In-mold coated body

Abstract

To provide a molded coated body with excellent appearance. [Solution] An in-mold coated body 1 comprising a resin base 2 and a coating portion 3 formed by RIM molding on the base 2, wherein the coating portion 3 comprises a coating main body portion 31 of constant thickness located in the center, a coating outer edge portion 32 of constant thickness including the outer edge and thinner than the coating main body portion 31, and a coating gradual thickness portion 33 connecting the coating main body portion 31 and the coating outer edge portion 32, and gradually decreasing in thickness from the coating main body portion 31 side to the coating outer edge portion 32 side, wherein the width a of the coating outer edge portion 32 is in the range of 5 to 50 mm, the thickness b of the coating outer edge portion 32 is in the range of 0.05 to 0.4 mm, the thickness c of the coating main body portion 31 is in the range of 0.1 to 3 mm, and the width d of the coating gradual thickness portion 33 is in the range of 3 to 100 mm.

Description

Technical Field

[0006]

[0001] The present invention relates to an in-mold coating body in which a coating portion formed by RIM molding is formed on a resin substrate.

Background Art

[0002] RIM molding is a kind of molding method for molding resin, and is an abbreviation of Reaction Injection Molding. In RIM molding, a polymer molding material is obtained by injecting two or more kinds of fluid reactive materials into a mold while rapidly reacting them in the mold. Unlike general injection molding in which a fluid resin material is directly injected into a mold, the fluid reactive material used in RIM molding has a relatively low molecular weight and low viscosity.

[0003] If such a coating portion formed by RIM molding is formed on a resin substrate, there is a possibility that a homogeneous coating portion can be easily formed at a desired thickness as compared with the case where the coating portion is formed by painting on the substrate.

[0004] Conventionally, various methods have been proposed as methods for molding a coating portion on a resin substrate. For example, Patent Document 1 proposes a technique for molding a coating portion by slightly opening a mold in which a substrate is molded and injecting a coating agent into the gap. By applying such a technique, it may be possible to form a coating portion formed by RIM molding on a resin substrate.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As mentioned earlier, the molding materials used in RIM molding, i.e., fluid reactive materials, are relatively low molecular weight and low viscosity. Such molding materials have high fluidity and behave differently during molding than typical injection molding resin materials.

[0007] Therefore, simply applying injection molding technology, such as that described in Patent Document 1, to RIM molding may not yield a coating with a superior appearance.

[0008] In other words, when attempting to form a coating on a resin substrate by RIM molding using a conventional mold molding method such as that described in Patent Document 1, problems arose in that air bubbles would form in the coating or streaky irregularities would form on the surface of the coating, resulting in an undesirable appearance.

[0009] Therefore, there is a need for in-mold coated bodies, in which a coating portion is formed by RIM molding on a resin substrate, that have excellent appearance.

[0010] This invention has been made in view of the above circumstances, and aims to solve the problem of providing a molded coated body with excellent appearance. [Means for solving the problem]

[0011] The in-mold coated body of the present invention, which solves the above problems, is It comprises a resin substrate and a coating portion formed by RIM molding on the substrate, The covering portion comprises a covering body portion of constant thickness located in the center, a covering outer edge portion of constant thickness which includes the outer edge and is thinner than the covering body portion, and a covering portion of gradually decreasing thickness which connects the covering body portion and the covering outer edge portion and gradually decreases in thickness from the covering body portion side toward the covering outer edge portion side. The width a of the outer edge of the covering is in the range of 5 to 50 mm. The thickness b of the outer edge of the coating is in the range of 0.05 to 0.4 mm. The thickness c of the aforementioned covering body is in the range of 0.1 to 3 mm. The width d of the coating's gradually changing portion is in the range of 3 to 100 mm, and it is an in-mold coated body. [Effects of the Invention]

[0012] The in-mold coated body of the present invention has excellent appearance. [Brief explanation of the drawing]

[0013] [Figure 1] This is an explanatory diagram illustrating the in-mold coated body of Example 1. [Figure 2] This is a schematic explanatory diagram showing how the in-mold coated body of Example 1 is cut at positions AA, BB, CC, and DD in Figure 1. [Figure 3] This is a schematic diagram illustrating the cavity for RIM molding of the coating portion in the in-mold coated body of Example 1. [Figure 4] This is an explanatory diagram illustrating the dimensions of each part of the in-mold coated body of Example 1. [Figure 5] This is an explanatory diagram illustrating the appearance of the in-mold coated body of Example 1 immediately after molding. [Figure 6] This is a schematic explanatory diagram showing the in-mold coated body of Example 1 immediately after molding, when cut at position EE in Figure 5. [Figure 7] This is a schematic explanatory diagram showing the in-mold coated body of Example 1 immediately after molding, when cut at the FF position in Figure 5. [Figure 8] This is a schematic diagram illustrating the process of RIM molding of the coating portion in the in-mold coated body of Example 1. [Figure 9] This is a schematic diagram illustrating the process of RIM molding of the coating portion in the in-mold coated body of Example 1. [Figure 10] This is a schematic diagram illustrating the process of RIM molding of the coating portion in the in-mold coated body of Example 1. [Figure 11] It is an explanatory drawing schematically explaining the appearance of the in-mold coating body of a modification immediately after molding. [Figure 12] It is an explanatory drawing schematically showing a state where the in-mold coating body of a modification immediately after molding is cut at the E-E position in FIG. 11. [Figure 13] It is an explanatory drawing schematically showing a state where the in-mold coating body of a modification immediately after molding is cut at the F-F position in FIG. 11. [Figure 14] It is an explanatory drawing schematically explaining a state where the coating part in the in-mold coating body of the comparative example is being RIM molded. [Figure 15] It is an explanatory drawing schematically explaining a state where the coating part in the in-mold coating body of the comparative example is being RIM molded.

Mode for Carrying Out the Invention

[0014] The inventor of the present invention has earnestly conducted research to manufacture an in-mold coating body in which a coating part by RIM molding is formed on a resin base body and which has excellent appearance. And in the process, the inventor noticed the problems in manufacturing the conventional in-mold coating body.

[0015] Taking as an example the case of RIM molding a coating part with a constant thickness on a resin base body arranged in a mold as in the comparative example described later, the problems in manufacturing the conventional in-mold coating body will be explained.

[0016] When injecting a molding material into a cavity formed between a mold and a resin base body arranged in the mold at a predetermined speed, the molding material injected into the cavity through the injection port spreads in a direction away from the injection port in the cavity as shown in FIG. 14.

[0017] If the thickness of the coating to be molded is very thin, for example less than 1 mm, then the thickness of the cavity into which the coating is molded using RIM is also very thin. In this case, the molding material flowing within the cavity will have a flow velocity distribution downstream from the injection port, where the velocity is faster in the center and slower at the edges (Figures 14 and 15).

[0018] As previously mentioned, the molding material used in RIM molding has relatively low viscosity and high fluidity. Therefore, the molding material that flows through the cavity and reaches the mold surface is reflected by the mold surface and flows in the opposite direction to the initial flow direction (Figure 15). If the flow velocity difference of the molding material between the downstream central part and the end is excessive, as shown in Figure 15, the molding material that reaches the downstream central part will reflect off the mold surface and flow towards the end. As a result, at the downstream end, the molding material that flowed straight from the injection port and the molding material that has been reflected from the downstream central part merge. In the cavity, air remains near the confluence point between the two molding material flows, which is thought to cause defects in appearance such as the formation of air bubbles in the coating or the appearance of wavy air marks on the surface of the coating.

[0019] In the downstream area described above, one of the reasons why the flow velocity of the molding material is slower at the ends than in the center is that the distance from the injection port is longer at the downstream ends than in the downstream center, that is, the flow path from the injection port to the downstream ends is longer. Another contributing factor is the turbulence in the flow of the molding material due to reflection of the molding material from the mold surface, as described above. Furthermore, the longer the flow path of the molding material, the greater the frictional resistance between the molding material and the mold surface or substrate surface.

[0020] In typical resin injection molding dies, a common method to eliminate the difference in flow velocity of the molding material between the downstream end and the downstream center is to increase the cross-sectional area of ​​the flow path in the cavity to reduce flow resistance. However, as previously mentioned, the molding material used in RIM molding has low viscosity, so increasing the cross-sectional area of ​​the flow path reduces the flow velocity of the molding material (Bernoulli's principle). This increases the flow velocity difference within the cavity, which increases the backflow velocity of the molding material reflected from the mold surface and increases its flow rate. Therefore, even in this case, the problem of poor appearance of the coated area due to air bubbles and air marks, as described above, remains unresolved.

[0021] Furthermore, simply narrowing the channel cross-sectional area uniformly increases the influence of the frictional resistance mentioned above, making it difficult to fill the cavity with the molding material before the reaction of the molding material is complete, i.e., before the effect is achieved.

[0022] As another measure, for example, it is conceivable to reduce the occurrence of bubbles and air marks in the coating by providing a void cavity outside the cavity to allow air to escape, thereby pushing the air inside the cavity into the void cavity. However, even in this case, depending on the size of the waste cavity, the size of the connecting passage between the cavity and the waste cavity, and the position of the connecting passage relative to the cavity, it may be difficult to sufficiently push the air inside the cavity into the waste cavity. It is thought that increasing the size of the waste cavity and increasing the amount of molding material injected into the cavity would make it possible to push all or most of the air inside the cavity into the waste cavity. However, in this case, the yield of the molding material deteriorates, so this embodiment is not desirable for the manufacture of in-mold coated bodies.

[0023] The inventors of this invention aimed to eliminate or suppress appearance defects in in-mold coated bodies in which a coating portion is formed by RIM molding on a resin substrate, and to produce in-mold coated bodies with superior appearance, by bringing the flow velocity of the molding material at the downstream end of the cavity closer to the flow velocity of the molding material at the downstream central part, and thus completed the present invention.

[0024] The in-mold coated body of the present invention comprises a resin substrate and a coating portion formed by RIM molding on the substrate. Furthermore, the coating portion of the in-mold coated body of the present invention comprises a coating body portion of constant thickness located in the center, a coating outer edge portion of constant thickness which includes the outer edge and is thinner than the coating body portion, and a coating gradual change portion which connects the coating body portion and the coating outer edge portion and gradually decreases in thickness from the coating body portion side toward the coating outer edge portion side. The dimensions of each part of the covering are as follows: (a) The width a of the outer edge of the covering is in the range of 5 to 50 mm. (b) The thickness b of the outer edge of the covering is in the range of 0.05 to 0.4 mm. (c) The thickness c of the covering body is in the range of 0.1 to 3 mm. (d) The width d of the covering deformation portion is in the range of 3 to 100 mm.

[0025] The inventors of the present invention conceived of making the thickness of the coating portion in an in-mold coated body different for each part of the coating portion.

[0026] In other words, the thickness of the central part of the in-mold coated body (the main coating portion) was kept constant, while the thickness of the portion near the outer edge of the in-mold coated body (the outer coating edge portion) was made thinner than that of the main coating portion. Furthermore, the thickness of the portion connecting the main coating portion and the outer coating edge portion (the gradually changing coating portion) was made to gradually decrease from the main coating portion side towards the outer coating edge side.

[0027] Hereinafter, as necessary, the region of the cavity that forms the covering portion in which the covering body portion is formed will be referred to as the main body forming region, the region in which the covering deformation portion is formed will be referred to as the deformation portion forming region, and the region in which the covering outer edge portion is formed will be referred to as the outer edge forming region.

[0028] By designing the thickness of each part of the coating in this way, the flow velocity of the molding material within the cavity is fast in the region where the main body of the coating is formed, and gradually slows down from the region where the coating's gradual deformation is formed towards the region where the coating's outer edge is formed. Therefore, the time required for the molding material to reflect off the mold surface after passing through the region where the coating's outer edge is formed within the cavity is relatively long, and the difference in the flow velocity of the molding material between the downstream end and the downstream center of the cavity becomes small.

[0029] Even when the relationship between the thickness of the main body, the outer edge, and the gradually changing thickness of the coating in an in-mold coated body is set as described above, if the thickness of each part is excessive or insufficient, or if the width of each part is excessive or insufficient, the effect of reducing the flow velocity difference of the molding material between the downstream end and the downstream center may not be fully realized. In such cases, it is difficult to eliminate the appearance defects of the in-mold coated body.

[0030] In the in-mold coated body of the present invention, by setting the width a of the outer edge of the coating, the thickness b of the outer edge of the coating, the thickness c of the main body of the coating, and the width d of the gradually changing portion of the coating as described in (a) to (d) above, the effect of reducing the flow velocity difference of the molding material between the downstream end and the downstream central part is fully realized. As a result, it becomes possible to manufacture an in-mold coated body with excellent appearance.

[0031] The in-mold coated body of the present invention will be described below for each of its constituent elements. Unless otherwise specified, the numerical range "x~y" described herein includes the lower limit x and the upper limit y. Furthermore, new numerical ranges can be constructed by arbitrarily combining these upper and lower limits, as well as the numerical values ​​listed in the examples. Additionally, any numerical values ​​selected from any of the above numerical ranges can be used as the upper and lower limits of a new numerical range.

[0032] The use, shape, and size of the in-mold coated body of the present invention are not particularly limited, but the effect of suppressing the above-mentioned appearance defects is particularly pronounced when it is large. Specifically, the effect of suppressing the above-mentioned appearance defects is particularly pronounced when the longitudinal size of the in-mold coated body of the present invention is 500 mm or more, 700 mm or more, or 1000 mm or more. The in-mold coated body of the present invention may be embodied, for example, as a vehicle bumper, roof, door, etc.

[0033] The in-mold coated body of the present invention comprises a resin substrate and a coating portion formed by RIM molding on the substrate.

[0034] The base material may include a resin, but the amount and type of the resin are not particularly limited. For example, the base material may include reinforcing fibers such as glass fiber or carbon fiber in addition to the resin, or it may include other fillers, reinforcing agents, additives, etc. The base material is preferably one that is compatible with molding materials for RIM molding. For example, it is particularly preferable to use ABS (acrylonitrile-butadiene-styrene copolymer), AES (acrylonitrile-ethylene propylene rubber-styrene copolymer), ASA (acrylonitrile-styrene-acrylic acid ester copolymer), etc., either alone or in combination of two or more, as the resin.

[0035] While there are no particular limitations on the shape of the substrate, as mentioned above, the in-mold coated body of the present invention is preferably large, and considering this, the substrate is particularly preferably 500 mm or more, 700 mm or more, or 1000 mm or more in its longitudinal direction. There is no upper limit to the longitudinal length of the base, but possible examples of upper limits include 3500mm or less, 3000mm or less, or 2500mm or less.

[0036] The thickness of the substrate is not particularly limited, but it is preferable that it be thicker than the coating portion. Examples of specific substrate thicknesses include 0.7 mm or more, 1.0 mm or more, or 1.5 mm or more. Alternatively, the thickness of the substrate may be 1.5 times or more, 5 times or more, or 10 times or more the thickness of the main body of the coating portion. There is no specific upper limit on the thickness of the substrate, but examples include 10mm or less, 7mm or less, or 5mm or less.

[0037] The coated portion is formed by RIM molding, and the material used for it may be two or more reactive materials that are RIM moldable. The polymer molding material obtained by the reaction of these reactive materials can be called the material for the coated portion. Furthermore, the two or more reactive materials that are the raw materials for this molding material can be called the raw materials for the coated portion.

[0038] The covering portion may be a foam with multiple air bubbles, or it may be a solid without air bubbles.

[0039] The molding material for the covering portion may be a thermosetting resin or a thermoplastic resin. Examples of such molding materials include, but are not limited to, polyurethane, polyurea, polyisocyanurate, polyester, polyphenol, polyepoxide, and polyamide (nylon 6).

[0040] As the raw material for the coating portion, i.e., the reactive material, any raw material for a molding material capable of forming the above-mentioned coating portion may be used. As an example of a reactive material, if the material of the coating is polyurethane, then a combination of a first material containing a polyol and a second material containing an isocyanate can be selected as the reactive material. Furthermore, if the coating material is polyamide, for example, a combination of a first material containing a cyclic lactam such as ε-caprolactam and a polymerization catalyst, and a second material containing a cyclic lactam, a polymerization accelerator, and an epoxy component can be selected as the reactive material. Furthermore, if the coating material is polyester, for example, a combination of a first material containing cyclic carbonates and cyclic esters, and a second material containing polymerization catalysts such as metal oxides and organometallic compounds can be selected as the reactive material. Furthermore, the combination of the reactive materials, the first material and the second material, is not limited to those described above. Moreover, even with the above-described combination of the first material and the second material, the first material and / or the second material may contain other reactive materials or additives not mentioned above.

[0041] The viscosity of the molding material for the coating portion, that is, the combination of the two or more reactive materials described above, is preferably 1000 Pa·s or less immediately after the start of the reaction.

[0042] The coating portion of the in-mold coated body of the present invention comprises a coating body portion of constant thickness located in the center, a coating outer edge portion of constant thickness which includes the outer edge and is thinner than the coating body portion, and a coating gradual change portion which connects the coating body portion and the coating outer edge portion and whose thickness gradually decreases from the coating body portion side toward the coating outer edge portion side.

[0043] The term "center" here refers not to the center in the thickness direction, but to the center in the longitudinal direction and the direction perpendicular to the longitudinal direction. Furthermore, the term "center" here does not refer to the center in an absolute dimensional sense, but rather to the center in relation to the outer edge of the covering.

[0044] Furthermore, "constant thickness" here does not refer only to items with perfectly constant thickness, but rather allows for an error of approximately ±5% in length.

[0045] In the coating portion of the in-mold coated body of the present invention, the thickness of the outer edge of the coating is thinner than the thickness of the main body of the coating. The thickness c of the main body of the coating is in the range of 0.1 to 3 mm, and the thickness b of the outer edge of the coating is in the range of 0.05 to 0.4 mm. The thickness of the gradually changing portion of the coating should gradually decrease from the main body of the coating to the outer edge of the coating, and may change linearly or in steps.

[0046] The suitable ranges of the thickness c of the coated main body part and the thickness b of the coated outer edge part can be expressed not only by the above absolute numerical values but also by the relative relationship between the thickness c of the coated main body part and the thickness b of the coated outer edge part. In terms of the relative relationship, it is preferable that the thickness b of the coated outer edge part and the thickness c of the coated main body part satisfy the relationship of 1.2 < (c / b) < 10.

[0047] Also, the width a of the coated outer edge part in the coated part is within the range of 5 to 50 mm, and the width d of the coated creep part is within the range of 3 to 100 mm. The width of the coated outer edge part and the width of the coated creep part mentioned here mean the lengths of the respective parts in the radial inner - outer direction in the coated part.

[0048] The suitable range of the width d of the coated creep part can be expressed not only by the above absolute numerical values but also by the relative relationship between the width d of the coated creep part, the thickness b of the coated outer edge part, and the thickness c of the coated main body part. In terms of the relative relationship, it is preferable that the thickness b of the coated outer edge part, the thickness c of the coated main body part, and the width d of the coated creep part satisfy the relationship of 2×(c / b) < d. <000​​​​​​​​​​​​​Figure 1 is a schematic diagram illustrating the in-mold coated body of Example 1. Figure 2 is a schematic diagram showing the in-mold coated body of Example 1 cut at positions AA, BB, CC, and DD in Figure 1. Figure 3 is a schematic diagram illustrating the cavity for RIM molding of the coating portion in the in-mold coated body of Example 1. Figure 4 is a schematic diagram illustrating the dimensions of each part in the in-mold coated body of Example 1. Figure 5 is a schematic diagram illustrating the appearance of the in-mold coated body of Example 1 immediately after molding. Figure 6 is a schematic diagram showing the in-mold coated body of Example 1 cut at position EE in Figure 5 immediately after molding. Figure 7 is a schematic diagram showing the in-mold coated body of Example 1 cut at position FF in Figure 5 immediately after molding. Figures 8 to 10 are schematic diagrams illustrating the RIM molding process of the coating portion in the in-mold coated body of Example 1. In addition, Figure 5 shows the in-mold coated body in a more realistic shape compared to Figures 1 and 8-10.

[0052] As shown in Figure 2, the in-mold coated body 1 of Example 1 has a substrate 2 and a coating portion 3. The base 2 is made of ABS plastic, and the covering part 3 is made of polyurethane.

[0053] In the in-mold coated body 1 of Example 1, its longitudinal length is approximately 1500 mm, and its orthogonal length perpendicular to the longitudinal direction is approximately 300 mm. The longitudinal and orthogonal lengths of the substrate 2 are similar. Furthermore, the thickness of the substrate 2 is approximately 3.0 mm.

[0054] The covering portion 3 is RIM molded on the base body 2. As shown in Figure 1, the covering portion 3 has a covering body portion 31, a covering outer edge portion 32, and a covering deformation portion 33. The surface of the covering portion 3, that is, the surface of the covering portion 3 opposite to the base body 2, is a flat surface.

[0055] The coated main body portion 31 is a portion located at the center in the longitudinal direction and the orthogonal direction in the coating portion 3. The thickness c of the coated main body portion 31 shown in FIG. 4 is about 0.4 mm, and the thickness c of the coated main body portion 31 is constant as shown in FIG. 2.

[0056] The coated outer edge portion 32 is a portion of the coating portion 3 that is radially outside the coated main body portion 31, and also includes the outer edge of the coating portion 3. The thickness b of the coated outer edge portion 32 shown in FIG. 4 is about 0.25 mm, which is thinner than the thickness c of the coated main body portion 31. As shown in FIG. 2, the thickness b of the coated outer edge portion 32 is also constant. <000​​​​​​​​​​​​​​​​​​​​​​​​

[0062] The cavity 80 has a shape that is substantially the same as that of the coating portion 3. Furthermore, the substrate 2 that forms part of the cavity 80 is the same as the substrate 2 in the in-mold coated body 1. Therefore, the shape of the coating portion 3 in the in-mold coated body 1 shown in Figures 6 to 8 can be interpreted as the shape of the cavity 80.

[0063] The cavity 80 described above is further equipped with a gate 85, which serves as an injection port for the molding material, and a sewage cavity (not shown in the diagram), which serves as an escape route for air inside the cavity 80.

[0064] As shown in Figure 5, the runner portion 70, i.e., the hardened portion of the molding material remaining in the gate (not shown), is located on one end of the covering portion 3, i.e., the cavity 80, and is connected to the cavity 80. The discard tab 71, i.e., the hardened portion of the molding material remaining in the discard cavity (not shown), is located on the other end of the covering portion 3, i.e., the cavity 80, and is connected to the cavity 80.

[0065] As shown in Figures 6 and 7, the gate 85 and the waste cavity (not shown) extend in a direction perpendicular to the longitudinal direction of the cavity 80 and intersects with the thickness direction of the cavity 80, and are connected to the cavity 80 in a substantially L-shape.

[0066] As shown in Figure 3, the cavity 80 has a main body molding region S1 for molding the main body 31, a deformation region S2 for molding the deformation region 33 of the covering, and an outer edge molding region S3 for molding the outer edge of the covering 32.

[0067] When forming the coating portion 3, first, a first material containing a polyol, which is a reactive material, and a second material containing an isocyanate are mixed, and the resulting fluid molding material 5 is injected into the cavity 80 described above. At this time, as shown in Figure 8, the molding material 5 flows through the gate 85 into the outer edge molding region S3 located near the gate 85. The injection speed of the molding material 5 into the cavity 80 is such that the injection into the cavity 80 is completed within the curing time of the molding material 5, specifically, within 0.5 seconds to 4.0 seconds.

[0068] The molding material 5 that has passed through the outer edge molding region S3 mainly flows into the gradual deformation molding region S2 adjacent to the outer edge molding region S3, and then flows through the gradual deformation molding region S2 into the main body molding region S1. The material then flows through the main body molding region S1 from the gate 85 side in the longitudinal direction of the cavity 80, i.e., from one end to the other end. The thickness of the main body molding region S1 is approximately constant, and the flow velocity of the molding material 5 flowing through the main body molding region S1 is also approximately constant.

[0069] The molding material 5 that has passed through the main body molding region S1 flows into the gradual deformation region S2 adjacent to the main body molding region S1 further downstream in its flow direction, and then flows into the outer edge molding region S3 adjacent to the gradual deformation region S2.

[0070] The thickness of the cavity 80 gradually decreases in the gradually changing molding region S2 towards the outer edge molding region S3. The outer edge molding region S3 is the thinnest part of the cavity 80, and is a region where the frictional resistance between the molding material 5 and the mold surface of the cavity 80 and the surface of the base 2 has a strong influence. For this reason, as the molding material 5 flows from the gradually changing molding region S2 towards the outer edge molding region S3, the flow velocity of the molding material 5 decreases. Also, because the frictional resistance increases towards the outer edge molding region S3, as shown by the arrow in Figure 9, the flow direction of the molding material 5 flowing from the gradually changing molding region S2 towards the outer edge molding region S3 is bent so that the angle becomes slightly blunt towards the downstream side of the cavity 80.

[0071] On the other hand, as previously described, the thickness of the main body molding region S1 is approximately constant, and the flow velocity of the molding material 5 flowing through the main body molding region S1 is also approximately constant. Therefore, the molding material 5 flows through the main body molding region S1, prioritizing the gradual deformation region S2 and the outer edge molding region S3 of the cavity 80.

[0072] Furthermore, downstream of the cavity 80, similarly to the above, the flow velocity of the molding material 5 decreases as it flows from the main body molding region S1 towards the outer edge molding region S3. As a result, it takes time for the molding material 5 to reach the wall surface of the cavity 80, which suppresses the reflection of the molding material 5 from the mold surface, and also suppresses the turbulence caused by the reflected molding material 5 (Figures 9 and 10).

[0073] As a result, when molding the coating portion 3 in the in-mold coated body 1 of Example 1, it becomes possible to bring the flow velocity of the molding material 5 at the downstream end of the cavity 80 closer to the flow velocity of the molding material 5 at the downstream central part, and also suppresses the entrapment of air into the molding material 5.

[0074] Furthermore, a sacrificial cavity (not shown) is provided at the other end of the cavity 80 in the longitudinal direction, i.e., the downstream side. A portion of the molding material 5 that reaches the downstream end in the longitudinal direction within the cavity 80 flows into the sacrificial cavity, entraining any remaining air in the cavity 80. Therefore, the entrainment of air into the molding material 5 within the cavity 80 is further reduced, and the appearance of the coating 3 molded in the cavity 80 is further improved.

[0075] As described above, the in-mold coated body 1 integrally includes a runner portion 70 made of molded material 5 remaining and hardened at the gate 85, and a waste tab 71 made of molded material 5 that has flowed into a waste cavity (not shown) and hardened. After molding, the runner portion 70 and the discard tab 71 were cut and removed at the positions indicated by the arrows in Figure 6 and Figure 7, respectively, to obtain the in-mold coated body 1 of Example 1.

[0076] According to the in-mold coated body 1 of Example 1, it is possible to bring the flow velocity of the molding material 5 at the downstream end of the cavity 80 during molding closer to the flow velocity of the molding material 5 at the downstream central part, and it is also possible to suppress air entrapment into the molding material 5. As a result, the in-mold coated body 1 of Example 1 obtained has an excellent appearance.

[0077] (modified version) The modified in-mold coated body is substantially the same as the in-mold coated body 1 of Example 1, except for the position of the runner portion and the discard tab relative to the coated portion. Figure 11 is an explanatory diagram schematically illustrating the appearance of the modified in-mold coated body immediately after molding. Figure 12 is an explanatory diagram schematically showing the modified in-mold coated body immediately after molding cut at position EE in Figure 11. Figure 13 is an explanatory diagram schematically showing the modified in-mold coated body immediately after molding cut at position FF in Figure 11.

[0078] As shown in Figure 11, in the modified in-mold coated body 1, similar to the in-mold coated body 1 of Example 1, the runner portion 70 is provided on one end side in the longitudinal direction of the coated portion 3, and the discard tab 71 is provided on the other end side in the longitudinal direction of the coated portion 3.

[0079] In the mold 8 for forming the coating portion 3 in the modified in-mold coated body 1, the gate 85 and the waste cavity (not shown) extend in the longitudinal direction of the cavity 80 and in the thickness direction of the cavity 80, and are connected to the cavity 80 in a stepped manner.

[0080] In this modified in-mold coated body 1, similar to the in-mold coated body 1 of Example 1, it is possible to bring the flow velocity of the molding material 5 at the downstream end of the cavity 80 during molding closer to the flow velocity of the molding material 5 at the downstream central part, and it is also possible to suppress the entrapment of air into the molding material 5. As a result, the modified in-mold coated body 1 also has an excellent appearance.

[0081] (Comparative example) The in-mold coated body of the comparative example is substantially the same as the in-mold coated body of Example 1, except that the thickness of the coated portion is approximately constant. Figures 14 and 15 are schematic diagrams illustrating the RIM molding process for the coating portion of the comparative example in-mold coated body.

[0082] As described above, the coating portion of the in-mold coated body in the comparative example has a substantially constant thickness. Therefore, it can be said that in the in-mold coated body of the comparative example, the coating portion consists only of the coating body.

[0083] The cavity 80 for forming this covering portion is also composed solely of the main body molding region S1. Therefore, as shown in Figure 14, the molding material 5 injected into the cavity 80 is injected directly into the main body molding region S1 via the gate 85 and flows downstream through the main body molding region S1. As shown in Figure 15, the molding material 5 collides with the mold surface of the mold, creating turbulence within the cavity 80. Furthermore, the flow velocity of the molding material 5 at the downstream end of the cavity 80 is slower than the flow velocity of the molding material 5 at the downstream center, and the difference in flow velocity is large. Consequently, air entrapment into the molding material 5 occurs within the cavity 80. As a result, the in-mold coated body 1 of the comparative example had an inferior appearance.

[0084] Although the present invention has been described above, it is not limited to the embodiments described above, and it is possible to implement the invention by appropriately extracting and combining the elements described in the embodiments, and to make various modifications without departing from the spirit of the present invention. Furthermore, the specification of this invention discloses not only the reference relationships of each claim as initially filed, but also a technical concept that appropriately combines the matters described in each claim. [Explanation of Symbols]

[0085] 1: In-mold coated body 2: Base 3: Covering part 31: Covering body 32: Covering deformation section 33: Outer edge of the covering a: Width of the outer edge of the covering b: Thickness of the outer edge of the covering c: Thickness of the main body of the covering d: Width of the gradually changing part of the covering

Claims

1. It comprises a resin substrate and a coating portion formed by RIM molding on the substrate, The covering portion comprises a covering body portion of constant thickness located in the center, a covering outer edge portion of constant thickness which includes the outer edge and is thinner than the covering body portion, and a covering portion of gradually decreasing thickness which connects the covering body portion and the covering outer edge portion and gradually decreases in thickness from the covering body portion side toward the covering outer edge portion side. The width a of the outer edge of the covering is in the range of 5 to 50 mm. The thickness b of the outer edge of the coating is in the range of 0.05 to 0.4 mm. The thickness c of the covering body is in the range of 0.1 to 3 mm. An in-mold coated body in which the width d of the coating's gradually changing portion is in the range of 3 to 100 mm.

2. The thickness b of the outer edge of the covering and the thickness c of the main body of the covering satisfy the relationship 1.2 < (c / b) < 10. The in-mold coated body according to claim 1, wherein the thickness b of the outer edge portion of the coating, the thickness c of the main body portion of the coating, and the width d of the gradually changing portion of the coating satisfy the relationship 2 × (c / b) < d.

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