Mold for injection molding and method for injection molding of thermosetting composition

Abstract

To provide a technology that suppresses the generation of burr in injection molding of a thermosetting composition.SOLUTION: Provided is a curable composition that contains (A) a phosphate group-containing (meth)acrylate compound, (B) a trifunctional or higher polyfunctional (meth)acrylate compound, and one or more selected from (C) an urethane(meth)acrylate compound and (D) a polyester(meth)acrylate compound and in which the contained amount of (B) component is 30 to 70 pts.mass for the total 100 pts.mass of (meth)acryloyl group-containing components.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a curable composition, an injection molding mold, and a method for injection molding a thermosetting composition. [Background technology]

[0002] Light-emitting devices that use optical semiconductors such as light-emitting diodes (LEDs), which have become increasingly popular in recent years, are usually manufactured by molding a synthetic resin as a reflective material (reflector) onto a concave lead frame, fixing an optical semiconductor (LED) onto the resulting lead frame molding, and sealing it with a sealing material such as epoxy resin or silicone resin.

[0003] As a material for a reflector, Patent Document 1 discloses a composition in which a white pigment such as titanium oxide is blended with a thermosetting resin such as an acrylate resin. According to Patent Document 1, by using the composition, it is possible to obtain a cured product that has excellent heat resistance, weather resistance, and adhesion to surrounding members. Patent Document 2 describes the use of a thermosetting composition containing a (meth)acrylate compound and having a predetermined shear viscosity as a reflective material (reflector) for optical semiconductors, with the aim of suppressing the generation of burrs when forming a reflector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 056972 [Patent Document 2] JP 2016-8230 A Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, the material for the reflective material is filled into a mold by injection or the like, and then heated at a predetermined temperature and thermally cured to become the reflective material. The reflective material obtained in this way may develop burrs when thermally cured in the mold. If burrs develop in the reflective material, this may result in problems such as reduced work efficiency due to the need to remove the burrs, or poor appearance of the product. An object of the present invention is to provide a technique for suppressing the generation of flash during injection molding of a thermosetting composition.

[0006] The present inventors have found that burrs in a molded body are easily generated when a gap is generated between the molded body and the mold when the mold is pressed. They have also found that forming a resin film on the surface of the mold that faces the molded body is effective in suppressing burrs. As a result of intensive research based on the above findings, the present inventors discovered that a coating obtained by curing a specified curable composition is effective in suppressing burrs and has excellent durability, thereby completing the present invention. [Means for solving the problem]

[0007] According to the present invention, the following curable composition and the like are provided. 1. (A) a phosphate group-containing (meth)acrylate compound; (B) a trifunctional or higher polyfunctional (meth)acrylate compound; (C) one or more selected from a urethane (meth)acrylate compound and (D) a polyester (meth)acrylate compound; A curable composition, wherein the content of the component (B) is 30 to 70 parts by mass per 100 parts by mass in total of components containing a (meth)acryloyl group. 2. The curable composition according to 1, wherein the molecular weight of the (B) component is less than 800. 3. The curable composition according to 1 or 2, further comprising (E) a polymerization initiator. 4. The curable composition according to any one of 1 to 3, further comprising (F) a (meth)acrylate compound having a viscosity of 100 mPa s or less at 25°C as a (meth)acrylate compound other than the components (A) to (D). 5. A mold for injection molding, comprising a cured film of the curable composition according to any one of 1 to 4 on at least a part of the surface facing a molded body. 6. A method for injection molding a thermosetting composition using an injection mold according to 5. Effect of the Invention

[0008] According to the present invention, a technique for suppressing the generation of burrs during injection molding of a thermosetting composition can be provided. Specifically, a curable composition that can give a cured film that has excellent adhesion to a mold and can suppress the generation of burrs can be provided. In addition, a mold for injection molding that can suppress the generation of burrs in a molded body and a method for injection molding a thermosetting composition using the mold for injection molding can be provided. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an injection molding die according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Curable composition] A curable composition according to one embodiment of the present invention includes (A) a phosphoric acid group-containing (meth)acrylate compound, (B) a trifunctional or higher polyfunctional (meth)acrylate compound, and at least one selected from (C) a urethane (meth)acrylate compound and (D) a polyester (meth)acrylate compound, and is characterized in that the content of the (B) component is 30 to 70 parts by mass (%) relative to 100 parts by mass (%) in total of the components containing a (meth)acryloyl group.

[0011] In this specification, the term "component containing a (meth)acryloyl group" refers to a compound containing one or more (meth)acryloyl groups in its molecular structure, specifically, the above-mentioned components (A) to (D) and the below-mentioned component (F). In addition, the term "(meth)acryloyl group" refers to an acryloyl group or a methacryloyl group. Similarly, the term "(meth)acrylic acid" refers to an acrylic acid or a methacrylic acid, and the term "(meth)acrylate" refers to an acrylate or a methacrylate.

[0012] The curable composition of the present embodiment is used, for example, to form a cured film that covers the surface of a mold used for molding a resin. By injection molding the thermosetting composition using a mold on which a cured film has been formed, the generation of burrs can be suppressed. In addition, the adhesion between the mold and the cured film is good, and the cured film has high hardness, so it is difficult to be scratched. Hereinafter, each component of the curable composition of the present embodiment (hereinafter, sometimes simply referred to as the composition) will be described.

[0013] <Component (A)> The component (A) is a phosphate group-containing (meth)acrylate compound. In the curable composition of the present embodiment, the use of the component (A) can suppress peeling of the cured film from the mold surface and the associated generation of burrs in the molded product.

[0014] The component (A) may be a phosphate group-containing (meth)acrylate having at least one (meth)acryloyl group in one molecule. For example, 2-acryloyloxyethyl acid phosphate (e.g., "Light Acrylate P-1A(N)" manufactured by Kyoeisha Chemical Co., Ltd.), ethyl (meth)acrylate acid phosphate (e.g., "Light Ester P-1M" manufactured by Kyoeisha Chemical Co., Ltd.), bis[(2-(meth)acryloyloxy)ethyl]phosphate (e.g., "KAYAMER PM-2" manufactured by Nippon Kayaku Co., Ltd.), 2-(meth)acryloyloxyethyl caproate acid phosphate (e.g., "KAYAMER PM-21" manufactured by Nippon Kayaku Co., Ltd.), 2-hydroxyethyl (meth)acrylate acid phosphate (e.g., "JPA-514" manufactured by Johoku Chemical Industry Co., Ltd.), 10-(meth)acryloyloxydecamethylene acid phosphate (e.g., "MDP" manufactured by Kuraray Noritake Dental Co., Ltd.), and the like. The component (A) may be used alone or in combination of two or more types.

[0015] The content of the (A) component in the composition is, for example, 0.01 to 30 parts by mass, preferably 0.1 to 25 parts by mass, more preferably 0.2 to 20 parts by mass, and even more preferably 0.3 to 15 parts by mass, relative to 100 parts by mass of the total of the components containing a (meth)acryloyl group. When the content of the component (A) is within the above range, the adhesion between the obtained cured film and a mold tends to be sufficiently high. If the content of component (A) exceeds 30 parts by mass, there will be no problem with adhesion to the mold, but the molded article obtained by molding will have poor releasability from the mold, which may have an adverse effect on productivity.

[0016] <(B) component> The (B) component is a polyfunctional (meth)acrylate compound having three or more functionalities. The (B) component is contained in the composition of the present embodiment, which mainly increases the surface hardness of the obtained cured film, and can suppress the occurrence of scratches in the cured film. Therefore, by using a mold having the cured film, it is possible to suppress the occurrence of burrs in a molded product due to scratches in the cured film.

[0017] The component (B) is, for example, a compound having three or more (meth)acryloyl groups in one molecule. Specific examples thereof include trifunctional compounds such as trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane triacrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethoxylated glycerin tri(meth)acrylate, propoxylated glycerin tri(meth)acrylate, and pentaerythritol tri(meth)acrylate; tetrafunctional compounds such as pentoerythritol tetra(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate; and hexafunctional compounds such as dipentaerythritol hexa(meth)acrylate.

[0018] Among these, trifunctional compounds and tetrafunctional compounds are preferably used because they can easily provide a viscosity suitable for application to a mold in the composition. The component (B) may be used alone or in combination of two or more.

[0019] In this specification, a compound having three or more (meth)acryloyl groups and a phosphate group in one molecule is not included in the "tri- or more functional polyfunctional (meth)acrylate compound (B)" but is included in the above-mentioned "phosphate group-containing (meth)acrylate compound (A)."

[0020] The component (B) preferably has a molecular weight of less than 800, and more preferably from 200 to 700, from the viewpoint of obtaining a suitable surface hardness in the resulting cured film.

[0021] The content of the (B) component in the composition is 30 to 70 parts by mass per 100 parts by mass of the total of the components containing (meth)acryloyl groups. By setting the content within this range, the obtained cured film can have a moderately sufficient surface hardness and can suppress the occurrence of scratches. In addition, the adhesion to the mold is also improved. The content of the component (B) is more preferably from 35 to 65 parts by mass, and further preferably from 40 to 65 parts by mass.

[0022] <(C) component> The component (C) is a urethane (meth)acrylate compound. The inclusion of the component (C) mainly imparts an appropriate strength to the cured film obtained. Therefore, by using a mold having the cured film, the occurrence of scratches and burrs can be suppressed.

[0023] The component (C) can be obtained, for example, by esterifying a polyurethane oligomer obtained by reacting a polyether polyol or polyester polyol with a polyisocyanate, with (meth)acrylic acid.

[0024] Examples of component (C) commercially available products include the Art Resin series UN-333, UN-353, UN-350, UN-7600, UN-7700, UN-9000PEP, UN-9200A, UN-3320HC, UN-904 (all manufactured by Negami Chemical Industrial Co., Ltd.), U-2000PA, UA-290TM, and U-15HA (all manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0025] Among these, bifunctional urethane acrylates such as UN-7700 and UN-9000PEP are preferably used because they can provide a cured film with excellent strength. The component (C) may be used alone or in combination of two or more types.

[0026] In this specification, a urethane (meth)acrylate compound having three or more (meth)acryloyl groups in one molecule is not included in the above-mentioned "tri- or more functional polyfunctional (meth)acrylate compound (B)" but is included in the "urethane (meth)acrylate compound (C)".

[0027] In one embodiment, from the viewpoint of imparting strength to the resulting cured film, the weight average molecular weight of the (C) component is preferably 2,000 or more, and more preferably 2,000 to 30,000. In this specification, the weight average molecular weight is a value measured by GPC (Gel Permeation Chromatography).

[0028] The content of the component (C) in the composition is, for example, 1 to 30 parts by mass, preferably 3 to 30 parts by mass, and more preferably 5 to 30 parts by mass, relative to 100 parts by mass in total of the components containing a (meth)acryloyl group. It is more preferably 5 to 20 parts by mass.

[0029] <(D) component> The component (D) is a polyester (meth)acrylate compound (D). The inclusion of the component (D) mainly imparts an appropriate strength to the cured film obtained. Therefore, by using a mold having the cured film, the occurrence of scratches and burrs can be suppressed.

[0030] The (D) component can be obtained, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends, obtained by condensation of a polycarboxylic acid and a polyhydric alcohol, with (meth)acrylic acid, or by esterifying the hydroxyl groups at both ends of an oligomer obtained by adding an alkylene oxide to a polycarboxylic acid, with (meth)acrylic acid.

[0031] Examples of the component (D) include commercially available products such as CN2203, CN2270, CN2271, CN2272, CN2273, CN2274, and CN2283 (all manufactured by Arkema), EBECRYL810, EBECRYL853, EBECRYL884, and EBECRYL885 (all manufactured by Daicel-Allnex). Among these, bifunctional polyester acrylates such as CN2270 and CN2283 are preferably used because they can provide a cured film with excellent strength. The component (D) may be used alone or in combination of two or more types.

[0032] In this specification, a polyester (meth)acrylate compound having three or more (meth)acryloyl groups in one molecule is not included in the above-mentioned "tri- or higher functional (meth)acrylate compound (B)" but is included in the "polyester (meth)acrylate compound (D)".

[0033] The content of the (D) component in the composition is, for example, 1 to 30 parts by mass, preferably 3 to 30 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the total of the components containing (meth)acryloyl groups.

[0034] In this embodiment, it is sufficient to include one or more selected from the above-mentioned component (C) and component (D). From the viewpoint of obtaining a good strength in the obtained cured film, it is preferable to include both the component (C) and the component (D). The total content of the (C) component and the (D) component in the composition is, for example, 1 to 30 parts by mass, preferably 3 to 30 parts by mass, more preferably 5 to 30 parts by mass, and even more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the total of the components containing (meth)acryloyl groups. Furthermore, the blending ratio (mass ratio) of the components (C) and (D) is not particularly limited, but is preferably component (C):component (D)=20:80 to 80:20, and more preferably 30:70 to 70:30.

[0035] <(E) component> The composition of one embodiment may contain a polymerization initiator as component (E). Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator.

[0036] The thermal polymerization initiator is not particularly limited, but examples thereof include ketone peroxides, hydroperoxides, diacyl peroxides, dialkyl peroxides, peroxyketals, alkyl peresters (peroxy esters), and peroxycarbonates.

[0037] Specific examples of ketone peroxides include methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide. Specific examples of hydroperoxides include 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, p-menthane hydroperoxide, and diisopropylbenzene hydroperoxide. Specific examples of diacyl peroxides include diisobutyryl peroxide, bis-3,5,5-trimethylhexanol peroxide, dilauroyl peroxide, dibenzoyl peroxide, m-toluoylbenzoyl peroxide, and succinic acid peroxide. Specific examples of dialkyl peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,3-bis(t-butylperoxyisopropyl)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3. Specific examples of peroxyketals include 1,1-di-t-hexylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-hexylperoxycyclohexane, 1,1-di-t-butylperoxy-2-methylcyclohexane, 1,1-di-t-butylperoxycyclohexane, 1,1-di(t-amylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, and 4,4-bis-t-butylperoxypentanoate butyl. The above-mentioned thermal polymerization initiators may be used alone or in combination of two or more.

[0038] Specific examples of alkyl peresters (peroxy esters) include 1,1,3,3-tetramethylbutyl peroxy neodecanoate, α-cumyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxy neoheptanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy isobutyrate, di-t-butyl peroxy hexahydroterephthalate, 1,1,3,3-tetramethylbutyl peroxy 3,5,5-trimethylhexanate, t-amylperoxy 3,5,5-trimethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyacetate, t-butylperoxybenzoate, dibutylperoxytrimethyladipate, 2,5-dimethyl-2,5-di-2-ethylhexanoylperoxyhexane, t-hexylperoxy-2-ethylhexanoate, t-hexylperoxyisopropyl monocarbonate, t-butylperoxylaurate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5-di-benzoylperoxyhexane, and the like. Specific examples of peroxycarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxycarbonate, di-4-t-butylcyclohexyl peroxycarbonate, di-2-ethylhexyl peroxycarbonate, di-sec-butyl peroxycarbonate, di-3-methoxybutyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diisopropyl peroxydicarbonate, t-amyl peroxyisopropyl carbonate, t-butyl peroxyisopropyl carbonate, t-butyl peroxy-2-ethylhexyl carbonate, and 1,6-bis(t-butylperoxycarboxyloxy)hexane.

[0039] Examples of the photopolymerization initiator include benzyl ketal-based radical photopolymerization initiators, α-hydroxyacetophenone-based radical photopolymerization initiators, benzoin-based radical photopolymerization initiators, and aminoacetophenone-based photoinitiators. An example of the benzyl ketal-based photoradical polymerization initiator is 2,2-dimethoxy-2-phenylacetophenone. Examples of the α-hydroxyacetophenone-based photoradical polymerization initiator include 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl-phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-methylpropanone, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one. Examples of the benzoin-based photoradical polymerization initiator include benzoin, benzoin isobutyl ether, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. Examples of the aminoacetophenone-based photoradical polymerization initiator include 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, and the like. The above-mentioned photopolymerization initiators may be used alone or in combination of two or more.

[0040] From the viewpoint of polymerization reactivity, the content of the component (E) is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass in total of the components containing a (meth)acryloyl group.

[0041] <(F) Component> In one embodiment, the composition may contain, as component (F), a (meth)acrylate compound other than the above-mentioned components (A) to (D) within a range that does not impair the effects of the present invention. The component (F) is blended mainly as a diluent for adjusting the viscosity of the entire composition. By containing the component (F), for example, the viscosity of the composition can be adjusted to be suitable for use as a coating agent.

[0042] Examples of the (F) component include methyl (meth)acrylate, ethyl (meth)acrylate, lauryl (meth)acrylate, hydroxyethyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, glycidyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, one-terminal (meth)acrylic modified silicone oil, and both-terminal (meth)acrylic modified silicone oil. The component (F) may be used alone or in combination of two or more types.

[0043] In one embodiment, from the standpoint of obtaining a viscosity suitable for application to the surface of a mold, the viscosity of component (F) at 25° C. is preferably 100 mPa·s or less, and more preferably 1 to 50 mPa·s.

[0044] The content of the (F) component in the composition is 1 to 50 parts by mass, preferably 1 to 40 parts by mass, more preferably 3 to 30 parts by mass, and even more preferably 5 to 25 parts by mass, relative to 100 parts by mass of the total of the components containing a (meth)acryloyl group.

[0045] <Additives> In addition to the above components (A) to (F), the curable composition of the present embodiment may contain additives such as antioxidants, light stabilizers, ultraviolet absorbers, plasticizers, inorganic fillers, colorants, antistatic agents, lubricants, release agents, flame retardants, leveling agents, and defoamers. Known additives may be used.

[0046] In one embodiment, the components (A) to (F) make up 90% by mass or more, 95% by mass or more, 99% by mass or more, or substantially 100% by mass of the entire composition. In the case of "substantially 100% by mass", unavoidable impurities may be included.

[0047] The composition of the present embodiment can be prepared by mixing the above-mentioned (A) component, (B) component, at least one of (C) component and (D) component, and optional (E) component, (F) component and additives in a predetermined ratio. There is no particular limitation on the mixing method, and any known means such as a stirrer (mixer) can be used. In addition, mixing can be performed at room temperature, under cooling, or under heating, and under normal pressure, reduced pressure, or increased pressure.

[0048] The curable composition of the present embodiment can be used to form a cured film to be formed on a mold used for molding a resin. For example, the curable composition is a material suitable for forming a cured film that covers the surface of a mold used for injection molding. The cured film obtained from the curable composition of the present embodiment has excellent adhesion to a mold and excellent scratch resistance, and can suppress peeling of the film from the mold and scratches on the film surface. Therefore, by using a mold having the cured film to mold a molded body such as a thermosetting composition, it is possible to suppress the occurrence of a gap between the molded body and the mold when pressed by the mold, and to obtain a good molded body without burrs.

[0049] [Injection mold] An injection molding die according to one embodiment of the present invention has a cured film obtained by curing the curable composition of the present invention, on at least a part of the surface facing a molded body. FIG. 1 is a schematic cross-sectional view of an injection molding die according to one embodiment of the present invention. The injection molding die 10 has a fixed die 11 having a holding part 111 for holding the molded body, and a movable die 12 disposed opposite the fixed die 11. The movable die 12 has a pressing part 122 having an opposing surface 121 that faces the molded body. The opposing surface 121 of the movable die 12 is provided with a cured film 200 obtained by curing the curable composition of the present invention.

[0050] Next, a method for manufacturing the injection molding die of this embodiment will be described. First, a curable composition is applied to the opposing surface 121 of the movable mold 12 to form a coating film. The coating method is not particularly limited, and any known method can be used, such as spin coating, spray coating, flow coating, and dip coating.

[0051] Next, the coating film formed on the opposing surface 121 is cured by light or heat to form a cured film 200. The method for curing the coating film is not particularly limited, and for example, a curing method by irradiation with ultraviolet light or a heat curing method can be used. Both methods may be used in combination. In the UV curing method, the amount of UV light is usually 50 to 50,000 mJ / cm 2 Approximately, preferably 100 to 20,000 mJ / cm 2 After the ultraviolet irradiation, a post-heat treatment may be carried out, and it is preferable to carry out the post-heat treatment at, for example, 70 to 200° C. for 0.1 to 12 hours. In the heat curing method, the curing temperature is usually about 50 to 200° C., preferably 100 to 180° C. By setting the temperature at 50° C. or higher, it is possible to prevent curing failure, and by setting the temperature at 200° C. or lower, it is possible to prevent coloring, etc. The curing time differs depending on the components contained in the composition, but is usually preferably 0.1 to 6 hours.

[0052] [Method of Injection Molding Thermosetting Composition] In a method for injection molding a thermosetting composition according to one embodiment of the present invention, the thermosetting composition is molded using the above-described injection molding die of the present invention. The thermosetting composition used in the present embodiment is not particularly limited, and for example, those described in Patent Documents 1 and 2 can be used. The injection molding device and molding conditions are also not particularly limited, and for example, the device and conditions described in Patent Document 2 can be used.

[0053] For example, when an injection molding die 10 (hereinafter simply referred to as die 10) shown in FIG. 1 is used for injection molding, a filling section (not shown) is connected to the die 10, which fills the thermosetting composition, which is a raw material composition, into the die 10 by, for example, rotating a screw.

[0054] The thermosetting composition supplied to the filling section from a raw material tank (not shown) is sent forward while being stirred and mixed by the rotation of the screw, and is injected into the mold 10 at high speed and high pressure. The fixed mold 11 and the movable mold 12 of the mold 10 are heated to 30 to 250° C., preferably 50 to 200° C., and more preferably 80 to 180° C. by a heating device (not shown). When the thermosetting composition is injected into the mold 10 from the filling section, the holding section 111 of the fixed mold 11 holds the thermosetting composition (molded body) injected from the filling section. From this state, the movable mold 12 is brought close to the fixed mold 11, and the mold is clamped. With the cured film 200 of the movable mold 12 in contact with the thermosetting composition, the movable mold 12 is brought even closer to the fixed mold 11, whereby the thermosetting composition is pressed by the pressing section 122. The pressure applied to the thermosetting composition is not particularly limited, but is, for example, 0.1 to 30 MPa, and more preferably 1 to 20 MPa. Next, when the thermosetting composition is thermally cured to form a molded body, the movable mold 12 is separated from the fixed mold 11, and the molded body held by the holding portion 111 of the fixed mold 11 is removed.

[0055] The above-described method for injection molding a thermosetting composition according to the present embodiment uses the injection molding die of the present invention, and therefore the molded body can be pressed without generating a gap between the die and the molded body, thereby making it possible to obtain a molded body with reduced burrs. In addition, the cured film of the mold of the present invention has excellent adhesion to the mold and excellent scratch resistance, and the occurrence of film peeling and scratches on the film surface is suppressed. Therefore, by pressing a molded body using a mold having the cured film, damage to the molded body caused by scratches on the cured film and damage to the molded body caused by excessive pressing force from the mold can be suppressed, and a molded body with suppressed burrs can be obtained. In addition, the cured film of the mold of the present invention has excellent adhesion to the mold and excellent scratch resistance, so that even when the mold is pressed many times or when the cured film surface is subjected to blasting treatment to remove dirt, peeling of the cured film and scratching of the film surface are suppressed, and the number of times the cured film needs to be replaced can be reduced. Therefore, the injection molding of the thermosetting composition can be efficiently performed.

[0056] The injection molding method of the present embodiment can be suitably used, for example, for injection molding of a thermosetting composition for a reflector of an optical semiconductor. In the above-mentioned method for injection molding a thermosetting composition, the case where the holding portion 111 of the fixed mold 11 holds only the thermosetting composition has been described as an example, but the injection molding method of the present invention is not limited to this. For example, a lead frame may be placed on the holding portion 111 of the fixed mold 11, and a thermosetting composition for a reflector, which is the object to be molded, may be injected onto the lead frame so that the holding portion 111 holds the lead frame and the thermosetting composition. EXAMPLES

[0057] The present invention will be described in more detail below by way of examples, but the present invention is not limited to these examples.

[0058] Example 1 Components (A) to (F) shown in Table 1 were mixed and stirred at room temperature in the blending ratio shown in Table 1 to obtain a curable composition. The obtained composition was applied to the surface of an injection mold facing the molded article using a bar coater to a film thickness of about 8 μm, and cured using a UV curing device (product name: PSCC-60048A, manufactured by CCS Co., Ltd.) The mold on which the cured film was formed was then left to stand in an oven at 150° C. for 30 minutes to obtain a mold having a cured film on the surface facing the molded article.

[0059] Examples 2 to 15 A mold having a cured film was obtained in the same manner as in Example 1, except that components (A) to (F) were replaced with the components and blending ratios shown in Table 1 or 2.

[0060] Example 16 A composition was obtained in the same manner as in Example 1, except that the components (A) to (F) were replaced with the components and blending ratios shown in Table 1. The subsequent operations were the same as in Example 1, except that UV curing was not performed, to obtain a mold having a cured film.

[0061] Example 17 A composition was obtained in the same manner as in Example 1, except that components (A) to (F) were replaced with the components and blending ratios shown in Table 2. The subsequent operations were the same as in Example 1, except that the composition was not left to stand in an oven, to obtain a mold having a cured film.

[0062] Comparative Example 1 to Comparative Example 4 A mold having a cured film was obtained in the same manner as in Example 1, except that components (A) to (F) were changed to the components and blending ratios shown in Table 2.

[0063] Comparative Example 5 The mold was evaluated without forming a cured film on the surface of the mold.

[0064] <Evaluation> The molds obtained in Examples 1 to 17 and Comparative Examples 1 to 5 were used to carry out injection molding, and the occurrence of burrs, and scratches and peeling of the cured film were evaluated. The composition of the thermosetting composition to be molded is shown below. Isobornyl methacrylate (Light Ester IB-X, manufactured by Kyoeisha Chemical Co., Ltd.): 8 parts by mass Lauryl acrylate (SR355, manufactured by Arkema): 4 parts by weight Glycidyl methacrylate (Blenmer GH, manufactured by NOF Corporation): 2 parts by mass 1,10-Decanediol diacrylate (A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.): 6 parts by mass Spherical silica (average particle size (D50) 15 μm, CRS1085-SF630, manufactured by Tatsumori Co., Ltd.): 65 parts by weight Titanium oxide (average particle size 0.2 μm, PC-3, manufactured by Ishihara Sangyo Kaisha, Ltd.): 10 parts by weight Talc (average particle size 5 μm, TP-A25, manufactured by Fuji Talc Industries Co., Ltd.): 5 parts by weight Ultraviolet absorber (Tinuvin 765, manufactured by BASF Japan Ltd.): 0.5 parts by weight Zinc stearate (StZn, manufactured by Dainichi Chemical Industry Co., Ltd.): 1.5 parts by mass Fumed silica (average particle size 5 to 50 nm, R711, manufactured by Nippon Aerosil Co., Ltd.): 3 parts by mass Organic peroxide (Perhexa HC, manufactured by NOF Corporation): 1 part by mass

[0065] The thermosetting compositions were injection molded under the conditions shown below using the molds obtained in the Examples and Comparative Examples. (injection conditions) Molding machine: Liquid thermosetting resin injection molding machine LA-40S, manufactured by Sodick Co., Ltd. Low temperature section flow path temperature: 15℃ Flow path and heat blocking method: Uses shut-off nozzle High temperature part flow path temperature and cavity temperature: 130℃ Fill time: 10 seconds Filling pressure: 2MPa (filling time priority) Pressure retention time: 15 seconds Pressure during holding: 5MPa Curing time: 90 seconds

[0066] Injection molding was performed using each mold for 100 or more shots under the above conditions. The evaluation criteria for each item are shown below. (Flash in injection molded products) The injection molded products obtained were visually inspected to confirm the presence or absence of burrs. If no burrs were observed on the injection molded products even after 100 shots, the product was marked as "Good." If burrs were observed on the injection molded products within 100 shots, the product was marked as "Poor."

[0067] (Cure film peeling off) The condition of the mold and the cured film were visually observed after each shot. A case in which peeling of the cured film was not observed even after 100 shots was marked as "good", and a case in which peeling of the cured film occurred within 100 shots was marked as "bad".

[0068] (Scratches on the cured film) The condition of the cured film on the mold was visually observed after each shot. If no scratches were found on the cured film even after 100 shots, it was marked as "good", and if scratches were found on the cured film within 100 shots, it was marked as "bad". The evaluation results are shown in Tables 1 and 2.

[0069] [Table 1]

[0070] [Table 2]

[0071] Components (A) to (F) shown in Tables 1 and 2 are as follows. (Component (A)) A-1: 2-hydroxyethyl methacrylate acid phosphate (JPA-514, manufactured by Johoku Chemical Industry Co., Ltd.) A-2: 2-Acryloyloxyethyl acid phosphate (Light Acrylate P-1A(N), manufactured by Kyoeisha Chemical Co., Ltd.) ((B) component) B-1: Trimethylolpropane triacrylate (SR351S, manufactured by Arkema) B-2: Pentaerythritol tetraacrylate (SR295, manufactured by Arkema) B-3: Ethoxylated (3) trimethylolpropane triacrylate (SR454, manufactured by Arkema) B-4: Ethoxylated (6) trimethylolpropane triacrylate (SR499, manufactured by Arkema) ((C) component) C-1: Urethane acrylate (Art Resin UN-9000PEP, manufactured by Negami Chemical Industries, Ltd.) C-2: Urethane acrylate (Art Resin UN-7700, manufactured by Negami Chemical Industries, Ltd.) C-3: Urethane acrylate (Art Resin UN-9200A, manufactured by Negami Chemical Industries, Ltd.) ((D) component) D-1: Polyester acrylate (CN2283, Arkema) ((E) component) E-1: 1,1-di(t-amylperoxy)cyclohexane (Luperox 531M80, manufactured by Arkema Yoshitomi Co., Ltd.) E-2: 2-hydroxy-2-methyl-1-phenylpropanone (Omnirad1173, IGM resins BV) (Component (F)) F-1: 1,10-decanediol diacrylate (A-DOD-N, manufactured by Shin-Nakamura Chemical Co., Ltd., viscosity 10 mPa s at 25°C) F-2: 1,6-Hexanediol diacrylate (SR238F, Arkema, viscosity 9 mPa·s at 25°C) F-3: 1,9-nonanediol diacrylate (Viscoat #260, manufactured by Osaka Organic Chemical Industry Co., Ltd., viscosity 8 mPa s at 25°C)

[0072] As shown in Tables 1 and 2, in the examples, even after more than 100 shots, there were no scratches or peeling of the cured film, and all of the obtained injection molded articles were free of burrs and had good appearances. On the other hand, the cured film of the mold in Comparative Example 1 did not contain component (A), and therefore had insufficient adhesion to the mold, causing film peeling within 100 shots and burrs on the injection molded product. In addition, the cured film of the mold in Comparative Example 2 had insufficient surface hardness due to the low blending amount of component (B) of 25 parts by mass, and as a result, scratches were generated on the film within 100 shots and burrs were generated on the injection molded product. In addition, the cured film of the mold in Comparative Example 3 had an excessively high surface hardness and insufficient adhesion to the mold because the blending amount of component (B) was 72 parts by mass, which was too high. As a result, scratches and film peeling occurred within 100 shots, and burrs occurred on the injection molded product. Furthermore, since the cured film of the mold of Comparative Example 4 did not contain either component (C) or component (D), the strength of the cured film was insufficient, and burrs occurred on the injection molded product within 100 shots. [Industrial Applicability]

[0073] The curable composition of the present invention is suitably used, for example, as a raw material for a cured film that covers the surface of a mold used for molding a resin. The injection molding die and injection molding method of the present invention can be suitably used, for example, in injection molding of a thermosetting composition for a reflector of an optical semiconductor. [Explanation of symbols]

[0074] 10 Injection mold 11 Fixed mold 111 Holding part 12 Movable mold 121 Opposite Surface 122 Pressing part 200 Cured film

Claims

1. A mold for injection molding, comprising a cured film of a curable composition on at least a part of a surface facing a molded body, The curable composition comprises (A) a phosphate group-containing (meth)acrylate compound; (B) a polyfunctional (meth)acrylate compound having a molecular weight of less than 800 and being a trifunctional or tetrafunctional compound; (C) one or more selected from a urethane (meth)acrylate compound and (D) a polyester (meth)acrylate compound; The content of the (B) component is 30 to 70 parts by mass based on 100 parts by mass of the total of the components containing a (meth)acryloyl group. Injection molding die (however, a compound having three or more (meth)acryloyl groups in one molecule and having a phosphoric acid group is not included in the (B) polyfunctional (meth)acrylate compound, but is included in the (A) phosphoric acid group-containing (meth)acrylate compound, A urethane (meth)acrylate compound having three or more (meth)acryloyl groups in one molecule is not included in the (B) polyfunctional (meth)acrylate compound, but is included in the (C) urethane (meth)acrylate compound, A polyester (meth)acrylate compound having three or more (meth)acryloyl groups in one molecule is not included in the (B) polyfunctional (meth)acrylate compound, but is included in the (D) polyester (meth)acrylate compound.

2. The injection mold according to claim 1 , wherein the curable composition further comprises (E) a polymerization initiator.

3. The injection molding die according to claim 1 or 2, wherein the curable composition further contains (F) a (meth)acrylate compound having a viscosity of 100 mPa s or less at 25° C. as a (meth)acrylate compound other than the components (A) to (D).

4. A method for injection molding a thermosetting composition, comprising using the injection mold according to any one of claims 1 to 3.

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