JP2649949B2 - Method for producing colored norbornene-based polymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a norbornene-based polymer by bulk polymerization in a mold, and more particularly, to a norbornene-based polymer uniformly colored without uneven coloring. A method for producing the same.

(Prior art) Bulk polymerization of norbornene-based monomers such as dicyclolopentadiene (abbreviated as DCP) and methyltetracyclododecene (abbreviated as MTD) in a mold in the presence of a metathesis catalyst system. It is known to obtain a colored polymer by adding an inorganic pigment, such as carbon black or titanium dioxide, to the mixture.

For example, JP-A-58-129003 discloses a method for producing a thermosetting DCP homopolymer using a metathesis catalyst system by a reaction injection molding method (RIM method). Homopolymers are used in combination with the catalytic components of a metathesis catalyst system such as tungsten halide and DCP.
A mixture consisting of one solution consisting of a mixture of the above and one solution consisting of a metathesis catalyst-based activator such as aluminum halide and DCP is mixed with a mixing head of a reaction injection molding machine (RIM machine). In a mold and then poured into a mold. that time,
The addition of fillers such as carbon black has been shown.

JP-A-59-51911 discloses RIM of a cyclic olefin containing a norbornene ring such as DCP or MTD, and in this bulk polymerization method, it has been shown that a pigment such as titanium dioxide is added. .

In these conventional methods, an inorganic pigment or the like is simply mixed with a norbornene-based monomer and used, but in such a method, the inorganic pigment is liable to form mamako when mixed, causes poor dispersion, and produces a reaction solution. The phenomenon of sedimentation during storage is observed.

Such a defect can be improved by mixing and dissolving a composition obtained by previously kneading an inorganic pigment with an elastomer in a norbornene-based monomer. However, there is a problem that this method causes deterioration of the elastomer itself during kneading, or cannot be applied to inorganic pigments and the like that are sensitive to heat. Further, since the amount of the inorganic pigment to be added depends on the amount of the elastomer, there is a drawback that the amount of the inorganic pigment is limited by the mixing ratio of the elastomer to the norbornene-based monomer.

Organic pigments have the same problems as inorganic pigments. However, in the case of organic pigments, it is particularly difficult to apply a kneading method with an elastomer because of easy thermal discoloration.

In a stock solution in which a colorant such as an inorganic pigment or an organic pigment is poorly dispersed, the resulting norbornene-based polymer is also heterogeneous with uneven coloring. In addition, a coloring agent generally causes polymerization inhibition of a norbornene-based monomer, and thus prolongs the molding time and lowers the secondary transition temperature of the produced polymer. Further, at present, there are many problems in coloring norbornene-based polymers, such as contamination of the unreacted solution storage tank by a coloring agent and color contamination at the time of color switching.

(Problem to be Solved by the Invention) An object of the present invention is to obtain a norbornene-based polymer which is uniformly colored without uneven coloring by a bulk polymerization method of a norbornene-based monomer in a mold.

Another object of the present invention is to prevent polymerization inhibition by a colorant and obtain a norbornene-based polymer having good physical properties.

The present inventors have conducted intensive studies to overcome the problems of the prior art and to develop a method capable of obtaining a norbornene-based polymer having no coloring unevenness without being limited by the type of the coloring agent. The present inventors have found that it is effective to use a mother liquor for coloring in which a coloring agent is homogeneously dispersed in a norbornene-based monomer using a high-speed dispersing machine such as a homogenizer, and have completed the present invention based on this finding.

(Means for Solving the Problems) Thus, according to the present invention, a reaction stock solution (A) containing a norbornene-based monomer and an activator and a reaction stock solution (B) containing a norbornene-based monomer and a metathesis catalyst are mixed and molded. In bulk polymerization in a mixture containing a norbornene-based monomer, an elastomer and a colorant is 1,000 to 1
A dispersion prepared by homogenizing with a homogenizer having a rotation speed of 00,000 rpm is contained as a mother liquor for coloring in at least one of the reaction stock solutions diluted with a norbornene-based monomer, or as a third stream (C). A method for producing a colored norbornene-based polymer is provided.

In addition, according to the present invention, when a reaction stock solution (A) containing a norbornene-based monomer and an activator and a reaction stock solution (B) containing a norbornene-based monomer and a metathesis catalyst are mixed and bulk-polymerized in a mold, a norbornene-based solution is used. After homogenizing a mixture containing a monomer and a colorant with a homogenizer having a rotation speed of 1,000 to 100,000 rpm, a dispersion prepared by removing a low-boiling fraction is used as a mother liquor for coloring, and in at least one of the reaction stock solutions. The present invention provides a process for producing a colored norbornene-based polymer, characterized in that the polymer is diluted with a norbornene-based monomer or used as a third stream (C).

Furthermore, according to the present invention, the mixture comprising a norbornene-based monomer and a colorant is homogenized by a homogenizer having a rotation speed of 1,000 to 100,000 rpm, and then a dispersion prepared by removing a low-boiling fraction is obtained. A mother liquor for coloring is provided.

 Hereinafter, the components of the present invention will be described in detail.

(Norbornene-based monomer) The norbornene-based monomer used in the production method of the present invention is a substituted or unsubstituted bicyclic or higher polycyclic norbornene. As specific monomers, for example, 2-norbornene, Bicyclic compounds such as -methyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-hexyl-2-norbornene, 5-ethylidene-2-norbornene, and 5-phenylnorbornene; Tricyclics such as cyclopentadiene and dihydrodicyclopentadiene, and tetracyclics such as tetracyclododecene, methyltetracyclododecene, ethyltetracyclododecene, dimethyltetracyclododecene, ethylidenetetracyclododecene, and phenyltetracyclododecene. Ring, tricyclopentadie And heptacyclics such as tetracyclopentadiene. These norbornene-based monomers can be used alone or in combination of two or more.

Among them, tricyclic or pentacyclic is awarded from the viewpoints of availability, reactivity, heat resistance and the like.

In the present invention, a polymer formed by using a crosslinkable monomer can be of a thermosetting type. The crosslinkable monomer is a polycyclic norbornene monomer having two or more reactive double bonds, and specific examples thereof include dicyclopentadiene, tricyclopentadiene, and tetracyclopentadiene. Therefore, when the norbornene-based monomer and the crosslinkable monomer are the same, it is not necessary to use any other crosslinkable monomer.

The tricyclic or higher norbornene-based monomer can also be obtained by heat-treating dicyclopentadiene. The conditions of the heat treatment include, for example, dicyclopentadiene in an inert gas atmosphere at a temperature of 120 to 250 ° C.
A method of heating for 5 to 20 hours is exemplified. By this heat treatment, a monomer mixture containing tricyclopentadiene and unreacted dicyclopentadiene is obtained.

Furthermore, monocyclic cycloolefins such as cyclobutene, cyclopentene, cyclopentadiene, cyclooctene, cyclododecene and the like, which can be subjected to ring-opening polymerization together with one or more of the above-mentioned norbornene-based monomers, can be used in combination within a range not to impair the object of the present invention. .

(Metathesis Catalyst System) The catalyst used in the present invention may be any metathesis catalyst system known as a catalyst for ring-opening polymerization of norbornene monomers (for example, JP-A-58-127728 and JP-A-58-12).
9013, 59-51911, 60-79035, 60-186511
No., No. 61-126115), and there is no particular limitation.

Specific examples of the metathesis catalyst include tungsten, molybdenum, tantalum halides, oxyhalides, oxides, organic ammonium salts, and the like.
Suitable examples include tungsten compounds such as tungsten hexachloride, tungsten oxytetrachloride, tungsten oxide, tridecylammonium tungstate, tri (tridecyl) ammonium tungstate, trioctylammonium tungstate: molybdenum pentachloride, molybdenum oxytrichloride And molybdenum compounds such as tridodecyl ammonium molybdate, methyl tricaprylammonium molybdate, tri (tridecyl) ammonium molybdate and trioctyl ammonium molybdate; and tantalum compounds such as tantalum pentachloride. Among them, it is preferable to use a catalyst that is soluble in the norbornene-based monomer used in the reaction, and from that viewpoint, an organic ammonium salt is awarded.

When the metathesis catalyst is a halide, the catalyst can be solubilized in the norbornene-based monomer by pre-treatment with an alcohol-based compound or a phenol-based compound. If necessary, a Lewis base such as benzonitrile or tetrahydrofuran or a chelating agent such as acetylacetone or acetoacetate alkyl ester can be used in combination, whereby early polymerization can be prevented.

Examples of the activator (cocatalyst) include alkylaluminum halides, alkoxyalkylaluminum halides, aryloxyalkylaluminum halides, and organotin compounds. Suitable examples include ethylaluminum dichloride, diethylaluminum monochloride, and ethylaluminum. Examples include sesquichloride, diethylaluminum iodide, methylaluminum sesquichloride, tetrabutyltin, a preliminary reaction product of an alkylaluminum halide and an alcohol.

Among these activators, alkoxyalkylaluminum halides and aryloxyalkylaluminum halides have an appropriate pot life at room temperature even when a catalyst component is mixed, and are advantageous in operation (for example, see JP-A-59-51911). issue). In the case of alkylaluminum halides, there is a problem that polymerization starts immediately when the catalyst is mixed.In this case, use an activity modifier such as ethers, esters, ketones, nitriles, and alcohols in combination. Can control the initiation of polymerization. (See, for example, JP-A-58-129003,
61-120814) In addition to a catalyst and an activator, halogenated hydrocarbons such as chloroform and carbon tetrachloride (for example, see JP-A-60-7903)
No. 5) or tin tetrachloride, silicon tetrachloride, lead tetrachloride,
A halide such as germanium tetrachloride or magnesium chloride may be used in combination. These are usually used in a proportion of 5 mol or less, preferably 0.1 to 4 mol, per mol of the activator.

The metathesis catalyst is used in an amount of usually about 0.01 to 50 mmol, preferably 0.1 to 1 mol, per mol of the norbornene monomer.
Used in the range of 0 mmol. The activator (cocatalyst)
The catalyst component is used in a range of usually 0.1 to 200 (molar ratio), preferably 2 to 10 (molar ratio).

It is preferable that both the metathesis catalyst and the activator are dissolved in a monomer before use. However, the metathesis catalyst and the activator may be suspended or dissolved in a small amount of a solvent as long as the properties of the product are not substantially impaired.

(Colorant) The colorant used in the present invention contains an insoluble component in the monomer, and may be any of an inorganic pigment, an organic pigment, and a mixture thereof.

Specific examples of the inorganic pigment include carbon black, graphite, graphite, iron oxide yellow, titanium dioxide, zinc oxide, ferric oxide, trilead tetroxide, lead red, chrome green, and navy blue.
As the carbon black, various types such as carbon black and acetylene black such as a furnace method, a channel method and a thermal method can be used.

Examples of the organic pigment insoluble in the monomer include benzidine yellow, chromophtal yellow 6G, chromophtal yellow 3G, chromophtal yellow GR, and the like.

Various pigments may be used in combination, and any combination of inorganic pigment / inorganic pigment, organic pigment / organic pigment, and inorganic pigment / organic pigment can be used. Further, a pigment soluble in a monomer may be used as one of the components.

As a specific example, for example, two or more inorganic pigments may be mixed and used such that a small amount of carbon black (black) is mixed with titanium oxide (white) to obtain a gray pigment. Also, red with titanium white and quinacridone, yellow with titanium white and polyazo, green with titanium white and cyanine green,
Inorganic pigments and organic pigments may be used in combination such as blue with titanium white and cyanine blue.

The proportion of the pigment used depends on the degree of hiding power, but is usually 10% by weight or less, preferably 0.1 to 7% by weight, based on the total amount of the pigment and the norbornene-based monomer.

(Homogenizer) As the homogenizer used in the present invention, a machine capable of imparting high-speed forced convection shearing action to the pigment in order to uniformly disperse (homogenize) the pigment as a colorant in the norbornene monomer is used. Although there is no limitation, generally, the rotation speed is 1,000 rpm to 100,000 rpm, preferably 2,
A high speed disperser having a rotation capacity of 000 rpm to 20,000 rpm is preferred.

The convection of the homogenizer is such that, for pigments that easily float on the monomer, such as carbon black, convection in the direction flowing from the upper layer to the lower layer, and for pigments that easily settle on the monomer, such as titanium white, Convection in the direction from the lower layer to the upper layer is desirable.

Specific equipment is a general homogenizer that features a powerful shear flow in the radial direction of the tank; for large pigments and relatively hard pigments, the shear force of the blades of the stirring unit is used. Homodisper; Other examples include a pipeline homogenizer that features strong shear, impact, and turbulence caused by a high-speed rotating homomixer type turbine and stator. In the present invention, these are collectively referred to as a homogenizer.

The concentration of the pigment dispersed in the norbornene-based monomer is not particularly limited, and can be appropriately determined according to the amount of the pigment contained in the molded article (norbornene-based polymer). Added to a concentration of 5 to 50% by weight, preferably 10 to 40% by weight.
After dispersion, the obtained mother liquor for coloring is appropriately diluted with a monomer before use.

Regarding the dispersion time, although there is a slight difference in the familiarity with the monomer depending on the type of the pigment, most can be uniformly dispersed within 30 minutes. At this time, if the operation is performed while blowing an inert gas such as nitrogen into the dispersion tank, the operation can be performed safely without fear of mixing of the catalyst deactivating component.

Further, since the coloring agent often contains a component that deactivates the catalyst and the activator, it is preferable to use the colorant after removing the deactivating component before mixing with the monomer. As a method of removing the inactivated component, there is a method of removing a low boiling point fraction from the coloring mother liquor homogenized by a homogenizer. For this purpose, a first-cut method or a treatment with an activator can be used.

The first distillation cut method is a method for cutting components flowing out under the conditions of usually a pressure of -750 to 1000 mmHg, preferably -730 to 200 mmHg, a bottom temperature of 50 to 130 ° C, and preferably 70 to 110 ° C. The amount to be cut is usually 0.1 to 10% by weight, preferably 1 to 5% by weight of the charged amount.

(Polymerization Conditions) In the present invention, a norbornene-based polymer, that is, a molded article is produced by a method in which a norbornene-based monomer is introduced into a mold having a predetermined shape, and is subjected to bulk polymerization in the mold in the presence of a metathesis catalyst system.

When a norbornene-based monomer is subjected to bulk polymerization in the presence of a metathesis catalyst system, two kinds of reaction stock solutions are usually prepared. That is, the activator is put in one container (Solution A),
The other container is charged with a catalyst component (Solution B), and each reaction stock solution contains a norbornene-based monomer. The two reaction stock solutions are mixed, and then injected into a molding die.
Then, ring-opening polymerization is performed in a lump to obtain a molded product.

In order to use the homogenizer efficiently, the coloring mother liquor contains a high concentration of a coloring agent and is used after being diluted with a norbornene-based monomer or used as a third stream (solution C). When the coloring mother liquor is diluted with the norbornene-based monomer, it is added to at least one of the solution A and the solution B. However, when the coloring mother liquor is added to the solution A, the activity of the catalyst is reduced and polymerization inhibition is caused. It is desirable to add only to solution B.

In the present invention, it is possible to use an impingement mixing apparatus for mixing the A and B reaction stock solutions. However, if the pot life at room temperature is 1 hour or more, a static mixer or a power mixer may be used. Mix the two kinds of reaction stock solution in a mixer such as
Injection or injection can be performed once or a predetermined number of times (for example, see JP-A-59-51911).
In addition, a mixture of both reaction stock solutions can be continuously supplied into a molding die. In the case of this system, there are advantages that the size of the apparatus can be reduced and operation can be performed at a low pressure as compared with the collision mixing apparatus.

In the present invention, the mother liquor for coloring can be used as a third stream by putting it in a third container. According to this method, since the reaction solution does not contain a coloring agent, the storage tank can be prevented from being stained, and the operation for changing the color by changing the type is easy. In addition, since the mixture of the colorant and the monomer is homogenized and stored in the absence of the metathesis catalyst system, compared to the case where the molding is performed with the two liquids A and B to which the coloring mother liquor is added, There is no decrease in activity and there is little occurrence of polymerization inhibition. as a result,
It is possible to shorten the curing time, obtain a molded product having good surface properties and a higher glass transition point.

The mold temperature is usually 30 ° C or higher, preferably 40 to 200 ° C,
Particularly preferably, it is 50 to 130 ° C.

The polymerization time may be appropriately selected, but is usually shorter than about 20 minutes, preferably 5 minutes or less, but may be longer.

(Optional components) The characteristics of the molded article of the present invention can be modified by blending various additives such as a filler, an antioxidant, a hydrogenated dicyclopentadiene-based thermopolymer resin, and an elastomer. The additive is used by being mixed in advance with one or both of the reaction stock solutions.

As the antioxidant, there are various antioxidants for plastics / rubbers such as phenol type, phosphorus type and amine type.

Metal stabilizers such as zinc stearate, lead salicylate, cadmium benzoate, calcium salts, and aluminum salts can also be used to prevent discoloration and improve weather resistance.

The elastomer is added to improve impact resistance and prevent sedimentation of the pigment. Examples of the elastomer include natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer (SBR), styrene-butadiene-styrene block copolymer (SBR), styrene-isoprene-styrene block copolymer (SIS), and ethylene- Propylene-
Diene terpolymers (EPDM), ethylene vinyl acetate copolymers (EVA), and hydrides thereof. These elastomers can be used as a mixture of two or more.

The blending ratio of the elastomer can be appropriately determined depending on the molecular weight of the elastomer, the desired viscosity of the reaction solution, and the like, but is usually 10% by weight or less, preferably 1 to 8% by weight.
It is.

(Example) Hereinafter, the present invention will be described more specifically with reference to examples. In the Examples, Comparative Examples and Reference Examples, parts and percentages are
Unless otherwise specified, it is based on weight.

Example 1 (Preparation of mother liquor for coloring) In order to confirm the dispersibility of the pigment in the norbornene-based monomer, a precipitation test of the pigment was performed.

100 parts of dicyclopentadiene (DCP), 5 parts of styrene-isoprene-styrene block copolymer (SIS) (Quintac 3420, trade name of Nippon Zeon Co., Ltd.) and 30 parts of various pigments shown in Table 1 are mixed. did. As a mixing method, a homogenizing method using a homogenizer (mixing and dispersing at 6000 rpm for 30 minutes, Experiment Nos. 1 to 6) and a method using a normal stirrer (stirring at 100 rpm for 30 minutes, Experiment Nos. 7 to 8) for comparison are used. Adopted.

After the mixing, the coloring mother liquors of Experiment Nos. 1 to 4 were distilled under the conditions of a coloring mother liquor temperature of 80 ° C. and a reduced pressure of −710 mmHg to remove 2% of the charge as a low boiling fraction. on the other hand,
In Experiment Nos. 5 and 6, ones that were not first cut were shown.

Table 1 shows the results. In the case of dispersing using a homogenizer (Experiment Nos. 1 to 6), the dispersion state was uniform and there was no sedimentation over time. In the dispersion with a normal stirrer (Experiment Nos. 7 to 8), the pigment was apt to become mamako, and a sedimentation phenomenon was also observed.

 The pigments used are as follows.

Carbon black: Mitsubishi Chemical Co., Ltd. # 1000 Titanium White: Dainichi Seika Co., Ltd. White-8 Quinacridone: Dainichi Seika Co., Ltd. TSD-T-120 Red Polyazo: Dainichi Seika Co., Ltd. TSD-P-420 Yellow Homogenizer (dispersing machine) is manufactured by Tokushu Kika Kogyo
TK homomixer type M was used.

Example 2 (Production of a colored polymer, three-pack type) In 100 parts of dicyclopentadiene (DCP), 5 parts of styrene-isoprene-styrene block copolymer (SIS) (Quintac 3420, trade name of Nippon Zeon Co., Ltd.) were put. Mix. This solution was placed in two containers, and to one of them, diethylaluminum chloride (DEAC) was added to DCP at a concentration of 4.1 mmol, n-propyl alcohol at a concentration of 4.1 mmol, and silicon tetrachloride at a concentration of 2.1 mmol. (Solution A). On the other hand, tri (tridecyl) ammonium molybdate was added to DCP to a concentration of 1 mmol (Solution B).

The two reaction solutions containing the metathesis catalyst system and the mother liquor for coloring (solution C) of Experiment Nos. 1 to 6 of Example 1 were combined with solution A / B
The mixture was mixed with a three-liquid mixing power mixer at a mixing ratio of liquid / liquid C of 1/1 / 0.095 (pigment concentration: 1.4%).
Using a gear pump and a power mixer, the mixture was quickly injected into a mold having a space volume of 00 mm × 200 mm × 3 mm and heated to 70 ° C. using a gear pump and a power mixer. After the system suddenly generates heat,
The reaction was continued for 3 minutes to obtain a molded DCP polymer.
Table 2 shows the appearance and physical properties of the obtained molded article.

When the coloring mother liquor of the present invention is used, a uniformly colored molded article can be obtained.

In addition, when the mother liquor for coloring which was first cut was used (Experiment Nos. 9 to 12), the TCP of DCP polymer was lower than when the mother liquor for coloring which was not first cut was used (Experiment Nos. 13 to 14).
It can be seen that g is high and the time until heat generation (molding time) is short.

On the other hand, the same experiment number was attempted using a coloring mother liquor (coloring mother liquor G, H) dispersed using a normal stirrer. However, color unevenness occurs due to uneven dispersion of the coloring mother liquor. Only products with low commercial value could be manufactured.

Example 3 (Production of colored polymer, two-pack type) 100 parts of dicyclopentadiene (DCP), 10 parts of styrene-isoprene-styrene block copolymer (SIS) (Quintac 3420, trade name of Zeon Corporation), and 10 parts of each of the coloring mother liquors of Experiment Nos. 1 to 2 and 5 to 8 of Example 1 are added and mixed. This mixture was placed in two containers, and one was added to DCP so that diethylaluminum chloride (DEAC) was 4.1 mmol, n-propyl alcohol was 4.1 mmol, and silicon tetrachloride was 2.1 mmol. (Solution A). On the other hand, DC
To P, tri (tridecyl) ammonium molybdate was added to a concentration of 1 mmol (solution B).

Both reaction solutions have a space volume of 200 mm x 200 mm x 3 mm, 70
Using a gear pump and a power mixer, the mixture was quickly injected into a mold heated to about normal pressure at almost normal pressure. After rapid heat generation, the reaction was continued for 3 minutes to obtain a DCP polymer as a molded article. Table 3 shows the appearance and physical properties of the obtained molded article.

In contrast to the conventional method, in which uneven coloring occurs, according to the present invention, it can be seen that a molded article which is uniformly colored can be obtained, and is excellent in impact resistance.

Compared with Example 2 (three-pack type), the time until heat generation is slightly longer, but still substantially the same as in the conventional method. In addition, when the same experiment was performed by adding the coloring mother liquors of Experiment Nos. 1 to 2 and 5 to 6 respectively to the solution B alone, the time until heat generation was remarkably shortened and almost the same as Example 2 (three-pack type). The result was equivalent.

(Effects of the Invention) Thus, according to the present invention, the dispersibility of the colorant is improved, and as a result, a uniform colored norbornene-based polymer without coloring unevenness can be obtained.

Further, according to the present invention, a colored molded article having good physical properties can be obtained without causing polymerization inhibition.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutoshi Fukasawa 2767-1 Shinhama, Kojima Shioike, Kurashiki City, Okayama Pref. 63-152620 (JP, A) JP-A-1-230626 (JP, A)

Claims (7)

(57) [Claims] 1. A reaction mixture (A) containing a norbornene-based monomer and an activator and a reaction stock solution (B) containing a norbornene-based monomer and a metathesis catalyst are mixed and bulk-polymerized in a mold. And a dispersion prepared by homogenizing a mixture containing a colorant and a homogenizer having a rotation speed of 1,000 to 100,000 rpm as a mother liquor for coloring, at least one of the reaction stock solutions is diluted with norbornene-based monomer and contained. ,
Alternatively, a method for producing a colored norbornene-based polymer, which is used as a third stream (C). 2. The colored mother liquor according to claim 1, wherein the mother liquor for coloring is a dispersion obtained by homogenizing a mixture containing a norbornene-based monomer, an elastomer and a colorant with a homogenizer and removing a low-boiling fraction. A method for producing a norbornene-based polymer. 3. The process for producing a colored norbornene-based polymer according to claim 1, wherein the colored mother liquor is diluted with a norbornene-based monomer and contained only in the reaction stock solution (B). 4. A reaction mixture (A) containing a norbornene-based monomer and an activator and a reaction stock solution (B) containing a norbornene-based monomer and a metathesis catalyst are mixed and bulk-polymerized in a mold. After homogenizing the mixture containing the agent and a homogenizer at a rotation speed of 1,000 to 100,000 rpm, a dispersion prepared by removing a low-boiling fraction was used as a mother liquor for coloring. A method for producing a colored norbornene-based polymer, which is contained by being diluted with a monomer or used as a third stream (C). 5. The method for producing a colored norbornene-based polymer according to claim 4, wherein the colored mother liquor is diluted with the norbornene-based monomer and contained only in the reaction stock solution (B). 6. A dispersion prepared by homogenizing a mixture containing a norbornene-based monomer and a colorant with a homogenizer having a rotation speed of 1,000 to 100,000 rpm and removing a low-boiling fraction. Mother liquor for coloring. 7. The coloring mother liquor according to claim 6, wherein said mixture further contains an elastomer.