JPH02216276A - Wholly aromatic polyamide fiber having modified surface - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having the surface with high abrasion resistance thereof without impairing characteristics of wholly aromatic polyamide fiber having the surface thereof with a specified inorganic compound adhered thereto by forming a film of a specific aliphatic polyester-based compound on the surface of the above-mentioned fiber and then a lubricant layer thereon. CONSTITUTION:Wholly aromatic polyamide fiber, obtained by adhering a solid cation exchangeable and ion nonadsorbing inorganic compound, e.g. silica- alumina, is adhered to the surface of wholly aromatic polyamide fiber, forming a film consisting of an aliphatic polyester-based compound which is liquid at >=15 deg.C and contains a polyoxyalkylene having >=3000 molecular weight thereon and then forming a layer consisting of an aliphatic lubricant (e.g. octyl palmitate) which is incompatible with the aforementioned polyester and has <=900 molecular weight and/or a silicone-based lubricant (preferred example; dimethylsilicone) thereon, having the modified surface and improved in abrasion resistance of the fiber surface. An ester of a polyalkylene glycol with a monobasic or dibasic acid, such as capric or adipic acid, is preferred as the polyester compound.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a wholly aromatic polyamide fiber with improved surface strength. More specifically, in applications such as cords and ropes that are made by twisting fiber bundles, it has excellent abrasion resistance and W.
The present invention provides a wholly aromatic polyamide KM with excellent yarn tenacity retention.

<Prior art> In recent years, fully aromatic polyamide limb has been used as a new material in various fields, taking advantage of its excellent properties such as high strength, high modulus, high heat resistance, and high chemical resistance. It has been put into practical use.

However, because such fibers have high molecular orientation and crystallinity, they exhibit excellent mechanical properties in the fiber axis direction, but on the other hand, I! It has also become clear that it is surprisingly fragile in the direction perpendicular to the i-line axis.

In particular, fibrillation easily occurs due to friction between fibers or friction between fibers and other objects, and the fibers are easily worn out. Therefore, when processes such as twisting are performed, the strength that was previously dominant is greatly reduced, and the so-called strength retention is reduced. It shows the drawback of low rate.

In order to solve these problems, attempts have been made to improve them through physical methods such as twisting methods and twisting conditions, but what has been proposed regarding the relationship with fiber surface properties is
The current situation is that there is still not enough.

Methods that have been used to date to improve the surface properties of fibers include methods of protecting the fiber surface by applying a solid wax component to the fiber surface, or coating the fiber surface with fluororesin, etc. However, according to these methods, various troubles occur due to the fixed solid components falling off and depositing on the thread guide in the post-processing process, and on the other hand, methods using resin coating cause problems. Not only is the processing speed limited, which is unfavorable for commercial production, but the TL miscellaneous particles are coated with resin in a concentrated form, which restricts the movement of single fibers and makes the yarn stiff as a whole, resulting in strong retention. It has the disadvantage that it does not improve the efficiency.

<Purpose of the Invention> The present invention was developed as a result of intensive research into a method for greatly improving the surface properties of fibers while maintaining the excellent properties of conventional aramid 1ilffl. The inventors have discovered the important fact that the abrasion resistance strength between fibers can be significantly increased more than ever before, and have arrived at the present invention.

That is, the object of the present invention is to provide a fiber having a surface with extremely excellent abrasion resistance for applications such as cords and lobes that are twisted and used, and thus having a surface with high strength retention after twisting. The present invention aims to provide a modified wholly aromatic polyamide fiber.

<Structure of the Invention> That is, the present invention provides a fully aromatic polyamide fiber having a solid cation-exchanging and nonion-adsorbing inorganic compound fixed to the fiber surface, which exhibits a liquid state at a temperature of 15°C or higher. Molecular weight 300
It has a coating made of an aliphatic polyester compound containing 0 or more polyoxyalkylene, and on the coating is an aliphatic lubricant and/or a silicone-based lubricant that is incompatible with the polyester compound and has a molecular weight of 900 or less. This is a surface-modified wholly aromatic polyamide fiber characterized by having a layer of a lubricant.

The cation-exchanging and non-ion-adsorbing inorganic compound is a compound that has the ability to exchange cations and also has the ability to adsorb non-ions, and specifically includes silica-alumina,
Silica-magnesia, bentonite, kaolin, fuller's earth, acid clay, activated clay, montmorillonite,
Part-time job site.

These cation-exchanging and non-ion-adsorbing inorganic compounds are solid and fixed to the fiber surface.

The compound (particles) generally have a roughness of about 0.01 to 5 μm. In the present invention, adhesion refers to the fact that it does not come off at all even after severe washing with water or 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 while the fiber surface is softened and biting into the surface of the fiber, and then solidifying the fiber. can. That is, a completely aromatic polyamide ILN is sprayed with a cation-exchangeable and non-ion-adsorbing inorganic compound immediately after spinning, or a completely aromatic inorganic compound is suspended in water. A method is used in which a group polyamide fiber is immersed to adhere inorganic compound particles to the surface of 111, and then hot-stretched or heat-treated at a temperature equal to or higher than the second-order transition point of the wholly aromatic polyamide M fiber.

The wholly aromatic polyamide 11 fiber is, for example, one made of phenylene terephthalamide or a copolymer thereof, which is composed of a predetermined aromatic dicarboxylic acid and an aromatic diamine, but is not particularly limited.

The polyoxyalkylene-containing aliphatic polyester compound is one of polyalkylene glycols such as polyethylene glycol, polypropylene glycol 2-polytetramethylene glycol, or a copolymer thereof, capric acid, and lauric acid.

It refers to esters with one or more types of monobasic acids such as myristic acid, valmitic acid, stearic acid, and oleic acid, or dibasic acids such as adipic acid, azelaic acid, and sebacic acid.

Especially here, the molecular weight is 3000 or more and 15
A substance that is liquid at a temperature of ℃ or higher.

If the molecular weight is less than 3,000, the desired high abrasion resistance strength on the fiber surface cannot be obtained;
If it is not in liquid form at a temperature of 0.degree. C. or higher, it will not only be difficult to handle when applied to the fibers, but also cause solid matter called scum to accumulate on the thread guides during post-processing of the fibers, which is undesirable.

Such a high molecular weight ester compound has high viscosity due to the lateral movement of its molecules, has a strong liquid film, and improves lubricity under extreme pressure. Therefore, even if high contact pressure is exerted between the fibers due to the action of twisting or the like, there is a degree of freedom between the fibers. That is, it reduces the frictional force between fibers, increases the abrasion resistance strength of the fiber surface, and suppresses the decrease in strength due to twisting.

However, on the other hand, because of its high viscosity, the running friction of Il cloth with this formed film increases when it runs on yarn guiding guides, and single yarns are caught by the yarn guiding guides, causing fuzz. It cannot be used alone at all because it causes various problems such as Therefore, in the case of the present invention, it is necessary to use a low-friction side lubricant.

When two types of compounds are used in combination, unless they have an affinity for each other, they are usually compatible with each other, and even if a low-friction lubricant is used, its effect will not be exhibited. Therefore, the lubricant used in the present invention needs to be incompatible with the polyoxyalkylene-containing aliphatic polyester compound.

Furthermore, in the case of the present invention, in advance! [Since the rough surface has been modified to have cation-exchange properties and non-ion adsorption properties, the aliphatic polyester compound containing high molecular weight polyoxyalkylene is preferentially adsorbed to the fiber surface, and therefore the low-friction lubricant is Formed on the coating, the purpose of reducing running friction will be achieved.

As described above, the important point of the present invention is that the extreme pressure lubricant made of an aliphatic polyester compound containing high molecular weight polyoxyalkylene and the low-friction lubricant form a two-layer structure on the fibers. It is.

The lubricant that is incompatible with the polyoxyalkylene-containing polyester compound used in the present invention is an aliphatic lubricant and/or a silicone lubricant having a molecular weight of 900 or less.

Examples of aliphatic lubricants include esters of mineral oil alcohol and basic acids, natural oils and fats, but octyl palmitate, oleyl oleate, and isostearyl oleate are preferably used as low-friction lubricants. It is an ester of a monohydric alcohol and a monobasic acid.

In this case, if the molecular weight exceeds 900, the viscosity will be high and therefore it cannot be used as a low friction lubricant.

In addition, compounds other than aliphatic compounds, such as those having an aromatic ring, have high friction, so they cannot be used either. As a non-aliphatic lubricant, a silicone-based lubricant typified by dimethyl silicone can be used. Among these, dimethyl silicone having a low viscosity of 300 C3t (at 30° C.) or less is preferred for its low friction properties. The treatment of an aliphatic polyester compound (A>) containing poly quaternary-dialkylene between polymers and an aliphatic lubricant (B) with an intermolecular relationship of 900 or less and/or a silicone lubricant on the fibers is as follows: As mentioned above, after fixing the cation-exchanging and non-ion-adsorbing inorganic compound on the fibers, first, the compound (A) is applied to form a film of the compound on the rough surface, and then, The lubricant (B) may be applied thereon, or the compound (A) and the lubricant (B) may be applied at the same time. Even if they are applied simultaneously, the compound <A> is It is adsorbed to the fiber side, and as a result, the same effect can be obtained as if it were applied in several batches.

In addition, during these application treatments, the peeling agent can be treated as an aqueous fiber treatment solution containing water, or as a non-aqueous fiber treatment solution containing the agent in a solvent that does not substantially contain water. Furthermore, any known means such as an oiling roller, a metering oiling nozzle, or a spray may be used as a means for applying the oil.

In addition to the compound (A> and lubricant <8) of the present invention, other compounds such as a training agent may be mixed with the I! miscellaneous treatment agent as the treatment liquid if necessary.

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

<Effects of the Invention> The present invention has the advantage that when running on a yarn guiding guide in the processing process of all, it does not increase the running FJ friction, therefore, it does not cause fuzz or yarn breakage during running, and it is completely aromatic. The purpose of the present invention is to provide a wholly aromatic polyamide fiber that has high surface abrasion resistance while taking advantage of the characteristics such as high strength and high modulus inherent to polyamide fibers.

<Example> The present invention will be specifically explained below using Examples.

Note that the characteristic values used for evaluation in the present invention were measured according to the following method.

(1) Abrasion resistance strength of the fiber surface As shown in Figure 1, both ends of the fiber Y of 1500 denier 1000 filament are attached to a disc 1.2 rotating at a constant rotation <50 rpm), and the fiber is attached to a pulley 3°4. The threads are twisted so that the number of twists is 2 turns at point A, crossed, and then hung on a pulley 5 to which a load of soo g is applied.

The intersection angle of the fibers at point A was 40'', and the length of the repeated reciprocating stroke of the fibers was 50M.

In this way, the time taken to repeatedly rub the fibers against each other until the fibers were rubbed and cut was expressed in seconds, and the abrasion resistance was evaluated.

(2) Coefficient of Running Friction As shown in Figure 2, the fibers Y unwound from the yarn package 1 pass through the yarn guiding guide 2 and are further adjusted to an S-shaped tension compensating center 3 to adjust the tension T1 to 20 g. 11S 6
A 0φ cylindrical friction body 4 was contacted at a contact angle of 180° to measure the exit tension (Tz), and then the yarn bundle was run through a rotating roller 5 with a surface speed of 300 m/win. The friction coefficient at this time was calculated as μ-(1/π)In(Tz/T+).

(31mN strong retention rate (1) Instron tensile testing machine with initial length 25CI
The tensile cutting strength of the fiber sample II was measured in an atmosphere of 20° C. and 65% RH at a tensile rate of 10 α/min, and the strength (9/de) of the fiber was determined from this.

C] Using an Instron tensile test Akebono, a two-strand cord with 40 turns of first twist and top twist per 10 cttt was tested (1
) Measured under the same measurement conditions as ]-do strength (g/de)
I asked for

The strength retention rate was determined from the ratio of these cord strengths to the 111 strength.

(4) Comprehensive Judgment The results of the evaluation using the above measurement methods were comprehensively evaluated, and good to poor was indicated by O to ×.

A para-wholly aromatic polyamide consisting of is spun, washed repeatedly with water, and after washing with water, an aqueous bentonite dispersion is attached and hot-stretched at 500°C to produce non-shedding bentonite.
Fully aromatic polyamide fiber (1500 denier 10
00 filament) was obtained.

Immediately after drawing the wholly aromatic polyamide fibers, a 15% aqueous emulsion having the composition shown in Table 1 was applied to the fibers so that the solid content was 3.5% based on the weight of the fibers, and the fibers were dried and rolled up.

The obtained fibers were evaluated according to the evaluation method described above, and the results are shown in Table 2.

Examples 1-5. Comparative Examples 1 to 6 Terephthalic acid dichloride, paraphenylene diamine, and 3,4'-diaminodiphenyl ether Comparative example 6 in Table 2 is a fully aromatic polyamide fiber to which no cation-exchanging and non-ion-adsorbing inorganic compound is added. The results of a similar comparative evaluation after applying the oil agent of Example 1 are shown.

From these results, it is clear that the present invention exhibits remarkable effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus for measuring the abrasion resistance of an IIM surface. 1 and 2 are disks, 3.4.5 are pulleys, 6 is a load, A is a fiber intersection point, and Y is IIH. FIG. 2 is a schematic diagram of IJAH's running friction coefficient measuring device. 1 is a package, 2 is a yarn guiding guide, 3 is a tension tensioner, 4 is a cylindrical FJ rubbing body, 5 is a rotating roller, T
1. T2 is a tension measuring device.

Claims (1)

[Claims] A fully aromatic polyamide fiber with a molecular weight of 3000 that exhibits a liquid state at a temperature of 15°C or higher is formed by solid cation-converting and non-ion-adsorbing inorganic compounds fixed to the fiber surface.
It has a coating made of the above polyoxyalkylene-containing aliphatic polyester compound, and on the coating is an aliphatic lubricant and/or a silicone lubricant that is incompatible with the polyester compound and has a molecular weight of 900 or less. A surface-modified wholly aromatic polyamide fiber characterized by having a layer of an agent.