JPH0225364B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a novel polymer composition in which carbon fibers (hereinafter abbreviated as CF) and an organic polymer are strongly integrated. Regarding the polymerization of vinyl monomers, various polymerization methods such as radical polymerization, ionic polymerization, and coordination polymerization are known. There are not necessarily many polymerization methods that are industrially easy, such as those that require the blending of polymers or water management during ionic polymerization. Furthermore, although non-catalytic polymerization methods that do not use a polymerization initiator have been reported for a few unique systems, they have been almost impossible to put into practical use from an industrial standpoint. In view of the above-mentioned current situation, as a result of intensive studies, the present inventors have discovered that a vinyl monomer capable of radical polymerization in the presence of a specific carboxylic acid monomer is brought into contact with CF as a third component. The present invention has been completed by discovering that it is possible to obtain a novel polymer composition that cannot be obtained by conventional methods, in which the polymerization activity of the polymer is significantly increased, the CF and the organic polymer are strongly integrated, and the granulation property is excellent. It came to this. Conventionally, the development of composite materials that mutually complement the properties of the constituent materials and create new effective functions by combining two or more types of materials has been actively conducted. When combined with useful inorganic compounds, it has been reported that a wide range of performance improvements, such as elastic modulus, heat distortion temperature, and electrical properties, have been achieved. However, when combining an organic polymer and an inorganic compound, the properties of the composite materials differ significantly, resulting in poor interfacial compatibility such as compatibility and adhesion, making it impossible to achieve sufficient composite effects. Moreover, inorganic fillers in the form of powder, in particular, have an essential drawback in that some of the physical properties inherent to the resin, such as toughness, cannot be avoided. To improve this point, a mechanochemical method involves grinding an inorganic compound in the presence of a reactive monomer to graft an organic polymer, and a radiation method involves irradiating an inorganic compound with high-energy radiation to graft an organic polymer. Attempts have been made to improve the interfacial affinity between organic polymeric substances and inorganic compounds using methods such as methods, but these require pulverization processes, radiation generation equipment, etc., resulting in complicated processes and a significant increase in manufacturing costs. There are major problems in terms of practicality. As a result of intensive studies on improving this point, the present inventors have developed a practical method for producing composites in which vinyl polymer is firmly integrated with various powdered inorganic compounds in the presence of a specific carboxylic acid monomer. Heading: Patent Application No. 56-35549 was filed earlier. after that,
As a result of further consideration, as an inorganic compound,
CF has particularly high polymerization activity and excellent interfacial cohesion,
Furthermore, the present invention was completed by discovering that not only powdered fine fibers but also relatively long fibers exhibit remarkable granulation properties. That is, the present invention is based on the following general formula (In the formula, R ₁ is H, an alkyl group having 1 to 15 carbon atoms,
COCY, halogen atom or phenyl group and its derivatives, R ₂ is H, alkyl group having 1 to 15 carbon atoms,
COOZ, halogen atom or phenyl group and its derivatives, R ₃ is H, alkyl group having 1 to 15 carbon atoms,
A halogen atom or a phenyl group and its derivatives, X, Y, and Z each represent H, NH ₄ or an alkali metal atom. ) or general formula (In the formula, R ₄ and R ₅ are each H, carbon number 1 to 15
represents an alkyl group, a halogen atom or a phenyl group, and derivatives thereof. ) in the presence of at least one carboxylic acid monomer represented by The present invention provides a method for producing a novel polymer composition in which characteristic CF and organic polymer are strongly integrated. Generally, when vinyl monomers are simply polymerized in the presence of an acid under temperature conditions that do not cause a thermal polymerization reaction, the polymerization rate remains at an extremely low level even after several days of polymerization time. On the other hand, according to the present invention, adding CF as a third component brings about a very specific polymerization activity,
Not only can a polymer with a high polymerization rate of practical value be obtained in a few hours, but also an extremely clean polymerization form without the formation of cullet due to gas phase polymerization. Furthermore, the present invention is characterized in that the interaction between the CF surface and the polymer applied by the method of the present invention goes beyond adhesion in the sense of simple adsorption, and is strongly integrated. It is at the point where it is done. In addition, it can be applied not only to fine powder CF but also to relatively long CF such as chopped strand fibers, which are normally difficult to process in a medium due to reduced cohesiveness, entanglement and agglomeration between fibers. This point can be said to be the great practical value of the present invention. To give an example of an embodiment in carrying out the present invention, an organic vinyl monomer and CF are suspended and dispersed in an aqueous medium under temperature conditions that do not cause a thermal polymerization reaction, and then a carboxylic acid monomer is added. By adding and stirring, an aqueous heterogeneous polymerization reaction is caused, and the surface of the CF is uniformly and firmly fixed with the vinyl monomer polymer at a high polymerization rate over a predetermined polymerization time. Can be done. At this time, it is an essential condition that the three components mentioned above are brought into contact with each other in coexistence, but it is not necessarily necessary to bring them into contact at the same time. That is, even if CF pretreated with a carboxylic acid monomer is used, a similar polymer composition can be obtained by the method of the present invention without adding a new carboxylic acid monomer during monomer polymerization. Can be done. Conventionally, a method for obtaining a similar polymer composition in the presence of hydrogen sulfite ions is known, but since a large amount of cullet from gas phase polymerization adheres and the product is extremely fine particles, washing, recovery, etc. are difficult. It has a disadvantage in terms of industrial practicality in that post-processing is not easy. Regarding these problems, the method of the present invention
By using a specific carboxylic acid monomer, a clean polymerization form with almost no cullet formation is achieved, and surprisingly, the resulting polymer composition has excellent granulation properties, making it easy to wash, recover, etc. This provides a method for obtaining a product with extremely easy post-processing. The specific carboxylic acid monomer used in the present invention has a carboxylic acid group as an active side that brings about polymerization activity, and has a CF
The presence of a double bond as an active side is essential to express strong bonding with the structural formula shown in the above general formula [] or [] which has both of these two types of functional groups. Compounds having the following can be applied. Specific examples include acrylic acid, methacrylic acid, crotonic acid, tiglic acid, cinnamic acid, maleic anhydride, and citraconic anhydride. In particular, acrylic acid, methacrylic acid, and crotonic acid exhibit remarkable granulation properties. It is also preferred because it also has high polymerization activity. These compounds can be used alone or in combination of two or more. The CF used in the present invention includes high-strength or high-elasticity CF made of polyacrylonitrile or its copolymer, CF made from petroleum high-temperature decomposition pitch, coal tar pitch, and coal depolymerized product,
Further examples include CF produced by a vapor phase growth method, and both carbonaceous and graphitic CF are applicable. Further, various types of CF may be subjected to a commonly performed surface oxidation treatment. A wide range of fiber lengths can be used, from a powdery one of about 0.1 mm to a chopped strand with a large aspect ratio of about 3 to 20 mm, and the fiber diameter is not particularly limited. All of the composites obtained by the present invention are obtained in the form of granules that have good interfacial adhesion and are easy to handle. In particular, when chopped strand-like CF is stirred in water or an organic solvent, the single fibers generally coagulate and are difficult to blend with resin, but according to the present invention, the excellent granulation By taking advantage of this property and adjusting the conditions, it is possible to obtain pellets of about 1 to 5 mm that are easy to handle and work. In particular, in the case of pitch-based CF, when the fiber length is about 1 mm or more, the CF itself is already flocculent and agglomerated, so it cannot normally be blended with resin, but when the formulation of the present invention is applied, extrusion or injection molding Since a pellet-like composite with good properties can be obtained, the present invention is extremely unique and has high practical value not only because of the interfacial effect but also as a method for adjusting the shape of the composite. Regarding the roving-like long fibers,
If left standing or under gentle stirring conditions,
The present invention can be applied and excellent interfacial effects can be obtained. As the vinyl monomer used in the present invention, any ordinary vinyl monomer that can be radically polymerized can be used, but among them, methyl methacrylate has a particularly high polymerization activity, and moreover, it has a high polymerization activity. It is particularly preferred because of its good coalescence properties. When a mixture of two or more monomers is used, it is preferable to use methyl methacrylate as one component, particularly from the viewpoint of polymerization activity. According to the present invention, the concentration of carboxylic acid monomer is about 0.05 to 100, based on the total weight of CF and monomer.
It is used in amounts of % by weight, preferably 0.1-50% by weight, particularly preferably 0.5-30% by weight. In most cases, it is preferable to increase the amount of carboxylic acid monomer as the monomer component increases. CF to use
The weight ratio of monomer or monomer mixture to can vary within a wide range, from about 500:1 to 1:
5, preferably about 50:1 to about 1:1. The amount of water is about 1% to several hundred times, preferably about 10% to 10 times, based on the total weight of CF and monomer. The reaction is preferably carried out under an atmosphere of an inert gas, such as nitrogen, at a temperature of about 10-100°C, preferably 20°C.
Performed at ~800°C. The specific reaction temperature here is selected as appropriate depending on the vinyl monomer used, but it is important to carry out the reaction at a temperature that suppresses thermal polymerization to a negligible level, and does not cause extreme thermal polymerization. When carried out at elevated temperatures, the integrity and homogeneity of the resulting composite is inhibited. Reaction time is 30 minutes to approx.
It is 15 hours. The resulting composite can be dried at a temperature ranging from about 10 to 300°C, preferably from about 50 to 200°C. Note that the interaction between the CF surface and the polymer applied by the method of the present invention goes beyond adhesion in a physical sense due to simple adsorption or van der Waals forces, etc. This fact is clear from the fact that even after extraction treatment with a good solvent for vinyl polymers, a large amount of unextracted polymer is observed. Next, the present invention will be explained in more detail with reference to Examples. Example 1, Comparative Examples 1 to 6 A 500 ml four-necked flask equipped with a cooling tube, a nitrogen introduction tube, a stirring rod, and a thermocouple for internal temperature detection was charged with Pitch-based graphite CF (Kureka Tip M manufactured by Kureha Chemical Industry Co., Ltd.).
-201) 38.7g was suspended and dispersed in 280ml of deionized water, and the mixture was purged with nitrogen for 30 minutes. Next, 30.0 g of methyl methacrylate as a vinyl monomer was added under nitrogen flow and vigorous stirring. Next, the temperature of the above reaction solution was raised to 50°C in a hot water bath, and after confirming the uniform dispersion state of the added monomer, commercially available special grade acrylic acid was added as a carboxylic acid monomer.
2.0 g was gradually added, and the polymerization reaction was carried out at the same temperature for 8 hours. After the polymerization was completed, about 2 g was sampled from the reaction solution, and the amount of remaining unreacted monomer was determined by gas chromatography using dioxane as an internal standard reagent to determine the polymerization rate. For comparison, the polymerization behavior in the case of not adding CF, the case of not adding the carboxylic acid monomer, the case of adding propanecarboxylic acid, which is a saturated organic carboxylic acid, and the case of adding sulfite water, was also conducted using the same polymerization operation and An evaluation was conducted after polymerization. The results are shown in Table 1. Note that all parts in the table represent parts by weight.

【table】

[Table] As is clear from Table 1, the system shown in Comparative Example 4 without the addition of a carboxylic acid monomer showed no polymerization activity, and the simple two-component system of a carboxylic acid monomer and a vinyl monomer showed no polymerization activity. While the polymerization activity is extremely low, the method of the present invention in which CF is added as a third component significantly increases the monomer polymerization rate, whereas the conventional polymerization system using sulfite water shown in Comparative Example 6 has a monomer polymerization rate. However, the polymerization conditions such as cullet adhesion and secondary agglomeration performance (granulation properties) are significantly inferior to those of the method of the present invention, indicating that the method of the present invention dramatically improves practicality. Examples 2 to 6, Comparative Examples 7 to 9 All Examples except that methacrylic acid, crotonic acid, tiglic acid, cinnamic acid, and maleic anhydride were used instead of acrylic acid as the carboxylic acid monomer in Example 1. Polymerization was carried out in the same manner as in Example 1, and the monomer polymerization rate was measured and evaluated and compared with Example 1. The results are shown in Table 2.

[Table] As is clear from Table 2, the polymerization activity was extremely high for acrylic acid, methacrylic acid, and crotonic acid, and slightly lower for tiglic acid, cinnamic acid, and maleic anhydride. Approximately 10 g of the polymer composition obtained by the method of Examples 1 to 6 was weighed together with a cylindrical paper, and a 24-hour socks-extraction test was conducted using benzene, which is a good solvent for methyl methacrylate polymer, as an extraction solvent. By this, the polymer extraction rate of the composition was measured.
For comparison, a composition coated with polymethyl methacrylate (Comparative Example 7) prepared by kneading and dispersing Pitch-based CF in a methylene chloride solution of polymethyl methacrylate and then evaporating the solvent and a conventional radical polymerization were prepared. Similar evaluations and studies were conducted on compositions produced using catalysts (Comparative Examples 8 and 9). The results are shown in Table 3, and show that the polymer component in the composition shown in the comparative example was completely extracted in the 24-hour extraction test, whereas the polymer component in the composite obtained by the method of the present invention The extraction rate of the components is small, and most of them are not extracted and are strongly integrated into CF.

[Table] Example 7 The reaction was carried out in the same manner as in Example 1 except that the type of CF was changed, and the results of evaluating the obtained composition are shown in Table 4.

【table】

[Table] As is clear from Table 4, in the case of untreated CF, especially pitch-type CF, when the fiber length reaches approximately 1 mm or more, the CF itself is already flocculent and agglomerated, so it cannot be blended with the resin. Although pressure molding is not possible, when the method of the present invention is applied, a pellet-like composite with good extrusion or injection molding processability can be obtained, making it extremely easy to extrude into a pellet. In addition, in the method of the present invention, CF selectivity regarding polymerization activity was not observed, and the monomer polymerization rate was generally good, and the extraction rate of the polymer component in the component complex was small, and most of it was not extracted. , it can be seen that it is strongly integrated with CF. Example 8 The reaction was carried out in the same manner as in Example 1, except that one type of vinyl monomer or a mixture of two types shown in Table 5 was used instead of methyl methacrylate as the vinyl monomer, and the resulting composition was The evaluation results are shown in Table 5.

[Table] Methyl taacrylate Example 9 In a Henschel mixer for powder kneading,
Add 38.7g of CF (M-201) and 2.0g of acrylic acid to 10
After stirring thoroughly for a minute, the entire amount of the treated fries was suspended and dispersed in 280 ml of deionized water using a reactor set up in the same manner as in Example 1, and the mixture was purged with nitrogen for 30 minutes. Next, 30.0 g of methyl methacrylate as a vinyl monomer was added under nitrogen flow and vigorous stirring. Next, add 50% of the above reaction solution in a hot water bath.
The temperature was raised to 0.degree. C., and the polymerization reaction was carried out at the same temperature for 8 hours. After the polymerization was completed, the same evaluation as in Example 1 revealed that the monomer polymerization rate was 85.6%, and the resulting composite had the CF surface uniformly and firmly fixed by the vinyl monomer polymer. It was a formulated composition. Example 10 The polymer composition obtained according to the present invention was blended with general purpose polymer pellets, and the CF content was 30%.
A composite molded article was prepared using an extruder, and the mechanical and thermal properties of the molded article were evaluated. For comparison, untreated CF (shown as a simple blend in the table) was similarly blended and evaluated. The results are shown in Table 6.

[Table] * Manufactured by Ube Industries, Ltd. As is clear from Table 6, the polymer composition produced by the method of the present invention is a composition with excellent practical properties such as mechanical properties and heat resistance. There is.

Claims (1)

[Claims] 1. The following general formula (In the formula, R ₁ is H, an alkyl group having 1 to 15 carbon atoms,
COOY, halogen atom or phenyl group and its derivatives, R ₂ is H, alkyl group having 1 to 15 carbon atoms, COOZ, halogen atom or phenyl group and derivatives thereof, R ₃ is H, alkyl group having 1 to 15 carbon atoms, A halogen atom or a phenyl group and its derivatives, X, Y, and Z each represent H, NH ₄ or an alkali metal atom. ) or general formula (In the formula, R ₄ and R ₅ are each H, carbon number 1 to 15
represents an alkyl group, a halogen atom or a phenyl group, and derivatives thereof. ) in a heterogeneous polymerization system consisting of an aqueous medium in which carbon fibers are dispersed in the presence of at least one carboxylic acid monomer represented by 1. A method for producing a novel polymer composition, characterized by polymerizing the composition. 2. The method for producing a novel polymer composition according to claim 1, wherein the carboxylic acid monomer is acrylic acid, methacrylic acid, or crotonic acid. 3. The method for producing a novel polymer composition according to claim 1, wherein the vinyl monomer is methyl methacrylate or a monomer mixture containing methyl methacrylate as a main component.