JPH0125331B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing thermoplastic polyamide-imide resin molded articles having excellent heat resistance and mechanical properties. The present inventors have obtained an aromatic polyamide-imide that has good melt moldability by combining good thermal stability and fluidity in the temperature range of 300 to 400°C, and has an excellent balance of physical properties in a molded product. As a result of studies conducted for this purpose, it was discovered that the following thermoplastic aromatic polyamide-imide copolymer, which is a combination of four specific constituent elements, has the above-mentioned properties. A type

Structural unit of [formula] rank, B type

Structure of [formula] Building unit, C type

The structural unit of [formula] and D type

It consists of a structural unit of [Formula], the ratio of each structural unit is 1 mol of (C + D) to 1 mol of (A + B), and A/B is 4 to 70 mol%/96 to 30 mol%, C/D is 10-96
Thermoplastic polyamide-imide copolymer having a mole%/90 to 4 mole%. (However, Z in the above formula is a trifunctional aromatic group in which two of the three functional groups are bonded to adjacent carbon atoms, R is hydrogen or a methyl group, and X is a -SO ₂ - group. , -S- group or -O
- indicates a group. ) However, the heat resistance and mechanical properties of molded products made from the above-mentioned polyamide-imide copolymer are still not fully satisfactory.As a result of intensive studies aimed at improving this point, we decided to heat-treat the molded products under specific conditions. It has been found that the above objective can be effectively achieved by doing so. That is, the present invention provides a heat-resistant resin molded article, which is characterized in that a molded article obtained by melt-molding the above-mentioned polyamide-imide copolymer is heat-treated for 5 hours or more within a temperature range of 200°C or higher and below the glass transition temperature of the above-mentioned copolymer. The present invention provides a method for manufacturing. The thermoplastic polyamide-imide copolymer of the present invention is mainly composed of four units represented by A, B, C and D above. Here, the acid component (A+B) and the diamine component (C+D) are in a substantially equimolar ratio, and the ratio of each structural unit is A/B of 4 to 70 mol%/96 to 30 mol%, preferably 20 ~60 mol%/80~40 mol%,
C/D is selected from the range of 10 to 96 mol%/90 to 4 mol%, preferably 30 to 90 mol%/70 to 10 mol%. If the amount of A units is less than 4 mol % or more than 70 mol % of the (A+B) units, the melt viscosity of the resulting polyamide-imide copolymer becomes too high, which is inappropriate. On the other hand, if the amount of C units exceeds 96 mol% of the (C+D) units, the melt viscosity of the resulting polyamide-imide copolymer will become too high, which is inappropriate. Also, the C unit is in the (C+D) unit.
When the amount is less than 10 mol%, the D unit

In the case of [Formula], essentially only a polyamide-imide copolymer with a low degree of polymerization is obtained, and the D unit is

【formula】 or

In the case of [Formula], the flow start temperature and thermal decomposition temperature of the obtained polyamide-imide copolymer are too close to each other, making it unsuitable as a melt molding material. In addition, Z in the above A unit is a trifunctional aromatic group in which two of the three functional groups are bonded to adjacent carbons, for example,

【formula】

【formula】

【formula】

【formula】

Examples include [Formula]. Also, the A' unit when the imide bond in the A unit above remains in the state of an amic acid bond as its ring-closing precursor.

It is also within the scope of the present invention if [Formula] is present as a part of the A units (for example, 50 mol% or less, preferably 30 mol% or less). The polyamide-imide copolymer of the present invention can be produced using any of the many general production methods that have been proposed to date, but the following two are representative examples with high practicality. Here are some methods. (1) Isocyanate method: A method in which a mixture of an aromatic tricarboxylic acid anhydride and an aromatic dicarboxylic acid is reacted with an aromatic diisocyanate (for example, Japanese Patent Publication No. 51-6770). (2) Acid chloride method: A method in which a mixture of aromatic tricarboxylic acid anhydride chloride and aromatic dicarboxylic acid dichloride is reacted with an aromatic diamine (for example, Japanese Patent Publication No. 16908/1983, Japanese Patent Publication No. 49/1986)
12594, etc.). Among the above two methods, the acid chloride method has the advantage that raw materials are relatively easy to procure, and that it is easy to obtain a highly polymerized polyamide-imide with excellent linearity (less branched structure) through low-temperature solution polymerization. This is the most recommended manufacturing method.
Here, the acid chloride method will be explained in more detail as follows. That is, 1 mol of aromatic tricarboxylic anhydride monochloride/isophthalic acid dichloride (4-70/96-30 molar ratio) mixture and aromatic diamine ()

[Formula] 10-96 mol% Aromatic diamine ()

[Formula] (X represents -SO ₂ - group, -S- group or -O- group) Mixed diamine consisting of 90-4 mol% 0.9-
1.1 mol and dissolved in an organic polar solvent, −20 to 80
After mixing for about 0.5 to 1 hour at a temperature of ℃, add about 2 to 4 moles of hydrogen chloride scavenger to accelerate the polymerization reaction rate, and the polymerization reaction will be completed at room temperature in a reaction time of 0.5 to 10 hours. do. The polymer produced at this stage contains most of the A units (for example, 50 to 100%) of the polyamide-imide copolymer of the present invention.
ring-closing precursor amide amic acid unit

The structure converted to [Formula] is what is called a polyamide/amino acid. It is also possible to stagger the addition timings of aromatic tricarboxylic anhydride chloride and isophthalic acid chloride, in which case the resulting polymer will be a block copolymer. The organic polar solvent used in this first step includes N,N-dialkylcarboxylic acid amides such as dimethylacetamide and dimethylformamide, and heterocyclic compounds such as N-methylpyrrolidone and tetrahydrothiophene-1,1-dioxide. , cresol, xylenol, and other phenols, and N-methylpyrrolidone and N,N-dimethylacetamide are particularly preferred. Further, the hydrogen chloride scavenger added in the first step is trimethylamine, triethylamine,
Aliphatic tertiary amines such as tripropylamine and tributylamine, cyclic organic bases such as pyridine, lutidine, collidine, and quinoline, alkali metal hydroxides, alkali metal carbonates, alkali metal acetates, and alkaline earth metals. These include inorganic bases such as oxides, alkaline earth metal hydroxides, alkaline earth metal carbonates, and alkaline earth metal acetates, and organic oxide compounds such as ethylene oxide, propylene oxide, and the like. The polyamideamic acid obtained in the first step is then subjected to a second dehydration ring closure step and converted into the polyamideimide copolymer of the present invention. The dehydration ring closure operation is carried out either by liquid phase ring closure in solution or solid phase thermal ring closure by heating in 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 uses aliphatic anhydrides such as acetic anhydride and propionic anhydride, halogen compounds such as POCl ₃ , SOCl ₂ , molecular sieves, silica gel, P ₂ O ₅ ,
Using a chemical dehydrating agent such as Al ₂ O ₃ at a temperature of 0~
It is carried out at 120°C (preferably 10-60°C). The liquid phase thermal ring closure method is carried out by heating the polyamide/amic acid solution to 50 to 400°C (preferably 100 to 250°C). In this case, azeotropic solvents such as benzene, toluene,
It is more effective when xylene, chlorobenzene, etc. are used in combination. Solid phase thermal ring closure is performed by first isolating a polyamide/amic acid polymer from the polyamide/amic acid solution obtained in the first step and heat-treating it in a solid state. As a precipitant for isolating the polyamide/amic acid polymer, a liquid such as water, methanol, etc., which is miscible with the reaction mixture solvent but in which the polyamide/amic acid itself is insoluble, is employed. The heat treatment is usually selected from conditions of 150 to 350°C and 0.5 to 50 hours to ensure the desired ring closure rate and melt fluidity. If the treatment is carried out in the 250 to 350°C range for too long, the polymer itself tends to form a three-dimensional crosslinked structure, which significantly reduces the fluidity during melting, so care must be taken. Although the polyamide-imide copolymer targeted by the present invention can be obtained by the production method detailed above, other components other than those constituting the A unit, B unit, C unit, and D unit may be added to the reaction system. It is possible to copolymerize by using them together within a quantitative range that does not significantly reduce the melt processability and physical properties of the polyamide-imide that produces the copolymerization component, and is included within the scope of the present invention. The aromatic polyamide-imide copolymer of the present invention has a structure in which the imide units are partially ring-opened amic acid bonds, but most have a ring-closed structure, and in N-methylpyrrolidone solvent,
It is a high polymerization degree polymer with a logarithmic viscosity (ηinh) value of 0.20 or more, preferably 0.25 or more, measured at a polymer concentration of 0.5% by weight and 30°C, and can be used for various purposes as described below. Compression molding is usually carried out after dry blending the polyamide-imide copolymer powder of the present invention with different polymers, additives, fillers, reinforcing agents, etc. as necessary.
It is carried out under conditions of 300 to 400°C and a pressure of 50 to 500 Kg/ ^cm2 . In addition, extrusion molding and injection molding are performed by dry blending the polyamide-imide copolymer of the present invention with different polymers, additives, fillers, reinforcing agents, etc. as necessary, or by extruding the same into pellets. is fed into an extrusion molding machine or an injection molding machine and carried out under a temperature condition of 300-400°C. In particular, the aromatic polyamide-imide copolymer of the present invention has an excellent balance of thermal stability and fluidity in the 300 to 400°C region, and is useful for extrusion molding and injection molding. By further subjecting the polyamide-imide copolymer of the present invention to a heat treatment under high-temperature conditions, a molded product with improved physical properties such as heat distortion temperature, tensile strength, bending strength, and friction and wear properties can be obtained. Obtainable. Such heat treatment conditions include heating the molded product at a temperature of 200°C or higher and below the glass transition temperature of the molded product, particularly 220°C or higher and below (glass transition temperature -5°C) of the molded product for 5 hours or more, especially 10 hours or more. It is appropriate to heat it. When the heat treatment temperature exceeds the glass transition temperature of the molded article, the molded article is undesirably deformed during the heat treatment and has a strong tendency to impair its practicality. Although there are no particular restrictions on the equipment for performing this heat treatment, an ordinary electrically heated oven can suffice to achieve the purpose. For film and fiber manufacturing applications, the polymerization-finished solution can be applied in a dry or wet-dry casting process, or the isolated polymer can be melt-molded with appropriate additives as required. . Laminated boards are made by impregnating cloth or mat made of glass fiber, carbon fiber, asbestos fiber, etc. with a polymer solution, and then precuring it by drying/heating to obtain a prepreg.
It is manufactured by pressing under conditions of 50-300 kg/cm ² at ℃. For paint applications, after adding and mixing different types of solvents to the polymerization-completed solution as needed, the concentration can be adjusted and the solution can be put to practical use as it is. Hereinafter, the present invention will be further explained in detail using Examples and Comparative Examples. Note that the value of the logarithmic viscosity, which is a guideline for the molecular weight of the polymer, was measured in N-methyl-2-pyrrolidone solvent at a polymerization degree concentration of 0.5% and a temperature of 30°C. The melt viscosity of the polymer was determined by using a "Koka-type Flow Tester" manufactured by Shimadzu Corporation. After placing a sample that had been dried to an absolutely dry state in advance in a cylinder heated to 360°C and retaining it for 8 minutes, the melt viscosity of the polymer was 50 kg. The measurement was performed by extruding from a nozzle (diameter 0.5 mm, length 1 mm) at the center of the die while applying a load of . In addition, the gala transition temperature is
Measurement was performed using a PerkinElmer Model 1B DSC device. Note that measurements of various physical properties were performed according to the following methods. Bending strength (FS)...ASTM D790 Heat distortion temperature (HDT)...ASTM D648-56
(18.56Kg/cm ² ) Examples 1 to 4 and Comparative Examples 1 to 2 Metaphenylenediamine (MPDA) and 4 ,Four'-
After charging diaminodiphenyl ether (DDE) with the composition shown in Table 1, 3000 g of anhydrous N,N-dimethylacetamide was added and stirred to obtain a homogeneous solution. This mixture was mixed with dry ice/acetone solution.
Cool to 10°C and add 101.1 g (0.48 mol) of 4-(chloroformyl)phthalic anhydride (TMAC) and 146.2 g (0.72 mol) of isophthalic acid dichloride (IPC).
was added in small portions at such a rate that the temperature of the polymerization system was maintained at -10 to -5°C. After continuing stirring at 0°C for an additional hour, 214 g (2.1 moles) of anhydrous triethylamine was added in portions at a rate sufficient to maintain the temperature of the polymerization system below about 5°C. Next, after stirring as it was for 2 hours, 150 ml of pyridine and 300 ml (about 3.2 mol) of acetic anhydride were added, and the mixture was stirred overnight at room temperature. Next, the polymerization finished liquid was gradually poured into water under high speed stirring to precipitate the polymer into powder, which was thoroughly washed/dehydrated, and then heated in a hot air dryer at 150°C for 5 hours, followed by 200°C. After drying at ℃ for 3 hours, a polymer powder having logarithmic viscosity (ηinh), melt viscosity (μa), and glass transition temperature (Tg) as shown in the column of properties at the end of polymerization in Table 1 was obtained. . As can be seen from comparison with Comparative Example 1, the melt viscosity of Examples 1 to 4 was significantly reduced by the copolymerization of 4,4'-diaminodiphenyl ether. The theoretical structural formula and molecular formula of the copolymer obtained in Example 2 are as follows, and the elemental analysis results of the copolymer are shown in Table 2, showing good agreement with the theoretical values. .

【formula】

【formula】

【formula】

[Formula] - (C ₉ H ₄ N ₂ O ₃ -) _l / - (C ₈ H ₆ N ₂ O ₂ -) _n / - (C ₆ H ₄ -
)
_o / - (C ₁₂ H ₈ O) _p l/m/n/o = 0.48/0.72/0.96/0.24 (molar ratio) = 40/60/80/20 (molar ratio) In addition, Examples 1, 3 and Elemental analysis of the polymer No. 4 also showed good agreement with the theoretical values. Next, 2% by weight of tetrafluoroethylene resin (Aphron Polymist F-5, manufactured by Asahi Glass Co., Ltd.) as a sun protection agent was added to the obtained copolymer powder, and then
The pellets were fed to a Brabender Plastograph extruder (processing temperature 340-360°C) to obtain melt-extruded pellets. Next, the obtained pellets were compression-molded (processing temperature 330-360℃, pressure 50-100Kg/cm ² ) to create a test piece, and the molded test piece was placed in a hot air dryer and dried at 150℃ overnight. ℃ for 24 hours,
Heat treatment was performed at 245°C for 24 hours, followed by 24 hours at 260°C. Subsequently, physical properties were measured, and the results shown in the column of properties of molded product after heat treatment in Table 1 were obtained. Table 1 also shows the FS measurement results of the test pieces before heat treatment. However, the polymer obtained in Comparative Example 2 did not melt at 360°C, and a sufficiently molten molded article could not be obtained under the above compression molding conditions.

【table】

[Table] Example 5 TMAC75.8g (0.36 mol) and as acid components
IPC170.5g (0.84mol) as diamine component
103.8 g (0.96 mol) of MPDA and 59.6 g (0.24 mol) of 4,4'-diaminodiphenylsulfone (DDS), 121.8 g of propylene oxide as a deoxidizing agent.
A polymer powder having ηinh=0.32, μa=20×10 ³ poise, and Tg=265° C. was obtained by carrying out all the same operations as in the first half of Example 1 except for using (2.1 mol). This polymer has the following theoretical structural formula, and the results of elemental analysis also showed good agreement with this theoretical value.

【formula】

【formula】

【formula】

[Formula] l/m/n/o = 0.36/0.84/0.96/0.24 (mole ratio) = 30/70/80/20 (mole ratio) Next, using the obtained polymer, the second half of Example 1 In the same manner, 2% by weight of tetrafluoroethylene resin and 30% by weight of short glass fibers were blended and compression molded to obtain a molded test piece with FS=1.350Kg/cm ² . Subsequently, heat treatment was performed under the same conditions as in Example 1, resulting in Tg = 299°C, HDT = 285°C, FS = 2100Kg/
A molded article with excellent physical properties of cm ² was obtained. Comparative Example 3 Polymerization was carried out in the same manner as in Example 5 except that 297.9 g (1.2 mol) of 4,4'-diaminodiphenylsulfone was used alone as the diamine component, and the obtained polymer had ηinh=0.18 The degree of polymerization was unsatisfactory. Example 6 126.3g (0.6mol) of TMAC as acid component and
IPC121.8g (0.6mol), as diamine component
Everything is the same as the first half of Example 1, except that 51.9 g (0.48 mol) of MPDA, 155.7 g (0.72 mol) of 4,4'-diaminodiphenyl sulfide, and 192 g (1.9 mol) of N-methylmorpholine are used as deoxidizing agent. After performing the operation, ηinh=0.48, μa=3×10 ³ poise,
A polymer powder with Tg=250°C was obtained. This polymer has the following theoretical structural formula, and the results of elemental analysis also showed good agreement with this theoretical value.

【formula】

【formula】

【formula】

[Formula] l/m/n/o = 0.6/0.6/0.48/0.72 (mole ratio) = 50/50/40/60 (mole ratio) Next, using the obtained polymer, the second half of Example 1 In the same manner, 2% by weight of tetrafluoroethylene resin was blended and compression molded to obtain a molded test piece with FS = 560 Kg/cm ² . Subsequently, heat treatment was performed under the same conditions as in Example 1, resulting in Tg = 282°C and HDT = 270.
A molded article having excellent physical properties of ℃ and FS=850 Kg/cm ² was obtained. Comparative Example 4 Polymerization was carried out in the same manner as in Example 6 except that 259.4 g (1.2 mol) of 4,4'-diaminodiphenyl sulfide was used alone as the diamine component. The μa was 100×10 ³ poise or more, indicating extremely poor melt fluidity.

Claims (1)

[Claims] 1 Consists of a structural unit of formula A [formula], a structural unit of formula B [formula], a structural unit of formula C [formula], and a structural unit of formula D [formula], and the proportion of each structural unit is is 1 mol of (C+D) per 1 mol of (A+B), and A/B is 4 to 4
A thermoplastic polyamide-imide copolymer having a C/D of 70 mol%/96 to 30 mol% and a C/D of 10 to 96 mol%/90 to 4 mol% (however, Z in the above formula is 2 of the 3 functional groups). A trifunctional aromatic group in which the functional group is bonded to adjacent carbon atoms, R is hydrogen or methyl group, and X is -SO ₂ - group, -S- group or -O- group). A method for producing a heat-resistant resin molded article, which comprises heat-treating the molded article at a temperature of 200° C. or higher and lower than the glass transition temperature of the copolymer for 5 hours or longer.