JP4832513B2 - Reaction injection molded body having a coating film on the surface and method for producing the same - Google Patents

Description

  The present invention relates to a reaction injection molded body having a coating film on its surface and a method for producing the same. More specifically, the present invention relates to a reaction injection molded body having a coating film free from coating defects, and a method for producing a reaction injection molded body having a coating film free from coating defects by in-mold coating subsequent to reaction injection molding.

Large molded products used for automobile parts such as bumpers and air deflectors, construction and industrial machinery such as wheel loaders and power shovels, leisure equipment such as golf cars and game machines, and housing equipment such as wash bowls and unit baths, etc. Recently, it is manufactured by reaction injection molding. In order to impart characteristics such as designability and weather resistance to the resin molded body used in each of these applications, a coating film is formed.
For the formation of this coating film, the surface of a resin molded body obtained by bulk polymerization of a reaction stock solution composed of a monomer, a catalyst, and the like in a mold has been spray-coated by a reaction injection molding method (RIM method). The method has been adopted.

However, the resin molded body in which the coating film is formed by this method has a problem in that the adhesiveness of the coating film is lowered due to a change with time and the production cost is high.
As a method for solving this problem, an in-mold coating method is known. When a molded body is manufactured by the reaction injection molding method, the volume shrinks when the reaction stock solution becomes a molded body. Although this is called molding shrinkage, a gap of 5 to 500 μm is usually generated between the mold and the molded body due to the molding shrinkage. The in-mold coating method is a method in which a coating agent is injected into a gap between a molded body and a mold surface generated by the molding shrinkage and is cured to form a coating film on the molded body. After the in-mold coating, the molded body having the coating film is taken out from the mold.
However, when this in-mold coating method is applied to a basin-shaped body such as a washing basin pan of a unit bath, the coating agent does not easily enter the vertical wall portion of the basin-shaped body, and therefore this part has a particularly good coverage. It may not be possible to form a cover film.

In Patent Document 1, in addition to specifying the timing from the end of bulk polymerization of the reaction stock solution used for reaction injection molding to the start of coating agent injection, the thickness of the vertical wall, the formation position of the rib, etc. are specified ranges, respectively. It has been reported that the use of a coating can prevent the coating from being poorly coated and the generation of wrinkles and cracks.
However, depending on the shape of the molded body, it may be impossible to adjust the thickness of the vertical wall, or the formation of ribs may be undesirable. Can not.
Patent Document 2 discloses that a molded product obtained by reaction injection molding is fixed by a molded product fixing means, and a coating agent is injected into the mold and cured to form a coating film on the surface of the molded product. A method of forming is disclosed.
However, depending on the shape of the molded product, fixing may not be sufficient, and application defects may occur.

JP 2003-11152 A International Publication No. 2005/046958 Pamphlet

  Therefore, an object of the present invention is to provide a reaction injection that can obtain a reaction injection molded body having a uniform coating film without forming a rib or the like on the molded body or without providing a molded product fixing means. It is providing the manufacturing method of a molded object. Another object of the present invention is to provide a reaction injection molded article by the above production method.

  As a result of diligent research on the composition of the reaction injection molding material in order to achieve the above object, the present inventors have found that a reaction injection molded body contains a specific inorganic filler. As a result, it was found that a reaction injection-molded article having a good coating film can be obtained, and the present invention has been completed based on this finding.

Thus, according to the present invention, the polymerization property comprising a norbornene monomer, a polymerization catalyst, and an inorganic filler comprising a fibrous filler having an aspect ratio of 5 to 100 and a particulate filler having an aspect ratio of 1 to 2. A composition is obtained by bulk polymerization in a mold to obtain a molded body, and subsequently a coating film is formed on the surface of the molded body by an in-mold coating method in the mold. A method for producing a reaction injection molded body is provided.
In the method for producing a reaction injection molded article of the present invention, it is preferable to use a metathesis polymerizable composition as the polymerizable composition.
In the method for producing a reaction injection molded article of the present invention, the content weight ratio (fibrous filler / particulate filler) of the fibrous filler and the particulate filler is 95/5 to 55/45. preferable.
In the method for producing a reaction injection molded article of the present invention, the fibrous filler preferably has a 50% volume cumulative diameter of 0.1 to 50 μm.
In the method for producing a reaction injection molded article of the present invention, it is preferable that the particulate filler has a 50% volume cumulative diameter of 0.1 to 50 μm.
In the method for producing a reaction injection molded article of the present invention, the fibrous filler having an aspect ratio of 5 to 100 is preferably wollastonite or whisker-like calcium carbonate.
In the method for producing a reaction injection molded article of the present invention, the particulate filler having an aspect ratio of 1 to 2 is preferably calcium carbonate or calcium hydroxide.
In the method for producing a reaction injection molded article of the present invention, the amount of the inorganic filler is preferably 5 to 55 parts by weight with respect to 100 parts by weight of the total amount of the norbornene monomer and the catalyst.
Furthermore, according to the present invention, there is provided a reaction injection molded article comprising a bulk polymer of norbornene-based monomers containing an inorganic filler, which is obtained by the method for producing a reaction injection molded article, and having a coating film on the surface thereof. Provided.
The reaction injection molded article of the present invention is preferably a large panel.

According to the present invention, it is possible to obtain a reaction injection molded article having a uniform coating film without requiring the formation of ribs on the molded article or without using a molded article fixing means. it can.
The reaction injection molded article having a coating film obtained in the present invention is used for automobiles such as bumpers and air deflectors, construction and industrial machinery applications such as wheel loaders and power shovels, leisure applications such as golf carts and game machines, and medical treatments. It can be suitably used in medical applications such as equipment, industrial applications such as large panels and chairs, and residential equipment applications such as shower pans and wash bowls.

  The method for producing a reaction injection molded body having a coating film on the surface according to the present invention comprises a norbornene monomer, a polymerization catalyst, a fibrous filler having an aspect ratio of 5 to 100, and a particulate filling having an aspect ratio of 1 to 2 A polymerizable composition containing an inorganic filler made of a material is bulk-polymerized in a mold to obtain a molded body, and subsequently a coating film is formed on the surface of the molded body by an in-mold coating method in the mold. It is characterized by.

The polymerizable composition used in the present invention contains a norbornene monomer, a polymerization catalyst, and an inorganic filler.
The norbornene-based monomer may be any as long as it has a norbornene ring. Specific examples thereof include bicyclic compounds such as norbornene and norbornadiene; tricyclic compounds such as dicyclopentadiene and dihydrodicyclopentadiene; tetracyclododecene and the like. And tetracyclics; pentacyclics such as cyclopentadiene trimers; and heptacyclics such as cyclopentadiene tetramers. These bicyclic to heptacyclic rings have hydrocarbon groups such as alkyl groups, alkenyl groups, alkylidene groups, and aryl groups, and polar groups such as ester groups, ether groups, cyano groups, and halogen atoms as substituents. It may be. Among them, a tricyclic or higher polycyclic norbornene monomer is preferable because it is easily available and has excellent reactivity, and a tricyclic to pentacyclic norbornene monomer is more preferable.

Specific examples of the norbornene-based monomer include dicyclopentadiene, tricyclopentadiene, cyclopentadiene-methylcyclopentadiene co-dimer, 5-ethylidene norbornene, norbornene, norbornadiene, 5-cyclohexenyl norbornene, 1,4,5,8 Dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 1,4-methano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6 -Ethylidene-1,4,5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4-methano-1,4,4a, 5 , 6,7,8,8a-octahydronaphthalene, 1,4,5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydrona Array type, ethylenebis (5-norbornene), and the like.
Norbornene monomers may be used alone or in combination of two or more.
In addition, monocyclic cycloolefins such as cyclobutene, cyclopentene, cyclopentadiene, cyclooctene, and cyclododecene can be used as a comonomer.

The polymerization catalyst is preferably a metathesis polymerization catalyst.
The metathesis polymerization catalyst is not particularly limited as long as it is a catalyst capable of ring-opening polymerization of a norbornene-based monomer.
The metathesis polymerization catalyst is a complex formed by bonding a plurality of ions, atoms, polyatomic ions and / or compounds with a transition metal atom as a central atom. As transition metal atoms, atoms of Groups 5, 6 and 8 (long period periodic table, the same applies hereinafter) are used. Although the atoms of each group are not particularly limited, examples of the Group 5 atom include tantalum, examples of the Group 6 atom include molybdenum and tungsten, and examples of the Group 8 atom include: Examples include ruthenium and osmium.

Metathesis polymerization catalysts having group 6 tungsten or molybdenum as the central metal include metal halides such as tungsten hexachloride; metal oxyhalides such as tungsten chlorine oxide; metal oxides such as tungsten oxide; and tridodecylammonium Organometallic acid ammonium salts such as molybdate and tri (tridecyl) ammonium molybdate can be used.
In these, the organic molybdate ammonium salt is preferable. When these metathesis polymerization catalysts are used, it is preferable to use an organoaluminum compound or an organotin compound as an activator (cocatalyst) for the purpose of controlling the polymerization activity.

In the present invention, it is also preferable to use a metal carbene complex having a metal atom of Groups 5, 6 and 8 as a central metal as a metathesis polymerization catalyst. Of the metal carbene complexes, Group 8 ruthenium and osmium carbene complexes are preferred, and ruthenium carbene complexes are particularly preferred. This is because the activity of the catalyst at the time of bulk polymerization is excellent, so that the productivity of the norbornene-based resin molded body is excellent, and the resulting norbornene-based resin molded body has little odor derived from the unreacted norbornene-based monomer.
Among the ruthenium carbene complexes, a ruthenium carbene complex in which at least two carbene carbons are bonded to a ruthenium metal atom and a group containing a hetero atom is bonded to at least one of the carbene carbons is particularly preferable.

  The amount of the metathesis polymerization catalyst used is usually 0.01 mmol or more, preferably 0.1 mmol or more, and 50 mmol or less, preferably 20 mmol or less with respect to 1 mol of the monomer used in the reaction. If the amount of metathesis polymerization catalyst used is too small, the polymerization activity will be too low and the reaction will take a long time, resulting in poor production efficiency. If the amount used is too large, the reaction will be so intense that it will cure before it is fully filled in the mold Or the catalyst is likely to be deposited, and it is difficult to store it homogeneously.

  The activator (cocatalyst) is not particularly limited, and specific examples thereof include organometallic compounds of metals in Groups 11 to 14 of the periodic table. Specific examples thereof include organoaluminum compounds such as alkylaluminum halides such as ethylaluminum dichloride and diethylaluminum chloride and alkoxyalkylaluminum halides; organotin compounds such as tetrabutyltin; and the like. In addition, when using a ruthenium carbene complex as a metathesis polymerization catalyst, it is not necessary to use an activator.

The amount of the activator used is not particularly limited, but is usually 0.1 mol or more, preferably 1 mol or more, and 100 mol or less, preferably 10 mol or less with respect to 1 mol of the metathesis polymerization catalyst used in the reaction. It is. If no activator is used or if the amount of activator used is too small, the polymerization activity is too low and the reaction takes time, resulting in poor production efficiency. On the other hand, when the amount used is too large, the reaction is too intense, and the polymerizable composition may be cured before being sufficiently filled in the mold.
The activator is used after being dissolved in the monomer, but within a range that does not substantially impair the properties of the molded article by the reaction injection molding method, it is suspended in a small amount of solvent and then mixed with the monomer. You may use it, making it difficult to precipitate or improving solubility.

Moreover, it is preferable to add an activity regulator. As will be described later, the activity regulator is used to prevent polymerization from starting in the middle of the injection when the polymerization catalyst monomer solution and the activator monomer solution are mixed and injected into the mold. It is.
As such an activity regulator, Lewis base is suitable, and ether, ester, nitrile and the like are used. Specific examples include butyl ether, ethyl benzoate, diglyme and the like. When a polar group-containing monomer is used as a copolymerization monomer, the monomer itself may be a Lewis base and may also have an action as an activity regulator. The activity regulator is preferably added to a solution containing the active agent. Moreover, alcohols can also be used suitably as an activity regulator.
Furthermore, it is preferable to add a polymerization accelerator in order to improve the polymerization conversion of the monomer. As the polymerization accelerator, a chlorine atom-containing compound is preferable, and among them, an organic chlorine compound and a chlorinated silicon compound are preferable. Specific examples thereof include hexachloro-p-xylene, 2,4-dichloro-trichlorotoluene, silicon tetrachloride and the like.
Although the addition amount of the said activity regulator and a polymerization accelerator is not specifically limited, Each is about 10 ppm-10% of the polymeric composition weight.

In the present invention, an inorganic filler composed of a fibrous filler having an aspect ratio of 5 to 100 and a particulate filler having an aspect ratio of 1 to 2 is used as an essential component of the polymerizable composition.
In the present invention, the aspect ratio of the filler refers to the ratio between the average major axis diameter of the filler and the 50% volume cumulative diameter. Here, the average major axis diameter is a number average major axis diameter calculated as an arithmetic average value obtained by measuring the major axis diameters of 100 fillers randomly selected from an optical micrograph.
The 50% volume cumulative diameter is a value obtained by measuring the particle size distribution by the X-ray transmission method.

The content weight ratio (fibrous filler / particulate filler) of the fibrous filler and the particulate filler is preferably 95/5 to 55/45, and more preferably 80/20 to 60/40. More preferred.
When this ratio is within the above range, it becomes easier to obtain a molded body having a coating film free from coating film defects.

The fibrous filler used in the present invention is essential to have an aspect ratio of 5 to 100, and preferably has an aspect ratio of 10 to 50.
The 50% volume cumulative diameter of the fibrous filler is preferably 0.1 to 50 μm, more preferably 1 to 30 μm. If the 50% volume cumulative diameter is too small, the rigidity and dimensional stability of a molded product obtained using this may become insufficient. Conversely, if the 50% volume cumulative diameter is too large, the polymerization reaction solution may settle in the tank or piping or the injection nozzle may be clogged when the polymerization reaction solution is injected into the mold.

Specific examples of the fibrous filler include glass fiber, wollastonite, potassium titanate, zonolite, basic magnesium sulfate, aluminum borate, tetrapod type zinc oxide, gypsum fiber, phosphate fiber, alumina fiber, whisker-like carbonic acid. Calcium, whisker-like boehmite and the like can be mentioned.
Among these, wollastonite and whisker-like calcium carbonate that can increase the rigidity of the resulting molded body with a small amount of use without inhibiting bulk polymerization are preferable.

The particulate filler used in the present invention is essential to have an aspect ratio of 1 to 2, and preferably has an aspect ratio of 1 to 1.5.
The 50% volume cumulative diameter of the particulate filler is preferably 0.1 to 50 μm, more preferably 1 to 30 μm, and particularly preferably 1 to 10 μm. If the 50% volume cumulative diameter is too small, the rigidity and dimensional stability of a molded product obtained using this may become insufficient. Conversely, if the 50% volume cumulative diameter is too large, the polymerization reaction solution may settle in the tank or piping or the injection nozzle may be clogged when the polymerization reaction solution is injected into the mold.

Specific examples of the particulate filler include calcium carbonate, calcium hydroxide, calcium silicate, calcium sulfate, aluminum hydroxide, magnesium hydroxide, titanium oxide, zinc oxide, barium titanate, silica, alumina, carbon black, graphite , Antimony oxide, red phosphorus, various metal powders, clay, various ferrites, hydrotalcite and the like.
Of these, calcium carbonate and calcium hydroxide are preferred because they do not inhibit the bulk polymerization reaction.

It is preferable that the filler used in the present invention has a hydrophobic surface. By using the hydrophobized filler, aggregation and sedimentation of the filler in the polymerizable composition can be prevented, and dispersion of the filler in the resulting molded article can be made uniform, thereby forming the molding. The rigidity and dimensional stability of the body can be made uniform, and the anisotropy can be reduced.
Examples of the treating agent used for the hydrophobizing treatment include silane coupling agents such as vinyl silane, titanate coupling agents, aluminum coupling agents, fatty acids such as stearic acid, fats and oils, surfactants, and waxes.
The hydrophobic treatment of the filler can be performed by mixing the hydrophobic treatment agent at the same time when preparing a polymerizable composition comprising a norbornene-based monomer, a polymerization catalyst and a filler. It is preferable to prepare the polymerizable composition using the filler that has been subjected to the chemical treatment.

In the present invention, the amount of the inorganic filler is preferably 5 to 55 parts by weight, and more preferably 10 to 45 parts by weight with respect to 100 parts by weight of the total amount of the norbornene monomer and the catalyst.
If the amount of the inorganic filler is too large, it may settle in the tank or piping when the reaction solution is injected into the mold or the injection nozzle may be clogged. On the other hand, if the amount is too small, the resulting molded article may have insufficient rigidity and dimensional stability.

In the present invention, in order to improve or maintain the properties of the molded product, various additives may be added to the polymerizable composition as long as the adhesiveness and adhesion between the cured coating and the molded product are not impaired. Good. Such additives include reinforcing materials, antioxidants, heat stabilizers, light stabilizers, UV absorbers, pigments, colorants, foaming agents, antistatic agents, flame retardants, lubricants, softeners, tackifiers, plasticizers. Agents, mold release agents, deodorants, fragrances, elastomers, dicyclopentadiene-based thermal polymerization resins and hydrogenated products thereof.
In particular, by adding an elastomer, the viscosity of the reaction stock solution can be adjusted, and the impact resistance of the resulting molded product can be improved. Examples of the elastomer include natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer (SBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), Mention may be made of ethylene-propylene-diene terpolymers, ethylene-vinyl acetate copolymers (EVA) and their hydrides.
The usage-amount of an elastomer is 0.5-20 weight part normally with respect to 100 weight part of norbornene-type monomers, Preferably it is 2-10 weight part.

  Various additives are added to the catalyst or activator monomer solution; used as a separate monomer solution and mixed with the catalyst or activator monomer solution during reaction injection molding; It is added by the method; What is necessary is just to select suitably the addition method with the kind of additive.

A method for preparing a polymerizable composition comprising a norbornene-based monomer, a polymerization catalyst, and an inorganic filler is not particularly limited, and these components may be mixed by any method. Depending on whether or not the catalyst requires an activator (cocatalyst), the following two methods can be shown.
That is, when the polymerization catalyst does not require an activator, the reaction stock solution (i) containing the norbornene monomer and the reaction stock solution (ii) containing the polymerization catalyst may be mixed. Here, the reaction stock solution (ii) containing the polymerization catalyst is prepared by dissolving or dispersing the polymerization catalyst in a small amount of an inert solvent.
On the other hand, when the polymerization catalyst requires an activator, a reaction stock solution containing a norbornene monomer and a polymerization catalyst (hereinafter sometimes referred to as “solution A”), a norbornene monomer and an activator are used. What is necessary is just to mix the reaction stock solution (it may be hereafter called "B liquid") contained. At this time, a reaction stock solution consisting of only a norbornene-based monomer (hereinafter sometimes referred to as “C solution”) may be used in combination.

The filler may be incorporated into any of the above reaction stock solutions (“A solution”, “B solution” or “C solution”, or the reaction stock solution (i) or the reaction stock solution (ii)). It is preferable to mix and use in a reaction stock solution containing.
The fibrous filler and the particulate filler may be blended in separate reaction stock solutions, or both may be blended in the same reaction stock solution, but the latter blending method is preferred, thereby Sedimentation of the material is suppressed, and the storage stability of the polymerizable composition is improved.

In the method for producing a reaction injection molded article of the present invention, first, the polymerizable composition is bulk polymerized in a mold to obtain a molded article.
In order to bulk polymerize a polymerizable composition containing a norbornene monomer, a polymerization catalyst and an inorganic filler in a mold, for example, a known collision mixing device can be used as a reaction injection molding (RIM) device. .
Two or more kinds of reaction stock solutions (“A solution”, “B solution” and “C solution”, or reaction stock solution (i) and reaction stock solution (ii)) are separately introduced into the collision mixing apparatus. The reaction injection-molded article can be obtained by instantaneously mixing with a mixing head, pouring the resulting polymerizable composition into a mold, and bulk polymerization in the mold.
Note that a low-pressure injector such as a dynamic mixer or a static mixer can be used instead of the collision mixing device.
The temperature of the reaction stock solution before supply is preferably 10 to 60 ° C., and the viscosity of the reaction stock solution is usually about 5 to 3,000 cP, preferably about 50 to 1,000 cP at 30 ° C., for example.

There is no particular limitation on the mold used for reaction injection molding, but usually a mold formed of a male mold and a female mold is used.
The material of the mold is not particularly limited, and can indicate metals such as steel, aluminum, zinc alloy, nickel, copper, and chromium, and resins. In addition, these molds may be manufactured by any method such as casting, forging, thermal spraying, and electroforming, or may be plated.
The structure of the mold may be determined in consideration of the pressure when the mixed liquid and the coating agent are injected into the mold. The mold clamping pressure is gauge pressure and is usually 0.1 to 9.8 MPa.
The molding time varies depending on the types of norbornene monomer, polymerization catalyst and polymerization activator (cocatalyst), their composition ratio, mold temperature, etc., but is not uniform, but generally 5 seconds to 6 minutes. It is preferably 10 seconds to 5 minutes.

In the case where the reaction stock solution is supplied into a cavity formed by a male mold and a female mold, and bulk polymerization is performed, the male mold temperature T1 (° C.) is changed to the female mold temperature T2. It is preferable to set higher than (° C.). Thereby, the surface on which the coating film is formed in the molded body can be a beautiful surface with no surface marks or bubbles, which can contribute to improving the adhesion of the coating film.
The difference (T1−T2) between the mold temperature T1 of the male mold and the mold temperature T2 of the female mold is preferably 5 ° C. or more, more preferably 10 ° C. or more, and the upper limit is preferably 60 ° C. or less. is there. T1 is preferably 110 ° C. or lower, more preferably 95 ° C. or lower, and the lower limit is preferably 50 ° C. or higher. T2 is preferably 70 ° C. or lower, more preferably 60 ° C. or lower, and the lower limit is preferably 30 ° C. or higher.
Examples of the method for adjusting the mold temperature include adjusting the mold temperature with a heater; adjusting the temperature of a heat medium such as temperature-controlled water and oil that is circulated in a pipe embedded in the mold.

When bulk polymerization proceeds in the mold, a molded body made of norbornene resin is obtained, and a gap is formed between the mold and the molded body by molding shrinkage (hereinafter, this gap is simply referred to as “gap”). Occurs.
In the present invention, a coating film is formed on the surface of the molded body by injecting a coating material into the gap from the coating material injection port. In order to more reliably inject the coating agent, the male mold is slightly opened relative to the female mold, and a sufficient gap is provided between the inner surface of the male mold and the molded body. After forming, a coating may be injected.
In the case where a plurality of coating agent injection ports are provided, the coating agent is preferably injected from all the injection ports simultaneously. By injecting at the same time, the coating agent can be introduced without uneven injection. In addition, you may inject | pour a coating agent between the metal mold | die inner surface of a male metal mold | die and a molded object by the pressure higher than a mold clamping pressure, with a male metal mold | die and a female metal mold | die closed. What is necessary is just to determine a clearance gap suitably in consideration of the coating film thickness finally obtained.

  The composition of the coating is not particularly limited. For example, an oligomer having at least two (meth) acryloyl groups and / or an unsaturated polyester resin (vehicle component), an ethylenically unsaturated monomer (monomer component), polymerization It is preferable to use a coating composition containing an initiator, an accelerator for an organic peroxide polymerization initiator, and a release agent having a melting point of 125 ° C. or lower.

  Examples of the oligomer having at least two (meth) acryloyl groups used as a vehicle component include an epoxy (meth) acrylate oligomer, a urethane (meth) acrylate oligomer, a polyester (meth) acrylate oligomer, and a polyether (meth) acrylate oligomer. Can be mentioned.

  Epoxy (meth) acrylate oligomers are used to convert an epoxy compound and (meth) acrylic acid into a normal epoxy group in such a ratio that the carboxyl group equivalent is 0.5 to 1.5 per equivalent of epoxy group. It is produced by a cycloaddition reaction. Here, other unsaturated carboxylic acids may be used instead of (meth) acrylic acid.

The urethane (meth) acrylate oligomer can be obtained by batch mixing and reacting a diisocyanate compound, a diol compound and a hydroxy group-containing (meth) acrylate. As another method, a diol compound and a diisocyanate compound are reacted to form a urethane isocyanate intermediate containing one or more isocyanate groups per molecule, and then the intermediate and the hydroxy group-containing (meth) acrylate are combined. Method of reacting, reacting a diisocyanate compound and a hydroxy group-containing (meth) acrylate to form a urethane (meth) acrylate intermediate containing one or more isocyanate groups per molecule, and then the intermediate and the diol compound And the like.
Here, various known compounds can be used as the diisocyanate compound. Specific examples include organic diisocyanates such as tolylene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, 1,2-diisocyanatoethane, hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane. Can do. These diisocyanate compounds may be used alone or as a mixture.
Examples of the diol compound include alkylene glycol such as ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, and polypropylene glycol, and diester diol that is a diester reaction product of dicarboxylic acid or its anhydride. It is done.
Furthermore, examples of the hydroxy group-containing (meth) acrylate include, for example, the general formula: CH ₂ ═CRCO ₂ — (C _n H _2n ) —OH (where R is —H or —CH ₃ , and n is 2 to 8). Which is an integer of) is useful.

The polyester (meth) acrylate oligomer can be produced, for example, by a reaction between a polyester polyol having a hydroxyl group at the terminal and (meth) acrylic acid. Instead of (meth) acrylic acid, other unsaturated carboxylic acids may be used.
The polyether (meth) acrylate oligomer can be produced, for example, by reacting a polyether polyol such as polyethylene glycol or polypropylene glycol with (meth) acrylic acid. Instead of (meth) acrylic acid, other unsaturated carboxylic acids may be used.

  The unsaturated polyester resin used as the vehicle component can be produced, for example, by a condensation reaction between an unsaturated dibasic acid such as maleic acid or fumaric acid and a polyhydric alcohol such as ethylene glycol, propylene glycol or trimethylolpropane. .

Examples of the ethylenically unsaturated monomer used as the monomer component include styrene, α-methylstyrene, chlorostyrene, vinyltoluene, divinylbenzene, methyl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and tripropylene. Typical examples include glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, silicone (meth) acrylate, and silicone di (meth) acrylate, but are not limited thereto.
The amount of the monomer component is appropriately 20 to 200 parts by weight, preferably 40 to 160 parts by weight, based on 100 parts by weight of the vehicle component, and a coating having appropriate curing characteristics and viscosity can be obtained within this range. .

As the polymerization initiator used for the coating agent, an organic peroxide polymerization initiator is preferable.
The organic peroxide polymerization initiator is used for polymerizing the vehicle component and the monomer component. The organic peroxide polymerization initiator preferably has a 1 minute half-life temperature of 90 ° C to 135 ° C. Examples of such organic peroxides include bis (4-t-butylcyclohexyl) peroxydicarbonate, diisopropyl peroxydicarbonate, t-butylperoxyneodecanoate, and t-butylperoxyneohexanoate. Ate, t-butylperoxyneoheptanoate, t-hexylperoxyneodecanoate, t-butylperoxypivalate, lauroyl peroxide, 2,4,4-trimethylpentylperoxy-2-ethylhexanoate Typical examples include, but are not limited to, ate, t-amylperoxy-2-ethylhexanoate, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, and the like.

  Since the cured product of norbornene-based monomer is usually molded at a mold temperature of 65 to 95 ° C., when the one-minute half-life temperature of the organic peroxide polymerization initiator is higher than 135 ° C., the curing time of the coating agent Will be significantly longer and in some cases will not cure at all. On the other hand, if the half-life temperature for 1 minute is lower than 90 ° C., the pot life of the coating agent is remarkably shortened and gelation occurs in the coating agent injection apparatus, which makes it impossible to inject the coating agent. The compounding amount of the organic peroxide polymerization initiator is 0.1 to 15 parts by weight, preferably 1 to 8 parts by weight, based on 100 parts by weight of the vehicle component.

  Typical accelerators for organic peroxide polymerization initiators include cobalt naphthenate, cobalt octylate, zinc naphthenate, zinc octylate, manganese naphthenate, lead naphthenate, or mixtures thereof. However, it is not limited to these. An appropriate amount of the accelerator is 0.01 to 20 parts by weight, preferably 0.04 to 10 parts by weight per 100 parts by weight of the vehicle component.

As the release agent, a release agent having a melting point of 125 ° C. or lower is preferably used. Typical examples of such release agents include stearic acid, hydroxystearic acid, zinc stearate, soybean oil lecithin, silicone oil, fatty acid esters, and fatty acid alcohol dibasic acid esters.
Considering that the molding temperature of the norbornene monomer is usually 65 to 95 ° C. and the surface temperature of the cured product rises due to the reaction heat of the norbornene monomer when the melting point of the release agent is higher than 125 ° C. The mold release agent does not melt sufficiently and the original mold release effect is difficult to obtain. The release agent may be liquid at normal temperature.
The compounding amount of the release agent is suitably 0.1 to 15 parts by weight, preferably 0.3 to 5 parts by weight with respect to 100 parts by weight of the vehicle component, and the release effect is exhibited within this range.

For the coating agent, metal powder, mold release agent other than the above, curing accelerator, polymerization inhibitor, ultraviolet absorber, light stabilizer, colored pigment, extender pigment, conductive pigment, modified resin as necessary Further, a surface conditioner or the like can be blended.
Examples of the release agent other than the above include fluorine compounds such as silicone oil and hexafluoropropene oligomer, and wax.
Examples of the polymerization inhibitor include hydroquinone, benzoquinone, pt-butylcatechol and the like.
Typical examples of the ultraviolet absorber and the light stabilizer include benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers.
Examples of the color pigment include titanium oxide, iron oxide, phthalocyanine blue, phthalocyanine green, and carbon black.
Examples of extender pigments include calcium carbonate, talc, silica, clay, mica, barium sulfate, aluminum hydroxide, and the like.
Examples of the conductive pigment include conductive carbon black and graphite.
The modified resin needs to have good compatibility with the vehicle component, and specific examples thereof include polymethyl methacrylate, polyvinyl acetate, saturated polyester, chlorinated polyolefin, and the like.

  The viscosity of the coating agent is preferably 500 to 10,000 mPa · s as measured by a B-type viscometer at 30 ° C. (rotor # 2, 30 rpm) from the viewpoint of suppressing the wraparound of the coating agent and the generation of bubbles, 600 ˜7,000 mPa · s is more preferred, and 700 to 6,000 mPa · s is particularly preferred.

The timing of injecting the coating agent from the coating agent injection port is such that after injecting each component of the polymerizable composition such as a norbornene monomer into the mold, a bulk polymerization reaction occurs inside the mold, and the temperature of the molded body is increased. From the time of reaching the maximum temperature, it is preferably within 5 seconds to 20 minutes, more preferably within 5 seconds to 10 minutes, and particularly preferably within 10 seconds to 5 minutes. When the timing of injecting the coating agent is too early, the reaction of the reaction solution of the molding material is insufficient and there is a risk of deformation due to the injection pressure of the coating agent. On the other hand, if the timing of injecting the coating agent is too late, the difference between the place where the shrinkage of the molded body becomes large and the place where the shrinkage does not become large becomes remarkable, and the coating spot becomes large and the aesthetic appearance may be remarkably lowered.
The mold temperature of the male mold at the time of injecting the coating agent into the gap may be lower than the curing temperature of the coating agent, but it is preferable to set it above the curing temperature of the coating agent after the injection of the coating agent. .
The injection pressure of the coating agent is not particularly limited, but is preferably 1 to 50 MPa, more preferably 3 to 30 MPa, and particularly preferably 5 to 22 MPa. If the pressure is too low, the coating agent may not penetrate sufficiently. Conversely, if the injection pressure is too high, the equipment cost will be excessive and the mold structure will need to be pressure resistant, resulting in poor economics. there is a possibility.

  After injecting the coating agent, the coating agent is cured by being held at a predetermined temperature for a predetermined time. The curing temperature of the coating agent is preferably 70 to 110 ° C., more preferably 80 to 100 ° C., and the curing time is preferably 20 seconds to 6 minutes, more preferably 60 seconds to 4 minutes. If the curing temperature is too high, the coating agent and the surface of the molded product may not be sufficiently adhered, and the coating agent may peel off. In addition to not being able to inject the agent to every corner, the injection pressure may become higher and the injector and mold may be damaged. If the curing time is too short, the coating agent may be insufficiently cured and the coating may be peeled off. Conversely, if the curing time is too long, the productivity may be reduced.

After the coating agent is cured, the mold is completely opened and demolded to form a molded body on which the coating film of the present invention is formed. More specifically, a bonnet molded body or a large panel (basin) In some cases, it may be a shaped product).
The reaction injection molded body of the present invention is suitably used as a large panel (particularly a basin-shaped molded body) such as a concrete panel serving as a guide when pouring concrete; an outer wall panel for storing water or storing water-soluble chemicals, and the like. The length of the long side of the large panel (longest side in the case of a basin-shaped body) is preferably 1,000 mm to 3,000 mm, and the length of the short side (shortest side in the case of a basin-shaped body). The thickness is preferably 400 to 2,000 mm.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In the following, “parts” and “%” are based on weight unless otherwise specified.

[Example 1]
(Mold)
Gold consisting of a forged aluminum female mold and an electroformed aluminum male mold for forming a bonnet-shaped body having an upper end of 1,200 mm in length and 600 mm in width and a lower end of 1,190 mm in length, 590 mm in width and 150 mm in height The male mold has a coating agent injection port at three locations on the center and apex of both longitudinal sides, and an injector having a maximum injection pressure of 40 MPa was attached to each coating agent injection port. A guide and a weir for forming a burr having a width of 30 mm and a thickness of 0.5 mm are formed around the basin-shaped molded body and the runner part on the upper outer periphery of the female mold, and two sides orthogonal to the male burr terminal Grooves for forming a coating leakage preventing projection having a right-angled triangular cross-section each having a length of 5 mm were provided. The groove was formed so that the vertical portion of the coating leakage preventing projection faced the molded body side. Further, a putty having a length of about 10 mm was buried in one portion of the male groove as a projection defect for discharging air.

(Reaction stock solution and coating agent)
As a reaction stock solution component for reaction injection molding, a mixed monomer composed of 90 parts of dicyclopentadiene and 10 parts of tricyclopentadiene is used, and a styrene-isoprene-styrene block copolymer (manufactured by Nippon Zeon Co., Ltd., trade name “Quintac 3421”) 3) was dissolved. Next, diethylaluminum chloride as an activator and 1,3-dichloro-2-propanol as an activity regulator are added and mixed and dispersed to a concentration of 100 mmol / kg to obtain a reaction stock solution (solution A). It was. The specific gravity of A liquid was 0.98.
Separately, a styrene-isoprene-styrene block copolymer (trade name “Quintac 3421” manufactured by Nippon Zeon Co., Ltd.) is used as an elastomer in a mixed monomer composed of 90 parts of dicyclopentadiene and 10 parts of tricyclopentadiene. A part was dissolved. Next, a phenolic antioxidant (thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by Ciba Specialty Chemicals, trade name “Irganox 1010”) is used here. 2 parts dissolved, and further added tri (dodecyl) ammonium molybdate as a polymerization catalyst to a concentration of 25 mmol / kg and hexachloro-p-xylene as a polymerization accelerator to a concentration of 8.5 mmol / kg. And mixed and dispersed uniformly.
Wollastonite with a 50% volume cumulative diameter of 20 μm and an aspect ratio of 18 (trade name “SH-400, manufactured by Kinsei Matec Co., Ltd.), which is surface-treated with vinylsilane as a fibrous filler, is added to the obtained mixed liquid. ”) 42.75 parts by weight and heavy calcium carbonate with a 50% volume cumulative diameter of 1.4 μm and an aspect ratio of 1 treated with stearic acid as a particulate filler (manufactured by Sankyo Seimitsu Co., Ltd.) , 14.25 parts by weight of a product name “SCP-E # 2300”) was added and stirred and mixed to obtain a reaction stock solution (solution B). The specific gravity of the obtained B liquid was 1.46.

(Forming and forming coating film)
The male mold and the female mold are clamped, the female mold and the male mold are heated to 40 ° C. and 90 ° C., respectively, and clamped at a pressure of 0.49 MPa per area of the molded body, using a RIM molding machine, In a mixing head, 100 parts of equal volume A liquid and 146 parts B liquid were collided and mixed, and the resulting reaction stock solution was poured into the mold. After filling the reaction stock solution, the mold temperature was maintained for about 1 minute.
Next, 200 mL of the coating agent was injected into the mold at a pressure of 20 MPa and held at the mold temperature for 3 minutes. As a coating agent, 100 parts of a paint mainly composed of urethane acrylate oligomer (trade name “Praglas # 400” manufactured by Dainippon Paint Co., Ltd.), 1 part of dibutyl phthalate and bis- (4-t-butylcyclohexyl) peroxy A paste prepared by mixing 1 part of dicarbonate [trade name “Parkadox 16” manufactured by Kayaku Akzo Co., Ltd.] was used.
Thereafter, the mold was opened, and a bonnet-shaped body having a coating film was taken out. When the appearance of the design of the basin-shaped compact was visually observed, the coating state of the coating film was entirely free of defects on the entire inner surface and was covered at all portions with a thickness of 100 to 300 μm. Moreover, the total filler content of the molded body resin portion was 30%.

[Comparative Example 1]
A basin-shaped compact was obtained in the same manner as in Example 1 except that neither the fibrous filler nor the particulate filler was added. As a result of visual observation of the appearance of the design of the basin-shaped product, there was a linear non-coating portion in the concave portion of the basin-shaped product, and a coating film could not be formed on the entire basin-shaped product.

[Comparative Example 2]
A reaction stock solution (liquid B) was obtained in the same manner as in Example 1 except that the amount of the fibrous filler was 57 parts by weight and the particulate filler was not added. The specific gravity of the obtained B liquid was 1.46. Molding and formation of the coating film were performed in the same manner as in Example 1. When the design appearance of the obtained bonnet-shaped body was visually observed, the corner portions of the basin-shaped body were not painted. Moreover, the total filler content of the molded body resin portion was 30%.

[Example 2]
Covered at one central part of a forged aluminum male mold and female mold made of a forged aluminum male mold and a female mold for forming a thin box-shaped concrete panel of 1,500 mm in length, 1,300 mm in width and 100 mm in height An injector having a maximum injection pressure of 40 MPa for injecting the agent was attached. Guides and weirs for forming burrs with a width of 30 mm and a thickness of 0.5 mm around the molded body and the runner part are formed on the outer periphery of the upper part of the female mold, and the two orthogonal sides are 5 mm in length. A groove for forming a coating leakage preventing projection having a triangular cross section was provided at the burr end of the male mold. The groove was formed so that the vertical portion of the coating leakage preventing projection faced the molded body side. Further, a putty having a length of about 10 mm was buried in one portion of the male mold groove as a protrusion defect portion for air discharge.
The male mold and female mold are clamped, the male mold and female mold are heated to 40 ° C. and 90 ° C., respectively, and clamped at a pressure of 0.49 MPa per area of the molded body, and a RIM molding machine is used. Then, 400 parts of an equal volume of A liquid (same as in Example 1) and 584 parts of B liquid (same as in Example 1) are collided and mixed in the mixing head, and the resulting reaction stock solution is mixed with the above mold. And held at the mold temperature for about 1 minute.
Next, 800 mL of the same coating agent used in Example 1 was poured into the mold at a pressure of 20 MPa, and the mold temperature was maintained for 3 minutes.
Thereafter, the mold was opened, and a bonnet-shaped body having a coating film was taken out. When the appearance of the design of the basin-shaped compact was visually observed, the coating state of the coating film was entirely free of defects on the entire inner surface and was covered at all portions with a thickness of 100 to 300 μm. Moreover, the total filler content of the molded body resin portion was 30%.

From the results of the examples and comparative examples, the following can be understood.
That is, a polymerizable composition comprising a norbornene monomer, a polymerization catalyst, an inorganic filler comprising a fibrous filler having an aspect ratio of 5 to 100 and a particulate filler having an aspect ratio of 1 to 2, In the mold, a molded body is obtained, and then a coating film is formed on the surface of the molded body by an in-mold coating method in the mold, thereby obtaining a coating film having no defects on the entire coated surface. I understand. On the other hand, when only the fibrous filler is used, a non-painted portion is generated at the corner portion of the basin-shaped molded body (Comparative Example 2), and when no filler is used, the basin-shaped molding is performed. It can be seen that a coating defect occurs in the concave portion of the body (Comparative Example 1).

Claims (10)

  A polymerizable composition comprising a norbornene-based monomer, a polymerization catalyst, and an inorganic filler composed of a fibrous filler having an aspect ratio of 5 to 100 and a particulate filler having an aspect ratio of 1 to 2, A method for producing a reaction injection molded article having a coating film on its surface, characterized in that a molded article is obtained by bulk polymerization and subsequently forming a coating film on the surface of the molded article by an in-mold coating method in a mold .   The method for producing a reaction injection molded article according to claim 1, wherein the polymerizable composition is a metathesis polymerizable composition.   The content weight ratio (fibrous filler / particulate filler) between the fibrous filler and the particulate filler is 95/5 to 55/45, according to claim 1 or 2. A method for producing a reaction injection molded article.   The method for producing a reaction injection molded article according to any one of claims 1 to 3, wherein the fibrous filler has a 50% volume cumulative diameter of 0.1 to 50 µm.   The method for producing a reaction injection molded article according to any one of claims 1 to 4, wherein the particulate filler has a 50% volume cumulative diameter of 0.1 to 50 µm.   The method for producing a reaction injection molded article according to any one of claims 1 to 5, wherein the fibrous filler having an aspect ratio of 5 to 100 is wollastonite or whisker-like calcium carbonate.   The method for producing a reaction injection molded article according to any one of claims 1 to 6, wherein the particulate filler having an aspect ratio of 1 to 2 is calcium carbonate or calcium hydroxide.   The reaction injection molded article according to any one of claims 1 to 7, wherein the amount of the inorganic filler is 5 to 55 parts by weight with respect to 100 parts by weight of the total amount of the norbornene monomer and the catalyst. Manufacturing method.   A bulk polymer of norbornene-based monomers containing an inorganic filler, obtained by the method for producing a reaction injection molded article according to any one of claims 1 to 8, comprising A reaction injection molded article having a coating film.   A reaction injection molded article having a coating film according to claim 9, which is a large panel.