阅读说明：本技术 催化剂组合物和使用该催化剂组合物制备烃类树脂的方法 (Catalyst composition and process for preparing hydrocarbon resin using the same ) 是由 崔景信 金元熙 高永洙 郑荷莹 A·C·卡林诺 于 2020-08-25 设计创作，主要内容包括：本发明涉及一种包含氧鎓离子类催化剂和添加剂的催化剂组合物以及使用该催化剂组合物制备烃类树脂的方法。(The present invention relates to a catalyst composition comprising an oxonium ion-based catalyst and an additive and a process for preparing a hydrocarbon resin using the catalyst composition.)

1. A process for preparing a hydrocarbon resin, the process comprising the step of polymerizing a monomer mixture comprising one or more of C5 or C9 unsaturated hydrocarbon monomers in the presence of a catalyst composition comprising a catalyst represented by formula 1 below and an additive represented by formula 2 below:

[ formula 1]

In the formula 1, the first and second groups,

r is an alkyl group of 4 to 12 carbon atoms,

R₁to R₄Each independently is hydrogen, a halogen group, or a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, and

o, p, q and r are each independently an integer of 1 to 5,

[ formula 2]

R_a-X

In the formula 2, the first and second groups,

ra is hydrogen, alkyl of 1 to 20 carbon atoms, cycloalkyl of 3 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, alkylaryl of 7 to 20 carbon atoms or arylalkyl of 7 to 20 carbon atoms,

x is cyano, pyridyl, alkoxy of 1 to 20 carbon atoms or aryloxy of 6 to 20 carbon atoms.

2. The process for preparing hydrocarbon resins according to claim 1, wherein the C5 unsaturated hydrocarbon monomer is one or more selected from isoprene, 1-pentene, 2-methyl-2-butene, cyclopentene, cyclopentadiene, 1, 3-pentadiene and 1, 4-pentadiene.

3. The process for preparing hydrocarbon resins according to claim 1, wherein the C9 unsaturated hydrocarbon monomer is one or more selected from vinyl toluene, indene and alpha-methyl styrene.

4. The process for preparing hydrocarbon resins according to claim 1, wherein the monomer mixture further comprises one or more monomers selected from isobutylene, 2-methyl-1-pentene, 2-methyl-2-pentene, 1, 3-hexadiene, 1, 4-hexadiene and dicyclopentadiene.

5. The process for preparing hydrocarbon resin according to claim 1, wherein the additive represented by formula 2 is one or more selected from acetonitrile, benzonitrile, 2-phenylpyridine, diethyl ether, and dibutyl ether.

6. The process for preparing hydrocarbon resins according to claim 1, wherein R is propyl or butyl.

7. The process for producing hydrocarbon resin according to claim 1, wherein R₁To R₄Each independently a halogen group or an alkyl group of 1 to 20 carbon atoms substituted with a halogen group.

8. The method for producing a hydrocarbon resin according to claim 1, wherein the borate-type bulky anion contained in the catalyst represented by formula 1 is one or more selected from the group consisting of tetrakis (phenyl) borate, tetrakis (pentafluorophenyl) borate, tetrakis [3, 5-bis (trifluoromethyl) phenyl ] borate, and derivatives thereof.

9. The process for preparing hydrocarbon resin according to claim 1, wherein the catalyst represented by formula 1 is used after being dissolved in a halogenated hydrocarbon solvent.

10. The process for preparing hydrocarbon resins according to claim 1, wherein the polymerization is carried out at a temperature of-10 ℃ to 30 ℃ for 30 minutes to 2 hours.

Technical Field

Cross Reference to Related Applications

This application claims the benefit of priority based on korean patent application No.2019-0104242 filed on 26.8.2019, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates to a catalyst composition comprising an oxonium ion-based catalyst and an additive and a process for preparing a hydrocarbon resin using the catalyst composition.

Background

The hydrocarbon resin is a low molecular weight thermoplastic resin prepared using unsaturated hydrocarbons contained in pyrolysis oil such as naphtha as a raw material. The hydrocarbon resin has a hard and brittle solid phase in a liquid phase having viscosity, and shows colorless transparency, colors such as pale yellow and dark brown, and the like, depending on the type of the monomer. Hydrocarbon resins are safe to Ultraviolet (UV) rays, have a property of imparting tackiness, and are used as various materials for imparting tackiness or stickiness to tapes, products such as paints, inks, rubbers, and tires, medical supplies, woodworking products, sanitary products, and the like.

Generally, in order to prepare hydrocarbon resins, a catalyst is generally used to polymerize a diolefin C5 or C9 fraction, followed by processes of catalyst removal, washing, resin separation, and the like, and recently, tests for improving physical properties have been conducted by other polymerization methods such as thermal polymerization and radical polymerization.

In particular, the hydrocarbon resin may be prepared by cationic polymerization of the monomers contained in the above-mentioned C5 or C9 fractionsAnd an aluminum-based or boron-based lewis acid is generally used as a catalyst or an initiator for such cationic polymerization. Examples of Lewis acids include AlX₃、BX₃(X ═ F, Br, Cl, I), etc., there is a problem in that these lewis acids are corrosive, and halogen components such as HCl and HF are generated during quenching and remain in the product to deteriorate the product quality. In addition, the Lewis acid catalysts require a large amount of catalyst and use a large amount of basic substances (NaOH, KOH, NH) after the reaction₄OH, etc.) for removing the catalyst. In addition, additional washing with water is required and large amounts of waste water are produced.

Meanwhile, cationic polymerization, which is generally used for the polymerization of hydrocarbon resins, is very sensitive to moisture and impurities, and has the following cases: in the process of growing the polymer chain, it is difficult to prepare a resin having a high molecular weight because the reaction is terminated by reaction with a small amount of moisture or impurities, or chain transfer occurs. Further, in the case of preparing a catalyst using a conventional metal complex prepared from a silver reagent, since it is difficult to completely remove lithium salt, sodium salt, potassium salt, magnesium salt or silver salt generated during the preparation process, there are problems in that the salt may be included in the polymerization reaction as an impurity and the activity of the catalyst may also be deteriorated.

[ Prior Art document ]

[ patent documents ]

(patent document 1) Korean patent laid-open publication No.2007-0085152

Disclosure of Invention

Technical problem

An object of the present invention is to provide a catalyst composition comprising an oxonium ion-type catalyst and an additive and a process for preparing a hydrocarbon resin using the catalyst composition.

Technical scheme

In order to solve the above-mentioned tasks, the present invention provides a process for preparing a hydrocarbon resin comprising the step of polymerizing a monomer mixture comprising one or more of C5 or C9 unsaturated hydrocarbon monomers in the presence of a catalyst composition comprising a catalyst represented by the following formula 1 and an additive represented by the following formula 2:

[ formula 1]

In the formula 1, the first and second groups,

r is an alkyl group of 4 to 12 carbon atoms,

R₁to R₄Each independently hydrogen, a halogen group, or a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms,

o, p, q and r are each independently an integer of 1 to 5,

[ formula 2]

R_a-X

In the formula 2, the first and second groups,

ra is hydrogen, alkyl of 1 to 20 carbon atoms, cycloalkyl of 3 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, alkylaryl of 7 to 20 carbon atoms or arylalkyl of 7 to 20 carbon atoms, and

x is cyano, pyridyl, alkoxy of 1 to 20 carbon atoms or aryloxy of 6 to 20 carbon atoms.

Advantageous effects

The oxonium ion-based catalyst of the present invention can be used as a substitute for a conventional aluminum-based or boron-based lewis acid catalyst, and in the case of producing a hydrocarbon resin using a catalyst composition obtained by mixing it with an additive, the hydrocarbon resin can be obtained at a high conversion rate.

Detailed Description

The present invention will be described in more detail below to assist in understanding the invention.

It should be understood that the words or terms used in the specification and claims of this invention should not be construed as meaning defined in commonly used dictionaries. It should also be understood that the words or terms should be construed as having meanings consistent with their meanings in the technical idea of the present invention, based on the principle that the inventor can appropriately define the meanings of the words or terms in order to best explain the present invention.

The "composition" in the present invention includes a mixture comprising the substances of the respective compositions and the reaction products and decomposition products formed from the substances of the respective compositions.

The "alkyl group" in the present invention means a monovalent hydrocarbon residue of a straight chain type, a cyclic type or a branched chain type, and non-limiting examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl and hexyl groups, without limitation.

The "cycloalkyl group" in the present invention means a non-aromatic cyclic hydrocarbon residue consisting of carbon atoms. By way of non-limiting example, "cycloalkyl" includes, without limitation, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl.

The "aryl group" in the present invention means an optionally substituted benzene ring, or a ring system which may be formed by fusing one or more optional substituents. May include phenyl, naphthyl, tetrahydronaphthyl, biphenyl, indanyl (indanyl), anthryl or phenanthryl or substituted derivatives thereof without limitation.

"alkylaryl" in the context of the present invention refers to an aryl group substituted with at least one alkyl group.

"arylalkyl" in the context of the present invention refers to an alkyl group substituted with at least one aryl group.

The "alkoxy group" in the present invention means a monovalent group of the formula-OR (R is an alkyl group), and specific examples thereof include methoxy group, ethoxy group, isopropoxy group and the like.

In the present invention, "aryloxy" means-OR '(R' is aryl).

The process for preparing a hydrocarbon resin of the present invention comprises the step of polymerizing a monomer mixture comprising one or more of C5 or C9 unsaturated hydrocarbon monomers in the presence of a catalyst composition comprising a catalyst represented by the following formula 1 and an additive represented by the following formula 2:

[ formula 1]

In the formula 1, the first and second groups,

r is an alkyl group of 4 to 12 carbon atoms,

R₁to R₄Each independently hydrogen, a halogen group, or a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms,

o, p, q and r are each independently an integer of 1 to 5,

[ formula 2]

R_a-X

In the formula 2, the first and second groups,

ra is hydrogen, alkyl of 1 to 20 carbon atoms, cycloalkyl of 3 to 20 carbon atoms, aryl of 6 to 20 carbon atoms, alkylaryl of 7 to 20 carbon atoms or arylalkyl of 7 to 20 carbon atoms,

x is cyano, pyridyl, alkoxy of 1 to 20 carbon atoms or aryloxy of 6 to 20 carbon atoms.

In the present invention, the catalyst represented by formula 1 is used for cationic polymerization of a monomer mixture comprising one or more of C5 or C9 unsaturated hydrocarbon monomers. Since the catalyst of the present invention includes an organic borate as an anionic moiety, which includes one or more halogen group substituents having a strong electron withdrawing phenomenon in the phenyl group, the C — B bond is strong, and since the additive represented by formula 2 of the present invention is used together in cationic polymerization, excellent efficiency can be exhibited. In contrast, if the substituent is not present on the phenyl group of the anionic portion, or an alkyl substituent or the like is bonded to the phenyl group of the anionic portion, and if mixed with the co-catalyst of the present invention, there may be problems of side reactions and catalyst decomposition.

The additive represented by formula 2 may play a role in increasing the polymerization conversion rate in the polymerization reaction of the monomer mixture for preparing the hydrocarbon resin. The additive represented by formula 2 contains a nitrogen atom or an oxygen atom having an unshared electron pair, which facilitates bonding with a hydrogen cation to promote a chain transfer reaction for transferring the hydrogen cation, thereby increasing the conversion rate of the polymerization reaction.

In order to effectively exert such an effect in the present invention, it is required that no bulky functional group is present around a nitrogen atom or an oxygen atom so as not to inhibit bonding with a hydrogen cation. Further, in the case of using a compound having a rigid structure containing a plurality of nitrogen atoms or oxygen atoms and whose positions are close, and if a non-shared electron pair accidentally forms a bond with a catalyst, a very strong coordinate bond may be formed to block all active sites of the catalyst, and there may be a problem that the activity of the catalyst may be significantly reduced, and a polymerization reaction may not normally proceed.

Therefore, in the present invention, as described above, as a compound having an appropriate structure that can function as a chain extender by appropriately bonding and transferring with a hydrogen cation to increase the polymerization conversion rate without decreasing the activity of the catalyst, the catalyst represented by formula 1 is used together with the additive represented by formula 2.

In particular, in formula 1, R may be an alkyl group of 4 to 12 carbon atoms, an alkyl group of 4 to 6 carbon atoms, for example, a propyl or butyl group, R₁To R₄May each independently be hydrogen, a halogen group, or an alkyl group of 1 to 20 carbon atoms substituted with a halogen group, and o, p, q, and r may each independently be an integer of 4 or 5. Most preferably, R₁To R₄May each independently be a halogen group, and o, p, q, and r may be 5.

In addition to this, the present invention is,as the organic borate contained in the compound represented by formula 1, there may be specifically mentioned one or more selected from the group consisting of tetrakis (phenyl) borate, tetrakis (pentafluorophenyl) borate, tetrakis [3, 5-bis (trifluoromethyl) phenyl borate and derivatives thereof, with tetrakis (pentafluorophenyl) borate being preferred.

In particular, in formula 2, Ra may be an alkyl group of 1 to 20 carbon atoms, an alkyl group of 1 to 12 carbon atoms, an alkyl group of 1 to 6 carbon atoms, an aryl group of 6 to 20 carbon atoms, or an aryl group of 6 to 12 carbon atoms, and X may be a cyano group, a pyridyl group, an alkoxy group of 1 to 12 or 2 to 6 carbon atoms, or an aryloxy group of 6 to 12 carbon atoms.

More specifically, the additive represented by formula 2 may be one or more selected from acetonitrile, benzonitrile, 2-phenylpyridine, diethyl ether, and dibutyl ether, without limitation.

The equivalent ratio of the catalyst represented by formula 1 and the additive represented by formula 2 may be 1:1 to 1:200, in view of efficient production of hydrocarbon resin and control of the number average molecular weight in a desired range, specifically 1:1 to 1:20, or 1:1 to 1:7, 1:1 to 1: 2.

If the amount of the additive is less than 1 equivalent with respect to 1 equivalent of the catalyst represented by formula 1, the effect of stabilizing the carbocation using the additive is insignificant, and efficient preparation of the hydrocarbon resin may become difficult. If the amount of the additive is more than 200 equivalents with respect to 1 equivalent of the catalyst represented by formula 1, there may be a problem in that the additive may be combined with carbocations, and the polymerization reaction may be terminated at an early stage.

In the present invention, the catalyst represented by formula 1 may be used dissolved in a halogenated hydrocarbon solvent, and a nonpolar hydrocarbon solvent may be mixed with the halogenated hydrocarbon solvent to dissolve the catalyst represented by formula 1.

In the present invention, in order to initiate cationic polymerization, it is necessary that hydrogen atoms existing between oxygen atoms of the catalyst represented by formula 1 react with the monomer mixture to dissociate the ether compound (R-O-R) and generate carbocation of the C5 or C9 unsaturated hydrocarbon monomer, and in order to maintain the carbocation thus generated in an ionic state for a long time to improve polymerization reactivity, it is necessary to use a halogenated hydrocarbon solvent having polarity.

However, in initiating the polymerization reaction, it is advantageous to use a halogenated hydrocarbon solvent, but the stability of the catalyst represented by formula 1 is very low when it is in a dissolved state in the halogenated hydrocarbon solvent due to toxicity of halogen and the like, and the activity of the catalyst represented by formula 1 may be gradually reduced with time if it is not used for polymerization immediately after mixing.

In contrast, in the case of the catalyst represented by formula 1 used in the present invention, although the polymerization is performed using the catalyst after preparing a composition by dissolving in a halogenated hydrocarbon solvent such as Dichloromethane (DCM) and storing for a certain time, there is an advantage in that hydrocarbon resins having equivalent physical properties, which still have high polymerization conversion, can be prepared.

Further, the halogenated hydrocarbon solvent may be one or more selected from the group consisting of methyl chloride, methylene chloride, chloroform, 1-chlorobutane and chlorobenzene, without limitation.

The non-polar hydrocarbon solvent may be an aliphatic hydrocarbon solvent or an aromatic hydrocarbon solvent. For example, the aliphatic hydrocarbon solvent may be one or more selected from butane, pentane, neopentane, hexane, cyclohexane, methylcyclohexane, heptane and octane, and the aromatic hydrocarbon solvent may be one or more selected from benzene, toluene, xylene and ethylbenzene, without limitation.

In the present invention, in the monomer mixture, a C5 unsaturated hydrocarbon monomer, a C9 unsaturated hydrocarbon monomer, or a mixture thereof may be present.

The C5 unsaturated hydrocarbon monomer may be one or more selected from isoprene, 1-pentene, 2-methyl-2-butene, cyclopentene, cyclopentadiene, 1, 3-pentadiene and 1, 4-pentadiene, without limitation.

The C9 unsaturated hydrocarbon monomer may include an aliphatic hydrocarbon or aromatic hydrocarbon ring, particularly one or more selected from the group consisting of vinyl toluene, indene, and alpha-methyl styrene, without limitation.

For the preparation of the hydrocarbon resin, any type may be appropriately selected and applied to the present invention as long as the C5 unsaturated hydrocarbon monomer or the C9 unsaturated hydrocarbon monomer used in the art is selected.

In addition, the monomer mixture may further include one or more selected from the group consisting of isobutylene, 2-methyl-1-pentene, 2-methyl-2-pentene, 1, 3-hexadiene, 1, 4-hexadiene and dicyclopentadiene.

In the present invention, the catalyst represented by formula 1 may be used in an amount of 0.01 wt% or more, 0.02 wt% or more, 0.2 wt% or less, 0.1 wt% or less, 0.05 wt% or less, 0.03 wt% or less, based on the total weight of the monomers.

As described above, the catalyst represented by formula 1 and the additive may be dissolved in a halogenated hydrocarbon solvent for use. In this case, the catalyst represented by formula 1 may be used in an amount of 5 to 50ppm by weight or 10 to 40ppm by weight based on the catalyst composition. Further, the amount of the catalyst represented by formula 1 may be 5 to 250ppm (by weight), or 10 to 100ppm (by weight), or 10 to 50ppm (by weight), based on the monomer mixture. If the above numerical range is satisfied, the polymerization reaction can be efficiently performed, and if an excessive amount exceeding the numerical range is injected, the process efficiency is not significantly improved compared to the increase in the cost of raw materials.

In the present invention, the polymerization of the monomer mixture may be carried out at-10 ℃ or higher, -5 ℃ or higher, -2 ℃ or higher, 30 ℃ or lower, 10 ℃ or lower, 5 ℃ or lower, 2 ℃ or lower, or 0 ℃. The polymerization reaction may be carried out at the above temperature for 30 minutes to 50 minutes, 3 hours to 2 hours, or 1 hour. For example, the polymerization may be carried out at a temperature of-10 ℃ to 30 ℃ for 30 minutes to 2 hours.

In the process for producing a hydrocarbon resin of the present invention, the step of removing the catalyst may also be performed after the step of polymerizing the monomer mixture. Since the catalyst represented by formula 1 used in the present invention can be effectively removed by a physical simple filtration step, its use and removal are even more advantageous than lewis acid catalysts of the conventional art.

In particular, after the polymerization of the monomer mixture, the organic solvent is removed so that the organic solvent can be controlled to 40% by weight or less, 20% by weight or less, or 5% by weight or less of the hydrocarbon resin.

And then, in the case of a hydrocarbon resin having fluidity, filtering the insoluble matter with a glass filter of 80 mesh or more, 100 mesh or more, or 200 mesh or more. Alternatively, the catalyst may be removed by passing the polymer having fluidity through a silica, diatomaceous earth or zeolite filter.

Meanwhile, in the case of a hydrocarbon resin having low fluidity, fluidity is obtained using one or more selected from linear alkyl solvents such as pentane, cyclopentane, hexane, cyclohexane, heptane and octane, and ether solvents such as diethyl ether and petroleum ether, and then the filtration step may be performed through a glass filter, silica, diatomaceous earth or zeolite filter.

Typically, the hydrocarbon resin thus prepared is dissolved in an organic solvent comprising pentane, cyclopentane, hexane, cyclohexane, heptane, octane, diethyl ether or petroleum ether and washed to remove the catalyst. In the present invention, the catalyst can be effectively removed by the above-mentioned simple filtration step, and a separate washing step may not be performed.

Examples

Hereinafter, preferred embodiments will be described in detail to aid understanding of the present invention. However, the following embodiments are merely examples, and the present invention may be varied and modified in many different forms and should not be construed as being limited to the embodiments set forth herein, and such variations and modifications should be included in the appended claims.

Preparation example 1

In a glove box, 1g of [ H (Et)₂O)₂][B(C₆F₅)₄]Put into a round bottom flask, and 10mL of methylene chloride was put therein. 5 equivalents of dry butyl ether (purchased from Sigma Aldrich) were added to the solution at room temperature and stirred for 30 minutes. After stirring, all solvent was removed under vacuum. The white powder thus obtained was washed with anhydrous hexane by 5mL × three times, and then dried again under vacuum to obtain [ H (nBu)₂O)₂][B(C₆F₅)₄]。

Example 1

5mL of α -methylstyrene monomer and 5mL of DCM solvent were injected into a vial, the catalyst of preparation 1 (0.02% by weight based on α -methylstyrene) was dissolved in DCM and added thereto, and the additive acetonitrile represented by formula 2 (equivalent to the catalyst of preparation 1) was added thereto, followed by polymerization in an ethanol bath maintained to 0 ℃ for 1 hour. After the reaction was completed, the resulting product was precipitated in an excess of methanol, and the precipitate was separated by filtration under reduced pressure, dried at room temperature for 24 hours, and dried at 50 ℃ for 1 hour in vacuo to obtain a hydrocarbon resin.

Examples 2 to 5, and comparative examples 1 to 3

A hydrocarbon resin was prepared by the same method as example 1, except that the type of additive represented by formula 2 was changed as shown in the following table 1 during the preparation of the catalyst composition.

[ Table 1]

	An additive represented by formula 2
		Example 1	Acetonitrile
Example 2	Benzonitrile
		Example 3	2-phenylpyridines
Example 4	Ether (A)
		Example 5	Butyl ether
Comparative example 1	-
		Comparative example 2	Lutidine (DIP)
Comparative example 3	Phenanthroline

Experimental example 1

With respect to the hydrocarbon resins prepared in examples and comparative examples, weight average molecular weight, number average molecular weight, and molecular weight distribution values were measured by the following methods and are summarized in table 2.

(1) Weight average molecular weight and number average molecular weight

The hydrocarbon resin was measured under the following Gel Permeation Chromatography (GPC) analysis conditions.

-a column: PL MiniMixed Bx 2

-a solvent: THF (tetrahydrofuran)

-flow rate: 0.3ml/min

-sample concentration: 2.0mg/ml

-injection amount: 10 μ l

Column temperature: 40 deg.C

-a detector: RI detector (Agilent Co.)

-standard: polystyrene (calibrated by cubic function)

-data processing: ChemStation

(2) Molecular weight distribution

The calculation is carried out by "weight average molecular weight/number average molecular weight".

[ Table 2]

	Conversion (%)	Number average molecular weight	Weight average molecular weight	Molecular weight distribution
					Example 1	>99	3200	5300	1.6
Example 2	>99	3300	5500	1.6
					Example 3	88	3100	4900	1.6
Example 4	>99	2100	3600	1.6
					Example 5	>99	2100	3300	1.7
Comparative example 1	80	3700	5900	1.6
					Comparative example 2	31	4300	6500	1.5
Comparative example 3	-	-	-	-

As shown in example 1 of table 2 above, hydrocarbon resins can be produced at high conversion rates by using the catalyst of the present invention. Further, if examples 2 to 5 were examined, conversion was even further improved using a catalyst composition obtained by adding various types of additives represented by formula 2 to the catalyst composition, and a hydrocarbon resin could be produced with even better efficiency. In addition, in the case of comparative example 1 in which no additive was used, the conversion rate was less than that of the example in which an additive was used. By using this additive, the chain transfer reaction can be promoted by a nitrogen atom or an oxygen atom having an unshared electron pair which is liable to bond with a hydrogen cation.

In the case of comparative example 2 using lutidine not corresponding to formula 2, methyl groups were bonded to two carbon atoms adjacent to the nitrogen atom, it was confirmed that the bonding reaction of the nitrogen atom with the hydrogen cation was not facilitated, the chain transfer reaction was not promoted, and a very low polymerization conversion rate was exhibited.

In addition, in the case of comparative example 3 in which phenanthroline having a structure in which two nitrogen atoms can form coordinate bonds simultaneously is used, the nitrogen atoms simultaneously form coordinate bonds with the catalyst, so that the activity of the catalyst is lowered, the polymerization reaction does not proceed properly, and the hydrocarbon resin cannot be formed.