JP2641271B2 - Surface-modified wholly aromatic polyamide fiber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wholly aromatic polyamide fiber having improved surface strength. More specifically, in applications such as cords and ropes used by twisting fiber bundles, their wear resistance is excellent,
Further, the present invention provides a wholly aromatic polyamide fiber having excellent twist strength retention.

<Prior art> In recent years, wholly aromatic polyamide fibers are among organic fibers, and especially, new applications in various fields by utilizing their excellent properties such as high strength, high modulus, high heat resistance, and high chemical resistance. Has been put to practical use.

However, such fibers have high molecular orientation and high crystallinity, so the mechanical properties in the fiber axis direction exhibit an outstanding function, but on the other hand, they are surprisingly brittle in the direction perpendicular to the fiber axis. The fact is also clear.

In particular, fibrillation easily occurs due to rubbing between fibers or rubbing with other objects, and the fibers are easily abraded. Therefore, the strength which was superior after a process such as twisting is greatly reduced, so-called strength retention. Shows the disadvantage of low rates.

In order to solve these problems, attempts have been made to improve by physical methods such as twisting method and twisting conditions, but none of the proposals regarding the relationship between the fiber surface properties is sufficient. Is the current situation.

As a method for improving the surface properties of fibers, a method of protecting the fiber surface by, for example, applying a solid wax component to the fiber surface or coating the fiber surface with a resin such as a fluororesin is used. However, according to these methods, in the post-processing step, the fixed solid components fall off and accumulate on the yarn conductor, which causes various troubles. In the method, the processing speed is limited, which is not only unfavorable for commercial production, but also because the fibers are resin-coated in a bundled form, the movement of the single fibers is restricted, and the yarn as a whole becomes stiff, and thus the high strength is obtained. There is a disadvantage that the retention cannot be improved.

<Object of the Invention> The present invention has been studied as to how to greatly improve the properties of the fiber surface while maintaining the excellent properties of the conventional aramid fiber, and as a result, it has been found that the surface of the fiber is modified with a specific compound. The present inventors have found a serious fact that the abrasion resistance between fibers can be remarkably increased as compared with the related art, and arrived at the present invention.

That is, an object of the present invention is to provide a fiber having a surface excellent in abrasion resistance in a use such as a cord or a rope which is subjected to a twisting process, and therefore, a surface having a high strength retention after twisting. It is intended to provide a modified wholly aromatic polyamide fiber.

<Constitution of the Invention> That is, the present invention provides a method of forming a liquid at a temperature of 15 ° C. or more on the surface of a wholly aromatic polyamide fiber having a solid cation-exchangeable and non-ion-adsorbing inorganic compound fixed to the fiber surface. Indicating molecular weight 10,000
An aliphatic monovalent ester-based lubricant having a coating composed of the above polyoxyalkylene-containing polyether compound and having a molecular weight of 900 or less, which is incompatible with the polyether compound and water-insoluble, on the coating. A surface-modified wholly aromatic polyamide fiber having a layer. "

Here, the cation-exchangeable and non-ion-adsorbing inorganic compound is a compound having an ability to exchange cations and an ability to adsorb non-ions, specifically, silica-alumina, silica-magnesia, bentonite, Kaolin, Fuller's earth, acid clay, activated clay, montmorillonite, baitsite, talc, etc. These cation exchangeable and non-ion-adsorbing inorganic compounds are fixed to the fiber surface in a solid state. The size of the compound (particle) is approximately 0.
Those having a size of about 01 to 5 μm are used. In the present invention, the term "fixation" means that the substance is not detached at all by a washing treatment in a violent state or by immersion in a solvent.

The inorganic compound particles can be fixed to the fiber surface by, for example, pressing the inorganic compound particles against the fiber surface in a state where the fiber surface is softened, biting the fiber surface, and then solidifying the fiber. That is, the cation-exchange and non-ion-adsorbable inorganic compound is sprayed on the wholly aromatic polyamide fiber immediately after spinning, or the fragrance is completely suspended in a suspension of the cation-exchange and non-ion-adsorbable inorganic compound particles in water. The aromatic polyamide fiber is immersed to adhere the inorganic compound particles to the fiber surface, and then subjected to heat drawing or heat treatment at a temperature not lower than the secondary transition point of the wholly aromatic polyamide fiber.

The wholly aromatic polyamide fiber is, for example, paraphenylene terephthalamide composed of a predetermined aromatic dicarboxylic acid and an aromatic diamine or a copolymer thereof, but is not particularly limited.

The polyoxyalkylene-containing polyether compound refers to one of polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, or a copolymer thereof. Those preferably used here are those obtained by copolymerizing propylene glycol and ethylene glycol at an arbitrary molar ratio with a lower alcohol such as butanol or ethylene glycol as a starting material to obtain a high molecular weight.

Here, in particular, the molecular weight is 10,000 or more and 15 ° C
It is liquid at the above temperature.

If the molecular weight does not exceed 10,000, a material having a high abrasion resistance on the surface of the intended fiber cannot be obtained, and
If the liquid is not liquid at a temperature of 15 ° C. or more, not only is it difficult to handle the fiber when applied to the fiber, but also during the post-processing of the fiber, solid matter called scum causes accumulation of stains on the yarn conductor and the like, which is not preferable.

Such a high molecular weight ether compound is highly viscous due to its molecular structure, has a strong liquid film, and enhances lubricity under extreme pressure. Therefore, even if a high contact pressure is applied between the fibers due to the action of the twisted yarn or the like, there is a degree of freedom between the fibers. That is, the inter-fiber frictional force is reduced, the abrasion resistance strength of the fiber surface is increased, and the strength reduction due to twisting is suppressed.

However, on the other hand, due to the high viscosity, the fiber having the generated film has a high running friction when running on the yarn guides, and a single color is taken by the yarn guides, causing fluffing or the like. However, since various troubles such as generation of guide dirt as an adhesive scum occur, it cannot be used alone at all. Therefore, in the case of the present invention, it is necessary to use a low friction lubricant in combination.

When two kinds of compounds are used in combination, they are usually compatible with each other, unless they have an affinity for each other, so that the effect of using a low friction lubricant is not exhibited. Therefore, the lubricant used in the present invention needs to be incompatible with the polyoxyalkylene-containing polyether compound.

Further, in the case of the present invention, since the fiber surface is previously modified to be cation-exchangeable and non-ion-adsorbing, the high-molecular-weight polyoxyalkylene-containing aliphatic polyether-based compound is preferentially adsorbed on the fiber surface, Therefore, a low-friction lubricant is formed on the coating, thereby achieving the purpose of reducing running friction.

Thus, it is an important point of the present invention that the extreme pressure lubricant composed of the polyether compound containing a high molecular weight polyoxyalkylene and the low friction lubricant have a two-layer structure on the fiber. is there.

The lubricant incompatible with the polyoxyalkylene-containing polyether compound used in the present invention is an aliphatic monovalent ester lubricant having a molecular weight of 900 or less.

The aliphatic monoester lubricant is an ester of a monohydric alcohol and a monobasic acid, such as octyl palmitate, oleyl oleate, and isostearyl oleate.

In this case, if the molecular weight exceeds 900, the viscosity is high, and therefore it cannot be used as a low friction lubricant. Also,
Non-aliphatic compounds, for example, compounds having an aromatic ring also have high friction and cannot be used.

The treatment of the fiber with the high molecular weight polyoxyalkylene-containing polyether compound (A) and the aliphatic monohydric ester lubricant (B) having a molecular weight of 900 or less is as described above.
After fixing a cation-exchangeable and non-ion-adsorbing inorganic compound on the fiber in advance, first apply the compound (A) to form a coating of the compound on the fiber surface, and then apply a lubricant The compound (A) and the lubricant (B) may be simultaneously applied. Compound (A) may be added at the same time for the reasons described above.
Is adsorbed on the fiber side, and as a result, the same effect as in the case where the application treatment is performed twice is obtained.

In addition, these treatments may be used as an aqueous fiber treatment liquid containing such an agent in water, or as a non-aqueous fiber treatment liquid containing an agent in a solvent substantially free of water. The treatment may be carried out, and any of known means such as an oiling roller, a measuring oiling nozzle, and a spray may be used as a means for further applying treatment.

Further, as the treatment liquid, other compounds such as an antistatic agent may be mixed with the fiber treatment agent as needed in addition to the compound (A) and the lubricant (B) of the present invention.

The amount applied as a fiber treatment agent is 0.1% based on the fiber weight.
~ 5% by weight is preferred. The application amount is preferably in the range of about 0.1 to 2% by weight of each of the compound (A) and the lubricant (B) based on the weight of the fiber.

<Effects of the Invention> The present invention relates to a wholly aromatic polyamide which does not increase running friction when running on a yarn guide in a fiber processing step, and thus does not cause fluff and yarn breakage during running. It is an object of the present invention to provide a wholly aromatic polyamide fiber having a high abrasion resistance on the surface while taking advantage of the inherent properties of the fiber such as high strength and high modulus.

<Example> Hereinafter, the present invention will be described specifically with reference to examples.

In addition, the characteristic value used for evaluation in this invention was measured according to the following method.

(1) Abrasion resistance of fiber surface As shown in Fig. 1, disks 1,2 rotating both ends of fiber Y of 1500 denier 1000 filaments at constant rotation (500 rpm)
Then, the fiber is twisted through pulleys 3 and 4 at point A so that the number of twists is 2 turns, and crossed, and the fiber is hung on pulley 5 with a load 6 of 500 g.

The intersection of the fibers at point A was 40 °, and the reciprocating stroke length of the fibers was 50 mm.

In this manner, the fibers were repeatedly rubbed with each other, and the time until rubbing and cutting was expressed in seconds, and evaluated as abrasion resistance.

(2) unwound fiber Y from yarn package 1 as shown in the running friction coefficient Figure 2 further adjusts the tension T ₁ to 20g in S-shaped tension compensator 3 via Itoshirube guide 2, the surface roughness The cylindrical friction body 4 of 60φ of 11S is contacted at a contact angle of 180 ° and its output side tension (T ₂ )
After the measurement, the yarn bundle was run through the rotating roller 5 having a surface speed of 300 m / min. The friction coefficient at this time is μ = (1 /
π) In (T ₂ / T ₂ ).

(3) Fiber strength retention rate (i) Using an Instron tensile tester, measure the tensile cutting strength of a fiber sample having an initial length of 25 cm in an atmosphere of 20 ° C. and 65% RH at a tensile speed of 10 cm / min. From this, the fiber strength (g / de) was determined.

(Ii) Using an Instron tensile tester, a twisted and twisted Nippon twisted cord of 40 turns per 10 cm was measured under the same measurement conditions as in (i) to determine the strength (g / de) of the cord.

The strength retention was determined from the ratio of the strength of these cords to the strength of the fiber.

(4) Comprehensive Judgment The results evaluated by the above measurement methods were comprehensively evaluated, and good to bad were indicated by 〜 to ×.

Examples 1-3, Comparative Examples 1-6 Para-wholly aromatic polyamide consisting of terephthalic acid dichloride and paraphenylenediamine and 3,4'-diaminodiphenylate was spun out, washed with water repeatedly, and then attached with a bentonite aqueous dispersion after washing with water. At the very least, hot drawing was performed at 500 ° C. to obtain a cation-exchangeable and non-ion-adsorbable wholly aromatic polyamide fiber (1,500 denier, 1000 filaments) having 0.42% of non-falling bentonite on the fiber surface.

Immediately after the stretching of the wholly aromatic polyamide fiber, a 15% aqueous emulsion having the composition shown in Table 1 was applied so that the solid content was 3.5% based on the weight of the fiber as an adhesion amount, dried, and wound up. .

Table 2 shows the results of the evaluation of the obtained fibers by the above evaluation method.

Comparative Example 6 in Table 2 shows the results of comparative evaluation of fibers to which no cation-exchangeable and non-ion-adsorbing inorganic compound was applied as the wholly aromatic polyamide fiber and to which the oil agent of Example 1 was applied. Was.

From these results, it is clear that the present invention shows a remarkable effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an apparatus for measuring abrasion resistance of a fiber surface.
1, 2 are disks, 3, 4, and 5 are pulleys, 6 is a load, A is a crossing point of fibers, and Y is a fiber. FIG. 2 is a schematic view of an apparatus for measuring a running friction coefficient of a fiber. 1
Is a package, 2 is a yarn guide, 3 is a tension compensator, 4 is a cylindrical friction body, 5 is a rotating roller, and T ₁ and T ₂ are tension measuring devices.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location // D06M 101: 36

Claims (1)

(57) [Claims] The present invention relates to polyaromatic polyamide fibers comprising a solid cation-converting and non-ion-adsorbing inorganic compound fixed to the surface of a fiber. It has a coating made of an alkylene-containing polyether compound, and has a layer of an aliphatic monoester lubricant having an incompatibility with the polyether compound and a molecular weight of 900 or less on the coating. Surface-modified wholly aromatic polyamide fibers.