JP2003137943A - Internal die coating composition and method for producing internal die coated molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal die coating composition having excellent curability and adhesiveness. SOLUTION: This internal die coating composition comprising (A) an oligomer having at least two (meth)acrylate groups, or an unsaturated polyester resin, (B) an ethylenic unsaturated monomer capable of copolymerizable with the component (A), and (C) an organic peroxide initiator having cross linking efficiency of >=8, is characterized in that the one minute half life temperature of the organic peroxide initiator (C) is 1.5×t[ deg.C], wherein the t[ deg.C] is the load- deflection temperature (1.82 MPa) of a resin molded article coated with the internal die coating composition. The method for producing the internal die coated article using the internal die coating composition is also provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an in-mold coating composition and a method for producing an in-mold coated molded product using the same.
In particular, the present invention relates to an in-mold coating composition for use in, for example, reaction injection molding (RIM molding) containing dicyclopentadiene as a main component, and injection molding of a thermoplastic resin such as ABS resin and polystyrene resin, and a composition thereof. Regarding usage.

[0002]

2. Description of the Related Art An in-mold coating method (in-mold coating method) in which coating is performed at the same time as molding in a mold, particularly in a mold is S
It is used to improve the surface quality of glass fiber reinforced thermosetting molding materials such as MC and BMC. In recent years, attempts have been made to apply the in-mold coating method to an injection molding method using a thermoplastic resin or the like. Such in-mold coating methods are disclosed, for example, in US Pat. No. 4,076,788 and US Pat. No. 4081.
578, US Pat. No. 4,331,735, US Pat. No. 4
No. 366109, US Pat. No. 4,668,460, JP-A-5-301251, JP-A-5-318527, and JP-A-8-142119. Further, the in-mold coating composition is disclosed in, for example, JP-A-05-1
17425, JP 05-331249 A,
It is disclosed in Japanese Patent Laid-Open No. 05-331250.

However, these coating compositions have high curing temperatures. Therefore, the conventional in-mold coating method using these coating compositions was applied to RI using dicyclopentadiene.
When M molding or injection molding using a thermoplastic resin such as ABS resin and polystyrene resin is attempted,
The present situation is that the coating composition does not cure or requires a long time even if it cures, and is practically impractical. Further, these coating compositions have a problem such as insufficient adhesion to a molding material.

[0004]

Therefore, the first aspect of the present invention
It is an object of the present invention to solve the above-mentioned conventional problems and provide an in-mold coating composition having excellent curability and adhesiveness. A second object of the invention is to provide a method of using such in-mold coating compositions. A third object of the present invention is to provide an in-mold coating composition having excellent light stability. A fourth object of the present invention is to provide an antistatic effect to the obtained resin molded product by using an in-mold coating composition containing a conductive pigment, and to provide a resin molded product which is easily subjected to electrostatic coating. To do.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to achieve the above object, and as a result, have found that the above object can be achieved by the following constitution, and arrived at the present invention. That is, the present invention relates to the following inventions. 1. (A) an oligomer having at least two (meth) acrylate groups, or an unsaturated polyester resin,
An in-mold coating composition containing (B) an ethylenically unsaturated monomer copolymerizable with the component (A), and (C) an organic peroxide initiator having a crosslinking efficiency of 8 or more, The 1-minute half-life temperature of the organic peroxide initiator (C) is 1.5 when the deflection temperature under load (1.82 MPa) of the resin molded product coated with the in-mold coating composition is t [° C]. × t [℃]
An in-mold coating composition, characterized in that:

2. (1) A step of molding a resin molded product by injection molding in a cavity formed by a mold that is separable into at least two and relatively accessible.
(2) After the molded product is hardened or solidified to withstand the injection pressure and the flow pressure of the in-mold coating composition, the molded product and the inner wall of the mold are provided with A method for producing an in-mold coated article, comprising the steps of injecting and curing the in-mold coating composition and (3) removing the coated article from the mold.

The present invention will be described in detail below.
The in-mold coating composition used in the present invention comprises the above-mentioned (A) an oligomer having at least two (meth) acrylate groups, or an unsaturated polyester resin, (B) the (A).
An ethylenically unsaturated monomer copolymerizable with the components, and (C) an organic peroxide initiator having a crosslinking efficiency of 8 or more are essential components, and if necessary, a release agent, a conductive pigment, etc. It contains optional components such as pigments, modified resins, antioxidants, ultraviolet absorbers, curing accelerators, various dispersants, and defoamers.

(1) Component (A) Component (A) used in the in-mold coating composition of the present invention is an oligomer having at least two (meth) acrylate groups, or an unsaturated polyester resin. Is. (1-1) has at least two (meth) acrylate groups
The oligomer having an oligomer at least two (meth) acrylate groups that, for example, urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylates, polyether (meth) acrylates, and silicone (meth) acrylate And the like. The weight average molecular weight of these oligomers may vary depending on their type, but in general,
About 300 to 10,000, preferably 500 to 5,0
A value of 00 is suitable. The oligomer having a (meth) acrylate group has a (meth) acrylate group
It is suitable to have at least 2, preferably 2 to 6, in one molecule.

(1-1-1) Urethane (meth) acrylate
Rigomer The urethane (meth) acrylate oligomer as an oligomer used in the present invention includes, for example, an organic diisocyanate compound, an organic polyol compound, and a hydroxyalkyl (meth) acrylate in NCO /
The OH ratio is, for example, 0.8 to 1.0, preferably 0.
It can be manufactured by an ordinary method by mixing in an abundance ratio of 9 to 1.0. An oligomer having a large number of hydroxyl groups can be obtained when the hydroxyl groups are present in excess or by using a large amount of hydroxyalkyl (meth) acrylate.

Specifically, an organic diisocyanate compound is reacted with an organic polyol compound or the like in the presence of a urethane-forming catalyst such as dibutyltin dilaurate to obtain an isocyanate-terminated polyurethane prepolymer. The urethane (meth) acrylate oligomer can then be prepared by reacting the hydroxyalkyl (meth) acrylate until most of the free isocyanate groups have reacted. In addition,
The ratio of the organic polyol compound and the hydroxyalkyl (meth) acrylate is appropriately about 0.1 to 0.5 mol of the former with respect to 1 mol of the latter.

Examples of the organic diisocyanate compound used in the above reaction include 1,2-diisocyanatoethane, 1,2-diisocyanatopropane, 1,3-diisocyanatopropane, hexamethylene diisocyanate and lysine diisocyanate. , Trimethylhexamethylene diisocyanate, tetramethylene diisocyanate, bis (4-isocyanatocyclohexyl) methane,
Methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 1,
3-bis (isocyanatomethyl) cyclohexane, 1,
3-bis (isocyanatoethyl) cyclohexane, 1,
3-bis (isocyanatomethyl) benzene, 1,3-bis (isocyanato-1-methylethyl) benzene, etc. can be used. These organic diisocyanate compounds can be used alone or as a mixture of two or more thereof.

Examples of the organic polyol compound, preferably the organic diol compound, used in the above reaction include alkyl diol, polyether diol, polyester diol and the like. Examples of the alkyl diol include ethylene glycol and 1,
3-propanediol, propylene glycol, 2,3
-Butanediol, 1,4-butanediol, 2-ethylbutane-1,4-diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1 , 9-nonanediol, 1,4-cyclohexanediol, 1,4-dimethylol cyclohexane, 4,8-dihydroxytricyclo [5.2.1.02,6] decane, 2,2-bis (4-hydroxy) Typical examples thereof include cyclohexyl) propane and the like. The polyether diol as the organic diol compound can be synthesized, for example, by a known method by polymerizing aldehyde, alkylene oxide, glycol or the like. For example, a polyether diol can be obtained by addition-polymerizing formaldehyde, ethylene oxide, propylene oxide, tetramethylene oxide, epichlorohydrin or the like with an alkyl diol under appropriate conditions. Examples of the polyester diol as the organic diol compound include esterification reaction products obtained by reacting saturated or unsaturated dicarboxylic acids and / or their acid anhydrides with an excess of alkyl diols, and alkyl diols. An esterification reaction product obtained by polymerizing a hydroxycarboxylic acid and / or a lactone which is an intramolecular ester thereof and / or a lactide which is an intermolecular ester can be used. The organic diol compounds listed above may be used alone or in combination of two or more.

Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. In addition, the urethane (meth) acrylate oligomer as the oligomer used in the present invention comprises a compound having a (meth) acrylate group and a hydroxyl group in one molecule, and an organic diisocyanate, and NCO / O.
The ratio of H is, for example, 0.9 to 1.0, and
It can also be produced by reacting in the presence of a urethanization catalyst such as dibutyltin dilaurate.

(1-1-2) Polyester (meth) acrylate Oligomer The polyester (meth) acrylate as an oligomer used in the present invention is, for example, a reaction between a polyester polyol having a hydroxyl group at the terminal and an unsaturated carboxylic acid. Can be manufactured by. Such a polyester polyol can be typically produced by subjecting a saturated or unsaturated dicarboxylic acid or its acid anhydride to an excess amount of an alkylene diol to carry out an esterification reaction. Typical examples of the dicarboxylic acid used include oxalic acid, succinic acid, adipic acid, phthalic acid, maleic acid and the like. Typical examples of the alkylene diol used include ethylene glycol, propylene glycol, butane diol, pentane diol, and the like. Here, as the unsaturated carboxylic acid, for example, acrylic acid, methacrylic acid and the like can be mentioned as typical ones.

(1-1-3) Epoxy (meth) acrylate oligomer The epoxy (meth) acrylate oligomer as the oligomer used in the present invention comprises, for example, an epoxy compound and the above unsaturated carboxylic acid, Carboxyl group equivalent per 1 equivalent of epoxy group, for example, 0.5 to
It was prepared by a usual ring-opening addition reaction of an acid to an epoxy group by using it at a ratio of 1.5. Suitable examples of the epoxy compound used here include bisphenol A type epoxy and phenolic novolac type epoxy. The polyether (meth) acrylate as an oligomer used in the present invention can be produced, for example, by reacting a polyether polyol such as polyethylene glycol or polypropylene glycol with the aforementioned unsaturated carboxylic acid. (1-1-4) Silicon (meth) acrylate oligomer Silicon (meth) as an oligomer used in the present invention
The acrylate oligomer is produced by, for example, an ester reaction between a hydroxyl group of an alcoholic siloxane compound and (meth) acrylic acid. silicon
The (meth) acrylate oligomer is particularly excellent in light stability or light resistance and is effective when used outdoors for a long period of time.

(1-2) Unsaturated Polyester Resin On the other hand, in the present invention, the unsaturated polyester resin used as the component (A) is, for example, an organic polyol,
It can be produced by reacting with an unsaturated polycarboxylic acid by a known method and, if necessary, reacting with a saturated polycarboxylic acid. Typical examples of the organic polyol used include ethylene glycol, propylene glycol, triethylene glycol, trimethylolpropane, glycerin, and bisphenol A. Further, as the unsaturated polycarboxylic acid used, for example, (anhydrous) maleic acid, (anhydrous) fumaric acid, (anhydrous) itaconic acid and the like can be mentioned as typical ones. As the component (A), the above (meth) acrylate group-containing oligomer and an unsaturated polyester resin may be used in combination.

(2) Component (B) The component (B) used in the present invention is an ethylenically unsaturated monomer that can be copolymerized with the component (A). Examples of such an ethylenically unsaturated monomer include styrene and α-methylstyrene,
Chlorostyrene, vinyltoluene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-
Ethylhexyl (meth) acrylate, ethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate , (Meth) acrylic acid amide,
N-vinyl-2-pyrrolidone, N-vinylcaprolactam, ethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,6
Typical examples include hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, triallyl isocyanurate and the like.
Preferably, tripropylene glycol diacrylate
(TPGDA), and aliphatic (meth) acrylate monomers such as 1,6-hexanediol diacrylate (1,6HDDA), and (meth) acrylate monomers having an alicyclic structure such as cyclohexyl methacrylate.

As the component (B), ethylenically unsaturated monomers may be used alone, or may be used as a mixture thereof. The ethylenically unsaturated monomer includes a hydroxyl group-containing ethylenically unsaturated monomer such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate as described above. The mass ratio of the component (A) to the component (B) depends on the kinds of compounds used as the component (A) and the component (B), but is usually (A) component: (B) component = 20. :
80-80: 20, preferably 33: 67-77: 2
3 is appropriate. Within this range, a coating composition having appropriate curing characteristics and viscosity can be obtained. In particular, the component (B) is used in an amount of 25 to 400 parts by mass, preferably 30 to 200 parts by mass, per 100 parts by mass of the component (A). When the amount of the component (B) is 25 parts by mass or more, a uniform coating can be obtained without the viscosity of the coating composition becoming too high and the fluidity in the mold being deteriorated, which is preferable. On the other hand, when the amount of the component (B) is 400 parts by mass or less, the viscosity of the coating composition does not become too low and air bubbles are not taken into the coating composition when flowing in the mold, and the composition is robust. This is preferable because a cured coating film can be obtained.

(3) Component (C) The component (C) used in the present invention is an organic peroxide polymerization initiator having a crosslinking efficiency of 8 or more, and is coated with the in-mold coating composition of the present invention. The organic peroxide initiator has a one-minute half-life temperature of 1.5 × t [° C] or less when the deflection temperature under load (1.82 MPa) of the resin molded product is set to t [° C].

(3-1) Crosslinking Efficiency The organic peroxide polymerization initiator of the present invention is one that generates a free radical and has a crosslinking efficiency of 8 or more, preferably 15 or more. That is, the coating composition covers the surface of the molded article in the mold, the organic peroxide polymerization initiator is thermally decomposed by the heat of the mold surface or the molding resin to generate radicals, and the coating composition undergoes a radical polymerization reaction, It is suitable that it is cured. The radicals generated by decomposition at that time also have different attacking forces on the oligomer or monomer depending on the structure, and the properties of the resulting cured coating film greatly change. Cross-linking efficiency is important as an index of this attack power. By efficiently reacting the radical polymerization reaction of the coating composition, the adhesiveness with the molding resin can be strengthened and the curing time can be shortened. It is effective to use this organic peroxide polymerization initiator having high crosslinking efficiency. The crosslinking efficiency is defined by the following measuring method. A certain amount of an organic peroxide initiator is added to n-pentadecane, and the initiator is decomposed by heating to generate radicals, and these radicals extract hydrogen in the pentadecane molecule according to their respective forces or attack forces, Generates pentadecyl radical. These pentadecyl radicals are recombined (crosslinking reaction) to form a dimer. (3-1-1) Measurement method 1) n-pentadecane and an organic peroxide initiator are injected into an ampoule. The concentration of the organic peroxide initiator is adjusted to 0.07 to 0.11 mol with respect to 100 mol of n-pentadecane. 2) Replace the air in the ampoule with He gas and seal it. 3) The organic peroxide initiator is completely decomposed by heating for 150 minutes (10 times the half-life) at a temperature at which the half-life of the organic peroxide initiator is 15 minutes. 4) Cool to room temperature and quantify the n-pentadecane dimer by gas chromatography. 5) From the amount of the obtained dimer, the amount of the dimer with respect to 1 mol of the organic peroxide initiator is calculated to obtain the crosslinking efficiency of the organic peroxide initiator. This measuring method follows the test method of Kayaku Akzo Co., Ltd., and the crosslinking efficiency is calculated by the following formula.

Examples of the organic peroxide initiator having a crosslinking efficiency of 8 or more include bis (4-t-butylcyclohexyl) peroxydicarbonate, t-amylperoxyl 2-ethylhexanoate and t-butyl. Peroxybenzoate, dicumyl peroxide, diisopropyl peroxy dicarbonate, di-2-ethylhexyl peroxy dicarbonate, t-octyl peroxy octoate, t-amyl peroxy octoate, t-
Butyl peroxy octoate, t-octyl peroxy benzoate, dibenzoyl peroxide, 1,1-
Di-t-butylperoxycyclohexane, t-butylperoxy-3,5,5-trimethylhexanoate,
Suitable examples include 2,2-di-t-butylperoxybutane, t-butylperoxyisopropyl carbonate, t-amylperoxybenzoate and the like.

(3-2) One-minute Half-life Temperature The organic peroxide initiator of the present invention has a predetermined one-minute half-life temperature. Specifically, the deflection temperature under load (1.82) of a resin molded product coated with the in-mold coating composition of the present invention.
MPa) is t [° C], the 1-minute half-life temperature of the organic peroxide initiator of the present invention is 1.5 x t [° C] or less, preferably 1.3 x t [° C] or less. , And more preferably 1.1 ×
It is t [° C] or less. 1-minute half-life temperature is 1.5 x t [° C]
The following conditions are preferable, because the curing time of the in-mold coating composition can be shortened below the mold temperature at which the resin molded product is not deformed. Here, the 1-minute half-life temperature means the ambient temperature when the concentration of the organic peroxide is reduced to half of the initial value in 1 minute, and is an index showing the decomposition rate with respect to the temperature of the organic peroxide initiator. . The lower the one-minute half-life temperature, the easier the decomposition. Here, the one-minute half-life temperature is defined as follows. That is, the half-life τ _{1/2 at} the temperature T (absolute temperature) is defined as follows. lnτ _1/2 = C−E / RT (1) where C: constant E: activation energy R: gas constant As a measuring method, first, benzene that is inactive to radicals is used, and 0.1 An organic peroxide solution having a concentration of .about.0.2 mol / liter is prepared and sealed in a glass tube which has been purged with nitrogen. Further, it is immersed in a constant temperature bath set at a predetermined temperature to thermally decompose it. Decomposing organic peroxide amount x, decomposition rate constant k, time t, and organic peroxide initial concentration a, lna / (ax) = kt (2) The half-life is as follows: since it is time to reduce the half, it shows the half-life in tau _1/2,
Substituting a / 2 for x in equation (2), kτ _1/2 = ln2 (3) Therefore, thermal decomposition is performed at a certain constant temperature, and time (t) to lna
/ (Ax) relationship is plotted, k is obtained from the slope of the obtained straight line, and half-life at that temperature is calculated from equation (3).
You can know (τ _1/2 ). On the other hand, in the decomposition of organic peroxide in an inert solvent, from the equation (1), the logarithm of the half-life τ _1/2 and 1 / T become a straight line, and the half-life at any number of temperatures is plotted. The half-life temperature in 1 minute can be calculated.

Further, the deflection temperature under load means that the resin molded product to be measured is heated at a constant speed while being subjected to bending stress.
It is an index showing the easiness of thermal deformation of the resin molded product when a certain amount of deflection is generated. Specifically, 1.82 MPa
Below, it is the value measured according to ISO75. The higher the deflection temperature under load, the higher the temperature stability of the resin molded product. As the measuring device, for example, an HDT test device
(Toyo Seiki Seisakusho Co., Ltd.).

The compounding amount of the organic peroxide initiator of the present invention is
0.2 to 20 parts by mass, preferably 0.5 to 10 parts by mass is suitable for 100 parts by mass of the component (A). When the blending amount of the organic peroxide initiator is 0.2 parts by mass or more, it is practical because a sufficient curing reaction can be performed without requiring a long time. On the other hand, when the compounding amount of the organic peroxide initiator is 20 parts by mass or less, a rapid reaction does not start in the mold, gelation does not occur during the flow, and a good molding material is obtained. Adhesion can be achieved.

(4) Conductive Pigment In the present invention, a conductive pigment can be optionally used in combination for imparting conductivity to the cured coating film. By adding a conductive pigment, it is possible to provide an antistatic effect and an electromagnetic wave shielding effect, and it is possible to provide a resin molded product that is easily electrostatically coated. As such a pigment, for example, carbon black, graphite, zinc oxide, titanium dioxide, or the like whose surface is coated with a conductive metal oxide such as antimony oxide, or carbon fiber can be used. The surface resistance of the cured coating film is, for example, 1 × 10 ⁻¹ to 1 × 10 ⁸ Ω · c.
m, preferably 1 × 10 ^{3 to} 9 × 10 ⁸ Ω · cm, and more preferably 1 × 10 ⁴ to 1 × 10 ⁶ Ω · cm. The compounding amount of the conductive pigment is (A),
It is suitable that the amount is, for example, 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass in total of the components (B) and (C).

(5) Release Agent In the present invention, a release agent can be optionally used in combination for smoothly releasing the cured coating film from the mold. The release agent has, for example, a melting point of 125 ° C. or lower, preferably 122.
Those having a liquid at a temperature of not more than 0 ° C., more preferably at room temperature, are suitable. When the melting point of the release agent is, for example, 125 ° C. or lower, a desired release effect can be sufficiently obtained. this is,
Even if the molding temperature is about 40 to 110 ° C., there is reaction heat associated with the curing of dicyclopentadiene or urethane, and a high melting AB of 200 to 240 ° C.
Considering that the S resin is cooled and solidified in the mold, the surface temperature of the molded product at the time of injecting the coating composition is considered to be sufficiently higher than the melting point of 125 ° C. of the release agent. is there. Examples of such a release agent include stearic acid, hydroxystearic acid, zinc stearate, aluminum stearate, magnesium stearate,
Examples thereof include stearates such as calcium stearate, soybean oil lecithin, silicone oil, fatty acid esters, and fatty acid alcohol dibasic acid esters. The compounding amount of the release agent is, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of the total of the components (A), (B) and (C).
Preferably, it is 0.2 to 3 parts by mass. Within this range, the releasing effect is suitably exerted.

(6) Pigment In the in-mold coating composition of the present invention, if necessary, various coloring pigments conventionally used for plastics and paints, and extender pigments may be used in combination as a pigment. it can. Examples of color pigments include titanium dioxide in white type, benzidine yellow or yellow type, benzidine yellow or titanium yellow, Hansa yellow, molybdate orange or orange type, benzidine orange or quinacridone in red type, and chrome green in green type. Or phthalocyanine green,
In blue, phthalocyanine blue, cobalt blue,
For ultramarine and black, pigments such as carbon black and iron oxide can be used. Further, the pigment may be a flake pigment such as mica treated with powdery or flake iron oxide, nickel, aluminum, graphite, titanium oxide or the like. Examples of extender pigments include calcium carbonate, talc, barium sulfate, aluminum hydroxide,
Suitable examples include clay. The pigment colors the molded product to give it an aesthetic appearance, disperses the shrinkage stress associated with film curing, improves adhesion to the molded product, smoothes the surface irregularities, and improves the appearance of the molded product surface. It is mixed for the purpose. In addition, in the case of clear finish, it is not always necessary to add a coloring pigment.

(7) Others In the in-mold coating composition of the present invention, if necessary, a polymethylmethacrylate resin, a saturated polyester resin,
Vinyl acetate resin, modified resin such as resin particles having a particle size of 0.1 to 30 μm, antioxidant, ultraviolet absorber, curing accelerator, pigment dispersant, various additives such as defoaming agent Good. The in-mold coating composition of the present invention is substantially solvent-free. It is preferable that the solvent is substantially not contained, since the solvent vapor is not taken into the in-mold coating composition during the flow in the mold to cause pinholes, and thus the coating film does not become brittle. Is. The phrase "substantially free" means, for example, even if it is included, it is at most less than 1%, and practically 0% of the mass of the coating composition. For example, when using a polyisocyanate compound, it is important to use one that does not substantially contain a solvent.

(8) Resin Molded Product As the synthetic resin molded product to which the in-mold coating composition of the present invention is applied, various conventionally known thermosetting molding materials and various thermoplastic synthetic resin molding materials are used. You can As the thermosetting molding material, for example, RIM molding material containing dicyclopentadiene as a main component, unsaturated polyester resin, epoxy acrylate resin, SMC containing phenol resin as a matrix, fiber reinforced plastic molding material called BMC, unsaturated R using a RTM molding material having a polyester resin or epoxy acrylate resin as a matrix, dicyclopentadiene, polyurethane, etc.
IM molding material etc. are mentioned. As the thermoplastic synthetic resin molding material, for example, polystyrene resin, polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene oxide resin, polyphenylene ether resin, polyamide resin, polyimide resin, polyvinyl chloride resin, polyvinyl acetate. Resin, ASA resin, ABS resin, AES resin, AS
A resin or various alloy materials of these resins are mentioned.
An alloy material is a composite material in which a thermoplastic synthetic resin as described above and one or more other polymers are physically mixed, and is generally understood to be a material having a synergistic effect on overall practical performance. ing. Such a thermoplastic resin molding material is, for example, an ultraviolet absorber, an antioxidant, a release agent, an antistatic agent, a colorant, a flame retardant, a plasticizer, or a glass so as to satisfy the characteristics according to the use. It may contain fiber reinforcing agents such as fibers, inorganic fillers and the like.

In the present invention, the compound having a hydroxyl group or a carboxyl group is preferably contained in the above-mentioned synthetic resin molded product, that is, the thermoplastic resin molding material and the thermosetting resin molding material. When the synthetic resin molded product contains such a functional group-containing compound, the adhesive force at the coating interface between the resin molded product and the in-mold coating composition is further strengthened. Such a functional group of the functional group-containing compound may be one existing in the molded article from the beginning, that is, a functional group of a synthetic resin containing a hydroxyl group, a carboxyl group or the like, or It may be produced by a reaction at the time of melt-kneading the synthetic resin molded product. Suitable examples of the compound having a hydroxyl group or a carboxyl group include the following.

A bisphenol A type vinyl ester resin containing a hydroxyl group, having a number average molecular weight of
For example, a thermosetting resin having a viscosity of 1000 to 2000, an ethylene / vinyl alcohol copolymer having a hydroxyl group, a styrene / maleic anhydride copolymer, and a carboxyl produced by esterification of a part of maleic anhydride. Styrene / maleic anhydride containing a group and having a copolymerization ratio of styrene and maleic anhydride of, for example, an equivalent ratio of 1: 1 to 3: 1 and a number average molecular weight of 1000 to 2000. The thermoplastic resin obtained by esterifying the acid copolymer with alkyl alcohol at a ratio of 35% to 75%, the content of methacrylic acid is, for example, 1 to 30% by mass.
Ethylene / methacrylic acid copolymer, which is a graft polymer having a comb structure, acid-modified acrylic / polystyrene polymer, polystyrene-grafted ethylene / glycidyl methacrylate copolymer, and 1-2 in the molecule
The number average molecular weight introduced with about hydroxyl groups is, for example, 5
Hydrogenated petroleum resins that are from 00 to 600. By adopting the coating composition of the present invention, the adhesive force at the interface between the thermosetting molding material or the thermoplastic resin molding material and the in-mold coating composition is improved, so that the adhesion which has been a problem in the past However, even in the case of resin molding materials that cannot be applied due to the problem of mold temperature, it is possible to perform in-mold coating that also has a function as an applicable top coating material.

(9) Method for Manufacturing In- Mold Coated Molded Article A constitution of a molding machine, a molding die and a coating composition injection device for carrying out the method for manufacturing an in-mold coated molded article of the present invention will be described below.
Although specifically described with reference to the drawings, the scope of the present invention is not limited by such a specific molding machine. FIG. 1 shows a method of carrying out a reaction injection molding method (RIM) using a molding material containing dicyclopentadiene as a main component as a thermosetting molding material. The upper die 1 and the lower die 2 are molding die members facing each other. The upper mold 1 and the lower mold 2 are fixed to a movable platen (not shown) and a fixed platen (not shown) of the mold clamping device, and the movable platen is moved forward and backward by a mold clamping cylinder (not shown). It is configured to be. A cavity 3 having a required shape is formed by both mold members 1 and 2, and a molding material containing dicyclopentadiene as a main component is filled therein and cured. The molding material containing dicyclopentadiene as a main raw material is filled in the cavity 3 by a device located on the left side in the drawing. Specifically, the temperature of the molding material is adjusted in the storage tanks 4 and 5, and then the pressure is increased to 5 to 50 MPa (50 to 500 bar) by the operation of the hydraulic cylinders 10 and 11 by the measuring cylinders 6 and 7. It is mixed by being jetted from the nozzles facing each other in the mixing head 13 and colliding with each other.

In the embodiment shown in FIG. 1, the coating composition comprises
In the drawing, injection is carried out by means of the device on the right, which comprises a mixing head 15 with a piston 14 having shut-off and injection functions, and the mixing head 1 described above.
5 are provided with metering cylinders 16 and 17 for supplying a predetermined amount of coating composition, and to these metering cylinders hydraulic cylinders 20 and 21 for pressurizing the coating composition are provided. The coating composition is ejected from the nozzles facing the mixing head 15 and is mixed by colliding with each other. Other methods for mixing the coating composition include, but are not limited to, a method using a static mixer, a method using a dynamic mixer, and an atomizing method.

When molding with the mold shown in FIG. 1, first, a mold clamping cylinder (not shown) is operated to close the upper mold 1 and the lower mold 2, and a mold clamping pressure is applied. This mold clamping pressure is
Usually, it is 0.3 to 1 MPa (3 to 10 Kgf / cm ² ). Next, a molding material (monomer) containing dicyclopentadiene as a main raw material is injected from the mixing head 13 into the cavity 3 and reacts in the mold to form a thermosetting resin molding. When the molding material is hardened in the mold to withstand the injection pressure and the flow pressure of the coating composition, the mold clamping pressure is maintained as it is, or is reduced or released.

Then, the mixed coating composition is injected immediately before the injection. In the case of injecting the coating composition, a liquid containing a resin main agent as a raw material of the coating composition as a main component and a liquid containing a curing agent for curing the main agent are stored in the raw material storage tanks 23 and 24 of the coating composition, respectively. After the temperature is adjusted by the measuring cylinders 16 and 17, the hydraulic cylinders 20 and 2 are
By the action of 1, the pressure is increased, and the pressure is ejected from the nozzles facing each other in the mixing head 15, and they are made to collide with each other and mixed. The coating composition is injected into the mixing head portion between the inner wall of the upper mold 1 and the surface of the synthetic resin molding material by the piston 14 also serving as a shutoff pin. in this way,
By mixing the raw material agent of the coating composition which reacts immediately before injection to form a coating composition, thickening or gelation does not occur as compared with the case of using a coating composition prepared by mixing in advance. It has good fluidity at the time and can prevent clogging of the injection device. After the injection of the raw material agent of the coating composition is completed, the mold clamping cylinder is operated and the mold clamping operation is performed as necessary to cure the coating composition in the mold. Then
The mold clamping cylinder is operated, the molds 1 and 2 are separated from each other, and the coated molded product is taken out from the mold.

FIG. 2 shows an embodiment of the thermoplastic resin molding material in the injection molding method. In FIG.
The movable platen 26 is configured to move to the right in the figure with respect to the fixed platen 25 of the mold clamping device of the injection molding machine.
An upper die 27 is joined to the fixed platen 25, while a lower die 28 is joined to the movable platen 26. The movable platen 26 is moved by the mold clamping cylinder 29,
It is configured to be able to move forward and backward in the left-right direction. Both types 27
And 28 are adapted to, when mated, form a cavity 30 of the required shape. The cavity 30 is filled with a molten or softened synthetic resin molding material,
Solidified. In the cavity 30, on the right side of the figure,
From an injection cylinder 31 having a screw to a nozzle 32
The molten synthetic resin molding material can be injected via the sprue 33. In addition, 34 is a boss part and 35 is an ejector pin at the time of mold release. A shear edge structure portion is formed at a fitting portion of the molding die members 27 and 28.

In FIG. 2, the coating composition is injected into the cavity 30 by means of the device located above in the figure. This apparatus comprises a mixing head 37 equipped with a piston 36 having shut-off and pouring functions, metering cylinders 38 and 39 for supplying the mixing head 37 with a predetermined amount of a raw material for a coating composition, and these metering cylinders being coated. Hydraulic cylinder 4 for pressurizing the raw material for the bed
2 and 43 are provided. Mixing head 37
In this case, the raw materials for the coating composition are jetted from the nozzles facing each other and are mixed by colliding with each other. Other methods for mixing the raw materials for the coating composition include a static mixer method, a dynamic mixer method, and an atomizing method, but the scope of the present invention is not limited thereto.

In molding, first, the mold clamping cylinder is operated to close the molds 27 and 28 and apply mold clamping pressure.
This mold clamping pressure is usually 29 to 98 MPa (300 to 10 MPa).
00 Kgf / cm ² ). Next, a molten resin made of a thermoplastic resin is injected from the injection cylinder 31 to the nozzle 32,
It is injected into the cavity 30 via the sprue 33. The molten resin is the injection pressure of the coating composition in the mold,
At the stage of solidification to withstand the flow pressure, the mold clamping pressure is maintained as it is, or the pressure is reduced or released.

The mixed coating composition is then injected just prior to injection. When injecting the coating composition, a liquid containing a resin main agent as a raw material of the coating composition as a main component and a liquid containing a curing agent for curing the main agent are stored in the raw material storage tanks 45 and 46 of the coating composition, respectively. After the temperature is adjusted, the pressure is increased to 5 to 50 MPa (50 to 500 bar) by the hydraulic cylinders 42 and 43 in the metering cylinders 38 and 39, and jetted from the opposing nozzles in the mixing head 37 and collide with each other to mix. To be done. In the mixing head 37, the coating composition is injected between the inner wall of the upper mold 27 and the surface of the synthetic resin molding material by the piston 36 that also serves as a shutoff pin. Thus, by mixing and coating the reacting raw material of the coating composition immediately before injection, thickening or gelation does not occur as compared with the case of using the coating composition prepared by mixing in advance, It has good fluidity during injection and can prevent clogging of the injection device. After the injection of the raw material agent of the coating composition is completed, the mold clamping cylinder is operated and the mold clamping operation is performed, if necessary, to cure the in-mold coating composition in the mold. Then, the mold clamping cylinder is operated to separate the molds 27 and 28 from each other, and the coated molded product is taken out from the mold.

[0040]

The present invention will be described in more detail based on the following examples and comparative examples, but the scope of the present invention is not limited to these examples and comparative examples. Example 1 and Comparative Example 1 A metal mold having a cavity for obtaining a resin molded product containing dicyclopentadiene as a main raw material in a box shape having a length of 400 mm, a width of 200 mm, and a height of 30 mm, according to the embodiment of FIG. In-mold coating was performed on the molded product. in this case,
The mold temperature was set to 95 ° C. for the upper mold 1 and 50 ° C. for the lower mold 2. First, the molding material containing dicyclopentadiene as the main raw material was clamped at a clamping pressure of 1 MPa (10 Kgf / cm ² ). It was injected into the mold and cured for 1 minute. Next, while maintaining the mold clamping pressure, each coating composition described in Table 1 below was weighed in a predetermined amount by the weighing cylinders 16 and 17, and the pressure was raised to 15 MPa (150 bar) by the hydraulic cylinders 20 and 21, and the mixing head was used. It jetted from the nozzle which opposed in 15 and mixed by colliding with each other. 20 cm ^{3 of} each coating composition described in Table 2 was provided between the inner wall of the upper mold 1 and the surface of the dicyclopentadiene molded product by the piston 14 also serving as a shutoff pin in the mixing head 15.
Was injected. After holding for 2 minutes after completion of the injection, both molds 1 and 2 were separated from each other, and the molded product was taken out from the mold. Table 2 below shows the appearance of the obtained molded product and the evaluation results of the adhesion of the coating composition.

[0041]

[Table 1] Table 1 (unit: parts by mass)

Note) Dicyclopentadiene molded product Deflection temperature under load (1.82 MPa) = 100 ° C. UAC-1 (corresponding to component (A)) 1 mol of isophorone diisocyanate and Praxel FM
-3 (manufactured by Daicel Chemical Industries, Ltd.) [a reaction product (hydroxyl group-containing urethane oligomer)] with 1.8 mol of a compound having a number average molecular weight of 472 having one methacryloyl group in a polycaprolactone oligomer and one primary hydroxyl group (a urethane oligomer containing a hydroxyl group) ( There are two methacryloyl groups in the molecule). UAC-2 (corresponding to the component (A) ) 2 mol of bis (4-isocyanatocyclohexyl) methane, ethylene oxide adduct of 2,2-bis (4-hydroxycyclohexyl) propane (number average molecular weight 1,
000) 1 mol, a urethane methacrylate oligomer synthesized from 2.1 mol of 2-hydroxyethyl methacrylate (methacryloyl groups are 2 in the molecule) TPGDA (corresponding to the component (B)) tripropylene glycol diacrylate 1,6HDDA (( Corresponding to component B) 1,6 hexanediol diacrylate bis (4-t-butylcyclohexyl) peroxydicarbonate (corresponding to component (C)) Crosslinking efficiency 24.0, 1-minute half-life temperature 92 ° C dioctanoyl Peroxide (Compatible with (C) component (ratio
Comparative example) Crosslinking efficiency 5.5, 1 minute half-life temperature 116 ° C Carbon black (corresponding to (4) conductive pigment) Vulcan XC-72R (manufactured by Cabot) ZELEC-NE (corresponding to (5) release agent) ) Neutralizable phosphate alcohol (manufactured by DuPont) titanium dioxide (corresponding to (6) color pigment) disperbyk-110 (corresponding to (7) and others) pigment dispersant (manufactured by BYK Chemie)

[0043]

[Table 2] Table 2

Note 1) The case where there is no abnormality such as unevenness of the coated surface, spots, wrinkles, blisters, and cracks visually under diffused daylight is considered good. Note 2) According to JIS K 5400 8.5.2 cross-cut cellophane tape method. However, the interval between cuts is 1 mm,
The number of squares is 100. Evaluation criteria: Best 10 → Worst 0 Note 3) Gloss retention rate (%) after 1 year exposure test at 45 degrees southwest of Okinawa area. Gloss retention rate is JIS K 54
00 7.6 The glossiness when the incident angle and the light receiving angle of the specular glossiness were 60 degrees was measured and calculated before and after the exposure test.

Example 2 and Comparative Example 2 A mold having a cavity for obtaining a box-shaped synthetic resin molded product having a length of 300 mm, a width of 300 mm, and a height of 30 mm, according to the embodiment of FIG. The coating was carried out. In this case, the mold temperature is set to 90 ° C., the barrel temperature is heated to 200 ° C., the ABS resin is first heated and melted in the injection cylinder, and the mold resin is clamped at a mold clamping pressure of 550 tons. Injection was carried out over 2 seconds and cooled for 40 seconds, and the surface of the obtained molded product was solidified to such an extent that it could withstand the pouring and flowing pressure of the coating composition. Then, after separating the movable mold by about 1 mm, 10 cm ^{3 of} each coating composition shown in Table 3 was injected between the mold surface and the surface of the molded product for about 0.5 seconds. After the injection was completed, the mold clamping pressure was increased to 10 tons over 1 second and kept for 5 seconds. Then, the mold clamping pressure was increased to 20 tons and held for 85 seconds to cure the coating composition. The composition of the coating composition is shown in Table 3 below. Further, the results of evaluating the appearance of the obtained molded article and the adhesiveness of the coating composition in the same manner as in Example 1 are shown in Table 4 below.

[0046]

[Table 3] Table 3 (unit: parts by mass)

Note) ABS resin deflection temperature under load (1.82 MPa) = 93 ° C. t-aluminum peroxyl 2-ethylhexanoate
(Compatible with (C) component) Crosslinking efficiency 15.0, 1-minute half-life temperature 127 ° C TINUVIN123 (Compatible with (7) antioxidant) TINUVIN400 ( Compatible with (7) UV absorber)

[Table 4] Table 4

Example 3, Comparative Example 3 A mold having a cavity for obtaining a box-shaped synthetic resin molded product having a length of 300 mm, a width of 300 mm, and a height of 30 mm, according to the embodiment of FIG. The coating was carried out. In this case, the mold temperature is set to 95 ° C., the barrel temperature is heated to 200 ° C., the ABS resin is first heated and melted in the injection cylinder, and the mold is clamped at a mold clamping pressure of 550 tons. Injection was carried out over 2 seconds and cooled for 40 seconds, and the surface of the obtained molded product was solidified to such an extent that it could withstand the pouring and flowing pressure of the coating composition. Then, after separating the movable mold by about 1 mm, 10 cm ^{3 of} each coating composition shown in Table 5 was injected between the mold surface and the surface of the molded product for about 0.5 seconds. After the injection was completed, the mold clamping pressure was increased to 10 tons over 1 second and kept for 5 seconds. Then, the mold clamping pressure was increased to 20 tons and held for 85 seconds to cure the coating composition. The composition of the coating composition is shown in Table 5 below. Further, the results of evaluating the appearance of the obtained molded product and the adhesiveness of the coating composition in the same manner as in Example 1 are shown in Table 6 below.

[0049]

[Table 5] Table 5 (unit: parts by mass)

Note) t-butylperoxybenzoate (paired with component (C))
C ) Crosslinking efficiency 40.0, 1-minute half-life temperature 169 ° C Dicumyl peroxide (corresponding to component (C)) Crosslinking efficiency 51.0, 1-minute half-life temperature 179 ° C

[Table 6] Table 6

[0051]

According to the present invention, it is possible to provide an in-mold coating composition having excellent curability and adhesiveness. By adopting such an in-mold coating composition, it becomes possible to shorten the curing time of the in-mold coating composition. The in-mold coating composition of the present invention can also be applied to resin molding materials for which the in-mold coating method cannot be applied due to problems of adhesion and molding and curing time. In addition, the in-mold coating composition of the present invention also functions as a topcoat paint, and can provide a resin molded product excellent in appearance and weather resistance. Further, by using this in-mold coating composition, a simple and practically excellent method for producing a coated molded article is provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of one RIM molding apparatus suitable for forming a coated molding using the in-mold coating composition of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of another injection molding apparatus suitable for forming a coated molding using the in-mold coating composition of the present invention.

[Explanation of symbols]

1, 2, 27, 28 Mold member 3, 30 Cavity 4, 5, 45, 46 Coating composition raw material storage tank 6, 7, 38, 39 Measuring cylinder 13, 37 Mixing head

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 4/00 C09D 4/00 5/24 5/24 // B05D 7/22 B05D 7/22 Z B29K 23 : 00 B29K 23:00 67:00 67:00 105: 16 105: 16 C08L 101: 00 C08L 101: 00 F term (reference) 4D075 AC88 CA13 CA22 CA32 CA47 CB04 DA19 DA23 DA29 DB01 DB35 DB36 DB37 DB38 DB40 DB42 DB43 DB46 DB47 DB48 DB49 DB50 DB53 DB55 DB61 EA07 EB14 EB19 EB20 EB22 EB24 EB33 EB35 EB38 EB43 EC07 EC11 EC37 EC51 EC60 4F006 AA04 AA12 AA15 AA17 AA20 AA31 AA33 AA34 AA35 AA36 AA37 AA38 AA39 AB43 AB72 AB74 BA07 4F206 AA04 AA24 JA01 JA07 JB23 JB24 JF01 JF22 JF41 JL02 JM04 JM06 JN12 JN35 JQ81 4J027 AB05 AB06 AB07 AB10 AB15 AB16 AB18 AB23 AB24 AB25 AE02 AE03 AF05 AG01 BA05 BA07 BA10 BA13 BA14 BA15 BA22 BA24 BA26 BA29 CA12 CA20 CA29 CA33 CB03 CC02 CD01 4J038 CB171 CB172 CC021 CC022 CF021 CF022 CG141 CG142 CG161 CG162 CG171 CG172 CH031 CH032 CH041 CH042 CH121 CH122 DD051 DD052 DF021 DF022 DG261 DG262 FA041 FA042 FA061 FA062 FA111 FA112 FA151 FA152 FA161 FA162 FA211 FA212 FA251 FA252 FA261 FA262 FA271 FA272 FA281 FA282 GA03 JA66 KA08 KA12 LA02 MA14 NA12 NA20 NA24 PC08

Claims (5)

[Claims] 1. An (A) oligomer having at least two (meth) acrylate groups, or an unsaturated polyester resin, (B) an ethylenically unsaturated monomer copolymerizable with the (A) component, and (C). An in-mold coating composition containing an organic peroxide initiator having a crosslinking efficiency of 8 or more,
When the deflection temperature under load (1.82 MPa) of the resin molded product coated with the in-mold coating composition is t [° C]
(C) The one-minute half-life temperature of the organic peroxide initiator is 1.5
An in-mold coating composition, characterized in that it is not more than × t [° C]. 2. The component (B) contains at least one aliphatic (meth) acrylate monomer.
The in-mold coating composition described in 1. 3. The in-mold coating composition according to claim 1, wherein the component (B) contains at least one (meth) acrylate monomer having an alicyclic structure. 4. The method according to claim 1, further comprising a conductive pigment.
The in-mold coating composition according to any one of 3 above. 5. (1) In a cavity formed of a mold that is separable into at least two and is relatively accessible,
A step of molding a resin molded product by injection molding, (2) after the molded product is cured or solidified to such an extent that it can withstand the injection pressure and flow pressure of the in-mold coating composition according to claim 1, In, the step of injecting the in-mold coating composition between the molded article and the inner wall of the mold and curing the composition, and (3) removing the coated molded article from the mold are included. A method for producing a molded article covered with a mold.