JP2009029865A - Blending liquid for reaction injection molding, method for producing reaction injection-molded article, and reaction injection-molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blending liquid for reaction injection molding, which is the blended liquid for performing the bulk polymerization of a norbornene-based monomer in a mold and then reaction injection molding, without reducing flowability at a low temperature and capable of obtaining an article having less surface sink. <P>SOLUTION: This blending liquid for performing the bulk polymerization of the norbornene-based monomer in the mold and then reaction injection molding is characterized by containing the norbornene-based monomer, an olefin-based elastomer having ≥60 wt.% propylene unit content and an aromatic hydrocarbon resin. The method for producing the reaction injection-molded article by using the blended liquid and the reaction injection-molded article produced by the above production method are also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reaction injection molding compounded liquid, a method for producing a reaction injection molded article using the same, and a reaction injection molded article obtained by this production method. More specifically, a norbornene-based monomer-containing reaction injection molding compound liquid containing a specific compound and exhibiting excellent fluidity even at low temperatures, a method for producing a reaction injection molded article using the same, and a method for producing the same The present invention relates to a reaction injection molded article obtained.

A norbornene-based polymer can be obtained by ring-opening polymerization of norbornene-based monomers such as norbornene, dicyclopentadiene, tetracyclododecene, etc. in a mold using a metathesis polymerization catalyst by a reaction injection molding method. It is well known.
The norbornene-based polymer thus obtained is excellent in mechanical strength, heat resistance and dimensional stability, and the molded product is a member of an automobile, agricultural equipment, construction equipment, etc., electrical equipment, electronic equipment, etc. It is used in award for housings.
Of these molded products, impact resistance is important for particularly large-sized products. In order to improve impact resistance, a method is known in which polymerization of a norbornene monomer is performed in the presence of an elastomer.
Elastomers include styrene / butadiene rubber (SBR), butadiene / styrene block copolymer (SBS), butadiene / isoprene block copolymer (SIS), poly-cis-1,4-butadiene (BR), poly-cis. -1,4-isoprene (IR), hydrogenated styrene / ethylene / butadiene block copolymer (SEBS), natural rubber, polyisobutylene rubber, ethylene / propylene rubber (EPR), ethylene / propylene / diene terpolymer Rubber (EPDM or EPT), butyl rubber (IIR) and the like are known.

  Among the above-mentioned elastomers, general-purpose olefin elastomers such as ethylene / propylene rubber and ethylene / propylene / diene-terpolymer rubber are preferably used because they have a large effect of improving impact resistance and are inexpensive. Among these general-purpose olefin elastomers, those usually used are those having an ethylene content of 50 to 90 mol%, particularly 60 to 85 mol% (Patent Document 1).

JP-A-1-204924

By the way, in the reaction injection molding of norbornene-based monomers and the like, the shrinkage of the monomer component occurs at the time of molding. This is because the resin hardened on the cavity side surface of the mold and the resin hardened on the core side surface contract together, so that the resin is pulled in the thickness direction of the resin, and the resin on the slow curing side becomes the resin on the other side. It is thought to be attracted.
In order to prevent the occurrence of this sink, various methods such as mold temperature control, resin coating on the mold surface, increase in injection pressure, adjustment of raw material supply amount, resin temperature adjustment, mold rotation, etc. have been proposed. However, sufficient effect is not obtained.

The present inventor, first, in the reaction injection molding by bulk polymerization of norbornene monomer in the mold, by adding an elastomer having a specific shear rate coefficient to the compounded liquid, Further, the fluidity of the blended liquid can be improved, and the elastomer is preferably an olefin-based elastomer, having a propylene unit of 50 to 95% by weight, an ethylene unit of 5 to 50% by weight and a diene monomer unit. It has been found that a composition consisting of 0 to 10% by weight is particularly suitable (Japanese Patent Application No. 2006-352047).
However, it has been found that the liquid mixture containing such an elastomer has a problem that fluidity at a low temperature is lowered, and in a severe case, the liquid is frozen. This fluidity is recovered when the temperature is increased. However, in operation in a cold region, for example, an apparatus / operation for maintaining such a mixed solution at a certain temperature or more is required, which is not economical.

Accordingly, an object of the present invention is a compounded liquid for reaction injection molding by bulk polymerization of norbornene-based monomers in a mold, and a molded product with less sink marks can be obtained without lowering fluidity even at low temperatures. It is in providing the compounding liquid for reaction injection molding.
Another object of the present invention is to provide a method for producing a reaction injection molded article using the above blended solution.
Still another object of the present invention is to provide a molded article obtained by this production method.

  In order to achieve the above-mentioned object, the present inventor has intensively studied the composition of the reaction injection molding liquid composition. As a result, by adding a specific compound to the liquid mixture, the fluidity of the liquid mixture can be lowered at a low temperature. It was found that the reaction injection molded article can be prevented from sinking, and the present invention has been completed based on this finding.

Thus, according to the present invention, there is provided a compounded liquid for reaction injection molding by bulk polymerization of norbornene-based monomers in a mold, the norbornene-based monomer, an olefinic elastomer having a propylene unit content of 60% by weight or more, and an aromatic There is provided a reaction injection molding compounded liquid characterized in that it contains a series hydrocarbon resin.
In the compounding liquid for reaction injection molding of the present invention, the olefin elastomer is preferably composed of 60 to 95% by weight of propylene units, 5 to 40% by weight of ethylene units and 0 to 5% by weight of nonconjugated diene monomer units. .
In the compounding liquid for reaction injection molding of the present invention, the blending amount of the olefin elastomer is preferably 1 to 20 parts by weight per 100 parts by weight of the norbornene monomer.
In the reaction injection molding liquid according to the present invention, the amount of the aromatic hydrocarbon resin is preferably 1 to 20 parts by weight per 100 parts by weight of the norbornene monomer.

Moreover, according to this invention, the manufacturing method of the reaction injection molding body which carries out the block polymerization of the compounding liquid for reaction injection molding of this invention in a mold, and performs reaction injection molding is provided.
Furthermore, according to this invention, the reaction injection molded object obtained by the manufacturing method of the reaction injection molded object of this invention is provided.

The liquid mixture for reaction injection molding of the present invention does not decrease in fluidity even at low temperatures. Therefore, it is economical because it does not require any equipment or operation for keeping warm even in cold regions.
Moreover, even if it is large sized, the molded object with few sink marks can be obtained using the reaction injection molding compounded liquid of this invention.
The reaction injection molded product obtained in the present invention is used in 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, medical applications such as medical equipment, It can be suitably used in industrial applications such as large panels and chairs, and residential equipment applications such as shower pans and wash bowls.

  The reaction injection molding compounded liquid of the present invention (hereinafter sometimes simply referred to as “compounded liquid”) is a compounded liquid for reaction injection molding by bulk polymerization of norbornene monomers in a mold, It contains a monomer, an olefin elastomer having an propylene unit content of 60% by weight or more, and an aromatic hydrocarbon resin.

  The norbornene-based monomer used in the present invention is not particularly limited as long as it is a compound having a norbornene ring structure.

Norbornene-based monomers include norbornene, norbornadiene and other bicyclics; dicyclopentadiene (cyclopentadiene dimer), dihydrodicyclopentadiene and other tricyclics; tetracyclododecene and other tetracyclics; cyclopentadiene trimer And pentacycles such as cyclopentadiene tetramers and the like.
These norbornene monomers include an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group; an alkenyl group such as a vinyl group; an alkylidene group such as an ethylidene group; an aryl group such as a phenyl group, a tolyl group, and a naphthyl group; And the like.
Further, these norbornene monomers may have a polar group such as a carboxy group, an alkoxycarbonyl group, an acyloxy group, an oxy group, a cyano group, or a halogen atom.

  Specific examples of the norbornene-based monomer include dicyclopentadiene, tricyclopentadiene, cyclopentadiene-methylcyclopentadiene codimer, 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-hexahydrona Array type, ethylene bis (5-norbornene), and the like.

Norbornene monomers may be used alone or in combination of two or more.
Of the norbornene monomers, tricyclic, tetracyclic or pentacyclic norbornene monomers are preferred because they are easily available, have excellent reactivity, and have excellent heat resistance of the resulting molded article.

  In addition, it is preferable that the ring-opening polymer to be produced is a thermosetting type. For this purpose, among the norbornene-based monomers, two or more reactive double bonds such as a symmetric cyclopentadiene trimer are used. Those containing at least a crosslinkable monomer are used. The ratio of the crosslinkable monomer in all norbornene monomers is preferably 2 to 30% by weight.

  In addition, monocyclic cycloolefins such as cyclobutene, cyclopentene, cyclopentadiene, cyclooctene, and cyclododecene that can be ring-opening copolymerized with a norbornene-based monomer may be used as a comonomer within a range that does not impair the object of the present invention.

It is essential that the blended liquid of the present invention contains an olefin elastomer having a propylene unit content of 60% by weight or more.
As the olefin elastomer, ethylene / propylene copolymer (EPR) and ethylene / propylene / nonconjugated diene-terpolymer (EPDM) are preferable.
These olefin-based elastomers may contain an α-olefin having about 4 to 8 carbon atoms as a constituent element in addition to ethylene, propylene, and non-conjugated diene.
In these olefin elastomers, the propylene unit content needs to be 60% by weight or more. Even if an olefin-based elastomer having a propylene unit content of less than 60% by weight is used, the effect of preventing the fluidity of the compounded liquid from being lowered cannot be obtained.

The ethylene-propylene copolymer is preferably composed of 60 to 95% by weight of propylene units and 5 to 40% by weight of ethylene units, and is composed of 65 to 93% by weight of propylene units and 7 to 35% by weight of ethylene units. It is more preferable that it is composed of 70 to 90% by weight of propylene units and 10 to 30% by weight of ethylene units.
The ethylene-propylene-nonconjugated diene terpolymer (EPDM) is preferably composed of 65 to 93% by weight of propylene units, 7 to 35% by weight of ethylene units and 10% by weight or less of nonconjugated diene monomer units. More preferably, it is composed of 70 to 90% by weight of propylene units, 4 to 29% by weight of ethylene units and 1 to 6% by weight of non-conjugated diene monomer units.
Here, as the non-conjugated diene monomer, ethylidene norbornene, dicyclopentadiene or the like is usually used.

  The olefin elastomer used in the present invention preferably has a melt flow rate (230 ° C., load 2.16 kg) of 1 to 20 g / 10 min.

The olefin elastomer used in the present invention preferably has a shear rate coefficient of 1.30 or more and 1.60 or less. The shear rate coefficient is more preferably in the range of 1.50 to 1.60.
When the shear rate coefficient of the olefin-based elastomer is within the above range, the compounded liquid is particularly excellent in fluidity, and using this, it becomes easy to obtain a molded product with less sink marks.

Here, the shear rate coefficient is a numerical value obtained as follows.
That is, the monomer / elastomer mixture obtained by adding an amount of elastomer so that the viscosity of the obtained monomer / elastomer mixture at 30 ° C. to 320 mPa · s is added to the monomer to be blended with the elastomer is maintained at 30 ° C. 1 and using a piston having a cylindrical die having a nozzle radius (r) of 0.95 mm and a height of 9.3 mm at the lower end as shown in FIG. 1 and extruding at an extrusion pressure of 10.2 kPa. The liquid amount (q) is obtained, and the shear rate A is obtained from this effluent amount according to the equation (1).
Similarly, the shear rate B when the extrusion pressure is 33.2 kPa is obtained.
From these shear rates A and B, the shear rate coefficient is determined according to the equation (2).
Shear rate (1 / s) = 4q / πr ³ ρ (1)
(In the formula (1), q is the amount (g / s) of the monomer / elastomer mixture flowing out from the die per unit time, r is the radius (cm) of the die nozzle, and ρ is the monomer / elastomer mixture. Density (g / cm ³ ).
Shear rate coefficient = ln (shear rate B / shear rate A) / ln (33.2 / 10.2) (2)

In the present invention, the olefin elastomer preferably has a Mooney viscosity of 5 or more and 100 or less.
When the Mooney viscosity of the olefin-based elastomer is higher than the above range, the molecular chain of the olefin-based elastomer may be cut while the compounded liquid is circulated through the reaction injection molding machine, and the physical properties of the obtained molded product may be deteriorated. Moreover, when Mooney viscosity is lower than the said range, there exists a possibility that an olefin type elastomer may be completely compatible with a molded article and impact resistance may be inferior.

In the blended liquid of the present invention, the blend amount of the olefin elastomer is preferably 1 to 20 parts by weight, more preferably 1.5 to 15 parts by weight per 100 parts by weight of the norbornene monomer. Particularly preferred is 10 parts by weight.
When the blending amount is within the above range, a molded product with good fluidity of the blending solution and less sink marks can be obtained.

In the compounded liquid of the present invention, other elastomers can be used in combination with the olefin-based elastomer.
Specific examples of elastomers that can be used in combination include natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer (SBR), styrene-butadiene-styrene block copolymer (SBS), and styrene-isoprene-styrene copolymer. Examples thereof include coalescence (SIS), ethylene-vinyl acetate copolymer (EVA), and hydrides thereof.

It is essential that the blended liquid of the present invention contains an aromatic hydrocarbon resin.
Here, the aromatic hydrocarbon resin is a homopolymer or copolymer of an aromatic vinyl compound and a copolymer of an aromatic vinyl compound and a monomer copolymerizable therewith. The aromatic hydrocarbon resin may be one obtained by hydrogenating a carbon-carbon unsaturated bond contained therein after polymerization.

  Specific examples of the aromatic vinyl compound include styrene compounds such as styrene, vinyl toluene, α-methylstyrene, α-methyl-p-methylstyrene, ethylstyrene, isobutylstyrene, t-butylstyrene, bromostyrene, and chlorostyrene; In the present invention, indene compounds such as indene and methylindene and coumarone compounds such as coumarone and its derivatives; in addition to these, dimers of any combination of these styrene compounds, indene compounds and coumarone compounds Are also included in the aromatic vinyl compounds.

  The monomer copolymerizable with the aromatic vinyl compound includes (meth) acrylic acid; (meth) methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate. Α, β-ethylenically unsaturated nitriles such as (meth) acrylonitrile; α, β-ethylenically unsaturated groups such as itaconic acid, maleic acid, fumaric acid, crotonic acid and cinnamic acid Carboxylic acid; N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-octylmaleimide, N-isopropylmaleimide, N-phenylmaleimide, Np-bromophenylmaleimide, N-o-chlorophenylmaleimide, N -Maleimides such as cyclohexylmaleimide; α, β such as maleic anhydride and itaconic anhydride Ethylenically unsaturated carboxylic acid anhydride; epoxy group-containing α, β-ethylenically unsaturated compound such as allyl glycidyl ether; α, β-ethylenically unsaturated amine such as allylamine; α, β-ethylenically unsaturated such as acrylamide Saturated amides; and the like.

  In the present invention, as the aromatic hydrocarbon resin, a styrene resin and a hydride thereof, a C9 hydrocarbon resin and a hydride thereof are preferable, and among them, a C9 hydrocarbon resin and a hydride thereof are preferable.

  Styrene resins are homopolymers and copolymers of the above styrene compounds, which are rubber-reinforced styrene resins obtained by polymerizing styrene compounds in the presence of rubber components such as styrene / butadiene rubber and polybutadiene. Also good. The number average molecular weight of the styrene resin is not particularly limited, but is usually preferably about 100,000 to 600,000, more preferably about 150,000 to 500,000.

The C9 hydrocarbon resin is a resin obtained by cationic polymerization of a polymerizable monomer contained in a C9 fraction obtained by cracking naphtha.
Among them, a C9 fraction obtained by naphtha cracking (consisting of about 40% by weight of vinyl toluene, about 40% by weight of indene compound, about 20% by weight of styrene, and other α-methylstyrene) is distilled to obtain a C9 fraction. The indene compound and the high boiling point compound are removed, and the vinyl toluene content in the polymerizable monomer is 50% by weight or more, preferably 55% by weight or more, more preferably 60% by weight or more, and the indene content is 20% by weight. % Or less, preferably 15% by weight or less, more preferably 10% by weight or less is preferable.
Further, the hydride of the C9-based hydrocarbon resin is preferably a hydrogenated 5-100%, more preferably 10-98% of the aromatic ring.

Hydrogenation of such a C9 hydrocarbon resin is carried out by polymerizing a C9 fraction containing a polymerizable monomer having the above specific composition by a known cationic polymerization method to produce a C9 hydrocarbon resin, This is carried out by hydrogenation with a catalyst.
As the hydrogenation catalyst, metals such as nickel, palladium, platinum, cobalt, rhodium, ruthenium and molybdenum or metal compounds such as oxides and sulfides thereof can be used.
These hydrogenation catalysts may be used by being supported on a carrier such as porous, large surface area alumina, silica, diatomaceous earth, carbon, titania and the like. Among these catalysts, it is preferable to use a nickel-diatomaceous earth catalyst from the viewpoint of cost. The catalyst is used in an amount of about 0.1 to 20% by weight, preferably 0.1 to 3% by weight, based on the C9 hydrocarbon resin as a raw material.
The conditions for the hydrogenation reaction are not particularly limited, and the hydrogen pressure is usually about 10 to 300 kg / cm ² , more preferably 30 to 200 kg / cm ² . The reaction temperature is usually about 150 to 330 ° C, more preferably 200 to 310 ° C.

70-180 degreeC is preferable and, as for the softening point of C9 type hydrocarbon resin and its hydride used in this invention, 100-160 degreeC is more preferable. If the softening point is too high, there may be a problem that impact resistance is lowered. On the other hand, when the softening point is too low, there is a risk that the heat resistance is deteriorated.
Further, the molecular weight of the C9 hydrocarbon resin is not particularly limited, but generally a number average molecular weight of about 500 to 10,000 is preferable.

In the blended liquid of the present invention, the blend amount of the aromatic hydrocarbon resin is preferably 1 to 20 parts by weight, more preferably 5 to 15 parts by weight, per 100 parts by weight of the norbornene monomer.
If the blending amount of the aromatic hydrocarbon resin is too small, the fluidity at low temperatures may be lowered. On the other hand, if the blending amount is too large, not only is it not economical, but there is a possibility that a problem that the physical properties of the obtained reaction injection molded product are deteriorated may occur.

It is preferable that the compounded liquid of the present invention further contains a polymerization catalyst.
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 chloroxide; 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, an oxy organic tungsten halide and organic ammonium molybdate are preferable. When these metathesis polymerization catalysts are used, it is preferable to use an activator (cocatalyst) in combination for the purpose of controlling the polymerization activity.

As a metathesis polymerization catalyst, it is also preferable to use a metal carbene complex having a metal atom of Groups 5, 6 and 8 as a central metal. 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 ruthenium carbene complex has excellent catalytic activity during bulk polymerization, so it is excellent in productivity of norbornene-based resin molded products, and the resulting norbornene-based resin molded products have less odor derived from unreacted norbornene-based monomers. .
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 too intense, so it will cure before being fully filled in the mold. Or the catalyst is likely to be deposited, and it is difficult to store it homogeneously.

Further, when the metathesis polymerization catalyst requires an activator, the compounding solution may contain this activator.
In this case, the activator is not added to the compounded solution containing the metathesis polymerization catalyst, but is a separate compounded solution containing the norbornene monomer, the olefin elastomer, the aromatic hydrocarbon resin, and the activator. Is preferred.
The activator 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 organozinc compounds such as diethylzinc. 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, if the amount used is too large, the reaction is so intense that it may harden before it is fully 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.

When the polymerization catalyst requires an activator, it is preferable to use an activity regulator in combination. As will be described later, the activity regulator is prepared by mixing a compounding solution containing a polymerization catalyst and a compounding solution containing an activator and injecting the mixture into a mold to start the polymerization. It is for prevention.
As such an activity regulator, Lewis bases such as ethers, esters and nitriles; acetylenes; and α-olefins are preferably used. Specifically, examples of the Lewis base include butyl ether, ethyl benzoate, diglyme and the like. Examples of acetylenes include phenylacetylene, and examples of the α-olefin include vinyl norbornene. Further, 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 the compounded solution containing the activator. 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 2,4-dichlorobenzotrichloride, hexachloro-p-xylene, 2,4-dichloro-trichlorotoluene and silicon tetrachloride.
The addition amount of the activity regulator and the polymerization accelerator is not particularly limited, but the polymerizable composition (the compounded liquid of the present invention at the time of reaction injection molding, which is a norbornene monomer, an olefin elastomer, an aromatic hydrocarbon In addition to a resin and a polymerization catalyst, it contains a necessary component such as an activator.) It is approximately 10 ppm to 10% of the weight.

In this invention, a filler can be mix | blended as an arbitrary component of a mixing | blending liquid.
The filler may be an inorganic filler or an organic filler, but an inorganic filler is preferred.
The inorganic filler may be a fibrous filler having an aspect ratio of 5 to 100 or a particulate filler having an aspect ratio of 1 to 2. 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.

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.

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.

The content weight ratio (fibrous filler / particulate filler) of the fibrous filler and the particulate filler is preferably 95/5 to 55/45, and preferably 80/20 to 60/40. Is more preferable.
When this ratio is within the above range, it becomes easier to obtain a molded article having excellent rigidity and dimensional stability.

It is preferable that the surface of the filler is hydrophobized. By using the hydrophobized filler, it is possible to prevent the filler from aggregating and settling in the blended liquid, and to make the filler dispersed uniformly in the resulting molded body. The rigidity and dimensional stability can be made uniform, and further, 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.
Hydrophobic treatment of the filler can also be done by mixing the hydrophobizing agent at the same time when preparing a compounded liquid containing norbornene monomer, olefin elastomer, aromatic hydrocarbon resin and filler. However, it is preferable to prepare the compounded liquid using a filler that has been previously hydrophobized.

The amount of the 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 filler is too large, it may settle in the tank or piping when the compounded liquid 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 this invention, you may mix | blend various additives with a compounding liquid in order to improve or maintain the characteristic of a molded object. 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, dicyclopentadiene-based thermal polymerization resins and hydrogenated products thereof.

  Various additives are used by adding them to a compounded solution containing a polymerization catalyst and an activator; separately prepared as a monomer solution and mixed with a compounded solution containing a catalyst and an activator during reaction injection molding; And the like. What is necessary is just to select suitably the addition method with the kind of additive.

  In the present invention, the method for preparing a blended liquid containing each component such as a polymerization catalyst and an activator in addition to the norbornene-based monomer, the olefin-based elastomer, and the aromatic hydrocarbon resin is particularly limited. Instead, these components may be mixed by any method.

In the method for producing a reaction injection molded article of the present invention, the polymerizable composition obtained by mixing the above-mentioned blended liquids is bulk polymerized in a mold to obtain a molded article.
Although the preparation method of a polymeric composition is not specifically limited, Typically, the following two methods can be shown by whether a polymerization catalyst requires an activator.
That is, when the polymerization catalyst does not require an activator, the compounded liquid (i) containing the norbornene monomer, the olefin elastomer and the aromatic hydrocarbon resin, and the polymerization catalyst dissolved in a small amount of an inert solvent or What is necessary is just to mix the liquid mixture (ii) prepared by disperse | distributing. If necessary, the olefin elastomer and the aromatic hydrocarbon resin may be contained in the compounded liquid (ii).

On the other hand, when the polymerization catalyst requires an activator, a blended liquid containing a norbornene monomer and a polymerization catalyst (hereinafter sometimes referred to as “A liquid”), a norbornene monomer and an activator are used. What is necessary is just to mix the compounded liquid to contain (henceforth "B liquid"). At this time, you may use together the liquid mixture (henceforth "C liquid") consisting only of a norbornene-type monomer.
In this case, the olefin elastomer and the aromatic hydrocarbon resin may be blended in any of the above blended liquids, but the olefin elastomer and the aromatic hydrocarbon resin are blended in the same blended liquid. . That is, for example, when an olefin elastomer is blended in the liquid A, an aromatic hydrocarbon resin is also blended in the liquid A.

  When the filler is used, the filler may be blended in any of the above-described blending liquids (A liquid, B liquid or C liquid, or the blending liquid (i) or the blending liquid (ii)). It is preferable to mix and use in (i) or C liquid.

In order to bulk polymerize a polymerizable composition containing a norbornene monomer, an olefin elastomer, an aromatic hydrocarbon resin, a polymerization catalyst, and other necessary components such as an activator in a mold, for example, reaction injection A known collision mixing device can be used as a molding (RIM) device.
Two or more kinds of liquid mixture (A liquid, B liquid and C liquid, or liquid mixture (i) and liquid mixture (ii)) are separately introduced into the collision mixing apparatus, and instantaneously mixed with a mixing head. The reaction injection-molded article can be obtained by injecting the polymerizable composition obtained into the mold and injecting the polymerizable composition into a mold and performing 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 blended solution before being subjected to reaction injection molding is preferably 10 to 60 ° C., and the viscosity is usually 5 to 3,000 mPa · s, preferably 50 to 1,000 mPa · s, for example, at 30 ° C. It is about s.

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 polymerizable composition is injected into the mold. The mold clamping pressure is 0.1 to 9.8 MPa in gauge pressure.
The molding time varies depending on the types of norbornene-based monomer, polymerization catalyst and activator, their composition ratio, mold temperature, etc., but is not uniform, but generally 5 seconds to 6 minutes, preferably 10 seconds. ~ 5 minutes.

When a polymerizable composition is supplied into a cavity formed by a male mold and a female mold as a pair and bulk polymerization is performed, the mold temperature T1 (° C.) of the design surface side mold is generally set to the design surface. It is preferable to set it higher than the mold temperature T2 (° C.) of the mold on the corresponding side. Thereby, the surface appearance of a molded object can be made beautiful without sinks or bubbles.
T1-T2 has a lower limit of preferably 5 ° C or higher, more preferably 10 ° C or higher, and an upper limit of preferably 60 ° C or lower. The upper limit of T1 is preferably 110 ° C. or lower, more preferably 95 ° C. or lower, and the lower limit is preferably 50 ° C. or higher. The upper limit of 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 adjustment of the mold temperature using a heater; temperature adjustment of temperature-controlled water to be circulated in a pipe embedded in the mold, temperature adjustment of a heat medium such as oil, and the like.

  After completion of the bulk polymerization, the reaction injection molded article of the present invention can be obtained by opening the mold and removing the mold.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In the following, “part” and “%” are based on mass unless otherwise specified.
Moreover, each characteristic was measured by the method shown below.

(1) The maximum depth (unit: μm) is measured at each sink portion using a digital depth gauge “DMD-218” manufactured by Hike Teclock. The smaller the number, the less sink. Further, taking into account the variation of sink marks, each part is measured five times to obtain an average value, and the average value of all boss portions is used as an evaluation value.

(2) Shear rate 92.6 parts by weight of dicyclopentadiene and 7.4 parts by weight of ethylidene norbornene are added to a piston having a cylindrical die having a diameter of 1.9 mm and a height of 9.3 mm at the tip (see FIG. 1). After the elastomer solution added with the elastomer was kept at 30 ° C. so that the viscosity at 30 ° C. of the resulting solution was 320 mPa · s, 50 ml was injected into the mixed monomer consisting of The amount of the effluent solution when a weight of 510 g is placed on the piston and extruded at an extrusion pressure of 10.2 kPa is determined, and the shear rate A is determined by equation (1).
Similarly, a shear rate B is calculated when a 1,660 g weight is placed on the piston and the extrusion pressure is 33.2 kPa.
Shear rate (1 / s) = 4q / πr ³ ρ (1)
(In the formula (1), q is the amount (g / s) of the elastomer solution flowing out from the die per unit time, r is the radius (cm) of the die nozzle, and ρ is the density of the elastomer solution (g / cm ^3). ).)

(3) Shear rate coefficient The shear rate coefficient is determined from the shear rates A and B according to the equation (2).
Shear rate coefficient = ln (shear rate B / shear rate A) / ln (33.2 / 10.2) (2)

(4) Freezing point Use a thermostatic chamber that can adjust the temperature in the unit of 0.1 ° C, and gradually lower the liquid temperature of the compounded solution in the container. When appropriate, invert the container of the compound solution upside down and check whether the compound solution flows out of the container. When the container of the blended liquid is turned upside down, the temperature at which the blended liquid does not flow out of the container is defined as the freezing point, and it is determined that the fluidity is lost.

[Example 1]
(Preparation of formulation liquid)
To 100 parts of a mixed monomer consisting of 92.6 parts of dicyclopentadiene and 7.4 parts of ethylidene norbornene, an olefin elastomer (I) consisting of 88% propylene units and 12% ethylene units (shear rate coefficient 1.52) 3.5 And 10 parts of a hydride of C9 hydrocarbon resin (I) (trade name “Arcon P-90” manufactured by Arakawa Chemical Industries, Ltd.) were dissolved. Next, triethylaluminum was added as an activity regulator so as to have a concentration of 14 mmol / kg, and mixed and dispersed to obtain a compounded solution (solution A).
17 parts of tungsten hexachloride are added to 44 parts of dry toluene under a nitrogen stream, then a solution of 1 part of t-butanol dissolved in 1 part of toluene is added and stirred for 30 hours, then 14 parts of dodecylphenol and 14 parts of toluene The mixture was stirred for 20 hours under a nitrogen purge, and further stirred for 24 hours under a nitrogen purge while purging out by-produced hydrogen chloride gas by adding 9 parts of acetylacetone to the polymerization catalyst. A solution was prepared.
Next, in a mixed monomer consisting of 92.6 parts of dicyclopentadiene and 7.4 parts of ethylidene norbornene, 3.5 parts of olefin elastomer (I) and 10 parts of C9 hydrocarbon resin hydride (I) are dissolved, Next, 0.6 part of a phenolic antioxidant was dissolved. Further, the polymerization catalyst was added and mixed and dispersed so as to have a concentration of 6 mmol / kg, and then 0.2 parts of diethylene glycol dimethyl ether was added and mixed and dispersed to obtain a blended liquid (liquid B).
The freezing points of these blended solutions were all -10 ° C.

(Molding)
A flat injection molded reaction injection molding die comprising an electroformed female die having a space of 480 mm in length, 1,250 mm in width, and 4 mm in thickness, and a forged aluminum male die paired therewith (see FIG. 2) The female mold was heated to 75 ° C. and the male mold was heated to 45 ° C.
This reaction injection mold has a structure having a polymerizable composition injection hole A at the center of the side surface. In addition, the mold has a boss B in the male mold surface, and inserts (IS) 1 to 11 for screwing members can be attached to the boss B. The insert has a shape as shown in FIG. 3B, the lower surface is closed, and a hole with a screw groove into which a bolt can be inserted from the upper surface is formed inside the insert.
FIG. 4A shows a state where the insert (IS) is attached at the time of molding.

50 parts of A liquid and 50 parts of B liquid are collided and mixed in a mixing head at a mixing pressure of 5.0 MPa, and a reaction injection molding die (A) is injected from the polymerizable composition injection hole (A) at an injection speed of 1.2 kg / s. M) and the bulk polymerization reaction was carried out for 90 seconds. At the time of molding, the resin flows into the boss (B) gap around the insert and hardens to fix the insert (IS) to the molded body (R). At this time, as shown in FIG. 4B, sink marks (SM) are generated on the design surface side of the molded body (R) corresponding to the boss.
Thereafter, the molded body was taken out from the mold, and the molded body 1 was obtained.
This operation was repeated 5 times. Table 1 shows the average value of sink marks measured at 11 places shown in FIG. The total average value of sink marks was 235 μm.

[Comparative Example 1]
Instead of 3.5 parts of olefin elastomer (I), 4.0 parts of olefin elastomer (II) having a shear rate coefficient of 1.25 consisting of 36% propylene unit, 56% ethylene unit and 8% diene monomer unit is used. Except for doing, it carried out similarly to Example 1, and obtained A liquid and B liquid.
The freezing points of these blended solutions were all 0 ° C.
Using these blended solutions, a molded body 2 was obtained in the same manner as in Example 1.
This operation was repeated 5 times. Table 1 shows the average value of sink marks measured at 11 locations of the obtained 5 molded bodies. The total average value of sink marks was 296 μm.

[Comparative Example 2]
Liquid A and liquid B were obtained in the same manner as in Example 1 except that the hydride (I) of C9-based hydrocarbon resin was not blended.
The freezing points of these blended solutions were all 3 ° C.
Using these blended solutions, a molded body 3 was obtained in the same manner as in Example 1.
This operation was repeated 5 times. Table 1 shows the average value of sink marks measured at 11 locations of the obtained 5 molded bodies. The total average value of sink marks was 234 μm.

From the results shown in Table 1, the following can be understood.
When a polymerizable composition obtained from a blending solution containing a norbornene monomer and an olefin elastomer but not containing an aromatic hydrocarbon resin is used, the degree of sink marks in the molded product is as small as 234 μm. Has a high freezing point of 3 ° C. (Comparative Example 2).
Even when a polymerizable composition obtained from a blended liquid containing an aromatic hydrocarbon resin in addition to a norbornene monomer and an olefin elastomer is used, the composition of the olefin elastomer defines the provisions of the present invention. When it deviates, the freezing point of the blended solution is improved to 0 ° C., but the degree of sink of the molded body is as bad as 296 μm (Comparative Example 1).
On the other hand, when a polymerizable composition obtained from a blended solution satisfying the provisions of the present invention formed by blending a norbornene-based monomer, an olefin-based elastomer and an aromatic hydrocarbon resin is used, up to −10 ° C. Fluidity can be maintained and the degree of sinking is as small as 235 μm.

It is a conceptual diagram of the apparatus for measuring the shear rate of an elastomer. Overall view of the mold used for the molding test and diagram showing the insert (IS) arrangement Illustration of the shape of the 11 inserts (IS) attached to the mold (a): Side view. (B): Top surface. (C): Bottom surface (A): The figure which shows the cross section of an insert in the state which attached the insert in the metal mold | die for shaping | molding. (B): The figure which shows the sink formed on the design surface side of a molded object

Explanation of symbols

r: Die nozzle radius q: Elastomer solution flow rate ρ: Elastomer solution density A: Polymeric composition inlet M: Mold IS: Insert B: Boss 1-11: Installation location of the insert (sink measurement location)
R: Molded body SM: Sink

Claims (6)

  A liquid composition for reaction injection molding by bulk polymerization of norbornene monomers in a mold, which contains norbornene monomers, olefin elastomers having an propylene unit content of 60% by weight or more, and aromatic hydrocarbon resins. A liquid composition for reaction injection molding characterized by comprising:   The reaction injection molding compound liquid according to claim 1, wherein the olefin-based elastomer is composed of 60 to 95% by weight of propylene units, 5 to 40% by weight of ethylene units and 0 to 5% by weight of non-conjugated diene monomer units.   The compounding liquid for reaction injection molding according to claim 1 or 2, wherein the blending amount of the olefin elastomer is 1 to 20 parts by weight per 100 parts by weight of the norbornene monomer.   The compounding liquid for reaction injection molding according to any one of claims 1 to 3, wherein the blending amount of the aromatic hydrocarbon resin is 1 to 20 parts by weight per 100 parts by weight of the norbornene monomer.   The manufacturing method of the reaction injection molding which makes the reaction injection molding of the reaction injection molding compound liquid of any one of Claims 1-4 bulk-polymerize within a type | mold, and reaction injection molding.   A reaction injection molded article obtained by the production method according to claim 5.

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