JP7853101B2 - Method for manufacturing face mask base fabric - Google Patents

Description

This invention relates to a method for manufacturing a face mask base fabric for use as a cosmetic face mask, and more particularly to a method for manufacturing a face mask base fabric suitable for achieving a neat and defined facial contour.

Traditionally, nonwoven fabric has been used as the base material for cosmetic face masks. This nonwoven fabric is then punched into various shapes and used as the face mask base. These shapes include those that cover the entire face, those that cover the chin and the entire face, those that cover only the chin and the chin, those that cover only the chin, those that cover only the chin, those that cover only the eye area, and those that cover the area below the nose and around the mouth. This face mask base is impregnated with cosmetics containing beauty ingredients such as moisturizing, cleansing, or whitening agents to create a face mask, which is then applied to the face to improve skin beauty.

In recent years, there has been a growing demand for face masks that not only enhance the beauty of the facial skin but also provide a lifting function. This lifting function addresses the issue of sagging cheek skin, which also causes sagging of the jawline (the facial contour from the chin to the temples). The goal is to lift the skin from the chin to the cheeks upwards to create a more defined jawline. Therefore, it has been proposed to incorporate elasticity into the face mask base fabric.

For example, Patent Document 1 proposes using a nonwoven fabric made by accumulating polyester staple fibers having a spiral three-dimensional crimp as a base fabric for face masks. Such a face mask base fabric is desirable because the constituent polyester staple fibers have three-dimensional crimp, resulting in high elasticity. However, polyester staple fibers with three-dimensional crimp are difficult to open using a carding machine. Specifically, the polyester staple fibers tend to become entangled in the needle cloth of the carding machine, making it difficult to open and accumulate the polyester staple fibers at high speed, resulting in a drawback of reduced productivity for face mask base fabrics.

Japanese Patent Publication No. 2019-103663

The object of this invention is to provide a manufacturing method that improves the productivity of face mask base fabric with good elasticity.

The present invention solves the above problems by employing polyester staple fibers that possess both spiral three-dimensional crimp and zigzag two-dimensional crimp. Specifically, the present invention relates to a method for manufacturing a face mask base fabric, comprising the steps of: passing a group of staple fibers, including polyester staple fibers having both spiral three-dimensional crimp and zigzag two-dimensional crimp, through a carding machine to open and assemble the group of staple fibers to obtain a web; applying a water flow to the web to entangle the staple fibers to obtain a nonwoven fabric ; and forming the nonwoven fabric into a predetermined shape, wherein the polyester staple fibers are side-by-side type composite fibers or eccentric core-sheath type composite fibers formed from two polymers with different shrinkage rates, wherein one polymer is polyethylene terephthalate and the other polymer is polytetramethylene terephthalate .

The polyester staple fibers used in this invention possess both spiral three-dimensional crimp and zigzag two-dimensional crimp (Figure 1). A method for inducing spiral three-dimensional crimp in polyester staple fibers involves using latent crimpable composite fibers. Specifically, side-by-side composite fibers or eccentric core-sheath composite fibers formed from two polymers with different thermal shrinkage rates (such as hot water shrinkage rate and dry heat shrinkage rate) can be used. In such composite fibers, polymers with different shrinkage rates are arranged on the left and right sides of the fiber axis. When heated, spiral three-dimensional crimp is expressed with the polymer side with the higher shrinkage rate facing inward. In the case of polyester fibers, polyethylene terephthalate and polytetramethylene terephthalate are used as the two polymers. Polyethylene terephthalate has a low thermal shrinkage rate, while polytetramethylene terephthalate has a high thermal shrinkage rate.

The method for creating a zigzag, two-dimensional crimp in polyester staple fibers is simply to apply mechanical processing. Specifically, passing the polyester fibers through a heated gear roller creates the zigzag, two-dimensional crimp. Generally, when creating spiral, three-dimensional crimp, or zigzag, two-dimensional crimp, the former is first created, and then the latter is added.

The fiber length of the polyester staple fibers is preferably around 10 to 100 mm. If the fiber length is less than 10 mm, the fibers tend to easily fall out of the carding machine. If the fiber length exceeds 100 mm, the fibers tend to become entangled in the carding machine's needle cloth. The fineness of the polyester staple fibers is preferably around 1 to 10 decitex. If the fineness is less than 1 decitex, the fibers tend to become entangled in the carding machine's needle cloth. If the fineness exceeds 10 decitex, the surface of the resulting face mask base fabric tends to become rough, resulting in a poor feel against the skin.

In this invention, it is preferable to use a mixture of polyester staple fibers and cellulose staple fibers. Cellulose staple fibers have excellent hydrophilicity and water retention properties, making them easily impregnated with lotion when used as a face mask base fabric. The preferred mixing ratio of polyester staple fibers to cellulose staple fibers is 100:30 to 100 by mass. If the mixing ratio of polyester staple fibers falls below this range, the elasticity of the resulting face mask base fabric tends to decrease.

For the reasons mentioned above, the fiber length and fineness of the cellulose staple fibers are preferably similar to those of the polyester staple fibers. Cotton fibers and/or rayon staple fibers are preferred as the cellulose staple fibers. In particular, cotton fibers are natural fibers with excellent biodegradability, offering the advantage of being environmentally friendly. However, small amounts of polyester staple fibers and other types of fibers besides cellulose staple fibers may be mixed in.

When the aforementioned group of polyester staple fibers and, optionally, a group of cellulosic staple fibers are passed through a carding machine, both the polyester and cellulosic staple fibers are well opened, and these are then assembled to obtain a web. While conventionally known carding machines can be used, it is preferable to use a parallel carding machine or a flat carding machine with good fiber opening capabilities. The reason why polyester staple fibers can be well opened in a carding machine despite having a helical three-dimensional crimp is thought to be as follows: Specifically, it is believed that the zigzag two-dimensional crimp of the polyester staple fibers used in this invention partially eliminates the helical three-dimensional crimp.

The basis weight of the resulting web is arbitrary, but is generally around 50-100 g/ ^m² . Then, a water flow is applied to this web. A high-pressure water flow is preferred, as the energy of this water flow entangles the short fibers with each other, resulting in a nonwoven fabric with good shape stability. The reason for not using a binder to bond the short fibers and create a nonwoven fabric with good shape stability is that the presence of a binder poses a risk of causing skin irritation, making it unsuitable as a base fabric for face masks.

By shaping this nonwoven fabric into a predetermined shape, such as by punching it out, a face mask base fabric is obtained. Then, the desired cosmetic is impregnated into it, and it is applied to the face to form a face mask. Because the face mask base fabric according to the present invention has excellent elasticity, a lifting function is achieved by applying the face mask while stretching it diagonally upwards from the chin.

The face mask base fabric according to the present invention is manufactured by passing a group of short fibers, including polyester short fibers having both spiral three-dimensional crimp and zigzag two-dimensional crimp, through a carding machine. Therefore, the short fiber group is less likely to become entangled in the carding machine, and is well opened and accumulated, resulting in the production of the face mask base fabric. Consequently, the method according to the present invention has the effect of improving the productivity of face mask base fabric production.

Example 1
As the polyester staple fiber, we prepared "SFYTCC94VWSD" manufactured by Teijin Limited. This polyester staple fiber is a side-by-side composite staple fiber having both spiral three-dimensional crimp and zigzag two-dimensional crimp. One polymer of the composite staple fiber is polyethylene terephthalate, and the other polymer is polytetramethylene terephthalate. The fiber length of this polyester staple fiber is 51 mm and the fineness is 3.3 decitex.
On the other hand, as a cellulose-based staple fiber, we prepared "Corona CD" manufactured by Daiwabo Co., Ltd. This cellulose-based staple fiber is a rayon staple fiber with a fiber length of 40 mm and a fineness of 1.7 decitex.

70 parts by mass of polyester staple fibers and 30 parts by mass of cellulose-based staple fibers were uniformly mixed and passed through a parallel carding machine to open and stack the fibers, obtaining a web with a basis weight of 70 g/ ^m² . This web was transported to a conveyor belt, and a high-pressure water jet was applied from the web side at a jet pressure of 3 MPa using a water jet device with 0.1 mm diameter jet holes arranged in a horizontal row with a hole spacing of 0.6 mm, followed by high-pressure water jets at jet pressures of 5 MPa and 7 MPa. The web was then inverted, and high-pressure water jets were applied twice at jet pressures of 5 MPa and 6 MPa to entangle the polyester staple fibers and cellulose-based staple fibers, and the water was evaporated by heating at 120°C for 120 seconds to produce a nonwoven fabric with a basis weight of 70 g/ ^m² .
Then, this nonwoven fabric was punched out into a predetermined shape to obtain a face mask base fabric.

Example 2
A face mask base fabric was obtained using the same method as in Example 1, except that the mass ratio of polyester staple fibers to cellulose staple fibers was changed to 50 parts by mass of polyester staple fibers and 50 parts by mass of cellulose staple fibers.

Example 3
A face mask base fabric was obtained using the same method as in Example 1, except that cotton fibers with an average fiber length of 25 mm were used instead of the rayon staple fibers used in Example 1.

Example 4
Fifty parts by mass of polyester staple fibers used in Example 1, thirty parts by mass of cellulose-based staple fibers used in Example 1, and twenty parts by mass of "Pentas α" (flat multi-lobed cross-section polyester staple fibers) manufactured by Toray Industries, Inc. as another type of fiber were uniformly mixed and passed through a parallel carding machine to open and stack the fibers, obtaining a web with a basis weight of 70 g/ ^m² . Thereafter, a face mask base fabric was obtained using the same method as in Example 1.

The methods described in Examples 1 to 4 allowed for continuous production of face mask base fabric without the polyester staple fibers becoming entangled in the parallel carding machine, resulting in a highly productive method.

This is a surface photograph showing an example of the polyester staple fiber group used in the present invention.

Claims (3)

A process of passing a group of short fibers, including polyester short fibers having spiral three-dimensional crimp and zigzag two-dimensional crimp, through a carding machine to open and stack the group of short fibers to obtain a web.
A method for manufacturing a face mask base fabric , comprising the steps of applying a water flow to the web to entangle the short fibers and obtain a nonwoven fabric, and forming the nonwoven fabric into a predetermined shape,
The method for producing a face mask base fabric is characterized in that the polyester short fibers are side-by-side type composite fibers or eccentric core-sheath type composite fibers formed from two polymers with different shrinkage rates, wherein one polymer is polyethylene terephthalate and the other polymer is polytetramethylene terephthalate . The method for producing a face mask base fabric according to claim 1, wherein the short fiber group includes a polyester short fiber group and a cellulose-based short fiber group. The method for producing a face mask base fabric according to claim 2, wherein the cellulose-based short fiber group is a cotton fiber group and/or a rayon short fiber group.