JPH054348B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a binding agent for satisfactorily binding glass fibers, carbon fibers, ceramic fibers, etc. with water-soluble polyamide. [Prior Art] In recent years, reinforced plastics made of inorganic fibers and various polymers have been used for automobile parts, aircraft parts, precision machinery parts, household goods such as bathtubs and septic tanks, boats,
It is used in large quantities for a variety of purposes in a wide range of fields, including sports equipment such as golf and skiing, and hard hats. Inorganic fibers will continue to be widely used as reinforcing materials for general synthetic resins, metals, ceramics, etc., but when these inorganic fibers are used as reinforcing materials, they must be converged with a converging agent, It is cut into short pieces and kneaded with synthetic resin, etc. to obtain a composite. [Problems to be solved by the invention] The problems that have arisen in the series of processes up to now are: (1) The binding agent is applied to the fiber bundles, but in the case of using an organic solvent, the environmental sanitation of the workplace, Particular attention must be paid to the problem of external pollution, and from the safety point of view, when flammable and explosive solvents are used, all process equipment must be completely explosion-proof, which increases equipment costs. (2) It is necessary to improve the convergence performance of the convergence agent. (3) If the compatibility with the matrix material is poor, a strong matrix material cannot be obtained. Various sizing agents have been studied to solve the above problems, but water-soluble sizing agents are the best in terms of environmental health, pollution, and safety, but they are not compatible with the matrix material. There were many sizing agents that had advantages and disadvantages, such as not being good and not producing a composite with good strength. [Means for Solving the Problems] The present inventors have carried out intensive research with the aim of solving these problems, and have found that a binding agent for inorganic fibers that has good impregnating properties and binding properties for matrix materials It has been found that a water-soluble polyamide resin having a specific structure is the most suitable. That is, the present invention has a tertiary amino group and/or
Alternatively, the present invention provides a water-soluble sizing agent for inorganic fibers containing as a main component a water-soluble polyamide obtained by polycondensing a diamine having an oxyethylene group and a dicarboxylic acid. This water-soluble polyamide is a polyamide resin obtained by polycondensing a diamine having a tertiary amino group and/or an oxyethylene group in its main chain with a dicarboxylic acid. Monomers containing a tertiary amino group in the main chain, such as γ-aminopropyl)piperazine and N-(β-aminoethyl)piperazine, and alkyldiamines containing an oxyethylene group in the main chain, such as oxyethylenealkylamine, are useful. . In addition, examples of dicarboxylic acids include adipic acid and sebacic acid. The water-soluble polyamide of the present invention may be a copolymer. Examples of copolymerization components include α-pyrrolidone, α-piperidone, ε-caprolactam,
α-Methyl-ε-caprolactam, ε-Methyl-
Lactams such as ε-caprolactam and ε-laurolactam can be mentioned, and binary copolymerization or multi-component copolymerization is also possible, but the copolymerization ratio is determined within a range that does not interfere with the physical property of water solubility. Preferably, the proportion of the copolymer component having a lactam ring must be within 30% by weight, otherwise the polymer will not be completely soluble in water. However, even for poorly water-soluble polymers with a copolymerization component ratio outside the above range, the solubility increases when the solution is made acidic using an organic or inorganic acid.
It becomes water soluble and can be used. Examples of organic acids include acetic acid, chloroacetic acid, propionic acid, maleic acid, oxalic acid, and fluoroacetic acid, and examples of inorganic acids include common mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid. . The water-soluble polyamide thus obtained is dissolved in water or an acidic aqueous solution to a concentration of 0.1% by weight or more, preferably 1% to 20% by weight, and used as a sizing agent for inorganic fibers. The binding agent is applied to the inorganic fibers by a conventional method such as dipping or spraying, and several hundred to tens of thousands of filaments are bundled. The amount of this sizing agent attached to the inorganic fibers depends on the thickness of the filament, but the polymer solid content is 1 to 20%.
% by weight, preferably 3-10% by weight. In this case, if the amount of adhesion is too small or too large, workability in post-processing will be poor, leading to problems such as winding onto a bobbin and cutting. In particular, if the amount is too small, the filament will come apart and fuzz will occur. If there is too much, the filament will lose its flexibility and become too hard, making it difficult to wind it onto the bobbin smoothly. The inorganic fibers that have been given a sizing agent in this way are subjected to water removal and heat treatment in a dryer, but the conditions for this heat treatment are also important for the workability of post-processing after winding the bobbin. It has to do with the quality of sexuality. That is, after the sizing agent of the present invention is applied to inorganic fibers, moisture is removed in a dryer using hot air at room temperature to 100°C, and then heat treatment is performed under a temperature range of 150 to 300°C. Preferably, it is carried out under a temperature condition of 200 to 280°C. This heat treatment temperature is the temperature at which the water-soluble polyamide self-crosslinks due to oxygen in the air, and is the temperature at which it loses its water-soluble physical properties. This treatment makes the water-soluble polymer insoluble and loses its hygroscopicity, which eliminates the stickiness of the strands containing the filaments, which not only improves the workability of post-processing, but also improves adhesion to the matrix material, making it easier to handle. We can provide inorganic fibers. This sizing agent using water-soluble polyamide resin has excellent affinity with various matrix materials and significantly improves the properties of composites, but it is especially suitable for polyamide resins, polyimide resins, polyamide-imide resins, and polyetheramide-imide resins. It has an excellent effect of improving adhesion in resins. Such polyamide resins include nylon-6, nylon-66, nylon 610, nylon
There are aromatic polyamides made by reacting 612 and P-phenylenediamine with phthalic acid chloride. Examples of polyimide resins include resins obtained by a cyclization reaction of trimellitic anhydride and hexamethylene diamine. The polyamide-imide resin is a copolymer of the above polyamide component and polyimide component. Further, the polyetheramide-imide resin is a resin obtained by copolymerizing a polyamide-imide resin component with a component containing an ether bonding group such as polyethylene glycol. The method of forming a composite material from these matrix materials and inorganic fibers is carried out by a general injection molding method or a monomer casting method, in which a filament bundle of inorganic fibers coated with a water-soluble sizing agent is cut into one bundle with a cutter. A composite product is obtained by cutting the material into pieces of about 10 mm, mixing them thoroughly in a blender with chips of matrix material such as the polyamide mentioned above, and then injection molding, or by putting the monomer and catalyst together in a mold and molding. [Effects] The water-soluble sizing agent of the present invention exhibits the following effects. (1) Inorganic fibers have excellent convergence. (2) It is possible to improve the adhesion between the converged inorganic fibers and the matrix material, resulting in a composite with excellent strength. (3) After winding up the inorganic fiber bundle to which the sizing agent of the present invention has been applied onto a paper tube, the fiber bundle has excellent unwinding properties when the fiber bundle is unwound from the paper tube. [Example 1] Put 13.8 kg of water and 7.33 kg of adipic acid (abbreviated as AA) into a pot equipped with a 40-mm stirrer, dissolve, and add N-(β-aminoethyl)piperazine (abbreviated as AEP) little by little. When 6.47 kg was added, the pH reached 7.3, so the salt reaction was terminated and 1.53 kg of ε-caprolactam (abbreviated as LC), a copolymer component, was added. After stirring and dissolving and replacing the air in the pot with nitrogen gas, the temperature was raised to 230°C over 4 hours while removing water, and then 98% sulfuric acid was added for 1.5 hours to complete the polycondensation reaction. A polymer with a viscosity of 1.7-2.4 was obtained. Polymers of other compositions were similarly polymerized. Also, N,N'-bis(γ-aminopropyl)
Tables 1 to 3 show the results of similar polymerizations using piperazine (abbreviated as BAPP) and α,ε-bis(aminopropioxy)polyethylene glycol (abbreviated as PGD) in place of AEP.

【table】

【table】

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[Example 2]

5% by weight of the water-soluble sizing agent obtained in Example 1
It was dissolved in water and used as a binding agent for glass fibers. Glass fibers consisting of 10μ x 1000 filaments are immersed in an aqueous solution, excess aqueous solution is removed with a roller, and heat treated for 3 minutes in a hot air dryer at 240-250°C to obtain glass fibers with a binding agent adhesion of 2-3%. I got it. This fiber was cut into a length of 3 mm and kneaded with nylon 6 pellets to obtain a molded product containing 15% glass fiber. In order to compare the physical properties of the composite of this molded product, the same tests as above were conducted using an acrylamide polymer as a comparison product. The results are shown in Table 4.

[Example 3]

To the 5% aqueous solution of the water-soluble sizing agent obtained in Example 1,
A glass fiber consisting of 10μ x 1000 filaments is immersed, excess aqueous solution is removed using a roller, heat treated in a hot air dryer at 240-250℃ for 3 minutes, and tension is applied to the bobbin.
After winding at 300 kg, the strand was left to stand for 10 days at 25°C and 65% RH, and then the strand was unwound to examine its unwinding properties. Polyacrylamide was also tested in the same manner as a comparative product. The results are shown in Table 5.

【table】

[Example 4]

A water-soluble AEP-90 sizing agent was dissolved in water to a concentration of 5% and applied at 3% to a glass fiber consisting of a 10μ x 1000 filament, and heat treated for 4 minutes at different temperatures to create tension.
After winding on a bobbin with 300Kg, 25℃ 65%RH
After being left for 10 days under these conditions, the strands were unrolled and the unwinding properties were examined. The results are shown in Table 6.

【table】

Claims (1)

[Claims] 1. A water-soluble sizing agent for inorganic fibers containing as a main component a water-soluble polyamide obtained by polycondensing a diamine having a tertiary amino group and/or oxyethylene group in its main chain with a dicarboxylic acid.