JPH0354121B2 - - 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 the need for blending or moisture management during iopolymerization. In addition, although two or three unique systems have been reported for non-catalytic polymerization methods that do not use a polymerization initiator, these methods are almost impossible to put into practical use from an industrial standpoint. In view of the above-mentioned current situation, the present inventors have conducted intensive studies and have discovered a method in which a vinyl monomer capable of radical polymerization is brought into contact with CF as a third component in the presence of a specific sulfonic acid monomer or sulfonate monomer. This method significantly increases the polymerization activity of the monomer, strongly unites CF and organic polymer, and provides a novel polymer composition with excellent granulation properties that cannot be obtained by conventional methods. This finding led to the completion of the present invention. 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. Regarding composites with useful inorganic compounds, a wide range of performance improvements such as elastic modulus, heat distortion temperature, and electrical properties have been reported. However, in this case, the properties of the composite materials differ significantly, so the compatibility,
The essential drawback is that it has poor interfacial affinity such as adhesion, and cannot exhibit sufficient composite effects, and in particular, powdered inorganic fillers inevitably suffer from a decline in some of the resin's inherent physical properties, such as toughness. have. 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 by 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 research into improving this point, the present inventors discovered a practical method for producing a composite in which vinyl polymer is firmly integrated with various powdered inorganic compounds in the presence of a specific sulfonic acid monomer. First, a patent application No. 1983-937 was filed. Subsequently, as a result of further investigation, it was found that CF has particularly high polymerization activity and excellent interfacial cohesion as an inorganic compound, and that it is particularly noticeable not only in powdered fine fibers but also in relatively long fibers. It was discovered that it exhibits granulation properties, and the present invention was completed. That is, the present invention provides the following general formula (In the formula, R ₁ is H, an alkyl group having 1 to 20 carbon atoms,
Phenyl group and its derivatives or halogen atom, X is CONH,

[Formula] COO (CH ₂ ) _n or (CH ₂ ) _o , R ₂ and R ₃ are each H or an alkyl group having 1 to 15 carbon atoms, R ₄
is an alkylene group having 1 to 15 carbon atoms, m is an integer of 1 to 20, n is an integer of 0 to 20, and Y is H, NH ₄ or an alkali metal atom). CF and an organic polymer are strongly integrated by polymerizing at least one radically polymerizable vinyl monomer in the presence of CF and in a polymerization system in which CF is dispersed. A method for producing a novel polymer composition is provided. 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, a feature of the present invention is 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 to fine powder CF, it can also be applied 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 can be said to be a great practical value of the present invention. To give an example of an embodiment when 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 sulfonic acid monomer or sulfonate is added. By adding and stirring the acid salt monomer, an aqueous heterogeneous polymerization reaction is caused, and the CF surface is uniformly and firmly covered with the vinyl monomer polymer at a high polymerization rate over a predetermined polymerization time. It can be fixed. At this time, it is an essential condition that the three components mentioned above are brought into contact with each other in coexistence.
They do not necessarily need to be brought into contact at the same time. That is,
For example, using CF pretreated with sulfonic acid or sulfonate monomers
By the method of the present invention, similar polymer compositions can be obtained without adding new sulfonic acid monomers or sulfonate monomers during the polymerization of the monomers. 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 the specific sulfonic acid monomer or sulfonate monomer represented by the above general formula [], a clean polymerization form with almost no cullet formation is obtained, and more surprisingly,
Because the resulting polymer composition has excellent granulation properties,
This provides a method for obtaining a product with extremely easy post-processes such as washing and recovery. The specific sulfonic acid monomer or sulfonate monomer used in the present invention has a sulfonic acid group as an active side that brings about polymerization activity, and an active side that exhibits strong union between the produced polymer and CF. The presence of a double bond is essential, and compounds having the structure represented by the above general formula [] that have both of these two types of functional groups can be applied, and a specific example thereof is 2-acrylamide-2-methylpropane. Sulfonic acid (hereinafter referred to as
AMPS), sodium 2-methacrylethanesulfonate (hereinafter abbreviated as SEM・Na), 3
-Sodium methacrylicpropanesulfonate (hereinafter abbreviated as SPS), sodium 2-propenesulfonate (hereinafter abbreviated as NaAS), 2-methyl-
Sodium 2-propenesulfonate (hereinafter referred to as
(Abbreviated as NaMS), etc., but especially AMPS containing amide bonds, SEM and
Na, SPS, and the like are preferred because they exhibit remarkable granulation properties and have high polymerization activity. The CF used in the present invention includes high-strength or high-elasticity CF made of polyacrylonitrile or its copolymer, petroleum high-temperature cracking pitch, coal tar pitch, and coal depolymerized products as raw materials.
Examples include CF and CF produced by vapor phase growth, 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. Among them, 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. Especially in the case of pitch-type CF, about 1
When the fiber length exceeds mm, 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, a pellet-like composite with good extrusion or injection molding processability is obtained. Therefore, in addition to the interfacial effect, the present invention is extremely unique and has high practical value as a method for controlling the shape of composites. Regarding roving-like long fibers,
The present invention can be applied by static treatment or gentle stirring conditions, 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 invention, the concentration of sulfonic acid monomer or sulfonate monomer is about 0.05 to 100% by weight based on the total weight of CF and monomer, preferably
It is used in amounts of 0.1 to 50% by weight, particularly preferably 0.5 to 30% by weight. In most cases, it is preferred to increase the amount of sulfonic acid or sulfonate monomer as the monomer component increases. The weight ratio of monomer or monomer mixture to CF used can vary within a wide range and is from about 500:1 to 1:5, preferably from 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 at a temperature of about 10-100°C, preferably 20-80°C, under an atmosphere of an inert gas, such as nitrogen. The specific reaction temperature here is selected as appropriate depending on the vinyl monomer used, but it is important to conduct the reaction at a temperature that suppresses thermal polymerization to a negligible degree, and not at a high temperature that would cause extremely thermal polymerization. When carried out, the integrity and homogeneity of the resulting complex is inhibited. reaction time is 30
minutes to about 15 hours. The generated complexes are approximately 10-300
℃, preferably in the temperature range of about 50 to 200℃. 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, and this fact This is clear from the fact that a large amount of unextracted polymer is observed even after extraction treatment with a good solvent for vinyl polymer. 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 detecting internal temperature was charged with a pitch-based graphite CF (Kureka Tippu manufactured by Kureha Chemical Industry Co., Ltd.).
38.7 g of M201) was suspended and dispersed in 270 ml 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 a uniform dispersion state of the added monomer was confirmed. The mixture 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 after the reaction, 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, we also looked at the polymerization behavior when no CF was added, when no sulfonic acid monomer or sulfonate monomer was added, when ethanesulfonic acid, which is a saturated organic sulfonic acid, was added, and when sulfite water was added. Similar polymerization operations and post-polymerization evaluations were conducted. The results are shown in Table 1. All parts are by weight.

【table】

[Table] As is clear from Table 1, the system shown in Comparative Example 4 in which the sulfonic acid monomer or sulfonate monomer was not added showed no polymerization activity, and the sulfonic acid monomer or sulfonate monomer and vinyl monomer In contrast, the polymerization activity is extremely low in a simple two-component system in which CF is added as a third component, whereas the monomer polymerization rate is significantly increased by the method of the present invention in which CF is added as a third component. Although the polymerization system has a high monomer polymerization rate, the polymerization conditions such as cullet adhesion and secondary aggregation performance are significantly inferior to the method of the present invention, and it is concluded that the method of the present invention dramatically improves practicality. It shows. Examples 2 to 5, Comparative Examples 7 to 9 In Example 1, instead of SEM Na as the sulfonic acid monomer or sulfonate monomer
Polymerization was carried out in the same manner as in Example 1 except that SPS, AMPS, NaAS, and NaMS were used, 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 is SEM/
Na, SPS, AMPS are extremely high, NaAS,
NaMS showed a slightly low level. Approximately 10 g of the polymer composition obtained by the method of Examples 1 to 5 was weighed together with a cylindrical paper, and a 24-hour Soxhlet extraction test was conducted using benzene, which is a good solvent for methyl methacrylate polymer, as an extraction solvent. The polymer extraction rate of the composition was measured. For comparison, a composition coated with polymethyl methacrylate produced by kneading and dispersing an inorganic powder (Pitzi-based CF) in a methylene chloride solution of polymethyl methacrylate and then evaporating the solvent was prepared (Comparative Example 7). ) and a conventional radical polymerization catalyst, the compositions produced (Comparative Examples 8 and 9) were also evaluated and studied in the same manner. 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 components is small, and most of them are not extracted.
It is strongly integrated into CF.

【table】

[Table] Example 6 The reaction was carried out in the same manner as in Example 1 except that the type of CF was changed, and the resulting composition was evaluated.
The results 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,
Since CF itself is already flocculent and agglomerated, it cannot be blended with resin and extruded.
When the method of the present invention is applied, a pellet-like composite with good extrusion or injection molding processability is obtained, so blend extrusion becomes extremely easy. In addition, in the method of the present invention, CF selectivity regarding polymerization activity is not observed, and the monomer polymerization rate is generally good, and
It can be seen that the extraction rate of the polymer component in the generated complex is small, most of it is not extracted, and it is strongly integrated with CF. Example 7 As the vinyl monomer, one or two vinyl monomers shown in Table 5 were used instead of methyl methacrylate.
The reaction was carried out in the same manner as in Example 1 except that a mixture of seeds was used, and the results of evaluation of the obtained composition are shown in Table 5.

[Table] Example 8 In a Henschel mixer for powder kneading,
Add 38.7g of CF (M-201) and 6.5g of SEM Na,
After stirring thoroughly for 10 minutes, the entire amount of the treated filler 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, the temperature of the reaction solution was raised to 50° C. in a hot water bath, and a 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 80.5%, and the CF surface of the resulting composite was uniformly and firmly fixed with the vinyl monomer polymer. The composition was Example 9 The polymer composition obtained according to the present invention was blended with general-purpose polymer pellets, the CF content was adjusted to 30%, a composite molded article was created using an extruder, and the molded article was machined. The physical and thermal properties 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] As is clear from Table 6, the polymer composition produced by the method of the present invention is a composition that is excellent in practicality such as mechanical properties and heat resistance.

Claims (1)

[Claims] 1. The following general formula (In the formula, R ₁ is H, an alkyl group having 1 to 20 carbon atoms,
Phenyl _{group and its derivatives} or _{halogen atom} ; _Four
is an alkylene group having 1 to 15 carbon atoms, m is an integer of 1 to 20, n is an integer of 0 to 20, and Y is H, NH ₄ or an alkali metal atom). 1. A method for producing a novel polymer composition, which comprises polymerizing at least one radically polymerizable vinyl monomer in the presence of carbon fibers in a polymerization system in which carbon fibers are dispersed. 2. Claims characterized in that the sulfonic acid monomer or sulfonate monomer is 2-acrylamido-2-methylpropanesulfonic acid, sodium 2-methacrylethanesulfonate, or sodium 3-methacrylpropanesulfonate A method for producing the novel polymer composition according to item 1. 3. The method for producing a novel polymer composition according to claim 1 or 2, wherein the main component of the vinyl monomer is methyl methacrylate.