Patent Publication Number: US-2021164139-A1

Title: Water absorbing wipe and manufacturing method therefor

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to wipes, and more particularly to a water-absorbing wipe for personal hygiene and baby care. A manufacturing method for the water-absorbing wipe is also disclosed. 
     2. Description of Related Art 
     Wipes are often used in our daily life when, for example, parents change babies&#39; diapers, people have meals in restaurants, or people do skincare. Since wipes are convenient to carry, store and use, they are popular among consumers and having increasingly extensive use in particularly personal hygiene and baby care. 
     Wipes can be used dry or wet to wipe off dust and stains, and can work with water or detergent to remove stubborn stains. For improving wipes in terms of moisture absorption and water absorption, a common solution is to add wood pulp during production of wipe products in order to make wipes more effective in moisture absorption and cleaning. However, wood pulp fibers are natural short fibers, and while they absorb moisture well, their liquid retention ability is relatively inferior. This means wood pulp fibers absorbing water tend to inadvertently release the water when receiving a certain external force. Thus, when using a wood-pulp-containing wipe, a user has to frequently pick up water and detergent with the wipe. This not only causes inconvenient use but also tends to leave behind water drops at the surface of an object to be cleaned, being unfavorable to cleaning. 
     SUMMARY OF THE INVENTION 
     The objective of the present invention is to address shortcomings of the existing products and manufacturing methods by providing a water-absorbing wipe having good water absorption ability and liquid retention ability, and providing a manufacturing method therefor. 
     For achieving the foregoing objective, the present invention implements the following technical schemes. 
     A water-absorbing wipe has upper and lower layers of melt-blown fiber webs, and an intermediate layer of a wood pulp fiber web containing a super absorbent resin, wherein the melt-blown fibers of the melt-blown fiber webs are woven into the wood pulp fiber web. 
     The melt-blown fibers are polyolefin fibers, polyester fibers, polyamide fibers, polyurethane fibers, polylactic acid fibers, or a blend thereof. 
     The melt-blown fiber webs contain one-component melt-blown fibers each having a high-melting-point resin at its surface, melt-blown fibers each having a low-melting-point resin at its surface, or blend fibers of the two. 
     The high-melting-point resin and the low-melting-point resin have a melting-point difference therebetween of ≥20° C. 
     The melt-blown fibers each having the low-melting-point resin at its surface are one-component melt-blown fibers, two-component melt-blown fibers, or a blend of the two. 
     The two-component melt-blown fibers are two-component skin-core melt-blown fibers, two-component segmented-pie melt-blown fibers, or two-component side-by-side melt-blown fibers. 
     The melt-blown fiber webs each form a water-repellent fiber layer. 
     The melt-blown fiber webs each comprise hydrophilic melt-blown fibers. 
     The super absorbent resin is present in the wood pulp fiber web in an amount of 1˜15 g/m 2 . 
     A weight percentage of the wood pulp fiber web in the water-absorbing wipe is greater than 50 wt %. 
     A weight percentage of the wood pulp fiber web in the water-absorbing wipe is 65 wt %-80 wt %. 
     A manufacturing method for a water-absorbing wipe comprises the following steps: 
     (1) mixing wood pulp that has been opened and scattered by an opening roller with the super absorbent resin into a mixture, and blowing the mixture using a blowing nozzle in the presence of an auxiliary air stream to form the wood pulp fiber web containing the super absorbent resin; 
     (2) performing a melt blowing process involving heating and melting a thermoplastic resin; dispersing melt streams of the thermoplastic resin that have been extruded from spinneret plates into fiber bundles having a diameter of ≤10 μm using a high-temperature, high-speed hot air stream, thereby forming the melt-blown fiber webs in the presence of the hot air stream; and joining the melt-blown fiber webs with two side surfaces of the wood pulp fiber web containing the super absorbent resin, so as to form a multi-layer fiber web having the melt-blown fiber webs at its two sides and having the wood pulp fiber web containing the super absorbent resin in its middle; and 
     (3) binding the fiber webs in the multi-layer fiber web together using a heating device, so as to form the water-absorbing wipe having the upper and lower layers of the melt-blown fiber webs and having the intermediate layer of the wood pulp fiber web containing the super absorbent resin. 
     In the step (2), the thermoplastic resin includes two thermoplastic resins having a melting-point therebetween of ≥20° C., in which the melt-blown fiber webs contain one-component melt-blown fibers each having a high-melting-point resin at its surface, melt-blown fibers each having a low-melting-point resin at its surface, or blend fibers of the two. 
     The melt-blown fibers each having the low-melting-point resin at its surface are one-component melt-blown fibers, two-component melt-blown fibers, or a blend of the two, and the spinneret plates have two-component spinneret orifices. 
     The heating device is a hot air oven, a hot rolling roller or a combination thereof. 
     The thermoplastic resin of the step (2) is heated and melted together with a hydrophilic masterbatch. 
     The manufacturing method for the water-absorbing wipe further comprises a step (4), after the water-absorbing wipe is formed in the step (3), coating upper and lower surfaces of the water-absorbing wipe with a hydrophilic coating. 
     By adopting the aforementioned technical schemes, the present invention provides a water-absorbing wipe made using the manufacturing method. With the super absorbent resin in the wood pulp fiber web of the intermediate layer of the disclosed water-absorbing wipe, the water-absorbing wipe when being wetted with water or detergent can have the super absorbent resin rapidly absorb water or the detergent. During wiping, the water-absorbing wipe can prevent water or the detergent from being excessively transferred to the object to be wiped, which could otherwise cause difficulty in cleaning the excessive water or detergent. Instead, it uses the liquid retention ability of the super absorbent resin to slowly release the water or the detergent to the surface of the object to be cleaned, such that stains can be rapidly removed due to the wetness of the wipe. After absorbing a large amount of water or detergent, the wipe can keep the surface dry without leaving behind drops of liquid, and is more suitable for use when the wipe is wet. Moreover, the water-absorbing wipe is effective in removing stains caused by liquids, such as water and urine from the surface of the object to be wiped. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing illustrating manufacturing of a water-absorbing wipe according to Embodiment 1 of the present invention; 
         FIG. 2  is a cross-sectional view of the water-absorbing wipe according to Embodiment 1 of the present invention; 
         FIG. 3  is a cross-sectional view of a water-absorbing wipe according to Embodiment 2 of the present invention; 
         FIG. 4A  is a cut-away view of a skin-core melt-blown fiber according to the present invention; 
         FIG. 4B  is a cut-away view of a two-component side-by-side melt-blown fiber according to the present invention; 
         FIG. 4C  is a cut-away view of a two-component segmented-pie melt-blown fiber according to the present invention; 
         FIG. 5  is a schematic drawing illustrating manufacturing of a water-absorbing wipe according to Embodiment 3 of the present invention; and 
         FIG. 6  is a schematic drawing illustrating manufacturing of a water-absorbing wipe according to Embodiment 4 of the present invention 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For further illustrating the technical schemes of the present invention, the following detailed description of the present invention will be made with reference to particular embodiments. 
     Embodiment 1 
     As shown in  FIG. 1 , the present invention discloses a manufacturing method for a water-absorbing wipe. The method comprises the following steps: 
     (1) mixing wood pulp  11  that has been opened and scattered by an opening roller A 1  with a super absorbent resin  12  into a mixture, and blowing the mixture using a blowing nozzle B 1  in the presence of an auxiliary air stream to form a wood pulp fiber web  13  containing the super absorbent resin  112 ; 
     (2) performing a melt blowing process involving heating and melting a thermoplastic resin; dispersing melt streams of the thermoplastic resin that have been extruded from spinneret plates C 1 , C 1 ′ into fiber bundles having a diameter of ≤10 μm using a high-temperature, high-speed hot air stream, thereby forming melt-blown fiber webs  14 ,  15  in the presence of the hot air stream; and joining the melt-blown fiber webs  14 ,  15  with two side surfaces of the wood pulp fiber web  13 , so as to form a multi-layer fiber web  16  having the melt-blown fiber webs  14 ,  15  at its two sides and having the wood pulp fiber web  13  containing the super absorbent resin  12  in its middle, wherein a weight percentage of the wood pulp fiber web  13  in the multi-layer fiber web  16  is 70 wt %, and the super absorbent resin  12  is present in the wood pulp fiber web in an amount of 4 g/m 2 , while the melt-blown fiber webs  14 ,  15  form water-repellent fiber layers; and 
     (3) binding the fiber webs in the multi-layer fiber web  16  together using a pair of hot rolling rollers E 1  that engage with each other, so as to form the water-absorbing wipe  17  having the upper and lower layers of melt-blown fiber webs  14 ,  15  and having the intermediate layer of the wood pulp fiber web  13  containing the super absorbent resin  12 . 
     As shown in  FIG. 2 , the present invention further discloses a water-absorbing wipe made using the foregoing manufacturing method. The water-absorbing wipe has a laminated structure. The water-absorbing wipe  17  has the upper and lower layers of the melt-blown fiber webs  14 ,  15 , and has the intermediate layer of the wood pulp fiber web  13  containing the super absorbent resin  12 . The melt-blown fibers of the melt-blown fiber webs  14 ,  15  are woven into the wood pulp fiber web  13 . The melt-blown fibers are polyolefin fibers, polyester fibers, polyamide fibers, polyurethane fibers, polylactic acid fibers, or a blend thereof. The blend refers to a blend of two, three, four or all five of polyolefin fibers, polyester fibers, polyamide fibers, polyurethane fibers, and polylactic acid fibers. 
     With the super absorbent resin  12  in the wood pulp fiber web  13  of the intermediate layer of the water-absorbing wipe  17 , the water-absorbing wipe  17  when being wetted with water or detergent can have the super absorbent resin  12  rapidly absorb the water or the detergent. During wiping, by virtue of the liquid retention ability of the super absorbent resin  12 , the water or the detergent is slowly released to the surface of an object to be cleaned, such that stains can be rapidly removed due to the wetness of the wipe. Moreover, after absorbing a large amount of water or detergent, the water-absorbing wipe  17  can keep the surface dry without leaving behind drops of liquid, and is more suitable for use when the wipe is wet. 
     Embodiment 2 
     As shown in  FIG. 3 , the present invention discloses a water-absorbing wipe, which has a laminated structure. The water-absorbing wipe  27  has upper and lower layers of melt-blown fiber webs  24 ,  25 , and has an intermediate layer of a wood pulp fiber web  23  containing a super absorbent resin  22  in addition to wood pulp  21 . Therein, melt-blown fibers of the melt-blown fiber webs  24 ,  25  are woven into the wood pulp fiber web  13 . The melt-blown fiber webs  24 ,  25  may contain one-component melt-blown fibers  20  each having a high-melting-point resin at its surface, melt-blown fibers  20 ′ each having a low-melting-point resin at its surface, or blend fibers of the two. The high-melting-point resin and the low-melting-point resin have a melting-point difference therebetween of ≥20° C. The melt-blown fibers  20 ′ each having a low-melting-point resin at its surface may be one-component melt-blown fibers, two-component melt-blown fibers, or a blend of the two. As shown in  FIG. 4A  through  FIG. 4C , the two-component melt-blown fibers may be skin-core melt-blown fibers  31 , two-component segmented-pie melt-blown fibers  33 , or two-component side-by-side melt-blown fibers  32 . Besides, for the skin-core melt-blown fiber  31 , its skin layer resin  31   b  has a melting point lower than a melting point of its core layer resin  31   a.  For the two-component segmented-pie melt-blown fiber  33  and two-component side-by-side melt-blown fiber  32 , one of their constituent resin  32   b,    33   b  has a melting point lower than a melting point of the other constituent resin  32   a,    33   a.  The two-component melt-blown fibers are made by heating and melting two thermoplastic resins having a melting-point difference therebetween of ≥20° C., and blowing into fibers through two-component spinneret orifices provided on spinneret plates. 
     Since the melt-blown fiber webs  24 ,  25  contains the melt-blown fibers  20 ′ each having a low-melting-point resin at its surface, when the low-melting-point resin in the melt-blown fibers is melted in a hot air oven, the fibers are bound together. This not only enhances the overall strength of the resulting wipe, but also leads to a dense arrangement of the melt-blown fibers, while endowing an adhesive attached to the surfaces of the melt-blown fiber webs  24 ,  25  with improved adhesion. Consequently, the resulting wipe is more wear resistant, and unlikely to pill and fuzz. In addition, the super absorbent resin contained in the wood pulp fiber web  23  of the intermediate layer makes the wipe suitable for use when being wetted with water or detergent, as it prevents the water or the detergent from being excessively transferred to the object to be wiped, which could otherwise degrade the wiping effect. 
     Embodiment 3 
     As shown in  FIG. 5 , the present invention discloses a manufacturing method for a water-absorbing wipe. The manufacturing method comprises the following steps: 
     (1) mixing wood pulp  41  that has been opened and scattered by an opening roller A 4  with a super absorbent resin  42  into a mixture, and blowing the mixture using a blowing nozzle B 4  in the presence of an auxiliary air stream to form a wood pulp fiber web  43  containing the super absorbent resin  42 ; 
     (2) performing a melt blowing process involving heating and melting a thermoplastic resin and a hydrophilic masterbatch  40 ,  40 ′; dispersing melt streams of the thermoplastic resin and the hydrophilic masterbatch  40 ,  40 ′ that have been extruded from spinneret plates C 4 , C 4 ′ into fiber bundles having a diameter of ≤10 μm using a high-temperature, high-speed hot air stream, thereby forming the melt-blown fiber webs  44 ,  45  in the presence of the hot air stream; and joining the melt-blown fiber webs with two side surfaces of the wood pulp fiber web  43  containing the super absorbent resin  42 , so as to form a multi-layer fiber web  46  having the hydrophilic melt-blown fiber webs  44 ,  45  at its two sides and having the wood pulp fiber web  43  containing the super absorbent resin  42  in its middle, wherein a weight percentage of the wood pulp fiber web  43  in the multi-layer fiber web  46  is 78 wt %, and the super absorbent resin  42  is present in the wood pulp fiber web in an amount of 5 g/m 2 , while the melt-blown fiber webs  44 ,  45  comprise hydrophilic melt-blown fibers; and 
     (3) binding the fiber webs in the multi-layer fiber web  46  together using a hot air oven D 4  and a pair of hot rolling rollers E 4  that engage with each other, so as to form the water-absorbing wipe  47  having the upper and lower layers of hydrophilic melt-blown fiber webs  44 ,  45  and having the intermediate layer of the wood pulp fiber web  43  containing the super absorbent resin  42 . 
     Since the melt-blown fiber webs  44 ,  45  comprise hydrophilic melt-blown fibers, the water-absorbing wipe  47  has improved surface wettability, which allows water or detergent to rapidly wet the water-absorbing wipe  47  and be absorbed by the super absorbent resin  42  contained in the water-absorbing wipe  47 , thus being suitable for use when the wipe is wet. Meanwhile, the hydrophilic fibers at the surfaces of the water-absorbing wipe  47  can readily absorb water stains and urine stains on an object to be wiped, thereby removing liquids, such as water stains or urine stains, from the surface of the object to be wiped rapidly. Additionally, the melt-blown fiber webs  44 ,  45  of the water-absorbing wipe  47  are hydrophilic melt-blown fiber webs  44 ,  45  made with the hydrophilic masterbatch added, and this provides the advantages of easy processing and long-lasting hydrophilicity. 
     Embodiment 4 
     As shown in  FIG. 6 , the present invention discloses a manufacturing method for a water-absorbing wipe. The manufacturing method comprises the following steps: 
     (1) mixing wood pulp  51  that has been opened and scattered by an opening roller A 5  with a super absorbent resin  52  into a mixture, and blowing the mixture using a blowing nozzle B 5  in the presence of an auxiliary air stream to form a wood pulp fiber web  53  containing the super absorbent resin  52 ; 
     (2) performing a melt blowing process involving heating and melting two thermoplastic resins having a melting-point difference therebetween of ≥20° C.; dispersing melt streams of the thermoplastic resins that have been extruded from spinneret plates C 5 , C 5 ′ into fiber bundles having a diameter of ≤10 μm using a high-temperature, high-speed hot air stream, thereby forming the melt-blown fiber webs  54 ,  55  in the presence of the hot air stream, wherein the melt-blown fiber webs  54 ,  55  containing melt-blown fibers each having a high-melting-point resin at its surface, melt-blown fibers each having a low-melting-point resin at its surface, or blend fibers of the two; and joining the melt-blown fiber webs  54 ,  55  with two side surfaces of the wood pulp fiber web  53  containing the super absorbent resin  52 , so as to form a multi-layer fiber web  56  having the hydrophilic melt-blown fiber webs  54 ,  55  at its two sides and having the wood pulp fiber web  53  containing the super absorbent resin  52  in its middle, wherein a weight percentage of the wood pulp fiber web  53  in the multi-layer fiber web  56  is 75 wt %, and the super absorbent resin  52  is present in the wood pulp fiber web in an amount of 3 g/m 2 ; 
     (3) binding the fiber webs in the multi-layer fiber web  56  together using a hot air oven D 5 , so as to form the water-absorbing wipe  57  having the upper and lower layers of hydrophilic melt-blown fiber webs  54 ,  55  and having the intermediate layer of the wood pulp fiber web  53  containing the super absorbent resin  52 ; and 
     (4) after the water-absorbing wipe is formed in the step (3), coating upper and lower surfaces of the water-absorbing wipe with a hydrophilic coating by performing a roll coating process using a pair of coating rollers F 5 , where a hydrophilic coating is applied to two sides of the water-absorbing wipe  57  to have the hydrophilic coating cover the surfaces of the melt-blown fibers, thereby forming hydrophilic melt-blown fibers, and in turn forming the water-absorbing wipe  58  having upper and lower layers of the hydrophilic melt-blown fiber webs  54 ,  55  and having an intermediate layer of the wood pulp fiber web  53  containing the super absorbent resin  52 . 
     The melt-blown fibers of the water-absorbing wipe  58  are hydrophilic melt-blown fibers formed by means of roll coating, which have high hydrophilicity and are highly absorbent for both liquid stains on surfaces objects being wiped such as water stains or urine stains and water or detergent, making the water-absorbing wipe  58  more useful in wet environments.