JPH0742355B2 - Thermoplastic aromatic polyamide-imide copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention provides a molded article which has good thermal stability and fluidity particularly in the temperature range of 300 to 400 ° C., and which can be injection-molded and has desirable characteristics. The present invention relates to a novel thermoplastic aromatic polyamideimide copolymer that can be given (hereinafter, polyamideimide is abbreviated as PAI).

<Prior Art> By polycondensing an aromatic tricarboxylic acid anhydride or a derivative thereof and an aromatic diamine or a derivative thereof,
It is already well known that an aromatic PAI having excellent heat resistance is generally obtained (for example, Japanese Patent Publication No. 42-15637).
JP-B, JP-B-44-19,274, JP-B-45-2,397, JP-B-49-4,077, JP-B-50-33,120, etc.).

<Problems to be Solved by the Invention> However, aromatic PAIs that have been generally proposed so far have the thermal stability during melt molding and the heat stability during melt molding when they are intended to be used as melt molding materials. It was not always satisfactory in terms of fluidity and total balance of physical properties of the melt-molded product.

For example, a general formula synthesized from trimellitic anhydride chloride and 4,4'-diaminodiphenyl ether Polyamide imide represented by
Although described in Japanese Patent No. 5,637), the heat resistance is excellent, but since the flow initiation temperature and the thermal decomposition temperature are too close to each other, substantially no melt molding is possible.

Also, a general formula synthesized from trimellitic anhydride chloride and 4,4′-diaminobenzanilide Although the aromatic polyamideimide represented by the formula (3) also has excellent heat resistance, it is difficult to melt-mold it because the flow starting temperature is higher than the decomposition temperature.

Further, trimellitic anhydride chloride and 3,3′-diaminobenzanilide, 3,4′-diaminobenzanilide, 4,3′-diaminobenzanilide and other m-amide group-containing diamines (hereinafter, these diamines are (Generically referred to as m-aramiddiamine) Although the aromatic polyamideimide represented by the formula (1) can be melt-molded, it has poor toughness and the physical properties (particularly bending strength) of the molded product do not necessarily reach a satisfactory level.

Therefore, the present inventors have solved these problems of PAI and have good melt moldability by combining good thermal stability and fluidity in the temperature range of 300 to 400 ° C. Aromatic PAI with well-balanced physical properties
As a result of earnest studies aimed at obtaining the above, it was found that it is extremely effective to copolymerize a specific aramiddiamine with an aromatic diamine having a specific aryl ether bond, and arrived at the present invention.

<Means for Solving Problems> That is, the present invention is Structural unit of Structural units and The ratio of each structural unit is such that B + C is substantially 1 mol relative to Al mol, and B / C is 10 to 95 mol% / 90.
To 5 mol% in a N-methyl-2-pyrrolidone solvent, the polymer concentration is 0.5% by weight, and the logarithmic viscosity measured at 30 ° C. is 0.20 to 0.92. Polymer. (However, X in the above formula is R represents an alkyl group having 1 to 4 carbon atoms or a halogen group, a represents 0, 1 or 2, and b represents an integer of 0 or 1 to 4. )
Is provided.

The thermoplastic polyamide-imide copolymer of the present invention is mainly composed of 3 units shown by A, B and C above.

A'unit when the imide bond in the above A unit remains in the amic acid bond state as the ring-closing precursor Is a part of the A unit, for example, 50 mol% or less, preferably 30
The case where the amount is less than or equal to mol% is also included in the scope of the present invention.

As a specific example of the B unit, for example, Etc. and side chain substituted derivatives thereof, and the like. Is preferred.

The C unit is a divalent diphenylamide group containing at least one m-phenylene, and specific examples thereof include Can be given.

In each of the above-mentioned units in the polyamide-imide copolymer of the present invention, the ratio of the component A and the component (B + C) is equimolar,
It has a structure in which the component and the B component or the C component are alternately connected. And B component and C as diamine residue
The composition ratio of the components is such that B / C is 10 to 95 mol% / 90 to 5 mol%, preferably 20 to 90 mol% / 80 to 10 mol%. When the proportion of the B unit is 95 mol% or more in the B + C unit, the fluidity of the resulting copolymer upon melting is significantly lowered, and melt molding is substantially difficult, which is not preferable. Further, if the proportion of B units is 10 mol% or less in B + C units, the toughness of the copolymer is lowered and the strength is greatly lowered, which is not preferable.

The PAI copolymer of the present invention can be produced by using any of a number of general production methods proposed so far, and among them, the following two methods are representative as highly practical. Can be mentioned.

(1) Isocyanate method: a method of reacting an aromatic diisocyanate with an imidecarboxylic acid synthesized from aromatic tricarboxylic acid anhydride and / or aromatic tricarboxylic acid anhydride / aromatic diamine (2/1 molar ratio) (for example, a special method) JP-B-44-19,274, JP-B-45-2,397,
Japanese Patent Publication No. 50-33,120, etc.).

(2) Acid chloride method: A method in which an aromatic tricarboxylic acid anhydride chloride and an aromatic diamine are reacted (for example, Japanese Patent Publication No. Sho 42-15637).

Among the above two methods, the acid chloride method has the advantages that the raw material is relatively easy to procure, and that low-temperature solution polymerization can easily obtain highly polymerized PAI with excellent linearity (low branching structure). Is the most recommended manufacturing method. Here, the production example of the PAI copolymer of the present invention by the acid chloride method will be described in more detail as follows. That is, 1 mol of an aromatic tricarboxylic acid anhydride monochloride and 0.9 to 1.1 mol of a mixed diamine consisting of 10 to 95 mol% of an aromatic diamine of the following formula (I) and 90 to 5 mol% of an aromatic diamine of the following formula (II). And are dissolved in an organic polar solvent.

(However, in the formula, R is an alkyl group having 1 to 4 carbon atoms or a halogen group, a is 0, 1 or 2, b is an integer of 0 or 1 to 4, and X is Indicates. ) Next, after mixing under a temperature condition of -20 to 80 ° C for about 0.5 to 1 hour, a hydrogen chloride scavenger of 0.8 to 1.2 is added if necessary.
When the polymerization reaction rate is accelerated by adding about a mole, the polymerization reaction is completed at room temperature at a reaction time of 0.5 to 10 hours. The polymer formed at this stage is such that most (for example, 50 to 100%) of the A units of the PAI copolymer of the present invention are amide / amic acid units of the ring closure precursor. It is converted into a so-called polyamide-amic acid. The organic polar solvent used in this first step is N
-N-N-dialkylcarboxylic acid amides such as N-dimethylacetamide and N-N-diethylacetamide,
Heterocyclic compounds such as N-methyl-2-pyrrolidone and tetrahydrothiophene-1-1.1-dioxide, phenols such as cresol and xylenol, and particularly N-methyl-2-pyrrolidone and N.N-dimethyl. Acetamide is preferred. Further, the hydrogen chloride scavenger added to the above-mentioned first step as necessary is an aliphatic tertiary amine such as trimethylamine, triethylamine, tripropylamine, tributylamine, pyridine, lutidine, collidine or quinoline. Cyclic organic bases, organic oxide compounds such as ethylene oxide and propylene oxide, and the like.

The polyamide-amic acid obtained in the above-mentioned first step is then converted into the polyamide-imide copolymer of the present invention in the second dehydration ring-closing step. The dehydration ring-closing operation is carried out by either liquid-phase ring-closing in a solution or solid-phase thermal ring-closing by heating with a solid. There are two types of liquid phase ring closure: a liquid phase chemical ring closure method using a chemical dehydrating agent and a simple liquid phase thermal ring closure method.
The chemical ring closure method is carried out by using an aliphatic anhydride such as acetic anhydride or propionic anhydride, or a chemical dehydrating agent such as P ₂ O _{5 at} a temperature of 0.
It is carried out at -120 ° C (preferably 10-60 ° C). Also,
The liquid phase thermal cyclization method uses a polyamide-amic acid solution of 50 to 400
It is carried out by heating to ℃ (preferably 100 to 250 ℃). At that time, it is more effective to use an azeotropic solvent useful for removing water, such as benzene, toluene, xylene, and chlorbenze together. Solid-phase thermal ring closure is the first
It is carried out by isolating a polyamide / amic acid polymer from the polyamide / amic acid solution obtained in the step and heat-treating it in a solid state. As the precipitating agent for isolating the polyamide / amic acid polymer, a liquid which is miscible with the reaction mixture solvent but in which the polyamide / amic acid itself is insoluble, such as water or methanol, is adopted. The solid-phase heat treatment is usually selected from the conditions of 150 to 350 ° C. and 0.5 to 50 hours so as to secure the desired ring closure ratio and fluidity during melting. It should be noted that if the treatment is carried out for a long time in the range of 250 to 350 ° C., the polymer itself tends to form a three-dimensional crosslinked structure and the fluidity at the time of melting tends to be significantly lowered.

In addition, the specific examples of the aromatic diamines (I) and (II) are the amino groups (-NH 2) on both sides of the divalent aromatic residues shown as specific examples of the B unit and the C unit of the present invention.
₂ ) is displayed with the mark attached.

Specific examples of the aromatic diamine represented by the above general formula (I) are shown by the structural formulas below.

Specific examples of the aromatic diamine represented by the general formula (II) are shown below by structural formulas.

It is an object of the present invention to provide a manufacturing method detailed above.
Although a PAI copolymer is obtained, the melt processability and physical properties of PAI, which produces other copolymerized components other than the components constituting the A unit, B unit and C unit, in the reaction system are significantly reduced. It is possible to combine and copolymerize in a quantitative range that does not exist, and it is included in the scope of the present invention.

The aromatic PAI copolymer of the present invention has a structure in which most of the imide units are retained in a partially opened amide acid bond, but most of them have a closed ring structure, and N-methyl-2-
Pyrrolidone solvent, polymer concentration 0.5 wt%, logarithmic viscosity (ηinh) value measured at 30 ℃ 0.20 ~ 0.92, preferably
It is a polymer having a high degree of polymerization of 0.25 to 0.92 and can be utilized in various applications as described below.

Compression molding is carried out after dry blending the PAI copolymer powder of the present invention with a different polymer, an additive, a filler, a reinforcing agent, etc., if necessary, and usually under conditions of 300 to 400 ° C. and a pressure of 50 to 500 kg / cm ² . Will be carried out. In addition, extrusion molding and injection molding, the PAI copolymer of the present invention is a dry blend of different polymers, additives, fillers, reinforcing agents and the like as required, or pellets pelletized by applying this to an extruder. It is supplied to an extruder or an injection molding machine and is carried out under a temperature condition of 300 to 400 ° C. In particular, the aromatic PAI copolymer of the present invention is 300-
It has an outstanding balance of thermal stability and flow characteristics at 400 ° C discharge, and is useful for extrusion molding and injection molding. Further, by subjecting the molded product obtained by heat-melting and molding the PAI copolymer of the present invention to a heat treatment under further high temperature conditions, a molded product having further improved physical properties such as heat distortion temperature, tensile strength, bending strength and frictional wear characteristics can be obtained. Obtainable. The heat treatment conditions include a temperature of the molded body of 200 ° C. or higher and a glass transition temperature of the molded body or lower, particularly 220 ° C. or higher, and a temperature of (glass transition temperature −5 ° C.) or lower of the molded body for 5 hours or longer, particularly 10 hours or longer. It is suitable to heat. If the heat treatment temperature exceeds the glass transition temperature of the molded body, the molded body tends to be deformed during the heat treatment and impairs its practical use, which is not preferable. The apparatus for carrying out this heat treatment is not particularly limited, but an ordinary electrically heated oven can sufficiently achieve the purpose.

For film and fiber manufacturing applications, the post-polymerization solution can be applied to a dry or dry-wet casting process,
If necessary, a suitable additive may be added to the isolated polymer to be melt-molded. The laminated plate is obtained by impregnating a cloth or mat composed of glass fiber, carbon fiber, asbestos fiber, etc. with a polymer solution and then pre-curing by drying / heating to obtain a prepreg, which is 200 to 400 ° C. ,
It is produced by pressing under the condition of 50 to 300 kg / cm ² .

For use as a coating material, a different solvent may be added to and mixed with the polymerized solution, if necessary, and then the concentration may be adjusted for practical use.

If necessary, the composition of the present invention may contain the following fillers in an amount of 70% by weight or less. (A)
Abrasion resistance improver: Graphite, carborundum, silica powder, molybdenum disulfide, fluorine resin, etc. (b) Reinforcing agent: glass fiber, carbon fiber, boron fiber, silicon carbide fiber, carbon whiskers, asbestos fiber, asbestos ,
(C) Flame retardant improver: antimony trioxide, magnesium carbonate, calcium carbonate, etc. (d) Electrical property improver: clay, mica, etc. (e) Tracking resistance improver: asbestos, silica, graph Ait etc. (f)
Acid resistance improver: barium sulfate, silica, calcium metasilicate, etc. (g) Thermal conductivity improver: metal powder such as iron, zinc, aluminum, copper, etc. (h) Others: glass beads, glass spheres, calcium carbonate, It includes synthetic and natural compounds that are stable at 300 ° C or higher, such as alumina, talc, diatomaceous earth, hydrated alumina, mica, silas balloon, asbestos, various metal oxides, and inorganic pigments.

<Example> Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The logarithmic viscosity (η
The value of inh) is measured in a N-methyl-2-pyrrolidone solvent at a polymer concentration of 0.5% and a temperature of 30 ° C. The glass transition temperature (Tg) is 1B type manufactured by Perkin Elmer.
It measured using the DSC apparatus.

The various physical properties were measured according to the following methods.

Bending strength (FS) …… ASTM D790 Flexural modulus (FM) …… ASTM D790 Heat distortion temperature (HDT) …… ASTM D-648-56 (18.56kg / cm ² ) Examples 1-4 and Comparative Examples 1- 2 Internal volume with a stirrer, thermometer and nitrogen gas inlet tube 5
After the 4.4'-diaminodiphenyl ether (DDE) and 3.4'-diaminobenzanilide (3.4'-DABA) were charged in a glass separable flask of No. 3 with the composition shown in Table 1, anhydrous N. N-dimethylacetamide (DMAC)
3,000 g was added and stirred to obtain a uniform solution. The mixture was cooled in an ice bath and anhydrous trimellitate motochloride (TMA).
C) 589.6 g (2.8 mol) was added portionwise at a rate such that the internal temperature did not exceed 30 ° C. Then, after stirring for 2 hours as it is,
350 ml of pyridine and 750 ml of acetic anhydride (about 7.5 mol) were added, and the reaction was terminated by stirring for 30 minutes.

Next, the polymerization-terminated liquid is gradually poured into water under high-speed stirring to precipitate the polymer into powder, which is thoroughly washed with water / dehydrated, and then in a hot air dryer at 150 ° C. for 5 hours, followed by 200 times. After drying at 0 ° C. for 3 hours, a polymer powder having a logarithmic viscosity and a glass transition temperature (Tg) as shown in the column of properties at the end of polymerization in Table 1 was obtained.

The theoretical structural unit formula and molecular formula of the copolymer obtained in this Example 1 are as follows, and have a structure in which A units and B or C units are alternately linked, and the copolymer The elemental analysis results showed good agreement with the theoretical values as shown in Table 2.

A / B / C = 2.80 / 2.10 / 0.70 (molar ratio) = 100/75/25 (mol%) Moreover, the elemental analysis results of the polymers of Examples 2, 3 and 4 also showed good agreement with the theoretical values. .

Next, a tetrafluoroethylene resin (“Aflon Polymist F” manufactured by Asahi Glass Co., Ltd.) was added to the obtained copolymer powder as an anti-burn agent.
-5 ") 2 wt% was added, and then the mixture was fed to a Brabender Plastograph extruder (processing temperature 300 to 360 ° C) to obtain a melt extruded pellet.

However, the polymer powder of Comparative Example 1 had an abnormally high melt viscosity and could not be pelletized by melt-kneading / extrusion.

Next, the pellets obtained were processed by a small injection molding machine (processing temperature 300
~ 350 ℃, injection pressure 1,400 ~ 1,700kg / cm ² ) to create a test piece, put the molded test piece in a hot air dryer 200 ℃
Heat treatment was carried out for 24 hours at 250 ° C for 24 hours, and subsequently at 260 ° C for 24 hours. Subsequently, physical properties were measured, and the results as shown in the column of characteristics of the molded product after heat treatment in Table 1 were obtained.
The molded product obtained in Comparative Example 2 was more brittle and had a lower bending strength than the molded products of Examples 1 to 4.

Examples 5 to 7 and Comparative Example 3 Polymerization / post-treatment / blending in the same manner as in Example 1 except that 3.4'-DABA was changed to 4.3'-diaminobenzanilide (4.3-3'-DABA). / Extrusion / Injection molding was performed to obtain a test piece, and the results of measuring the characteristics before and after the heat treatment are summarized in Table 3. The molded product of Comparative Example 3 was brittle as compared with the molded products of Examples 5 to 7, and only those having low bending strength could be obtained.

The polymer of Example 5 had the following theoretical structural formula, and the elemental analysis results showed good agreement with the theoretical values as shown in Table 4.

A / B / C = 2.80 / 2.24 / 0.56 (molar ratio) = 100/80/20 (mol%) The results of elemental analysis of the polymers of Examples 6 and 7 also showed good agreement with the theoretical values.

Examples 8 to 10 and Comparative Example 4 Polymerization / post-treatment / blending in the same manner as in Example 1 except that 3,4′-DABA was changed to 3,3′-diaminobenzanilide (3 / 3′-DABA). / Extrusion / Injection molding was performed to obtain a test piece, and the result of measuring the characteristic after the heat treatment is the fifth.
It is summarized in the table. The molded product of Comparative Example 4 was brittle as compared with Examples 8 to 10, and only a product having a low bending strength could be obtained.

The polymer of Example 8 had the following theoretical structural formula, and the elemental analysis results showed good agreement with the theoretical values as shown in Table 6.

A / B / C = 2.80 / 1.96 / 0.84 (molar ratio) = 100/70/30 (mol%) The results of elemental analysis of the polymers of Examples 9 and 10 also showed good agreement with the theoretical values.

Example 11 40-8.8 g (1.4 mol) of 1,3-bis (p-aminophenoxy) benzene as an aromatic diamine mixture and (3.
Example 1 except that 318.2 g (1.4 mol) of 4'-DABA was used.
When the polymerization operation and the post-treatment operation were performed in the same manner as
A polymer powder having ηinh = 0.66 and Tg = 280 ° C. was obtained.

This polymer had the following theoretical structural formula, and the elemental analysis results showed good agreement with the theoretical values.

A / B / C = 2.80 / 1.40 / 1.40 (molar ratio) = 100/50/50 (mol%) Next, 3% by weight of titanium oxide was added to the polymer powder obtained, and then Brabender Plastograph Ext. It was supplied to a ruder (processing temperature 300 to 360 ° C.) to obtain a melt extruded pellet.

Next, the pellets obtained are compression-molded (processing temperature: 330-360).
℃, pressure 50 ~ 100kg / cm ² ) to create an entrance test piece,
The molded test piece was placed in a hot air dryer and dried at 150 ° C for one day, then 220 ° C for 10 hours, 245 ° C for 14 hours, and then 260 ° C for 48 hours.
Heat treatment was performed for an hour. Subsequently, physical properties were measured, and the following results were obtained. FS = 1,800kg / cm ² , FM = 4
0,000kg / cm ² , HDT = 279 ℃.

Example 12 572.3 g (1.96 mol) of 1,4-bis (p-aminophenoxy) benzene and 3,4 as an aromatic diamine mixture
The procedure of Example 11 was repeated except that 190.0 g (0.84 mol) of 3'-DABA was used to obtain a polymer having the following properties.

ηinh = 0.72 Tg = 281 ℃ FS = 1,700kg / cm ² FM = 38,000kg / cm ² HDT = 280 ℃ In addition, this polymer has the following theoretical structural formula, and the elemental analysis results show good agreement with the theoretical values. It was

A / B / C = 2.80 / 1.96 / 0.84 (molar ratio) = 100/70/30 (mol%) <Effect of the invention> PAI of the present invention has good thermal stability in the temperature range of 300 to 400 ° C and It has good melt moldability due to its fluidity, and the physical properties of the molded product are excellent.By extrusion molding and injection molding, high-performance materials and molded articles can be produced with high molding productivity. Can be produced. And these materials and molded articles make use of excellent heat resistance and mechanical properties to make electrical and electronic parts,
Widely used in the fields of aerospace parts, automobile parts, office equipment parts, etc.

Claims (1)

[Claims] 1. And the ratio of each structural unit is B + C with respect to A1 mol.
Is 1 mol and B / C is in the range of 10 to 95 mol% / 90 to 5 mol%, and the logarithmic viscosity measured at 30 ° C. in an N-methyl-2-pyrrolidone solvent is 0.5 wt%. A thermoplastic aromatic polyamideimide copolymer characterized by having a content of 0.20 to 0.92. (However, X in the above formula is R represents an alkyl group or a halogen group having 1 to 4 carbon atoms, and a represents 0, 1 or 2, b or an integer of 1 to 4. )