JPH05230212A - Block copolymer and its production - Google Patents

Abstract

PURPOSE:To obtain the title segmented copolymer excellent in flexibility, transparency, mechanical strengths and heat resistance, comprising specified repeating units and having a specified reduced viscosity and a specified degree of imidization. CONSTITUTION:The title copolymer comprises repeating units of the formula (wherein n is 1-85; Z is a 6-24C aromatic group; R is a 2-24C aliphatic group or an aromatic group; and G is a polyoxyalkylene chain of an average molecular weight of 500-5000) and has a reduced viscosity of 0.1-13.0dl/g as measured in N-methyl-2-pyrrolidone at 30 deg.C and a degree of imidization of 0.5 or above.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a segmented block copolymer having a polyether chain as a soft segment and a polyimide as a hard segment. INDUSTRIAL APPLICABILITY The block copolymer of the present invention can be used as a coating material or a coating material in various automobile parts, industrial parts and electric / electronic fields that require heat resistance and oil resistance.

[0002]

2. Description of the Related Art Various thermoplastic elastomers that have been industrially manufactured have been known.

[0003] Polyester thermoplastic elastomers are known to have particularly excellent heat resistance and are being developed for rubber applications, and have been developed for various applications including automobile applications.

However, ester-based thermoplastic elastomers have the fatal drawback of being inferior in dynamic heat resistance to general-purpose cross-linked rubbers, and those having a high hardness are the mainstream, so that they are used as rubber substitutes. Making it difficult to deploy. In fact, even the polyester-based thermoplastic elastomer, which has the highest heat resistance among the currently known thermoplastic elastomers, has a usable temperature of 100 ° C or less in a continuous dynamic environment, which is equivalent to that of a general-purpose crosslinked rubber. It does not have heat resistance.

Further, a thermoplastic elastomer using polyimide as a hard segment is known (Journal of Applied Polymer Science, No. 44).
Vol. 409, 1992). Among the polyoxyalkylene chains, especially polytetramethylene chains are used for the soft segment, that is, the elastomer segment, used in this block copolymer from the viewpoint of heat resistance. The molecular weight of the polyoxyalkylene chain affects the hardness or elastic modulus of the resulting block copolymer. It is well known that when a low molecular weight soft segment having a number average molecular weight of 1000 or less is used, the hardness of the block copolymer produced becomes very high, which is a problem when considering its use as an elastomer. On the other hand, it is also known that when a relatively high molecular weight soft segment having a number average molecular weight of 1000 or more is used, the resulting block copolymer becomes an elastomer having poor cold resistance due to crystallization of the soft segment. In the polyester-based thermoplastic elastomer, low molecular weight polytetramethylene glycol is preferably used as the soft segment. Further, when a chain extension product of low molecular weight polyalkylene glycol such as terephthalic acid and / or isophthalic acid is used as the soft segment component of the block copolymer, it has low crystallinity and becomes a very excellent soft segment. Is also known.

[0006]

SUMMARY OF THE INVENTION In view of such facts,
Recently, research has been conducted to produce heat resistant thermoplastic elastomers. A segmented block polyetherester elastomer having a liquid crystal component as a hard segment (JP-A-3-97725, JP-A-3-97725)
No. 97726), or segmented ether imide block copolymers (JP-A-2-235962). Currently, thermoplastic elastomers having dynamic heat resistance close to that of a cross-linkable elastomer are Not obtained.

In the above-mentioned method for producing an imide-based polymer, it has been confirmed that the crystallinity is lowered by using a low molecular weight polyether having a molecular weight of 2000 or less, and a block copolymer having excellent physical properties is obtained. ing. But,
In the above method, the block copolymer is obtained by linking the polytetramethylene glycol diamine, which is the soft segment, with the aromatic tetracarboxylic dianhydride, and the hardness absolutely required in the production of the elastomer material. However, there is a problem in that it cannot be controlled.
Further, since it has an ester bond in the main chain, further improvement in hydrolysis resistance is expected.

[0008]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors found that a segmented block copolymer using polyalkylene oxide as a soft segment and polyimide as a hard segment is excellent. Further, they have found that it is a low-hardness thermoplastic elastomer having dynamic thermal stability and excellent transparency, and thus the present invention has been completed.

That is, the present invention provides the following general formula (1)

[0010]

[Chemical 5] (Here, n is an integer of 1 to 85 representing the degree of polymerization, and Z
Represents an aromatic group having 6 to 24 carbon atoms, and R represents 2 to 2 carbon atoms.
4 represents an aliphatic or aromatic group, and G has an average molecular weight of 50.
(Representing a polyoxyalkylene chain of 0 to 5000) and having a reduced viscosity of 0.1 to 13.0d measured at 30 ° C. in N-methyl-2-pyrrolidone.
a segmented block copolymer having an imidization ratio (Di) of 0.5 or more, and a. The following general formula (2)

[0011]

[Chemical 6] (Wherein G represents a polyoxyalkylene chain having a number average molecular weight of 500 to 5000) and b. The following general formula (3)

[0012]

[Chemical 7] (Wherein R represents an aliphatic or aromatic group having 2 to 24 carbon atoms) and the following general formula (4).

[0013]

[Chemical 8] (Wherein Z represents an aromatic group having 6 to 24 carbon atoms), which is obtained by reacting an aromatic tetracarboxylic acid anhydride represented by the reaction with an acid anhydride group-terminated polyamic acid. It relates to a method for producing the above-mentioned segmented block copolymer, which comprises imidizing the block copolymer.

The present invention is described in detail below.

The aromatic tetracarboxylic acid anhydride used in the present invention is not particularly limited, but the following are exemplified. That is, pyromellitic anhydride, 3,
3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4)
-Dicarboxyphenyl) hexafluoropropane dianhydride, 1,2,3,4-tetracarboxybutane dianhydride, or esterified derivatives of these acid anhydrides such as dialkyl ester dicarboxylic acid compounds can be used. ..

As the diamine compound constituting the hard segment, aromatic and aliphatic diamine compounds can be used, for example, m-phenylenediamine and p.
-Phenylenediamine, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, 4,
4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-
Diaminobenzidine, 3,3-dimethoxybenzidine,
2,4-bis (β-amino-t-butyl) toluene, bis (p-amino-t-butylphenyl) benzene, 1,
3-diamino-4-isopropylbenzene, m-xylylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, bis (4-aminocyclohexyl) methane, 3-methylheptamethylenediamine, 4,4-dimethyl Heptamethylenediamine, 2,11-dodecanediamine, 2,2-dimethylpropylenediamine, octamethylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylhexamethylenediamine, 2,5
-Dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine,
1,4-cyclohexanediamine, 1,12-octadecanediamine, bis (3-aminopropyl) sulfide, N-methyl-bis (3-aminopropyl) amine,
Hexamethylenediamine, heptamethylenediamine, nonamethylenediamine, decamethylenediamine and the like can be mentioned.

Examples of the soft segment that can be used are long-chain polytetramethylene ether diamines, polyethylene ether diamines, polypropylene ether diamines, and other polyalkylene ether diamines. It can be prepared by amination of the corresponding polyoxyalkylene glycol. As the glycol, other than that, a cation ring-opening copolymer of propylene oxide and cyclic ethers can be used, and a product obtained by capping the terminal with propylene or ethylene and then aminated can also be used. That is, bisaminoethyl polytetrahydrofuran, bisaminopropyl polytetrahydrofuran, bisaminobutyl polytetrahydrofuran, etc. can be used. Methods for producing these long-chain polyether diamines are known, for example, US Pat.
The methods described in 155728, US Pat. No. 3,236,895, US Pat. No. 3,654,370 and the like can be used. As the molecular weight of the soft segment, those having a number average molecular weight of 600 to 5,000 can be used, and those having a number average molecular weight of 900 to 3,000 are particularly preferably used. Further, as the soft segment, a chain extension of the above-mentioned polymer can be similarly used. As the soft segment, it is preferable to use one having no crystal melting point near room temperature, and from this viewpoint, it is particularly necessary to set the molecular weight of the polyalkylene ether diamine.

As the reaction solvent, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-acetyl-
Pyrrolidone-based solvent such as 2-pyrrolidone, sulfolane,
γ-butyrolactone, N, N-dimethylacetamide,
Hexamethylphosphoramide, N, N-dimethylformamide, N, N-dimethylmethoxyacetamide and other amide solvents, dimethyl sulfoxide, diethyl sulfoxide and other sulfoxide solvents, phenol, o
-Phenol solvents such as -cresol, m-cresol, p-cresol, orthochlorophenol, p-bromophenol, ether solvents such as diglyme, tetrahydrofuran, tetrahydropyran, tetramethylurea,
Pyridine, dimethyl sulfone, N-methyl-ε-caprolactam and the like can be used. It is also possible to use a mixed solvent with various solvents that are compatible with the above solvents, such as benzene and dioxane.

The reaction temperature is not particularly limited, but is usually 0 to
The range of 180 ° C. is used, and the range of 0 to 150 ° C. is preferable.

The method for synthesizing the polyamic acid which is the precursor of the hard segment will be described below. The polyamic acid can be obtained by reacting an acid anhydride and an aromatic diamine compound in the above-mentioned solvent in the range of 0 to 50 ° C. At this time, the charging ratio of the acid anhydride and the diamine compound can be determined from the degree of polymerization of polyamic acid having a desired molecular weight. That is, when the charged mole of the acid anhydride is n and the charged mole number of the diamine compound is m, the degree of polymerization can be adjusted by changing the ratio n / m. In addition, the terminal structure can be similarly controlled, and an acid anhydride group terminal polyamic acid can be synthesized by using an excess amount of the acid anhydride with respect to the diamine compound. The polyamic acid solution can be diluted with the above-mentioned solvent, and the polyamic acid can also be synthesized in this mixed solvent. Further, the solvent can be removed and concentrated under reduced pressure. Furthermore, if desired, the polyamic acid can be isolated by precipitation by a known method, and this isolate can also be used for the synthesis of the block polymer.

By reacting the obtained solution of the polyamic acid oligomer with the above-mentioned long-chain aliphatic diamine or a solution thereof, an elastomer-like segmented block polymer comprising a polyamic acid segment and an aliphatic soft segment can be obtained. In this reaction, the ratio of the number of moles of the acid anhydride group of the polyamic acid having an acid anhydride group at the terminal and the number of moles of the terminal amine of the polyalkylene oxide diamine is preferably 0.7 to 1.5,
A ratio of 0.9 to 1.1 is particularly preferably used. The reaction between the polyalkylene oxide diamine and the polyamic acid is preferably 0 to 180 ° C, and particularly preferably 0 to 100 ° C.

The imidization of the obtained prepolymer will be described below. The imidization method of polyamic acid is known, and the method explained below can be used.

A method in which a polymer is not isolated from a prepolymer solution, but trialkylamines such as triethylamine and tributylamine or pyridine derivatives such as pyridine and 2-hydroxypyridine and acetic anhydride are added to the reaction solution is preferably used. The addition amount of the trialkylamines or the pyridine derivative is preferably 1.1 to 12 times mol per mol of the carboxyl group of the polyamic acid. There is no problem if acetic anhydride is added in excess of the number of moles of water produced, and 1.0 to 12 times the number of moles of water normally produced is preferably used. The order of addition of these imidizing agents does not particularly affect imidization,
It is preferable to add the trialkylamines or the pyridine derivative, which are ring-closing catalysts, first. The method of adding the amines and acetic anhydride to the polymer solution may be either batch addition or dropwise addition.

Further, in order to remove water generated by imidization, the above-mentioned imidizing agent is added or not added to the prepolymer solution, and an organic solvent azeotropic with water represented by toluene is added. ~ 180 ° C, preferably 1
A method of imidizing at 50 to 180 ° C can also be used.

Further, after isolation of the imidized product in the solution,
In order to improve the imidization ratio, it is possible to perform heat treatment at 70 to 200 ° C, preferably 100 to 180 ° C.

The reduced viscosity of the block copolymer of the present invention is preferably in the range of 0.1 to 13.0 dl / g, particularly preferably 0.2 to 6.0 dl / g. When the reduced viscosity exceeds 13.0, there is a problem in moldability, and when it is less than 0.1, only those having poor mechanical properties can be obtained.

The imidation ratio of the block copolymer of the present invention is 0.5 or more, particularly preferably 0.8 or more. If the imidization ratio is less than 0.5, intermolecular cross-linking occurs, and the rubber performance is poor, which is not preferable.

Various fillers and pigments can be added to the block copolymer of the present invention. For example, titanium dioxide, silicon oxide, carbon black, etc. are exemplified.

[0029]

The present invention will be described in detail below with reference to examples.

The analytical instruments and methods used for the analysis of the block copolymer of the present invention are shown below. (1) Infrared absorption spectrum is from NICOLET 5
Using DXC FT-IR, the resolution was 2 cm ⁻¹ and the integration was performed 100 times. Furthermore, IR2 made by Hitachi
A 30-30 spectrophotometer was used in combination. (2) ¹ H-NMR spectrum is JEO made by JEOL
It measured using LPMX-60NMR using deuterated DMSO as a solvent. (3) TGA is TG-DTA2 manufactured by Seiko Instruments Inc.
00 was used and the temperature was raised at a rate of 10 ° C./min in a nitrogen stream. (4) Dynamic viscoelasticity measurement is DVE manufactured by Rheology Co., Ltd.
-V4, thickness 0.6mm, width 0.5mm, length 1
The measurement was performed using a 5 mm press sheet under the conditions of a temperature rising rate of 2 ° C./minute, an amplitude of 10 microns, and a frequency of 11.0 Hz. (5) Mechanical properties (breaking strength, breaking elongation) were measured using Shimadzu's Autograph DCS-1000 using a press sheet having a thickness of 0.6 mm. (6) The hardness was measured by a micro rubber hardness meter manufactured by Kobunshi Keiki Co., Ltd. using a press sheet having a thickness of 1.0 mm. (7) Use a Ubbelohde viscometer to measure the solution viscosity as N
-Methyl-2-pyrrolidone, concentration (C) 0.0
A polymer solution of 25 g / dl was prepared, the drop time t of the polymer solution and the drop time t ₀ of the solvent were measured at 30 ° C., and the reduced viscosity was calculated using the following formula.

Η red = (1−t / t ₀ ) / C (8) The imidization ratio (Di) is calculated by the following formula by thermobalance measurement (TGA): Di = (1−Wmax / Wt) (where Wmax is Weight loss in the region below the thermal decomposition initiation temperature (actual measurement value), Wt represents the weight loss (theoretical value) when 100% imidization proceeded).

Reference Example 1 500 m equipped with a nitrogen introducing tube, a thermometer and a dropping funnel
A stirrer tip was placed in a 4-necked flask of 1 l, and under nitrogen, 12.587 g (42.78 mmol) of biphenyltetracarboxylic anhydride (hereinafter abbreviated as BTC) and 90 ml of N-methylpyrrolidone (hereinafter abbreviated as NMP). Charged. Attach a nitrogen inlet tube and put a stirrer chip into it 1
Dinitrodiphenyl ether (hereinafter abbreviated as DADPE) 5.711 g (2
(8.52 mmol), NMP 50 ml was charged, and DAD
A PE solution was prepared. The DADPE solution was added dropwise to the BTC slurry at room temperature over 45 minutes, and after completion of the addition, the mixture was stirred for 2 hours to obtain a polyamic acid solution. The ¹ H-NMR spectrum of the obtained polyamic acid is shown in FIG.

Reference Example 2 500 m equipped with a nitrogen introducing tube, a thermometer and a dropping funnel
Place a stirrer tip in a 4-necked flask of 1 l and put it under nitrogen under B
1.029 g of TC and 40 ml of NMP were charged. 0.35 g of DADPE, NMP under nitrogen in a 100 ml two-necked flask equipped with a stirrer tip with a nitrogen introduction tube attached.
A DADPE solution was prepared by charging 50 ml. Under ice cooling, the DADPE solution was added dropwise to the BTC slurry over 45 minutes, and after completion of the addition, the mixture was stirred for 2 hours to obtain a polyamic acid solution.

Example 1 40.17 g of sufficiently dried polytetramethylene glycol diamine having a number average molecular weight of 2620 was placed in a 1-liter four-necked flask, and the polyamic acid solution obtained in Reference Example 1 was stirred under nitrogen. Added in portions. The reaction was carried out at room temperature for 12 hours to obtain a viscous polymer solution. 0.95 g of pyridine and 0.61 g of acetic anhydride were added to this reaction solution, and the mixture was stirred at room temperature for 1 hour.
The imidization reaction was carried out for 6 hours to obtain a yellow polymer solution. The viscosity of the solution decreased slightly as the imidization proceeded.
The polymer solution obtained was poured into 1.5 l of water to isolate the polymer. The polymer is purified and dried by a conventional method.
6.8 g (85% yield) of elastomeric polymer was obtained.

The reduced viscosity measured in NMP was 0.44. The infrared absorption spectrum of the obtained polymer is shown in FIG. The obtained polymer was 0.5 mm at 270 ° C.
Was press-molded to a thickness of, and the physical properties were measured using this press sheet. The obtained sheet was transparent. The result of the dynamic viscoelasticity measurement is shown in FIG. From this, it can be seen that the polymer obtained in this example has a very high dynamic thermal stability. Further, the hardness (A) was as small as 68, the elastic modulus was 1.4 × 10 ⁸ dyn / cm ² , and the flexibility was excellent. Breaking strength and breaking elongation are 361 kg / cm ² ,
It was 550%. The thermal decomposition initiation temperature under nitrogen by TGA analysis was 300 ° C, the imidization ratio was 0.95, and the glass transition temperature (Tg) was -81.1 ° C. Small angle X
As a result of line measurement, the obtained polymer had a microphase-separated structure, and the domain period was 200 Å. Further, from the measurement of infrared absorption spectrum, absorption peaks at 1720 and 1775 cm ⁻¹ due to the presence of the imide ring were confirmed.

Example 2 32.85 g of sufficiently dried polypropylene glycol diamine having a number average molecular weight of 4350 was charged into a 1-liter 4-neck flask, and the polyamic acid solution obtained in Reference Example 2 was added in four portions under stirring in nitrogen. did. The reaction was carried out at room temperature for 18 hours to obtain a viscous polymer solution. The temperature was raised to 100 ° C. and polymerization was further performed for 2 hours and 130 ° C. for 2 hours to obtain a yellowish brown polymer solution. 10.23 g of pyridine in this reaction solution
And 50 ml of toluene were added, and the mixture was heated at 180 ° C. for 16 hours,
An imide reaction was carried out while azeotropically removing the produced water to obtain a yellow polymer solution. The viscosity of the solution decreased slightly as the imidization proceeded. 1.5 l of the obtained polymer solution
Was poured into water to isolate the polymer. The polymer was purified by a conventional method and dried to obtain 30.0 g (yield 74%) of an elastomeric polymer.

The reduced viscosity measured in NMP was 0.35. From the infrared absorption spectrum of the obtained polymer, 1722 and 1773c due to the presence of the imide ring
The absorption peak of m- ¹ was confirmed. The polymer obtained is 27
Press molding was carried out at 0 ° C. and physical properties were measured. Breaking strength 20
0 kg / cm ² , elongation at break 500%, hardness (A) 67,
The elastic modulus was 1.0 × 10 ⁸ dyn / cm ² , and the microdomain period by small-angle X-ray was 170 Å. Thermal decomposition start temperature under nitrogen by TGA analysis is 25
It was 0 degreeC, the imidation ratio was 0.90, and the glass transition temperature (Tg) was -69.0 degreeC.

[0038]

The segmented block copolymer of the present invention has excellent flexibility, transparency and mechanical strength,
It is useful as an elastic material having high heat resistance which is not found in conventionally known thermoplastic elastomers.

[Brief description of drawings]

FIG. 1 is a diagram showing an infrared absorption spectrum of polytetramethylene glycol diamine used in Example 1.

FIG. 2 is the polyamic acid ¹ obtained in Reference Example 1.
It is a figure which shows a H-NMR spectrum.

3 is a diagram showing the results of dynamic viscoelasticity measurement of the block copolymer of the present invention obtained in Example 1. FIG.

4 is a diagram showing an infrared absorption spectrum of the block copolymer of the present invention obtained in Example 1. FIG.

5 is a view showing TGA of the block copolymer of the present invention obtained in Example 1. FIG.

Claims (2)

[Claims] 1. The following general formula (1): (Here, n is an integer of 1 to 85 representing the degree of polymerization, and Z
Represents an aromatic group having 6 to 24 carbon atoms, and R represents 2 to 2 carbon atoms.
4 represents an aliphatic or aromatic group, and G has an average molecular weight of 50.
(Representing a polyoxyalkylene chain of 0 to 5000) and having a reduced viscosity of 0.1 to 13.0d measured at 30 ° C. in N-methyl-2-pyrrolidone.
A segmented block copolymer having an imidization ratio (Di) of 0.5 or more, which is 1 / g. 2. A. The following general formula (2): (Wherein G represents a polyoxyalkylene chain having a number average molecular weight of 500 to 5000) and b. The following general formula (3): (Wherein R represents an aliphatic or aromatic group having 2 to 24 carbon atoms) and an aromatic diamine represented by the following general formula (4): (Wherein Z represents an aromatic group having 6 to 24 carbon atoms), which is obtained by reacting an aromatic tetracarboxylic acid anhydride represented by the reaction with an acid anhydride group-terminated polyamic acid. The method for producing a segmented block copolymer according to claim 1, wherein the block copolymer is imidized.