JPS5933100B2 - Manufacturing method for aromatic copolyamide molded products - Google Patents

Description

Detailed Description of the Invention The present invention provides a high-strength, high Young's modulus, aromatic copolyamide that is useful as a rubber reinforcing material for tires, hoses, belts, etc., strong ropes, strong tapes, strong films, and furthermore, as a reinforcing material for plastics. The present invention relates to a method for producing molded products, and aims to improve fifurl resistance, which is a drawback of aromatic copolyamide molded products.

It is known that aromatic polyamides (PPTA-based polymers) with paraphenylene groups incorporated into the main chain, such as polyparaphenylene terephthalamide (PPTA), can easily be made into molded products with high strength and high Young's modulus. (For example, see Japanese Patent Publication No. 47-2489.) Practical tests have already been carried out as tire cords and plastic reinforcing materials, and some brands have been commercialized.

In addition to PPTA-based polymers, molded products with high strength and high Young's modulus can also be obtained from polyamides containing mainly para-skeleton or hard rings with parallel axis bonds, and aromatic polyamides containing rigid heterocycles with good linearity. Known.

[For example, BlackW. PrestOnJ●；2High
h-MOduluswhOllyOrOmaticfi
bers/', Marcel Dekker, Inc. (
(1973)] Hereinafter, PPTA-based polymers and these polymers will be collectively referred to as rigid parallel axis-bonded polyamide polyheterocycles. These rigid parallel axis bonded polyamides
Polyheterocycles dissolve at high concentrations in certain solvents, especially some mineral acids such as concentrated sulfuric acid and chlorosulfuric acid, and provide anisotropic solutions.

This phenomenon helps to make the structure denser and more highly oriented during solidification. For example, when an anisotropic solution of PPTA dissolved in 100% sulfuric acid at 80°C or higher to 20wt% is mixed with an air layer of about 0.5 to 1 degree, High strength and high Young's modulus fibers can be obtained without additional hot drawing or heat treatment by the method of flow tension spinning in an aqueous coagulation bath flowing through an extrusion funnel (see Japanese Patent Application Laid-Open No. 47-39458). However, the rigid parallel-axis bonded polyamide polyheterocycle fibers or films obtained in this manner have a serious drawback in that they are extremely susceptible to fifrillation due to bending or abrasion.

Moreover, these fibers or films not only do not have their fibril resistance improved by relaxation or tension heat treatment, but also tend to have a tendency to deteriorate in fifrill resistance due to the progress of crystallization, decrease in elongation, and the like. Some of the present inventors have solved various difficulties and problems in the polymerization, spinning and solvent recovery steps while retaining the properties of high strength and high Young's modulus of the above-mentioned rigid and parallel axis bonded polyamide polyheterocycles. One way to solve this problem is to copolymerize monomers with a certain type of semi-flexible, non-parallel axis bond, which allows normal dry, wet, or semi-dry/semi-wet molding from the polymerization solution. It has been discovered that a molded product with high strength and high Yanog ratio can be obtained by applying stretching at a satisfactory high temperature and high magnification.

(Japanese Unexamined Patent Publication No. 51-1136916, Japanese Patent Application No. 1983-10
No. 6812) However, although some improvement in fifurl resistance was observed, it was not sufficient. The present inventors have conducted intensive research to improve the fifurl resistance of these aromatic copolyamide molded products. As a result, aromatic copolyamide molded products having a degree of crystallinity and a degree of crystal orientation that satisfy certain specific conditions have the following properties: We have discovered that fibril resistance can be greatly improved by heat treatment that satisfies certain specific conditions without reducing strength or Young's modulus, and have arrived at the present invention.

That is, the present invention is directed to (1) a group represented by the general formula -<○>-x-k:)- (wherein -x- is selected from -C-), in which 85 to 60 mol% is a group in which the bonding chain is It consists of an aromatic carbocyclic residue, an aromatic heterocyclic residue, and/or a combination thereof, both of which extend in coaxial or parallel axes directions.

R is a hydrogen atom and/or an alkyl group having 2 or less carbon atoms. ] A molded product having a degree of crystal orientation determined by X-ray diffraction of 89% or more as determined by X-ray diffraction of a repeating unit represented by the following formula [where Tmq indicates the pseudo-melting point of the aromatic copolyamide.

] This is a method for producing an aromatic copolyamide molded article that is difficult to form into fifuryls, and is characterized by heat treatment at a temperature T(1) that satisfies the following.

In the method of the present invention, R in the general formula is a hydrogen atom, a methyl group,
A larger ratio of alkyl groups to hydrogen atoms, selected from ethyl groups, has the advantage of increasing solution stability and allowing spinning from more concentrated polymer solutions, but it also reduces the crystallinity of the polymer and A disadvantage arises in that the range of suitable stretching conditions becomes narrower.

From this point of view, the ratio (molar ratio) of alkyl groups to hydrogen atoms is preferably 1/1 to ζ1/3. Particularly when the highest performance is required, it is preferred that all R's are hydrogen atoms. In the formula, -X- is -
0-, -S-, -SO2-CH2-, -C-, but the bendability of this residue seems to contribute to hot stretchability, and -O- or -S-, X to Vf
It is most preferable that all of A in the general formula are -0-.
85 to 60 mol % of r is selected from aromatic carbocyclic residues, aromatic heterocyclic residues in which bond chains extend coaxially or in parallel axes, and combinations thereof.

For example, the following are preferably used. The method of the invention is also applicable to aromatic heterocyclic residues which are not completely coaxial, but which are bonded by ring atoms which exhibit the greatest spacing, e.g.

However, from the viewpoint of ease of polymerization and cost of raw materials, a polymer in which 85 to 60 mol % of Ar in the general formula is all paraphenylene groups is most preferably used.

Specifically, the aromatic copolyamide molded article according to the method of the present invention is obtained as follows.

(1) Preparation of polymer solution Although various known methods can be employed as the polymerization method, for example, a method in which diamine and diacid chloride are solution-polymerized in an aprotic organic polar solvent is preferably used.

For example, paraphenylenediamine [H2N→○HNH2
], 3,4'-diaminodiphenyl ether and terephthalic acid dichloride in a predetermined number of moles (A mole, B mole, and C mole, respectively)
is weighed, polymerized in N-methyl-2-pyrrolidone, and then the hydrochloric acid generated by the reaction is neutralized with a neutralizing agent (for example, CaO, CaOH, etc.) to obtain a polymer solution.

This solution can be used as it is as a spinning stock solution by appropriately adjusting the concentration of the polymer and the degree of polymerization. Here, the mole fraction [-XIOO%] of the component having a skeleton, in this case 3,4L diaminophenyl ether, is Δ-! - When P↓ρ is less than 15 mol%, the polymer behaves similar to polyparaphenylene terephthalamide and cannot be stably dissolved in organic solvents, and the fibril resistance of the molded product is reduced by the heat treatment of the present invention. It doesn't improve no matter how much you try.

If the amount exceeds 40 mol %, not only will rigidity be lost, making it difficult to obtain a molded product with desirable mechanical properties, but also the mechanical properties will be significantly reduced by heat treatment. (2) Spinning and stretching The spinning stock solution obtained in this way is desolvated by conventional methods such as wet molding, dry molding, semi-dry and semi-wet molding, etc., and is further heat-stretched to obtain predetermined physical property values. A molded article is obtained.

For example, when the polymer solution is an amide solvent, a metal halide salt aqueous solution is preferable as the coagulation bath for wet molding, and depending on the composition of the polymer, a coagulation bath containing an amide solvent and an aqueous system is preferable for coagulation molding with less devitrification. give something. The molded product obtained in this way is washed thoroughly with water, dried, and then stretched at a draw ratio higher than the pseudo-melting point (Tmq) of the polymer and at a draw ratio of generally 7 times or more. This results in a molded product with high strength and high Young's modulus, with a degree of orientation of 89% or more.

(3) Heat treatment The molded product obtained in this way has good properties (compared to a molded product obtained from a rigid-parallel-axis-bonded polyamide/polyheterocyclic polymer, which has the same strength and initial Young's modulus). However, it has the disadvantage of poor fifurl resistance.

This drawback can be greatly improved by heat treatment as described below without impairing physical properties such as strength and initial Young's modulus. That is, the molded article is subjected to a constant length or tension treatment at a temperature T(4) that satisfies the relationship Tmq-15≦T≦Tmq with respect to the pseudo-melting point Tmq obtained by the measuring method described below. Any treatment method may be used, but in the case of fibers, for example, in order to prevent fusion between single filaments, it is better to guide the fibers through a heated hollow pipe from a feed roller than to use a contact heating method such as a hot plate. A non-contact and continuous method, such as subsequent winding through a take-up roller, is preferably used.
At this time, an inert gas (for example, nitrogen gas) may be flowed into the hollow pipe in order to prevent coloring of the molded product or a slight decrease in strength. The heat treatment time is sufficient as long as the temperature of the molded product reaches a predetermined temperature, and a particularly long treatment time is not required, but a time of about 0.1 seconds to 60 minutes is desirable for process control. When the heat treatment temperature is below (Tmq-15)℃, the effect of heat treatment is not sufficient, and (Tmq+
At temperatures above 30)°C, there is an effect of improving fifurl resistance, but
A significant decrease in strength or initial Young's modulus is undesirable.

The molded product to be subjected to heat treatment must have a degree of crystal orientation determined by X-ray diffraction of 89% or more, and preferably has a degree of crystallinity of 75% or more.

If the degree of crystal orientation of the molded product is less than 89%, the heat treatment causes a decrease in strength or initial Young's modulus, which is thought to be due to relaxation of orientation, making it impossible to achieve the intended purpose. Regarding the heat-treated molded product obtained in this way, in the case of fiber, 0
．． In the case of 19/Del film, the degree of improvement in fibril resistance was clearly determined by observing the state of the sample after sliding it against a stainless steel edge at right angles 50 times under a tension of 10 kg/Md. be understood.

Next, methods for measuring each parameter shown in the text and examples will be described.

Note that 2 machine direction 2 means the stretching axis direction of the molded product, and unless otherwise specified, it is the stretching direction of uniaxial stretching. Method for measuring the degree of orientation in the machine direction: X-ray generator manufactured by Rigaku Denki Co., Ltd.
O32A2), a wide-angle diffractometer and a counting circuit unit are used, and a fiber rotating sample stage that can perform measurements in the azimuthal direction is attached as the sample stage.

The sample was heated at 4.5C to have a width density of approximately 2.29/Cm.
Attach to TL length holder. An oriented diffraction intensity curve is obtained by rotating the fiber in the azimuthal direction while maintaining the 20 value with the maximum peak on the equator. It is easy to find the baseline, and from the midpoint of the perpendicular line drawn from the peak to this baseline, draw a straight line parallel to the baseline and find the point of intersection with the shoulder of the peak. Assuming that the length (half width at half maximum) of the line segment formed by this intersection is H (degrees), the degree of orientation f is determined by the following equation.
1Q81U ('~b) This method is introduced in general books on polymer X-ray diffraction.

The detailed measurement conditions are as follows.

The crystallinity analyzer uses the above-mentioned X-ray generator, wide-angle diffractometer, counting circuit, and fiber rotating sample stage, and the sample width density is also the same.

While rotating the sample in a vertical plane, sweep the diffractometer in the radial direction to obtain a total diffraction curve when the fibers are randomly oriented. Next, the diffraction charts in the meridian direction are superimposed to determine the reflections caused by the amorphous portion. By excluding the peak due to the crystal part in the meridian direction, a clean base curve due to the reflection of the amorphous part can be obtained. Furthermore, the scattering curve due to air is determined. The crystallinity Xcr is calculated by determining the following C, T, and A in the range of 10 et al. <20 <400.

C = Area surrounded by (total diffraction curve) and (base curve due to reflection of amorphous part) T - Area surrounded by (total diffraction curve) and (zero height line) A = (air scattering curve) and (height The area surrounded by the zero line) However, K is a correction coefficient depending on the type of polymer,
In the group of polymers of the present invention, K=12.

The conditions for measuring this value are as follows. After washing off the solvent, the water-containing polymer was dried at 100°C under vacuum for 3 hours,
Dissolve in 97.5% sulfuric acid at a concentration of 0.59/dl.

Measure the flow time (TO) of only concentrated sulfuric acid in a constant Ostwald type viscosity tube, then measure the flow time (t) of the 0.59/D2 solution, and calculate 1. V. Calculate. however,
In this case C=0.5f! /dl.

Pseudo-melting point Tmq It is not certain whether the polymer group used in the present invention has a true Tm.

Since these polymer groups are copolymers, they naturally exhibit a wide melting point range, and it is considered that accurate Tm cannot be determined. However, the melting start temperature of these polymer groups can be observed using a flow tester or DTA. Here, the melting start temperature (temperature at the intersection of the baseline and the slope of the endothermic peak) detected at a heating rate of 10°C/min for DTA in a nitrogen stream is Tmq
(pseudo-melting point). Tmq is 100kg/
The polymer flows out from a nozzle having a diameter of 1 nm or more and a flow path of 101 or less under an extrusion pressure of 100 nm or more. However, at the same time, crosslinking progresses and the outflow is interrupted. Determination of Tmq is reliably performed by using a combination of DTA and a flow tester. D.T.A.
The endothermic peak start temperature and the outflow start temperature of the flow tester almost match. Alternatively, by taking an X-ray diffraction diagram at high temperature, Tmq can be determined by observing the decrease in the crystal phase. Among the polymer groups used in the present invention, nearly random copolymers have Tmq between 400°C and 500°C.
was found to have the following. The effects of the present invention will be illustrated below with reference to Examples.

In the examples, De, S, E, and Y represent denier, strength (9/De), elongation %, and initial Young's modulus (9/De), respectively. Also, the proportion of Ar in the general formula of the polymer is
> -X- <K><The ratio of the skeleton is represented by mol %, and x -ferrous. Reference Example 1 This reference example describes the polymerization of a polymer (abbreviated as DDPE-X) obtained from the polymerization of paraphenylene diamine, 3,4/-diaminodiphenyl ether, and terephnotaric acid dichloride.

Moisture content 100PP01 in a 100m1 truncated conical flask
Pour the following 70 ml (7) of NMP, accurately weigh the specified weight of paraphenylene; diamine (1), 3,4/-diaminodiphenyl ether (2), and add NM under a nitrogen stream.
Dissolves in P.

The solution maintained at room temperature (approximately 2°C) was vigorously stirred (approximately 800 rpm) with a screw connected to a three-one motor.
), terephthalic acid dichloride (3) in a powder form finer than 30 mesh is added in an equimolar amount to the diamine. After stirring vigorously for about 1 hour, a viscous unneutralized dope is obtained. At this stage, add calcium oxide in an amount equivalent to 99.7% of the generated hydrogen chloride, add more calcium chloride if necessary, and stir for more than 3 hours.
Stable dopes were obtained except for DPE-7.5. A part of the obtained dope was coagulated with water while stirring in a blender, thoroughly washed and dried, cooled to liquid nitrogen temperature and pulverized, and the obtained fine powder was passed through a 30 mesh sieve and the Tmq was measured. Served. Tmq was determined by differential thermal analysis (D
TA), 10℃Ai? The temperature at which the endothermic peak of melting in nitrogen rises is also shown. T
9 immersed a glass string in the dope, dried the dope attached to the glass string at 150℃ for 30 minutes, immersed it in methanol at room temperature overnight, and dried it almost completely in a vacuum dryer (1300C) to remove the sample. After heat treatment at 300° C. for about 10 minutes and cooling slowly, the sample was observed using TBA. The rise of the peak of the dynamic principal dispersion was defined as Tl. (Temperature increase rate 3℃/min)
By performing the heat treatment at 300°C, it is possible to reduce the overlap of the secondary dispersion caused by the benzene ring with the main dispersion that occurs at around 100°C. The amount of each monomer charged when creating DDPE-X and the measured T', Tm
q is shown in Table 1. When X=50, Tmq Reference Example 2 DDPE-15, -20, -25, prepared in Reference Example 1
Wet spinning was carried out using a syringe type extruder using dopes of -35, -40 and -50.

The discharge conditions and coagulation conditions are shown in (Table 2). The coagulated and wound yarn was then heated at 70°C x 2m and 90°C at a speed of 3m/min.
It was placed in a water washing process of 5°C x 8m.

Furthermore, 1100CX2.5m1, then 240CX2.
The film was dried for 5 m using a roller, stretched at a temperature set based on T9 and Tm measured in Example 1 for each composition of DDPE, and stretched at a maximum stretching ratio of 0.8 times, and then wound up. Heating during drawing of the yarn was performed using a 50c1n stainless steel hot plate with a mirror finish, and the set temperature (surface temperature at 300m near the center) was approximately Tmq + 20°C.
It is. The maximum stretching ratio was determined by averaging five measurements. Note that the feeding speed for stretching was 3.0 m/min. (Table 4)
The yarn quality and drawing conditions of the drawn yarn are shown below. Crystal parameters (crystal orientation f and crystallinity Xcr) Example 1 The drawn yarn obtained in Reference Example 2 was made into
0 (XIL) by running it in a cylindrical electric furnace.

The heat treatment conditions and fiber quality of the heat treatment system are shown in the table below. 0.19 for the heat-treated and untreated systems thus obtained.
/De, the sample was set along the surface of a perpendicular stainless steel edge and in a direction perpendicular to the edge line, and was rubbed back and forth in this direction 50 times. The situation of occurrence was investigated.

The results are shown in the table below. The marks in the table indicate the following results.

◎: Almost no fifrills were observed.

○: Generation of fine fibrils is observed under a microscope. Δ: Generation of fine fibrils is observed with the naked eye.

×: Fuzzing of the fifrills occurred at the edges, and the threads were often broken. Example 2 7.02 NMP was charged into a 101 stainless steel reactor (moisture content 200 P), and paraphenylenediamine was charged at 8
7,69,3,4'-diaminodiphenyl ether
62.1f! After dissolving under a nitrogen stream, 330.09 g of terephthalic acid dichloride (fineness of 30 mesh or more) was quickly added and stirred vigorously.

After about 3 hours, 90.79 g of calcium oxide was added, and the neutralization reaction was completed over about 5 hours. The dope obtained is 100
It has a falling ball viscosity of 96 boads at 1. V. was found to have a 2.1 polymer. Next, this dope was extruded through a slit with a width of 1C7rL and a thickness of 0.5mm, and after coagulating, washing with water, and drying, it was rolled up and heated at 500°C (T
The stretched film, which was stretched by about 14 times using a hot plate having a surface temperature of 1.0 mq or more, was strong, and the values of F, Xcr, and D were within the claimed range.

When this film was examined for fibrillation in the same test as in Example 1 under a tension of 0.1 kg/MlL, it was found that fine fibrous substances separated from the surface due to the fibrillation of the film were attached to the edges of the stainless steel. .

The film was heat treated at 460°C for 30 seconds using the same equipment as in Example 1, and the same test as above was conducted.
Macroscopically, almost no fifurrylation was observed.
Examples 3 to 6 Polymer solutions were obtained by polymerizing in the same manner as in Reference Example 1 using the raw materials and charging ratios shown in the following table.

Claims (1)

[Claims] 1 General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [I] and/or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [II] [In the formula, 15 to 40 mol% of Ar is ▲ There are mathematical formulas, chemical formulas, tables, etc.▼ (However, -X- is -
It is a group selected from O-, -S-, -SO_2-, -CH_2- and ▲mathematical formula, chemical formula, table, etc. It is an aromatic carbocyclic residue and/or an aromatic heterocyclic residue extending in the parallel axis direction. R is a hydrogen atom and/or an alkyl group having 2 or less carbon atoms. ] A molded article having a crystal orientation degree of 89% or more determined by X-ray diffraction of an aromatic copolyamide consisting of repeating units represented by the following formula Tm^q-15≦T≦Tm^q+30 indicates the pseudomelting point of the aromatic copolyamide. ] A method for producing an aromatic copolyamide molded article, characterized by heat treatment at a temperature T (° C.) that satisfies the following. 2. The method for producing an aromatic copolyamide molded article according to claim 1, wherein all R's in the general formula [I] or [II] are hydrogen atoms. 3. The method for producing an aromatic copolyamide molded article according to claim 1 or 2, wherein all Xs in the general formula [I] or [II] are oxygen atoms. 4 85-6 of Ar in the general formula [I] or [II]
The method for producing an aromatic copolyamide molded article according to claim 1, 2, or 3, wherein all 0 mol% is paraphenylene groups. 5. The method for producing an aromatic copolyamide molded article according to any one of claims 1 to 4, wherein the tension during heat treatment is 50% or less of the breaking tension at the heat treatment temperature. 6. The method for producing an aromatic copolyamide molded article according to any one of claims 1 to 5, wherein the heat treatment is performed in an inert gas. 7. The method for producing an aromatic copolyamide molded article according to any one of claims 1 to 6, wherein the aromatic copolyamide molded article is a fiber.