JPH01132862A - Composite nonwoven fabric and its production - Google Patents

Abstract

PURPOSE: To produce composite nonwoven fabric excellent tensile stretch, feeling and water absorptivity, and useful for gauze or the like by forming many cohesive points in web made of synthetic fiber filaments, by laminating regenerated fiber web on it and by entangling the laminate with high pressure water jets so as to be in a unified state. CONSTITUTION: The objective nonwoven fabric where synthetic fiber and regenerated one are joined together in an mutually entangled state is produced by the following steps: (1) forming synthetic fiber web using synthetic fiber filaments, followed by partially fusing the filaments in the web among them to impart many cohesive points to the web; (2) forming regenerated fiber web using regenerated fiber filaments and superimposing it on at least one surface of the synthetic fiber web; (3) entangling the plural superimposed sheets. of web with high pressure water jets so as to be in a unified state, wherein the total area of the cohesive points in the synthetic fiber web is <=15% based on the whole area, and the cohesive points are placed at an interval of >=5 cm in the longitudinal and transverse directions of the nonwoven fabric surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved synthetic fiber continuous filament nonwoven fabric and a method for producing the same. More specifically, the present invention relates to a nonwoven fabric with improved tensile strength and elongation, texture, water absorption, etc., which is made by intertwining and integrating a web made of continuous filaments of synthetic fibers and a web made of continuous filaments of recycled fibers, and a method for producing the same.

[Conventional technology]

A nonwoven fabric made of continuous filaments of synthetic fibers is known, which is obtained by adding a heat-sealing part to a spun web by heat embossing with a pattern or using a flat heat roll, and bonding and fixing the constituent filaments at the heat-sealing part. ing.

[Problem that the invention seeks to solve]

However, if the nonwoven fabric obtained by the above-mentioned heat fusion method has few or no fusion points, sufficient strength cannot be obtained; increasing the number of fusion points improves the strength, but It has the drawback that the texture is impaired because the points are formed into a film.

Because of this drawback, the production cost of the above-mentioned nonwoven fabric is lower than that of adhesive bonding using a binder, and it does not contain impurities such as a binder (hereinafter referred to as "no binder"). Although it has excellent characteristics such as not coming off, there has been a limit to its application to the medical field and the clothing field for applications where contamination with impurities is averse, such as when working in clean rooms.

The present invention overcomes the above-mentioned problems of the conventionally known nonwoven fabric made of continuous filaments, and has both high tensile strength and good hand feel without impairing the advantages of the nonwoven fabric made of continuous filaments without a binder. The purpose of the present invention is to provide a nonwoven fabric and a method for manufacturing the nonwoven fabric.

[Means for solving problems]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that, contrary to the common sense strength development of synthetic fiber nonwoven fabrics, the present inventors have widened the interval between the fusion points and made the entire fusion point By intertwining and integrating a web made of continuous filaments of synthetic fibers that occupy a small proportion of the area with a web made of continuous filaments of low-strength fibers called recycled fibers, it has a strength that exceeds that of the nonwoven fabric used as the material. , and a nonwoven fabric with improved texture has been obtained.

That is, an object of the present invention is to provide a composite nonwoven fabric in which a synthetic fiber layer made of continuous filaments of synthetic fibers and a regenerated fiber layer made of continuous filaments of recycled fibers are laminated, wherein the synthetic fiber layer includes continuous filaments of synthetic fibers. A large number of fusion points that partially join the comrades by fusion bonding have a total area of 15% or less of the total area of the fusion points,
The synthetic fiber layer and the recycled fiber layer are arranged so as to be dispersed at intervals of 5 cm or more in each of the longitudinal and lateral directions of the nonwoven fabric surface, and the synthetic fiber layer and the recycled fiber layer allow the fibers of one fiber layer to penetrate into the other fiber layer. This is achieved by a composite nonwoven fabric characterized in that it is joined by intertwining.

The method for producing the composite nonwoven fabric includes forming a synthetic fiber web using synthetic fiber continuous filaments, and then partially fusing the synthetic fiber continuous filaments constituting the web to create a large number of fusion points in the synthetic fiber web. On the other hand, a recycled fiber web is formed using recycled fiber continuous filaments, and the synthetic fiber web is laminated on at least one side of the recycled fiber web, and then the laminated plural webs are entangled and integrated by a high-pressure water jet. It is characterized by becoming

At that time, the plurality of fusion points are arranged such that the total area of the fusion points is 15% or less of the corresponding total area, and the plurality of fusion points are distributed at intervals of 5 cm or more in each of the longitudinal and lateral directions of the nonwoven fabric surface. It is preferable to add it.

The most important feature of the composite nonwoven fabric of the present invention is that a part of the recycled fiber continuous filaments in the recycled fiber layer penetrates into the synthetic fiber layer and becomes entangled with the synthetic fiber continuous filaments, thereby joining both layers. . Through this combination and bonding, a nonwoven fabric with strength exceeding that of the nonwoven fabric used as a material and with improved texture can be obtained.

The present invention will be explained in detail below.

The first point of the present invention lies in the use of a synthetic fiber continuous filament web (hereinafter referred to as synthetic fiber web) described below. The fused portions of a synthetic web form a film and fix the fibers, which prevents fiber entanglement due to the action of high-pressure water flow, and the degree of presence of the fused portions is important in order to obtain a nonwoven fabric that satisfies both strength and texture. becomes important.

That is, in the present invention, the fused portion is used as the fused point, and the interval between the fused points is preferably 5 or more in the longitudinal and mechanical directions, or in the direction in which the fibers are mainly oriented and the direction perpendicular thereto. is 10 m5 or more and the proportion of the total area (
A partially fused synthetic fiber web having a occupancy (hereinafter referred to as occupancy) of 15% or less, preferably 5% or less is used. If the interval between the welding points is less than 5 n+, entanglement will not occur freely even if the occupancy is less than 15%, and sufficient strength and sense of unity will not be obtained.

Furthermore, if the occupancy exceeds 15%, the flexibility of the synthetic fiber web decreases, and when combined, a sense of unity cannot be obtained.

The sense of unity mentioned here means that the synthetic fiber web used in the composite and the recycled fiber continuous filament web (hereinafter referred to as the recycled fiber web) do not peel easily, and it is difficult to peel it off by hand, or it is difficult to peel it off with Tensilon. When measuring the peel strength, the web is cut during peeling and the peel strength cannot be measured. Furthermore, unification refers to processing the web so that the above-mentioned sense of unity is obtained.

The shape of the fusion points is not particularly limited, but it is preferable to use dots fused at intervals because a higher degree of entanglement can be obtained.

The fusion method is not particularly limited, but a heated embossing roll, a high frequency welder, or an ultrasonic welder may be used.

The second point of the present invention is to entangle continuous filaments of regenerated fibers in a synthetic fiber web using a high-pressure water stream. Until now, examples have been known in which synthetic fibers, which are stronger than recycled fibers, are added to improve the strength of nonwoven fabrics made of low-strength fibers such as recycled fibers. However, there are no known examples of adding recycled fibers, which are known to have low strength, to improve the strength of nonwoven fabrics made of synthetic fibers.

The present inventors supplied a synthetic fiber web with a recycled fiber web from one side or both sides, and performed an integration process using a high-pressure water stream. It was found that the value was higher than that of the actual value. It is presumed that this is because the recycled fibers are highly hydrophilic, so the fibers are easily moved by the action of high-pressure water, and are strongly intertwined with the synthetic fibers, giving this effect. Furthermore, since the fibers are not adhesively fixed due to integration through entanglement, flexibility is not lost. However, in the case of integration only by entanglement, the stress during initial elongation is generally low, and depending on the application, dimensional stability may be lacking. In this case, by using a synthetic fiber web fused at intervals like the composite nonwoven fabric of the present invention, a nonwoven fabric can be obtained that fixes the fibers to a minimum and has a well-balanced combination of the characteristics of entanglement and the advantages of fiber fusion. .

Furthermore, it is a composite with recycled fibers, which improves the sliminess of synthetic fibers and imparts high water absorption. In the composite nonwoven fabric of the present invention, the synthetic fibers in the synthetic web penetrate and become entangled with the recycled fiber web, although there are differences in degree.

The synthetic fiber continuous filament referred to in the present invention is obtained from thermoplastic polymers such as polyamide, polyester, polyethylene, polypropylene, polyacrylonitrile, etc., and may be a mixture thereof.

The fineness of the single yarn is not particularly limited, but in consideration of texture and the like, it is preferably 5 denier or less.

Furthermore, the recycled fiber continuous filament referred to in the present invention is made of copper ammonia rayon and viscose rayon, and may be a mixture thereof. The single yarn fineness is not particularly limited, but is preferably 3 denier or less in consideration of entanglement and the like.

The basis weight of the composite nonwoven fabric of the present invention is not particularly limited, but -1%> is preferably 10 g/m or more. Also,
It is more preferable that the weight of the recycled fibers is 15% or more based on the weight of the synthetic fibers.If a general binder is used, the feel and flexibility will be significantly reduced if the amount used increases, but the composite nonwoven fabric of the present invention In this case, such a phenomenon does not appear even if the above ratio increases.

The method for joining laminated webs in the composite nonwoven fabric of the present invention is as follows:
For example, this can be done in the following way. The above synthetic fiber web is sandwiched with the recycled fiber web and placed on a screen. The screen is not particularly limited, and the material, mesh size, wire diameter, etc. can be freely selected depending on the intended use. Then, a high-pressure fluid thinner than many nozzles is applied, and at the same time, a reduced pressure is suctioned from below to cause entanglement. The ejection pressure of the high pressure fluid is usually 15 kg.
/rrrG or more is used, and lower than 15kg/+yrG (when the entanglement does not occur sufficiently, strength and sense of unity are often not obtained.In addition, the nozzle diameter used here is not particularly limited.The shape of the high-pressure fluid Although not particularly limited, a columnar flow is preferable from the viewpoint of energy efficiency.The reduced pressure is not particularly limited, but a pressure at which the treated water is sucked to an extent that the action of the high-pressure water flow cannot be prevented is preferable. , such bonding treatment may be performed from both sides.

After the treatment, the composite nonwoven fabric of the present invention can be obtained by drying. Although there is a possibility that a very small portion of the fibers may be cut during this joining process, it is not enough to cause a problem of thread drop. The composite nonwoven fabric obtained in this way can be further adjusted to suit the intended use.
a) Secondary processing such as water treatment may be performed.

[Action of the invention]

According to the present invention, a nonwoven fabric with high tensile strength and good texture is provided. In the present invention, the strength of the composite nonwoven fabric is developed when the welding points are spaced as far apart as possible and the occupancy is as small as possible, contrary to common sense regarding the development of strength of synthetic fiber nonwoven fabrics. Furthermore, recycled fibers, which are low-strength fibers well known to those skilled in the art, are selected as materials for improving strength, and are intertwined with the synthetic fiber layer to form a structure and improve strength. In addition, since it is a composite material made of continuous filaments and does not use binders or the like, there is no thread drop or impurities, and the recycled fibers also provide water absorbency.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

A web of polyethylene terephthalate obtained according to the method described in Japanese Patent Publication No. 48-3802 was heated to a surface temperature of 230°C and a metal roll having an uneven pattern was heated to a surface temperature of 230°C. The fibers were passed between metal rolls having surfaces and partially joined to obtain a synthetic fiber nib having a single fiber fineness of 2 denier and a basis weight of 20 g/rd. In the roll having an uneven pattern, dots of 0.7 dragon diameter were arranged at intervals of 5n+ in the circumferential direction and 7R in the width direction. Further, the ratio of the fused portion to the total area of the synthetic fiber web was 2.5%.

Separately, a copper ammonia rayon spinning dope is spun using a rectangular spinning funnel device that is capable of carrying out the downward tension spinning method, and a liquid containing a large number of filaments is passed through the lower slit of the spinning funnel device. The membrane is flown down and continuously captured on a moving net conveyor, and as it continues to progress, it is subjected to purification treatment, and further subjected to water jet treatment to rearrange the fibers, and then dried to form continuous copper ammonia rayon. A recycled fiber web having a width of 1 m and a basis weight of 18 g/rrf was produced, consisting of fibers (hereinafter referred to as ammonium copper fibers) having a single yarn fineness of 2 d (see Japanese Patent Publication No. 52-6381).

The synthetic fiber web was sandwiched and overlapped with the recycled fiber web and introduced onto a 30-menshi screen moving at a speed of 2 m/ffl1n. From above, 35kg/rr
Water at a pressure of rG is arranged at a density of 80 holes/c11.
, 15 n+φ nozzle.

At the same time, vacuum suction was applied from below at -59 mmHg. After the treatment, it was dried in a dryer to obtain a composite nonwoven fabric (Sample 1). Table 1 shows the characteristic values of sample 1.

In addition, as comparative examples, the physical properties of the synthetic fiber web (sample 2) and recycled fiber web (sample 3) used in the composite, as well as the synthetic fiber web (sample 4) with approximately the same basis weight as sample 1, are also listed in Table 1. .

As shown in Table 1, the composite nonwoven fabric of the present invention (sample 1)
Sample 4, which is a synthetic fiber web with approximately the same basis weight as the sample, has large intervals between fusion points and a small occupancy rate, so there is no major problem with the feel, but on the other hand, it does not have sufficient strength. In comparison, Sample 1, which is a composite nonwoven fabric of the present invention, surprisingly has improved strength compared to Sample 4, which is made of synthetic fibers, even though it is composited with recycled fibers, which are the weakest fibers. Ru. At the same time,
It can be seen that the strength of the composite nonwoven fabric of the present invention exceeds by 1 the sum of the strengths of Sample 2 and Sample 3, which are the raw materials used for composite.

Further, the composite nonwoven fabric of the present invention was treated with 70% sulfuric acid at low temperature to carefully dissolve the regenerated fibers by acid hydrolysis, and the strength of the remaining synthetic fiber portion (sample 5) was measured. The values are also shown in Table 1, and no improvement in strength is seen compared to the strength of the synthetic fiber web (sample 2) before composite. From the above, it is clear that the regenerated fibers play the role of a kind of binder and are organized with the synthetic fiber web through entanglement to develop strength.

The water absorption capacity of the composite nonwoven fabric (Sample 1) of the present invention was measured and the results are shown in Table 2 below. As a comparative example, the water absorption capacity of Sample 2 and Sample 3 used in the composite was also measured, and the results are also listed in Table 2.

Table 2 1) Water absorption rate: Rise height per minute according to JIS L 1079 Virex method.

2) Water absorption: The ratio of the weight of the absorbed hema cell solution to the weight of the test cloth of 1QXIQaa.

The water absorption rate of the composite nonwoven fabric (Sample 1) of the present invention is naturally higher than that of Sample 2, which is made of 100% synthetic fibers, but surprisingly, it is faster than that of Sample 3, which is made of 100% regenerated cellulose.

This is due to the structure in which a hydrophobic synthetic fiber web is surrounded by a highly water-absorbent recycled fiber web, so that the synthetic fibers or the spaces formed by them form a kind of tunnel effect rather than regenerated cellulose alone, and the water-holding capacity of the regenerated cellulose. It is thought that this synergistic effect resulted in an improvement in the water absorption rate, which was a completely unexpected result.

Example 1L-1 Example 1 was repeated, except that several types of metal rolls with different uneven patterns were used instead of the metal roll with uneven patterns for partial bonding used in Example 1, and various A composite nonwoven fabric of a synthetic fiber web and a recycled fiber web having a fused pattern was obtained. Sample 6.8 is a composite nonwoven fabric of the present invention, and sample 7.9°10 is a comparative example. Table 3 shows the characteristic values of these composite nonwoven fabrics.

Sample 7°9.10 with a melting point outside the range of the present invention
When the distance between the welding points is 511 or less, as in sample 7.8, even if the occupancy is within the range of the present invention, sufficient peel strength cannot be obtained, and the back side in particular is small and has a sense of unity. . In addition, the strength ratio before and after compounding is small, and no significant improvement in strength can be expected. Furthermore, when the occupancy exceeds 15% as in sample 10, the sense of unity is impaired and the flexibility is also significantly reduced.

FIG. 1 shows the strength and elongation curve of the composite nonwoven fabric of Sample 6.7. In Sample 7, which is not of the present invention, where the interval between the fused parts is small and the occupancy is large, the fibers are completely fixed at the fused parts, so the stress at the time of initial elongation is large, but the strength at break is low. In comparison, Sample 6 of the present invention has greater strength at break due to the more uniform intertwining of both fibers, which is a feature of the present invention, and has a soft texture due to its low initial modulus. It can be expected that the above will be effective.

The following is a blank space [A web of nylon 6 obtained according to the method described in Japanese Patent Publication No. 48-3802 was placed between a metal roll having an uneven pattern heated to a surface temperature of 190°C and a smooth flat surface heated to the same temperature. Passed through metal rolls with
A synthetic fiber web of rd was obtained. On the surface of the roll having an uneven pattern, rectangles each having a side of 511 and 0.5H were arranged at intervals of 6.5 fins in both the circumferential direction and the width direction. Further, the ratio of the fused portion to the total area of the synthetic fiber web was 9.5%.

Further, by the method shown in Example 1, a recycled fiber web having a single fiber fineness of 1.7 denier and a basis weight of 15 g/rrr was obtained. Synthetic fiber web is sandwiched with recycled fiber web and overlapped.
It was guided onto a 20 mesh screen moving at a speed of 5 m/in. From above, water with a pressure of 50 kg/rrrG is applied to 0, 15
The treatment was carried out by spraying from an n+φ nozzle.

At the same time, a reduced pressure of -5 (lnHg) was suctioned from the lower side. After the treatment, it was dried in a dryer to obtain a composite nonwoven fabric (sample 11). In addition, the regenerated fiber web was superimposed on the synthetic fiber web, and the same as above was applied from the regenerated fiber web side. A composite nonwoven fabric (Sample 12) was obtained through the treatment.Table 4 shows the physical property values of these composite nonwoven fabrics.

Table 4 When nylon 6 is used as the raw material for the synthetic fiber web, the same effect as when ester is used is seen. Even when the recycled fiber web is entangled from one side of the synthetic fiber web as in Sample 12, the effect of the present invention can be seen, although the strength is slightly lower than when the synthetic fiber web is sand-inched (Sample 11).

〔Effect of the invention〕

Since the composite nonwoven fabric of the present invention is configured as described above, it has a well-balanced combination of the effects of entanglement and the advantages of fusion, and has both high tensile strength and good texture. Moreover, since the web layer is made of continuous filaments, and both layers are joined by entangling them with high-pressure water jets, they do not contain impurities such as binders. Therefore, even when used in the medical field, there is no fear of contamination of the affected area, and it can be used in places where dust and pollution are extremely averse, such as clean rooms. In addition, it is highly absorbent because it contains recycled fibers.
It can be used for gauze, wipers, etc., and also has high moisture absorption and texture when made into clothing.

[Brief explanation of the drawing]

Figure 1 shows the composite nonwoven fabric of the present invention (Sample 6) and the comparative example (Sample 6).
It is a graph showing the strong elongation curve of sample 7). Elongation ('/,) Figure 1

Claims (3)

[Claims] 1. a synthetic fiber layer consisting of continuous synthetic filaments;
A composite nonwoven fabric formed by laminating recycled fiber layers made of recycled continuous filaments, the synthetic fiber layer having a large number of fusion points that partially bond the constituting continuous synthetic fiber filaments together by fusion. The total area of the fusion points is 15% or less of the corresponding total area, and they are arranged so as to be dispersed at intervals of 5 cm or more in each of the longitudinal and lateral directions of the nonwoven fabric surface, and the synthetic fiber layer and the recycled A composite nonwoven fabric characterized in that the fibrous layers are joined by allowing the fibers of one fibrous layer to penetrate into and become entangled with the other fibrous layer. 2. After forming a synthetic fiber web using synthetic fiber continuous filaments, the synthetic fiber continuous filaments constituting the web are partially fused together to provide a large number of fusion points to the synthetic fiber web, while the recycled fiber continuous filaments are A composite nonwoven fabric characterized in that a recycled fiber web is formed using a synthetic fiber web, the recycled fiber web is laminated on at least one side of the synthetic fiber web, and then a plurality of laminated webs are entangled and integrated by a high-pressure water jet. manufacturing method. 3. The plurality of fusion points are provided so that the total area of the fusion points is 15% or less of the corresponding total area and is distributed at intervals of 5 cm or more in each of the longitudinal and lateral directions of the nonwoven fabric surface. The method according to claim 2, characterized in that: