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Title:
A SPUNBOND NONWOVEN FRONTAL TAPE
Document Type and Number:
WIPO Patent Application WO/2019/132789
Kind Code:
A1
Abstract:
A frontal tape having multilayer spunbond structure and its manufacturing process is provided. Said spunbond layers have different fiber deniers which enable an improved attachment and peel, shear and delamination behaviour. Frontal tape of the present invention is prepared by a one step simple process of melt extrusion, spunbond and hot calendering using polypropylene as a cheap raw material source.

Inventors:
ERGUNEY FATIH (TR)
DOGAN SEBNEM (TR)
Application Number:
PCT/TR2017/050701
Publication Date:
July 04, 2019
Filing Date:
December 27, 2017
Export Citation:
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Assignee:
HAYAT KIMYA SANAYI ANONIM SIRKETI (TR)
International Classes:
D04H3/007; A44B18/00; A61F13/62; B32B5/02; B32B5/26; D04H3/14; D04H11/08
Domestic Patent References:
WO2009021473A12009-02-19
Foreign References:
US20140127461A12014-05-08
EP3187635A12017-07-05
US20030077430A12003-04-24
EP2540272A12013-01-02
US7789870B22010-09-07
US9744085B22017-08-29
Attorney, Agent or Firm:
OZTURK FILIZ, Filiz (Altunızade, Uskudar/Istanbul, TR)
Download PDF:
Claims:
CLAIMS

1 A spunbond nonwoven web suitable as loop component of a hook and loop fastening system wherein said spunbond nonwoven web is embossed and comprises substantially continuous monofilament polypropylene fibers characterized in that said spunbond nonwoven web comprises spunbond-spunbond-spunbond (SSS) fiber layers comprising an upper spunbond layer, a middle spunbond layer and a bottom spunbond layer,

wherein each spunbond fiber layer has different fiber denier,

wherein the upper layer is the layer designated for bonding with said hook

2 A spunbond nonwoven web according to claim 1 , wherein the upper spunbond layer has 2.2 to 3.0 , preferably 2.5 to 2.8 fiber denier.

3 A spunbond nonwoven web according to claim 1 , wherein the middle spunbond layer has 1 ,5 to 2.5, preferably 1.8 to 2.2 fiber denier.

4 A spunbond nonwoven web according to claim 1 , wherein the bottom spunbond layer has 1.5 to 2.2 , preferably 1.5 to 1.8 fiber denier.

5 A spunbond nonwoven web according to claim 1 , wherein said spunbond nonwoven web further comprises 0.2 - 2.0 % of Ti02 by weight as an additive.

6 A spunbond nonwoven web according to claim 1 , wherein said fiber layers are bonded together thermally or mechanically, preferably thermally with calender having emboss roll.

7 A spunbond nonwoven web according to claim 1 and claim 6, wherein said emboss roll has figures of continuously repeating design pattern.

8 A spunbond nonwoven web according to claim 1 and claim 6, wherein said spunbond nonwoven web has an embossed area of between %10 to % 45, preferably %20 to % 35 of the total nonwoven web area.

9 A spunbond nonwoven web according to claim 1 , wherein each said spunbond fiber layer has a weight per area of 7 to 25 g/m2 respectively.

10 A spunbond nonwoven web according to claim 1 and claim 9, wherein said spunbond nonwoven web has a weight per area of between 20 to 75 g/m2, preferably between 30 to 45 g/m2.

11- A process for producing a spunbond nonwoven web according to claim 1 , comprising the steps; - melting of polypropylene in the first, second and third extruders , followed by spinning by spinnerets to produce first, second and third filament fibers having different deniers,

- laying said spinned filaments on a moving conveyor belt having at least 2000 rpm suction belt speed,

- thermally bonding of said oriented fibers between two hot calenders wherein, the temperature difference between the calenders is up to 15 oC.

12 A process for producing a spunbond nonwoven web according to claim 1 1 , comprising the steps;

- melting of polypropylene in the first extruder , followed by spinning by spinnerets to produce the first filament of 2.5 to 2.8 fiber denier thickness,

- melting of polypropylene in the second extruder a followed by spinning by spinnerets to produce the second filament of 1.8 to 2.2 fiber denier thickness,

- melting of polypropylene in the third extruder followed by spinning by spinnerets to produce the third filament of 1.5 to 1.8 fiber denier thickness,

- laying the first, second and third filaments subsequently as layers continuously on the conveyor belt having 2000 to 2400 rpm belt speed,

- thermally bonding of said filaments between two hot calenders wherein the tempretarure difference between the calenders is up to 5 oC, wherein preferably the upper calender tempretarure is set at around 176 oC and the lower calender tempretarure is set at around 180 oC, to obtain said spunbond nonwoven web

13 A spunbond nonwoven web suitable as loop component of a hook and loop fastening system according to preceeding claims wherein, said nonwoven web can be used as a fastening member of disposable diapers and refastenable pants or pull ups.

Description:
A SPUNBOND NONWOVEN FRONTAL TAPE

TECHNICAL FIELD

The present invention discloses a spunbond nonwoven frontal tape for a diaper comprising an unbonded region, wherein the fibers in the unbonded zone are fluffy, and a bonded zone which enhances the mechanical strength and delamination strength of the spun layers. The specially designed frontal tape, which is produced by spunbond technology, and bonded by calender, makes the baby feel more comfortable, and is durable with a certain emboss area. The production process of present invention material is a one step process being more simple and economically advantageously

BACKGROUND ART

The present invention relates to a spunbond nonwoven frontal tape, more particularly to a nonwoven web located on front waist of a diaper for attaching hook .

Nonwoven web is produced by a variety of known processes other than weaving or knitting.

Nonwoven web is used in various applications such as; automotive industry, disposable and medical applications, hygiene products; diapers, incontinence pads, feminine hygiene articles or nappies.

The nonwoven web properties depend to a great extent, on following factors;

- the choice of raw material with that the nonwoven web is produced,

- the production technology which forms the nonwoven web,

-- the bonding process which consolidates the web to gain mechanical strength compared to its unbonded form,

- the parameters of nonwoven production processes are such as; pattern of emboss structures applied on the nonwoven web structure; suction to move the filaments to form the nonwoven web on the web forming belt; conditions of emboss application of emboss roll and pressure roll on the nonwoven web surface.

- The emboss patterns mainly affect the properties of the produced nonwoven fabric such as, softness, strength, elongation and especially peel, shear properties. - The parameter suction has an important role to obtain optimum fiber orientation and opacity of nonwoven web.

- The current technology of the production method of frontal tape is Extrusion Bonded Laminate; EBL that comprises a multi-layer coextruded elastomeric film and a nonwoven web. However, this method is a two step and time consuming process. Additionally, the products produced with EBL process is not recyclable due to mixing of two or more type of polymers such as polypropylene and polyethylene.

- The fiber denier is an important factor on the softness and peel, shear performance of nonwoven web.

- There exist trials to obtain fluffy surfaces to improve peel, shear performance by inhibiting delamination of nonwoven fabrics at the same time.

In the hook and loop fastening system attachment strength and resistance specifically to shearing is necessary. The loop components has been provided in the state of technic such as;

EP2540272 is about a multilayer landing zone for diapers which comprise a first layer of a film, a second layer of nonwoven, bound together with a glue. Therewith a robust attachment area for hook part is provided. However having two layers of material and bonding them together with a glue makes this type of frontal tape economically not feasible.

US7789870 whereas composite fibers having different type of polypropylene are produced by melting and exiting from spinnnerets and cooling to form curly, crimped fibers to form loop by further processing of thermal embossing. These crimped structured loop has a voluminous and curly structure to attach the hook to loop component. But, handling with crimped fibers in general and forming a landing zone therewith is a technically and accordingly financially a challenging issue. Besides, these type of loops lacks especially of integrity, since bonding of crimped fibers by thermal embossing leads to a structure which is prone to disintegration and weak attachment by hook and loop application.

US9744085 is about a fastening system comprising multicomponent fibers of polyolefine and polyamide type. This type of loop component has satisfactorily mechanical capabilities such as at fastening and holding. However the use of multiple component polymeric fibers enhance the production costs in addition to recovery problem. In most cases the separation of different polymeric fibers is not possible. The present invention overcomes above mentioned problems. In the present invention mechanically and physically improved nonwoven fabrics are produced. Nonwoven fabrics that have fluffy structure and improved resistance to delamination are obtained without losing the peel and shear force of the nonwoven web. Additionally, use of light weight fibers, faster line speed and simplified process makes the present application cost effective.

SUMMARY OF INVENTION

The present invention provides a spunbond nonwoven frontal tape (1 ) formed from continuous thermoplastic filaments made of polypropylene fibers, specially substantially amounts of polypropylene fibers, having a multi-layer spunbon-spunbond-spunbond (S-S- S) nonwoven layer combination having different fiber deniers in each layer respectively.

The spunbond nonwoven frontal tape according to the present invention has multi functional nonwoven layers; an upper layer providing optimum delamination and peel, shear performance; a middle layer supporting peel of hook and air permeability; and a bottom layer inhibiting air permeability to optimize processability of vacuum system of the baby diaper machine. Thus obtained materials can be used for disposable products such as diapers, sanitary napkins or any kinds of hygiene products.

The process for the preparation of said materials comprises the spunbond method with following steps;

- feeding polymer and additives to the extruder,

- extruding polymer and additives as master batch,

- spinning of fibers,

- drawing and deposition of fibers,

- web formation of fibers,

- thermal bonding of fibers,

- winding. In the present invention, physical and mechanical performance parameters of spunbond nonwoven frontal tape, such as; peel and shear force, air permeability, delamination/peel force, can be improved by optimizing spunbond process parameters.

Applying appropriate process condition with suitable raw material is the critical goal of obtaining good peel and shear performance without delamination or pilling. Furthermore, the technology of the present invention is comparatively cost effective by optimizing material performance with only process parameter changes compared to the common multi-step production technology.

Nonwoven fabrics, typified by spunbond or melt blown nonwoven fabrics are usually partially thermobonded via an embossing roll in order to prevent the falling-off of fibers which form the nonwoven fabric and by this way to improve the strength of the fabric.

In the present invention spunbond webs are bonded by thermal bonding by using emboss roll. Emboss roll with continuously repeating designed pattern is used to obtain embossed patterns on nonwoven web, thereby a strong nonwoven fabric is obtained.

In the present invention an improved embossing design is applied on a spunbond nonwoven frontal tape. Said embossing design pattern may be concerning of geometric structures of endless wavy shaped form.

The spunbond production has a high production volume, but a limited application field. In the present invention, spunbond nonwoven acquieres new performance features and new application field.

The spunbond nonwoven frontal tape having multi denier fiber layers gives excellent material performance, such as; peel, shear force, air permeability, deformation and delamination.

The spunbond nonwoven frontal tape that is formed by continuous monofilament polypropylene has higher mechanical strength than the frontal tapes formed with common methods.

The production of present invention materials comprises of is one step process that is more simple and has practical value than common technology which has an extra film lamination step. FIGURES

FIG. 1. Spunbond-Spunbond-Spunbond SSS multilayer nonwoven web according to present invention

FIG. 2. Embossed nonwoven web

FIG. 3. Schematic preparation of SSS trilayer nonwoven web

FIG. 4. Embossing process of nonwoven web

FIG. 5. Peel test mechanism

FIG. 6. Shear test mechanism wherein;

1 : Upper spunbond layer

2: Middle spunbond layer

3: Bottom spunbond layer

4: Diaper

5: Embossed area

6: Nonembossed area

7: Conveyer belt

8: Pressure roll

9: Emboss roll

10: Nonwoven web

11 : Hook sample

12: Loop sample

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a spunbond nonwoven frontal tape (1) that is suitable as loop component of a hook and loop fastening system comprising spunbond-spunbond- spunbond (SSS) fiber layers, wherein each spunbond fiber layer has different fiber denier. The materials of the present invention can be used for disposable products such as diapers, sanitary napkins or any kinds of hygiene products.

The present invention provides a spunbond nonwoven frontal tape formed from continuous thermoplastic filaments made of polypropylene, preferably polypropylene fibers in substantial amounts having a multi-layer nonwoven layer combination having 2.2-3.0, 1.5- 2.5, 1.5-2.2 fiber denier of the respective nonwoven layers. The spunbond fiber layers to 25 g/m2 unit weight for each layer.

The spunbond nonwoven frontal tape of the present invention has multi-functional nonwoven layers of; an upper spunbond layer having improved delamination , peel and shear performance; a middle spunbond layer supporting peel of hook and air permeability; a bottom spunbond layer inhibiting air permeability to improve handling with vacuum system of diaper production machinery.

The spunbond nonwoven frontal tape having multi denier fiber layers gives excellent material performance.

Furthermore, the denier of the fibers of the bottom spunbond layer of the present invention is reduced to between 1.5 -1.8 which enables reducing air permeability during processing better.

In order to further improve the loop fastening performance and air permeability, the denier of the middle spunbond layer fibers is kept between 2.5-2.8.

In order to further improve the peel and shear performance of hook and loop system as well as delamination of the layers, the denier of the upper spunbond layer fibers is kept between 2.2-3.0.

In order to further make the expected performance of the hook and loop system more reliable, the unit weight of the spunbond nonwoven frontal tape is kept in between 20 to 75 g/m2 , preferably 30 to 45 g/m2.

In order to further decrease the delamination risk of multilayer structure of the spunbond nonwoven web , the spunbond nonwoven frontal tape has a unit weight lower than 75 g/m2.

In order to further improve the peel and shear performance of the spunbond nonwoven web material, the spunbond nonwoven frontal tape has a unit weight higher than 20 g/m2 , to create enough material volume for attachment of hook.

The present invention provides production of a spunbond nonwoven web with means of thermal bonding by application with hot calender. Said calender comprises of two rolls; an emboss roll and a pressure roll. The emboss roll is used as hot calender which has specific endless wavy design pattern to obtain embossed patterns on nonwoven web. By this way, a strong nonwoven web is obtained. The spunbond nonwoven frontal tape of the present invention has an emboss area of 10% to 45%, preferably 24% to 30%.

In a further embodiment, the nonwoven web having embossed structures which can have figures of continuously repeating designed pattern. The design pattern of emboss may comprise 2-10 figures/cm2, preferably 5-6 figures/cm 2 . This enhances bulkiness of nonwoven web and provides excellent peel and shear performance. The emboss structure obtained as such has 0% to 4% pitch angle.

The present invention further discloses;

In one embodiment, formed spunbond nonwoven web fibers having the diameter of fiber forming the nonwoven fabric is in the range of 1.5-3.0 denier are obtained by adjusting the line speed in the range of 150 - 650 m/min. When the line speed is more than 650 m/min low weighted nonwoven webs with lower fiber denier are obtained. When the line speed is less than 150 m/min high weighted nonwoven webs are obtained which affects bulkiness positively but makes the process economically non feasible due to unnecessary high weighed product and low production rates . The line speed is adjusted preferably to 250- 400 m/min , which allows obtaining bulky web structures having improved properties.

In the present invention, according to the improved method, a process temperature between 150-200 ° C and nip pressure of 90 to 1 10 N/mm are applied for bonding of fibers by emboss roll. Thus obtained fluffy/lofty web structures shows improved peel, shear performance and mechanical strength properties.

The spunbond web of the present invention is prepared with means of rolls, which comprises of an emboss roll and a pressure roll. Said emboss roll is made from metal plates comprising nips for providing embossed area, whereas pressure roll is made of plain metal plates as non embossed roll. Spunbond nonwoven web is passed through said emboss and pressure roll.

Nonwoven fibers can be bonded with methods of thermal bonding, mechanical or chemical bonding. In the present invention, fibers are preferably thermally bonded by adjusting the temperature and pressure during embossing. The applied temperature on the web is in the range of 150-200 ° C and more preferably it is in the range of 170-190 ° C whereas preferably emboss roll has a higher temperature than pressure roll, wherein the temperature difference is in the range of 0 to 15 ° C. In a further embodiment the nonwoven web has embossed and non-embossed portions that creates bonding and nonbonding areas which affect the bulky / fluffy structure and mechanical strength of nonwoven web, such as peel and shear force. Embossed patterns used as emboss structures in the present invention is shown exemplarly in the figures.

In the present invention, physical and mechanical performance parameters, such as; peel and shear force, air permeability, delamination/peel, can be improved by spunbond process parameters.

Applying improved process conditions with suitable raw material is the critical goal of obtaining good peel and shear performance without delamination and pilling. Furthermore, the technology of the present invention is a comparatively simple method for optimizing material performance with only process parameter changes compared to the common multi-phase ; comprised of film and nonwoven layers; and multi-step production technologies.

In the present invention an improved embossing design is applied on a spunbond nonwoven frontal tape. The embossing design pattern having endless wavy design pattern is provided to create adhesive, fluffy and continuous area to improve peel and shear force.

The spunbond production method has high production volumes per unit time, which creates better productivity.

The selection of raw materials used in formation of nonwoven affects the performance of web structures. Many kinds of polymers have been known to be used as fiber forming materials in this technical field. The preferred polymer type of the present invention is polypropylene, preferably substantially continuous monofilament polypropylene.

In order to further improve the fiber orientation of the spunbond nonwoven frontal tape, Ti02 is added as an additive, so that the physical performance, such as; peel, shear force properties are improved compared to the pure polypropylene. In addition, its processing is also easier. The Ti02 is applied in micronized powder form and in amounts between 0.2- 2.0% preferably 0.5-1.0% of the polymer by weight .

The present invention provides;

A spunbond nonwoven web suitable as loop component of a hook and loop fastening system wherein said spunbond nonwoven web comprises substantially continuous monofilament polypropylene fibers and said loop is embossed having an embossed area characterized in that said spunbond nonwoven web comprises of spunbond-spunbond-spunbond (SSS) fiber layers, wherein said SSS fiber layers comprise of an upper spunbond layer, a middle spunbond layer and a bottom spunbond layer, wherein the upper layer is the layer designated for bonding with a hook, wherein each spunbond fiber layer has different fiber denier.

The present invention provides a polypropylene spun bonded nonwoven fabric, having light weight, is exhibiting excellent feeling to the touch and has high softness. Additionally it is observed that the fabric shows the best resistance to pilling. The nonwoven fabric as shown in FIG. 1 is particularly employed as a material for hygiene products such as diapers, femcare products or nappies as a part of top sheet, back sheet, panels, cuff, waist parts or ears of baby diapers, adult diapers, incontinence diapers, pant like diapers or feminine hygiene article ears.

Frontal tape, landing zone, loop and nonwoven web are used in the present invention in the same context and can be used interchangeably.

Nonwoven web and nonwoven fabric are used in the present invention in the same context and can be used interchangeably.

Calender and roll are used in the present invention in the same context and can be used interchangeably.

EXAMPLES:

Example 1 : Process of Preparing Spunbond Nonwoven Web According to the Method of the Present Invention

Nonwoven fabric sample bonded with an embossing calender having decreased suction and having 23.4% bonded emboss pattern area as shown in Figure 2 is prepared by following the steps; a) providing granulate polypropylene having 0.90 g/cm3 density as raw material in masterbatch, b) titanium dioxide in amount of 0.5-1 % by weight is added in the polypropylene based polymer masterbatch, c) prepared polymer mixture in step a and b, is melted and extruded in the line of extruder. d) melted polymer is sent to spinnerets to form fibers having denier of 2.45 and 1.85 and 1.61 for each, upper, middle and bottom spunbond nonwoven fiber layer respectively. e) in step d formed spinned fibers fall to the conveyor belt one after another successively to lay down with the help of suction system that have 2300 rpm vacuum air and line speed which is set at 620 m/min, f) following the process of afore mentioned steps, which is a spunbond-spunbond- spunbond (SSS) process, a multi-layer nonwoven web having 20g/m2 to 40g/m2 fabric weight is formed, g) formed nonwoven webs are bonded with hot emboss roll, pressure roll system that have the application temperature for pressure roll 176 ° C, emboss roll 183 ° C and a pressure applied onto nonwoven web between 90-1 10 N/mm 2 .

The product prepared according to Example 1 has specific properties as shown at Table 1 and process conditions as shown at Table 2.

Example 2: Process for Preparing Spunbond Nonwoven Web with Lower Fiber Deniers

Nonwoven fabric having embossed pattern structure as shown in FIG 2, is prepared by applying the procedure of Example 1 , whereas the fiber denier and nonwoven web weight is varied. The obtained nonwoven web formed by SSS process has 1.90/1.90/1.50 fiber denier for each upper, middle and bottom spunbond nonwoven fiber layer respectively and 40 g/m 2 nonwoven web weight.

The product has specific properties as shown at Table 1 and process conditions are shown at Table 2.

Example 3: Process for Preparing Spunbond Nonwoven Web with Higher Fiber Deniers

Nonwoven fabric having embossed pattern structure as shown in FIG 2, is prepared by repeating the same procedure of Example 1 , whereas the fiber denier and nonwoven web weight is varied. The obtained nonwoven web formed by SSS process has 3.60/2.2/1.65 fiber denier for each upper, middle and bottom spunbond nonwoven fiber layer respectively and 40 g/m 2 nonwoven web weight.

The product has specific properties as shown at Table 1 and process conditions are at Table 2.

Example 4: Process for Preparing Spunbond Nonwoven Web with Higher Web Weight

Nonwoven fabric having embossed pattern structure as shown in FIG 2, is prepared by repeating the same procedure of Example 1. The obtained nonwoven web formed by SSS process has 2.55/21.95/1.66 fiber denier for each upper, middle and bottom spunbond nonwoven fiber layer respectively and 45 g/m 2 nonwoven web weight.

The product has specific properties as shown at Table 1 and process conditions at Table 2.

TEST METHODS:

Peel Force Test

Peeling in context of the present invention is pulling of attached loop and hook by separating them in opposite direction as seen in Figure 5.

Peel Force test is applied by using Zwick Roell strength equipment to evaluate the peel force of in between spunbond nonwoven frontal tape and hook.

Peel force measurements at maximum force (N/5 cm) are measured with test sample having 35mm x 100mm dimensions, 50 mm clamp distance and 500 mm/min testing speed.

Test steps are as following;

1- Frontal tape nonwoven web test sample is prepared having 35 mm of machine direction (MD) and 100 mm of cross machine direction (CD) dimensions.

2- Hook sample is prepared having a hook 33 mm of length in cross machine direction (CD) and a width of 13 mm in MD direction, wherein said hook is attached onto a side tape of 33 mm in CD 50 mm in MD direction dimensions.

3- The prepared hook sample is put upon the frontal tape and the roll weight having 2kg weight is passed over it for attaching. 4- The frontal tape is attached to the upper clamp while the hook is attached to the lower clamp of the peel force test apparatus (Figure 5).

5- Peel force of the sample is measured as the force necessary until the hook is released from the frontal tape by pulling the clamps apart.

The results are shown at Table 3 as average values of five single measurements.

Results and Evaluation of Peel Force Tests

According to obtained results of peel force shown at Table 3; it can be seen that the peel force values of example 1 and example 4 have nearly equivalent values of 3.18 and 3.20 N/5cm respectively.

Example 1 product having 35g/m2 nonwoven web unit weight shows the same

performance despite having less fiber material compared to example 4 product having 45g/m2 unit weight.

Test results of Example 1 sample compared with example 3 sample reveals that, the delamination risk of example 3 sample is high due to the higher peel force which may lead to delamination of spunbond layers.

The test results show that, the best peel force is observed with the product of example 1. Example 1 presents lighter, ergonomic and economical solution compared to example 4 which shows same peel result but with higher gsm weight values . Hence example 4 material is not economically favourable and example 1 material is the preferred one.

Shear Force Test

Shearing in context of the present invention is pulling of attached loop and hook in opposite direction at the same plane as seen in Figure 6.

Shear Force test is applied by using Zwick Roell strength equipment to measure the shear force between spunbond nonwoven frontal tape and hook.

Shear force measurements at maximum force (N/5 cm) are measured with test stripe having 35 mm x 100mm dimensions, 50 mm clamp distance and 500 mm/min testing speed as following;

1- Nonwoven web test sample is prepared having 35 mm of machine direction (MD) and 100 mm of cross machine direction (CD) dimension, 2- Hook sample is prepared having 33 mm length in cross machine direction (CD) and a width of 13 mm in MD direction, wherein said hook is attached onto a side tape of 33 mm in CD 50 mm in MD direction dimensions.

3- The prepared hook sample is put upon the nonwoven web and the roll weight having 2 kg weight is passed over it for attaching.

4- The frontal tape nonwoven web is attached to the lower clamp while the hook is attached to the upper clamp of the shear force test apparatus (Figure 6).

5- Shear force of the sample is measured as the force necessary until the hook is released from the frontal tape by pulling apart the clamps in plane direction.

The results are shown at Table 3 as average values of five single measurements.

Results and Evaluation of Shear Force Tests

Shear force test results shown at Table 3 reveals that, example 1 does not have significant difference compared to example 3 and example 4. These samples have acceptable shear force properties.

Comparison of example 1 shear test results with example 2 test results reveals that , example 2 has the lowest shear force , which can be attributed to the lower pressure roll temperature. Low shear forces are not desired, which may lead to unfastening of the diaper, therefore not preferred.

Tensile Strength Test

Tensile strength test is the test of durability of nonwoven web. Thereby a pulling force is applied to the nonwoven web in CD or MD direction and the force necessary to break the test sample is measured.

Tensile measurement test is applied by using Zwick strength equipment to evaluate the strength of nonwoven samples.

Tensile measurements at maximum force (N/5 cm) are measured with test sample having 50mm x 250 mm dimensions, 100 mm clamp distance and 100 mm/min testing speed.

The test is followed under ASTM D882-10 standard as;

1- Nonwoven test sample is prepared having 50 mm of machine direction (MD) and 250 mm of cross machine direction (CD) dimensions, 2- The upper and lower parts of the sample is attached to the draw part of the machine and started to pull,

3- Tensile strength (F max ) of the sample is measured as the force necessary until the sample breaks.

The results are shown at Table 3 as CD direction and MD direction results each as average values of five single measurements.

Results and Evaluation of Tensile Strength Tests

According to tensile strength test results of both in the machine direction (MD) and in the cross machine direction (CD) shown at Table 3, Example 1 material shows optimum MD and CD tensile strength values.

For Nonwoven web for use for frontal tape purposes which is the case in the present invention the lower limit of tensile strength value in MD direction is 40-45N. Any increase above the lower limit of MD tensile strength is not very effective on improving mechanical properties of nonwoven web, designated for use for frontal tape purposes in industrial applications. As such Example 2 and Example 4 samples are not favourable, especially Example 4 sample having high weight per unit area is not economically favourable.

For nonwoven web of the present invention the lower limit of tensile strength value in CD direction is 20-25N. Tensile strength values above this range do not contribute to the strength of the sample as in Example 4 the case is. Thereby example 4 having high weight per unit area represents an economically non favourable case. In case of Example 3 against the expectations high upper layer fiber denier values may be the reason for influencing the tensile strength properties negatively. Additionally the lower fiber orientation caused by lower suction due to high fiber denier may lead to lower tensile strength. Higher tensile strength values were expected due to higher fiber deniers but the opposite is the case. The achieved low tensile strengths despite higher fiber denier makes example 3 sample economically non preferred.

Comparing the MD and CD tensile strength test results of the examples, it is seen that there is significant change especially in terms of CD tensile strength due to the lower suction.

As a result in context of improving MD, CD tensile strength of the nonwoven, the suction during the preparation process of the nonwoven web has significant importance. Delamination Test

Delamination test is the test applied for determining durability of the nonwoven web in its thickness direction. Thereby a pulling force is applied to the nonwoven web in thickness direction until the web delaminates.

Test is followed as;

1- Nonwoven test sample is prepared having 50 mm of machine direction (MD) and 250 mm of cross machine direction (CD) dimension,

2- A notch is made at the edge

3- The front and back side of the sample is attached adhesively to the draw part of the test machine and started to pull,

4- Delamination force of the sample is measured as the force necessary until the sample delaminates.

The results are shown as average values of five single measurements.

Results and Evaluation of Delamination Tests

The lamination test results shown at Table 3 give satisfactory delamination values for example 1 and example 4 samples. The lower and in case of Example 2 unsatisfactory test result values are thought to be due to in case of Example 2 sample lower pressure roll temperature and in case of Example 3 sample lower suction in preparation process. The lower emboss temperatures seems to lead to insufficient thermal bonding of the web layers . Whereas the lower suction during the processing seems to lead to lower orientation of the fibers which seems to lead by thermal bonding to irregularities at bonding points which may cause weak bonding, leading to easier delamination.

Comparing the peel & shear force and delamination force test results of example 1 product with other examples, it is seen that example 1 has superior properties and it is chosen as the product.

As a result, when all of the conditions are taken into consideration, it can be seen that, example 1 gives the best results of nonwoven web.

Sample 1 having the best material performance has 35gsm unit weight and fiber denier combination in between 2.45-1.61. Following tables are showing the specific properties of nonwoven fabrics having different fiber denier and unit weight, the production conditions of nonwoven fabrics and the test results which are prepared according to the examples herein.

Table 1 : Specific Properties of Nonwoven fabrics of the Examples

Table 2: Production Conditions of Nonwoven Fabrics of the Examples

Table 3

Table 3: Test results of Nonwoven Fabrics of the Examples