JPS60167958A - Improved knitted fabric and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nonwoven fabric in which a hot melt agent is interposed in a layer between two nonwoven fabrics, and a method for producing the same.

An object of the present invention is to provide a nonwoven fabric with improved web delamination, high tear strength, and excellent doping properties, and a method for producing the same.

In the past, attempts have been made to use hot melt agents as bonding agents for nonwoven fabrics.Generally, hot melt powder is uniformly dispersed in Kuep to heat round objects, or short fibers made of hot melt are heated. It has been attempted to homogeneously blend the fibers with other short fibers, card them, and then heat-treat them to melt the hot-melt agent and join the web.

Separately, bonding of already bonded nonwoven fabrics with different properties using a hot melt agent is also carried out.For example, bonding of nonwoven fabrics made of different materials or nonwoven fabrics of different deniers is used In order to do this, a hot-melt agent is sprayed or applied onto the surface of one non-woven fabric, the other non-woven fabric is layered on top of that, and the fabric is heated to form a single non-woven fabric. −
Among these methods, the former method aims to make the hot melt agent exist throughout the web by uniformly blending hot melt powder and fibers, and to melt and join by heating it. Depending on the amount and the state of dispersion, there were drawbacks such as the nonwoven fabric becoming too hard and fluffing not being suppressed.

In the latter method, the purpose is to join joined nonwoven fabrics, and the surface condition of the joined nonwoven fabrics used is as follows:
The fuzz is suppressed to withstand this lamination process,
Therefore, since it is smooth, the contact area of the surface to be bonded is small, and sufficient bonding cannot be achieved unless a large amount of hot melt agent is used, which has the disadvantage that only a hard nonwoven fabric can be obtained. Rather than uniformly mixing the nonwoven fabric and hot melt agent, which has been attempted in the past,
In addition, instead of bonding the bonded nonwoven fabrics together, by interposing the hot melt agent between the unbonded nonwoven fabrics, the hot melt agent is used not as a bonding material for the entire web, but for bonding the inner layer. The nonwoven fabric obtained by using only
They found that the strength was also improved and arrived at the present invention.That is, the present invention consists of two layers of nonwoven fabric that have not been individually bonded, and a hot melt agent is placed between the two layers. The improved nonwoven fabric is characterized in that it is interposed in a layered state in a melt-bonded state, and furthermore, after interposing a hot melt agent between two unbonded webs, the two webs are bonded together. A method for producing a nonwoven fabric, which is characterized by heat treatment.

The present invention will be explained in more detail below.

In the context of the spunbond method, the nonwoven fabric that has not undergone bonding treatment in the present invention refers to a web in which continuous filaments are taken up by an air sucker and accumulated on a conveyor made of a net. Normally, this web is joined by thermocompression bonding, resin processing, or needle punching to create a nonwoven fabric that can withstand post-processing.
In the present invention, the nonwoven fabric must not undergo such a bonding process. In addition, in terms of short fiber nonwoven fabric, it refers to a two-dimensional web produced by carding, and in this case, the yarn entanglement is larger than that of spunbond, so it is easier to handle.

As for the material of the nonwoven fabric used in the present invention, in the case of a short fiber nonwoven fabric, rayon fiber etc. may be mixed, but in order to suppress the fuzz on the surface, a nonwoven fabric made of thermoplastic synthetic fiber is preferable, and polyethylene Preferred are terephthalate, poly-ε-caprolactam, polyhexamethylene adipamide, polypropylene, and the like.

In the present invention, when two such unbonded nonwoven fabrics are laminated to form one nonwoven fabric, a hot melt agent is interposed between the nonwoven fabrics, but in the case of the spunbond method, As shown in Figure 1, a continuous filament 1.2 extruded from two spinnerets (not shown) is drawn and transferred by an air sucker 3.4 onto a rotating drum 5.6 which has a suction mechanism inside. to form a web 7.8. These webs are reversed by the rotation of the rotating drum 5.6;
The web is transferred onto the web conveyor 9. Between the rotating drums 5.6, for example, a hot-melt powder spreading device 10 is arranged, from which a metered amount of hot-melt agent is spread onto the unbonded web 7 and then between the rotating drums 6. The upper web 8 is superimposed on the sled. Although FIG. 1 shows a hot melt dispersing device, as shown in FIG. 2, a hot melt web or film may be fed out in a roll by installing an unwinding device 11.

In the case of a short fiber nonwoven fabric, single fibers are carded, a hot melt agent is sprinkled on the formed web, the fibrous hot melt agent is layered, and then a predetermined short fiber nonwoven fabric is wrapped with a cross wrapper. All you have to do is overlap them.

Next, the hot melt adhesive used in the present invention may be a commonly used hot melt adhesive, such as a hot melt adhesive characterized by a low melting point such as polyethylene, vinyl acetate, polyamide, or polyester. These agents are appropriately selected depending on the constituent materials of the nonwoven fabric. Further, the form of the hot melt agent may be powder, latex, web, film, etc., but any form is not critical as long as it can be inserted between two sheets of nonwoven fabric.

In general, web or film forms are easier to operate and the properties of the resulting nonwoven fabric are stable, but they have drawbacks such as the inability to finely adjust the amount of hot melt inserted and the need for switching. have. On the other hand, powder and latex forms are preferable because they allow continuous supply and fine adjustment.

A nonwoven fabric made into a single sheet by inserting such a hot-melt agent between unjoined webs is transferred to a heating process, where the hot-melt agent is melted and joined by heating, but there is no heating method. There are two methods: a method of partially thermocompression bonding using a heated roll having an embossed pattern on one side, and a method of fully bonding using hot air, but in the present invention, there is no particular restriction on the heating method.

The fuzziness of the surface of the stacked nonwoven fabrics is determined by the heating conditions, so in order to obtain a nonwoven fabric with minimal surface fuzz, sufficient heating is required, and it is necessary to make the nonwoven fabric as bulky as possible. In order to obtain a nonwoven fabric with excellent softness, it is important to select a lower temperature and pressure bonding conditions that are suitable for this purpose.

Here, one of the features of the present invention is that if a nonwoven fabric does not contain a hot melt agent, if at least a part of the surface layer is not bonded, it will cause fluffing and lack of strength.
Although it could not be used in the next process, by intervening the hot melt agent, even if the surface layer of the nonwoven fabric was not bonded, the intervening hot melt agent melted and even gave a bonding effect. This results in a sufficiently strong nonwoven fabric that can be easily used in the next process. Therefore, it has become possible to obtain a softer nonwoven fabric than ever before.

It was also found that when a nonwoven fabric is heat-treated at a temperature that prevents surface fuzzing, the strength of the obtained nonwoven fabric is improved when a hot melt agent is present, compared to when the hot melt agent is not present. . Furthermore, the nonwoven fabric obtained by thermocompression bonding using a heated roll usually has a thickness of 100? If the nonwoven fabric is thicker than /d, heat transfer will not be sufficient and bonding will not be possible deep into the nonwoven fabric, resulting in delamination, but by interposing a hot melt agent as in the present invention, Even if the thickness is t/-, no delamination will occur.

Next, the present invention will be further explained with reference to Examples.0 Example 1 Using the apparatus shown in FIG. 1, continuous filament webs made of polyethylene terephthalate were formed on two drums, each having a basis weight of 70 r/rt. . Between this web, PES-110H (Toagosei chemical grade, melting point 105-1
10° C.) in powder form using a scattering device at a ratio of to t/rl, and then hot-pressed between two heated rolls, one of which had an embossed pattern. The surface temperature of the roll at this time was 235°C.

On the other hand, as a comparative example, using the same apparatus, continuous filament webs made of polyethylene terephthalate were formed on two drums, each having a basis weight of 75 y.
/rrl, and with the polyester copolymer interposed therebetween, they were overlapped and passed through heated rolls heated to the same temperature of 235° C. to be thermocompression bonded.

When the two nonwoven fabrics thus obtained were compared, the results shown in Table 1 were obtained.

Below is the margin measurement method 1: Tensile strength = 3 tongs, pounding with Tensilon 2: Tear strength Kaniele-Mendorff method 1: Surface fuzz: 50 times of male rubbing with a Gakushin type surface friction measuring device, visual judgment table: Delamination : Check whether the nonwoven fabric can be peeled off by hand after rubbing it 10 times by hand From these results, it can be seen that the nonwoven fabric of the present invention has excellent tensile strength and tear strength, and there is no delamination.0 Example 2 Using the apparatus shown in Figure 1, a continuous filament web made of poly-ε-caprolactam was formed on two drums in the same manner as in Example 1, and each drum had a basis weight of 50 t/r.
RL, and between the webs, nylon 12 (manufactured by Daicel Chemical Industries, melting point SO -120°C) as a polyamide-based hot melt agent was sprayed in powder form at 10 t/uf from a spraying device, Next, it was thermocompressed at 130° C. between two heating rolls with plain surfaces. The surface of the nonwoven fabric obtained in this way was fluffy, but even after being wound up and fed to a needle punch machine, it could be unwound without cutting, and the resulting product also It was soft.

On the other hand, nonwoven fabric without hot melt agent has 1
In thermocompression bonding in a plain four-wheel at 30° C., the strength was low and the web was cut during winding, and the web that was wound up became too fluffy in the next step of unwinding, and could not be unwound.

By interposing a hot-melt agent between two sheets of nonwoven fabric, the present invention improves web delamination, improves tear strength, and provides a nonwoven fabric with excellent drapability compared to conventional methods. It will be done. Therefore, its industrial significance is extremely large.

[Brief explanation of the drawing]

FIG. 1 shows an example of a nonwoven fabric manufacturing apparatus for carrying out the present invention, and FIG. 2 shows a method for inserting a hot melt sheet or film. 1.2... Continuous filament 3.4...
... Air soccer 5.6 ... Rotating drum 7.8 ... Web. 9 songs Web conveyor 10... Powder scattering device 11...
・・・・・・・・・ Unwinding device patent applicant Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] L: Consists of two layers of nonwoven fabric that have been individually bonded, and a hot melt agent is interposed between the two layers in a fused and bonded state. The improved nonwoven fabric λ according to claim 1, wherein the two layers of nonwoven fabric that have not been individually bonded are thermoplastic synthetic fiber nonwoven fabrics obtained by a spunbond method. Method 4 for producing a nonwoven fabric, characterized in that a hot melt agent is interposed between two nonwoven and unbonded webs, and then the two webs are heat-treated. The thermoplastic synthetic fiber non-woven fabric obtained is the thermoplastic synthetic fiber nonwoven fabric according to claim 3.