JP2023112592A - Resin composition for injection molding and injection molded body - Google Patents

Abstract

To provide a resin composition for injection molding comprising a cyclic olefin copolymer which gives an injection moded body which has excellent breaking strain and toughness and having hardly causes cracks even when placed in a high temperature and high humidity environment and to provide an injection molded body comprising the resin composition for injection molding.SOLUTION: There is provided a resin composition for injection molding comprising (A) a cyclic olefin copolymer and a specific amount of (B) a hindered phenol-based antioxidant, wherein the amount of the structural unit derived from the α-olefin is adjusted to be 10 mol% or more and 40 mol% or less based on the total structural units and the cyclic olefin copolymer (A) is adjusted to have two or more glass transition temperatures in the range of 0°C to 300°C as determined by solid viscoelasticity measurement in the cyclic olefin copolymer (A) by using a copolymer of a cyclic olefin monomer and an α-olefin having 3 or more and 20 or less carbon atoms as the cyclic olefin copolymer (A).SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to an injection-molding resin composition containing a cyclic olefin copolymer and an injection-molded article.

Cyclic olefin polymers and cyclic olefin copolymers (also called “COP” and “COC”, etc., respectively) have low hygroscopicity and high transparency. Therefore, COPs and COCs are used in various applications, including the field of optical materials such as optical disk substrates, optical films, and optical fibers. A typical COC is a copolymer of cyclic olefin and ethylene. The glass transition temperature of such a copolymer can be changed by the copolymer composition of the cyclic olefin and ethylene. Therefore, a copolymer of cyclic olefin and ethylene can be produced as a copolymer with a higher glass transition temperature (Tg) than COP, and it is also possible to achieve a Tg of over 200°C, which is difficult with COP. be. However, such copolymers have a hard and brittle character. Therefore, such copolymers have problems of low mechanical strength and poor handling and workability.

One of the methods for improving the mechanical strength of high TgCOC is a method of copolymerizing a cyclic olefin and an α-olefin other than ethylene (hereinafter referred to as "specific α-olefin"). Various studies have been made on the copolymerization of cyclic olefins and specific α-olefins.

Copolymerization of cyclic olefins with specific α-olefins is significantly different from copolymerization of cyclic olefins with ethylene. Under the conditions under which a high molecular weight product can be obtained by copolymerizing a cyclic olefin and ethylene, a chain transfer reaction caused by the specific α-olefin occurs in the copolymerization of the cyclic olefin and the specific α-olefin. was difficult to obtain. Therefore, copolymers of cyclic olefins and specific α-olefins have been considered unsuitable for molding materials (see, for example, Non-Patent Document 1).

Therefore, various investigations have been made to improve the moldability of copolymers of cyclic olefins and specific α-olefins. For example, as a method for producing a copolymer of a cyclic olefin and a specific α-olefin having a relatively high molecular weight and capable of being formed into a film, a titanocene catalyst having a specific structure and triphenylmethylium tetrakis(pentafluorophenyl)borate A method has been proposed in which a cyclic olefin and a specific α-olefin are copolymerized in the presence of (see Patent Document 1).

JP 2016-56275 A

Jung, H.; Y. et al., Polyhedron, 2005, vol. 24, p. 1269-1273

However, even if injection molding is performed using a copolymer of a cyclic olefin and a specific α-olefin obtained by the method described in Patent Document 1, an injection molded article having both excellent breaking strain and toughness can be obtained. Otherwise, when the resulting injection molded article is placed in a high temperature and high humidity environment, the injection molded article tends to crack.

The present invention has been made in view of the above circumstances, and provides an injection-molded article that has both excellent breaking strain and excellent toughness, and is resistant to cracking even when placed in a high-temperature, high-humidity environment. An object of the present invention is to provide an injection-molding resin composition containing a cyclic olefin copolymer, and an injection-molded article made of the injection-molding resin composition.

The present inventors found that in an injection molding resin composition containing (A) a cyclic olefin copolymer and a specific amount of (B) a hindered phenol-based antioxidant, (A) the cyclic olefin copolymer, Using a copolymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms, (A) the amount of structural units derived from the α-olefin in the cyclic olefin copolymer is added to all structural units 10 mol % or more and 40 mol % or less, and (A) the cyclic olefin copolymer has two or more glass transition temperatures determined by solid viscoelasticity measurement within the range of 0 ° C. to 300 ° C. As a result, the inventors have found that the above problems can be solved, and have completed the present invention. More specifically, the present invention provides the following.

(I) A resin composition for injection molding comprising (A) a cyclic olefin copolymer and (B) a hindered phenolic antioxidant,
(A) The cyclic olefin copolymer is a cyclic olefin copolymer that is an addition-type polymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms,
(A) the ratio of the number of moles of structural units derived from an α-olefin to the number of moles of all structural units of the cyclic olefin copolymer is 10 mol% or more and 40 mol% or less;
(A) the cyclic olefin copolymer has two or more glass transition temperatures within the range of 0° C. to 300° C. by viscoelasticity measurement;
(B) A resin composition for injection molding, wherein the content of the hindered phenolic antioxidant is 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the (A) cyclic olefin copolymer.

(II) The cyclic olefin copolymer according to (I), wherein (A) has at least one glass transition temperature within the range of 0°C to 100°C and within the range of 160°C to 300°C. A resin composition for injection molding.

(III) (A) The cyclic olefin copolymer has at least one glass transition temperature in the range of less than 0°C, in the range of 0°C to 100°C, and in the range of 160°C to 300°C. The resin composition for injection molding according to (I) or (II).

(VI) An injection-molded article comprising the resin composition for injection molding according to any one of (I) to (III).

(V) The injection molded article according to (VI), which has a tensile strength of 30 MPa or more and a tensile breaking strain of 8% or more, as measured according to ISO527-1.

INDUSTRIAL APPLICABILITY According to the present invention, an injection-molded article containing a cyclic olefin copolymer that has both excellent breaking strain and excellent toughness and that is resistant to cracking even when placed in a high-temperature, high-humidity environment is provided. A resin composition and an injection molded article made of the resin composition for injection molding can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment.

<<Resin composition for injection molding>>
The resin composition for injection molding contains (A) a cyclic olefin copolymer and (B) a hindered phenolic antioxidant.
The content of (B) the hindered phenolic antioxidant in the resin composition for injection molding is 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the (A) cyclic olefin copolymer.
By using the above resin composition for injection molding, it is possible to obtain an injection-molded article that has both excellent breaking strain and excellent toughness, and is less likely to crack even when placed in a high-temperature, high-humidity environment.

The essential or optional components contained in the injection molding resin composition are described below.

<(A) Cyclic olefin copolymer>
(A) The cyclic olefin copolymer is an addition type polymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms. (A) In the cyclic olefin copolymer, the ratio of the number of moles of structural units derived from α-olefin to the number of moles of all structural units is 10 mol % or more and 40 mol % or less. In addition, (A) the cyclic olefin copolymer has two or more glass transition temperatures within the range of 0° C. to 300° C. by viscoelasticity measurement.

Although the detailed mechanism is unknown, the above (A) cyclic olefin copolymer has both excellent breaking strain and excellent toughness.
Specifically, the (A) cyclic olefin copolymer is measured by a tensile test using a 1BA dumbbell test piece with a thickness of 2 mm at 23 ° C. according to the method in accordance with ISO 527-1. It exhibits a tensile strength of preferably 25 MPa or more, more preferably 27.5 MPa or more, and still more preferably 30 MPa or more.
In addition, (A) the cyclic olefin copolymer exhibits a tensile breaking strain of preferably 4% or more, more preferably 6% or more, and even more preferably 8% or more as a measured value in a tensile test according to the above method.
Furthermore, (A) the cyclic olefin copolymer exhibits a tensile modulus of preferably 1000 MPa or more, more preferably 1100 MPa or more, and even more preferably 1500 MPa or more as a measured value by a tensile test according to the above method.

(A) In the cyclic olefin copolymer, the ratio of the number of moles of structural units derived from α-olefin to the number of moles of all structural units is 10 mol% or more and 40 mol% or less, and 20 mol% or more and 30 mol%. The following are preferred. If the molar ratio of structural units derived from α-olefin is too high, it is difficult to obtain (A) a cyclic olefin copolymer with high tensile strength and tensile elastic modulus. If the molar ratio of structural units derived from α-olefin is too high, it is difficult to obtain (A) a cyclic olefin copolymer that has a high glass transition temperature and excellent heat resistance.
The molar ratio of structural units derived from α-olefin can be calculated by measuring ¹³ C-NMR spectrum.

(A) The cyclic olefin copolymer is a structural unit derived from a cyclic olefin monomer and a structural unit other than a structural unit derived from an α-olefin having 3 to 20 carbon atoms within a range that does not hinder the object of the present invention. It may contain a structural unit. As other structural units, a structural unit derived from a compound having a carbon-carbon unsaturated double bond, which is copolymerizable with a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms, is employed. obtain. Structural units derived from ethylene are typically preferred as other structural units.

(A) In the cyclic olefin copolymer, the sum of the ratio of the number of moles of the structural unit derived from the cyclic olefin monomer and the ratio of the number of moles of the structural unit derived from the α-olefin to the number of moles of all structural units is , is preferably 80 mol % or more, more preferably 90 mol % or more, still more preferably 95 mol % or more, and most preferably 100 mol %.

(A) The cyclic olefin copolymer has two or more glass transition temperatures within the range of 0° C. to 300° C. by viscoelasticity measurement.
The glass transition temperature can be measured by observing the viscoelastic behavior at −100° C. to 300° C. with a solid rheometer using a film-like molded product with a thickness of 50 μm. Specifically, regarding the peaks in the tan δ chart obtained by the above measurement, the peak top temperature is taken as the glass transition temperature.

Since the mechanical properties measured by the above tensile test are good, the (A) cyclic olefin copolymer is in the range of 0 ° C. to 100 ° C. and in the range of 160 ° C. to 300 ° C., respectively. It preferably has at least one glass transition temperature.
In particular, since the breaking strain measured by the above tensile test is large, the (A) cyclic olefin copolymer is in the range of less than 0 ° C., in the range of 0 ° C. to 100 ° C. preferably have at least one glass transition temperature within the range of and respectively.
Within the above range of 0°C to 100°C, the range of 30°C to 80°C is preferred, and the range of 40°C to 70°C is more preferred.
Within the above range of 160°C to 300°C, 170°C to 280°C is preferred, and 180°C to 270°C is more preferred.
Within the above range of less than 0°C, -50°C to 0°C is preferred, and -40°C to -10°C is more preferred.

Typically, (A) the cyclic olefin copolymer has one glass transition temperature in the range of 0° C. to 100° C. and one in the range of 160° C. to 300° C., or less than 0° C. , 0° C. to 100° C., and 160° C. to 300° C., respectively.

(A) The molecular weight of the cyclic olefin copolymer is not particularly limited. (A) The weight average molecular weight (Mw) of the cyclic olefin copolymer is preferably 5,000 or more and 200,000 or less, more preferably 10,000 or more, as a polystyrene-equivalent value measured by gel permeation chromatography (GPC). 100,000 or less is more preferable.
(A) The number average molecular weight (Mn) of the cyclic olefin copolymer is preferably 5,000 or more and 200,000 or less, preferably 10,000 or more, as a value in terms of polystyrene measured by gel permeation chromatography (GPC). 100,000 or less is more preferable.
The dispersion ratio (Mw/Mn) is preferably 1.2 or more, more preferably 1.3 or more.

[Cyclic olefin monomer]
The cyclic olefin monomer is not particularly limited as long as it does not impair the object of the present invention. Typically, norbornene and substituted norbornenes are preferably used as cyclic olefin monomers. As the cyclic olefin monomer, norbornene is particularly preferred from the viewpoint of a good balance of cost, polymerizability, and physical properties of the resulting cyclic olefin copolymer (A). A cyclic olefin monomer can be used individually by 1 type or in combination of 2 or more types.

Substituted norbornenes are not particularly limited. Substituents possessed by substituted norbornene include, for example, halogen atoms and monovalent or divalent hydrocarbon groups. Specific examples of substituted norbornenes include compounds represented by the following formula (I).

In formula (I), R ^a1 to R ^a12 , which may be the same or different, are atoms or groups selected from the group consisting of a hydrogen atom, a halogen atom and a hydrocarbon group.
R ^a9 and R ^a10 and R ^a11 and R ¹² may combine to form a divalent hydrocarbon group.
R ^a9 or R ^a10 and R ^a11 or R ^a12 may combine with each other to form a ring.
n is 0 or a positive integer.
When n is 2 or more, R ^a5 to R ^a8 may be the same or different in each repeating unit.
However, when n is 0, at least one of R ^a1 to R ^a4 and R ^a9 to R ^a12 is not a hydrogen atom.

Specific examples of R ^a1 to R ^a8 include, for example, a hydrogen atom; a halogen atom such as fluorine, chlorine, and bromine; and an alkyl group having 1 to 20 carbon atoms. R ^a1 to R ^a8 may all consist of different atoms or groups. Some or all of R ^a1 to R ^a8 may be the same atoms or groups.

Specific examples of R ^a9 to R ^a12 include, for example, a hydrogen atom; a halogen atom such as fluorine, chlorine, and bromine; an alkyl group having 1 to 20 carbon atoms; a cycloalkyl group such as a cyclohexyl group; substituted or unsubstituted aromatic hydrocarbon groups such as ethylphenyl group, isopropylphenyl group, naphthyl group and anthryl group; aralkyl groups such as benzyl group and phenethyl group; R ^a9 to R ^a12 may all consist of different atoms or groups. Some or all of R ^a9 to R ^a12 may be the same atoms or groups.

Specific examples of the divalent hydrocarbon group that can be formed by combining R ^a9 and R ^a10 or R ^a11 and R ^a12 are alkylidene groups such as ethylidene group, propylidene group, and isopropylidene group. etc.

When R ^a9 or R ^a10 and R ^a11 or R ^a12 are combined to form a ring, the ring formed may be monocyclic or polycyclic. The rings formed may be polycyclic with bridges. The ring formed may have a double bond. The formed ring may have a substituent such as a methyl group.

Specific examples of substituted norbornenes represented by formula (I) include 5-methyl-bicyclo[2.2.1]hept-2-ene, 5,5-dimethyl-bicyclo[2.2.1]hept-2 -ene, 5-ethyl-bicyclo[2.2.1]hept-2-ene, 5-butyl-bicyclo[2.2.1]hept-2-ene, 5-ethylidene-bicyclo[2.2.1 ]hept-2-ene, 5-hexyl-bicyclo[2.2.1]hept-2-ene, 5-octyl-bicyclo[2.2.1]hept-2-ene, 5-octadecyl-bicyclo[2 .2.1]hept-2-ene, 5-methylidene-bicyclo[2.2.1]hept-2-ene, 5-vinyl-bicyclo[2.2.1]hept-2-ene, 5-propenyl - bicyclic cyclic olefins such as bicyclo[2.2.1]hept-2-ene;
tricyclo[4.3.0.1 ^2,5 ]deca-3,7-diene (common name: dicyclopentadiene), tricyclo[4.3.0.1 ^2,5 ]dec-3-ene; tricyclo[ 4.4.0.1 ^2,5 ]undeca-3,7-diene or tricyclo[4.4.0.1 ^2,5 ]undeca-3,8-diene or partially hydrogenated products thereof (or cyclopentadiene and cyclohexene) which are tricyclo[4.4.0.1 ^2,5 ]undec-3-ene; 5-cyclopentyl-bicyclo[2.2.1]hept-2-ene, 5-cyclohexyl-bicyclo 3 such as [2.2.1]hept-2-ene, 5-cyclohexenylbicyclo[2.2.1]hept-2-ene, 5-phenyl-bicyclo[2.2.1]hept-2-ene cyclic olefins of the ring;
Tetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene (also referred to simply as tetracyclododecene), 8-methyltetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-ethyltetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-methylidenetetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-ethylidenetetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-vinyltetracyclo[4,4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-propenyl-tetracyclo[4.4.0.1 ^2,5 . 4-ring cyclic olefins such as 1 ^7,10 ]dodeca-3-ene;
8-Cyclopentyl-tetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-cyclohexyl-tetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-cyclohexenyl-tetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene, 8-phenyl-cyclopentyl-tetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]dodeca-3-ene; tetracyclo[7.4.1 ^3,6 . 0 ^{1, 9} . 0 ^2,7 ]tetradeca-4,9,11,13-tetraene (also called 1,4-methano-1,4,4a,9a-tetrahydrofluorene), tetracyclo[8.4.1 ^4,7 . 0 ^{1, 10} . 0 ^3,8 ]pentadeca-5,10,12,14-tetraene (also known as 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene); pentacyclo[6.6.1 .1 ^{3, 6} . 0 ^{2, 7} . 0 ^9,14 ]-4-hexadecene, pentacyclo[6.5.1.1 ^3,6 . 0 ^{2, 7} . 0 ^9,13 ]-4-pentadecene, pentacyclo[7.4.0.0 ^2,7 . 1 ^{3, 6} . 1 ^10,13 ]-4-pentadecene; 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 ^2,9 . 0 ^{3, 8} . 1 ^{4, 7} . 0 ^{12, 17} . 1 ^13,16 ]-14-eicosene; and polycyclic cyclic olefins such as tetramer of cyclopentadiene.

Among these, for example, alkyl-substituted norbornenes such as bicyclo[2.2.1]hept-2-ene substituted with one or more alkyl groups, bicyclo[2.2.1]hept-2-ene Preferred are alkylidene-substituted norbornenes substituted with one or more alkylidene groups such as. 5-ethylidene-bicyclo[2.2.1]hept-2-ene (common name: 5-ethylidene-2-norbornene, or simply ethylidenenorbornene) is particularly preferred.

[α-olefin]
The α-olefin is an α-olefin having 3 to 20 carbon atoms.
As such α-olefins, not only unsubstituted α-olefins but also substituted α-olefins having substituents such as halogen atoms can be used. The number of carbon atoms in the α-olefin is 3 or more and 20 or less, preferably 4 or more and 12 or less, and more preferably 6 or more and 10 or less.

Specific examples of α-olefins having 3 to 12 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3- to ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1- xene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene and the like. Among these, 1-hexene, 1-octene and 1-decene are preferred.

（式（１）中、Ｒ^１～Ｒ^３は、それぞれ独立に、炭素原子数１以上６以下のアルキル基又は炭素原子数６以上１２以下のアリール基であり、Ｒ^４及びＲ^５は、それぞれ独立に、炭素原子数１以上１２以下のアルキル基、炭素原子数６以上１２以下のアリール基、又はハロゲン原子であり、Ｒ^６～Ｒ^１３は、それぞれ独立に、水素原子、炭素原子数１以上１２以下のアルキル基、炭素原子数６以上１２以下のアリール基、又は炭素原子数１以上１２以下の１価の炭化水素基を置換基として有していてもよいシリル基である。） [Method for producing (A) cyclic olefin copolymer]
Hereinafter, the method for producing the aforementioned (A) cyclic olefin copolymer will be described.
(A) A method for producing a cyclic olefin copolymer includes addition polymerization of a cyclic olefin monomer and an α-olefin in the presence of a titanocene catalyst represented by the following formula (1) and a cocatalyst. . Promoters include borate compounds and hindered phenols.
In the above-described production method, the cyclic olefin monomer and the α-olefin are separately added to the reaction system in which the addition polymerization is carried out in two or more portions.

(In Formula (1), R ¹ to R ³ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and R ⁴ and R ⁵ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom; and R ⁶ to R ¹³ each independently represent a hydrogen atom or 1 or more carbon atoms an alkyl group of 12 or less, an aryl group of 6 or more and 12 or less carbon atoms, or a silyl group optionally having a monovalent hydrocarbon group of 1 or more and 12 or less carbon atoms as a substituent.)

According to this method, it is possible to provide (A) a cyclic olefin copolymer that satisfies the constituent requirements described in any one of (I) to (III) above. This method below is also referred to as "first manufacturing method".

The following production method is also preferable as the production method of (A) the cyclic olefin copolymer. According to this method, (A) a cyclic olefin copolymer that satisfies the structural requirements described in (I) or (II) above can be provided.
Specifically, this method includes addition polymerization of a cyclic olefin monomer and an α-olefin in the presence of a titanocene catalyst represented by formula (1) and a cocatalyst. Promoters include borate compounds and hindered phenols. The addition polymerization is carried out at a temperature within the range of 10°C or higher and 60°C or lower. For the titanocene catalyst represented by Formula (1), the first production method is the same as the titanocene catalyst described above.
Hereinafter, this method is also referred to as "second manufacturing method".

(First manufacturing method)
In the first production method, a monomer containing the aforementioned cyclic olefin monomer and an α-olefin is used. The type of cyclic olefin monomer, the type of α-olefin, and the copolymerization ratio thereof are as described for (A) the cyclic olefin copolymer.

In the first production method, the cyclic olefin monomer and the α-olefin are separately added to the reaction system in which the addition polymerization is carried out in two or more steps.
Thus, by adding a cyclic olefin monomer and an α-olefin, it is easy to obtain (A) a cyclic olefin copolymer having good mechanical properties. In addition, by adding the cyclic olefin monomer and the α-olefin in this way, it is easy to obtain the (A) cyclic olefin copolymer having a glass transition temperature in the range of less than 0°C.

When dividing addition is performed, the number of divisions is not particularly limited. The number of divisions is, for example, preferably 2 or more and 5 or less, more preferably 2 or 3, and even more preferably 2.
When performing divided addition, the amount of cyclic olefin monomer or α-olefin added per time is TA / N × 0.5 or more TA, where TA is the mass of the entire addition amount and N is the number of divisions. /N×1.5 or less is preferable, TA/N×0.7 or more and TA/N×1.3 or less is more preferable, and TA/N×0.9 or more and TA/N×1.1 or less is more preferable.

When the number of divisions is two, the amount of the cyclic olefin monomer or α-olefin added per division is preferably 25% by mass or more and 75% by mass or less, and 35% by mass or more, based on the total mass of the added amount. 65% by mass or more is more preferable, and 45% by mass or more and 55% by mass or less is even more preferable.

At least one of the cyclic olefin monomer and the alpha-olefin is added to the reaction vessel at or before the initiation of the addition polymerization, if split addition is used. Then, at any timing after the initiation of the addition polymerization, the second and subsequent cyclic olefin monomers or α-olefins are added.
When performing divisional addition, the time between each addition is preferably 3 minutes or more and 20 minutes or less, more preferably 5 minutes or more and 15 minutes or less.
When performing divided addition, the timing of adding the cyclic olefin monomer and the timing of adding the α-olefin may be the same or different.
Further, the number of divided additions of the cyclic olefin monomer and the divided number of additions of the α-olefin may be different.

As described above, the titanocene catalyst represented by the above formula (1) is used when producing the (A) cyclic olefin copolymer.
In Formula (1), R ¹ to R ³ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. Specific examples thereof include alkyl groups such as a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, cyclopentyl group and cyclohexyl group; phenyl group and biphenyl group; , a phenyl group or biphenyl group having the above alkyl group as a substituent, a naphthyl group, and an aryl group such as a naphthyl group having the above alkyl group as a substituent.

R ⁴ and R ⁵ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. Halogen atoms such as bromine and iodine atoms; methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, cyclohexyl groups , these alkyl groups having the above halogen atoms as substituents; phenyl groups, biphenyl groups, naphthyl groups, and these aryl groups having the above halogen atoms or alkyl groups as substituents.

R ⁶ to R ¹³ each independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a monovalent hydrocarbon group having 1 to 12 carbon atoms. is a silyl group optionally having as a substituent. Specific examples of alkyl groups having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group and octyl group. , a cyclopentyl group, a cyclohexyl group, and the like. Further, specific examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a biphenyl group, a naphthyl group, and those aryl groups having the alkyl group as a substituent. Furthermore, specific examples of the silyl group having a monovalent hydrocarbon group having 1 to 12 carbon atoms as a substituent include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group and t-butyl group. , a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, and the like, having 1 to 12 carbon atoms as a substituent.

Specific examples of the titanocene catalyst represented by the general formula (1) include (isopropylamido)dimethyl-9-fluorenylsilanetitaniumdimethyl, (isobutylamido)dimethyl-9-fluorenylsilanetitaniumdimethyl, (t-butylamide) ) dimethyl-9-fluorenylsilanetitanium dimethyl, (isopropylamido)dimethyl-9-fluorenylsilanetitanium dichloride, (isobutylamido)dimethyl-9-(3,6-dimethylfluorenyl)silanetitanium dichloride, ( t-butylamido)dimethyl-9-fluorenylsilanetitanium dichloride, (isopropylamido)dimethyl-9-(3,6-dimethylfluorenyl)silanetitanium dichloride, (isobutylamido)dimethyl-9-(3,6- dimethylfluorenyl)silanetitanium dichloride, (t-butylamido)dimethyl-9-(3,6-dimethylfluorenyl)silanetitanium dimethyl, (isopropylamido)dimethyl-9-[3,6-di(i-propyl) ) fluorenyl]silanetitanium dichloride, (isobutylamido)dimethyl-9-[3,6-di(i-propyl)fluorenyl]silanetitanium dichloride, (t-butylamido)dimethyl-9-[3,6-di(i- Propyl)fluorenyl]silanetitanium dimethyl, (isopropylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silanetitanium dichloride, (isobutylamido)dimethyl-9-[3,6-di(t- Butyl)fluorenyl]silanetitanium dichloride, (t-butylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silanetitanium dimethyl, (isopropylamido)dimethyl-9-[2,7-di(t -Butyl)fluorenyl]silanetitanium dichloride, (isobutylamido)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silanetitanium dichloride, (t-butylamido)dimethyl-9-[2,7-di( t-butyl)fluorenyl]silanetitanium dimethyl, (isopropylamido)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silanetitanium dichloride, (isobutylamido)dimethyl-9-(2,3, 6,7-tetramethylfluorenyl)silanetitanium dichloride, (t-butylamido)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silanetitanium dimethyl and the like can be mentioned. Preferred is (t-butylamido)dimethyl-9-fluorenylsilanetitanium dimethyl ((t-BuNSiMe ₂ Flu)TiMe ₂ ). (t-BuNSiMe ₂ Flu)TiMe ₂ is a titanium complex represented by the following formula (2), and can be easily synthesized, for example, based on the description in "Macromolecules, Vol. can be done.

（式中、Ｍｅはメチル基を、ｔ－Ｂｕはｔｅｒｔ－ブチル基を示す。）

(In the formula, Me represents a methyl group, and t-Bu represents a tert-butyl group.)

The amount of the titanocene catalyst used is not particularly limited as long as the addition polymerization reaction proceeds well. The amount of the titanocene catalyst used is preferably 0.001 parts by mass or more and 10 parts by mass or less, more preferably 0.01 parts by mass or more and 5 parts by mass or less, relative to the total amount of 100 parts by mass of the cyclic olefin monomer and the α-olefin. 0.1 parts by mass or more and 1 part by mass or less is more preferable.

Addition polymerization of a monomer containing a cyclic olefin monomer and an α-olefin is carried out in the coexistence of the titanocene catalyst and co-catalyst. Promoters include borate compounds and hindered phenols.
In the presence of the above-mentioned titanocene catalyst and a co-catalyst, addition polymerization is carried out so as to satisfy the above-mentioned predetermined conditions, whereby (A) a cyclic olefin copolymer having both excellent breaking strain and excellent toughness is obtained. can get.

As the borate compound, any borate compound conventionally used as a co-catalyst in the homopolymerization or copolymerization of cyclic olefin monomers can be used without particular limitation. Preferred specific examples of borate compounds include triphenylmethylium tetrakis(pentafluorophenyl)borate, dimethylphenylammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, and N- Methyl di-normal decyl ammonium tetrakis(pentafluorophenyl) borate and the like can be mentioned.

As the hindered phenol, any hindered phenol that has been conventionally used as a co-catalyst in the homopolymerization or copolymerization of cyclic olefin monomers can be used without particular limitation.
Here, the hindered phenol is a phenol having a bulky substituent at at least one of the two adjacent positions of the phenolic hydroxyl group. Bulky substituents include, for example, alkyl groups other than methyl groups such as isopropyl group, isobutyl group, sec-butyl group, and tert-butyl group, alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups, and alkoxy groups. , aryloxy groups, substituted amino groups, alkylthio groups, and arylthio groups.

Specific examples of hindered phenols include 2,6-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butylphenol, 2-tert-butylphenol, 2-tert-butyl -p-cresol, 3,3',5,5'-tetra-tert-butyl-4,4'-dihydroxybiphenyl, 3,3',5,5'-tetra-tert-butyl-2,2'- Dihydroxybiphenyl, 4,4′-butylidenebis(3-methyl-6-tert-butylphenol), 2,2′-methylenebis(6-tert-butyl-4-methylphenol), 4,4′,4″-(1 -methylpropanyl-3-ylidene)tris(6-tert-butyl-m-cresol) and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)2,4 , 6-trimethylbenzene and the like.
Among these, 2,6-di-tert-butyl-4-hydroxytoluene (BHT) and 2,6 -di-tert-butylphenol is preferred.

Also, the hindered phenol can increase the yield of the cyclic olefin copolymer by reacting with the alkylaluminum compound in the polymerization system. For this reason, it is preferred that the cocatalyst further comprises an alkylaluminum compound.
Specific examples of alkylaluminum compounds include trialkylaluminums such as trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, trisec-butylaluminum and tri-n-octylaluminum; dimethylaluminum chloride; dialkylaluminum halides such as diisobutylaluminum chloride; dialkylaluminum hydrides such as diisobutylaluminum hydride; and dialkylaluminum alkoxides such as dimethylaluminum methoxide.

The amount of the borate compound used is not particularly limited as long as the addition polymerization reaction proceeds well and a cyclic olefin copolymer having desired properties can be obtained. The amount of the borate compound used is preferably 0.01 parts by mass or more and 100 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less, relative to the total amount of 100 parts by mass of the cyclic olefin monomer and the α-olefin. 1 part by mass or more and 5 parts by mass or less is more preferable.

The amount of the hindered phenol to be used is not particularly limited as long as the addition polymerization reaction proceeds well and a cyclic olefin copolymer having desired properties can be obtained. The amount of the hindered phenol used is preferably 0.001 parts by mass or more and 100 parts by mass or less, more preferably 0.01 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the total amount of the cyclic olefin monomer and the α-olefin. , more preferably 0.1 parts by mass or more and 1 part by mass or less.

The amount of the alkylaluminum compound used is not particularly limited as long as the addition polymerization reaction proceeds well and a cyclic olefin copolymer having desired properties can be obtained. The amount of the alkylaluminum compound used is preferably 0.001 parts by mass or more and 10 parts by mass or less, more preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass as the total amount of the cyclic olefin monomer and the α-olefin. , more preferably 0.1 parts by mass or more and 1 part by mass or less.

Addition polymerization may be carried out in the presence of a solvent. The solvent is not particularly limited as long as it does not inhibit the polymerization reaction. Preferred solvents include, for example, hydrocarbon solvents and halogenated hydrocarbon solvents, and hydrocarbon solvents are preferred because they are excellent in handleability, thermal stability, and chemical stability. Specific examples of preferred solvents include hydrocarbon solvents such as pentane, hexane, heptane, octane, isooctane, isododecane, mineral oil, cyclohexane, methylcyclohexane, decahydronaphthalene (decalin), benzene, toluene, and xylene, chloroform, Halogenated hydrocarbon solvents such as methylene chloride, dichloromethane, dichloroethane, and chlorobenzene are included.

The solvent may be charged into the polymerization vessel as a solvent alone, or may be charged into the polymerization vessel in the form of a monomer solution, a catalyst solution, or a cocatalyst solution.

When using a solvent, the amount used is not particularly limited. The amount of the solvent used is preferably 100 parts by mass or more and 100000 parts by mass or less, more preferably 500 parts by mass or more and 10000 parts by mass or less, and 1000 parts by mass or more and 5000 parts by mass, based on the total amount of 100 parts by mass of the cyclic olefin monomer and the α-olefin. Part by mass or less is more preferable.

The addition polymerization temperature is not particularly limited. The addition polymerization temperature is, for example, preferably -20°C or higher and 200°C or lower, more preferably -10°C or higher and 10°C or lower, and even more preferably -5°C or higher and 5°C or lower.
When producing a cyclic olefin copolymer having a glass transition temperature in the range of less than 0°C, in the range of 0°C to 100°C, and in the range of 160°C to 300°C, addition polymerization is performed. The temperature is preferably -20°C or more and less than 10°C.
The addition polymerization time is not particularly limited. The addition polymerization time is, for example, preferably 5 minutes or more and 30 minutes or less, more preferably 8 minutes or more and 20 minutes or less, and even more preferably 10 minutes or more and 15 minutes or less.

The atmosphere in which the addition polymerization reaction is carried out is not particularly limited, but an inert gas atmosphere is preferred. Nitrogen gas or helium gas can be used as the inert gas.

After the addition polymerization is carried out as described above to produce the (A) cyclic olefin copolymer, the (A) cyclic olefin copolymer is recovered from the reaction vessel according to a conventional method.

(Second manufacturing method)
The second production method is the same as the first production method, except that the method of charging the cyclic olefin monomer and the α-olefin is not particularly limited, and that the addition polymerization is performed at a temperature within the range of 10 ° C. or higher and 60 ° C. or lower. It is the same as the manufacturing method.

The method of charging the cyclic olefin monomer and the α-olefin in the second production method may be the same as in the first production method. Since the charging operation is simple, the method for charging the cyclic olefin monomer and the α-olefin in the second production method is to batch the cyclic olefin monomer and the α-olefin at or before the start of the addition polymerization reaction. is preferably charged into the reaction vessel.

<(B) Hindered Phenolic Antioxidant>
As (B) the hindered phenol-based antioxidant, any hindered phenol-based antioxidant conventionally blended in various resin compositions can be used without particular limitation.
Here, the definition of hindered phenol is the same as the definition of hindered phenol explained in the first production method above.

(B) Specific examples of hindered phenolic antioxidants include 2,2′-methylenebis(4-methyl-6-tert-butylphenol), hexamethyleneglycol-bis(3,5-di-tert-butyl- 4-hydroxyhydrocinnamate), pentaerythritol-tetrakis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, triethylene glycol-bis-3-(3-tert-butyl-4- hydroxy-5-methylphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxy-benzyl)benzene, n-octadecyl-3-( 4'-hydroxy-3',5'-di-tert-butylphenol)propionate, 4,4'-methylenebis(2,6-di-tert-butylphenol), 4,4'-butylidene-bis(6-tert- butyl-3-methyl-phenol), di-stearyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 2-t-butyl-6-(3-tert-butyl-5-methyl-2- hydroxybenzyl)-4-methylphenyl acrylate, and 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}- 2,4,8,10-tetraoxaspiro[5,5]undecane and the like.

As described above, the content of (B) the hindered phenolic antioxidant is 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the (A) cyclic olefin copolymer.
(B) the hindered phenol-based antioxidant itself and (B) the hindered phenol-based antioxidant decomposition product volatilization and sublimation have little adverse effect during the continuous production of injection molded articles. , (B) The content of the hindered phenolic antioxidant is preferably 0.1 to 1.0 parts by mass, preferably 0.1 to 0.5 parts by mass, based on 100 parts by mass of the cyclic olefin copolymer (A). Parts by mass are more preferred.

<Other additives>
The resin composition for injection molding may contain additives other than (A) the cyclic olefin-based copolymer and (B) the hindered phenol-based antioxidant as long as the desired effects are not impaired. good.
Examples of other additives include (B) antioxidants other than hindered phenolic antioxidants, weather stabilizers, UV absorbers, antibacterial agents, flame retardants, colorants, reinforcing materials, and fillers. etc. These additives are added to the resin composition for injection molding in an amount that takes into consideration the general amount used according to the type thereof.
Other additives may be used singly or in combination of two or more.

When the injection molding resin composition contains the above-mentioned other additives, the mass ratio of the other additives to the mass of the injection molding resin composition is not particularly limited as long as the desired effect is not impaired.
The mass ratio of the other additives to the mass of the resin composition for injection molding can be appropriately adjusted according to the effect to be obtained.

<Method for producing resin composition for injection molding>
The method for producing the resin composition for injection molding is a method capable of uniformly mixing (A) the cyclic olefin copolymer, (B) the hindered phenolic antioxidant, and, if necessary, other additives. There is no particular limitation, if any.
As a preferred method for producing the resin composition for injection molding, (A) a cyclic olefin-based copolymer, (B) a hindered phenol-based antioxidant, and, if necessary, other additives are extruded through a single-screw extruder. Alternatively, a method of melt-kneading using a melt-kneading apparatus such as a multi-screw extruder with two or more screws can be mentioned.

The form of the resin composition for injection molding is not particularly limited. The resin composition for injection molding may be in the form of powder, flakes, or pellets. Typically, a resin composition for injection molding is extruded in strand form from a melt kneading apparatus. The strand-shaped resin composition for injection molding is cooled and solidified and then cut into pellets.

≪Injection molding≫
An injection-molded article is a molded article obtained by injection-molding the aforementioned resin composition for injection molding.
Injection-molded articles have both excellent breaking strain and excellent toughness, and are less likely to crack even when placed in a high-temperature, high-humidity environment.

In addition, since the injection molded article exhibits a low dielectric constant and a low dielectric loss tangent in a high frequency band, it is suitably used as a member for an electric device or electronic device used in a high frequency band, or as a substrate material. be.
Specifically, the injection molded product exhibits a dielectric constant of 2.2 or less and a dielectric loss tangent of 3.0×10 ⁻⁴ or less at 40 GHz.

The injection molded article preferably has a tensile strength of 30 MPa or more and a tensile strain at break of 8% or more as measured by a tensile test according to the method described above.

The injection molding method is not particularly limited. A well-known injection molding method can be employed without particular limitation.
The size and shape of the injection-molded article are appropriately selected according to the use of the injection-molded article.

EXAMPLES Hereinafter, the present invention will be specifically described by showing Examples, but the present invention is not limited to these Examples.

[Examples 1 to 3]
In Examples 1 to 3, 2-norbornene (Nb) and 1-octene (Oct) were added in the ratios shown in Table 1, respectively, and the total amount of 2-norbornene and 1-octene was 118.8 mmol. there was. A 500 mL eggplant-shaped flask replaced with a nitrogen atmosphere was charged with half of 2-norbornene and 1-octene, 0.198 mmol of tri-n-octylaluminum, and 2,6-di-tert-butyl-4-hydroxy. 0.396 mmol of toluene was added. Toluene was then used to dilute the contents of the flask to a volume of 258 mL. The contents of the flask were then cooled to 0°C. After cooling, a toluene solution of a titanocene catalyst with a concentration of 0.04 mmol/L was added to the reaction solution so that the amount of the titanocene catalyst was 0.22 mmol. As the titanocene catalyst, the compound represented by the above formula (2) was used. Then, a toluene solution of a borate compound with a concentration of 0.008 mmol/L was added to the reaction solution so that the amount of the borate compound was 0.22 mmol. Triphenylmethylium tetrakis(pentafluorophenyl)borate was used as the borate compound. After addition polymerization was initiated by adding the titanocene catalyst and the borate compound, the reaction mixture was reacted at 0° C. for 10 minutes while being stirred with a magnetic stirrer. After 10 minutes of reaction, the remaining half amounts of 2-norbornene and 1-octene, respectively, and 0.022 mmol of tri-n-octylaluminum and 0.044 mmol of 2,6-di-tert-butyl-4-hydroxytoluene were added. Add to an eggplant-shaped flask. The addition polymerization reaction was then allowed to continue for 15 minutes.
After the reaction for 25 minutes in total, a small amount of 2-propanol was added to the reaction solution to terminate the addition polymerization reaction. Hydrochloric acid was added to the reaction solution, and the mixture was stirred for 10 minutes, and then the organic layer was washed with deionized water. After repeating washing with ion-exchanged water until the aqueous layer became neutral, the washed organic layer was recovered. The recovered organic layer was dropped into a large amount of acetone to precipitate the cyclic olefin copolymer produced. After collecting the precipitated copolymer by filtration, the copolymer was washed with methanol and acetone two more times. The washed copolymer was dried under reduced pressure at 110° C. for 16 hours or more to obtain a dry cyclic olefin copolymer.

Regarding the obtained cyclic olefin copolymer, the molar ratio of structural units derived from α-olefin (1-octene) (α-olefin ratio) was specified by the following method.
About 50 mg of the obtained cyclic olefin copolymer was dissolved in 0.6 mL of chloroform-d, and using a BRUKER AVANCE III 400+ cryoprobe, 300 K, 90° pulse, repetition time of 30 seconds, and integration of 1000 times. A 13C-NMR spectrum was measured.
From the obtained spectrum, the α-olefin ratio was calculated based on the following formula in accordance with the method described in Macromolecules 2010, 43, 4527-4531. The results are shown in Table 1 as the Oct ratio in the resin.
Ratio of α-olefin (mol%) = [integral value of α-olefin-derived carbon / (integral value of α-olefin-derived carbon + integral value of carbon derived from cyclic olefin monomer)] × 100

The resulting cyclic olefin copolymer was subjected to molecular weight measurement by gel permeation chromatography and glass transition temperature measurement by the method described above. These measurement results are shown in Table 1.

A film used as a sample in measuring the glass transition temperature was produced by the following method.
A 50 μm deep mold was made using Kapton® film with a size of 10 cm×10 cm×50 μm. After filling the obtained cyclic olefin copolymer in the mold, using a hot vacuum press, the cyclic olefin copolymer filled in the mold was pressed under the conditions of pressure of 15 MPa, temperature of 320 to 340 ° C., and time of 15 minutes. The polymer was vacuum pressed. After pressing, the pressed cyclic olefin copolymer was rapidly cooled by sandwiching it between metal plates at room temperature. After cooling, the metal plate was removed to obtain a cyclic olefin copolymer film having a thickness of about 50 μm.

100 parts by mass of the cyclic olefin copolymer obtained according to the above method, and a hindered phenolic antioxidant (pentaerythritol-tetrakis-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate 0) .15 parts by mass are melt-kneaded under the following extrusion conditions using an extruder (manufactured by Apex Japan Co., Ltd., desktop extruder AS-1), and then the melt-kneaded product is pelletized for injection molding. A resin composition was obtained.
[Extrusion conditions]
(cylinder temperature)
Example 1: 310°C
Example 2: 300°C
Example 3: 290°C

The obtained resin composition for injection molding is injection molded using a molding machine (Small injection molding machine C, Mobile-0813, manufactured by Shinko Cellbic Co., Ltd.) under the following injection molding conditions to obtain an injection molded product, A 1BA type dumbbell specimen with a thickness of 2 mm was obtained.
In Examples 1 to 3, injection molding was performed at the following cylinder temperatures and mold temperatures.
[Molding condition]
(cylinder temperature)
Example 1: 330°C
Example 2: 320°C
Example 3: 310°C
(mold temperature)
Example 1: 150°C
Example 2: 130°C
Example 3: 120°C

The obtained injection-molded article was subjected to a high-temperature, high-humidity test according to the following method to evaluate the occurrence of moisture cracks during the high-temperature, high-humidity test. Evaluation results are shown in Table 2.
<High temperature and high humidity test>
The obtained injection molded product was treated for 168 hours at a temperature of 60° C. and a humidity of 90% using an environmental tester (small environmental tester SH-241 manufactured by Espec Co., Ltd.), and then allowed to stand at room temperature for 3 hours. . After standing at room temperature, photograph the inside of the test piece of the injection molded body using a laser microscope (manufactured by Keyence Corporation, ultra-deep color 3D shape measuring microscope VK-9510), and check the occurrence of moisture cracks according to the following criteria. evaluated.
○: No cracks (spherical grains) in the image ×: Cracks (spherical grains) in the image

Using the obtained injection molded product (1BA type dumbbell test piece), a tensile test was performed according to the following method. The results of the tensile tests are given in Table 2.
<Tensile test>
The obtained injection-molded product was subjected to tensile testing in accordance with ISO527-1 using a tensile tester (manufactured by Shimadzu Corporation, Autograph AG-Xplus) at a temperature of 23°C, a distance between chucks of 58 mm, and a tensile speed of 25 mm/min. did the test.

[Comparative Example 1]
Norbornene and 1-octene were all charged at once before starting the addition polymerization reaction, the reaction temperature was changed to 40° C., and the reaction time was changed to 4 hours. A cyclic olefin copolymer was obtained in the same manner. The charging ratio of norbornene and 1-octene is as shown in Table 1.
Regarding the obtained cyclic olefin copolymer, in the same manner as in Example 1, the Oct ratio in the resin was measured, the molecular weight was measured by gel permeation chromatography, and the glass transition temperature was measured by the method described above. These measurement results are shown in Table 1.

100 parts by mass of the cyclic olefin copolymer obtained according to the above method, and a hindered phenolic antioxidant (pentaerythritol-tetrakis-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate 0) Pellets of a resin composition for injection molding were obtained in the same manner as in Example 1, except that the cylinder temperature of the extruder was changed to 310°C.

Using the obtained resin composition for injection molding, injection molding was performed in the same manner as in Example 1, except that the cylinder temperature was changed to 290°C and the mold temperature was changed to 100°C. got In the same manner as in Example 1, the obtained injection-molded article was evaluated for the occurrence of moisture cracks during the high-temperature, high-humidity test and was subjected to a tensile test. Evaluation results are shown in Table 2.

[Comparative Example 2]
Except that 0.97 mmol of CC1 below and 0.68 mmol of CC2 below were used as promoters, the reaction temperature was changed to 40° C., and the polymerization time was changed to 4 hours. A cyclic olefin copolymer was obtained in the same manner as in 1. The charging ratio and charging method of norbornene and 1-octene are as shown in Table 1.
Regarding the obtained cyclic olefin copolymer, in the same manner as in Example 1, the Oct ratio in the resin was measured, the molecular weight was measured by gel permeation chromatography, and the glass transition temperature was measured by the method described above. These measurement results are shown in Table 1.
CC1: Methylisobutylaluminoxane represented by 6.5 mass % (as Al atom content) MMAO-3A toluene solution ([(CH ₃ ) _0.7 (iso-C ₄ H ₉ ) _0.3 AlO] _n solution, manufactured by Tosoh Finechem Co., Ltd., containing 6 mol% trimethylaluminum relative to the total Al)
CC2: 9.0% by mass (as Al atom content) TMAO-211 toluene solution (solution of methylaluminoxane, manufactured by Tosoh Finechem Co., Ltd., containing 26 mol% trimethylaluminum relative to total Al)

100 parts by mass of the cyclic olefin copolymer obtained according to the above method, and a hindered phenolic antioxidant (pentaerythritol-tetrakis-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate 0) Pellets of a resin composition for injection molding were obtained in the same manner as in Example 1, except that the cylinder temperature of the extruder was changed to 340°C.

Injection molding was attempted using the obtained resin composition for injection molding, but injection molding could not be performed. This is because the resin composition for injection molding did not flow at a temperature lower than the decomposition temperature of the resin to the extent that injection molding was possible.

[Comparative Example 3]
Except for using only 0.22 mmol of triphenylmethylium tetrakis(pentafluorophenyl)borate as a cocatalyst, changing the reaction temperature to 25° C., and changing the reaction temperature to 2 hours, Comparative Example 1 and A cyclic olefin copolymer was obtained in the same manner. The charging ratio of norbornene and 1-octene is as shown in Table 1.
Regarding the obtained cyclic olefin copolymer, in the same manner as in Example 1, the Oct ratio in the resin was measured, the molecular weight was measured by gel permeation chromatography, and the glass transition temperature was measured by the method described above. These measurement results are shown in Table 1.

100 parts by mass of the cyclic olefin copolymer obtained according to the above method, and a hindered phenolic antioxidant (pentaerythritol-tetrakis-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate 0) Pellets of a resin composition for injection molding were obtained in the same manner as in Example 1, except that the cylinder temperature of the extruder was changed to 270°C.

Using the obtained resin composition for injection molding, injection molding was performed in the same manner as in Example 1 except that the cylinder temperature was changed to 310 ° C. and the mold temperature was changed to 140 ° C. got a body In the same manner as in Example 1, the obtained injection-molded article was evaluated for the occurrence of moisture cracks during the high-temperature, high-humidity test and was subjected to a tensile test. Evaluation results are shown in Table 2.

According to Tables 1 and 2, the ratio of the number of moles of α-olefin-derived structural units to the number of moles of all structural units is 10 mol% or more and 40 mol% or less, and the glass transition temperature measured by viscoelasticity measurement is , the cyclic olefin copolymers (A) prepared in Examples 1 to 3, which have two or more in the range of 0 ° C. to 300 ° C., exhibit excellent tensile properties, excellent breaking strain and excellent toughness. I know you have it.
For this reason, the injection molded articles obtained using the injection molding compositions containing the (A) cyclic olefin copolymers prepared in Examples 1 to 3 also have excellent breaking strain and excellent toughness.
Further, the injection molded articles obtained using the injection molding resin compositions of Examples 1 to 3, which contain (B) a hindered phenolic antioxidant, do not crack even when placed in a high temperature and high humidity environment. It was difficult to occur.
On the other hand, the glass transition temperature by viscoelasticity measurement of Comparative Examples 1 to 3 containing (A) the cyclic olefin copolymer prepared in Comparative Examples 1 to 3 having only one in the range of 0 ° C. to 300 ° C. Even if the resin composition for injection molding contains (B) a hindered phenolic antioxidant, moisture cracks are likely to occur, or at least one of tensile strength, breaking strain, and tensile modulus is inferior. In addition, the occurrence of moisture cracks could not be evaluated because the injection molding could not be performed because it did not flow below the decomposition temperature.

Claims (5)

A resin composition for injection molding comprising (A) a cyclic olefin copolymer and (B) a hindered phenol-based antioxidant,
The (A) cyclic olefin copolymer is a cyclic olefin copolymer that is an addition-type polymer of a cyclic olefin monomer and an α-olefin having 3 to 20 carbon atoms,
The ratio of the number of moles of structural units derived from the α-olefin to the number of moles of all structural units of the (A) cyclic olefin copolymer is 10 mol% or more and 40 mol% or less,
The (A) cyclic olefin copolymer has two or more glass transition temperatures in the range of 0° C. to 300° C. by viscoelasticity measurement,
A resin composition for injection molding, wherein the content of the (B) hindered phenolic antioxidant is 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the (A) cyclic olefin copolymer. . The injection molding according to claim 1, wherein the (A) cyclic olefin copolymer has at least one glass transition temperature within the range of 0°C to 100°C and within the range of 160°C to 300°C. resin composition for The (A) cyclic olefin copolymer has at least one glass transition temperature in the range of less than 0°C, in the range of 0°C to 100°C, and in the range of 160°C to 300°C, respectively. The resin composition for injection molding according to claim 1 or 2. An injection-molded article comprising the resin composition for injection molding according to any one of claims 1 to 3. 5. The injection molded article according to claim 4, which has a tensile strength of 30 MPa or more and a tensile breaking strain of 8% or more, as measured according to ISO527-1.