WO1998024559A1

WO1998024559A1 - Thioesters as boundary lubricants

Info

Publication number: WO1998024559A1
Application number: PCT/US1997/021399
Authority: WO
Inventors: Elbert H. Mudge
Original assignee: Henkel Corp
Current assignee: Henkel Corp
Priority date: 1996-12-05
Filing date: 1997-12-02
Publication date: 1998-06-11
Anticipated expiration: 1999-06-05

Abstract

A textile fiber finish composition comprising: (a) from about 95 to about 99 % by weight of a lubricant component; and (b) from about 1 to about 5 % by weight of a boundary lubricant additive having the formula (I): R1-OOCCH2CH2-S-CH2CH2COO-R2 wherein R1 and R2 are each, independently, a C8-C18 alkyl group, all weights being based on the weight of the composition.

Description

THIOESTERS AS BOUNDARY LUBRICANTS

Field of the Invention:

This invention relates to a composition and process for decreasing fiber-

to-fiber and fiber-to-metal friction, as well as the scroop, in synthetic continuous

filament fibers and scroop in staple fibers. More particularly, it has been

surprisingly found that thioesters provide enhanced-tooundary lubrication in fiber

finish compositions, thereby decreasing the fiber-to-fiber and fiber-to-metal

friction coefficients, as well as scroop, in synthetic textile fibers.

Background of the Invention:

Finishing compositions are generally applied to textile fibers to improve

their subsequent handling and processing. Fiber finishes play an important role

in assisting the fiber producer to manufacture the product, and enable the fiber

producer's customers to carry out the required yarn and fabric manufacturing

processes to obtain the finished textile product. The formulation and amount of

finish composition applied depend on a number of variables which include the

chemical composition of the textile fiber, the particular stage in the processing

of the fiber, and the end use under consideration.

For example, compositions referred to as "spin finishes" are usually

applied to textile fibers after extrusion. These or other finishes which may be

applied to yarn prior to knitting or winding, and to fiber tows prior to or at the time

of crimping, drying, cutting, drawing, roving, and spinning, or to staple fibers prior

to carding, i.e., web formation, and subsequent textile operations such as yarn

manufacture or preparation of nonwoven webs are commonly called secondary or over-finishes. Such finishes provide lubrication, prevent static build-up, and

afford a slight cohesion between adjacent fibers.

The application of such finishes is generally accomplished by contacting

a fiber tow or yarn with a solution or an emulsion comprising at least one

component having antistatic properties. In addition to a lubricant and anti-static

agent, wetting agents, additives such as antioxidants, biocides, anti-corrosion

agents, pH control agents, as well as emulsifiers are also commonly found in

such finish mixtures. Finish compositions can also be applied to tow, yarn, or cut

staple by spraying.

Acceptable finishes must fulfill a number of requirements in addition to

providing desired lubricating and antistatic effects. For example, they should be

easy to apply (and to remove if desired), they should have good thermal and

chemical stability, they should not adversely affect the physical or chemical

properties of the fibers to which they are applied and they should aid the

subsequent processes to which the treated fibers are subjected, they should not

leave residues on surfaces or cause toxic fumes or undesirable odors, they

should provide for rapid wetting of fiber surfaces, they should be water-soluble

or emulsifiable or solvent-soluble, they should have good storage stability, they

should be compatible with sizes, nonwoven binders and other fiber treatments,

they should not attract soil or cause color changes to the fibers, they should not

interact with frictional elements used in texturizing and they should not be

corrosive to machine parts. The purpose of a fiber finish is to provide fiber to metal lubrication and

fiber to fiber cohesion, as well as eliminate static electricity. Although much of

the basic work to elucidate the mechanisms of lubrication was done in the distant

past, results of this work continue to be used to understand and apply results of

5 frictional testing to current problems and the development of new finishes.

The contribution of frictional and antistatic properties can be observed

throughout fiber manufacturing and processing. An example is the case of a low

denier polypropylene staple fiber which is to be carded into a web and thermally

bonded for some disposable nonwoven application. This requires a formulation

i o which in conjunction with the fiber crimp, contributes a relatively high fiber to fiber

friction which is important in insuring a carded web with good cohesion,

uniformity, and integrity, and which compensates for the low stiffness of the

fibers. Low fiber to metal friction is also a key factor in the processing of these

staple fibers which have diameters on the order of only 15 to 20 micrometers.

15 Another example involves a slit film or ribbon type yarn intended for

woven carpet backing for tufted carpets. During its manufacture, good wetting

of the fiber surface by the finish and moderate frictional coefficients are required.

For tufting, however, relatively low fiber to metal friction is a very important

feature because of the action of tufting needles on the backing fabric.

2 o Finally, low fiber to fiber friction is a highly desirable feature of continuous

filament yarns used in cordage applications which involve twisting and plying to

form compact structures which have a large amount of fiber to fiber contact. Low

friction is desirable since it is generally associated with high flex resistance, high energy absorption and therefore, long life.

A different area of fiber-to-fiber friction is concerned with continuous

filament yarns. This may be illustrated by some examples within the fiber

manufacturing plant: package building in spinning and filament drawing or tow

drawing are the major steps where the fiber-to-fiber friction is of critical

importance. In yarn processing, yarn delivery in coning, stitch formation in

knitting, filament damage in braiding, strength and elongation in cordage,

slippage of weave in fabric, yarn-to-fabric friction in sewing, are some of the

areas where yarn-to-yarn friction is important.

Summary of the Invention:

The present invention is directed to a textile fiber finish composition

containing from about 95 to about 99% by weight of a lubricant component and

from about 1 to about 5% by weight of a boundary lubricant additive having the

formula I:

R₁-OOCCH₂CH₂-S-CH₂CH₂COO-R₂ (I)

wherein R, and R₂ are each, independently, a C₈-C₁₈ alkyl group, all weights

being based on the weight of the composition.

The present invention is also directed to a process for treating a textile

fiber involving contacting the fiber with from about 0.3 to about 2.0% OWF (on-

weight-of-fiber) of the above-disclosed textile lubricant composition.

Description of the Invention:

Other than in the operating examples, or where otherwise indicated, all

numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as being modified in all instances by the term "about."

The two primary components of the textile fiber finish composition of the

present invention are the lubricant component and the boundary lubricant

additive.

5 The lubricant component of the fiber finish may be selected from the

group consisting of C₈.₂₂ fatty acids, synthetic hydrocarbon oils, alkyl esters such

as tridecyl stearate (EMEREST® 2308) which is the reaction product of tridecyl

alcohol and stearic acid, polyols such as glycerin, and polyol esters such as

trimethylol propane tripelargonate (EMERY® 6701) and pentaerythritol

l o tetrapelargonate (EMERY® 2484).

The lubricant component of this invention is emulsifiable and capable of

forming a stable emulsion with water. By the term "stable emulsion" it is meant

that the emulsion is stable at the time of application of the fiber finish

composition onto the yarn surface. This is meant to include oil-in-water finishes

15 which may be mixed just prior to their application to the yarn surface and which

may be stable only under conditions of mixing and application. Typically,

however, the finish will be mixed well prior to yarn application and then applied

via various applicators from a storage tank or the like and thus the emulsion

must be stable for extended time periods. It may also be desirable to include,

20 as part of the lubricant component, an antistatic agent to aid in controlling the

formation of static electricity during fiber processing. Thus, other components

which may also be used as part of the lubricant of the present invention include

emulsifiers and antistatic agents. An emulsifier may be employed in the composition of the present

invention, if required. The emulsifier may comprise any suitable emulsifying

agent. Typical emulsifiers include an unethoxylated ester such as sorbitan

monolaurate, an ethoxylated ester such as ethoxylated sorbitan monooleate,

ethoxylated C₈.₂₂ fatty acids such as the reaction product of ethylene oxide with

pelargonic acid to form PEG 300 monopelargonate (EMEREST® 2634) and

PEG 400 monopelargonate (EMEREST® 2654), the reaction product of ethylene

oxide with coconut fatty acids to form PEG 400 monolaurate (cocoate)

(EMEREST® 2650) and PEG 600 monolaurate (EMEREST® 2661), and the like,

and an ethoxylated alcohol such as ethoxylated C^-C^ alcohol or combination

thereof. An alkali metal soap of a fatty acid such as potassium oleate may be

included with an ethoxylate emulsifier, but it is not necessary. Preferred

emulsifiers include an ethoxylated sorbitan monooleate (POE(5)) such as

commercially available from Henkel Corporation, Mauldin, South Carolina, under

the tradename EMSORB® 6901 ; POE (9) oleic acid under the tradename Emery

2646; and a polyethylene glycol ether of secondary alcohol commercially

available under the tradename TERGITOL® 15-S-3 from Union Carbide

Corporation, Danbury, CT.

An antistatic agent which may be employed generally comprises any

suitable anionic, cationic, amphoteric or nonionic antistatic agent. Anionic

antistatic agents are generally sulfates or phosphates such as the phosphate

esters of alcohols or ethoxylated alcohols. Cationic antistatic agents are typified

by the quaternary ammonium compounds and imidazolines which possess a positive charge. Examples of nonionics include the polyoxyalkylene derivatives.

The anionic and cationic materials tend to be more effective antistats.

As was mentioned above, if an emulsifier and/or an antistatic agent are

used, they will comprise a part of the lubricant component, in addition to those

lubricant component candidates already disclosed.

The boundary lubricant additive used in the present invention is a

thioester having the formula I:

R_rOOCCH₂CH₂-S-CH₂CH₂COO-R₂ (I)

wherein R_Ϊ and R₂ are each, independently, a C₈-C₁₈ alkyl group.

Examples of thioesters suitable for use as a boundary lubricant additive

in the textile lubricant composition of the present invention include, but are not

limited to, thiodipropionate derivatives such as di-2-ethylhexyl thiodipropionate,

di-hexyldecyl thiodipropionate, di-lauryl thiodipropionate, and the like,

commercially available from Henkel Corp. under the tradename STANDAPOL®.

A particularly preferred thioester for use in the present invention is di-isotridecyl

thiodipropionate, commercially available from Cytec Corporation under the

tradename CYANOX® 711.

According to one embodiment of the present invention, there is provided

a textile lubricant composition containing from about 95 to about 99% by weight,

and preferably from about 98 to about 99% by weight of a lubricant component,

and from about 1 to about 5% by weight, and preferably from about 1 to about

2% by weight of the above-disclosed boundary lubricant additive, all weights

being based on the weight of the textile lubricant composition. In addition to the lubricant component and boundary lubricant additive,

other textile finishing components may also be present in the textile fiber finish

composition of the present invention. Examples thereof include, but are not

limited to, wetting agents, biocides, anti-corrosion agents, and pH control agents.

The textile fiber finish composition of the present invention may be applied

to virtually any type of fiber material including glass, cellulosics such as acetate,

triacetate, rayon, non-cellulosics such as acrylics, modacrylic, nylon, aramid,

olefins such as polyethylene and polypropylene, polybenzimidazole, polyesters

such as polyethylene terephthalate and polybutylene terephthalate or

copolyesters thereof, saran, spandex and vinyon.

According to another embodiment of the present invention, there is

provided a process for lubricating a textile fiber in order to reduce fiber-to-fiber

and fiber-to-metal friction coefficients, as well as scroop, involving contacting the

fiber to be treated with the above-disclosed textile fiber finishing composition.

The process involves applying from about 0.3 to about 2.0% OWF ("on the

weight of the fiber"), and preferably from about 0.5 to about 0.8% OWF of the

textile fiber finish composition onto the fiber.

As was mentioned previously, the textile fiber finish composition will

typically be applied onto the fibers to be treated in the form of an aqueous

emulsion. Thus, the fibers will be contacted with the fiber finish composition at

a percent actives concentration ranging from about 2 to about 20% actives, and

preferably from about 8 to about 10% actives.

The present invention will be better understood from the examples which follow, all of which are intended to be illustrative only and not meant to unduly

limit the scope of the invention. Unless otherwise indicated, percentages are on

a weight-by-weight basis.

Example I

A textile lubricant composition for fiber and textile applications was

prepared having the following formulation.

Component %/wt.

(a) diisotridecylthiodipropionate 1.0

(b) coconut oil 49.0

(c) POE(16)hydrogenated castor oil 15.0

(d) POE(5)C₈.₁₀/C₁₆.₁₈ ether carboxylate methyl ester 22.0

(e) oleic diethanolamide 8.0

(f) sulfated castor oil, sodium salt 5.0

100.0

The ingredients listed above were mixed together at ambient

temperature using agitation to form a textile lubricant composition in

accordance with the present invention. The lubricant composition was then

applied onto nylon-6,6 fibers at 0.7% OWF. A Comparative Example was also prepared having the following

formulation:

Component %/wt.

(a) coconut oil 50.0

(b) POE(16)hydrogenated castor oil 15.0

(c) POE(5)C₈.₁₀/C₁₆.₁₈ ether carboxylate methyl ester 22.0

(d) oleic diethanolamide 8.0

(e) sulfated castor oil, sodium salt 5.0

100.0

Lubricant Composition Evaluations

Frictional properties can be readily measured by applying known

amounts of finish composition to yarns under controlled conditions in the

laboratory. Recognizing that laboratory measurements at best only simulate

actual use conditions, they have nevertheless been found to be a reasonably

good predictor of behavior. One of the well-known instruments for performing

frictional measurements is the Rothschild F Meter. In case of fiber to metal

friction, the measurement is carried out by pulling a yarn around a circular

metal pin under conditions of known pre-tension and angle of contact. The

output tension is measured and the coefficient of friction determined from the

capstan equation

TJT, = e ^{μ θ}

where T, and T₂ are the incoming and outgoing tensions respectively, θ the angle of contact in radians, and μ the coefficient of friction. The Rothschild

instrument calculates and plots the coefficient of friction automatically. Some

prefer to use the value of T₂ - T, as a measure of the frictional force since

strictly speaking the capstan equation is not accurately obeyed by

compressible materials such as fibers.

There are a number of variables, both mechanical and physical, in

addition to the pretension and angle of contact, which can influence friction

results. Some of these are speed, surface roughness, surface temperature,

ambient temperature and humidity, finish composition viscosity, uniformity of

finish composition application, finish composition concentration on the fiber,

and fiber size and shape. Thus, when performing laboratory frictional

experiments to determine the performance of a finish composition, one should

select a condition related to that which the yarn will be exposed, such as for

example, frictional measurements against a heated surface.

The fiber to fiber friction measurement is carried out in a similar way

except that the yarn is twisted around itself and the force determined to pull

the yarn in contact with itself. Again, with a knowledge of the incoming

tension, the angle of wrap, and the outgoing tension, the frictional coefficient

can be determined. In the case of fiber to fiber friction, it is customary to

distinguish between static and dynamic frictional coefficients. Static friction is

determined at a low speed (on the order of 1 cm/min), and dynamic friction at

a higher speed. When measuring low speed friction, a stick-slip phenomenon

is sometimes observed. It is this measurement which is most closely related to the "scroop" observed with staple fibers, or the cohesion of staple fiber web

as it emerges from a card, or the performance of a finish composition in

yielding a yarn package which is stable and does not slough. The stick-slip

phenomenon indicates that the static friction is higher than the dynamic

friction and can be affected by the behavior of lubricants.

The lubricant composition of Example 1 containing a thioester

boundary lubricant additive, and a comparative composition without the

additive were applied onto nylon-6,6 fibers and tested to determine their effect

on friction. The results thereof are found in the Tables below.

Table 1 : Effect of Lubricant Composition on F/F Friction Based on Fiber

Pretension of 10 grams

As can be seen from the data in Table 1 , by adding the boundary lubricant

additive of the present invention to a textile lubricant composition, the fiber-fiber

friction, measured as a function of pretension, is effectively lowered.

Table 2: Effect of Lubricant Composition on S/S at 0.002 cm/s

As can be seen from the data in Table 2, by adding the boundary lubricant

additive of the present invention to a textile lubricant composition, the stick-slip

is effectively lowered at a coefficient of friction of 0.002 cm/s.

Table 3: Effect of Lubricant Composition on S/S at 0.5 cm/min

The lubricant composition may be applied onto the filament according to

a variety of known procedures. For example, in the melt spinning process used

for polypropylene manufacture, the polymer is melted and extruded through

spinnerette holes into filaments which are cooled and solidified in an air stream

or water bath. Shortly thereafter, they contact a lubricant composition applicator

which can be in the form of a kiss roll rotating in a trough. The amount of active

lubricant applied onto the filaments can be controlled by the concentration of

lubricant composition in the solution or emulsion and the total wet pick-up.

Alternatively, positive metering systems may be used which pump the lubricant composition to a ceramic slot which allows the lubricant composition to contact

the moving filaments.

From this point, the yarn which now has a coating of lubricant composition

moves forward into any of several processes. The amount of lubricant

composition to be applied onto a synthetic filament is also dependent on the end

product of the filament yarn. If staple fiber is the desired product, the filament

bundles are combined into large tows, oriented by stretching, crimped, and cut

into short lengths for processing on textile equipment to ultimately make yarn or

nonwoven webs. In this instance, it is the "scroop" of the fibers which is

intended to be enhanced. In order to do so, it is preferred the lubricant

composition have a concentration in the range of from about 0.5 to about 1.0%

OWF, based on percent actives. If continuous filament yarn is the desired

product, the filaments are also oriented but as discrete bundles containing a

specific number of filaments and are wound as long continuous lengths.

In one version the unoriented or undrawn yarn is wound on a package,

and drawn on a drawtwister. In another version called spin draw, the drawing

operation is carried out in a continuous fashion on the same equipment without

the step of winding the undrawn yarn.

Texturized yarns are also made as continuous filament yarns. Again,

texturized yarns can be made by texturizing a fully oriented yarn or by

simultaneously orienting and texturizing a partially oriented yarn.

In some of these processes the original textile lubricant composition

application carries the fibers through the entire process. In others, supplementary or overfinishes are applied somewhere later in the process.

The effect of frictional and static properties is generally obvious

throughout fiber manufacture and processing. Fiber to fiber friction is important

to the fiber producer in controlling formation and stability of filament yarn

packages since sloughing can occur if it is too low. Also, if fiber to fiber friction

is too low, there could be problems of poor web cohesion in carding of staple

fibers. On the other hand, low fiber to fiber friction is very desirable for

continuous filament yarns which are used in applications such as cordage which

involves twisting and plying. Low friction is desirable since it is associated with

high flex resistance and high energy absorption and therefore, long life. Fiber

to metal friction is also very important in many of the fiber processes. Lower

fiber to metal friction is generally preferred since there is less opportunity for

damage to the fibers either by abrasion or heat generation as the yarn contacts

metal surfaces.

Claims

What is claimed is:

1. A textile fiber finish composition comprising:

(a) from about 95 to about 99% by weight of a lubricant component; and

(b) from about 1 to about 5% by weight of a boundary lubricant additive

having the formula I:

R₁-OOCCH₂CH₂-S-CH₂CH₂COO-R₂ (I)

wherein R₁ and R₂ are each, independently, a C₈-C₁₈ alkyl group, all weights

being based on the weight of the composition.

2. The composition of claim 1 wherein the lubricant component is selected

from the group consisting of C₈.₂₂ fatty acids, synthetic hydrocarbon oils, alkyl

esters, polyols, polyol esters, emulsifiers, antistatic agents and mixtures thereof.

3. The composition of claim 1 wherein the lubricant component is present

in the composition in an amount of from about 98 to about 99% by weight, based

on the weight of the composition.

4. The composition of claim 1 wherein the boundary lubricant additive is a

diisotridecylthiodipropionate.

5. The composition of claim 1 wherein the boundary lubricant additive is

present in the composition in an amount of from about 1 to about 2% by weight,

based on the weight of the composition.

6. The composition of claim 1 further comprising a component selected from

the group consisting of a wetting agent, an antioxidant, a biocide, an anti-

corrosion agent, a pH control agent, and mixtures thereof.

7. A process for lubricating textile fibers comprising contacting the textile

fibers with a fiber finish composition comprising:

(a) from about 95 to about 99% by weight of a lubricant component; and

(b) from about 1 to about 5% by weight of a boundary lubricant additive

having the formula I:

RrOOCCH.CH.-S-C^C^COO-R, (I)

wherein R-, and R₂ are each, independently, a C₈-C₁₈ alkyl group, all weights

being based on the weight of the composition.

8. The process of claim 7 wherein the fiber finish composition is in the form

of an aqueous emulsion.

9. The process of claim 7 wherein the lubricant component is selected from

the group consisting of C₈.₂₂ fatty acids, synthetic hydrocarbon oils, alkyl esters,

polyols, polyol esters, emulsifiers, antistatic agents and mixtures thereof.

10. The process of claim 7 wherein the lubricant component is present in the

composition in an amount of from about 98 to about 99% by weight, based on

the weight of the composition.

11. The process of claim 7 wherein the boundary lubricant additive is a

diisotridecylthiodipropionate.

12. The process of claim 7 wherein the boundary lubricant additive is present

in the composition in an amount of from about 1 to about 2% by weight, based

on the weight of the composition.

13. The process of claim 7 wherein the textile fibers are contacted with from

about 0.3 to about 2.0% OWF of the textile lubricant composition.

14. The process of claim 8 wherein the fiber finish composition is present in

the aqueous emulsion at a percent actives concentration ranging from about 2

to about 20% actives.

15. The process of claim 7 wherein the fiber finish composition further

comprises a component selected from the group consisting of a wetting agent,

an antioxidant, a biocide, an anti-corrosion agent, a pH control agent, and

mixtures thereof.