JPS6157346B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to novel polymer composites. More specifically, the present invention relates to a polyamide-based polymer composite reinforced with a specific and small amount of reinforcing molecules and a method for producing the same. The properties of polymer materials are determined by the primary structure related to the chemical structure, such as the binding energy, degree of free rotation, symmetry, stereoregularity, and degree of dipole polarization of the main chain constituting the polymer, and the crystal structure determined by the molding process. , is mainly determined by secondary structure related to polymer interactions such as orientation. Therefore, there are naturally limits to the properties that can be obtained from a single polymer material. In order to overcome this limitation, various composites have been studied and developed. Plastics (FRP) using fibrous substances mainly made of glass fiber as reinforcement materials, calcium carbonate,
Plastics using inorganic fillers such as mica,
A typical example is rubber filled with carbon. Particularly because of its versatility and industrial and economical advantages, the above-mentioned FRP has been making rapid progress and development in recent years. However, the following problems have been pointed out with FRP, and it has been a long time since the industry began searching for solutions to these problems. (1) Devices such as screws are significantly worn out in the FRP chip manufacturing process and molding process. (2) In the above process, the glass fibers are broken into short pieces and a considerable amount is powdered. The function that should be fulfilled as long fibers is significantly diminished. (3) When trying to effectively utilize long glass fibers, they cannot be uniformly dispersed in plastic. It is extremely difficult to reduce the diameter of glass fibers to a desired degree. (4) For the reasons mentioned above, it is generally said that 30% or more of the glass fiber used in FRP needs to be mixed in order to achieve a normal reinforcing effect. (5) During molding, since the glass fibers are oriented, anisotropy is added to the physical properties of the resulting molded product. (6) Molding efficiency is low due to the use of glass fiber, which is a macroscopic reinforcing material. (7) The surface condition of the molded product obtained is not good. (8) The form of the molded product is also limited to those with a certain degree of thickness, such as blocks and sheets. It is impossible to mold into thin or thin objects such as fibrous or film-like objects. Overview Problems such as those mentioned above are inherent in or accompany FRP. Despite industry efforts to resolve the issue, significant results have not yet been achieved. In recent years, there has been no development of new polymers, and there has been active research into so-called multicomponent polymers such as polymer blends and block copolymers, in which many existing polymers are applied for specific purposes.
However, no reinforcing material with excellent mechanical properties such as strength and elastic modulus has yet been found. In view of the above-mentioned current state of plastic technology reinforced with FRP and other macroscopic fibrous materials, the present inventors have conducted intensive studies on multi-component polymer composites that can overcome the drawbacks, and have found that Mechanical properties of a polymer composite obtained by uniformly dispersing a small amount of a polymer having a specific rigid aromatic polyamide molecular chain into an aliphatic polyamide having a flexible molecular chain. The present inventors have discovered that this can be significantly improved, and have completed the present invention. The purpose of the present invention is to uniformly disperse a substantially small amount of an aromatic polyamide having a specific rigid molecular chain in an aliphatic polyamide matrix, thereby improving the inherent injection moldability and spinnability of the matrix. The object of the present invention is to provide a polymer composite having improved mechanical properties such as breaking strength, yield strength, and elastic modulus without impairing moldability and processability such as film moldability, and a method for producing the same. (1) The molecular chains constituting the polymer have the following general formula -NH-Ar ₁ -NH- ......() -CO-Ar ₂ -CO- ......() (However, Ar ₁ is

[Formula] Ar ₂ is

[Formula] In which, X in Ar ₁ represents a group selected from the group consisting of alkyl, alkoxy, and halogen groups, and up to 20 mol% of Ar ₁ and/or Ar ₂ is another group having an extended chain bond. It may be substituted with a divalent para-directing group. ) is an aromatic polyamide with a logarithmic viscosity of 0.5 or more and is composed of repeating units shown in 2) Production of a polymer composite, characterized in that the aromatic polyamide and the aliphatic polyamide are simultaneously dissolved in a solvent in a compatible state, and then precipitated in a non-solvent coagulation solution for both of the polymers. The gist is the law. Hereinafter, the configuration of the present invention, embodiments, and effects will be explained in more detail. The substituent X in the 3,3'-disubstituted or 4,4' biphenyl group of Ar ₁ must not be a reactive substituent that induces branching and crosslinking of the polymer, e.g. Examples include lower alkyl groups such as methyl, ethyl and isopropyl groups, lower alkoxy groups such as methoxy and ethoxy groups, halogen groups such as chloro, bromo and fluoro groups, and substituents such as cyano and nitro groups. Preferably a methyl group, a methoxy group,
Those having a halogen group substituent are used. Up to 20 mol% of Ar ₁ and Ar ₂ may be substituted with other divalent para-directing groups having extended chain bonds, but is substantially coaxial, e.g. 1,4-phenylene, or e.g. 1,5-naphthylene,
A bond that extends the molecular chains of parallel and oppositely oriented groups such as trans-1,4-cyclohexylene. Specific examples include 1,4-phenylene, 1,5-naphthylene, 2,6-naphthylene,
trans-1,4-cyclohexylene, 2,5-
Pyridylene, 4,4'-biphenylene, trans,
Trans-4,4'-bicyclohexylene, trans-vinylene, ethynylene, 1,4-phenylene group bonded by an azo or azoxy group, etc. are listed, and these groups may have a substituent. . Aromatic polyamides whose molecular chains constituting the polymer are composed of repeating units () () of the above general formula are homogeneous polyamides composed only of repeating units () () or polyamides containing up to 20% of Ar ₁ and/or Ar ₂ . Grafting a rigid homo- or copolyaromatic polyamide molecular chain consisting of repeating units (), () onto an aliphatic polyamide molecular chain which is a copolyamide or matrix substituted with other divalent para-orienting groups having chain bonds. It means a modified aliphatic aromatic polyamide bonded by copolymerization in a type or block type, and the copolymerization ratio may be arbitrarily selected. These high molecular weight polymers are manufactured by conventionally known methods. That is, homo- or copolyaromatic polyamides can be produced by a method in which the corresponding aromatic dicarboxylic acid is first induced into an acid halide, acid imidazolide, or ester, and then reacted with the corresponding aromatic diamine, or by a method in which an amino group is induced into an isocyanate group. A method of subsequent reaction with carboxylic acid is used. Aliphatic block or graft copolymerized polyamides can also be reacted with monomers corresponding to aliphatic polyamide polymers in the presence of aromatic polyamide polymers, or by reacting them with monomers corresponding to aliphatic polyamide polymers in the presence of aromatic polyamide polymers. The method described below in which a monomer corresponding to an aromatic polyamide polymer is reacted is also used. The type of polymerization may be arbitrarily used depending on the purpose, such as interfacial polymerization, solution polymerization, or melt polymerization. η _ioh (logarithmic viscosity: per a solution of 0.5 g of polymer dissolved in 100 ml of concentrated sulfuric acid
(value measured by a conventional method at 25°C) is required to be 0.5 or more, preferably 1.0 or more; if it is less than 0.5, the reinforcing efficiency will deteriorate and is not preferred. The aliphatic polyamide of the reinforced matrix polymer used in the present invention includes 6-nylon, 6.6
- Refers to polyamides such as nylon, 6,10-nylon, and 12-nylon, and their respective copolymers and derivatives. The polymer composite of the present invention has a rigid aromatic polyamide having a specific molecular structure, which is a feature of the present invention, in the aliphatic polyamide of the above-mentioned matrix. In other words, optical microscopy shows that the rigid aromatic polyamide acting as a reinforcing material in the aliphatic polyamide matrix is aggregated in the form of sea islands or in certain areas. It is characterized by the fact that there is no A specific method for confirming this is simply by melting the composite and then rapidly cooling it to make a thin sample piece, and then observing it with the naked eye or an optical microscope, and confirming that virtually no opaque areas or sea-island-like agglomerated areas are observed. , or more precisely, when the melt of the complex is observed under polarized light passing through the analyzer crossed at 90°, confirmed by the virtual absence of areas or aggregates that change the dark field to bright field. Should. One indicator of polymer-polymer compatibility is that the mixing energy becomes negative, but polymers generally have an extremely small entropy term, and the free energy of mixing is mainly determined by the enthalpy of mixing. Since the enthalpy is positive in many cases, including low-molecular liquids, polymers are generally not compatible with each other except in special cases. Even in the past, there have been few examples of practical polymer-polymer compatibilization in the microscopic region. Under such circumstances, the present inventors investigated a method of microscopically uniformly dispersing rigid aromatic polyamide in the aliphatic nylon matrix, and found that aromatic polyamide with a specific molecular structure By selecting , they succeeded in microscopically homogeneous and uniform dispersion in aliphatic nylon, and based on this knowledge, they completed the method of the present invention. The polymer composite of the present invention is a rigid aromatic polyamide having a specific structure, that is, the main molecular chain forming the polymer is -NH-Ar ₁ -NH- ... () -CO-Ar ₂ -CO - It can be obtained by simultaneously dissolving an aromatic polyamide consisting of the repeating units () and an aliphatic polyamide in a solvent in a compatible manner, and then precipitating them in a non-solvent coagulating liquid. Naturally, the solvent used needs to be a solvent that dissolves both of the above polyamides. For example 92% by weight
The above-mentioned inorganic acids such as sulfuric acid, chlorosulfuric acid, and fluorosulfuric acid, or mixtures thereof are suitable. Organic solvents generally have poor solubility and are not preferred. In consideration of economy and solubility, sulfuric acid of 98% by weight or more is particularly preferred. In the method for producing a polymer composite of the present invention, the method of simultaneously dissolving both polyamides in a solvent is the method of first dissolving the aromatic polyamide in a solvent and then adding and dissolving the aliphatic polyamide, or vice versa. Any method may be used, such as the following procedure, or a method in which solutions of each polyamide separately dissolved in a solvent are mixed together, and they may be carried out in a batch or continuous manner. A simple way to check whether the above-mentioned polyamides are compatible in a solvent is to check the transparency of the solution. To be exact, the solution is 90
Observe under polarized light passing through an analyzer that intersects at 100 degrees, and check whether there is an island component that resolves the dark field into the bright field. If they are not compatibilized, the solution in which both polyamides are dissolved is opaque, and when the dope is observed under a polarizing microscope, islands of aggregated aromatic polyamides are observed, and the island portions exhibit optical anisotropy. Converts dark field to bright field. A composite obtained by precipitation from a solution in which such an aromatic polyamide is aggregated is opaque even when melted, and has no reinforcing effect on the molded article obtained thereby. The composite obtained by precipitation from a compatible solution is transparent even when melted, and from this fact, when precipitated from a compatible solution with a non-solvent coagulation solution, both polyamides are homogeneously miscible. It is thought that they will precipitate simultaneously while maintaining their state. The liquid for precipitating and coagulating the compatible solution may be any liquid that does not dissolve the two polyamides, such as pure water, water containing a high concentration of salt, an aqueous liquid such as dilute sulfuric acid, or a liquid that is miscible with water. There are aqueous organic solvents such as methanol, ethanol, and ethylene glycol, which may be selected arbitrarily. The shape of the composite obtained by precipitation may be any shape such as flake, fibril, film, rope, or fiber. The compatibility of both polyamides in a solution depends on the type and concentration of the solvent used, the mixing ratio of aromatic polyamide and aliphatic polyamide, the concentration of the polymer in the solution, the temperature of the solution, the intrinsic viscosity of the aromatic polyamide, etc. It's different. One example will be explained with reference to the accompanying drawings. The drawing shows the intrinsic viscosity as aromatic polyamide
3.5 Ar ₁

[Formula] Ar ₂ is

Polyparaphenylene 3,3'-dimethyl 4,4'-biphenylene dicarboxamide of [formula],
6-nylon as aliphatic polyamide at the same time as 3
FIG. 2 is a phase diagram at 25° C. of a solution dissolved in concentrated sulfuric acid at a concentration of species. In the figure, the horizontal axis represents the weight percent of the aromatic polyamide component in both polyamides, and the vertical axis represents the weight percent concentration of both polyamides in the sulfuric acid solvent solution. In the figure, 1 is the compatibility critical curve of the solution obtained using 99.5% by weight, 2 is 98% by weight, and 3 is 94% by weight of sulfuric acid as a solvent, and the area below the curve is above the compatibility region. The region is an incompatible phase separation region. Although not shown in the figure, a solution obtained using less than 92% by weight of concentrated sulfuric acid as a solvent is not compatible throughout the entire region, and when the concentration of aromatic polyamide is 30% by weight or more, 100% by weight Even if sulfuric acid is used in an amount greater than 1% by weight, and the temperature of the solution is raised to a temperature at which polyamide decomposition occurs, no solution is found in the compatible region. When the intrinsic viscosity of aromatic polyamide increases,
The critical compatibility curve moves downward and the compatibility region narrows,
As the temperature of the solution increases, the critical curve moves upward and the compatible region tends to widen. The critical curve also varies somewhat depending on the type of aromatic polyamide and the type of aliphatic polyamide. If the proportion of the aromatic polyamide in both polyamides exceeds 30% by weight, the compatibility in the solution will almost disappear, so the proportion should be 30% by weight or less, preferably 25% by weight or less. be. The polymer composite of the present invention can be used to form fibers, films, sheets, tapes, etc. without impairing the inherent moldability and processability of the aliphatic polyamide matrix.
It is possible to process composite materials reinforced with conventional macroscopic reinforcing materials such as fibers into shapes that are almost impossible with fiber-reinforced plastics, or to process block-shaped molded products.
The obtained molded product has excellent mechanical properties such as breaking strength, yield strength, and elastic modulus. To mold the polymer composite into the desired molded product,
For example, there are conventional molding methods such as melting the composite and extruding it, injection, roll, or cast molding, and redissolving the composite in a solvent and then wet or dry molding. During molding, additives such as plasticizers, light and heat stabilizers, and inorganic fillers can be used in combination, or the aliphatic polyamide can be further blended, and the resulting molded product can be optionally uniaxially or Biaxial stretching is also possible. The polymer composite of the present invention has a high degree of reinforcing effect on mechanical properties not found in conventional polymer composites, is highly versatile, and has significant industrial effects. The present invention will be explained in more detail below using Examples. In the examples, composition ratios and percentages are expressed in parts by weight and weight % unless otherwise specified. Unless otherwise specified, mechanical properties such as fracture, yield strength, and elastic modulus of molded products are measured using a gauge length of 25 mm after the test piece has been placed in an atmosphere at a temperature of 25°C and a relative humidity of 65% for at least 24 hours. Tensile test was carried out at a tensile rate of 10% elongation/min.
This is a conversion of the cross-sectional area before the tensile test, and is obtained by averaging the values measured on 20 different test pieces. Also, the logarithmic viscosity (η _io
h ) is a value measured by a conventional method at 25° C. for a solution of 0.5 g of polymer dissolved in 100 ml of concentrated sulfuric acid. Example 1 Terephthalic acid chloride and 3,3'-dimethylbenzidine (orthotolidine) were polymerized by a conventional method in a mixed solvent of N-methylpyrrolidone and dimethylacetamide containing lithium chloride to produce Polymer A with η _ioh 3.5. Weighed 0.6, 1.0, 2.0, and 4.1 g of this Polymer A, added 1000 g of 99.8% sulfuric acid to each, and dissolved them completely, then added 19.4, 19.0, 18.0, and 16.3 g of 6 nylon chips in the above order. , and further stirring to obtain clear solutions containing 3, 5, 10, and 20% of Polymer A, respectively, based on the total polymer weight. Next, this transparent solution was poured into pure water under stirring to cause precipitation, and the precipitate was filtered, thoroughly washed with hot water at 90°C, and vacuum-dried at 80°C to obtain a flaky composite. These composites were pre-pressed at a pressure of 100Kg/cm ² at room temperature, then an appropriate amount was weighed and placed in a mold.
The mixture was allowed to stand at 260° C. for 8 minutes under a N ₂ stream to melt.
Next, after pressing at the same temperature and under a pressure of 100Kg/cm ² ,
A transparent rectangular sample with a thickness of 1 mm, a length of 50 mm, and a width of 30 mm was obtained by quenching with cold water. From these samples, strip-shaped test pieces with a width of 5 mm were cut out and used as test pieces for measuring physical properties. The physical property measurement results are shown in Table 1.

[Table] The comparative example shows the physical properties of a test piece in which 6-nylon flakes were treated in the same manner except that Polymer A was not included. Example 2 Terephthalic acid chloride and 3.3' dimethoxybenzidine (ortho-dianisidine) were polymerized in N-methylpyrrolidone containing calcium chloride to polymerize three types of polymer B with η _ioh 1.2, 1.9, and 4.6. 3.3 g of these polymers B were added to 98.5% sulfuric acid with 43.8 g of nylon 6 in the same manner as in Example 1.
Dissolved in 1000g, 7% based on total polymer weight
A clear solution was obtained containing Polymer B of . This solution was precipitated in water, then washed and dried to obtain a composite. This composite was molded in the same manner as in Example 1, test pieces were cut out, and the physical properties were measured. Second result
Shown in the table.

[Table] For comparison, η _ioh 2.4 for total polymer weight
An opaque solution containing 7% of Polymer B (concentration of the total polymer in the solution) of 11% (observation with a polarizing microscope shows phase separation, and the islands are optically anisotropic, changing dark field to bright field). ). This solution was treated in the same manner as in Example 2 to obtain a test piece, and its physical properties were measured. The result is breaking strength
It had a yield strength of 5.8 Kg/mm ² , a yield strength of 4.5 Kg/mm ² , and an elastic modulus of 137 Kg/mm ² . Example 3 A composite containing 5% of Polymer A obtained in Example 1 was
The monofilament was extruded at 240°C with a plunger through a spinneret having one pore of 1.0 mmφ to obtain a monofilament. This monofilament was stretched 3.5 times at 180°C. The obtained fiber had the physical properties shown in Table 3. The physical properties of the comparative example were obtained by treating only 6-nylon, which does not contain polymer A, in the same manner.

[Table] Example 4 Orthotolidine 85 mol% as diamine component,
A diamine containing 15 mol% of paraphenylene diamine and terephthalic acid chloride were polymerized in N-methylpyrrolidone containing calcium chloride to obtain η _ioh 2.1,
Copolymer C of 3.9 was obtained. 6.6-Make four separate solutions of 30 g of nylon dissolved in 1000 g of 96% sulfuric acid, and add η _ioh 2.1,
1.25 g and 4.70 g of Copolymer C of 3.9 were added and dissolved overnight to create four clear solutions containing 4% and 13.5% of Copolymer C based on the total polymer weight. When these solutions were observed under a polarizing microscope, they were found to be uniformly dissolved and no phase separation was observed. This clear solution was allowed to flow down into room temperature pure water that was being vigorously stirred to cause precipitation. Next, this precipitate was separated, thoroughly washed with boiling water, and then vacuum dried at 60°C.
A flaky composite was obtained. The composite was pre-pressed at a pressure of 100Kg/ ^cm2 at room temperature, then placed in a mold and melted at 280℃ for 6 minutes under a _N2 stream, then at the same temperature and under a pressure of 100Kg/ ^cm2 . Press for 30 seconds,
Next, quench with cold water to a thickness of 1 mm, length of 50 mm, and width of 30 mm.
A transparent sample was obtained. From these samples, strip-shaped test pieces with a width of 5 mm were cut out and used as test pieces for measuring physical properties. The physical property measurement results are shown in Table 4.

[Table] The comparative example shows the physical properties of a test piece obtained by treating only nylon 66, which does not contain polymer C, in the same manner as in Example 4. Example 5 13.3 g of orthotolidine was dissolved in a mixed solvent of 350 ml of hexamethylphosphoramide containing calcium chloride and 350 ml of N-methylpyrrolidone, and then 13.6 g of terephthalic acid chloride was added and polymerized. The polymer isolated from a part of this polymerization solution has η _oh
It had 1.26. Next, 29.2 g of adipoyl chloride, 20.2 g of hexamethylene diamine, and triethylamine were added to this polymerization solution and polymerized to obtain 65 g of a block copolymer of 6,6-nylon and aromatic polyamide. This block copolymer contained 33% by weight of aromatic polyamide component. This copolymer was mixed so that the 6,6-nylon and aromatic polyamide components were 1, 3, 5, and 10%, test pieces were made in the same manner as in Example 4, and the physical properties were measured. The results shown in Table 5 were obtained.

【table】 [Brief explanation of the drawing]

The drawing is a compatibility/incompatibility phase diagram at 25° of a solution in which aromatic polyamide and aliphatic polyamide are simultaneously dissolved in concentrated sulfuric acid.

Claims (1)

[Claims] 1. The molecular chains constituting the polymer have the following general formula -NH-Ar ₁ -NH- ...... () -CO-Ar ₂ -CO- ...... () (However, Ar ₁ is [Formula ]Ar ₂ is [Formula], and X in Ar ₁ represents a group selected from the group consisting of an alkyl group, an alkoxy group, and a halogen group.Also, Ar ₁ or/and Ar ₂
Up to 20 mol% of the divalent para-directing group may be substituted with other divalent para-directing groups having extended chain bonds. ) A polymer composite comprising an aromatic polyamide having a logarithmic viscosity of 0.5 or more and consisting of repeating units shown in 2. The polymer composite according to claim 1, wherein the substituent X of Ar ₁ is a group selected from the group consisting of a methyl group, a methoxy group, and a halogen group. 3 Aliphatic polyamide is 6-nylon, 6.6-
The polymer composite according to claim 1, which is nylon. 4. The polymer composite according to claim 1, wherein the repeating units () () of the molecular chain are in an amount of 25% by weight or less of the amount of the polymer composite. 5 The molecular chains constituting the polymer have the following general formula -NH-Ar ₁ -NH- ...... () -CO-Ar ₂ -CO- ...... () (Ar ₁ is [Formula], Ar ₂ is [Formula] ], where X in Ar represents a group selected from the group consisting of an alkyl group, an alkoxy group, and a halogen group.Also, Ar ₁ or/and Ar ₂
Up to 20 mol% of may be substituted with other divalent para-directing groups having extended chain bonds. ) A polymer composite in which an aromatic polyamide having a logarithmic viscosity of 0.5 or more and an aliphatic polyamide, which are composed of repeating units shown in manufacturing method. 6. The method for producing a polymer composite according to claim 5, wherein the solvent is concentrated sulfuric acid containing 98% by weight or more of H ₂ SO ₄ .