Cycloolefin copolymer and method for producing the same

Abstract

To provide a cycloolefin copolymer applicable as an agent for improving grip, stickiness, and processability in tire compounds and as an agent for imparting adhesion and water resistance in adhesives and glues, coatings, printing inks, traffic paints, and the like.SOLUTION: A cycloolefin copolymer has a softening point of 60-130°C, a bromine number of 10-60, and a number average molecular weight of 800-5,000.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a cycloolefin copolymer and a method for easily producing the cycloolefin copolymer by decomposing a cycloolefin polymer. [Background technology]

[0002] Cycloolefin polymers have excellent optical and chemical properties and are used in a wide range of applications, from optical lenses and optical films to medical and biotechnology fields.

[0003] In recent years, the importance of promoting the circulation of plastics has been increasing amid calls for the realization of carbon neutrality and for stronger responses to the problems of marine plastic waste and climate change. Cycloolefin polymers, which are used in optical materials and automotive parts, are produced in the amount of tens of thousands of tons per year, and their recycling has become an issue.

[0004] The molecular structure and physical properties of cycloolefin polymers made it possible to reuse them as tackifier resins. However, because commercially available cycloolefin polymers have a high number-average molecular weight of over 30,000, they have poor affinity with the base rubber and elastomers, and the expected performance as a tackifier resin was not realized.

[0005] It is known that a low molecular weight cycloolefin polymer having a number average molecular weight (Mn) of 10,000 to 50,000 and a molecular weight distribution dispersity (Mw / Mn) of 2.0 to 10.0 can be produced by melting a cycloolefin polymer (number average molecular weight of 30,000 or more) and pyrolyzing it at 330 to 380°C (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6083597 Summary of the Invention [Problem to be solved by the invention]

[0007] The low molecular weight cycloolefin polymer described in Patent Document 1 has poor affinity with rubber, and therefore does not exhibit mechanical properties or adhesive performance, making it unsuitable for reuse as a tackifier resin. [Means for solving the problem]

[0008] Means for Solving the Problems The present inventors have conducted intensive research to solve the above problems and have discovered that a specific cycloolefin copolymer synthesized by decomposition of a cycloolefin polymer exhibits the function of a tackifier resin, thereby completing the present invention.

[0009] That is, the respective aspects of the present invention are as follows [1] to [4]. [1] A cycloolefin copolymer having a softening point of 60 to 130°C, a bromine number of 10 to 60, and a number average molecular weight of 800 to 5,000. [2] The cycloolefin copolymer according to [1], which contains a cycloalkene having a norbornene skeleton and a non-cyclic monoolefin as constituent monomers. [3] The cycloolefin copolymer according to [1] or [2], which has a softening point of 80 to 120°C. [4] A method for producing a cycloolefin copolymer, comprising melting a cycloolefin polymer containing a cycloalkene having a norbornene skeleton and a non-cyclic monoolefin as constituent monomers, and pyrolyzing the polymer at 300 to 450°C. Effect of the Invention

[0010] According to the present invention, there can be provided a cycloolefin copolymer which can be used as an agent for improving the grip property, adhesion and processability of tire compounds, as a tackifier and a water resistance imparting agent for adhesives, paints, printing inks, traffic paints, etc. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below.

[0012] The cycloolefin copolymer according to one embodiment of the present invention has a softening point of 60 to 130° C., a bromine number of 10 to 60, and a number average molecular weight of 800 to 5,000.

[0013] The above cycloolefin copolymers can be used as grip, adhesion and processability improvers for tire compounds, and as tackifiers and water resistance improvers for adhesives, paints, printing inks, traffic paints, etc. Hereinafter, rubber, polyolefin, petroleum resin, vegetable oil, etc., which are blended with cycloolefin copolymers, are referred to as the base material.

[0014] The softening point of the cycloolefin copolymer is preferably 60 to 130° C., more preferably 80 to 120° C., in accordance with JIS K-2207, since this provides excellent compatibility with the base resin and processability.

[0015] The cycloolefin copolymer may contain a carbon-carbon double bond. As an index of this, the bromine number measured according to JIS K-2605 (1996) is 10 to 60 (g-Br2 / 100g). If the bromine number is 60 or less, the cycloolefin copolymer has excellent heat resistance and is less likely to develop coloration due to thermal decomposition.

[0016] The number average molecular weight of the cycloolefin copolymer is 800 to 5000, and preferably 800 to 3000. If the number average molecular weight is within this range, compatibility with rubber is good when rubber is used as the base resin.

[0017] The cycloolefin copolymer is preferably a copolymer containing a cycloalkene having a norbornene skeleton and a non-cyclic monoolefin as constituent monomers.

[0018] Examples of the cycloalkene having a norbornene skeleton include monocycloalkenes having 7 to 25 carbon atoms and a norbornene skeleton {norbornene (bicyclo[2.2.1]-2-heptene), tricyclo[4.3.0.1 2,5]-3-decene, 8-ethyl-tetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene, tricyclo[4.3.0.1 2,5 ]-3-decene, tetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene, pentacyclo[6.5.1.1 3,6 .0 2,7 .0 9,13 ]-4-Pentadecene, Pentacyclo[7.4.0.1 2,5 .1 9,12 .0 8,13 ]-3-Pentadecene, Pentacyclo[8.4.0.1 2,5 .1 9,12 .0 8,13 ]-3-Hexadecene, Pentacyclo[6.6.1.1 3,6 .0 2,7 .0 9,14 ]-4-Hexadecene, Hexacyclo[6.6.1.1 3,6 .1 10,13 .0 2,7 .0 9,14 ]-4-Heptadecene, Hexacyclo[6.6.1.1 3,6 .1 10,13 .0 2,7 .0 9,14 ]-4-Heptadecene, Heptacyclo[8.7.0.1 2,9 .1 4,7 .1 11,17 .0 3,8 .0 12,16 ]-5-Eicosene, heptacyclo[8.7.0.1 3,6 .1 10,17 .1 12,15 .0 2,7 .0 11,16 ]-4-Eicosene, heptacyclo[8.7.0.1 3,6 .1 10,17 .1 12,15 .0 2,7 .0 11,16 ]-4-Eicosene, heptacyclo[8.8.0.1 2,9 .1 4,7 .1 11,18 .0 3,8 .0 12,17 ]-5-Henneicosene, Octacyclo[8.8.0.12,9 .1 4,7 .1 11,18 .1 13,16 .0 3,8 .0 12,17 ]-5-docosene, and nonacyclo[10.9.1.1 4,7 .1 13,20 .1 15,18 .0 2,10 .0 3,8 .0 12,21 .0 14,19 ]-5-pentacosene.

[0019] Among the above cycloalkenes having a norbornene skeleton, preferred are tricyclo[4.3.0.1 2,5 ]-3-decene, 8-ethyl-tetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene, tetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene, norbornene (bicyclo[2.2.1]-2-heptene).

[0020] The acyclic monoolefin is preferably acyclic monoolefin having 2 to 10 carbon atoms. Among the acyclic monoolefins having 2 to 10 carbon atoms, those having 4 or more carbon atoms are acyclic monoolefins having a double bond at the terminal. Examples of these acyclic monoolefins include ethylene, propylene, and α-olefins having 4 to 8 carbon atoms (1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, etc.). Among these, ethylene and propylene are preferred.

[0021] The molar ratio of the cycloalkene having a norbornene skeleton to the non-cyclic monoolefin constituting the cycloolefin copolymer [cycloalkene / olefin] varies depending on the target resin, but is preferably 2 / 98 to 50 / 50, more preferably 5 / 95 to 40 / 60, and particularly preferably 10 / 90 to 30 / 70.

[0022] A method for producing a cycloolefin copolymer according to one embodiment of the present invention is a method for producing a cycloolefin copolymer by melting a cycloolefin polymer containing a cycloalkene having a norbornene skeleton and a non-cyclic monoolefin as constituent monomers, and thermally decomposing the cycloolefin polymer at 300 to 450°C.

[0023] A preferred method for adjusting the cycloolefin copolymer to have the above number average molecular weight is to reduce the molecular weight by subjecting the cycloolefin polymer to a thermal decomposition reaction to partially cleavage of the main chain.

[0024] The cycloolefin polymer can be any cycloolefin polymer having a number average molecular weight of 10,000 to 200,000, which is composed of the cycloalkene having a norbornene skeleton and the acyclic monoolefin, and is not limited thereto. Commercially available products (e.g., Zeonex series and Zeonor series manufactured by Zeon Corporation, Apel series manufactured by Mitsui Chemicals, Inc., and TOPAS series manufactured by Polyplastics Co., Ltd.) may also be used.

[0025] The pyrolysis is preferably carried out in an atmosphere of a gas that is not reactive with the cycloolefin polymer (hereinafter referred to as an inert gas) at 300 to 450°C for 0.5 to 10 hours. Specific examples of the inert gas include argon, nitrogen, carbon dioxide, and water vapor, and nitrogen is preferred. The inert gas is preferably passed through the reaction vessel at a flow rate of 0.1 to 100 L / min during heating.

[0026] The heating temperature is preferably 300 to 450° C., more preferably 320 to 450° C. When the reaction temperature is within this range, the coloring of the cycloolefin copolymer is reduced and the generation of odor is suppressed, which is preferable. Hereinafter, the fact that the coloring is reduced and the generation of odor is suppressed is referred to as "good color tone and odor."

[0027] The reaction time is preferably 0.5 to 10 hours, more preferably 1 to 7 hours. When the reaction time is within this range, the color and odor of the unsaturated bond-containing cycloolefin copolymer become good, and homogeneous thermal decomposition can be achieved, which is preferable.

[0028] The pressure for pyrolysis is between normal pressure (atmospheric pressure) and 200 kg / cm 2 is preferable, and more preferably from normal pressure to 150 kg / cm 2 Within this range, the color tone and odor of the unsaturated bond-containing cycloolefin copolymer will be good.

[0029] The thermal decomposition method may be either a batch method or a continuous method. When using a batch method, the process can be carried out by passing an inert gas through a reaction vessel made of stainless steel or the like equipped with a stirrer, placing the raw material cycloolefin polymer in the reaction vessel, and heating the reaction vessel at a predetermined temperature for a predetermined period of time while stirring.

[0030] When a continuous process is used, an inert gas is passed through a continuous reaction vessel such as a tubular reactor or an extruder, the raw material cycloolefin polymer is placed in the reaction vessel, and the raw material is heated and melted while adjusting the amount of the raw material introduced so that the raw material remains in the reaction vessel at a predetermined temperature for a predetermined time, thereby carrying out thermal decomposition.

[0031] The thermal decomposition may be carried out by adding a phenol-based antioxidant. Examples of the phenol-based antioxidant include hindered phenol compounds such as 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4-methylphenol, 6-tert-butyl-2,4-methylphenol, 2,6-di-tert-butylphenol, and 2-tert-butyl-4-ethylphenol.

[0032] In the thermal decomposition, a catalyst can be used to promote the decomposition reaction. Examples of the catalyst to be added include radical generating catalysts [peroxides such as benzoyl peroxide, di-tert-butyl peroxide, and dicumyl peroxide; azonitriles such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 4,4'-azobis(4-cyanovaleric acid)] and cracking catalysts (silica-alumina, silica-magnesia, activated clay, etc.). EXAMPLES

[0033] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The analytical and test methods used in the examples and comparative examples are as follows.

[0034] The analytical methods for cycloolefin copolymers are shown below.

[0035] ~Measurement of weight average molecular weight (Mw) and number average molecular weight (Mw)~ Polystyrene was used as the standard substance and measurements were performed by gel permeation chromatography in accordance with JIS K-0124 (2011).

[0036] ~Bromine number~ The measurement was performed according to a method conforming to JIS K-2605 (1996).

[0037] ~Softening point~ The measurement was performed according to JIS K-2207 (1996) (Ball and Ring Method).

[0038] Example 1 A small quartz pyrolysis device was used as the pyrolysis device. 10 g of cycloolefin polymer (ZEON Corporation, ZEONEX690R, Mn 15,000) was charged into the pyrolysis device, and after replacing the inside of the system with nitrogen, it was heated and melted at an internal temperature of 350°C. After 60 minutes, it was cooled to room temperature, and the reaction system was returned to normal pressure. The residue in the pyrolysis device was dissolved in hot xylene, and then dropped into methanol for reprecipitation and purification to produce a cycloolefin copolymer. The evaluation results are shown in Table 1.

[0039] Examples 2 to 3, Comparative Example 1 A cycloolefin copolymer was produced in the same manner as in Production Example 1, except that the pyrolysis conditions (temperature, time) and the type of cycloolefin polymer were as shown in Table 1. The evaluation results are shown in Table 1. TOPAS6013M-07 (Mn 50,000) is a cycloolefin polymer manufactured by Polyplastics Co., Ltd.

[0040] [Table 1]

[0041] ~Tire compound evaluation~ In a Banbury mixer (volume 1.7 liters), 55 parts by mass of natural rubber (RSS#3) and 45 parts by mass of solution polymerized terminal modified styrene-butadiene copolymer rubber (modified S-SBR) (manufactured by JSR Corporation, (trade name) HPR-350) were blended and masticated for 30 seconds to obtain a total of 100 parts by mass of rubber components. Then, 2 parts by mass of stearic acid (manufactured by New Japan Chemical Co., Ltd.), 70 parts by mass of silica (manufactured by Tosoh Silica, (trade name) Nipsil AQ), 5.6 parts by mass of a silane coupling agent (manufactured by Shin-Etsu Silicone, (trade name) KBE46), and 20 parts by mass of the cycloolefin copolymer A obtained in Example 1 were added to the total of 100 parts by mass of rubber components, and the total kneading time was 5 minutes, after which the mixture was taken out. The ram pressure and rotation speed were adjusted so that the compound temperature at the time of taking out was 140°C to 150°C. The obtained compound was cooled to room temperature, and then 1 part by mass of an antioxidant (manufactured by Ouchi Shinko, product name: 810NA), 3 parts by mass of zinc oxide (manufactured by Inoue Lime Industry), 1.2 parts by mass of a vulcanization accelerator (1) (manufactured by Ouchi Shinko, product name: Noccela CZ), 1.5 parts by mass of a vulcanization accelerator (2) (manufactured by Ouchi Shinko, product name: Noccela D), and 1.5 parts by mass of sulfur (manufactured by Tsurumi Chemical Industry) as a vulcanizing agent were added and kneaded for about 1 minute (the temperature at the time of removal was 110°C or less), and then sheeted using an 8-inch roll to obtain an unvulcanized rubber composition.

[0042] The rubber composition was then vulcanized at a temperature of 150°C for 30 minutes using a steam heating press to obtain a vulcanized rubber composition. The properties of the vulcanized rubber composition (wet grip, rolling resistance, abrasion resistance) were measured according to the following methods. The results are shown in Table 1.

[0043] Similar tire compound evaluations were also carried out for Examples 2 and 3 and Comparative Example 1. The results are shown in Table 1.

[0044] ~Wet grip~ Using a viscoelasticity measuring device (manufactured by Rheometrics), tan δ was measured at a temperature of 0° C., a strain of 5%, and a frequency of 15 Hz, and the value at 0° C. was evaluated as wet grip performance.

[0045] When tan δ at 0° C. was 0.27 or more, the wet grip performance was determined to be good.

[0046] ~Rolling resistance~ Using a viscoelasticity measuring device (manufactured by Rheometrics), tan δ was measured at a temperature of 60° C., a strain of 5%, and a frequency of 15 Hz, and the value at 60° C. was evaluated as the rolling resistance.

[0047] When tan δ at 60° C. was 0.14 or less, the rolling resistance was determined to be good.

[0048] ~Abrasion resistance~ Vulcanized rubber test pieces were prepared, and the amount of wear was measured at 23° C. using a Lambourn abrasion tester in accordance with JIS K-6264.

[0049] Wear at 23℃ is 24mm 3 / min or less, the abrasion resistance was determined to be good. [Industrial Applicability]

[0050] According to the present invention, the cycloolefin copolymer can be used as an agent for improving the grip, adhesion and processability of tire compounds, a tackifier for adhesives, paints, printing inks, traffic paints, etc., and a water resistance imparting agent.

Claims

1. A cycloolefin copolymer having a softening point of 60 to 130° C., a bromine number of 10 to 60, and a number average molecular weight of 800 to 5,000.

2. 2. The cycloolefin copolymer according to claim 1, which comprises a cycloalkene having a norbornene skeleton and a non-cyclic monoolefin as constituent monomers.

3. 3. The cycloolefin copolymer according to claim 1 or 2, having a softening point of 80 to 120°C.

4. A method for producing a cycloolefin copolymer, comprising melting a cycloolefin polymer containing a cycloalkene having a norbornene skeleton and a non-cyclic monoolefin as constituent monomers, and pyrolyzing the polymer at 300 to 450°C.

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