JPH08231660A - Block copolymer and preparation thereof - Google Patents

Abstract

PURPOSE: To prepare a block copolymer comprising (meth)acrylic ester/olefin/(meth)acrylic ester blocks and having a narrow mol.wt. distribution by using a particular initiator. CONSTITUTION: An A-B-A type block copolymer comprising a polymer block (A) of a (meth)acrylic ester and a polymer block (B) of an olefin and having an Mw/Mn of 1.0 to 2.5. This copolymer is prepd. by polymerizing an olefin in the presence of a polymn. initiator of an organic rare earth compd. represented by formula I (M represents Sc, Y, or lanthanide metal; Cp represents a (substd.)cyclopentadienyl; R and R<1> each represents H or a 1-5C hydrocarbon group; and n is 1 to 10) or formula II (R1 and R2 represent each a 1-5C hydrocarbon group or a hydrocarbon group contg. a silicon atom; Z1 and Z2 represent a 1-3C alkylene, alkylsilyl, or alkylsiloxane; M represents Sm, Er, or Yb; D represents a solvent molecule; and n is 0 to 3) and then polymerizing an (meth) acrylic ester.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a block copolymer and a method for producing the same.

[0002]

2. Description of the Related Art Polyolefin has the drawback that it has poor adhesiveness, printability and compatibility with other polymers because it has no polar group in the molecule. Copolymerization of olefins with polar monomers has been attempted to remedy these drawbacks. By copolymerizing poly (methyl methacrylate) with an olefin, it is possible to impart functions such as improvement of impact resistance, improvement of flexibility, reduction of water absorption, and surface hydrophobicization.

As a method for producing these copolymers, for example, JP-A-59-43003 discloses a method of synthesizing a copolymer using a titanium-based catalyst, and JP-A-64-
Japanese Patent No. 14217 discloses a method for synthesizing a copolymer using a nickel catalyst. However, both of these methods have a problem that it is necessary to use a large amount of Lewis acid or aluminoxane as a cocatalyst.

Further, JP-A-1-201302, JP-A-1-201304, and JP-A-63-43.
In Japanese Patent No. 914, after modifying the polyolefin end,
Although a method of copolymerizing a (meth) acrylic acid ester is disclosed, there is a problem that the introduction rate of the modified terminal is low and a homopolymer of the (meth) acrylic acid ester is by-produced.

Further, in JP-A-3-255116 and JP-A-4-53813, a method of synthesizing an ethylene- (meth) acrylic acid ester copolymer using a monofunctional trivalent rare earth compound. However, the former cannot obtain a copolymer having a high content of methyl methacrylate (MMA), and the latter has a wide Mw / Mn of 2 or more due to a chain transfer reaction in the polymerization step of ethylene, A polymer of ethylene is produced as a by-product. Further, in these methods, since ethylene does not act on the growth end of the (meth) acrylic acid ester, only a binary block copolymer of ethylene- (meth) acrylic acid ester can be produced.

On the other hand, recently, a bifunctional rare earth complex has been proposed as a polymerization initiator for the production of a homopolymer of ethylene or a copolymer of ethylene and another monomer. Wil
iam J Evans et. al. (J. Am.
Chem. Soc. , 1990, 112, 2314-2
In 324), ethylene is polymerized using a bifunctional rare earth complex as an initiator. Also, Bruce M. et al. Nova
k and Lisa S. Boffa (ACS Pol
ymer Prepprint, 35 (2), 1994.
And Boffa, MACRO AKRON '94,
117. ) Synthesizes a polymethylmethacrylate block-polyethylacrylate block-polymethylmethacrylate block ternary block copolymer using a bifunctional rare earth complex as an initiator. Furthermore, Yasuda et al. (Pol
ymer Prepprints, Japan Vol
43, No. 6 (1994)) polymerizes ethylene using a divalent samarium complex as an initiator. But,
None of these documents suggest the ABA type block copolymer of the present invention.

Generally, divalent samarium complexes are described in "PL.
Watson and T.W. Herskorvitz
ACS symposium series No.
212 p459-479 ".
It is known that when ethylene is reacted, the polymerization proceeds according to the following formula (III). That is, if both ends of the produced polymer are living ends, it is possible to synthesize an ABA type block copolymer by adding another type of monomer.

[0008]

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The inventors of the present invention proposed synthesis of an ABA type block copolymer of ethylene and a (meth) acrylic acid ester by utilizing this idea in JP-A-6-306112. (Mw / Mn) of the obtained copolymer was 4
There was a problem that the molecular weight distribution was wide and the amount of by-produced polymer such as a binary block copolymer or a homopolymer of methyl methacrylate was large.

[0010]

Means for Solving the Problems The inventors of the present invention have made extensive studies in view of such circumstances, and as a result, by using a specific initiator, a (meth) acrylic acid ester-olefin-having a narrow molecular weight distribution is obtained. It was found that a block copolymer of (meth) acrylic acid ester can be obtained, and the present invention was completed.

That is, the present invention is an ABA type copolymer comprising a polymer block A of (meth) acrylic acid ester and a polymer block B of olefin,
The Mw (weight average molecular weight) / Mn (number average molecular weight) is 1.0 to 2.5, and a block copolymer characterized by the following general formula (I)
Alternatively, it is a production method obtained by polymerizing an olefin by using an organic rare earth compound represented by (II) as a polymerization initiator and then polymerizing a (meth) acrylic acid ester.

[0012]

[Chemical 4]

[0013]

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[0014]

BEST MODE FOR CARRYING OUT THE INVENTION (Meth) acrylic acid ester used for constituting polymer block A of (meth) acrylic acid ester in the block copolymer of the present invention (hereinafter, simply referred to as polymer block A). Is not particularly limited, but specifically, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, isoamyl acrylate, Acrylic esters such as lauryl acrylate, benzyl acrylate, phenyl acrylate, vinyl acrylate, glycidyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n methacrylate
-Propyl, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid t
-Butyl, isoamyl methacrylate, lauryl methacrylate, benzyl methacrylate, phenyl methacrylate,
Vinyl methacrylate, glycidyl methacrylate, 2-ethylhexyl methacrylate, 2-methoxyethyl methacrylate, diethylene glycol monomethyl ether methacrylate and the like can be mentioned. Preferred are methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, lauryl methacrylate, n-butyl acrylate, and methyl acrylate. In addition, you may use these monomers individually or in mixture of 2 or more types.

Examples of the olefin used for constituting the olefin polymer block B of the present invention (hereinafter, simply referred to as polymer block B) include ethylene, propylene, 1-butene and 4-methyl-1. -Pentene, 1-hexene, 1-octene, 1-decene and the like can be mentioned. Preferably ethylene, propylene,
1-hexene.

The block copolymer which can be synthesized by the production method of the present invention is composed of the above polymer block A and the above polymer block B in an ABA type arrangement. A is a mixture of two or more (meth) acrylic acid esters, for example, A'-ABA-A-A 'and A "-A'-A-B-A-A'-A" type 3 It is also possible to use block copolymers of the original or above. The polymer block A can also be a random copolymer of two or more types of (meth) acrylic acid ester.

The Mw / Mn of the block copolymer of the present invention is not particularly limited as long as it is 1.0 to 2.5, but it is more preferably 1.0 to 2.0.

The molecular weight of the block copolymer of the present invention is not particularly limited, but the number average molecular weight (Mn) is 1,000 to 1,000,000 for the polymer block A and 1,000 for the polymer block B. It is preferably in the range of 1,000,000. More preferably polymer block B
Is in the range of 10,000 to 1,000,000. The total number average molecular weight (Mn) of the block copolymer is preferably in the range of 3,000 to 3,000,000, more preferably in the range of 12,000 to 2,000,000.

The block copolymer of the present invention can be obtained by the following method using the organic rare earth complex represented by the above general formula (I) or (II) as an initiator. First, as the first step, olefin is introduced into a solvent in an inert atmosphere to polymerize the olefin. Then, it can be obtained by adding a (meth) acrylic acid ester and carrying out a second stage polymerization. Two or more kinds of (meth) acrylic acid ester are used, and the polymer block A is (meth)
In the case of making an acrylic acid ester block, first, one kind of (meth) acrylic acid ester is polymerized, and then another kind of (meth) acrylic acid ester is added and polymerized.
In addition, the polymer block A can be obtained by mixing each monomer, then adding and polymerizing the monomer to make it a random copolymer of (meth) acrylic acid ester.

Olefin and (meth) used for polymerization
The acrylic ester is preferably dried by calcium hydride, molecular sieve or the like, and when the monomer is liquid or solid, it is preferably distilled before polymerization.

The organic rare earth compound used in the present invention is
The compound is represented by the above general formula (I) or (II), and specific examples of the formula (I) include [(C ₅ Me ₅ ) ₂ Sm (μ-η ³ -CH ₂ CHCHC
_{H 2 -)] 2, [} (C 5 Me 5) 2 Sm (μ-η 3 -CH 2 CHCH
_{-)] 2, [(C} 5 Me 5) 2 Yb (μ-η 3 -CH 2 CHCHC
_{H 2 -)] 2, [} (C 5 Me 5) 2 Yb (μ-η 3 -CH 2 CHCH
_{-)] 2, [(C} 5 Me 5) 2 Eu (μ-η 3 -CH 2 CHCHC
_{H 2 -)] 2, [} (C 5 Me 5) 2 Eu (μ-η 3 -CH 2 CHCH
-)] _{2 and the} like.

A specific example of the formula (II) is [(Me ₂ Si) (Me ₂ SiOSiMe ₂ ) (4-t
_{-Bu-1,2-C 5 H 3} ) 2] Sm (thf) 2 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-t
_{-Bu-1,2-C 5 H 3} ) 2] Yb (thf) 2 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-t
_{-Bu-1,2-C 5 H 3} ) 2] Er (thf) 2 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-T
_{MS-1,2-C 5 H 3} ) 2] Sm (thf) 2 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-T
_{MS-1,2-C 5 H 3} ) 2] Yb (thf) 2 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-T
_{MS-1,2-C 5 H 3} ) 2] Er (thf) 2 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-t
_{-Bu-1,2-C 5 H 3} ) 2] Sm (thf) 3 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-t
_{-Bu-1,2-C 5 H 3} ) 2] Yb (thf) 3 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-t
_{-Bu-1,2-C 5 H 3} ) 2] Er (thf) 3 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-T
_{MS-1,2-C 5 H 3} ) 2] Sm (thf) 3 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-T
_{MS-1,2-C 5 H 3} ) 2] Yb (thf) 3 [(Me 2 Si) (Me 2 SiOSiMe 2) (4-T
_{MS-1,2-C 5 H 3} ) 2] Er (thf) 3 , and the like.

In the above general formula (II), R ₁ , R ₂ ,
Z ₁ , Z ₂ , D and n are organic rare earth compounds [(Me ₂ S
i) (Me ₂ SiOSiMe ₂ ) (4-t-Bu-1,
2-C ₅ H ₃ ) ₂ ] Sm (thf) ₂ has R ₁ , R ₂
Is t-Bu (tertiary butyl group), Z ₁ is M
e ₂ Si (dimethylsilyl group), Z ₂ is Me ₂ SiOS
iMe ₂ (1,1,3,3-tetramethylsiloxane group), D is thf (tetrahydrofuran), and n is an integer of 2. Moreover, TMS shows a trimethylsilyl group.

The amount of the organic rare earth compound used is 0.001 with respect to 1 mol of the (meth) acrylic acid ester monomer.
˜100 mmol, preferably 0.01 to 10 mmol.

The inert gas used in the polymerization is not particularly limited, but argon, helium, nitrogen and the like are used, and argon is preferable.

The solvent used in the polymerization includes hydrocarbons such as toluene, xylene, benzene, hexane and tetralin, halogenated hydrocarbons such as chloroform, methylene chloride, carbon tetrachloride, dichlorobenzene and trichlorobenzene, tetrahydrofuran and ether. Etc. Toluene and xylene are preferable. It is preferable to use a completely dehydrated solvent, and the amount of the solvent used is in the range of 1 to 50,000 ml based on 1 mol of the (meth) acrylic acid ester.

The polymerization temperature is not limited as long as it is between the melting point and the boiling point of the solvent, but is preferably in the range of -78 ° C to 80 ° C. More preferably, it is in the range of -40 ° C to 40 ° C.

In the method of the present invention, when the concentration of the polymerization initiator and the concentration of the olefin monomer are determined, the reaction temperature,
By adjusting the polymerization time, the degree of polymerization of the polymer block B part can be freely adjusted, and the (meth)
The degree of polymerization of the polymer block A portion can be freely adjusted by adjusting the concentration of the acrylic acid ester monomer and the polymerization time.

The raw materials used in the examples were purified as follows.

(1) Purification of (meth) acrylic acid ester A commercially available product was dehydrated and distilled with calcium hydride,
A trace amount of water was removed with a molecular sieve, and vacuum distillation was performed immediately before use.

(2) Purification of ethylene Immediately before use, the product was passed through a molecular sieve and dehydrated.

(3) Purification of Toluene A commercially available product was dehydrated with Na / K alloy and distilled just before use.

[0033]

The present invention will be described below in detail with reference to examples. The physical properties in the examples were measured by the following methods.

(1) Mn and Mw / Mn High temperature GPC (gel permeation chromatography) was used for measurement (solvent: trichlorobenzene, temperature: 135 ° C., standard: polystyrene).

(2) Composition ratio of block copolymer Calculated by ¹ H NMR (solvent; p-xylene-d
₁₀ , measurement temperature; 120 ° C).

Example 1 (1) Initiator [(Me ₂ Si) (Me ₂ SiOSiMe
_{2) (4-t-Bu} -1,2-C 5 H 3) 2] Sm (t
hf) ₃ Synthesis of SmI ₂ (11.5 mmol) in tetrahydrofuran (THF) solution 120 m prepared under argon flow
1, the potassium salt of the ligand [(Me ₂ Si) (Me ₂ S
_{iOSiMe 2) (4-t-} Bu-1,2-C 5 H 3)
60 ml of a THF solution of ₂ ] K ₂ (11.8 mmol) was added dropwise, and the mixture was refluxed for 12 hours. Next, after removing the solvent-insoluble portion, the solvent was distilled off under reduced pressure to dryness, and 70 ml of toluene was added to the residue. After stirring this for 12 hours, the insoluble portion was removed to obtain a supernatant. Then, toluene was distilled off under reduced pressure to dryness, and the residue was dissolved in 50 ml of THF. The solution was concentrated to 1/2 volume under reduced pressure and cooled to −20 ° C. to give a black-red-purple complex [(Me ₂ Si) (Me ₂ SiOS).
_{iMe 2) (4-t-} Bu-1,2-C 5 H 3) 2] S
m (thf) ₃ was obtained with a yield of about 45%. This complex showed the following absorption spectrum in ¹ H NMR (C ₆ D ₆ , 25 ° C., PPM). δ-4.99 (s, 18H), -2.54 (s, 3)
H), -1.09 (s, 6H), 3.19 (bs, 12)
H), 6.30 (s, 2H), 10.51 (bs, 12)
H), 10.75 (s, 3H), 11.26 (s, 6
H), 41.26 (s, 2H)

(2) Synthesis of Copolymer A (Me ₂ Si) (Me ₂ SiOSiMe ₂ ) (4-t-
_{Bu-1,2-C 5 H 3} ) 2 Sm (thf) 3 complexes 0.
After dissolving 02 mmol in 15 ml of toluene, argon gas was replaced with ethylene gas by cooling and degassing. After ethylene was polymerized at room temperature for 5 minutes, unreacted ethylene gas was cooled and degassed to introduce argon. 5 ml of the produced solution containing polyethylene was sampled with a syringe. 0.5 ml of methyl methacrylate was added to 10 ml of the remaining reaction solution, and the mixture was reacted at room temperature for 2 hours.

Then, the reaction solution was put in a large amount of methanol to precipitate a polymer, which was filtered, washed with methanol, and dried in vacuum to obtain a powdery polymer. Subsequently, this polymer was subjected to Soxhlet extraction with acetone, washed, and dried to form a powdery terpolymer block copolymer of methyl methacrylate (MMA) polymer-ethylene polymer-methyl methacrylate (MMA) polymer. 107 mg was obtained. No change in weight was observed before and after soxhlet extraction.

Table 1 shows the molecular weight (Mn) and molecular weight distribution (Mw / M) of the obtained ternary block copolymer by GPC.
The measurement result of n) and the composition ratio of the copolymer calculated by ¹ H NMR are shown. In addition, ¹ H of block copolymer
The NMR data are as follows. ¹ H NMR (p-xylene-d ₁₀ , 120 ° C., PP
M): δ-1.1 to 1.3 (-Me; PMMA), 1.
_{4 (-CH 2 -, PE)} , 2.1 (-CH 2 -; PMM
A), 3.5 (-OMe; PMMA)

[Example 2] M was prepared in the same manner as in Example 1 except that the polymerization time of ethylene was changed to 2 minutes.
3 consisting of MA polymer-ethylene polymer-MMA polymer
An original block copolymer was obtained. The results are shown in Table 1.

[Example 3] A ternary block copolymer comprising an MMA polymer-ethylene polymer-MMA polymer was prepared in the same manner as in Example 1 except that the polymerization time of ethylene was changed to 10 minutes. Got The results are shown in Table 1.

Example 4 (1) Initiator [(C ₅ Me ₅ ) ₂ Sm (μ-η ³ -CH
₂ CHCHCH ₂ —)] ₂ Synthesis of (C ₅ Me
₅ ) ₂ Sm (thf) ₂ complex 7.14 mmol was added,
It stirred at 60 degreeC and the pressure of 10-5 Torr for 6 hours.
After the color of the complex changed from magenta to dark green, hexane 50 was added.
ml was added. The solution was then vacuum degassed, 1,3
-Butadiene gas was introduced. The mixture was stirred at room temperature for 5 hours, and the formed orange precipitate was obtained by centrifugation. After completely dissolving this precipitate in toluene, the solution is halved.
When concentrated to an amount and cooled to −20 ° C., the red-orange color [(C ₅ Me ₅ ) ₂ Sm (μ-η ³ -CH ₂ CHCHC
H ₂ -)] ₂ complex was obtained in 55.3% yield.

(2) Synthesis of copolymer In a 100 ml flask purged with argon, [(C ₅ Me ₅ ) ₂ Sm (μ-η ³ -CH ₂ CHCHC) of the above synthesis was used.
H ₂ −)] ₂ complex (0.09 mmol) in toluene (20 ml)
Then, the argon gas was replaced with ethylene gas by cooling degassing. After polymerizing ethylene at room temperature for 20 minutes, unreacted ethylene gas was cooled and degassed, and argon was introduced. Solution containing polyethylene 10
ml was sampled with a syringe. Remaining reaction solution 1
0.5 ml of methyl methacrylate was added to 0 ml with a syringe, and the mixture was stirred at room temperature for 30 minutes for reaction.

Then, the reaction solution was put into a large amount of methanol to precipitate a polymer, which was then filtered, washed with methanol, and then vacuum dried to obtain a powdery MMA polymer.
A ternary block copolymer consisting of an ethylene polymer-MMA polymer was obtained. The results are shown in Table 1.

[Example 5] A ternary block copolymer comprising an MMA polymer / ethylene polymer / MMA polymer was prepared in the same manner as in Example 4 except that the polymerization time of ethylene was changed to 30 minutes. Got The results are shown in Table 1.

[0046]

[Table 1]

[0047]

According to the present invention, an ABA type block copolymer having a narrow molecular weight distribution, which could not be obtained by the conventional method, can be easily produced. In addition, the ABA block copolymer of the present invention is excellent in adhesiveness, printability, and compatibility with other polymers, and is extremely useful for applications such as paints and adhesives. In addition, it is possible to impart functions such as impact resistance improvement, flexibility improvement, water absorption reduction, and surface hydrophobicization to the polymethacrylic acid ester.

Front page continued (72) Inventor's rank Shimon Jin 3 Kaigan Dori, Toyama City, Toyama Prefecture Mitsubishi Rayon Co., Ltd., Toyama Works (72) Inventor Seiji Tohaku 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Chuo Inside the Technical Research Institute (72) Inventor Toru Tomitsu 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Technical Research Institute

Claims (3)

[Claims] 1. An ABA type copolymer comprising a polymer block A of a (meth) acrylic acid ester and a polymer block B of an olefin, wherein Mw (weight average molecular weight) / Mn thereof. A block copolymer having a (number average molecular weight) of 1.0 to 2.5. 2. The (meth) acrylic acid ester is polymerized after polymerizing an olefin using a bifunctional rare earth compound represented by the following general formula (I) as a polymerization initiator. A method for producing a block copolymer. Embedded image 3. The block according to claim 1, wherein the (meth) acrylic acid ester is polymerized after polymerizing an olefin by using an organic rare earth compound represented by the following general formula (II) as a polymerization initiator. Method for producing copolymer. Embedded image