DE2303328A1 - NON-WOVEN PANEL - Google Patents

Description

EIKENBERG & BRÜMMERSTEDT PATENT LAWYERS IN HANOVER

Eimberly-Clark Corporation 240/562

liichtgewette Bahn

The invention relates to a nonwoven web from continuous, randomly separated threads.

Iliohtwoven panels of continuous, random Separate, molecularly oriented threads made of a thermoplastic polymer are known.

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There are numerous methods of making such webs, but usually at least have three characteristics in common. First is this procedure a thermoplastic polymer (either from a melt or a solution) continuously extruded through a spinneret to produce discrete filaments; form. Then the threads stretched (either mechanically or pneumatically) to molecularly orient them and achieve good tenacity. Finally, the threads are deposited in a largely arbitrary manner on a carrier tape or the like in order to to produce a web with largely isotropic physical properties.

The processes described above

The thread webs provided are characterized by a typical fabric-like softness, suppleness and drapability and are therefore often well usable where the usual woven fabrics are otherwise used. In their raw state, however, such webs are usually very unstable and lack the strength required to enable them to be used successfully in numerous applications such as: B. in bed linen, clothing, curtain material, etc. would allow. It is therefore common practice to stabilize such webs formed from continuous threads by joining the threads contained in the web either directly or with the aid of supplied adhesives.

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Many of the known bonding methods increase the j

Stability of the railways, but problems often remain open, j

when stability is desired in conjunction with other j

Properties such as cloth-like drapability, softness j

Vina handle should be achieved. Procedures in which the j

"Threads in the web at largely all intersection points j

connected, result in a product that is hard and stiff ! is, and although the initially hard and stiff handle

from excessively bonded webs often wears off when the j

Orbit is in use, the observed decrease occurs |

stiffness and hardness usually not in such a '

Measure to make the track aesthetically pleasing, it is >

because that a very light overall network is provided. !

On the other hand, a light overall network is undesirable: as it is then difficult to obtain the required strength and

To achieve resistance to surface wear. _;

Considerable efforts have been made to ^{achieve 1 the} desired pestibility properties in connection with fabric-like drapability, softness and hand; testify, however, the fabric-like properties are only at
Use is desirable, while their presence prior to use can be detrimental. For example, if
a web is quilted onto another material, that is
Presence of a textile-like quality in the quilting process is undesirable. Hen the use of a textilähnlic

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soft, slack web makes quilting difficult, as the web tends to pucker when it goes through the quilting machine is running, and therefore when used in this way, the Track a stiffness that is useful for good function is desired. On the other hand, the stiffness should be temporary, there the end product should be fabric-like and soft when used in the intended environment. It should be noted that the use of excessively stiff materials is also undesirable because such materials are reversed reduces the quality of quilted products and additionally leads to an end product that is stiff to the touch.

The need to use stiffer Materials used in textile processing, such as Steppes, of course, has long been recognized. Accordingly, it is common to use textile materials with starch or the like to be finished in order to make them sufficiently stiff for processing in quilted clothing. The finish is generally removed from the quilted material after the first wash or gradually during use, and thereby the result that can be ascertained by buyers of customary textile products Increase in softness. Finishing, however, has the disadvantage that it is an additional process step means.

The invention is based on the object of a nonwoven web of continuous, randomly discontinued

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To create threads that inherently like the properties after a treatment with a finish ", which, however, becomes strong after mechanical stress or normal use are reduced, so that the result is a textile-like Material with the desired drapability, softness and grip is created.

The object set is achieved according to the invention in that a plurality of discrete, compacted Zones are provided in which a relatively strong autogenous composite of the threads is present that the zones in an interrupted pattern over the surface of the web are distributed to give the web strength and resistance to surface wear and that the threads in the areas between the compacted zones at intersections are also in an autogenous bond, the weaker is than the composite in the compacted zones, 80 of the web has a greater initial stiffness and properties to give a finished web.

The surfaces of the compacted zones show a film-like appearance and when viewed under a microscope will have the presence of a comprehensive one Fusion between the threads and the loss of thread identity apparently. Since the intensity of the composite in the Areas between the twisted zones is smaller, the threads retain their individual configuration at the connection points, and the junctions are at meohanisoher;

Easy to separate again. Such tracks are sufficiently stiff for processing, however take they give a soft and drapable structure after they have been finally put into use, with their Strength is retained.

The webs can be continuous threads made of polypropylene, but they can also be made of other threads as well Spinnable thermoplastic polymers are made that have identifiable crystalline melting points that allow a suitable choice of bonding conditions under which the combination of different composite intensities explained below can be generated. Except Polypropylene can include other polymers as well Polyethylene, polyamides and esters such as polyethylene terephthalate and mixtures of thermoplastic polymers and / or polymers can be used.

The invention is explained in more detail below with reference to the drawing. In the words:

Fig. 1 is a schematic side view

an apparatus for producing one designed according to the invention Train and

Fig. 2 shows a representation of the surface area

see a j produced according to FIG Train. I.

123

According to Pig. 1 is a polymer 10 into a;

usual extruder 12 introduced, and in the form of threads 14 I

extruded through a spinneret 16. When going through an i

subsequent take-off device 18 are the spun ι

Threads 14 stretched. Then the threads in optional I

loose arrangement, a moving carrier 20 ab- j

sets and forms a web 22 thereon. The formation of a web on the carrier can be assisted by suction means 24 i .

With regard to the embodiment of the invention;

is the uiid way in which the web 22 is formed ^!

not of particular importance, and anyone can do this!

any technique can be used. With a suitable!

Processes continuous threads from a synthetic> polymer are spun in a generous way, for example by ^; that the polymer is extruded through a plurality of downwardly directed spinnerets, which are preferably in a or j

several rows are arranged. The threads are spun
then into a straight line of untwisted bundles;

at the same distance, with each bundle at least 15
and preferably contains between 50 up to 1,000 threads. These thread bundles are simultaneously and preferably at a speed of at least 3,000 m / min
from 3 500 to 8 000 m / min in individually surrounding:

Columns of gas drawn down, flowing at supersonic speeds and directed so that they hit you
approximately horizontal beam takes place. The gathering of the threads'

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untwisted bundles, stretching and striking the carrier is preferably provided by sliding the bundle through it by air cannons "causes the threads with a column or surrounded by a stream of air traveling at supersonic speeds is directed downwards. The air cannons are arranged so that they are in one or more rows extend transversely to the carrier at right angles to its direction of movement, whereby the trapped in the gas columns Bundle when hitting the moving carrier in a line or row at right angles across the Extend carrier. In order to facilitate the enforcement of the bundle, they can be made to vibrate, the plane of the vibrations running transversely to the direction of movement of the wearer. A carrier that is customary in the production of non-woven webs can be used as the carrier, for example an endless belt screen or the upper part of a drum, for example a sieve drum.

The thread bundles, which contain a number of parallel threads, are looped onto the carrier Deposed arrangement, with primary soles extending front to back over a width that extends through the impact of the air column from one of the air cannons the carrier is intended. Before and when the parallel ones meet Thread bundles on the carrier these are split into sub-bundles, which contain fewer parallel threads and form secondary smaller loops and vortices. the secondary loops and vertebrae overlap each other and also

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the loops in adjacent sections so that as a result an almost complete penetration takes place with the overlapping parts of the neighboring areas. Form thereby the separated thread bundles a continuous uniform, nonwoven web.

The web, after being formed on the carrier 20, becomes slight as it passes between rollers 26 and 28 compacted, a low level of solidification and a sufficient one Cohesion for further processing too create. In addition, a very light thread composite can be used the surface of intersection spunk te η through this solidification step caused, although the extent of the bond is not intense enough at this point to make a noteworthy To create stabilization or stiffening of the web because the threads are cold. As a result, after solidification the web 22 after passing a deflection roller 38 in contact brought with a hard smooth heating roller 30. Afterward the web runs through a nip which the roller 30 forms with a hard hot roller 32 resting on its surface has several raised spots. After leaving the gap, the web remains in forced ■ contact with the roller until it is removed via a second deflection roller 40. j

The surface of a web previously produced using the manner described in FIG. 1 is shown in FIG. 2, the compacted zones 36 in which the threads 34 are atarkic autogenous! are connected to each other, have a film-like appearance due to the extensive fusion of the threads. This merger is

*, .τ η Λ '■) A. * Λ -i *

particularly visible on the surface side, which is shown in Has been in contact with the roller 32. The compacted zones are due to the raised areas on the roller 32 when the web passed through the gap formed by the rollers 30 and 32. The intensity of the thread bond in the compacted zones in connection with their distribution and size essentially causes the strength properties the web as well as its possible drapability, softness and its textile-like feel.

The areas 38 'between the densified zones still show the thread structure, because there is no complete thread fusion. However, it is a slightly autogenic one • Network at many intersection points in the areas 30 ' available. The number of these connections and their intensity contribute to the desire for an initial te if ity of the path at.

After the above general discussion of the invention, it should be noted that in order to obtain a combination of different composite strengths which are to lead to the results sought by the invention, a careful selection of the conditions in the machine must be made. Ia this context is the temperature of the rolls 30 and 32, the Varweilzeit during which the web 22 in contact with the orphan ¹ 30, the pattern of raised areas on the! False 32 as well as the amount and the Andruok of importance.

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The selection of the appropriate conditions is based on the following Considerations:

The residence time of the web on roller 30 and in particular the time before the nip is to be coordinated with the temperature of the rollers 30 and 32 so that the threads on the web surface reach a temperature which is below their crystalline melting point, but is sufficiently high to soften the threads and thereby create the possibility of them at their crossing points to be cohesively bonded together when the web is subjected to light pressure. As mentioned before, These connections seem to contribute to the railway Maintains properties of a finished web. Duroh coordination of dwell time and roller temperatures can The connections are formed with an intensity and in a number that provide adequate rigidity in the web is built in, which is required for processing in quilting machines and the like, and yet the Connections are then easily destroyed again, so that they do not lose their softness and drapability Affect use. As explained below residence time and temperature are also important to achieve this the desired strength properties of the web.

Choosing a suitable pattern for the sublime Place on the roller 32 is important in order to achieve the strength of the web without the textile-like properties

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i I stocks that the railway develops in use, naoh- ι

I partly influence. The pattern of the raised spots;

ι on the roller 32 should be chosen so that the path!

• 2 I j has about 100 to 500 compacted zones per 6.5 cm, \

i where the zones total about 10 to 25 % of the web area
; take in. If more densified zones are provided, then 'j ^; can the web no longer in use the desired draping · ^; develop ability and softness. A large number of

• sealed zones also makes it difficult to achieve a light ^! Thread connection in the areas between the compacted zones. In the same way, the textile-like properties

S abort the web when the compacted zones have a>

; Share of 25 ° f exceed the total, and in particular

It becomes special when the number of densified zones increases

i getting harder to get the required degree of different

! To achieve Yerbund intensity in the web. To be adequate

! Achieving web strength is a number of at least

[' 100 / 6.5 cm with a share of $ 10 of the total web area
necessary.

In connection with the aforementioned bond conditions is that of the raised areas in the gap between the. Rollers 30 and 32 exerted pressure and the height of the raised
Places of importance. The pressure at the raised areas ' must be so great that the threads in the compacted zones'

are intensively connected, and thus a good web strength and a resistance to surface wear |

is achieved even with repeated use of the web. About that

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In addition, the Druok can be an important variable if placed high demands on the energy absorption of the railway will.

The height of the raised areas on roller 32 should be smaller than the thickness of the web entering the nip, so that the surfaces of the web when Passing through the gap are in contact with the heating rollers. This dimensioning is important in order to achieve the above-mentioned light thread bond between the twisted zones reach. If the raised areas are significantly larger than the web thickness, the areas between these j

Do not put pressure, and consequently the threads come in ^!

these areas are also not in sufficient contact to bring about the bond that is necessary for the finishing properties to achieve. j

On the other hand, the raised areas in the

Compared to the web thickness, it must be sufficiently high to ensure len that the pressure applied to the web in the nip did- i

Plural on the locations of the web is limited, the \ with the raised dots come into contact and the pressure \ is not distributed to the entire web surface. This is important in order to achieve a good tensile strength and to avoid an excessively intensive connection in the web areas located between the twisted zones, because the web would then not become soft in use. For the same reasons, it is desirable to give rollers 30 and 32 a hard /

'-M-; 33

To give surface, as this results in high specific pressures, in particular can be achieved in the railway areas that come into contact with the raised areas. It also allows the use of hard rollers made of steel or the like an independently regulated heating and causes a good heat transfer.

Ea is desirable that the raised points on the "roller 32 extend as possible vertically, that is, the sides of the bodies are mutually-parallel, although the edges are slightly _(rounded to avoid severance of the thread. When extending vertically In the areas of the web that come into contact with the upper side of the raised areas, an intensive bond is created in the areas immediately adjacent to the densified zones _; directly next to the compacted zones, contribute to the fact that the;

Railway receives the desired initial stiffness.

The invention is particularly suitable for use in webs of continuous threads with a basis weight between about 31 g / m ^a and 93 g / m * with a denier of the threads between about 0.5 to 10. The small thickness of webs with a lower basis weight makes it difficult to achieve the different composite intensities that are required ■ * vtm a product with the properties of a;

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To produce a finish that becomes soft in use but still remains firm. With higher base weights, this is Application of the invention also limited as the webs then they are very stiff, even if they are only intermittent Exhibit composite. In addition, with high basis weight webs, it is difficult to obtain a localized high To generate pressure at the points of the web that are in contact with the raised points, because then it is hardly to avoid that the pressure on the entire web surface distributed. The invention is best suited for webs having a basis weight between about 34 grams per square meter

62 g / m and deniers of the threads between about 0.8 and 2.5

Leave the required compound conditions can easily be determined experimentally for a given trajectory using the guidelines given above. For railways, which contain polypropylene fibers and a basis weight of

ο ο

less than 77 g / nT and especially less than 62 g / m

; Have temperatures of rollers 30 and 32 of about; 143 to 175 ^° C. or 138 to 165 ^° C. useful with a pressure exerted by the raised areas of about 560 to 1550 kg / cm and web speeds of about 10 to 70 m / min _; . Lower web speeds and higher pressure pressures and roller temperatures in the specified ranges should only be used in conjunction with webs with a higher basis weight. In connection with these composite conditions, the raised points on the roller Ϊ2 preferably have a height of about 0.25 to 0.75 mm, and the ) _{ j

! ■ I

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Deflection roller 38 is arranged with respect to the gap between rollers 30 and 32 so that the wrap around roller 30 in front of the gap is approximately 15 to 35 ° . Furthermore, the wrap around the roller 30 behind the gap is preferably just as large as in front of the gap.

Sheets made in the manner described have (1.) a cantilever stiffness of at least about 2.8 cm, and preferably at least about 3.3 cm, (2.) at least about 30% reduction in overhang stiffness length after a single wash cycle, and (3) A basis weight tensile strength of at least about 6, and preferably at least about. Sheets having these properties have been found to be useful in numerous applications where initial rigidity for processing and drapability, softness and strength in the subsequent process Use is required. Preferably, the webs are designed so that the decrease in overhang stiffness length after a wash cycle is at least about 35 % (decrease in overhang stiffness length to less than 3.8 cm) and, in connection therewith, only a small decrease in strength (e.g. less than about 20 $ and preferably less than $ 10) so that after a single wash cycle the webs have a basis weight tensile strength of at least about 5, and preferably at least about 6.5. Furthermore, the initial stiffness should not be so great that it has an overhang stiffness length of more than 6.3 cm and

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preferably no more than about 4.8 oi generated. Lanes with also have higher stiffness values " further disadvantages and cannot be quilted in such a way that a product is obtained in which a pronounced bulkiness present in the areas between the quilted parts is.

The decrease in rigidity after washing obviously stems from the fact that the light thread bond between the compacted zones is destroyed. The missing a significant decrease in strength during washing shows that the bond between the threads in the densified zones is sufficiently intense to withstand the washing process.

It has also been observed that in the

webs made according to the invention after washing a greater decrease in energy absorption than in tensile strength demonstrate. This observation confirms the presence of the combination of light and strong connections of the kind discussed above. The tensile strength of the web should, if at all, be little affected by the wash cycle because the size of the tensile strength is in principle due the strongest bond is created and by its presence not significantly influenced by weaker compounds will. Thus, the presence or absence of one is likely weak thread bond between the compacted zones the Do not noticeably impair the tensile strength of the web.

123

The energy absorption is on the other hand by everyone in the Web affects existing thread associations. If, therefore, the light associations between compacted zones in the Washing are destroyed, while the strong associations are largely preserved, it follows that the Energy absorption during washing is reduced more than the tensile strength. Indeed, they behave accordingly The invention made Uten railways in this way.

The test to determine the overhang stiffness mentioned is described in ASTM D-1388. This test is carried out in "which is a 2.5 µm wide strip of the web." is placed on a horizontal surface, one end of which is followed by a surface inclined by 41 * 5 °. The sample is then applied with its narrow edge to the connection of the horizontal and the inclined surface and over the Edge between the two surfaces pushed forward until the free end bends and the inclined one Touches surface. Half the length of the pattern between the starting point of the horizontal surface and the point of contact with the inclined surface is the overhang stiffness length » A greater length therefore means greater rigidity.

The tensile strength of the web is using a standard Instron testing machine on 2.5 cm "wide web samples using a 7t5 om gauge length and a Crosshead speed of 30om / min determined. The maximum Tensile strength value (Ibe / inch) divided by the base

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weight (ounces / yard before washing) is based on the basis weight related tensile strength. The energy absorption represents the area under the force-strain curve for determination the tensile strength and can be determined either by calculation or by using an automatic integrator will.

The mentioned values of the overhang stiffness length the tensile strength and energy absorption represent the average values in the machine and transverse directions the railway were obtained. Measurements were made on at least 5 samples in each direction.

The wash cycle used is in AATCC Test Method 88B "be s ore" be η and a standard model of a 600 ¹¹ KENMORE "1.8 kg wash load machine" was used. The wash took 10 minutes at 66 ° including a purge at 40 ⁰ C. Drying was carried out for about 7 minutes in a blower eta temperature of 50 to 70 ° long followed by five minutes cooling. 225 g of the detergent sold under the trade name “GAIN” by Proctor & Gamble were added to the laundry.

The examples below illustrate

The invention. Table I shows the properties of the webs.

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¹ ABELIE

example

Basis weight g / m web width (cm)
Denier of the thread thread tenacity (g / denier) thread elongation

Crystalline melting point of the threads ( ⁰ O)

31 46 74 137 137 137 1.6 1.8 1.77 3.5 5.0 3.0 130 159 141 141 141 141

The composite of the web was carried out with a gate direction according to FIG. Steel rollers 30 and 32 with a diameter of 38 cm provided with heating means were used. The raised areas on roller 32 were
about 0.43 mm high and arranged so that the treated web densified zones at regular intervals in the form of a

Diamond pattern with a density of about 200 such zones

ρ
per 6.25 cm. Each zone represented a square with

a side length of about 0.27 mm, the diagonal of which is in
Machine direction pointed. About $ 17.5 of the total area of the
The track was provided with compacted zones. The pulleys and 40 goods arranged so that a wrap of about 15 # was achieved before and after the nip. The conditions for the bond are shown in Table II.

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TABLE II

168 171 171 157 160 160 991 1160 Ίΐ60 41 25th 16

example

Temperature ( ⁰ C)
Roller 30
Roller 32

Pressure force kg / cm *
Web speed (m / min)

* In raised areas, calculated from the total load applied to the rollers, taking into account the roller weight and assuming the nip has four raised points in the machine direction.

Measured values of the webs produced under the aforementioned conditions are given in Table III:

TABEL example III i 65 2 , 6 3 Before washing 4th 1.6 Overhang strength
Length (cm) 3, 4th 4th , 75 6th tensile strenght
lbs / inch .6, 1 , 5 14.6 On the basis of be
tensile strength ** 6, 7th 6.1 Energy absorption (inch-lbs) > 1 2 3

Customs"

: · 0 i; ο 3 G / 1 1 ^Λ . 3

-22 port setting Table III

Example 1_ £ ■ J $

After a wash

Overhang stiffness 2.2 2.86 3.8

Length (cm)

Tensile strength 7.1 10.9 12

Lbs / inch

Tensile strength applied to basis weight 7.1 7.3 5 **

Energy absorption ( inch-pounds ) _Λ . _{oxo A}

ZoIl ^

Decrease in stiffness

length after washing 39 $ 38 $ 37 $

Decrease in the standardized

Firmness after washing no $ 5.8 $ 16.5

Decrease in energy

absorption no 8 $ 20 $

* Surface area equal to 3 square inches

** maximum tensile strength value divided into (lbs / inch) by the basis weight (ounces / yard)

The webs produced in the above manner meet all the requirements placed on them, in particular the web produced according to Example II is to be preferred. Besides the aforementioned and desirable properties are the webs produced in the manner described above duroh a three-dimensional appearance on both sides

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marked what the presence of the compacted Zones and the only lightly connected threads between these zones is attributable.

In the webs described, the extent of the fiber composite is in contact with the roller 30 in the gap coming web side a little lower. This seems to be an advantage when such webs are quilted as cover material with the less intensely glued side of the web in intimate contact with the fluffy wadding that is being used often found in such applications. When using can the wadding fibers intertwine with the fibers on the web surface, so that if necessary. The area between quilted Parts are given a desired level of stability.

-Patent claims-

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Claims (11)

Claims 1 . Nonwoven web made of continuous, randomly discontinued Threads, characterized in that a large number of discrete, compacted zones are provided in which there is a relatively strong autogenous bond of the threads is that the zones are distributed in an interrupted pattern over the surfaces of the web to give the web strength and to impart resistance to surface wear, and that the threads in the areas between the compacted zones at intersection points are also in an autogenous bond stand, which is weaker than the bond in the compacted zones, so that the web has a greater initial strength and to impart the properties of a finished web. 2. Nonwoven web according to claim 1, characterized in that that these have a basis weight of about 31 g / m to 93 g / m 2 2 and preferably from about 34 g / m to 62 g / m. 3. Uichtwebte web according to claim 1 or 2, characterized marked that the filaments are molecularly oriented and consist of a thermoplastic polymer having a denier of about 0.5 to 10 and preferably of about 0.8 to 2.5. 309830/1123 4. Nonwoven web according to claim 3, characterized in that the thermoplastic polymer is polypropylene. 5. Nonwoven web according to one of the preceding claims, characterized in that the compacted zones over ό The web is distributed in an amount of about 100 to 500 per 6.25 cm and occupies an area of about 10 to 25 % of the total area of the web. 6. Nonwoven web according to one of the preceding claims, characterized in that the stronger composite is dimensioned so that it withstands a washing process, and that the weaker composite is dimensioned so that it is destroyed in a washing process. 7. Nonwoven web according to claim 1, characterized in that the base weight between about 31 g / m and 93 g / m, the denier of the threads between about 0.5 and 10, the number of densified zones between about 100 and 500 per 6 , 25 cm with an occupancy of the total area of the web of about 10 to 25 #, and that the overhang stiffness is at least 2.85 cm, the tensile strength related to the base weight at least about 6 and the decrease in the overhang stiffness after a washing process at least 30 $ amounts to. 8. Nonwoven web according to claim 7 » characterized in that that she owns t. P P that they have a base weight between about 34 g / m to 62 g / m 309830/1 1 23 9. The nonwoven web of claim 7 or 8 characterized in that the filaments have a denier of about 0.8 to 2.5. 10. Mchtgewebte web according to claim 9 » characterized in that the thermoplastic polymer is propylene. 11. Mchtweate web according to claim 1, characterized in that it has a basis weight between about 31 g / m and 93 g / m and a denier between about 0.5 and 10, that the distribution of the densified zones and the intensity of the composite therein is dimensioned so that the web has a basis weight tensile strength of at least about 6 and an overhang stiffness length after a wash cycle of less than about 3.8 cm and that the intensity of the bond between the pad intersections between the densified zones and the number of bonds is dimensioned so that the. Web has a stiffness overhang length of at least about 2.85 om owns and the decrease in the overhang casting igke it after a washing process at least $ 30> is. 309830/1123