WO2005046958A1

WO2005046958A1 - Method of in-mold coating

Info

Publication number: WO2005046958A1
Application number: PCT/JP2004/016988
Authority: WO
Inventors: Masaki Takeuchi
Original assignee: Rimtec Corporation
Priority date: 2003-11-17
Filing date: 2004-11-16
Publication date: 2005-05-26
Also published as: TW200533500A; JP4417912B2; JPWO2005046958A1

Abstract

A method of in-mold coating, comprising the reaction injection molding step of effecting reaction of a molding material consisting of a cycloolefin, a catalyst component and a catalyst activating component in a metal mold to thereby obtain a shaped item and the coat forming step of while immobilizing the shaped item in the metal mold by shaped item fixing means, injecting a coating agent in the metal mold and curing the same to thereby form a coat on the surface of the shaped item. In the provided in-mold coating method, a uniform coat can be formed with high reproducibility on not only the front of shaped item (11) close to coating agent injection port (3) but also corner portions (22) and lateral faces (23) of shaped item (11) remote from the coating agent injection port (3), to which getting around of the coating agent is difficult. Further, in the method, the shaped item can be easily set aside from the metal mold.

Description

Specification

Immono red coating method

Technical field

[0001] The present invention is applicable to automotive applications such as bumpers and air deflectors, construction equipment such as wheel loaders and power shovels, industrial machinery applications, leisure applications such as golf carts and game machines, and industrial applications such as medical equipment and chairs. The present invention relates to a method for in-mold coating of a reaction injection molded article which is frequently used.

Background art

[0002] Conventionally, a reaction injection molded product is obtained by polymerizing a monomer in a mold, cross-linking and molding, removing the molded product from the mold, spraying a coating agent, and baking and curing in a high-temperature furnace. It was covered. However, there was a disadvantage that the molded product was damaged or stained due to handling during the transfer of the molding process to the coating process. In this case, a process of sanding was required for repairing the wound, and a process of wiping or washing with an organic solvent or stone water was required for removing dirt.

In addition, there is a need to invest heavily in coating equipment. In other words, equipment is required to recover and regenerate a large amount of organic solvent used for washing molded articles and a large amount of organic solvent that is a component of the coating agent, and strict equipment management is required from the viewpoint of environmental safety. . In addition, a skilled technician was required to obtain a stable and beautiful coated surface.

As described above, the conventional coating method has various problems, and it has been desired to develop a coating method which is simpler, faster, more reliable, and more environmentally friendly.

[0003] As a method of improving these problems, an in-mold coating method has been proposed, and various studies have been made.

For example, Patent Document 1 discloses an in-mold coating method in which a temperature difference is provided between a cavity mold and a core mold, and a coating agent is injected from a high-temperature mold side, thereby improving the adhesiveness of the coating agent and a film forming effect. Have been tried. Further, in Patent Document 2, by providing a coating material injection port in a mold corresponding to a portion cut off after molding of a molded product or a portion where external force becomes invisible after product assembly, poor appearance and poor adhesion are reduced. Attempts have been made to reduce in-mold coating methods.

However, according to these conventional methods, when the molded product is a molded product obtained by reaction injection molding of a cyclic olefin, in the coating step, particularly, the coating of the side surface and the corner portion of the molded product where the coating agent is difficult to flow around is performed. There were problems such as insufficient coating and a lack of uniform film thickness.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-71345

Patent Document 2: JP-A-2003-11159

Disclosure of the invention

Problems to be solved by the invention

[0005] An object of the present invention is to provide a uniform and reproducible coating not only on the front surface of the molded product near the coating material injection port but also on the side surface and corner portion of the molded product where the coating material is hard to flow around. An object of the present invention is to provide an in-mold coating method capable of forming a film and easily removing a molded product from a mold. Means for solving the problem

[0006] The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, since the molded product obtained by reaction injection molding of cyclic olefin is hard, the molded product is formed by injection pressure of a coating agent in a coating process. When the product is tilted in the mold, the surface of the molded product can be seen through the coating (cured coating film) on the side or corner of the molded product, or the surface to be coated (hereinafter referred to as “design surface”). "). It was also found that film formation defects such as" peeling out "where the coating agent could not reach the part occurred and that the film thickness became uneven. Therefore, the molding material is subjected to reaction injection molding in a mold, the molding is fixed by means of molding fixing so that the molding is not powered by injection of the coating agent, and then the surface of the obtained molding is coated with the coating agent. The present invention was found to prevent poor coating formation on the side surfaces and corners of molded products where the coating agent is difficult to sneak around, even when the coating agent is far from the injection location, and that a coating film with a uniform film thickness can be obtained.

[0007] That is, according to the present invention,

A reaction injection molding step of reacting a molding material comprising a cyclic olefin, a catalyst component and a catalyst active component in a mold to obtain a molded product; A film forming step of injecting a covering agent into the mold and curing the molded product in a state where the molded product is fixed in the mold by molded product fixing means, and forming a film on the surface of the molded product; An in-mold coating method is provided.

The in-mold coating method in the present invention is a method in which a coating agent is injected into a mold without taking out the obtained molded article from the mold to form a film on the surface of the molded article. The molded article fixing means is not particularly limited as long as a molded article obtained by reaction injection molding in a mold can be fixed in the mold. Examples of the molded product fixing means include a concave portion or a convex portion provided on a mold; a molded product suction means provided on a mold; and the like. It is preferable that the concave portion or the convex portion provided in the mold has a slide mechanism. The molded article fixing means is an undercoat layer formed by in-mold coating.

Preferably, when a mold formed of a core mold and a cavity mold is used, and the surface of a molded article in contact with one of the core mold and the cavity mold is coated with a coating agent, The molded article fixing means is provided on either the core mold or the cavity mold.

Preferably, one of the core mold and the cavity mold is slightly opened relative to the other mold, and a coating is provided between the inner surface of the one mold and the molded article. A gap is formed so that a flow path for the agent can be secured, and the coating agent is injected into the gap.

Preferably, when a mold formed of a core mold and a cavity mold is used, and the surface of a molded article in contact with one of the core mold and the cavity mold is coated with a coating agent. The average surface temperature of the other of the core type and the cavity type is 50 ° C. or higher, and the average surface temperature of the one type is 5% lower than the average surface temperature of the other type.

Higher than ° C.

Preferably, there are a plurality of coating material inlets.

Preferably, the cyclic olefin is a norbornene-based monomer.

According to the present invention, there is provided a molded article having a film obtained by any of the in-mold coating methods described above.

Invention [0008] According to the in-mold coating method of the present invention, not only the front surface of the molded product near the coating material inlet, but also the side surface of the molded product in which the coating material is hard to flow far from the coating material injection port. The part also has a uniform film thickness, and a film can be formed with good reproducibility, and it is easy to remove the molded product.

Brief Description of Drawings

FIG. 1 is an overall schematic view showing an example of a mold apparatus capable of realizing the method of the present invention,

FIG. 2 is a perspective view showing one embodiment of a core mold of the mold apparatus of FIG. 1,

[FIG. 3] FIG. 3 is a schematic view of a state in which a molded product is fixed to a mold,

FIG. 4A is a partial perspective view for explaining an example of a molded article fixing means,

FIG. 4B is a partial perspective view for explaining an example of a molded article fixing means,

FIG. 5A is a partial perspective view for explaining another example of the molded article fixing means,

FIG. 5B is a partial perspective view for explaining another example of the molded article fixing means,

FIG. 5C is a partial perspective view for explaining another example of the molded article fixing means,

[FIG. 6A] FIG. 6A is a schematic diagram of a case using a mold having molded article fixing means (Example). [FIG. 6B] FIG. 6B is a case of using a mold having molded article fixing means (Example). [FIG. 7A] FIG. 7A is a schematic diagram of a case using a mold having no molded product fixing means (comparative example), [FIG. 7B] FIG. 7B is a mold having no molded product fixing means FIG. 4 is a schematic diagram of a case in which is used (Comparative Example).

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] The in-mold coating method of the present invention comprises a reaction injection molding step of reacting a molding material comprising a cyclic olefin, a catalyst component, and a catalyst active component in a mold to obtain a molded product; A coating forming step of injecting a covering agent into the mold and curing the molded product in a state where the coating material is fixed in the mold by means for fixing the molded product, and forming a coating on the surface of the molded product.

In the present invention, the molded article fixing means is not particularly limited as long as the molded article obtained by reaction injection molding in the mold can be fixed in the mold. It is particularly preferable that it is a concave portion, a convex portion provided on a mold, or a concave portion provided on a mold, which is preferably a molded article suction means. [0012] The recess provided in the mold is provided so as to be depressed from the mold surface of the mold, and the area above the recess (the area on the side where the recess is open) is not smaller than the bottom area of the recess. It is particularly preferable that the area of the concave portion is equal to the area of the concave portion so that the molded article can be firmly fixed. If the area above the concave portion is smaller than the bottom area of the concave portion, if the bending modulus of the molded product is 1.3 GPa or more, the molded product may not be able to take out the mold force after the completion of the film forming step.

Specific examples of the concave portion provided in the mold include a hollow such as a column, a trapezoid, a quadrangular column, and a triangular column, or a groove such as a horizontal column, a trapezoid, a quadrangular column, and a triangular column. Force to be applied Force in view of easiness of processing A column-shaped depression in which a depression is preferable is particularly preferable. In addition, the concave portion provided in the mold can be used together with the convex portion provided in the following mold.

Note that the recess provided in the mold may have a slide mechanism. The recess having the slide mechanism is provided so as to be movable in the mold. The concave portion having the slide mechanism is depressed from the mold surface in the reaction injection molding process-the film forming process, and is slid in the process of taking out the molded product after the film is formed so as to be substantially flush with the mold surface. (Or lower). By doing so, the molded product is separated from the mold surface, so that the molded product can be easily taken out.

[0013] The protrusion provided on the mold is provided so as to protrude from the mold surface of the mold, and the area above the protrusion is provided.

(It is preferable that the area on the tip side of the convex portion is not larger than the bottom area of the convex portion (meaning the area on the mold side of the convex portion). Is particularly preferable since the molded article can be fixed firmly. If the area of the convex part on the molded body side is larger than the bottom area of the convex part on the mold side, if the bending modulus of the molded product becomes 1.3 GPa or more, the molded product will not be able to take out the mold force after the completion of the film forming process. There is a certain force.

Specific examples of the protrusions provided on the mold include protrusions such as columnar, trapezoidal, quadrangular, and triangular prisms, and bank-like cylinders, trapezoids, quadrangular prisms, and triangular prisms. Although a protrusion may be mentioned, a columnar protrusion, which is preferably a protrusion, is particularly preferable from the viewpoint of ease of processing.

[0014] Further, the projection provided on the mold has a slide mechanism. A viewpoint of easiness is also preferable. The projection having the slide mechanism is provided so as to be able to enter and exit the mold. The convex portion having the slide mechanism is made to protrude the die surface force of the mold in the reaction injection molding process-the film forming process, and is slid in the process of taking out the molded product after the film is formed so as to be substantially flush with the mold surface ( (Or less). This facilitates removal of the molded product.

[0015] The total number of concave portions and convex portions provided in the mold is preferably 2 or more, more preferably 5 or more, and particularly preferably 8 or more, in order to fix the molded article to the mold with good balance.

[0016] The depth of the concave portion and the height of the convex portion provided in the mold are generally 1 to 50 mm, preferably 5 to 12 mm. If the depth of the concave portion and the height of the convex portion are too large, it may be difficult to remove the molded product.If the depth of the concave portion and the height of the convex portion are too small, the molded product may not be fixed properly. .

When the concave portion provided in the mold is a depression, the diameter of the inscribed circle is usually 1 to 50 mm, preferably 5 to 20 mm. When the protrusion provided on the mold is a projection, the diameter of the circumscribed circle is usually 2-52 mm, preferably 7-22 mm.

Further, when the concave portion provided in the mold is a groove, the width is usually 1 to 50 mm, preferably 5 to 20 mm, and the length is usually 0.1 to 2 m, preferably 0.5. — Lm. When the convex portion provided on the mold is in the shape of a bank, the width is 1 to 50 mm, preferably 5 to 20 mm, and the length is usually 0.1 to 2 m, preferably 0.5 to 20 mm. lm.

In the present invention, the molded article suction means is not particularly limited as long as the molded article is fixed to the mold by reducing the pressure between the mold and the molded article. A structure in which a decompression line is connected to the recess is preferable. The shape of the recess is the same as that of the recess provided in the mold. The recess having the slide mechanism here is arranged at a position substantially flush with the mold surface in the reaction injection molding process, and is slid so as to be retracted into the mold in the film forming process, and is formed on the mold surface. A recess is formed and the molded product is sucked and fixed by connecting the decompression line, and in the removal process of the molded product after forming the film, the decompression line is slid so as to push up to a position almost flush with the mold surface. Operate to cut. This facilitates removal of the molded product.

In the present invention, when the molded article fixing means is a concave or convex part provided in a mold, In the case, it is preferable to provide a molded product fixing means on a mold surface substantially parallel to the coating agent injection direction.

It is more preferable to provide the molded article fixing means on at least two of the mold surfaces substantially parallel to the coating agent injection direction. Two or more surfaces provided with the molded article fixing means are opposed to each other. It is particularly preferred to have a surface. When the molded product fixing means is a concave or convex portion provided in the mold and the molded product fixing means is provided on the mold surface substantially perpendicular to the coating material injection direction, the covering agent injection loca is also covered with high pressure. When the agent is discharged, the molded product fixing means may be dislodged depending on the conditions.If the molded product is fixed on only one side, the rigidity and shape of the molded product may vary. Also, there is a possibility that the corner of the molded product on the side not fixed may be inclined. The direction of the concave portions or convex portions provided in the mold is preferably substantially perpendicular to the direction in which the coating agent is injected, because the molded product can be firmly fixed.

[0020] In the present invention, when the molded product fixing means is a molded product suction means provided on a mold, it is preferable to provide the molded product fixing means on a die surface substantially perpendicular to a coating agent injection direction. . When the molded product fixing means is a molded product suction means provided on the mold and the molded product fixing means is provided on the mold surface substantially parallel to the coating material injection direction, high-pressure coating is performed from the coating material injection port. When the agent is ejected, the molded product is easily detached depending on the conditions. The direction of the molded article suction means provided on the mold is preferably substantially parallel to the coating material injection direction, because the molded article can be firmly fixed.

In the present invention, a mold composed of a core mold and a cavity mold is used, and one of the core mold and the cavity mold (hereinafter abbreviated as “mold Y”) is used. When coating the surface of the molded article on the side in contact with the coating agent, the molded article fixing means is installed on one of the core mold and the cavity mold (hereinafter abbreviated as “mold X”). In this case, the coating formed by the method of the present invention is formed on the entire surface of the molded article. On the other hand, the coating does not necessarily need to be formed on the entire surface of the molded article. Depending on the use of the molded article, it may be sufficient if the coating is formed on a part of the surface of the molded article. Therefore, even when the surface of the molded product in contact with the mold Υ is coated with the coating agent, the molded product fixing means may be provided on the mold Υ. Further, immediately before the coating agent is injected into the mold, the mold Y is slightly opened relative to the mold X with the molded product fixed to the mold X, and the mold Y is opened. It is also preferable that a gap is formed between the inner surface and the molded article to a degree that a flow path for the coating agent can be secured, and the coating agent is injected into the gap. In this case, usually, the mold is opened and the coating agent is injected after the mold is closed again. By relatively opening mold Y while fixing the molded product to mold X, mold Y and the molded product are separated, so even if mold Y is closed again, the flow path of the coating agent is easy. Can be secured. In particular, when the X-type is concave and the Y-type is convex, the molded article tends to adhere to the Y-type, which tends to secure the flow path of the covering agent, and thus this method is preferable.

In addition, while the mold X and the mold Y are closed, the coating agent may be injected between the inner surface of the mold Y and the molded product at a pressure higher than the mold clamping pressure (normally, about 10 MPa). .

[0022] The molded article fixing means in the present invention may be an undercoat layer formed by in-mold coating. In other words, even when the mold does not have a molded product fixing means, when the undercoat is injected into the mold and cured by in-mold coating, the molded product is fixed in the mold by the formed undercoat layer. Is done. Then, a good and uniform coating can be formed by coating the surface of the molded article with a covering agent. The primer and the coating may be of the same or different types.

The inlet for the undercoating agent and the inlet for the coating agent may be the same or may be provided separately. However, it is preferable to provide them separately. Even if the undercoating agent and the coating agent are of the same type, the undercoating agent injection port and the coating agent injection port are provided at positions where they complement each other, that is, the coating agent injection is provided in the vicinity of the area where the undercoating layer is difficult to form. By providing the inlet, a good and uniform coating can be formed.

Next, the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to this embodiment.

As shown in FIG. 1, a mold device 50 as one embodiment capable of realizing the method of the present invention includes a core mold (corresponding to mold X) 1 that can be divided in a mold opening direction D1 with respect to a division surface 51. , A cavity type (corresponding to the mold Y) 2. Then, the mold 52 is clamped between the core mold 1 and the cavity mold 2 at the dividing surface 51 so that the cavity 52 is formed inside.

In the present embodiment, the cavity mold 2 has a coating material injection port 3 formed therein. The core mold 1 is provided with mold surfaces 4 and 5 that are substantially parallel to a direction D2 (D2 = D1 in the present embodiment) in which the coating material is injected from the coating material injection port 3 into the cavity 52. As shown in FIG. 2, in the present embodiment, a concave portion 7 as an example of a molded article fixing means and the inside of the concave portion A convex portion 8 having a slide mechanism, which is movable toward, is provided. As shown in FIG. 4A, the projection 8 having the slide mechanism protrudes from the mold surfaces 4 and 5 in the reaction injection molding step and the coating forming step, but the molded article after the coating forming step with the coating agent is completed. In the unloading process, as shown in Fig. 4B, it is retracted to a position substantially flush (or less) with the mold surfaces 4 and 5 and actuated so that the molded product to be removed from the mold is not pressed. Let it. This facilitates removal of the molded product.

As shown in FIG. 3, the molded product fixing means provided on the mold surfaces 4 and 5 of the core mold 1 may be only the concave portions 7. In this case, the protrusion 12 of the molded article 11 formed corresponding to the concave section 7 is fixed by the concave section 7, and as a result, the molded article 11 is fixed.

As shown in FIGS. 5A, 5B and 5C, the molded product fixing means provided on the mold surfaces 4 and 5 of the core mold 1 is connected to a concave portion 15 having a slide mechanism as an example of the molded product suction means. May be the pressure reducing line 17. As shown in FIG. 5A, the concave portion 15 having the slide mechanism is located at a position substantially flush with the mold surfaces 4 and 5 in the reaction injection molding process and is not depressed. A recess is formed by drawing into the slide mechanism, and the molded article is sucked and fixed by connecting the decompression line 17. In the step of taking out the molded article after forming the film with the coating agent, as shown in FIG. 5C, the pressure reducing line 17 is cut by pushing up the slide mechanism so that the molded article is not sucked. This facilitates removal of the molded product.

Next, the operation and effect of the present invention will be described with reference to the schematic diagrams of FIGS. 6A and 6B.

In the case of the present invention having the molded article fixing means, as shown in FIGS. 6A and 6B, at the end of the reaction injection molding, the molded article 11 shrinks, so that a certain distance is provided between the core mold 1 and the cavity mold 2. The molded article 11 is firmly fixed with the empty space, and the positional relationship between the molded article 11 and the core mold 1 and the cavity mold 2 is changed even if the high-pressure coating material is discharged from the coating material inlet 3. And it is difficult to spread the coating agent. In addition to 22, the coating agent can be uniformly spread over the entire surface to be coated. On the other hand, in the case without the molded product fixing means, as shown in FIGS.7A and 7B, at the end of the reaction injection molding, the core mold la is weakened by the corner 22a of the la and the rib structure for reinforcing the molded product. A molded product 1 la exists in a state where a certain interval is left between the core type la and the cavity type 2 a in a supported state. Next, when the rigidity of the molded product 1 la is high or (hard), when the high-pressure coating material starts to be discharged from the coating material injection port 3a, the discharge pressure causes a slight gap in the mold to be formed. The molded product is tilted inside, and the coating agent does not sufficiently spread on the side surface 23a and the corner portion 22a of the molded product, resulting in poor film formation or uneven thickness of the film.

[0026] The average surface temperature of the mold X and the mold Y is usually 25 to 110 ° C. The lower limit of the surface average temperature of the mold X is preferably 50 ° C, more preferably 55 ° C, and further preferably 60 ° C. When the mold temperature is high, the reaction at the time of molding becomes intense, so that the maximum temperature of the resin increases. If the temperature difference between the resin and the mold becomes large, the molded product on the side in contact with the mold becomes so large that it shrinks in the horizontal direction, so that the molded product warps so as to bite into the mold. For this reason, it is preferable that the mold temperature is higher, because the molded article comes into close contact with the mold and the molded article can be easily fixed.

Also, if the temperature difference between the mold X and the mold Y is widened to some extent, the high temperature side force in the thickness direction of the uncured molded product will react toward the low temperature side, and the reaction will proceed. It is easy to develop on the lower side. For this reason, the temperature of the mold Y is preferably 5 ° C or more higher than the mold X from the viewpoint of not causing defects on the surface of the molded product on which the film is formed. Is more preferred 15 ° C or higher !, is even more preferred! / ,.

When the temperature difference between the two molds is reduced, the reaction proceeds equally in both cases, and there is a possibility that a defect remains inside the molded product and the defect is transferred to the surface on which the coating is formed.

The lower limit of the surface average temperature of the mold Y is preferably 70 ° C or higher. If the surface average temperature of the mold Y is too low, the coating may not be completely cured.

In the in-mold coating method of the present invention, usually, a cyclic olefin (solution A and ヽぅ) containing a metathesis polymerization catalyst component and a cyclic olefin (containing solution B) containing a catalytically active component are The mixture is mixed with a mixing head, the mixed solution is poured into a mold, and metathesis polymerization, crosslinking, and molding are performed at once in the mold. The mold used in the present invention is also a general one that has both the strength of the cavity mold and the core mold, except that it has a molded product fixing means. The mold clamping pressure is 0-20MPa. If a nitrogen gas is blown into the mold when the mixture is injected into the mold, a molded article having a good surface condition can be obtained, and the adhesiveness of the coating agent is improved.

[0028] The material of the mold is steel, forged or forged aluminum, iron or zinc alloy or the like, or sprayed, nickel or copper or the like, nickel, copper, chrome or the like, and resin. And the like. The structure of the mold should be determined in consideration of the pressure at which the mixture and the coating agent are injected into the mold.

[0029] The molding time varies depending on the cyclic olefin, the catalyst component, the catalytically active component, the composition ratio thereof, the mold temperature and the temperature difference, and is not uniform. Minutes, preferably 10 seconds to 5 minutes. If the length is shorter than this range, the crosslinking has not progressed sufficiently.If the molded product is soft and long, on the other hand, the crosslinking has progressed sufficiently, but the molding time is too long, the productivity is inferior, and the molding shrinks. The gap between the mold Y and the molded product becomes too large due to the increase in the thickness, and the coating becomes thicker and more easily cracked.

[0030] At a stage where the cross-linking of the molded article has sufficiently proceeded, that is, at a stage where the surface of the molded article can withstand the injection pressure and the flowing pressure of the coating agent, the injection of the coating agent does not drive the molded article. In this state, the coating agent is injected into the mold from the coating agent injection port using an injector while being fixed by the molded article fixing means. The injection pressure is from 1 to 50 MPa, more preferably from 3 to 30 MPa, particularly preferably from 5 to 22 MPa. If the injection pressure is too low, the coating material will not sufficiently penetrate and flow between the mold surface and the molded product surface, and if the injection pressure is too high, the coating material will sufficiently penetrate and flow, but the coating material will not. Injection equipment costs will be excessive, and the mold structure will need to be strengthened to withstand high pressures, resulting in poor economics.

The mounting position of the coating material inlet is preferably determined as appropriate in consideration of the mold structure and the flow of the coating material. The number of coating material inlets may be one if the coating material is distributed all over, but since the flow rate of the coating material is roughly inversely proportional to the distance from the coating material injection port, the number of coating material inlets is more effective. It is preferred to provide multiple inlets U ヽ. When a plurality of coating material inlets are installed, the number is usually 2-4, preferably 2-3. The distance between two adjacent coating agent inlets is usually 0.5 to 3 m, preferably 0.8 to 2 m. The If there are multiple injection ports, bubbles may be generated on the mating surface of the coating material injected from both injection ports. Therefore, adjust appropriately with the injection pressure of the coating material.

[0031] After the coating agent is injected, it is cured by maintaining the same at a predetermined temperature for a predetermined time. The curing time of the coating is 20 seconds and 16 minutes, preferably 60 seconds and 14 minutes. If it is shorter than this range, the curing of the covering agent is insufficient and the coating is not sufficient. On the other hand, if it is long, curing will be sufficient, but productivity will be poor.

The cyclic olefin used in the present invention has a metathesis-polymerizable cycloalkene group in a molecule thereof in a molecule, and a compound having at least one norbornene skeleton in the molecule (hereinafter referred to as “norbornene monomer”). Is abbreviated). Specific examples of cyclic olefins include dicyclopentadiene, tricyclopentadiene, cyclopentadiene-methylcyclopentadiene codimer, 5-ethylidene norbornene, norbornene, norbornane, and 5-cyclohexene. Renorbornene, 1,4,5,8-Dimethano-1,4,4a, 5,6,7,8,8a-Kitahydronaphthalene, 1,4-Methanol 1,4,4a, 5,6,7 , 8,8a—Citahydronaphthalene, 6-ethylidene—1,4,5,8—Dimethano—1,4,4a, 5,6,7,8,8a—Octahydronaphthalene, 6—ethylidene—1,4— Methano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 1,4,5,8-dimethano-1,4,4a, 5,6,7,8,8a-hexahydro Examples include naphthalene and ethylenebis (5-norbornene).

A mixture of two or more of these can be used, and a dicyclopentadiene or dicyclopentadiene can be mixed with a cyclic olefin having a polar group containing a different element such as oxygen or nitrogen. Mixtures containing at least 70 mol%, preferably at least 70 mol%, are particularly preferred.

[0033] The metathesis polymerization catalyst component used in the present invention is a metal salt or a metal complex such as tungsten, rhenium, tantalum, molybdenum, or ruthenium, and a metal salt or a metal complex of tungsten, molybdenum, or ruthenium is preferable. As the salt, halide and the like are preferable. More specifically, preferred are tungsten hexahalide, tungsten oxynolide, molybdenum pentahalide, and ruthenium phosphine complex. Organic ammonium tungstates, organic ammonium molybdates and the like can also be used.

[0034] In the case of a compound such as a metal salt of tungsten, upon contact with cyclic olefin, To start the polymerization, the tungsten compound is used by suspending it in an inert solvent such as benzene, toluene, or benzene, and adding a small amount of alcohol and z or phenols to solubilize it. . Unnecessary polymerization can be prevented by adding about 115 mol of a Lewis base or a chelating agent to 1 mol of the tungsten compound. Examples of such additives include acetylacetone, alkyl acetoacetate, tetrahydrofuran, and benzonitrile. When a polar group-containing monomer is used as the copolymerizable monomer, the monomer itself may be a Lewis base, and may also serve as an additive. In the present invention, the polymerization catalyst component is dissolved in the cyclic olefin to form a solution A and mixed with the solution B.

[0035] The catalytically active component used in the present invention is an organic metal compound of a metal belonging to Group I or Group III of the periodic table. Specific examples include teraalkyltin, alkylaluminum compounds, and alkylaluminum halides. Preferably, getyl aluminum chloride, diethyl aluminum chloride, trioctyl aluminum, dioctyl aluminum iodide, tetrabutyl tin and the like are exemplified. These catalytically active components are dissolved in the cyclic resin to form a solution B and mixed with the solution A.

[0036] If solution A and solution B are mixed and injected into a mold, polymerization is started. In order to prevent polymerization from starting during injection into the mold, it is preferable to add an activity regulator. . As such a regulator, a Lewis base is preferable, and an ethereal compound, an ester compound, a nitrile compound and the like are used. Specific examples include ethyl benzoate, butyl ether, and diglyme. When a polar group-containing monomer is used as a copolymerizable monomer, it may itself be a Lewis base, and may also function as a regulator. The regulator is preferably added to the solution B containing the catalytically active component.

[0037] When a tungsten conjugate is used as the polymerization catalyst component, it is 1/1000 to 1 / 1,000, preferably 1/1500 to 1 mol per 1 mol of the cyclic olefin. One mole per 2,500 minutes. When an aluminum compound is used as the catalytically active component, the molar ratio is 1/100 to 1 / 10,000, preferably 1/200 to 1 / 1,000 with respect to 1 mol of cyclic olefin. .

[0038] In the present invention, in order to improve or maintain the properties of the molded article, various properties of the molded article, and Various additives may be used as long as the adhesion and adhesion between the cured coating material and the molded article are not impaired. Examples of powerful additives include elastomers, fillers, reinforcing agents, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents, flame retardants, foaming agents, and softeners. , Tackifiers, plasticizers, release agents, deodorants, fragrances, pigments, extenders, and the like. These can be used alone or in combination.

[0039] Elastomer as an additive is effective for adjusting the viscosity of a solution and improving the impact resistance of a molded article. Styrene butadiene styrene triblock rubber, styrene isoprene styrene triblock rubber, polybutadiene, polyisoprene, butinole rubber, ethylene propylene rubber, nitrile rubber and the like are exemplified.

[0040] The additive is used by adding to solution A and Z or solution B, or is prepared as a third solution other than solution A and Z or solution B, and is added to solution A and solution B during reaction injection molding. It is added by a method of mixing together, or a method of previously filling in a mold. For example, a method in which a reinforcing material such as glass fiber is placed in a mold in advance and a solution is injected therein is suitable.

[0041] Examples of the coating agent and the undercoating agent used in the present invention include various types of node coating agents such as paints, fluorine resin-based lacquers, silicone resin-based lacquers, and silane-based hard coating agents. A paint is preferably used. The paint comprises (a) a vehicle component comprising an unsaturated polyester resin, an epoxy acrylate copolymer, a polyester acrylate polymer or a urethane acrylate polymer, (b) an ethylenically unsaturated monomer copolymerizable therewith, and (c) Contains a polymerization initiator.

[0042] Each of the unsaturated polyester resin, epoxy acrylate copolymer, polyester acrylate copolymer and urethane acrylate copolymer has an unsaturated double bond in the molecule, and has an unsaturated monomer component and a vehicle component. In addition, polymerization (curing reaction) is initiated by active radicals generated by thermal decomposition of an organic peroxide as a polymerization initiator. The active radical reacts with the unsaturated bond remaining in the reaction injection molded product of the cyclic olefin, and as a result, the molded product and the paint are chemically bonded, thereby exhibiting strong adhesion of the paint. Inferred. Two-component paints such as polyol resins that do not have unsaturated double bonds in the molecule and polyisocyanate hardeners use cyclic injection with reaction injection molded products. Is insufficiently adhered.

[0043] The unsaturated polyester resin is produced by a condensation reaction between an unsaturated dibasic acid such as maleic acid and fumaric acid and a polyhydric allyl such as ethylene glycol, propylene glycol, and trimethylolpropane. is there.

[0044] The epoxy acrylate copolymer is obtained by mixing an epoxy compound with an unsaturated carboxylic acid such as acrylic acid or methacrylic acid at a ratio such that the carboxyl group equivalent is 0.5 to 1.5 equivalent per 1 equivalent of epoxy group. It is produced by a ring-opening addition reaction.

[0045] The polyester acrylate copolymer is, for example, one produced by reacting a hydroxyl-terminated polyester polyol with an unsaturated carboxylic acid.

The urethane acrylate copolymer is produced by a method in which diisocyanate, a diol and a hydroxyl group-containing (meth) acrylate are mixed together and reacted, or by other known methods. As the hydroxyl group-containing (meth) acrylate, for example, the general formula CH

2 CRCO — (C H) —OH {where R is H or CH and n is an integer of 28

2 n 2n 3

It is preferably a compound represented by}.

[0047] Examples of the diisocyanate include toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyldiisocyanate, 1,2-diisocyanatoethane, hexamethylene diisocyanate, and 1,3bis (isocyanate Methyl) cyclohexane and the like. These can be used alone or in combination.

[0048] Examples of the diol include alkylene alcohols such as ethylene glycol, propylene alcohol, diethylene glycol, polyethylene glycol, and polypropylene alcohol, and diester diols which are diester reaction products of dicarboxylic acids or anhydrides thereof.

[0049] Particularly preferred paints are paints containing an epoxy acrylate copolymer or a urethane acrylate copolymer as a main component.

[0050] Examples of the ethylenically unsaturated monomer which is a vehicle component of the coating material include styrene, α-methylstyrene, chlorostyrene, butyltoluene, dibutylbenzene, methyl (meth) atalylate, and 1,6-xanediol diatalylate. , Tripropylene glycol diatalylate, trimethylolpropane tri (meth) acrylate, silicon acrylate, silicon diacrylate And the like. The amount of the ethylenically unsaturated monomer is from 20 to 200 parts by weight, preferably from 40 to 160 parts by weight, per 100 parts by weight of the unsaturated polyester resin or oligomer. Within this range, a paint having appropriate curing characteristics and viscosity can be obtained.

[0051] The viscosity of the coating agent is preferably 500 to 100 mPa's when measured at 30 ° C, and 600 to 7000 mPa's, from the viewpoint of preventing the coating agent from flowing around and generating bubbles. Force is more preferable, and 700-6000 mPa's force S is particularly preferable. The above viscosity is a value measured at a rotational speed of 30 rpm using a No. 2 rotor using a B-type viscometer.

[0052] The polymerization initiator for polymerizing the vehicle component is preferably an organic peroxide. Examples thereof include bis (4t-butylcyclohexyl) peroxydicarbonate, lauroyl peroxide, t-amylperoxy-2-ethylhexanoate, benzoyl peroxide, and t-butylperoxy-2-ethylhexanoate. The amount of the organic peroxide is 0.1 to 15 parts by weight based on 100 parts by weight of the vehicle component. The strong organic peroxide is generally added as a stable solvent and paste. A preferable solvent is one that is stable to organic peroxides, for example, phthalic acid esters.

[0053] In addition to the above-mentioned components, the coating agent may be, if necessary, a metal powder, a release agent, a curing accelerator, a polymerization inhibitor, an ultraviolet absorber, a light stabilizer, a coloring pigment, an extender pigment, and a conductive pigment. , Modified resin, surface conditioner and the like.

[0054] These coating agents can sufficiently adhere to the surface of a molded article without using a primer. This is presumed to be due to the fact that active radicals generated by the thermal decomposition of the coating component react with the unsaturated bond remaining in the reaction injection molded article of the cyclic olefin in a trace amount. Example

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

[Examples 1-1, 6]

(Mold and coating agent injection device)

An aluminum mold for bumper molding of automobiles, consisting of a core mold (corresponding to mold X) and a cavity mold (corresponding to mold Y). The cavity mold has one coating material injection port, An injector with a maximum injection pressure of 40 MPa was attached to the inlet. As the means for fixing the molded article, the same one as shown in Fig. 2 is used, and three opposing sides of the core mold are provided with three recesses each having a diameter of 10 mm and a depth of 7 mm, a diameter of 15 mm, and a height of 15 mm. Three convex portions having a slide mechanism of 10 mm in length were provided alternately and at equal intervals, and three concave portions having a diameter of 7 mm and a depth of 10 mm were provided on each of two other opposing side surfaces of the core type. The dimensions of the bumper were 1900 mm in length and 200 mm in width.

(Metathesis Polymerizable Cyclic Olefins)

Solution A1: A solution containing dicyclopentadiene as a main component containing a polymerization catalyst component (Pentam 2000 A solution: manufactured by RIMTEC Corporation).

Solution A2: solution containing dicyclopentadiene as a main component containing a polymerization catalyst component (Meton T 02A solution: manufactured by RIMTEC Corporation)

Solution B1: A solution containing dicyclopentadiene containing a catalytically active component as a main component (Pentam 2000B solution: manufactured by RIMTEC Corporation).

Solution B2: a solution containing dicyclopentadiene containing a catalytically active component as a main component (Meton T 02B solution: manufactured by RIMTEC Corporation).

(Coating agent)

100 parts by weight of a paint containing a urethane acrylate copolymer as a main component (Plugras # 5000: manufactured by Dainippon Co., Ltd.) 1 part by weight of dibutyl phthalate and Parikidox 16 (manufactured by I-Daiyaku Axo Co., Ltd.) Paint A was obtained using 1 part by weight of paste and diluent for Pluglas # 5000.

The viscosity of the obtained coating material A at 30 ° C was measured using a B-type viscometer at a rotation speed of 30 rpm using a second rotor, and was found to be 900 mPa's.

(Forming and Formation of Film)

The cavity mold and the core mold are heated to the temperature shown in Table 1, the molded article is clamped with a pressure of 0.49 MPa, and the same amount of solution is mixed in a mixing head using a RIM molding machine in the mold. A1 (or A2) and solution B1 (or B2) were impinged and mixed, and the resulting mixture was poured into a mold. After filling the mixture, the mold was kept at the mold temperature. The molded product produced by reaction injection molding is fixed by molded product fixing means (concave and convex portions) provided on the core mold. In this state, coating A was injected into the mold at 20 MPa as a coating agent. After the coating was injected, the mold was kept at the mold temperature for 3 minutes. Then, the mold was opened and the bumper on which the coating was formed was taken out.

Table 1 shows the results of visually observing the appearance of the design surface of the bumper on which the coating was formed, and the measured values of the film thickness. The thickness of the design surface was divided into five in the longitudinal direction and three in the short direction by a method of directly measuring the cross section of the molded body, and a total of 15 points were measured at the center of each section. The appearance of the design surface was determined according to the following criteria.

〇: The coating state is good.

Δ: There is a part where the color of the molded article main body is transparent and the coating is thin.

X: There is a portion where a film is not formed.

[Comparative Example 1]

Example 1 except that the mold was not provided with a molded product fixing means and that the paint A was injected into the mold in a state where the molded product in the mold was not fixed, and the temperatures of the cavity mold and the core mold were set to the values shown in Table 1. The experiment was performed in the same manner as in 1. The results are shown in Table 1.

[Comparative Example 2]

Example 1 except that the mold was not provided with a molded product fixing means and that the paint A was injected into the mold in a state where the molded product in the mold was not fixed, and the temperatures of the cavity mold and the core mold were set to the values shown in Table 1. The experiment was performed in the same manner as in 3. The results are shown in Table 1.

[Example 5]

The molding was performed in the same manner as in Comparative Example 1 except that the cavity mold had two coating agent injection ports and the temperature of the cavity mold and the core mold were as shown in Table 1. In addition, one coating agent injection port was provided at the same position as in Comparative Example 1 to serve as an undercoating agent injection port, and the other was provided at a position substantially point-symmetric with respect to the surface center of gravity of the molded product. And

Next, paint A was injected into the mold as a primer from one of the coating agent inlets, and after the coating agent was injected, the mold was kept at the mold temperature for 3 minutes to form an undercoat layer. Subsequently, the other coating agent injection loca also injected paint A as a coating agent into the mold at 20 MPa. After pouring the coating, the mold was kept at the mold temperature for 3 minutes. Then, the mold was opened and the bumper on which the coating was formed was taken out. Table 1 shows the results. In addition, the film thickness here includes the undercoat layer. The total thickness of the coating.

[table 1]

Molded product solid solution Solution cavity type core type temperature

Design surface appearance evaluation

(A) (B) Temperature C ° c) (° C) Average (Jtim)

Front side corner

Example 1 I A1 B1 87 74 〇〇〇 40 30 Example 2 I A1 B1 87 71 〇〇〇 140 30 Example 3 I A2 B2 87 73 〇 o 〇 140 30 Example 4 I A2 B2 87 66 〇〇〇 140 30 Example 5 II A1 B1 90 50 〇〇〇 250 30 Example 6 I A2 B2 87 74 〇 o 〇 140 25 Comparative Example 1 None A1 B1 88 78 〇 X 160 50 Comparative Example 2 None A2 B2 90 60 Ο Ο X 160 50 Mold fixing means 1: Concave and convex parts provided on mold

Mold fixing means 品: Undercoat layer

i! n [0065] From Table 1, it can be seen that in Example 1-16 in which the coating material was injected into the mold while the molded product was fixed by the molded product fixing means, not only the front of the molded product near the coating material injection port but also the front surface of the molded product Also, coating was performed well on the side and corners of the molded product, which was difficult to wrap around the coating agent far from the coating agent inlet, and the thickness variation of the entire design surface was small. On the other hand, in the case of Comparative Example 1-2, in which the mold was not provided with the molded article fixing means and the coating material was injected into the mold in a state where the molded article in the mold was not fixed, in the case of Comparative Example 1-2, the molded article close to the coating material injection port was used. Although the coating condition on the front of the molded product was good, uncoated portions occurred on the side surfaces and corners of the molded product where the coating material was difficult to flow far from the coating material injection port. In addition, the thickness of the entire design surface varied greatly.

[Example 7]

Molding was performed in the same manner as in Example 4 except that the mold was opened 2 cm 15 seconds before injecting the coating agent, and then closed again, using a mold in the shape of a washing floor with a concave X shape and a convex Y shape. Was done. The appearance of the resulting design surface was good on all surfaces, sides and corners, with an average film thickness of 140 m and a standard deviation of 30 m. The size of the washing floor was about 650 mm square.

Claims

The scope of the claims

[1] a reaction injection molding step of reacting a molding material comprising a cyclic olefin, a catalyst component, and a catalyst active component in a mold to obtain a molded product;

A film forming step of injecting a covering agent into the mold and curing the molded product in a state where the molded product is fixed in the mold by molded product fixing means, and forming a film on the surface of the molded product; In-mold coating method having.

2. The in-mold coating method according to claim 1, wherein the molded product fixing means is a concave portion or a convex portion provided in a mold.

3. The in-mold coating method according to claim 2, wherein the concave portion or the convex portion provided in the mold has a slide mechanism.

4. The in-mold coating method according to claim 1, wherein the molded product fixing means is a molded product suction means provided on a mold.

[5] In a case where a mold formed by a core mold and a cavity mold is used, and the surface of a molded article in contact with one of the core mold and the cavity mold is coated with a coating agent, 2. The in-mold coating method according to claim 1, wherein the molded article fixing means is provided on one of the mold and the mold of the cavity.

[6] One of the core mold and the cavity mold is slightly opened relative to the other mold, and a coating agent is provided between the inner surface of the one mold and the molded article. 6. The in-mold coating method according to claim 5, wherein a gap is formed such that the flow path can be secured, and a coating agent is injected into the gap.

7. The in-mold coating method according to claim 1, wherein the molded article fixing means is an undercoat layer formed by in-mold coating.

[8] In the case where a mold formed by a core mold and a cavity mold is used, and the surface of a molded article in contact with one of the core mold and the cavity mold is coated with a coating agent, The average surface temperature of the other mold is at least 50 ° C, and the average surface temperature of the one mold is at least 5 ° C higher than the average temperature of the other mold. 2. The in-mold coating method according to claim 1, wherein:

[9] The in-mold coating method according to claim 1, wherein the coating agent has a plurality of injection ports.

10. The in-mold coating method according to claim 1, wherein the cyclic olefin is a norbornene-based monomer.

[11] A molded article having a film obtained by the in-mold coating method according to claim 1.