JPH02216280A - Wholly aromatic polyamide fiber - Google Patents

Abstract

PURPOSE:To improve adhesion of the subject fiber to matrix resins without impairing operating efficiency in yarn twisting steps, etc., by applying a specific oiling agent to the surface thereof in which a solid cation exchangeable inorganic compound is adhered. CONSTITUTION:Wholly aromatic polyamide fiber obtained by applying an oiling agent having <=100cSt viscosity at 50 deg.C to the surface thereof in which a solid cation exchangeable inorganic compound is adhered. The above-mentioned oiling agent contains a polyether-based copolymer which is a random or block copolymer of propylene oxide and ethylene oxide having a nitrogen atom- containing compound at the terminals [copolymerization molar ratio of the propylene oxide to the ethylene oxide is (70/30)-(0/100) and the average molecular weight thereof is 400-800].

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to fully aromatic polyamide fibers (hereinafter referred to as aramid fibers) mainly used in fiber reinforced resin materials (FRP).
Regarding.

<Prior art> Aramid fibers have recently become popular as a representative of high-tech fibers.
It is being put into practical use as an advanced composite in fields that require light weight, high strength, and high rigidity by taking advantage of its four characteristics, such as heat resistance, high strength, high modulus, and strong chemical resistance.

However, the adhesiveness between the fibers and the matrix resin is the most important factor in achieving their function as reinforcing fibers. Mainstream matrix resins are epoxy, urethane, and epoxy acrylate.

By the way, in general, aramid fibers exhibit excellent strength in the fiber axis direction, but in the direction perpendicular to the fibers, fibrillation is likely to occur due to the orientation and crystallinity in the fiber axis direction being too high.
Also, the interfacial adhesion with other materials becomes low. Furthermore, the amide group constituting the aramid fiber has extremely weak basicity compared to aliphatic amine due to the influence of the phenyl group adjacent to the amino group, and therefore has weak reactivity with epoxy.

In addition, conventional oils for spinning aramid fibers remain on the fiber surface even after spinning, and when combined with a matrix resin and hydrated to form FRP, they inhibit adhesion at the interface with the matrix resin.

<Objective of the Invention> The present invention not only satisfies the operability in the spinning process or twisting process of aramid fibers, but also improves the adhesion with the matrix resin when composited with the matrix resin to make FRP. The purpose is to fry aramid fibers.

<Structure of the Invention> In other words, the present invention is based on ``random or block polymerization of propylene oxide and ethylene oxide having a nitrogen atom-containing compound at the end on the surface of a wholly aromatic polyamide fiber having a solid cation-exchangeable inorganic compound fixed to the fiber surface. A copolymer with a copolymerization ratio of propylene oxide and ethylene oxide of 70/30 to 0/1oo (molar ratio)
, contains a polyether copolymer having an average molecular weight of 400 to 800, and has a viscosity of 5 (1'C to □C)
Fully aromatic polyamide fibers coated with an oil agent having a temperature below ST.

Aramid fibers include copolyparaphenylene 3゜4゛oxydiphenylene terephthalamide (manufactured by Technora, Teijin), polyparaphenylene terephthalamide (Gebler, manufactured by DuPont), and polymetaphenylene isophthalamide (manufactured by Conex). The aramid fiber of the present invention, such as manufactured by Teijin Corporation, is a fiber to which a solid cation-exchangeable inorganic compound is fixed.

Here, the cation-exchangeable inorganic compound is a compound having the ability to exchange with cations, and specifically includes silica-alumina, silica-magnesia, bentonite, kaolin, Fuller's earth, and acid clay.

These include activated clay, montmorillonite, bitesite, and talc, and these cation-exchangeable inorganic compounds are solid and fixed to the fiber surface. The size of the compound (particles) used is approximately 0.01 to 5 μm. In the present invention, fixation refers to the fact that the compound does not come off at all even when washed with water under severe conditions or immersed in a solvent.

In order to fix the inorganic compound particles to the fiber surface, for example, the inorganic compound particles can be pressed onto the fiber surface in a softened state to bite into the fiber surface, and then the fiber can be solidified. can. That is, a cation-exchangeable inorganic compound is sprayed onto undrawn aramid fibers immediately after spinning, or the aramid fibers are impregnated in a suspension of cation-exchangeable inorganic compound particles suspended in water to coat the fiber surface with inorganic compound particles. A method such as attaching the fiber to the aramid fiber and then subjecting it to hot stretching or heat treatment at a temperature higher than the secondary transition point of the aramid fiber is used.

To describe a specific example of fixing a solid cation-exchangeable inorganic compound (inorganic particles) to the surface of aramid fibers, unstretched aramid laa immediately after spinning is immersed in an aqueous dispersion containing inorganic particles. Inorganic particles are attached to the surface of the aramid yarn, dried, and stretched and heat-treated at least 5 times using a contact heater or a non-contact heater at a temperature above the secondary transition point and below the decomposition point. Fix it so that it looks like a wedge has been driven into the surface,
Aramid m-fibers having a solid cation-exchangeable inorganic compound fixed to the fiber surface are obtained.

Here, the nitrogen atom-containing compound is 21st class, 2nd class or 3rd class.
These include amino compounds containing a class amine group or compounds containing an amide group.

For example, monoethanolamine, jetanolamine, triethanolamine, dimethylaminopropylamine,
Aliphatic amines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and diethylaminoprobylamine.

Also adducts of alkyl epoxies to these.

Cyanoethylated polyamines, aromatic polyamines such as metaphenylene diamine, diaminodiphenylmethane, metaxylene diamine, diaminodiphenylsulfone, alicyclic polyamines such as 3,3'-dimethyl-4,4''diamino-dicyclohexylmethane, Polyamide amines, acetamides, imidazoles such as 2-ethylimidazole, 2-ethyl-4-methylimidazole, etc., which are accompanied by the reaction of dimer acid and aliphatic polyamine, and are not particularly limited as long as they can react with alkylene oxide. Here, the copolymer component of the polyether is composed of ethylene oxide alone or ethylene oxide and propylene oxide, but a nitrogen-containing component such as ethyleneimine may be partially included as a copolymer component.

Here, the nitrogen atom-containing compound used has a large number of functional groups such as amino groups (primary and secondary amines) and hydroxyl groups that react with ethylene oxide and propylene oxide, the greater the intermolecular cohesive force due to hydrogen bonding, and the more The viscosity of the ether polymer increases. As the viscosity of the oil increases, the accumulation of sticky scum is promoted especially in the yarn guiding guide with low roughness, which causes a lot of fuzz during long yarn running. The viscosity is 100 centistokes (CSt) or less. Preferably it is 5-50C3t.

The viscosity was measured using a Canon Fenske at 50°C.

If the viscosity of the oil is less than 5 Cst, smoke will be generated on the hot plates and heated rollers during the spinning process, causing a deterioration of the working environment. If the viscosity exceeds 100 C3t, the coefficient of friction against metal will increase, and the traverse flow of the winding machine will increase. Fixed guides with low surface roughness, such as guides and traveler guides, generate fuzz when they are bent and rubbed.

Therefore, the average molecular weight of the polyether copolymer is 400.
~800 are used. If it is less than 400, smoke will increase on the hot plates and heating rollers in the spinning process, leading to a deterioration of the working environment, and stick-slip will increase due to oil film rupture under high contact pressure, resulting in no fuzz.
When the viscosity of the oil increases, sticky scum accumulates especially on the yarn guiding guide with low roughness, causing frequent fluffing during yarn running for a long time. To reduce the viscosity of oil, 1
) A nitrogen atom-containing compound with a small number of amino groups and hydroxyl groups is used.

2) A low-viscosity component of a polyether copolymer using commonly used alcohols or basic acids as a polymerization initiator is appropriately used in combination.

Polyether copolymer # having a nitrogen atom-containing compound at the end, the mixing ratio of the (nitrogen-containing polyether copolymer) and the low viscosity polyether copolymer is 100/O to 1
At 0/90, the viscosity at 50°C is 100C3t or less, preferably 5 to 50Cst. If it is less than 10/90, the adhesion improvement effect of the nitrogen-containing polyether copolymer will not be exhibited.

In addition, the copolymerization ratio of propylene oxide and ethylene oxide in the nitrogen-containing polyether copolymer is 70/30.
~0/100 (molar ratio), especially 70/30~
A molar ratio of 30/70 is desirable. Molar ratio is 70/30
If the amount exceeds 100%, water solubility decreases and solution stability deteriorates.

The amount of oil applied is 0.5 to 5.0% by weight from the viewpoint of operability from the spinning process to the post-processing process and improvement of adhesion with resin.
The range is preferably from 1.0 to 3.0% by weight, particularly preferably from 1.0 to 3.0% by weight.

If it is less than 0.5% by weight, the lubricity and the cohesiveness of the fiber threads will decrease. If it exceeds 5.0% by weight, product stains will occur due to oil seepage.

<Effect of the invention> The present invention has the following effects.

Oil agents containing nitrogen-containing polyether copolymers (1) decompose on heated rollers or thermal grates after fulfilling their role as oil agents in the yarn spinning process, resulting in problems with adhesion of the yarn after drawing. Only those with a viscosity that does not exceed that level remain.

(2) There are no operational problems such as smoke generation due to heat treatment, fuzz and scum generation due to friction with various guides during the yarn twisting process.

+31 Excellent compatibility and diffusibility with epoxy resin, urethane resin, or epoxy acrylate resin, so there is no interposition at the interface between aramid fiber and 7 trix resin when forming a double self-containment, so the bond between aramid fiber and matrix resin is improved. Demonstrates its action more effectively #: Improves adhesion.

(4) Furthermore, the nitrogen-containing polyether copolymer dispersed into the matrix resin plays a role as a soft segment in the resin structure, suppressing cohesive failure at the adhesive interface and greatly enhancing the functionality of the composite material. improves.

<Example> Hereinafter, the manufacturing method of the present invention will be specifically explained with reference to Examples. In addition, in the examples, evaluations of yarn spinning stability and other properties were carried out by the following methods.

Evaluation method 1. Silk spinning stability (fluff) After 5 hours of continuous spinning at a winding speed of 300 m/min, the surface fluff of the rolled cheese was evaluated.

Evaluation 3. Adhesion (N shear strength: abbreviated as ILSS) 1) Evaluation method for Epicoat 828 n=0.2 molecule 1380 Koshizemate 8001 2. Silk spinning stability (smoking) Five hours after the start of running, the state of smoke on the heated roller set at 180° C. was visually determined.

3) Denako/I, EX-191 glycidyl benzoate The 1 m fibers were immersed in the above epoxy resin and then hardened while being aligned in one direction. The hardened grain is 48% at room temperature.
After being left to stand for a period of time, it was cured by applying pressure at 120°C for 2 hours, and then after another 1 hour at 180°C, a curing treatment was performed.

Test specimens with a length of 20mm, a medium diameter of 6mm, and a thickness of 3011mm were made from the molded product thus obtained (fiber content: 60%), and the span interval was 13m by short beam three-point bending method.
%, crosshead speed? , (at low/min), measure the interlaminar shear strength (ILSS: unit kg/rd).

As shown in Table 1, when the surface-modified aramid fibers of the present invention are used, clearly excellent spinnability and molded product quality can be obtained.

Regarding the oil agent, a 20% concentration water-based emulsion oil agent was applied at the level shown in Table 1 so that the oil agent adhesion i (OPU) was 1.5%. The strength of the obtained fiber is 27g/d
e, elongation was 4.9%.

Examples 1 to 5 Comparative Examples 1 to 4 Aramid consisting of terephthalic acid dichloride, P-phenylene diamine, and 3,4''-diaminodiphenyl ether was spun into a fiber bundle of 1500 denier/1000 filaments, washed repeatedly with water, and then After washing with water, an aqueous bentonite dispersion was applied and stretched at a high temperature of 500° C. The amount of bentonite fixed was 0.42%.

Claims (1)

[Claims] (1) A random or block copolymer of propylene oxide and ethylene oxide, which has a nitrogen atom-containing compound at the end, is applied to the surface of a wholly aromatic polyamide fiber to which a solid cation-exchangeable inorganic compound is fixed. Copolymerization ratio of oxide and ethylene oxide is 70/30 to 0/100 (mole ratio), average molecular weight is 4
A wholly aromatic polyamide fiber containing a polyether copolymer having a molecular weight of 00 to 800 and to which an oil agent having a viscosity at 50° C. of 100 Cst or less is attached.