FR2595362A1 - AROMATIC POLYAMIDES AND POLYBENZOXAZOLES HAVING DIPHENYLHEXAFLUOROPROPANE UNITS, AND PROCESS FOR THE PREPARATION THEREOF - Google Patents

Abstract

THE INVENTION RELATES TO AN AROMATIC POLYAMIDE. ACCORDING TO THE INVENTION, IT IS REPRESENTED BY THE GENERAL FORMULA (CF DRAWING IN BOPI) IN WHICH R IS A DIVALENT AROMATIC GROUP AND N IS AN ENTIRE NUMBER FROM 1 TO 200. THE INVENTION APPLIES IN PARTICULAR TO THE PREPARATION OF RESINS OF STRONG MECHANICAL RESISTANCE, THERMORESISTANT AND EASY TO SHAPE.

Description

The present invention relates to a group of novel polyamides

  aromatic compounds having units derived from diphenylhexafluoropropane and a process for their preparation, and a group of aromatic polybenzoxazoles derived from the novel polyamides. Certain aromatic polyamides are known as

  resins of high mechanical and thermal

  resistant. However, aromatic polyamide resins

  Known materials are not practical for shaping because they lack moldability and also because they are soluble only in limited and special solvents such as strong mineral acids that are corrosive and pose many problems. problems in putting spinning or molding operations into practice

solution.

  Certain aromatic polybenzoxazoles such as those described in Macromol. Chem., Vol. 83 (1965), 167, are excellent in mechanical properties such as tensile strength, flexural strength and impact resistance, heat resistance represented by heat distortion temperature, and thermal resistance. thermal decomposition temperature, electrical properties such as arc resistance and dielectric loss,

  flame resistance and dimensional stability.

  However, the known aromatic polybenzoxazoles can hardly be used in industrial resins because they can not be melt-molded and are not soluble in solvents which can be used in practice. JP 42-19272 proposes obtaining a polybenzoxazole in a desired form by first casting a solution of a polyamide to the desired shape and then converting the polyamide to polybenzoxazole. However, this method is not suitable for practical applications given the problems relating to solvents

  limited aromatic polyamides.

  Even if a polymer has attractive properties, the polymer is of little value as an industrial plastic unless it has good moldability and / or solubility in a process.

  solvent of low price and practical to manipulate indus-

  -annually. It is unlikely to obtain aromatic polyamides and polybenzoxazoles having a melt moldability because of their high melting or softening temperatures. As a result, solubilities in common solvents become of paramount importance. In general, it is effective, to improve the moldability or solubility of a polymer, to produce some disorder of the molecular structure

  introducing a bulky substituent or by copolymerizing

  tion. However, it often happens that such a modification

  of a polymer is accompanied by a degradation of

  thermoresistance and possibly other characteristics

of the original polymer.

  The subject of the present invention is new

  aromatic polyamides soluble in various solvents.

  organic and possessing excellent heat resistance

  and good mechanical properties.

  Another subject of the present invention is a process for the preparation of aromatic polyamides according to the invention. Another subject of the present invention is new polybenzoxazoles derived from aromatic polyamides

  according to the invention, soluble in various organic solvents.

  The above objectives were achieved by discovering that a group of aromatic polyamides derived from 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, i.e. a compound of the following formula, were readily soluble in various organic solvents and that a group of polybenzoxazoles derived from these aromatic polyamides was also soluble in various organic solvents.

H2N CF3 NH-

Q cQ3

HO '... H

H 0 e <H

C CF3

  More specifically, the invention relates to aromatic polyamides represented by the general formula (1)

CF O

CHNi NH R (1)

0 H0 | OH

  CF3 n wherein R is a divalent aromatic group, and n

is an integer from I to 200.

  According to the invention, an aromatic polyamide represented by the general formula (1) is prepared by

  reaction of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoro-

  propane with a dicarboxylic acid represented by the general formula (2), a dicarboxylic acid dihalide represented by the general formula (3) or a dicarboxylic acid diester represented by the general formula (4):

HO-C-R-C-OH (2)

  wherein R is a divalent aromatic group;

P

(3)

X-C-R-C-X (3)

  wherein R is a divalent aromatic group and X is a halogen atom; 0 0

R'O-C-R-C-OR '(4)

  wherein R is a divalent aromatic group and

  R 'is an alkyl group or a phenyl group.

  Aromatic polyamides according to the invention are easily soluble in various common solvents and therefore can easily be made into various forms from solutions. In addition, these polyamides are excellent in their heat resistance and have good mechanical properties. As a result, these polyamides have

  some value as industrial materials.

  On the other hand, these polyamides can easily be converted to the corresponding polybenzoxazoles which are soluble in various organic solvents by a reaction.

cyclisation.

  Using aromatic polyamides represented

  by the general formula (1), the present invention

  polybenzoxazoles represented by the general formula (5):

N C F3 N

  CF3 in which R is a divalent aromatic group and n

is an integer from 1 to 200.

  These polybenzoxazoles are also soluble in a variety of common organic solvents and therefore can easily be made into various forms from solutions. In addition, these polybenzoxazoles are excellent in their heat resistance and their mechanical properties. As a result, these polybenzoxazoles have a

  certain value as industrial materials.

  To prepare an aromatic polyamide according to

  the invention from 2,2-bis (3-amino-4-hydroxyphenyl) -

  hexafluoropropane (which will be abbreviated as BAHPH-HFP) by reaction with an aromatic dicarboxylic acid, any known dicarboxylic acid represented by the general formula (2) can be used. Examples of suitable dicarboxylic acids for the practice of the invention are given below: isophthalic acid, terephthalic acid, 4, 4'-biphenyldicarboxylic acid, acid

  biphenyl ether-4,4'-dicarboxylic acid, benzophenone

  4,4'-dicarboxylic acid, benzosulfone-4,4'-dicarboxylic acid,

  2,6-naphthalene dicarboxylic acid, diphenylmethane

  4,4'-dicarboxylic acid, 4,4'-isopropylidenediphenyl-1,1'-

  dicarboxylic acid and 4,4'-hexafluoroisopropylidene

diphenyl-1,1'-dicarboxylic acid.

  Alternatively, it is possible and quite practical to use a dicarboxylic acid dihalide which may be one of the known compounds represented by the general formula (3). Preferable examples are dichlorides of the above-named ten types of dicarboxylic acids. Alternatively again, it is possible to use a diester of the dicarboxylic acid which can be any

  known compound represented by the general formula (4).

  Preferable examples are diphenyl esters of the ten

  above-mentioned types of dicarboxylic acids.

  It is optional to use a mixture of two or more types of dicarboxylic acids or dicarboxylic acid dihalides or dicarboxylic acid diesters to thereby obtain a copolymer in the form of a

  aromatic polyamide according to the invention.

  In the case of the reaction of BAHPH-HFP with a dicarboxylic acid represented by the general formula (2), the reaction is carried out in a suitable organic solvent such as, for example, N, N-dimethylformamide, N, N-dimethylacetamide or N-methyl-2-pyrrolidone at a temperature between room temperature and the boiling point of the solvent employed. When a dicarboxylic acid dihalogenide represented by the general formula (3) is used instead of the acid, the reaction is also carried out in a similar organic solvent, and in this case the appropriate temperature of the reaction is included between about -100 ° C. and about 50 ° C. A similar organic solvent is also used in the case of the reaction of BAHPH-HFP with a dicarboxylic acid diester represented by the general formula (4) and in this case, the appropriate temperature of the reaction is

  between about 50 C and about 300 C.

  A polybenzoxazole according to the invention, represented by the general formula (5), is obtained by subjecting a polyamide according to the invention to a dehydration and cyclization reaction. This reaction is itself well known. In general, the reaction is accomplished by heating the polyamide for a sufficient period of time at a temperature of between about 100 ° C. and about 500 ° C. It is optional to heat the polyamide in the presence of a dehydrating agent such as, for example polyphosphoric acid to effect the dehydration and cyclization reaction at a relatively low temperature. It is also optional to carry out the reaction under reduced pressure because of the possibility of carrying out the reaction at a

relatively low temperature.

  Another process for preparing a polybenzoxazole according to the invention comprises reacting BAHBH-HFP with an aromatic dicarboxylic acid represented by the general formula (2) in polyphosphoric acid. The reaction is carried out at 10-250 ° C for tens of minutes to several hours. This reaction directly gives a polybenzoxazole.

EXAMPLE 1

  In a 50 ml three-necked flask having a nitrogen gas inlet, 0.915 g of BAHPH-HFP was dissolved in 5 ml of dimethylacetamide. The solution was frozen using a dry ice bath and acetone, and 0.508 g of isophthalic acid dichloride was placed in the flask. Thereafter, the bath was changed to an ice bath and slight stirring was begun to force the frozen solution to gradually melt. Stirring was continued for 5 hours while maintaining a nitrogen gas atmosphere in

  the ball. As a result, a polymer was obtained.

  By infrared absorption spectrum analysis, the polymer exhibited absorption bands at 1650 cm -1 -1 and 1600 cm -1 which are characteristic of the acid amides. Elemental analysis of this polymer gave

the following result.

  Calcd. (%): C 55.66, H 2.84, N 5.64 Experiment (%): C 55.46, H 2.61, N 5, 78 Therefore, it was confirmed that the obtained polymer was a polyamide represented by the formula

next (6).

(0 o IlI

CHN CF3 NHC (6)

HO OH

  CF3 n In sulfuric acid, the inherent viscosity * Linh of this polyamide was 0.08 dl / g at 30 C.

  polyamide was, for example, soluble in dimethyl

  formamide, pyridine, 1-methyl-2-pyrrolidone,

  dimethyl sulfoxide, tetrahydrofuran and acetone.

EXAMPLE 2

  The polyamide prepared in Example 1 was placed in a glass test tube and heated at 250 ° C. for 20 hours while the pressure in the test tube

  was kept reduced to 1.33 mbar or less.

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  By infrared absorption spectrum analysis after the heat treatment above, the polymer has

  showed an absorption band at 1620 cm 1, characterized

  tick of oxazole. Elemental analysis of the heat-treated polymer gave the following result. Calculation (%): C 60.01, H 2.19, N 6.08

  Experiment (%): C 60.13, H 2.26, N 6.31.

  Therefore, it was confirmed that the heat-treated polymer was a polybenzoxazole represented

by the following formula (7).

C $ 8 JY C7JO C, J (7)

CF3

/not

EXAMPLE 3

  By the same method as in Example 1,

  react BAHPH-HFP with 2,2-bis (4-chlorocarbonylphenyl) -

  hexafluoropropane to obtain a polymer.

  By infrared absorption spectrum analysis, the polymer showed absorptions at 1650 cm -1 and 1600 cm -1. Elemental analysis of this polymer gave

the following result.

Calculation (%): C 53.20, H 2.51, N 3.88

  Experiment (%): C 53.17, H 2.34, N 3.91.

  Therefore, it was confirmed that the resulting polymer was a polyamide represented by the formula

next (8).

J.J. J.J.

He HN 3 NH CF3

0 HO; 0D -} H C Q (8)

HO 1i CF3 CF3 n

EXAMPLE 4

  The polyamide prepared in Example 3 was heated in a glass test tube at 250 ° C. for 30 hours while the pressure in the test tube was maintained.

reduced to 1.33 mbar or less.

  The heat-treated polymer exhibited infrared absorption at 1620 cm 1 and elemental analysis

  of this polymer gave the following result.

  Calculation (%): C 55.99, H 2.06, N 4.66 Experiment (%): C 55.70, H 2.04, N 4, 98 Therefore, it was confirmed that the heat treated polymer was a represented polybenzoxazole

by the following formula (9).

C C C

C $ Js C> IJ C 4 O <(9)

CF3 CF

  The heat resistance of this polybenzoxazole was examined by thermogravimetric analysis. In the air, the polymer began to decompose at about 415 C and

  presented a weight loss of 10% at 520 C.

  This polybenzoxazole was soluble, for example,

  in o-chlorophenol, pyridine, 1-methyl-2-

  pyrrolidone and dimethylacetamide.

9RCor 24

EXAMPLE 5

  In a 100 ml flask connected to a source of nitrogen gas and with a reflux condenser, a mixture of 1.830 g (5 millimoles) of BAHPH-HFP, 1.290 g (5 millimoles) of acid was heated to 100 [deg.] C. 4,4'-Oxidibenzoic acid, 10 ml

  of N-methylpyrrolidone, 2.5 ml of pyridine, 3.1 g (10 milligrams

  moles) of triphenyl phosphite and 0.5 g of lithium chloride in a nitrogen gas atmosphere and

  stirring for 6 hours under the same conditions.

  Then the reaction liquid was slowly poured

  in a large amount of water to precipitate a white polymer.

  The polymer obtained had infrared absorptions at 1650 cm -1 and 1600 cm -1 and the analysis

  Elemental of this polymer gave the following result.

Calc (%): C 59.19, H 3.08, N 4.76

  Experiment (%): C 59.09, H 3.13, N 4.85.

  Therefore, it was confirmed that this polymer was a polyamide represented by the following formula (10). In sulfuric acid, the inherent viscosity

  of this polyamide was 0.1 dl / g at 30 C.

(10)

CH NJXHC Y O / N-C

HO

n CF3

EXAMPLE OF COMPARISON

  For comparison with the polyamides (6), (8) and (10) of Examples 1, 3 and 5, two types of known polyamides represented by formulas (i) and

  (ii) following, each by a known method.

2S95362

CH3 (i) CH3 n

- 3

q ilN H (ii)

EH Q NHC

  The polyamide (i) was prepared by reaction of 2,2-bis (3-amino-4-hydroxyphenyl) propane with isophthalic acid chloride in dimethylacetamide. The

  polyamide (ii) was prepared by reaction of 4,4'-diamino

  -3,3'-dihydroxydiphenyl with acid chloride

  isophthalic in dimethylacetamide.

  The solubilities of the new polyamides (6), (8) and (10) and the known polyamides (i) and (ii) in several types of organic solvents have been shown as shown in the following table, where the evaluation marks

  A to 0 indicate the following results, respectively.

A: quickly dissolved.

B: dissolved.

C: partially dissolved.

D: insoluble.

  Polyamide Solvent (6) (8) (10) (i) (ii) pyridine A A A D dimethylformamide A A C D N-methylpyrrolidone A A A A methanol C C B D D acetone A A C D methyl ethyl ketone C C B C D ethyl acetate C C B D D tetrahydrofuran A A A C D

EXAMPLE 6

  This example relates to the preparation of a polybenzoxazole according to the invention, by a method in one

only stage.

  In a 100 ml three-necked flask connected to a source of nitrogen gas, and with a reflux condenser, a mixture of 1.83 g of BAHPH-HFP, 0.83 g of isophthalic acid and from 60 g of 116% polyphosphoric acid to a reaction at 200 ° C. for 4 hours in a nitrogen gas atmosphere with continuous stirring. Then, the reaction liquid was poured into a large amount of water to precipitate a polymer. This polymer was washed with a dilute aqueous solution of sodium carbonate and dried. The polymer obtained had a characteristic infrared absorption at 1620cm-1 of the oxazoles, and the elemental analysis of this polymer gave the following result. Calculation (%): C 60.01, H 2.19, N 6.08

  Experiment (%): C 59.78, H 2.20, N 6.15.

  Therefore, it was confirmed that the resulting polymer was polybenzoxazole represented by

  formula (7) shown in Example 2.

EXAMPLE 7

  This example also relates to the preparation of a polybenzoxazole according to the invention, by a method of

only one stage.

  Using the same apparatus as in Example 6, a mixture of 1.83 g of BAHPH-HFP, 1.29 9 of 4,4'-diphenyl dicarboxylic acid and 60 g of polyphosphoric acid at 116 ° C. % was subjected to a reaction at C for 4 hours in a nitrogen gas atmosphere with continuous stirring. Then, the reaction liquid was poured into a large amount of water to precipitate a polymer, which was washed and dried in the same way

than in Example 6.

  The polymer obtained exhibited an infrared absorption at 1620 cm 1, and the elemental analysis of this

  polymer gave the following result.

Calculation (%): C 63.05, H 2.55, N 8.69

  Experiment (%): C 62.88, H 2.56, N 8.96.

  Therefore, it was confirmed that this polymer was a polybenzoxazole represented by the formula

next (11).

(11)

N CF3

O C QC C 0

  CF3 n In sulfuric acid, the inherent viscosity

  -Vinh of this polybenzoxazole was 0.08 dl / g at 30 C.

  The heat resistance of this polymer was examined by thermogravimetric analysis. In the air, the polymer has

2595362 -

  started to decompose at about 420 C and showed% weight loss at 535 C. This polybenzoxazole was soluble for example in ochlorophenol, pyridine

and 1-methyl-2-pyrrolidone.

2595362

R E V E N D IC A T IO N S

___________________________

  1.- Aromatic polyamide, characterized in that it is represented by the general formula (1)

\ CHN> _ δ <3 NHÉ-R (1)

HO7 '-

CF3

  wherein R is a divalent aromatic group, and n

is an integer from 1 to 200.

  2. Aromatic polyamide according to claim 1,

  characterized in that R is -C6H4-.

  3. Aromatic polyamide according to claim 1,

  characterized in that R is -C6H4-C (CF3) 2-C6H4-.

  4. Aromatic polyamide according to claim 1,

  characterized in that R is -C6H4-O-C6H4CO-.

  5. Process for the preparation of an aromatic polyamide

  tick, characterized in that it comprises the steps of

  reacting 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoro-

  propane with a selected aromatic dicarboxylic compound

  in the group consisting of dicarboxylic acids

  characterized by the general formula (2), dicarboxylic acid dihalides represented by the general formula (3) and dicarboxylic acid diesters represented by the general formula (4):

0 0

IHO-C-R-C-OH (2) I

HO-C-R-C-OH (2)

  wherein R is a divalent aromatic group, O O ti fi

X-C-R-C-X (3)

  wherein R is a divalent aromatic group, and X is a halogen atom,

R'O-C-R-C-OR '(4)

  wherein R is a divalent aromatic group and R '

  is an alkyl group or a phenyl group.

  6. Process according to claim 5, characterized in that the abovementioned aromatic dicarboxylic compound

  is a dicarboxylic acid selected from the group consisting of

  both isophthalic acid, terephthalic acid, acid

  4,4'-biphenyldicarboxylic acid, 4,4'-biphenyl ether

  dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid,

  benzosulphone-4,4'-dicarboxylic acid, 2,6-naphthalene

  dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, 4,4'-isopropylidenediphenyl-1,1'-dicarboxylic acid and

  4,4'-hexafluoroisopropylidenediphenyl-1,1'-

  dicarboxylic. 7. A process according to claim 5, characterized in that said aromatic dicarboxylic compound is a dicarboxylic acid dichioride selected from the group consisting of isophthalic acid dichloride, terephthalic acid dichloride, acid dichloride

  4,4'-bisphenyldicarboxylic acid, biphenyl acid dichloride

  4,4'-dicarboxylic ether, benzophenone acid dichloride

  4,4'-dicarboxylic acid, benzosulfone-4,4'-dichloride

  dicarboxylic acid, 2,6-naphthalene acid dichloride

  dicarboxylic acid, 4,4'-diphenylmethane dichloride

  dicarboxylic acid, 4,4'-isopropylidene acid dichloride

Diphenyl-1,1'-dicarboxylic acid and 4,4'-dichloride

  hexafluoroisopropylidènediphényl-1,1'-dicarboxylic acid.

  8. A process according to claim 5, characterized in that the aromatic dicarboxylic compound mentioned above is a diester of the dicarboxylic acid selected from the group consisting of diphenyl isophthalate, diphenyl terephthalate, diphenyl 4,4'-biphenyldicarboxylate, diphenyl biphenyl ether-4 , 4'-dicarboxylate, diphenyl

  benzosulphone-4,4'-dicarboxylate, diphenyl-2,6-naphthalene

  dicarboxylate, diphenyl diphenylmethane-4,4'-dicarboxylate, diphenyl 4,4'isopropylidene diphenyl-1,1'-dicarboxylate

  and 4,4'-hexafluoroisopropylidenediphenyl-1,1'-diphenyl

  dicarboxylate. 9. Polybenzoxazole, characterized in that it is represented by the general formula (5):

N CF3 NF

N 13 N (5)

  in which R is a divalent aromatic group and n

is an integer from 1 to 200.

  Polybenzoxazole according to claim 9,

  characterized in that R is -C6H4-.

  11. Polybenzoxazole according to claim 9,

  characterized in that R is -C6H4-O-C6H4-.

  12. Polybenzoxazole according to claim 9,

  characterized in that R is -C6H4-C (CF3) 2-C6H4-.

  13. A process for the preparation of a polybenzoxazole, characterized in that it comprises the step of subjecting an aromatic polyamide represented by the general formula (1) to a dehydration and cyclization reaction: o HC -R n (1) ) in which R is a divalent aromatic group and n

is an integer from 1 to 200.

CF3