JPS6075675A - Aromatic polyamide yarn impregnated with wettable particle, its production and packing material or rope containing same - Google Patents

Abstract

A filament yarn of aromatic polyamides impregnated with solid particles of a fluorine-containing polymer and/or graphite. The solid particles are incorporated into the yarn by very uniformly distributing them over the filaments in that the solid particles are applied to the yarn from an aqueous dispersion and the yarn is subjected to a blowing treatment while feeding them at an excess feed rate or not. The yarn thus impregnated is first of all intended to be processed into a packing material or rope. In figure (2), the aramid yarn (13) is passed through a bath (15) containing an aqueous dispersion of PTFE and/or graphite particles and a blow box (18).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a yarn consisting entirely of aromatic polyamide, which is impregnated with a dispersion of solid lubricious particles, such as particles of a fluorine-containing polymer and/or graphite. Regarding. The invention also relates to a method of making such a yarn and a backing material such as a backing box trap containing the yarn.

Yarns of the above-mentioned type are known from U.S. Pat. The material is listed. Before or after braiding, the yarn may be impregnated with solid particles of fluorine-containing polymer and a dispersion of starch. Polytetrafluoroethylene (P
It is believed that the dispersion containing TFIII) particles contributes to the sealing properties of the final product in the form of a backing material. Although the results obtained with the backing material disclosed in US Patent J% 437118Q are reasonable, the present invention makes it possible to improve them.

With the above-mentioned purpose, yarns of the above-mentioned type consisting entirely of aromatic polyamides have been launched for the first time for use in backing materials. This yarn, according to the invention, is made of M4 from a number of endless filaments, with solid particles present on the filaments, which are distributed over the filaments by subjecting the yarn to spraying or treatment while wet. It is characterized by: In this process the filaments are generally entangled and intertwined. According to the invention, the solid particles can consist of a fluorine-containing polymer such as polytetrafluoroethylene or graphite. However, it is also possible to use mixtures of solid particles of fluorine-containing polymers and graphite. The wet yarn that is subjected to the spray treatment according to the invention has bulky properties, which makes the yarn of the invention particularly suitable for uptake of lubricants.

Because of their lofty properties, the yarns readily absorb many lubricants, which makes the yarns of the present invention particularly suitable for forming into backing materials. As lubricants, mention may be made of those commonly used in the backing material industry for impregnating yarns, such as paraffin oil, silicone oil or molybdenum disulfide or other suitable lubricants, depending on the field of use of the backing material made. selected depending on.

Particularly in the present invention, since the yarn is bulky, the lubricant absorption capacity of the yarn containing polyfluorocarbon particles is limited by the solid F
It is in the range of 20 to 50% by weight, preferably of the order of 35% by weight, based on the weight of the dry yarn provided with TF'F and/or graphite particles. The lubricant is believed to contribute to the gas and/or liquid seal and the frictional behavior of the backing material. After being continuously impregnated with FTPK particles, braided to form a backing material, and impregnated with a lubricant, the aramid yarn according to the invention, high gas and/or
Or a long service life can be guaranteed in terms of liquid sealing and lubrication effect. According to the invention, the yarn is +, OOU
~2 to 000 filaments, preferably about 5000
Contains book filaments, linear density of yarn is 150~T
)00 D tex, preferably on the order of 850 tex. According to the invention, the yarn contains a relatively small proportion of solid FTFB and/or graphite particles, i.e. less than 60 needles, preferably between 10 and 45% by weight, in particular about 20% by weight, based on the dry weight of the yarn without solid particles. It is sufficient to include According to the invention, the size of 80% of the solid particles is preferably in the range of about 0.01 to 1 μm. The yarn of the present invention is particularly characterized in that the solid particles are uniformly applied to the yarn and preferably account for at least 50 filaments, preferably 70 to 100% of the number of filaments, as measured on a random cross-section of the yarn.
is characterized in that it is equipped with one or more of said particles.

The special formation of the yarn, due to the wet blowing process, allows for a particularly even distribution of the PTFE particles in the cross section of the yarn. As a result, the FTIP present in the yarn
The function of the IC particles, ie the promotion of the sealing action of the backing material, is maximized efficiently. The FTFB particles also increase the chemical resistance of the backing material and reduce friction. The yarns of the invention are therefore suitable for long periods of use, even under high dynamic loads, e.g. in the case of high-speed shafts and reciprocating parts, at elevated temperatures and pressures and/or in chemically aggressive media. It can be formed into a backing material that guarantees a very good seal.

Furthermore, as a result of the uniform distribution of FTFK particles in virtually every filament of the yarn, only a relatively small amount of FTFE particles is required to make the yarns of the present invention a sufficient hermetic backing material. It is enough. Another advantage of the uniform distribution of PTFFi particles in the yarns of the present invention is that the backing braided from the yarns does not need to be further impregnated with a dispersion containing FTFK particles.

The yarns of the invention have been particularly developed to be suitable for making backing materials, such as backing box backings, which are widely used for the sealing of rotating shafts and reciprocating members in mechanical construction. In the production of backing materials, FTFI! A number of yarns of the invention impregnated with l and/or graphite particles can be braided in a backing material braiding machine to form a backing material having, for example, a rectangular cross section. Braided backing materials are generally impregnated with lubricants such as special oils, fats, or other substances required in view of the use of the backing material. In the finished backing material according to the invention, the weight proportion of solid particles can be less than 60%, preferably less than 10%, relative to the dry weight of the aramid yarn excluding solid particles.
~45%. The present invention particularly relates to solid FTFB and/or
or a backing material of aromatic polyamide yarn impregnated with graphite particles, preferably about 20 to 50% by weight relative to the weight of the dry yarn provided with a large amount of lubricant, i.e. solid particles. a backing material comprising an amount of

A simple and efficient method of making the yarn of the present invention, which involves applying a dispersion of solid particles of fluorine-containing polymer and/or graphite to the yarn, involves applying the yarn in the wet state to a fluid under pressure, such as air. Spraying is characterized by a process in which the solid particles are distributed in the filaments and the filaments are generally entangled with each other.

In a preferred embodiment of the method of the invention, the yarn is
The spraying process is carried out after the dispersion of solid particles of fluorine-containing polymer and/or the dispersion containing graphite particles has been applied to the yarn. Alternatively, according to the invention, a dispersion of particles of fluorine-containing polymer and/or graphite is
It can be applied to the yarn under pressure and then sprayed directly onto the yarn. In the spraying process, the air is 3
Used at ~10 bar absolute pressure.

In a preferred embodiment of the method of the invention, FTIFB
, preferably positively charged, is applied to the yarn as an aqueous dispersion with substantially the following composition: 45-75% by weight, preferably about 58% by weight FTPB.
Particles; 50-20% by weight of water, preferably about 40% by weight; no more than 5 parts by weight, preferably about 55% by weight of a wetting agent based on alkylphenoxyethanol.

Graphite particles are applied from an aqueous dispersion,
It may contain, for example, about 18% by weight graphite, 82% by weight water and a non-ionic wetting agent.

Particularly favorable results may be obtained if the FTFB and/or graphite particles are applied to the yarn from the dispersion using a kiss roll. Optionally J) PTFI and/or graphite particles can be applied by passing the entire yarn through this dispersion.

In accordance with the present invention, the yarn is preferably sprayed at least 1% faster than it exits the process, preferably from about 3 to 6 q
b The spray is fed into the process at an excessive velocity. However, according to the invention, a satisfactory distribution of solid particles on virtually linear filaments of yarn can also be obtained if the yarn is subjected to the blowing process without using excessive feed rates. . In processes where a subdued feed rate is not used, the yarn is passed through the spray zone with virtually no tension. It should be noted that the yarns of the invention are particularly suitable for use in making lobes with an outer diameter of e.g. consisting of or made by braiding. According to the invention, the yarn used in such lobes contains less than 10 parts by weight, preferably about 5 parts by weight, of solid particles.

The invention will be illustrated with reference to the accompanying drawings.

Figure 1 shows that PTF]In is sprayed on the yarn before the process.
1 shows a device for poisoning particles;

FIG. 2 shows a slightly modified apparatus for carrying out the method of the invention.

In the embodiment shown in FIG. 1, the method comprises five packages of untwisted aramid filament yarn,
start from. Each aramid yarn 2 in the package is
With a linear density of 1000 filaments and 168 tex, the finish applied to the yarn during spinning is approximately α8
Including chi. Five aramid filaments - yarn 2 are
It is collected by a schematically illustrated yarn guide 3 and driven by drive rolls 4,5.
is withdrawn from the starting package 1 by. The collected yarns then run on kiss rolls 7 which rotate in an aqueous dispersion 8. The focused filament yarn, moistened in this way and provided with FTFFi and/or graphite particles, is blown into the box 9 by means of an air nozzle 10 at a speed faster than the speed at which the yarn exits the box. Supplied by The nozzle 10 may be of the type described by Akaneko in US Pat. No. 3,302,386. The sprayed and impregnated yarn is delivered to nine spray boxes by a pair of driving tension rolls 11 and 12. The rolls 11, 12 also have a slow peripheral speed, so as to ensure that the yarn is fed to the air nozzle 10 with a sufficiently high overfeed rate. Heated tension roll 11. After leaving j2, the dry yarn can be further lubricated if desired and wound into a knot cage. The spraying is carried out in box 9 with a focused yarn 5X consisting of five basic yarns 2.
168 is treated with air at an absolute pressure of 5 bar and the yarn is fed with an overspeed of 3%. Alternatively, the focused yarn can consist of ten basic yarns. Such a focused and interrupted yarn of 10 x 168 tax is blown in box 9 with air at an absolute pressure of 10 nos.
The yarn overfeed rate is 60%.

If the yarn is processed without using an overfeed speed, it can be fed into the spray zone at a speed of 60 m/min and exit therefrom.

FIG. 2 shows an example of a somewhat modified apparatus for carrying out the method of the invention. Untreated aramid yarn 13 is fed by a pair of rolls 14 at the desired specific speed. After leaving the roll 14, the yarn is passed through a bath 15f containing an aqueous dispersion of FTFK and/or graphite particles.

In the bath the yarn is passed through two or more guide rolls (not shown). After leaving the bath 15i, the yarn passes upwards through the feed pipe 17, which terminates in the spray box 18. Spraying is in Box 18, and US Patent I
There is a nozzle (not shown) of the type described in I&13302386. The advantage of the feed vibrator 17 is that any excess dispersion that is blown out of the yarn without being incorporated into the yarn returns to the bath through this pipe 17g.

After spraying has been subjected to treatment, the impregnated yarn 1? The outlet opening 20'tl - is sprayed through the box 1B'
i leave. The yarn is pulled out of the spray box 18 by a drive roll 24 with a separator roll 21. Roll 24 can be heated to dry the yarn. The yarn thus impregnated and dried can be formed into a package via a traverse mechanism 22. The peripheral speed of roll 24 is slower than that of roll 14, so that the yarn is blown through the box at the particular overfeed rate desired.

It has been found that favorable results can be obtained by the method shown in FIG. That is, in the cross-section of the yarn, the PTFI particles are distributed very uniformly on the filament of the vessel, mainly due to the following process conditions: peripheral speed of the kiss roll: 42 m/min; Peripheral speed: 595□/min (yarn feed rate), Peripheral speed of roll 11.12: sam/min (yarn exit speed), Excess feed rate of yarn at nozzle with absolute pressure of air: 3-4 bar, Composition of the dispersion:
56.5 parts by weight PTFK particles, 40 parts by weight water and 5 parts by weight
5 parts by weight Triton

The dispersion used was of the type commercially available from Kogyo under the trademark FluOn, in which FTF
B particles have a negative charge. However, other dispersions can also be used in the process according to the invention.

Dispersions in which particles of fluorocarbon compounds, in particular particles of polytetrafluoroethylene (PTFE), are positively charged can be advantageously used.

This above-mentioned dispersion is described in detail in West German patent %+2644152. It is believed that the use of a dispersion containing positively charged PTFI particles results in better adhesion of these particles to the filaments of the yarn.

It must be added that the excessive feed rate used in the wet spraying process of the present invention has a significant effect on the structure of the yarn. In particular, entanglement or entanglement of the filaments with each other is highly dependent on the overfeed rate. At low overfeed rates, such as 1 inch, the untwisted yarn loses its smooth appearance and becomes somewhat taut as a result of entanglement and/or entanglement of the filaments with each other and the formation of loops within the filaments. be textured or textured. The intertwining and entanglement of yarn filaments and the production of yarns with a large number of loops are themselves known in textile technology and are described in US Pat.
It is described in 09. The tangle and entanglement of the yarn filaments using the spraying process and excessive feed rate of the yarn gives the yarn bulk properties. High excess feed rates make the yarn very bulky. Yarns moistened with PTFE and/or graphite dispersions and subjected to spray treatment have lofty properties, which are influenced by the degree of impregnation with solid particles.

Impregnation of the yarn with a higher percentage of FTFF particles is associated with lower bulk properties as a result of adhesion of the PTFF particles. In other words, the degree of impregnation to be chosen depends on the desired bulk properties.

In producing the yarns of the present invention, the preferred overfeed rate is in the range of 3-6%, which results in yarns with more or less loop-like characteristics. The presence of internal and/or external loops formed in one or more filaments of the yarn and the resulting bulky appearance are characteristic of certain embodiments of the yarn according to the invention. It is particularly surprising that even a fairly low overfeed rate of 3% results in sufficiently bulky yarns that are highly suitable for further processing into backing materials. However, excessive feed rate sonic blowing can cause FTFB and/or
Or a particularly uniform distribution of graphite particles is achieved.

The spraying process constitutes an essential element of the invention with a view to obtaining a very good distribution of solid particles on the filaments of the yarn.

Smooth, non-air-blown aramid filament yarns can be FT processed using an applicator roll or impregnation.
A dispersion containing FFj particles may be treated. But experiments show that in that case PTFI! ! The particles stick to the outer periphery of the yarn in the form of glaze-sized clumps, as seen in the high-magnification photograph of the yarn section mj. The photographs also show that almost no FTFB particles are attached to the filaments that are within the outer periphery of the yarn. Therefore, aramid filament yarns that are not air treated can be uniformly impregnated with pTFi particles and are not well suited for processing into backing materials.

The aforementioned absorption capacity of the aforementioned yarn with respect to lubricants such as paraffin oil, silicone oil, molybdenum disulfide, etc. is called oil absorption capacity and is measured as follows: Pre-impregnated with FTFB particles A 1 m long piece of aramid filament yarn was impregnated with paraffin oil having a viscosity of 72 centipoise (as measured by the Brookfie 14 method) by dipping the yarn in a tray containing paraffin oil at room temperature, and then soaking the tray. Place in vacuum chamber for 15 minutes. The yarn thus impregnated is suspended by one end so that any paraffinic oil that cannot be retained in the yarn can drip from the other free end. The amount of paraffin oil absorbed, which is a measure of the oil absorption capacity, is determined by weighing. A second weighing of the oil-impregnated yarn is carried out as soon as, after at least 24 hours, dripping is no longer visible at the free end of the yarn. To measure oil absorption capacity, first weigh this 1? P! This is done on long pieces of yarn that are still dry and impregnated with FTFB and/or graphite particles.

First weighing results in '4A weight units (dry yarn + FTF11i and/or graphite particles).

The result of the second weighing is B weight units (dry yarn 10F TVFi and/or graphite particles + paraffin oil). The oil absorption capacity C assumed in the present invention can be calculated from the following formula: Results A and B of the first and second weighings
are, for example, 1000 and 1350 weight units, respectively, the dry aromatic polyamide yarn mentioned elsewhere in this specification is understood to be an aramid yarn dried at 100° C. to a moisture content of 6 g. I must add that it should. This moisture content is 20℃, 6
Defined at 5% relative humidity.

The term wholly aromatic polyamide, as used in connection with the present invention, refers to a polyamide consisting entirely or substantially of repeating units of the general formula. Here, Ai, A, and A3 are different from each other or the same, divalent, or hard residues containing - or two or more aromatic rings, which can also include heterocycles; The chain-extending bonds of the groups may be in opposite positions with respect to each other, or may be oriented in parallel or opposite directions. Examples of these residues include
1.4-phenylene, 484'-biphenylene, 1.5
-naphthylene and 2,6-naphthylene. They may or may not contain substituents such as nitrogen atoms or alkyl groups. Regarding the composition of the aramids, it is added that they can optionally contain up to 35 mol % of other groups such as m-phenylene groups, non-hard groups such as alkyl groups or ether groups, urea groups or ester groups. Must be. As examples of aramids, mention may be made of poly-p-benzamide, poly-p-phenylene terephthalamide and copolymers thereof. According to the invention, it is preferred to use yarns of poly-p-phenylene terephthalamide (PPDT).

As a fluorine-containing compound which can be advantageously used for the yarn according to the invention, polytetrafluoroethylene (FTFB
), polyhexafluoropropylene, polychlorotrifluoronithine, polyvinylidene fluoride, tetrafluornithine hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, fluorosilicone elastomer, polyfluoroaniline, tetrafluor Ornithine trifluoronitrone methane copolymer, graphite fluoride
Which can be mentioned.

West German Patent No. 2326824 discloses that 50-80% by weight of PT
An appendix must be added that describes a blended yarn consisting of FE filaments and 50-20% by weight of aromatic polyamide filaments. This blend yarn is FTFI! ! It can be coated with particles and in a braided form used as a backing material. Are these two yarns FT? Before being coated with B particles, they are focused, which is sometimes described in US patents &
The spraying described in 311m151 can be carried out by the process. This spraying process results in a smooth curve with no loops and therefore is not bulky or textured. PTIPF
Coating with t-particles ultimately results in these particles being completely on the outside of the yarn. Moreover, given that the yarn according to DE 232/1826 is a blend of two yarns with widely different properties, it is less uniform than one yarn of the same material.

European patent 1'h0032744 also discloses a wholly aromatic polyamide yarn provided with a fluorine compound-containing polymer. In this case, the fluorine compound is
It is not present on the fiber in the form of separate particles, but in the form of a continuous coating. Since the FTFK is not present on the fiber in the form of separate particles, this known yarn is not suitable for use as a backing yarn.

Canadian Patent Island No. 995,288 discloses a hovercraft skirt comprising an elastomer-coated fabric made of looped yarn textured with pressurized air. The yarn preferably consists entirely of aromatic polyamide. Thus, the aramid looped yarn itself, textured under air pressure, is disclosed in Canadian Patent No. 9955.
88, but their field of use is quite different and their use in combination with PTFII:particles is not suggested at all.

It should be added that various modifications are possible within the scope of the present invention, and these are included in the present invention.

[Brief explanation of drawings]

FIG. 1 shows that in the present invention, spraying is performed on the yarn [PTFII!] before the process. Apparatus for Applying Particles FIG. 2 is a flow diagram of another modified apparatus for carrying out the invention. 1.2,000-1-beans#, ,-W! L-U 肱-(, ka8,
Showa (Fui 1//Sword Otsu 1) Commissioner of the Patent Office Manabu Shiga 1, Display of the case Showa Kurimochige 1 Sakuhan No. 3111511) Relationship with case No. 3 Applicant 4, Attorney I Cili Tokyo 2-8-1-g' Toranomon 2-chome, Minato-ku (
IJL's Akira Kihiru) (11j, Live 03 (502)
147 G (Substitution)] 5 Correction instruction El lit:
1 1933 10JJ 9 Ex. 6. Column Ω of originator and applicant of the application to be amended = power of attorney - letter of attorney - letter of attorney written by Kumaho → → Engraving of drawings. (No change in content)7
, The content of the amendment is as per the attached sheet.

Claims (1)

Claims: 1. A yarn consisting of a wholly aromatic polyamide impregnated with a dispersion containing solid lubricious particles,
The yarn is characterized in that it is composed of a number of endless filaments on which solid particles are present, and the solid particles are distributed over the filaments by subjecting the yarn to a spraying treatment in a wet state. Yarn. 2. The yarn according to claim 1, wherein the filaments are intertwined and entangled. (5) The absorption capacity for lubricants of the solid particle-containing yarn is
28 for the weight of dry yarn equipped with solid particles
3. A yarn according to claim 1 or claim 2 in the range .about.50 weight. Yarn according to claim 1, having a plurality of loops formed in one or more filaments. 4. A yarn according to claim 3, wherein the S yarn has both internal loops and loops projecting therefrom. & The yarn contains 1.000-20,000 filaments and the linear density of the yarn is 150-1000 tex
A yarn according to any one of claims 1 to 5 within the scope of. 2. A yarn according to claim 1, comprising 60 square meters of solid particles relative to the weight of the dry yarn without solid particles. a. Claims in which the solid particles are uniformly applied to the yarn such that at least 50 of the filaments, measured in a random cross-section of the yarn, are provided with one or more solid particles. Yarn according to any one of ranges 1 to 7. 2. The yarn according to any one of claims 1 to 8, wherein the solid particles have an 80 factor size of less than 1 μm. 1 [1, 10 for dry weight of yarn without solid particles
7. A yarn according to claim 6 containing ~45% by weight of solid particles. 11, 100 for dry weight of yarn without solid particles
Claims 1 to 9 containing full weight percent solid particles
Yarn as described in any one of the paragraphs. 12. A yarn consisting of a wholly aromatic polyamide impregnated with a dispersion comprising solid lubricious particles,
The yarn is made up of a number of endless filaments on which solid particles are present, and the solid particles are distributed over the filaments by subjecting the yarn to a spraying treatment in a wet state. A backing material comprising: 15. Claim 12 in which the weight proportion of solid particles is less than 60 times the weight of the dry yarn without solid particles.
Backing material as described in section. 14. Backing agent according to claim 12 or 13, comprising a lubricant in an amount of 20 to 50% by weight, based on the dry yarn weight of aromatic polyamide provided with solid particles. 15. A rope constructed by twisting or braiding two or more ropes, the rope being a yarn consisting entirely of aromatic polyamide impregnated with a dispersion containing solid lubricating particles. , the yarn is composed of a number of endless filaments on which solid particles are present, the solid particles being distributed over the filaments by subjecting the yarn 7 to a spraying treatment in a wet state. A rope characterized by: 1f, impregnated with a dispersion containing solid lubricious particles;
A yarn consisting entirely of aromatic polyamide, the yarn being composed of a number of endless filaments on which solid particles are present, the solid particles being sprayed onto the yarn in a wet state during treatment. A method of making a yarn distributed on a filament by applying a dispersion of lubricating particles to the yarn, the method comprising applying a dispersion of lubricating particles to the yarn, the yarn being exposed to a fluid under pressure while wet. A method characterized in that the spraying is subjected to a process, resulting in a homogeneous distribution of solid particles on the filament. 1Z. The method of claim 16, wherein the fluid is sprayed onto the yarn generally transversely to the direction of yarn movement. 17. The method of claim 16, wherein the yarn is subjected to spraying treatment after applying the dispersion containing solid particles to the yarn. 19. Claim 16 or TF 17 in which the solid particle-containing dispersion is sprayed onto the yarn during the process.
The method described in section. 20. The method of claim 19, wherein the solid particle-containing dispersion is applied directly to the filaments of the shearn by spraying the yarn under pressure. 21. Claim 1 in which the negatively charged solid particles of the fluorine-containing polymer are applied to the yarn in the form of an aqueous dispersion.
The method described in Section 6. 22. The method of claim 16, wherein the positively charged particles of fluorine-containing polymer are applied to the yarn in the form of an aqueous dispersion. 25. The composition of the aqueous dispersion is approximately 45-75% by weight of PTFB particles, 50-20% by weight of water, not more than 5% by weight of a wetting agent based on alkylphenoxyethanol, or The method according to paragraph 22. 17. The method of claim 16, wherein the 2L yarn is fed into the process at a faster rate than it exits the process. 25. The method of claim 24, wherein the excess feed rate is at least one factor. 26. A method according to claim 16 or claim 17, wherein the yarn is subjected to a blowing process without using an excess feed rate.