Polyolefin articles and methods of making same.

Surface-modified polyolefin object and its manufacturing method

Scope of invention:

The present invention relates to an improved polyolefin article and a method of manufacturing such article. In particular, the present invention relates to a polyolefin article exhibiting a modified surface and a method of manufacturing such article.

The use of various polyolefin compounds to form various forms of objects is known. For example, polyolefins are known to be used to form fibers that can form a wide variety of woven and non-woven materials. Such polyolefin materials usually possess a fairly hydrophobic (non-wettable) surface. If you want to use a fabric or non-woven material on absorbent products such as diapers, handbags, adult incontinence products, training pants, feminine sanitary napkins, etc., it is often worth expecting that this material exhibits a general hydrophilicity. A (wettable) surface to allow water to penetrate through the surface.

In the past, if you want to use a woven or non-woven polyolefin material in personal hygiene products, in addition to the back sheet material, it has been suggested to apply surface treatments such as surfactants to the polyolefin to make the polyolefin material wettable.of (hydrophilic). Unfortunately, such surface treatments are generally naturally easy to fade. That is, although it appears wet when the liquid is initially applied, after a certain amount of water has passed through the polyolefin material, this surface treatment is easy to wash off the polyolefin material. Obviously, after the surface treatment has been washed away from the polyolefin material, the polyolefin material is generally no longer able to display a wettable (hydrophilic) surface, but displays its original hydrophobic surface.

When polyolefin materials are used in personal hygiene products such as diapers, they may have to pass a considerable amount of liquid waste and suffer multiple surges of liquid waste. If polyolefin fabrics with surface active agent type surface treatment are used on diapers, they can usually pass at least the first surge of urine, but become less able to pass urine in each subsequent surge. . Since diapers may experience three or more urinary surges, surfactant-treated polyolefin materials are generally proven to be inadequate for use in specific applications.

Therefore, attempts have been made to develop a surface treatment for polyolefin materials, which is generally not easy to fade, so that the polyolefin material is more permanently wettable. For example, US Patent 4,578,414 (issued March 25, 1986) of Sawyer et al. is directed to wettable olefin polymer fibers. It is described as being a wettable olefin fiber by having incorporated therein at least one of the following set of humectants, wherein the set includes (a) alkoxy with mixed mono-, di- and/or triglycerides Alkyoxylated alkyl phenol, or (b) a polyoxalkylene fatty acid ester, or a mixture of (c)-(b) and any part of (a). Since this invention directly incorporates the surface activating agent into the bulk polymer resin instead of importing a copolymer or applying a surface treatment to the woven fiber structure, it is considered to be different from the previous techniques.

When the surface active agent is directly incorporated into the monolithic polymer resin, the surface active agent must migrate to the surface of the formed object to make the surface wettable. This method is accompanied by certain shortcomings. First of all, blending surface active agents into polymers (through physical mixing) is an independent method to increase the cost of the final product. In addition, the choice of surface-active reagents is limited, because unless it trims the isolate, the reagent must be able to resist mixing at elevated temperatures and must exhibit the desired migration behavior.

It is desirable to produce a polyolefin article with a modified surface such as hydrophilicity, which is less prone to fading than known polyolefin articles exhibiting such a modified surface. In addition, it is desirable to provide a method for denaturing the surface of polyolefin objects.

These and other related purposes are achieved by thermally fusing a part of the copolymer material into a polyolefin with a general hydrophobic base. This copolymer material includes a generally hydrophobic part and a modifying part. The denatured part is usually insoluble in polyolefins. Generally the hydrophobic part is usually soluble in polyolefin.

The thermal fusion of copolymerized materials into polyolefins has been known to give polyolefins a denatured surface that is generally not easy to fade.

In another aspect, the present invention is related to a method of providing a generally hydrophobic polyolefin-modified surface. This method involves contacting a generally hydrophobic polyolefin with a copolymer material when the generally hydrophobic polyolefin is at a temperature above its glass transition temperature. This copolymer material includes a generally hydrophobic part and a denatured part. This generally hydrophobic part is soluble in polyolefin, and the denatured part is insoluble in polyolefin.

In a particularly preferred embodiment of the present invention, the polyolefin fiber with a generally hydrophilic surface is prepared by extruding a generally hydrophobic polyolefin into a fiber shape. When the general hydrophobic polyolefin is present in the extruded plate, it immediately comes into contact with the aforementioned copolymer material. Upon contact, the extruded hydrophobic polyolefin is molten and undergoes a degree of die expansion. Contacting the polyolefin with the copolymer material at this time has proven to be particularly useful in making a fiber with a generally non-fading and hydrophilic surface.

<p>Note: The Chinese and English terms represented by the numbers in the figure are as follows:</p><p>10platform </p><p>12Base </p><p>14inclined surface </p><p>16bottom edge </p><p>18V-shaped barrier means </p><p>20Dong hole </p><p>22dispensing funnel </p><p>24valve </p>

Figure 1 is a perspective view of the test device used in the run-off measurement.

The present invention relates to an article formed of a general hydrophobic polyolefin with a modified surface. The present invention further includes methods for forming such objects.

Polyolefins are already known to those skilled in the art. Any polyolefin that can be processed into an article is considered suitable for use in the present invention. Examples of polyolefins suitable for use in the present invention are homopolymers and copolymers including repeating units formed by one or more aliphatic hydrocarbons, including ethylene, propylene, butene, pentene, hexyl Ene, heptene, octene, 1,3-butadiene, 2-methyl-1,3-butadiene, etc. Polyolefins can be high or low density, and can also be generally linear or branched polymers.

Polyolefins (such as those mentioned previously) are generally hydrophobic in nature. The term "hydrophobic" as used herein refers to a material having a contact angle of at least 90 with water in air. For the purpose of this application, the contact angle measurement is determined by the method described by Good and Stromberg in "Surface and Colloid Science" Volume II (Plenum, 1979).

According to the present invention, a polyolefin object formed of hydrophobic polyolefin is treated with a copolymer material to produce a denatured surface on the object. As for a "denatured" surface, it refers to the case in which the polyolefin surface treated according to the method of the present invention shows characteristics that the untreated polyolefin cannot show. Particularly, in one embodiment, the denatured part is such that the treated polyolefin exhibits the hydrophilicity of a hydrophilic surface. Therefore, although an untreated polyolefin usually exhibits a hydrophobic surface, such a treated polyolefin can exhibit a hydrophilic surface. Although it is mentioned here that the denatured part can be made hydrophilic, it must be understood that other denatured parts can also be used. For example, the denatured part can be abrasion resistant, chemical resistant, or waterproof. As used herein, the term "hydrophilic" refers to a material that has a contact angle of water in the air of less than 90 as measured by the method related to the definition of "hydrophobic" described above. Furthermore, the term "copolymerized" as used herein is intended to refer to a polymer material formed from two or more monomers.

The copolymer material of the present invention may be a linear polymer or a branched polymer. Furthermore, this copolymer may be a random copolymer, a block copolymer, a graft copolymer or the like. This copolymer material contains at least two parts. One part is generally hydrophobic, and the other part is denatured (ie, hydrophilic). When a homopolymer formed from the part of the repeating unit produces a copolymerization situation each exhibiting hydrophilic or hydrophobic properties as defined herein, a specific part must be regarded as generally hydrophilic or hydrophobic .

The generally hydrophobic part of the copolymer material is soluble in the polyolefin present in the polyolefin object. When a homopolymer formed by repeating units of the part is within the interaction range of the polyolefin, a specific hydrophobic part as used herein must be regarded as soluble in the polyolefin . As for the purpose of this application, the range of polyolefin interactions is described by BHKnox in "Bimodal Character of Polyester-Solvent Interactions.I. Evaluation of the Solubility Parameters of the Aromatic and the Aliphatic Ester Residues of Po1y(ethy1ene Terephthalate)"<u style="single">Journal of Applied</u><u style="single">Polymer Science</u>,Vol.21,pp.225-247(1977);"Bimodal Character of Polyester-Solvent Interactions II. Evaluation of the Chemical Structures of the Aromatic and Aliphatic Ester Residues of Poly(ethylene Terephthalate)"<u style="single">Journal of Applied</u><u style="single">Polymer Science</u>,Vol.21 pp.249-266(1977); and "Bimodal Character of Polyester-Solvent Interactions. III. The Effects of Morphology on the Nature of the Interaction of Nonaqueous Solvents with the Aromatic and the Aliphatic Ester Residues of Poly(ethylene Terephthalate)" Journal of Applied Polymer Science, Vol. 21, pp. 267-276 (1977) (the literature and references cited there are all incorporated herein for reference). In the previously cited documents, Knox discusses the range of interactions in terms of polyester. These teachings on determining the range of polyester interaction can be applied to polyolefins by those skilled in the art.

For example, when the polyolefin is polypropylene, the generally hydrophobic part soluble in the polyolefin should have solubility parameters (dispersion, polarity, and hydrogen bonding) completely in the range described below. This range is based on the use of hexene as a model for aliphatic hydrocarbons (dispersed parts) related to the aliphatic residue radius of polyethyleneterephthalate discussed in the literature cited by Knox Measured with =7.24, polarity = 0, hydrogen bond interaction = 0). These solubility parameters define the range of interaction.

<tables><img file="TW213935B_D0001.tif" /></tables>

Generally speaking, the solubility of a generally hydrophobic part can be determined by a part including repeating units present in the polyolefin that can form the polyolefin object. For example, if the object to be processed includes polyethylene with repeating units shown in the following formula:<img file="TW213935B_D0002.tif" />Generally, the solubility of the hydrophobic part can be determined by making the part include the repeating unit shown in the following formula:

<img file="TW213935B_D0003.tif" />The repeating unit is the same as the repeating unit present in polyethylene. Likewise, when the repeating unit of the polyolefin is structurally similar to the hydrophobic part, dissolution can occur more. Therefore, it can be seen that it contains the hydrophobic part of the repeating unit shown in the following formula:<img file="TW213935B_D0004.tif" />It is generally soluble in polymerized propylene, which is represented by the following formula:<img file="TW213935B_D0005.tif" />Other examples of parts suitable for use as hydrophobic parts are saturated hydrocarbons, mono- or poly-saturated hydrocarbons, functionalized hydroxyl groups and the like.

The denatured part should generally not be soluble in the polyolefin forming the polyolefin article. When a homopolymer formed by repeating units of this part is not in the interaction range of the polyolefin, the variable part used here must be regarded as insoluble in the polyolefin. Furthermore, the interaction range of a particular polyolefin can be determined by the method described by Knox.

For example, when the polyolefin is polypropylene, the modified general hydrophilic part that is insoluble in polypropylene should have solubility parameters (dispersion, polarity, and hydrogen bonding) that are not in the aforementioned range.

In particular, when the polyolefin article includes the polypropylene represented by the aforementioned formula, the modified general hydrophilic part can be represented by the following formula:<img file="TW213935B_D0006.tif" />Therefore, when the polyolefin is polypropylene, the copolymer material suitable for use in the present invention can be represented by the following:<img file="TW213935B_D0007.tif" />

In the previous example, the repeating unit in the brackets before X is the generally hydrophobic part that is soluble in polypropylene, and the repeating unit in the brackets before Y is the generally hydrophilic part that is generally insoluble in polypropylene. Alternatively, the copolymer composition can be represented by the following formula:<chemistry general="n"><img file="TW213935B_D0008.tif" /></chemistry>or<chemistry general="n"><img file="TW213935B_D0009.tif" /></chemistry>Where X and Z are integers. Furthermore, the part in parentheses before X is a generally hydrophobic part, and the part before Z generally represents a generally hydrophilic part.

Other examples of the part that can form the variable part of the copolymerized material are (CF₃)_x(CF₂)X,(SO₃)^-X⁺,SiO₂,COOH,OH,NO₂, CH and so on. (SO₃)^-X⁺Part of the example is as in sulfonated castor oil (sodium salt form) (SO₃)-Na⁺. The correct choice of copolymer materials used when processing special polyolefin materials is fairly easy to determine in experiments. The necessary and sufficient conditions for the copolymerization material include at least one polyolefin-soluble generally hydrophobic part and at least one polyolefin-insoluble denatured (preferably generally hydrophilic) part. It should be understood that the copolymerized material may include two or more generally hydrophobic moieties and/or two or more generally hydrophilic moieties. It is preferred that such copolymer materials have a weight average molecular weight (MW) of less than about 10,000. For ease of application, it is best that the copolymer material is liquid at room temperature (23°C).

The copolymerized material is incorporated into the polyolefin by heat fusion. The term "thermal fusion" as used herein refers to the situation in which the copolymerized material contacts the surface of the polyolefin object when the polyolefin in contact is at a temperature above its glass transition temperature. As for the surface contacting the polyolefin object, it means that the copolymerized material is locally applied to the polyolefin instead of being intimately mixed with all polyolefins. The applicant has discovered that the thermal fusion of polyolefin and copolymer material described herein produces polyolefin with a modified surface, which is generally less susceptible to fading than a similarly modified surface that is not formed by thermal fusion.

Without intending to be combined by any principle, it is assumed that the heat of the copolymer material is fused to the polyolefin object, causing this soluble general hydrophobic part to dissolve into the polyolefin object and become entangled in the polyolefin object. In the polymer chain. The insoluble denatured portion of the copolymerized material does not dissolve into the polyolefin, and tends to remain on the surface of the polyolefin object. In this method, the denatured portion provides hydrophilic denaturation characteristics to the surface of the polyolefin.

Thermal fusion is different from the blooming method described in, for example, the previously discussed US Patent 4,578,414. According to the blooming method, a humectant is incorporated into the molten polyolefin material and it is expected to bloom the surface of the fiber formed from the polyolefin/wet extrusion blend. This humectant must be selected to show this blooming phenomenon. Not all humectants exhibit this behavior. For example, if the humectant is an ABA block copolymer (wherein the A block is hydrophobic), the hydrophilic B block may be able to bloom due to the strong absorption of the A block to the polyolefin material. In addition, it is believed that a certain amount of the most humectant will usually remain in the polyolefin rather than frost the surface. Therefore, a higher concentration of humectant must be used to obtain the desired degree of dampness that all humectants can be utilized. By thermally fusing the copolymerized material into the polyolefin, the present invention does not require the use of frosting materials, and it is believed that the applicable copolymerized material can be more fully utilized.

When the denatured part is hydrophilic, the thermal fusion of the copolymerized material and the polyolefin generally produces a more durable hydrophilic surface than known methods. However, for the hydrophobic part of the thermally fused polymeric material, it may be untangled and washed away from the polyolefin. This is more likely to happen if the generally hydrophilic part of the copolymerized material is strongly hydrophilic (that is, has a strong attraction to water). In this situation, when the polyolefin object treated with the copolymerized material is placed in a water environment, the attraction of the hydrophilic part to water can be stronger than that of the general hydrophobic part in the polyolefin; The hydrophobic portion can be released from the polyolefin, which can allow the copolymerized material to enter the water.

It is believed that the use of ABA block copolymers in the present invention may be preferable. In particular, since both A blocks are soluble in polyolefin, the hydrophilic B block can be more firmly fixed to polyolefin.

One way to determine whether a copolymerized material that includes a hydrophilic portion is undesirably easy to fade is to measure the surface tension of the aqueous phase of a treated polyolefin article that has been washed. If the copolymer material is easy to fade and has been pulled away from the polyolefin, the surface tension of the water phase will be reduced. In this situation, the relative permanence of various surface treatments can be compared. This of course assumes that a certain amount of surface treatment is initially present and not excessive. If there is excess surface treatment, these excesses can be expected to be washed off. When the polyolefin object undergoes more repeated washing/drying cycles and still maintains wettability and does not reduce the surface tension of the rinse water like an object with non-thermally fused copolymerized materials, it has thermal fusion in accordance with the present invention. The polyolefin object of the copolymerized material will be regarded as less prone to fading out than the similar polyolefin material that has the copolymerized material on it but is not thermally fused in. This special test method used in the treatment of washing/drying cycles will be described with examples later.

Generally speaking, it is expected that the polyolefin article according to the present invention can go through at least three washing/drying cycles (described later with examples) without losing its hydrophilicity and other properties. Or, it is generally desirable that the object goes through three washing/drying cycles without reducing the surface tension of the washing water used in the third cycle by 5 dynes per centimeter; it is best to go through at least three washing/drying cycles without reducing the surface tension of the washing water used in the third cycle. The surface tension of the flushing water in the third cycle is more than 3 dynes per centimeter.

Alternatively, it is expected that the polyolefin article according to the present invention can undergo at least three washing/drying cycles (described below along with the examples) without reducing the copolymer material initially thermally fused to the surface of the polyolefin article by more than 20%.

The method for forming polyolefin capable of forming polyolefin objects described herein is well known to those skilled in the art. Similarly, the method for forming the surface-treated copolymer complex of the present invention is also widely known. Furthermore, many copolymer complexes suitable for use in the present invention are commercially available. This will be discussed in detail with examples below.

In a preferred embodiment, the copolymer material of the present invention will include a generally hydrophobic portion in a ratio of from 5:1 to about 1:5 (preferably from about 2:1 to about 1:2). In the general situation where the concentration of the hydrophobic part is quite low compared to the total number of hydrophilic denatured parts, it is assumed to be due to the relatively large number of hydrophilic parts caused by the stronger between the hydrophilic part and the water. Attractive, copolymer composition may be more easily faded. Conversely, when there are generally hydrophobic moieties that are relatively large compared to the total number of hydrophilic moieties, it is believed that the copolymerizable complex is generally less susceptible to fading [also (possibly) making the surface less hydrophilic]. This is of course based on the degree of solubility between the general hydrophobic part and polyolefin and the degree of hydrophilicity of the hydrophilic part.

In general, it is desirable that the hydrophilic denatured portion has a molecular weight of from about 45 to about 300, and preferably from about 150 to about 2,000. It is generally desirable for the hydrophobic portion to have a molecular weight of from about 75 to about 300, and preferably from about 750 to about 2,000. If, for example, the molecular weight of the hydrophobic part is less than about 75, this part lacks an effective chain length that can be dissolved and entangled into the polyolefin. In this situation, the copolymerization part may be undesirable and easy to fade. Conversely, if the molecular weight of the hydrophilic denatured part is greater than about 3000, the copolymer material may be too hydrophilic and improperly easy to fade.

The copolymer material of the present invention can be applied to the polyolefin material in an amount sufficient to impart a desired level of surface concentration to the polyolefin article. The amount of copolymerized material applied to the polyolefin will depend on many factors, including the relative efficacy of the denatured part, the ratio of the hydrophobic part to the denatured part in the copolymerized material, and the relative insolubility of the denatured part (the less soluble the denatured part in polyolefin , The more denatured part will be left on the surface of the polyolefin object) and so on. Nevertheless, in general, the copolymerized material is applied to the polyolefin object so that the concentration of the denatured portion present on the surface of the polyolefin object is at least about 0.1% of the total surface area, and preferably at least about 2.0% of the total surface area.

In the second point of view, the present invention relates to a method of providing a modified surface of an article made of generally hydrophobic polyolefin. This method includes the step of contacting the surface of an object including a generally hydrophobic polyolefin with a copolymerized material including a generally hydrophobic portion and a denatured portion. The hydrophobic polyolefin and copolymer materials have been described above. The surface of the polyolefin object is contacted by the copolymerized material when the polyolefin to be contacted is at a temperature higher than its glass transition temperature. Any method of contacting the copolymer material when the polyolefin is at a temperature above its glass transition temperature is suitable for use in the present invention.

In an embodiment of the method according to the present invention, the polyolefin and the copolymer material are brought into contact shortly after the polyolefin has been extruded. For example, when it is desired to form a polyolefin article exhibiting hydrophilic properties, the applicant found that it is particularly desirable to cause the copolymerized material (having a hydrophilic denatured portion) to contact the polyolefin shortly after the polyolefin has been extruded; for example, . In the shape of fiber.

In one embodiment, the aqueous solution of the copolymerized material can be sprayed on the polyolefin as it leaves the top of the die (spinneret). Such methods are known to produce polyolefins with a hydrophilic surface that is particularly resistant to fading. In particular, when the polyolefin leaves the die, it undergoes a phenomenon known to those skilled in the art just like die swelling. "Die expansion" refers to the expansion of a material extruded from a die under pressure. By contacting the polyolefin with the copolymer material when the polyolefin undergoes die expansion, it is believed that a better entanglement between the polyolefin and the generally hydrophobic part of the copolymer material can be caused. However, it should be understood that the polyolefin only needs to be in contact with the copolymer composition when it is above its glass transition temperature, and it does not necessarily need to be in contact with the copolymer composition when the polyolefin undergoes die expansion.

When the polyolefin is leaving a die in the form of fibers, the copolymerization material is applied to the polyolefin. The copolymerization composition should contain from about 0.1-10 (preferably from 0.5-3.0) to the total weight of the aqueous solution. The weight percentage of the copolymer composition in the form of an aqueous solution or suspension is suitably applied to the polyolefin.

Alternatively, an article including polyolefin can be formed and cooled to a temperature below the glass transition temperature of the polyolefin. The copolymer material can then be applied to the surface of an object, and the object has been heated to a temperature above the glass transition temperature of the polyolefin. Generally, the higher the temperature, the fewer times are required to cause the desired degree of entanglement between the hydrophobic portion and the polyolefin at this temperature.

In another point of view, the applicant has discovered that polyolefin fibers treated with copolymer materials according to the present invention have improved practical effects. That is, the polyolefin article of the present invention (when present in the shape of a fiber and formed into a woven or non-woven fabric) is perceived to be tactilely softer than similar polyolefin materials that have not been treated with a copolymerized material according to the present invention. It is assumed (not meant to be limited by this assumption) that the actual effect of this improvement occurs as a result of the reduction of the coefficient of friction between individual fibers due to the presence of the copolymer material. In order to achieve the extent of the actual effect of the improvement caused by the presence of the copolymerized material, it is also very important that the copolymerized material is usually not easy to fade, so that washing does not remove the copolymerized material, but does not remove this desirable softness. Effect.

Polyolefin fibers modified according to the present invention to have a hydrophilic surface are known to be suitable for use in personal hygiene products such as diapers, adult incontinence products, sanitary napkins, handbags, and the like. In this use, the polyolefin fibers according to the present method are formed into non-woven fabrics such as melt-blown fabrics, woven fabrics, and the like. Such nonwoven fabrics will generally have a density of from about 0.005 to about 0.3 grams per cubic centimeter. Such a non-woven fabric can be used as a component other than the back sheet on diapers because it allows multiple passages of urine surge. Diapers and similar products are generally described in U.S. Patent No. 4,710,187 issued to Boland et al. on December 1, 1987; U.S. Patent No. 4,762,521 issued to Rosesler et al. on August 9, 1988; September 1988 U.S. Patent No. 4,770,656 issued to Proxmire et al. on the 13th; and U.S. Patent No. 4,798,603 issued to Meyer et al. on January 17, 1989, these references are incorporated herein by reference.

The present invention can be understood more clearly by referring to the following examples (including comparative examples). However, these examples are not intended to limit the scope of the invention described in the scope of the patent application.

<u style="single">example</u>

In all the following examples, the following test procedures are used. Unless otherwise specified, all percentages are by weight.

<u style="single">Overflow test</u>

Figure 1 illustrates the device used to perform these overflow measurements. Referring to Figure 1, prepare a tilted platform 10. The platform 10 includes a base 12 and an inclined surface 14. The inclined surface 14 has a width of 14 inches and a length of 22 inches along the center line of its long axis. The inclined surface 14 is inclined at an angle of 30°. Located above the bottom edge 16 of the inclined surface 14 is a V-shaped barrier device 18. The V-shaped barrier device 18 functions to inject the liquid flowing down the inclined surface 14 into the hole 20 located in the center of the V-shaped barrier device 18. Suspended above the inclined surface 14 is a distribution funnel 22. The distribution funnel 22 is suitable for supporting 100 ml of liquid, which can be released onto the inclined surface 14 via the valve 24. The height of the valve 24 on the inclined surface 14 is adjusted to allow a gap of 10 mm between the valve 24 and the sample to be tested placed on the inclined surface 14.

Prepare a test sample that is generally rectangular with a width of 8 inches (20.32 cm) and a length of 15 inches (38.1 cm). The test sample is taped on the inclined surface 14 on its four corners. The test sample is generally concentrated on the inclined surface 14, and the funnel 22 is located approximately 7.8 inches (200 mm) from the bottom side (lowest edge) of the test sample and is concentrated on the sample horizontally. The valve 24 is set approximately 10 mm above the upper surface of the test sample. One hundred milliliters of water was put into the leak. In the bucket 22. Water has a temperature of 35C. A collection device is placed under the hole 20. The valve 24 is opened to dispense the 100 milliliters of water contained in the funnel 22 in more than about 95 seconds. The overflow and the amount of water collected in the collection device are measured and recorded.

<u style="single">Rinse/dry cycle</u>

Prepare a general rectangular test sample that is 8 inches (20.32 cm) wide and 15 inches (38.1 cm) long. The test sample is placed in one liter of water at room temperature (about 23C). The sample was forced to remain in the water for 2 minutes and was stirred by a mechanical stirrer at 15-20 revolutions per minute. The test sample is then removed from the rinse water, and the excess liquid is wringed back into the rinse water. The sample was air-dried overnight, and the process was repeated as many times as needed. The surface tension of the rinsing water is measured after each rinsing/drying cycle with the fresh water used for each rinsing/drying cycle. The surface tension of water is a Fischer^TMTensiometer, measured according to ASTM test method D 1590-60.

Example 1

Melt-blown polyethylene and polypropylene fabrics are manufactured by the following method. Ready to be purchased from Aspun of Dow Chemical Company^TM(Trade name) polyethylene pellets and polypropylene pellets purchased from Himont company PF015 (trade name). In Whitlock^TMIn the dryer (dry air), dry these particles at 222F for a minimum of 2 hours. The pellets are then transferred to a Johnson plastic extruder and extruded by melt blown method. These fabrics were formed under slightly different operating conditions as detailed in Table 1. As the polymer leaves the top of the die, an aqueous solution of one or more of the following materials is applied to the polymer. Mapeg^TM CO-8, hydroxyethyl castor oil, CO-8 (trade name) available from Mazer Chemical Company; and Mapeg^TM DO-400, dioleate, available from Mazer Chemical Company.

The concentrations of various materials present in the aqueous solution are shown in Table 1. The aqueous solution is sprayed on the polyethylene as it leaves the top of the die in a molten state. The aqueous solution is sprayed on the molten polyethylene by a spray boom, and the aqueous solution is sprayed on the molten polyethylene by a MasterFlex^TMBangpu passed to the sprayer. The spray is applied so that 1 ounce of polymer receives about 1 ounce (2.83 grams) of aqueous solution. All meltblown fabrics have the basis weights described in Table 1.

The control samples of polyethylene (sample 1) and polypropylene (sample 2) meltblown fabrics were prepared without adding any aqueous solution when the polymer left the die. The various formation conditions and the polymers used are described in Table 1.

<tables><img file="TW213935B_D0010.tif" /></tables>The samples so prepared were then subjected to the above-mentioned overflow test and rinse/dry cycle. The results of these tests are described in Table 2. .<tables><img file="TW213935B_D0011.tif" /></tables>

With reference to Table 2, it can be known that the test sample according to the present invention will release some copolymer materials during the washing/drying cycle. However, the overflow data indicated that these samples remained wettable. The non-wettable samples (1 and 2) caused essentially all water to overflow the test sample and be collected. The wettable samples (3-6) according to the present invention allow water to pass through and are retained by the test sample. This is true even after three rinses.

<u style="single">Example 2</u>

A polypropylene spunbond sample fabric with a basis weight of 0.7 ounces per square yard (23.7 grams per square meter) was post-treated by immersing the sample in an aqueous solution containing 2% of the total weight of the aqueous solution. The sample is then placed in an oven, and the temperature is increased to a temperature (50F) above the glass transition temperature of polypropylene for about 15 seconds. A control sample of polypropylene fabric was also prepared. These control fabrics are untreated or non-ionic surfactants (purchased from Rohm &amp; Haas company Triton^TM X-102 (trade name)]. Triton^TMThe treated control fabric was immersed in 2% Triton^TMIn the aqueous solution. Some samples were not subjected to heat treatment above the glass transition temperature of polypropylene. These samples were subsequently subjected to the above-mentioned overflow test. The results of these tests are described in Table 3.

<tables><img file="TW213935B_D0012.tif" /></tables>It can be known by referring to Table 3 that only the samples according to the invention have low overflow values after the first flush. This indicates the durability characteristics of the surface treatment of the present invention. The control sample with low initial overflow had high overflow after the first rinse due to the non-durable nature of the surface treatment.

Those skilled in the art will understand that the present invention can have many modifications and changes without departing from its scope. Therefore, the detailed descriptions and examples described above are merely illustrative, and in any case, they are not intended to limit the scope of the present invention described in the scope of the following patent applications.