JPH0776656A - High polymer composite and production thereof - Google Patents

Abstract

PURPOSE:To obtain the composite capable of remarkably improving ductility and impact strength in addition to improvement of strength and rigidity by covalently bonding a rigid chain part of the resultant rigid polymer to a flexible molecular chain of a thermoplastic polymer. CONSTITUTION:This composite consists of (A) a thermoplastic polymer as a matrix component and (B) a rigid polymer having a rigid-chain structure as a reinforcing component. The composite is obtained by blending (C) a monomer for forming the component B with the component A and/or the component A and (A') a thermoplastic polymer compatible with the component A at a specific ratio, polymerizing the component B in melted and kneaded state without any solvent and, simultaneously, covalently bonding the rigid chain part of the component B to a flexible molecular chain of a part of the component A and component A' by ester interchange, amide exchange, ester-amide exchange, then, melting and mixing the residual component A while suppressing reaction between different molecules. In this composite, the rigid chain part of the component B is finely dispersed as micro fiber on a molecular level into the component A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer composite in which a matrix made of a thermoplastic polymer is dispersion-reinforced with a rigid polymer at a molecular level, and a method for producing the same.

[0002]

2. Description of the Related Art Generally, the performance peculiar to polymer materials is expressed by a higher-order structure, which is affected by the primary structure such as molecular weight, molecular weight distribution, crystallinity and orientation. Above all, it depends largely on the molecular structure. Therefore, macrofiber-reinforced composite materials have heretofore been used as a method for overcoming the naturally occurring limitation of mechanical properties.

Carbon fibers, high-strength, high-strength filament fibers used for macro fiber-reinforced composite materials,
Examples include glass fiber and aramid fiber. However, these fibers are usually aggregates of fibrils and microfibrils, and have defects that are sources of microcracks incorporated in various places. For example, the molecular chain end, the microfibril end, or each fiber end, which is the propagation path of the fracture crack, receives a stress higher than the average stress in the structure subjected to the external force, that is, causes stress concentration. Further, since the filament diameter is about 10 μm, the adhesion at the fiber-matrix interface must be sufficiently strong in order to uniformly distribute the external stress between the oriented fibers and bring out the ultimate performance of the fibers.

With respect to such structural defects of macrofibers and the problem of interfacial adhesion, the ripple effect of a fatal defect is reduced and the strength is improved by reducing the diameter. In other words, by making the diameter finer, it is possible to prevent stress from being concentrated locally,
Further, the aspect ratio L / D (L and D are the length and diameter of the reinforcing fiber) becomes large, the contact surface area increases, and the problem of adhesion at the interface with the matrix molecules is reduced. And its ultimate form is a rigid polymer dispersed in a matrix, and when the molecular diameter of the rigid polymer is D, the critical aspect ratio is easily achieved, and breakage is a relationship that the covalent bond of the molecular chain is broken. If the adhesion of the interface with the matrix molecule is sufficient, the theoretical strength of the molecule can be expressed. Further, the effectiveness of the rigid linear structure for expressing strength is attributed to the rigidity of the molecular chain derived from the molecular structure and the fact that the generated crystal does not fold the molecular chain and has high strength in the molecular chain direction. In the case of a normal folding chain structure, the folded portion becomes defective. Further, since the amorphous part has a small number of covalent bonds filled in a unit cross-sectional area, it serves as a propagation path for a fracture crack, which is also advantageous for the rigid polymer to exert strength. Therefore, when the molecular chain of the reinforcing polymer substance has rigidity exceeding a certain limit,
If they can be dispersed microscopically and uniformly in the matrix polymer, the addition of a small amount of the reinforcing polymer can be expected to improve various mechanical properties without a practical reduction in processability.

[0005]

SUMMARY OF THE INVENTION Conventionally, from such an idea, Japanese Patent Publication No. 61-5500 and Japanese Patent Publication No. 55-500.
No. 440 proposes the concept of polymer composite. These conventional polymer composites are basically a method of uniformly mixing a polymer and a polymer using a solvent,
It is difficult to mix and disperse such polymers in a very uniform state at the present technical level, and in many cases, the diameter of the reinforcing material (lump of the rigid polymer) exceeds usually several μm. In addition, it is essential to use a solvent, and there is a drawback in that a solvent that is not compatible with the solvent cannot be used basically. Further, the use of a solvent is currently subject to legal regulation from various viewpoints, and it is considered that a production method that does not use a solvent is basically suitable. Therefore, the present invention, by the production method without using a solvent, the reinforcing material (rigid polymer) can be uniformly dispersed at the molecular level,
It is another object of the present invention to provide a composite which can improve the bondability of the molecular chain ends and the adhesiveness between the microfiber and the matrix and eliminate the disadvantageous conditions for destruction.

[0006]

That is, the present invention provides a rigid polymer (B) having a rigid linear structure as a reinforcing component.
And 2 of thermoplastic polymer (A) as matrix component
In a polymer multi-component composite material comprising one or more polymers, at least part of the reinforcing component is a thermoplastic polymer (A) and / or a thermoplastic polymer (A ′) compatible with the polymer (A). A rigid polymer (B) is a copolymer, and the rigid straight chain portion in the reinforcing component is finely dispersed in the matrix component (A) as a microfiber at a molecular level, and the thermoplastic polymer (covalently bonded thereto). A) and / or
Provided is a complex in which the flexible molecular chain portion of (A ') is dissolved in the matrix component (A) substantially uniformly.

[0007]

According to the present invention, as shown in FIG. 1, a rigid polymer can be finely dispersed in a matrix as a microfiber at a molecular level by solvent-free and melt mixing, and at the same time, a reinforcing component can be obtained. The rigid polymer, which is a rigid polymer, is copolymerized with a flexible molecular chain of the same component as the matrix or a compatible component, to further reduce the stress concentration source at the molecular chain end of the rigid polymer, and yet to anchor the flexible molecular chain into the matrix. Since the effect can strengthen the adhesiveness at the interface between the reinforcing fiber and the matrix, even if a small amount of a rigid component is added, the strength and rigidity are improved, and the ductility and impact resistance (breakage) that could not be achieved in the past were achieved. Energy required to express the stress-strain curve occupied area)
Can be dramatically improved. Further, according to the present invention, even if a small amount of a rigid component is blended, not only the strength and the rigidity can be improved, but also the ductility, which was not possible by the conventional concept, can be dramatically improved.

In the present invention, two types of polymers are used, namely,
It is classified into a thermoplastic polymer having a flexible molecular chain and a rigid polymer having a rigid molecular chain structure. The rigidity referred to in the present invention means that the bond forming the polymer chain is strong,
It means that the occupied cross-sectional area of the polymer chain is small and the polymer chain is composed of a molecular structure with a small elongation. If it is applicable to this definition, it can be said to be rigid, but if it is expressed more specifically, it can be expressed by both the theoretical crystal elastic modulus Ec and the theoretical strength σb at break. The theoretical crystal elastic modulus Ec and the theoretical strength σbc are defined as follows. Theoretical value of crystal elastic modulus Ec and theoretical strength at break σbc
How to obtain: First, consider one polymer chain. A force F is applied to a polymer chain having a cross section S and a length L. At this time △ L
(= L−L ₀ ), the tensile modulus E is E = σn / εn = (F / S) / (ΔL / L) (1) [where E is the tensile modulus and σn is Tensile stress (σn = F /
S) and εn represent elongation strain and εn represents ΔL / L. ] Theoretical strength at break is .sigma.b is σb = Fmax / S = (k 1 D / 8) 1/2 / S (2) [ wherein, Fmax is the stress maximum, D is showing a binding energy.

When a rigid polymer is pointed out from the viewpoint of mechanical properties, it can be shown as follows from theoretical crystal elastic modulus, theoretical strength, tensile elastic modulus of actual fiber, and degree of achievement of tensile strength as currently available information. Will.

[0010]

[Table 1] Theoretical value Reached value Theoretical crystal modulus [GPa] 150 or more Tensile modulus [GPa] 100 or more Theoretical strength [GPa] 2.0 or more Tensile strength [GPa] 2.0 or more

An example of the rigid polymer satisfying the physical condition is a polymer having a repeating unit structure represented by the following (Chemical formula 1).

[0012]

[Chemical 1]

In the formula, all benzene rings may have a substituent such as an alkyl group or halogen. In the rigid polymer represented by such a chemical formula, the condition for being usable in the present invention is that the monomer is an aromatic hydroxy acid, or a wholly aromatic polyester in which aromatic diols and aromatic dicarboxylic acids are combined. Derivatives and monomers include aromatic amino acids, or wholly aromatic polyamides consisting of a combination of aromatic diamines and aromatic dicarboxylic acids and derivatives thereof, and modified to enhance the reaction activity of the functional groups of these monomers. Including those formed by using the applied one, p
-Polyoxybenzoyl (poly-p-benzoate) (Chemical Formula 3) using acetoxybenzoic acid and its derivative (Chemical Formula 2) as monomers, and poly-p- using p-acetamidobenzoic acid and its derivative (Chemical Formula 4) as monomers. In addition to benzamide and its derivative (Formula 5), poly (p-phenylene terephthalamide), polyazomethine, poly (p-phenylenepyromellitimide), polybenzobisoxazole, polybenzobisthiazole, polybenzoxazole and the like can be mentioned. .

[0014]

[Chemical 2] In the formula, X represents H, Cl, CH ₃ or C ₆ H ₅ .

[0015]

[Chemical 3] In the formula, X represents H, Cl, CH ₃ or C ₆ H ₅ .

[0016]

[Chemical 4] In the formula, X represents H, Cl, CH ₃ or C ₆ H ₅ .

[0017]

[Chemical 5] In the formula, X represents H, Cl, CH ₃ or C ₆ H ₅ .

The thermoplastic polymers (A) and (A ') used in the present invention are not included in the above rigid polymer category.
Typical polymers include polymers having an ester bond, an amide bond, or both in the molecular chain, which enhances the carboxyl group, amino group, hydroxyl group and their reaction activity at the molecular chain end. A polymer having a modified functional group is preferable, and examples of such a polymer include polyamides such as nylon 6 and nylon 66, polyesters such as polycarbonate, polyethylene terephthalate and polybutylene terephthalate.

Typical combinations of the thermoplastic polymer (A) and the compatible thermoplastic polymer (A ') are as follows. Aromatic nylon (trade name MXD-6: manufactured by Mitsubishi Gas Chemical Co., Inc.) can be mentioned for nylon 6 and nylon 66. Examples of polycarbonate include poly-ε-caprolactone, polybutylene terephthalate, and polyethylene terephthalate. Examples of polyethylene terephthalate include polyester carbonate and bisphenol A polycarbonate. Examples of polybutylene terephthalate include polybisphenol A-terephthalate and bisphenol A polycarbonate.

The polymer composite of the present invention is a rigid polymer.
(Corresponding to a rod-shaped reinforcing material) is finely dispersed at the molecular level, and the diameter of the cross section cut at right angles to its longitudinal direction is 0.0.
It is preferably 7 μm or less. The diameter of the cross section of the rod-shaped reinforcing material means the portion where the rigid polymer in the composite is gathered (the portion where the rod-shaped rigid polymer is dense in the matrix of the flexible polymer), cut at a right angle to the longitudinal direction, and cut. It means the diameter when the area of the cross section is corrected to a center circle.

As described above, the diameter of the cross section of the rod-shaped reinforcing member (rigid polymer portion) cut at right angles to the longitudinal direction is 0.07.
In order to have a thickness of not more than μm, it is preferable to use the characteristic manufacturing method of the present invention.

As the method of the present invention, a polymer multicomponent composite comprising two or more polymers of a rigid polymer (B) having a rigid linear structure as a reinforcing component and a thermoplastic polymer (A) as a matrix component. In manufacturing the material,
A monomer for forming the rigid polymer (B), a thermoplastic polymer (A) or a thermoplastic polymer (A) and a thermoplastic polymer (A ') compatible with the polymer (A) in a predetermined ratio. The rigid polymer (B) is blended and polymerized in a solvent-free, melt-kneaded state at the same time as the rigid polymer (B).
Rigid-chain portion and the thermoplastic polymer (A) and / or
It is characterized in that a part of the flexible molecular chain of (A ') is covalently bonded by transesterification, transamidation or transesterification, and then the remaining thermoplastic polymer is melt-mixed while suppressing intermolecular reaction. . Specific examples of the monomer for forming the rigid polymer include, for example, when the polymer is poly (p-oxybenzoyl), p-acetoxybenzoic acid, p-hydroxybenzoic acid chloride, phenyl p-hydroxybenzoate. , Poly (p−
Benzamide), p-acetaminobenzoic acid,
p-aminobenzoic acid chloride and the like can be mentioned.

In the present invention, it is particularly necessary to carry out polymerization in a melt-kneaded state without using a solvent. Specifically, the thermoplastic polymer (A and A ') and the monomer forming the rigid polymer (B) are melt-kneaded in a reactor or by a twin-screw extruder,
For example, when p-acetoxybenzoic acid is used as the monomer, the temperature is set to 250 to 300 ° C. to accelerate the exchange reaction with the thermoplastic polymer simultaneously with the polymerization of the monomer. The subsequent melt mixing of the remaining thermoplastic polymer (A) can be carried out at a temperature of 250 ° C. or lower at which the above reaction is suppressed to obtain the desired composite material. This process can be applied to continuous processes such as twin-screw extruders, and the first half of the cylinder is set to a temperature at which a predetermined polymerization reaction and exchange reaction occur, and the second half is set to a temperature at which such a reaction does not proceed. do it. For example, in the case of p-acetoxybenzoic acid, the rigid polymer (B) containing p-acetaminobenzoic acid as a monomer, polyoxybenzoyl, and poly (p-benzamide), the cylinder first half is 250 to 300.
A predetermined material can be obtained by setting the temperature to 250 ° C. and setting the latter half to a temperature at which the copolymer AB or A′-B and the thermoplastic polymer A melt at 250 ° C. or lower. Of course, as long as the method of the present invention is used, there is no restriction on the processing machine used for material adjustment according to the present invention.

At the time of the melt-kneading of the present invention, additives, polymerization initiators, etc. may be added if necessary.

[0025]

EXAMPLES The present invention will be described in more detail by way of examples. The present invention is not limited to these examples.

Example 1 In a reactor equipped with a stirrer, a nitrogen introducing tube and a distilling tube, 650 g of nylon-6 was placed and melted at 225 ° C. under a nitrogen atmosphere. 50 g of p-acetoxybenzoic acid was sequentially added thereto, and both were uniformly mixed. The temperature was gradually raised to 260 ° C. to start the reaction. Kneading reaction was carried out at this temperature for 4 hours to proceed deacetic acid polymerization and ester-amide exchange reaction. At this time, by reducing pressure, acetic acid and water produced as by-products were removed to the outside of the system. Then, the temperature was raised to 210 ° C., and the polymerization was carried out for 12 hours in a nitrogen atmosphere. The reaction product thus obtained was ground and then washed with acetone and methanol. This reaction product nylon / POB (polyoxybenzoyl) (weight ratio 50/50) did not show optical anisotropy when melted under a polarizing microscope. In addition, it was confirmed that it melts at the melting point of nylon-6 or higher.

Example 1-1 Nylon / POB (50/50) reaction product 0.028
g, nylon-6 1.372 g (weight ratio 98/2)
A miniature injection molding machine (MINI-MAXMOLD
ER CS-183MMX, Custom Science
tific Instruments. INC. ) At 230 ° C. × 4 min, and both are uniformly blended. The nylon-6 / POB (weight ratio 99/1) composite obtained by blending was injection molded into a test piece mold from this miniature kneader to obtain a tensile test sample.

Examples 1-2 to 6 Nylon-6 / POB (weight ratio 98.5 / 1.5), (weight ratio 98/2), (weight ratio 9) in the same manner as in Example 1-1.
7.5 / 2.5), (weight ratio 95/5), (weight ratio 90 /
Each composite of 10) was adjusted and the sample for the tensile test was created.

The tensile test samples thus obtained were tested for tensile strength by the following method. Tensile tester (MINI-MAX TENSILE T
ESTER CS-183TE, Custom Sci
Entity Instruments. INC) Tension speed 0.566 cm / min Distance between test sample gauge lines L = 0.9 cm, diameter D = 0.
1587 cm, strain rate 0.629 / min, measurement temperature 22 ° C. The physical property measurement results are shown in Table 2, and the stress-strain curve of typical physical properties is shown in FIG.

[0030]

[Table 2]

As is clear from the above results, poly (p-
Oxybenzoyl) compounding at the molecular level dramatically improved the strength, elastic modulus, and elongation of nylon 6.

Example 2 Polycarbonate / polyoxybenzoyl (PC / PO
B) Polycarbonate, 30 g, and p-acetoxybenzoic acid, 30 in a reactor equipped with a stirrer, a nitrogen introduction tube, and a distillation tube.
g was added, the temperature was raised to 210 ° C. in a nitrogen atmosphere while stirring, and both were uniformly mixed. The temperature was gradually raised to 280 ° C. to start the reaction. A kneading reaction was carried out at this temperature for about 3 hours to advance deacetic acid polymerization and transesterification reaction. At this time, by flowing nitrogen, acetic acid and water produced as by-products were excluded from the system. The reaction product polycarbonate / POB (weight ratio 50/50) thus obtained melts at 240 ° C. at which the matrix polycarbonate melts.

Example 2-1 Polycarbonate / POB (50/50) reaction product (0.14 g), polycarbonate (1.26 g) was mixed with a miniature kneader (MINI-MAX MODELCS-1).
83MMX, Custom Scientific I
nstruments. INC. ), 240 ° C x 4
min. Knead and blend both uniformly. Polycarbonate / POB obtained by blending (weight ratio 95 /
5) The composite was injection molded into a test piece mold from this miniature kneader to obtain a tensile test sample.

Examples 2 to 2 Polycarbonate / POB was prepared in the same manner as in Example 2-1.
Each composite of (weight ratio 90/10) and (97/3) was prepared to prepare a sample for tensile test. Similarly, a sample for tensile test of polycarbonate was also molded for comparison. The tensile test sample thus obtained was subjected to a tensile test by the following method. Tensile tester (MINI-MAX TENSILE T
ESTER CS-183TE (CSI In
c. ) Tensile speed 0.566 cm / min Distance between sample marked lines L = 0.9 cm, diameter D = 0.158
7 cm strain rate 0.629 / min, measurement temperature 22 ° C. The physical property measurement results are shown in Table 3, and the stress-strain curve of representative physical properties is shown in FIG.

[0035]

[Table 3]

As is clear from the above results, poly (p-
It has been confirmed that the compounding of (oxybenzoyl) at the molecular level dramatically improves the strength, elastic modulus, and elongation of polycarbonate.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an internal structure of a microfiber-reinforced composite material according to the present invention.

FIG. 2 is a graph showing a stress-strain curve of only a matrix resin and a typical stress-strain curve of a microfiber-reinforced composite material (Example 1) according to the present invention in comparison.

FIG. 3 is a graph showing a stress-strain curve of only a matrix resin and a typical stress-strain curve of a microfiber-reinforced composite material (Example 2) according to the present invention in contrast.

Claims (3)

[Claims] 1. A polymer multi-component composite material comprising two or more polymers of a rigid polymer (B) having a rigid linear structure as a reinforcing component and a thermoplastic polymer (A) as a matrix component, wherein At least a part of the components is a thermoplastic polymer (A) and / or a thermoplastic polymer (A ') compatible with the polymer (A) and a rigid polymer (B).
The rigid linear portion in the reinforcing component is finely dispersed in the matrix component (A) as a microfiber at the molecular level, and is covalently bonded to the thermoplastic polymer (A) and / or ( A polymer composite characterized in that the flexible molecular chain portion of A ') is dissolved in the matrix component (A) substantially uniformly. 2. A rod-shaped reinforcing member formed of the rigid polymer (B) has a cross-sectional diameter of 0.0 at a right angle to the longitudinal direction.
The polymer composite according to claim 1, which has a thickness of 7 μm or less. 3. A process for producing a polymer multi-component composite material comprising two or more polymers of a rigid polymer (B) having a rigid linear structure as a reinforcing component and a thermoplastic polymer (A) as a matrix component. A predetermined ratio of the monomer for forming the rigid polymer (B), the thermoplastic polymer (A) or the thermoplastic polymer (A) and the thermoplastic polymer (A ') compatible with the polymer (A). In the solvent-free, melt-kneaded state, the rigid polymer (B) is polymerized, and at the same time, the rigid linear portion of the rigid polymer (B) and the thermoplastic polymer (A) and / or (A ′) A polymer composite characterized in that a part of the flexible molecular chains of the polymer are covalently bonded by transesterification, amide exchange or ester-amide exchange reaction, and then the remaining thermoplastic polymer is melt-mixed while suppressing intermolecular reaction. Manufacturing method .