resin and the glass particle surface via the silane coupling agent that has unsaturated double bonds in the molecule, and the resin and glass To provide good dispersibility when mixing powders, to obtain thermosetting resin molded products with desired pattern and transparency, excellent hot water resistance, and strength with good workability. It was a success. Next, the effectiveness of the present invention will be clarified through specific examples, including comparison with products made by conventional methods. Example 1 (1) Production of glass powder for filler The oxide composition was 65% by weight of SiO ₂ (hereinafter referred to as % by weight), 12% of B ₂ O ₃ , 10% of Na ₂ O + K ₂ O, 11% of CaO,
Add 0.04 parts by weight of vinyltriethoxysilane [CH ₂ =CHSi(OC ₂ H ₅ ) ₃ ] (KBE-1003, manufactured by Shin-Etsu Chemical) to 100 parts by weight of glass containing ₂ % Al ₂ O 3 and grind the glass with a ball mill. After surface treating the powder, it is passed through 80 meshes and used as a filler. (2) Preparation of neutral compound 70 parts by weight of the glass powder to be treated prepared in (1) is added to 30 parts by weight of isophthalic acid-based unsaturated polyester resin (FG-283 manufactured by Dainippon Ink & Chemicals) containing a curing accelerator in advance. Add and mix well to make a neutral compound. (3) Preparation of toner for patterning Add 30 parts by weight of isophthalic acid-based unsaturated polyester resin (FG-283 mentioned above) containing a curing accelerator in advance to rutile-type titanium oxide (R-820 manufactured by Ishihara Sangyo Co., Ltd.)
Add 30 parts by weight and 40 parts by weight of barium sulfate (first grade industrial reagent) and mix thoroughly to make a white toner, and add the same isophthalic acid-based unsaturated polyester resin.
30 parts by weight of black iron oxide (BL-500 manufactured by Titan Industries)
30 parts by weight, calcium carbonate (Nitto Funka NS-
100) Add 40 parts by weight and mix thoroughly to make a black toner. (4) Molding Prepare a plate molding mold, approximately 30% of the planned product weight.
Add an appropriate amount of curing agent to a neutral compound corresponding to , stir it, and then pour it evenly into a mold, and thoroughly defoam by applying vibration to the entire mold. Next, pour the white and black toner prepared earlier over the entire surface so that the desired pattern appears, and poke deep and shallow spatulas into the compound so that the toner and compound form irregular or striped patterns in some areas. After molding and curing, apply toner to the spatula so that a fine line pattern will appear on the surface, and plunge it deeply into the compound to draw a line, then add the remaining compound to the desired weight of the product. Pour some more and vibrate the mold for about 5 minutes to defoam. After degassing is complete, place the mold in a drying oven at 60 to 70℃ for approximately 20 minutes.
The mixture was cured by heating for a minute, cooled, and demolded to obtain a marble-like molded plate. (5) Hot water resistance test A 13cm square test piece was cut out from the molded plate obtained in (4) and placed in a patch-type hot water tester.The surface was exposed to 90°C hot water and the hot water test was continued for 200 hours. When the test was carried out, the test piece had a very slight yellow tinge after the test, but no whitening that would impede transparency was observed at all. Example 2 (1) Manufacture of glass powder for filler Same composition as Fritz #3134 of Ferro Co., Ltd. ["Ceramics for Pottery" by F., H. Norton]
(F.H. Norton: "Ceramic for the artist"
SiO ₂ 46.5% by weight (hereinafter referred to as weight%) B ₂ O ₃ 23% Na _{2 O} 10.5%
A glass containing 20% CaO was synthesized. (a) Add γ-methacroxypropyltrimethoxysilane [CH ₂ =C
( _CH3 )C(O) _OC3H6Si ( _OCH3 ) ₃ (KBM-503 manufactured by Shin-Etsu Chemical)] was added, and the surface was treated while being ground in _a ball mill, and then passed through an 80-mesh mesh. The obtained glass powder is called [A powder], (b) The glass powder obtained by crushing the same glass as in (a) in a ball mill and passing it through 80 meshes is called [B powder], and [A powder]
[Powder B] Two types of glass powders are used as thermosetting resin fillers. (2) Preparation of neutral compound Prepare 40 parts by weight of highly heat-resistant water-resistant bisphenol-based unsaturated polyester resin (FG-387 manufactured by Dainippon Ink Chemical Co., Ltd.) in two containers and add it to the mixture. Add 60 parts by weight of each of [A powder] and [B powder] prepared in (1) and mix thoroughly to obtain a neutral compound [A compound] and [B compound] containing [A powder] and [B powder] respectively. I got it. (3) Preparation of molds and formation of transparent resin layer Prepare two molds for plate molding, prepare the mold surfaces thoroughly, and apply mold release agent. Next, add a curing accelerator and curing agent to the bisphenol-based unsaturated polyester resin (FG-387), stir well, and spray it onto the mold surface as evenly as possible to a thickness of about 0.4 mm, and then cure thoroughly. . (4) Molding After adding an appropriate amount of curing agent to [Compound A] and [Compound B] prepared in (2) and stirring, pour each product separately into two molds by the estimated weight of the product and mold for about 5 minutes. Add vibration to defoam well. Next, the mold was placed in a drying oven at 60 to 70°C and heated to harden for about 20 minutes, cooled, and demolded to obtain plate-like marble-like molded plates [molded plate A] and [molded plate B]. (5) Hot water resistance test [A powder] containing [A powder] obtained in (4)
A test piece of 13 cm square was cut out from each of the molded plate] and the molded plate B containing the B powder, and subjected to a continuous hot water test at 90°C using a patch-type hot water tester.

[Table] A slight whitening phenomenon is observed even before the test.

[Table] Time *2: 〓A molded plate〓 is 200 hours,〓B molded plate〓 is 160 hours
time
The hot water resistance test results for both of the above are attached as reference photos. The upper part of the photo is the A molded plate, and the lower part is the B molded plate. Example 3 (1) Production of glass powder as filler The oxide composition is 60% by weight of SiO ₂ (hereinafter referred to as % by weight), 25% of B ₂ O ₃ , 5% of Na ₂ O, 5% of CaO, and 5% of Al ₂ O ₃ Vinyltris-β-methoxyethoxysilane [CH ₂ = CHSi (OCH ₃ .
0.1 part by weight of OC ₂ H ₅ ) ₃ ] (KBC1003 manufactured by Shin-Etsu Chemical Co., Ltd.) is added, the surface is treated while being ground in a ball mill, and the glass powder to be treated is used as a filler by passing it through an 80-mesh mesh. (2) Preparation of neutral compound 40 parts by weight of epoxy acrylate resin (Lipoxy R-802 manufactured by Showa Kobunshi Co., Ltd.), 60 parts by weight of the glass powder to be treated prepared in (1), and 0.01 parts by weight of phthalocyanine blue toner (pigment content 30%) Add parts by weight and appropriate amount of curing accelerator and mix well to prepare a pale blue neutral compound. (3) Preparation of toner for patterning Epoxy acrylate resin (R-802 mentioned above)
30 parts by weight, calcium carbonate (NS-100 mentioned above) 40
Parts by weight, inorganic green pigment (Nippon Ferro NV-
11633) Add an appropriate amount of curing accelerator to 30 parts by weight and mix well to make a green toner. (4) Molding Prepare a mold for molding a plate, add an appropriate amount of curing agent to the neutral compound, stir it, then uniformly pour about 30% of the planned weight of the product into it, and then add vibration to thoroughly defoam. After defoaming is complete, pour in the toner prepared in (3) so that the desired pattern appears, stir with a spatula so that the toner and compound are mixed irregularly, then pour in more compound to reach the planned weight of the product. Vibrate for about 5 minutes to defoam. Then 70-80℃
The mold was placed in a drying oven for about 20 minutes, heated and cured, cooled, and removed from the mold to obtain an onyx-like molded plate with a light blue-green pattern. (5) Hot water resistance test A 13 mm square test piece was cut out from the molded plate obtained in (4) and subjected to a hot water test at 90°C for 200 hours continuously.The test surface was slightly yellow. However, no whitening or opacification occurred. As is clear from the above examples, in order to significantly improve the hot water resistance of the molded product and not to impair the transparency of the pattern, a thermosetting resin filler having unsaturated double bonds is used. The present invention, which is characterized by using a glass powder of a specific composition whose surface is treated with a silane coupling agent having an unsaturated double bond in the molecule, is novel and has extremely large industrial effects. .

Claims (1)

[Claims] 1. Oxide composition SiO ₂ 40 to 65% by weight (hereinafter referred to as weight %), B ₂ O ₃ 10 to 30%, and the total amount of one or more monovalent alkali metal oxides is 5. -20%, total amount of one or more of divalent alkaline earth metal oxides and ZnO is 5-30%, Al ₂ O ₃ 0-15%, TiO ₂ 0
~10%, _ZrO2 0~10% with a total oxide composition of 100
% of glass powder is treated with a silane coupling agent having unsaturated double bonds in the molecule,
A thermosetting resin molded article having a transparent pattern, characterized in that the treated glass powder is used as a filler in a thermosetting resin having unsaturated double bonds. 2 Oxide composition SiO ₂ 40 to 65% by weight (hereinafter referred to as weight %), B ₂ O ₃ 10 to 30%, total amount of one or more monovalent alkali metal oxides 5 to 20%, divalent The total amount of one or more of alkaline earth metal oxides and ZnO is 5 to 30%, Al ₂ O ₃ 0 to 15%, TiO ₂ 0
~10%, _ZrO2 0~10% with a total oxide composition of 100
% of glass powder is treated with a silane coupling agent having unsaturated double bonds in the molecule,
The glass powder to be treated is used as a filler in a thermosetting resin having unsaturated double bonds, and the surface of a thermosetting resin molded product having a transparent pattern does not contain glass powder as a filler. A thermosetting resin molded article having an essentially two-layer structure and having a transparent pattern, characterized by forming a transparent resin layer.