JPH01287167A - Production of high polymer composite material - Google Patents

Abstract

PURPOSE:To obtain a high polymer composite material, by dipping a high polymer solution, containing a reinforcing high polymer consisting of a polyazole and a matrix polymer and assuming optical anisotropy in a coagulating solution, passing the solution through an apparently optically isotropic phase and coagulating the solution. CONSTITUTION:A high polymer solution (preferably >=30% solvent concentration), prepared by dissolving (A) a reinforcing high polymer consisting of a polyazole (e.g. poly-p-phenylene benzobisthiazole) having a rodlike skeleton and (B) a matrix polymer (e.g. aromatic polyamide) having fusibility within a range so as to provide 5-45% ratio [A/(A+B)] in a solvent (e.g. methanesulfonic acid) and assuming optical anisotropy is introduced into a coagulation bath (e.g. aqueous solution of methanesulfonic acid) and composition, temperature conditions, etc., of the coagulation bath and regulated so that the above-mentioned high polymer solution may be passed through an apparent optical isotropic phase and then coagulated after dipping in the coagulation bath. Thereby, a film is formed to afford the aimed composite material.

Description

DETAILED DESCRIPTION OF THE INVENTION Fiber-reinforced plastics have improved dramatically, and due to their physical properties, they have been regarded as important as load-bearing structural materials, and various materials have been developed and put into practical use. The production of such composite materials requires complicated step-by-step operations such as arranging separately manufactured reinforcing fibers in one direction and further impregnating a matrix, which also includes a step in an autoclave. Requires.

On the other hand, the strength and durability of composite materials are largely influenced by the state of the interface between the reinforcing fibers and the matrix polymer. Since the fibers themselves are macroscopic at the interface between the two, defects existing there propagate macroscopically and lead to destruction of the composite material.

In order to solve this drawback, instead of using fibrous reinforcing material that can only be dispersed in a macroscopic form, a high modulus reinforcing polymer and a matrix polymer are dissolved in a common solvent, and both can be dispersed in a microscopic form. We are considering manufacturing a polymer composite in which the reinforcing polymers are dispersed and mixed in an extremely microscopic state by mixing them in a molecular order, solidifying and molding them, and in which the reinforcing polymers are oriented. It has been.

The present inventors currently use polyazole-based polymers such as poly-p-phenylenebenzobisthiazole, which provide excellent tensile modulus, as reinforcing polymers as organic polymer fibers, and use various combinations of U-based polymers such as various matrix polymers. We have been studying the possibility of creating a high dicholus in the art, but there were drawbacks such as a low tensile modicolus compared to the additivity value expected when the molecular components of the art dealer are sufficiently oriented. In addition, in order to obtain a molded product in which polymer composite films are laminated, it is better to increase the thickness of the film, but in conventional wet molding, increasing the thickness causes coagulation. The condition deteriorated, and a good film could not be obtained.

In order to solve this problem, the present inventors used a polyazole polymer such as poly-p-phenylenebenzobisthiazole as a reinforcing polymer, and developed a system using a flexible polymer as a matrix polymer. The present invention was arrived at as a result of intensive studies on making the film more modular and thicker.

Purpose of the Invention As a result of intensive research in order to obtain a polymer composite with high performance mechanical and thermal properties, the present inventor has discovered that an optically anisotropic solution with an optical anisotropy that has an apparent 1 The present inventors have discovered that an excellent polymer composite can be obtained by substantially solidifying the polymer after passing through an optically isotropic solution.

That is, the present invention uses a polymer solution mainly containing a reinforcing polymer (A) consisting of polyazole having a substantially rod-like skeleton and a matrix polymer (B) that controls fusion properties.
In the method of manufacturing a polymer composite in which it is introduced into a coagulation bath and formed into a film, the polymer solution initially exhibits optical anisotropy, and after being immersed in the coagulation bath, the optical iP9 etc. shown above appear. This is a method for producing a polymer composite, which is characterized by substantially causing coagulation after passing through an isotropic phase.

The reinforcing polymer (A) used in the present invention has the following formula [wherein X represents -s-, -o- or -NH-, and the bonds (a] and (0) are further azole a bond forming a ring or a hydrocarbon ring, or a hydrogen atom is bonded to one of them and the other bond is 3-.] A substantially rod-shaped substance having an azole skeleton represented by Examples include backbone polyazoles, specifically those described in U.S. Pat.
There are polymers described in US Pat. No. 207,407,
Among them, polyazoles such as poly-p-phenylenebenzobisthiazole, poly-p-phenylenebenzokylysyl, and poly-p-phenylenebenzobisimidazole are mentioned.

The reinforcing polymer (the molecular weight of A> is 1 of the total molecular weight) has an intrinsic viscosity of 1 or more, preferably 1.5 or more, particularly preferably 2 or more.On the other hand, those whose intrinsic viscosity is too high is not preferable, and if it is 30, a good product cannot be obtained.In order to fully utilize the effects of the present invention, the intrinsic viscosity of the reinforcing polymer is preferably 25 or less, particularly preferably 20 or less.

71 helix polymer (B) used in the present invention
are dissolved in the same solvent as the reinforcing polymer (△); nylon 6, nylon 6G, nylon 610. Nylon 12. Aliphatic polyamides such as N1'11; aromatic polyamides such as polyhexamethylene isophthalamide; flexible aromatic polyamides into which flexible groups such as ether groups have been introduced; polyester: to polycarbonate 1; polyvinyl acetate; borisulf A; poly] di-terzalf4;
Examples include polyetherimide, poly]2-terkene, polyphenylene, and narnoide.

The common solvent may be one that dissolves the constituent polymers, and examples thereof include acidic solvents such as concentrated sulfuric acid, methanesulfonic acid, polysulfonic acid, polyphosphoric acid, triphyl acetic acid, and phosphoric acid. . These may be mixed and used as appropriate. In addition, to suppress the hydrolysis of dissolved polymers,
Additives may be introduced to minimize the amount of water in the solvent.

For example, addition of fuming sulfuric acid, chlorosulfonic acid, etc. may be mentioned.

The stock solution for forming a polymer composite is a polymer solution in which a reinforcing polymer and a 71-helix polymer are dissolved in the above-mentioned common solvent, and it is necessary that the polymer solution has optical anisotropy. After the polymer solution is immersed in a coagulation solution, it is necessary that the polymer solution is coagulated through an apparent optically isotropic phase.

That is, a predetermined polymer solution is prepared, spread thinly on a slide glass, and placed so that the thickness of the polymer solution is 0.5.
Adjust J5 with a slide so that it is mm. The sample thus prepared is placed under observation using a polarizing microscope with a cross-hole. If a polymer solution on a slide glass is placed on a sample stage and the field of view remains bright even when the sample stage is rotated, the polymer solution exhibits optical anisotropy.

The following measurement method was used to determine the phase state of the polymer solution after it was immersed in the coagulation bath.

Using a melting point measuring device (YANAG IMOTO■), apply a polymer solution to Prepara-1 to a thickness of 0.5 mm, and place it in a petri dish container with a diameter of approximately 17 mm. Place it on a silver heater stand and heat it with a heater until it reaches the same temperature as the coagulation bath. At this stage, a coagulating liquid that has been separately heated to the same temperature in advance is poured into the petri dish container.

After injecting the coagulation liquid, the polymer solution on the preparation takes various states depending on the conditions when observed under crossed Nicols conditions.

When we use a polymer solution that exhibits optical anisotropy and the field of view is bright, the above procedure results in: ■ Cases in which the field of view remains bright over time even after the coagulation liquid enters; ■ The apparent optical anisotropy There are two cases: (1) an isotropic state in which the visual field becomes dark; and (2) an apparent optically isotropic state in which the visual field darkens and then becomes bright again.

In the present invention, film forming conditions that temporarily cause optical isotropy to appear during the solidification process are cases that correspond to (1) and (2).

Optical anisotropy may be caused by polymers forming so-called liquid crystals, or may be caused by alignment of polymers. Optical anisotropy in the present invention refers to the former case. Anisotropy caused by orientation can be identified by rotating the sample stage, which produces periods of brightness and darkness in the field of view, whereas anisotropy derived from liquid crystals does not substantially change the brightness of the field of view when the sample stage is rotated. It can be determined by this.

An apparently optically isotropic state is when a given polymer solution is observed under a polarizing microscope. Initially, it exhibits a pattern between each ridge, but it gradually changes to a uniform color. The bullet holes of the light decrease and become darker, and this shows the state between the uniform color at this time and the time when the intensity of the light gradually decreases and becomes a constant darkness. When this state is observed with the naked eye, it appears to be transparent and optically isotropic. Therefore, this state will be called an apparently optically isotropic state.

A polymer solution starts coagulating through interdiffusion with a coagulating liquid, but if the coagulating liquid contains an appropriate amount of solvent that dissolves the polymer, the coagulating liquid will coagulate into the polymer solution system through interdiffusion. During the permeation and solidification transient state, the polymer concentration in the polymer solution decreases relatively, and as a result, it becomes possible to exhibit optical isotropy.

Furthermore, the appearance of apparent optical isotropy in this solidification process can be enhanced by utilizing the phenomenon of phase transition due to temperature of the polymer solution. That is, for example, by immersing an optically anisotropic solution extruded at room temperature into a coagulation bath at a higher temperature, the appearance can be transformed to optically isotropic solution.

The coagulation bath for coagulating the polymer solution is an important factor in the present invention.

The coagulating liquid is a system in which a non-dissolving solvent is mixed with the solvent used for the polymer solution, such as a sulfuric acid aqueous solution.

Examples include a methanesulfonic acid aqueous solution and a phosphoric acid aqueous solution.

In order to more easily achieve the effects of the present invention during the coagulation process, the concentration of the solvent used in the polymer solution should be reduced to 30%.
It is preferable to do the above. Further, it is preferable for thick films to have a coagulation bath temperature higher than the transition temperature of the polymer solution from optical anisotropy to isotropy. When the solvent concentration in the coagulation bath is low, the polymer solution immediately coagulates and remains anisotropic. Also, if the temperature of the coagulation bath is too high, the coagulation rate will increase and the material will solidify in an anisotropic state.

In order to maximize the effects of the present invention as described above, it is necessary to appropriate the composition and temperature conditions of the coagulation bath.

It is also preferable to use the coagulation bath in two or more stages, and in order to bring out the effects of the present invention more effectively, it is preferable to use at least two or more stages. In the first stage coagulation bath, the main purpose is to transform the optically anisotropic solution into an apparently optically isotropic solution, and in the second stage coagulation bath, substantial coagulation is promoted. It is.

In the film forming method, the polymer solution extruded from a T-die or the like may be directly immersed in a coagulation bath, or after being cast onto a drum, the drum may be immersed in the coagulation bath. After the solidified unstretched film has sufficiently removed the remaining solvent, it is necessary to neutralize it with ammonia or helium hydroxide, especially in the case of an acid solvent system.

If an optically anisotropic polymer solution is immersed in a coagulation bath and it solidifies without undergoing apparent isotropy, both component polymers will form during subsequent stretching. The degree of orientation of the material does not reach a sufficiently high value, and its mechanical property values are of low values. On the other hand, if the polymer passes through an apparent optically isotropic phase during the solidification process, the subsequent stretching will proceed smoothly, making it possible to obtain a polymer composite film with excellent mechanical properties.

The reason for this is not clear, but in the present invention (J), the reinforcing polymer is cast in an anisotropic solution and then transferred to the isotropic solution in the solidification process. 7
This is thought to be because the microdispersion into the 1 to Lynx polymers is dispersed in a form that facilitates performance development.

The dried film is then subjected to a conventional stretching operation used for stretching films and the like to form a high modulus film.

The ratio of the reinforcing polymer (A) and the 71~lix polymer (B) used in the present invention is A/A+B of 5~
It is preferably within the range of 4;)%. When the reinforcing polymer (A) is smaller than 5%, the reinforcing effect is =11- and when it exceeds 45%, the orientation of the reinforcing polymer (A> decreases, and the characteristics of the present invention are expressed. I can't.

The intrinsic viscosity used in the present invention means that the concentration of reinforcing polymer (△) in 100% sulfuric acid, methanesulfonic acid, or chlorosulfonic acid is 0.2! ? / 100cc
After dissolving so that
It is nh. When the reinforcing polymer (Δ) is dissolved in any of the above solvents, the lowest value among them is taken as the intrinsic viscosity of the reinforcing polymer (Δ).

The effects of the present invention will be illustrated below with examples, and the percentages in the examples are based on weight unless otherwise specified. fiber·
The mechanical properties of the film were measured at 1 min per minute for a sample length of 4 cm.
Measurements were taken at an elongation rate of 0%.

Example 1 As a reinforcing polymer (A), poly-p-phenylenebenzothiazole (abbreviated as PPBT) was polymerized according to a conventional method, and a polymer having an intrinsic viscosity of 4.1 in a methanesulfonic acid solvent was obtained. Obtained.

71 helix polymer (B) was prepared by adding 3,4'-diaminodiphenyl ether (50 mol%) and para-phenylene diamine (50 mol%) to N-methylpyrrolidone at a concentration of 6%, and placing it in a dry nitrogen atmosphere. After cooling to 5°C, prephthalic acid dichloride powder (100 mol%) was immediately added to the solution with vigorous stirring, a polymerization reaction was carried out at 35°C for 1 hour, and this was dissolved in water. It was precipitated and neutralized. Hereinafter, this polymer will be abbreviated as PPOT-50. ηinh of P P OT-50
was 3.6 in sulfuric acid solvent. PPBT and PPOT
-50 was dissolved in methanesulfonic acid at a component ratio of 30/70 to create a polymer with a total polymer concentration of 6%.

The polymer composite solution exhibited optical anisotropy at room temperature, and the temperature at which it transitioned from anisotropy to isotropy (phase transition temperature) was 65°C.

The polymer solution was forced into a plunger and extruded through an air space into a coagulation bath at room temperature. T-die has slit width 0
．． 3m was used.

The coagulation bath was 60% methanesulfonic acid at 60°C.

The polymer solution was measured using a melting point measuring device (YANAGIMOTO).
The solidified film, which was confirmed to undergo apparent optical isotropy during the solidification process, was thoroughly washed with water and neutralized with an aqueous sodium hydroxide solution for an additional 24 hours. The film was placed in a fixed frame, air-dried, and then stretched to obtain a uniaxially oriented film at a temperature of 3508°C and 470°C, respectively, at a stretching ratio equal to the maximum stretching ratio multiplied by 0.8.

The mechanical properties of the film are: film thickness (μm) / modulus (GPa) / elongation (%) 7 strength (GPa) =
It was 21/121/1.2/1.1.

Examples 2 to 4 In Example 1, the slit width of the doctor knife was set to 50
Films were formed under the same conditions except that the tiles were changed to 0 μm tiles, 800 μm tiles, and 1200 μm tiles to obtain -axis oriented films.

The mechanical properties of the film were as shown in Table 1, and good ones were obtained.

Table I Comparative example of mechanical properties of PPBT/PP0T-50 (30/70) film 1.2 PPBT/PP0T made in the same manner as in Example 1
-50 polymer solution with 10% methanesulfonic acid aqueous solution,
It was immersed in a coagulation bath at a temperature of 30°C. The polymer solution is
It exhibited only optical anisotropy in the coagulation bath, but no apparent optical isotropy. The final mechanical properties of the film extruded with a T-die of 0.3 mm are: film thickness (μm)/modulus/elongation (%)7 strength (GPa) =25/72/
It was 2.0/0.78.

The product extruded from T-die 1.2mm was not stretched enough after drying, and the mechanical properties were -15 = Modulus (GPa) / Elongation (%) 7 Strength (GPa)
=48/1.5/0.43, which was poor.

Patent applicant: Institute of Technology Director

Claims (1)

[Claims] A reinforcing polymer (A) consisting of a polyazole having a substantially rod-like skeleton and a matrix polymer (B) having fusion properties.
) is introduced into a coagulation bath and formed into a film, in which the polymer solution exhibits optical anisotropy, and the polymer solution exhibits optical anisotropy. A method for producing a polymer composite, characterized in that a polymer solution is immersed in a coagulation bath and then post-solidified via an apparently optically isotropic phase.