JP4747641B2 - Nonwoven fabric and method for producing the same - Google Patents

Description

  The present invention relates to a nonwoven fabric capable of easily obtaining a high modulus nonwoven fabric that can be used for civil engineering materials, marine materials, industrial materials, building materials, and the like, and a method for producing the same. .

  Conventionally, a thermoplastic polymer is melt-spun, the spun fiber is pulled at high speed with air soccer, etc., then the fiber is opened, a web collected on a moving net is formed, and subsequently heated with a heating roll. Spunbond nonwoven fabrics obtained by mechanically entanglement with thermal bonding or needle punch M / C are nonwoven fabrics for civil engineering such as embankment reinforcement sheets, sandproof sheets, and drainage sheets for tunnels, nonwoven fabrics for industrial materials such as wire clamp tapes and filters. It is used as a non-woven fabric for living materials such as storage bags and packaging substrates, and a non-woven fabric for medical hygiene materials, and its demand is increasing. Among them, as for non-woven fabrics for civil engineering, needle punch type non-woven fabrics are widely used because they are bulky and have excellent buffering properties and high strength.

  However, many conventional needle punched nonwoven fabrics generally have a low modulus. For example, when used as a civil engineering material or marine material, there has been a problem that the construction is difficult to perform due to plastic deformation during construction.

For example, in the past, a technique called a nonwoven fabric for civil engineering that has good compatibility with embankments or unevenness of bedrock and has excellent drainage and a method for producing the same has been proposed (for example, see Patent Document 1). The 5% modulus is about 17 N per unit weight of 100 g / m ² , and when used for civil engineering materials, marine materials, industrial materials, building materials, etc., it tends to be plastically deformed and is not suitable for applications that require a modulus.

Moreover, in order to raise the intensity | strength of a nonwoven fabric, although the technique which applies the resin with which the pigment was kneaded at least on one side is also proposed (for example, refer patent document 2), in this technique, manufacturing cost becomes high, It may be unfavorable for environmental measures at the time of disposal.
JP 2002-38365 A JP 2003-336172 A

  An object of the present invention is to provide a nonwoven fabric excellent in strength and having a high modulus, and a method for producing the same, in view of the above-described problems of the prior art.

  The present invention employs the following means in order to solve such problems.

That is,
(1) A composition having a single fiber fineness of 3.3 to 13.2 dtex by attaching 0.010 to 0.020 ml of a surfactant having a concentration of 1 to 10% to 1 g of a fiber sheet and then performing needle punching treatment. A long-fiber nonwoven fabric in which fibers are entangled and integrated three-dimensionally, and is subjected to a heat treatment at 130 ° C. to 200 ° C. after needle punching, and the fiber surface constituting the nonwoven fabric has a diameter of 0.50 μm to 3.33 μm. It irregularities 0.0125 pieces / [mu] m ² to 0.05 pieces / [mu] m ² possess a density 0.10~0.20g / cm ^3, a basis weight 400~1200g ^{/ m} 2, and basis weight 100 g / ^{m 2} per 10% A nonwoven fabric having a modulus of 60 to 140 N / 5 cm in the longitudinal direction of the nonwoven fabric and 20 to 40 N / 5 cm in the width direction.

(2) The nonwoven fabric according to (1), wherein the nonwoven fabric has a tensile strength per unit weight of 100 g / m ² of 200 to 700 N / 5 cm in the longitudinal direction and 100 to 500 N / 5 cm in the width direction.

( 3 ) The nonwoven fabric according to (1) or (2) above, wherein the fibers constituting the nonwoven fabric are polyester fibers.

( 4 ) A thermoplastic resin is melt-spun and fibers pulled at a high speed of 4000 m / min to 6000 m / min are collected on a net to form a sheet. Then, the sheet has a needle density of 45 to 200 / Under conditions where the needle depth is 5 to 20 mm at cm ² , a surfactant having a concentration of 1 to 10% is attached to the sheet with respect to 1 g of 0.010 to 0.020 ml, and after needle punching, The manufacturing method of the nonwoven fabric characterized by performing the heat processing of 130 to 200 degreeC, and also compressing to the density of 0.10-0.20 g / cm < ³ > with the calender roll heated at 100 to 150 degreeC.

( 5 ) The method for producing a nonwoven fabric according to ( 4 ), wherein the thermoplastic resin is a polyester resin.

  According to the present invention, it is possible to provide a nonwoven fabric having excellent strength and high modulus.

  As a result of intensive studies on the above-mentioned problem, that is, an excellent high modulus nonwoven fabric, the present invention performs a heat treatment at 130 ° C. to 200 ° C. after compressing with a calender roll after needle punching a web made of continuous fibers. , It has been clarified that such problems can be solved all at once.

The fibers constituting the nonwoven fabric of the present invention are composed of filament-like long fibers, and when observing single fibers at an observation magnification of 3000 times by electron microscope observation, the diameter of the fibers is 0.50 μm to 3.33 μm, preferably 0.3. The number of irregularities of 67 μm to 3.00 μm is 0.0125 / μm ^{2 to} 0.05 / μm ² . If the uneven diameter is less than 0.50 μm, the friction between the fibers is insufficient, and it becomes difficult to obtain a high modulus. On the other hand, if the irregularity diameter exceeds 3.33 μm, the deformation of the fiber is remarkable, and the strength of the fineness itself decreases. If the number of irregularities is less than 0.0125 / μm ² , the friction between the fibers is insufficient, and it becomes difficult to obtain a high modulus. On the other hand, when the number of irregularities exceeds 0.05 / μm ² , the deformation of the fiber is remarkable and the strength of the fineness itself is lowered.

  The modulus described in the present invention means the stress when a certain strain is applied to the nonwoven fabric, that is, the force that the object tries to resist in order to keep the original shape, and the 10% modulus described in the present invention Is the stress when the nonwoven fabric is stretched by 10%.

The 10% modulus of the long-fiber nonwoven fabric of the present invention is 60 to 140 N / 5 cm in the longitudinal direction of the nonwoven fabric per 100 g / m ² per unit area, 20 to 40 N / 5 cm in the width direction, and preferably 80 to 120 N / 5 cm in the longitudinal direction. The width is 25 to 35 N / 5 cm. When the 10% modulus is higher than 140 N / 5 cm in the longitudinal direction, or higher than 40 N / 5 cm in the width direction, the sheet becomes too hard to be applied, and the 10% modulus is less than 60 N / 5 cm in the longitudinal direction. Alternatively, when the width is less than 20 N / 5 cm, plastic deformation is likely to occur.

The tensile strength of the long-fiber nonwoven fabric of the present invention is preferably 200 to 700 N / 5 cm in the longitudinal direction of the nonwoven fabric per 100 g / m ² in basis weight, and preferably 100 to 500 N / 5 cm in the width direction, more preferably 400 to 500 in the longitudinal direction. 500 N / 5 cm and 200 to 300 N / 5 cm in the width direction. Less than 200 N / 5 cm in the longitudinal direction or less than 100 N / 5 cm in the width direction is not preferable because the strength is insufficient and the sheet is easily torn during construction.

Basis weight of the long fiber nonwoven fabric of the present invention is preferably 400~1200g / ^{m 2,} more preferably from 600~1000g / ^{m 2.} When the basis weight of the non-woven fabric is higher than 1200 g / m, the sheet is thick, which is not preferable because the needle is easily broken when performing needle punching. Further, when the basis weight of the nonwoven fabric is less than 400 g / m, it is not preferable because the strength is insufficient and the sheet is torn in the above-mentioned use.

  From the standpoint of practicality, it is important to use a fiber having a tensile strength of 2.90 to 3.50 CN / dtex as the fiber constituting the long-fiber nonwoven fabric of the present invention.

  Moreover, it is preferable that the single fiber fineness of the fiber which comprises the long-fiber nonwoven fabric of this invention is 3.3-13.2 dtex, More preferably, it is 4.4 dtex-11.0 dtex, Most preferably, it is 5.5-8. .8 dtex. When the single fiber fineness of the fiber is less than 3.3 dtex, it is not preferable because not only the fiber is easily cut when the needle is punched, but also the rigidity of the fiber itself is insufficient. In addition, when the single fiber fineness of the fiber is larger than 13.2 dtex, the discharge amount per single yarn is large, and therefore, the discharge yarn is not sufficiently cooled, and it is not preferable because the state cannot be stably operated.

  The fiber constituting the long-fiber nonwoven fabric of the present invention is not particularly limited as long as it is a synthetic fiber such as polyester or a copolymer polyester thereof, polypropylene, nylon, etc. Among them, a polyester fiber is preferably used from the viewpoint of nonwoven fabric properties. Is done. Carbon fibers, pigments and dyes including titanium oxide, and other weathering agents may be added to the fibers.

In order to produce the long-fiber nonwoven fabric of the present invention, the fibers discharged from the die are cooled at a high speed of 4000 m / min to 6000 m / min by an ejector while cooling the fibers discharged from the base, and then the fibers opened by the collision plate are placed on the net. After collecting and applying a surfactant, the fibers are mechanically entangled with a needle punch device, further heat-treated at 130 ° C. to 200 ° C., and 0.10 to 100 ° C. to 150 ° C. with a calender roll. It can be compressed to a density of 0.20 g / cm ³ to obtain a product with the required quality.

The needle density at the time of needle punch processing in the present invention varies depending on the shape and type of the needle, but the needle depth is 5 to 20 mm, and preferably 45 / cm ² to 200 / cm ² single-sided or front / back double-sided punch, 50 / Cm ^{2 to} 150 / cm ² is more preferable. When the needle density is less than 45 / cm ² , the fiber entanglement is insufficient, the bondability is poor, and it becomes difficult to put it to practical use, and when the needle density exceeds 200 / cm ² , the sheet Is dense, but is not preferred because there is a problem that the fiber cutting increases and the sheet strength decreases. The needle density is the number of needles driven per unit area of the sheet during needle punching. The needle depth is the distance from the bed plate surface during needle punching to the tip of the needle that is further pierced.

  In the present invention, it is important to apply a surfactant to the sheet before needle punching. The imparting method may be any one of a method of spraying with a spray or the like, a method of impregnating and squeezing the fiber in a surfactant solution bath, and the surfactant in the present invention is preferably uniformly distributed on the fiber. . Therefore, the surfactant is preferably used after being diluted with water or the like so that it can be easily sprayed or impregnated and squeezed, and the pure component concentration of the surfactant is preferably in the range of 1 to 10% by weight. More preferably, it is 3 to 6% by weight.

  It is preferable that 0.010 ml to 0.020 ml of the surfactant is attached to 1 g of the nonwoven fabric during the needle punch processing in the present invention. The application of the surfactant is preferable from the viewpoint of reducing the needle load during needle punching. When the surfactant adhesion amount is less than 0.010 ml, the effect in the present invention is hardly exhibited. In the range where the surfactant adhesion amount exceeds 0.020 ml, the fiber entanglement in the needle punch is insufficient, which is not preferable.

  The type of the surfactant is not particularly limited and can be used as long as it has an effect of reducing friction between fibers, such as dimethyl silicon, polyether polyester, sodium alkyl sulfonate, and the like. Foaming agents, preservatives and the like may be added.

  In the present invention, the sheet is subjected to heat treatment after needle punching. The heat treatment temperature is preferably 130 to 200 ° C for 5 to 15 minutes, more preferably 150 to 180 ° C for 5 to 15 minutes. It seems that the concavo-convex form is formed on the fiber surface due to the shrinkage of the fiber by the heat treatment. Due to this uneven shape, the friction between the entangled fibers is greatly improved, and the modulus of the sheet is improved.

Moreover, in this invention, after heat-processing the sheet | seat which carried out the needle punch process, it compresses to the density of 0.10-0.20g / cm < ³ > with a 100 degreeC-150 degreeC calender roll. By compressing the sheet with a thermal calender roll, the contact between the fibers increases and the modulus is further improved.

  The long-fiber nonwoven fabric obtained by the present invention has high modulus, high strength, and is hardly plastically deformed, and is suitable for civil engineering materials, marine materials, industrial materials, building materials, and the like. It is used for embankment reinforcement as a civil engineering material, tunnel material, as a marine material, a sucking prevention material and a sandproof material for landfill revetment, as an industrial material, as a vehicle member, and as a asphalt roofing material as a building material. In particular, these underground pipes, such as water and sewage pipes, oil pipes, etc., are not digging up the ground to deal with aging due to aging, external loads, or damage due to earthquakes. It is preferable to be used as a repair material by a reversal method that is a non-open-cut repair method that enables repair of the above.

  The reversal method inserts a non-woven fabric impregnated with a resin that is cured by heat or light into the existing pipe while applying reverse pressure to the existing pipe using air pressure or water pressure, and cures the resin in the pressurized state. This is a construction method for constructing a straight pipe, and the construction period has been completed in a very short period of time.

  As the repair material impregnated with the synthetic resin used at this time, the high modulus nonwoven fabric of the present invention is preferably used. This is because when the sheet is inverted and inserted into the repair pipe, if the modulus is low, the rigidity of the sheet is insufficient and the sheet is deformed in the pipe and the shape cannot be maintained.

Hereinafter, the present invention will be described in more detail based on examples. The method for measuring characteristic values shown in the examples is as follows.
(1) Observation of irregularities on the fiber surface:
Use an electron microscope to select 5 single fibers that make up the non-woven fabric, take a single surface photograph of the single fiber (3000 times), and select one range of 20 μm × 20 μm, or When the fiber diameter was 20 μm or less, one range of 10 μm × 10 μm was selected, the irregularities with a diameter of 0.50 μm to 3.33 μm on the fiber surface were counted, and the average value at 5 locations was determined to the first decimal place. The diameter was a circumscribed circle in the form of irregularities, and the diameter was measured. It calculated by rounding off the 5th decimal place of the value which divided the average value of the number of unevenness of the obtained fiber surface by the area of the measurement range.
(2) Single fiber fineness (dtex):
The single fiber fineness of the fibers constituting the nonwoven fabric was calculated by the following method. Take a fiber sample from a needle punched nonwoven fabric, take a magnified photograph of a single fiber (500 times), randomly measure the fiber diameter of n = 50, correct with the polymer density, and round off to the third decimal place. Single fiber fineness was calculated.
(3) Non-woven fabric basis weight (g / m ² ):
Based on JIS-L1906, two samples of 100 cm each in the width direction and the length direction of the sheet were collected, the weight was measured with a balance, and the first decimal place of the two average values was rounded off.
(4) Nonwoven fabric tensile strength (N / 5 cm):
Based on JIS-L1906, three samples with a width of 5 cm and a length of 30 cm, respectively, were taken and measured using a Tensilon tensile tester at a grip interval of 20 cm and a tensile speed of 10 cm / min. The strong value was read, and the average value was calculated by rounding to the first decimal place. The strength per unit weight 100 g / m ² was calculated by the following formula.

Strength per unit weight 100 g / m ² = Nonwoven fabric tensile strength (N / 5 cm) ÷ {Nonwoven fabric basis weight (g / m ² ) / 100}
(5) Nonwoven fabric tensile elongation (%):
Based on the tensile strength measurement, the elongation at the maximum strength was read and the average value was calculated.
(6) Modulus when stretched by 10% nonwoven fabric (N / 5 cm):
Read the length of the sample, that is, the strength value when the grip interval is extended by 10% from the tensile strength curve at the time of measuring the tensile strength and tensile elongation, and round off the first decimal place of the average value. did. The 10% modulus per unit weight 100 g / m ² was calculated by the following formula.

10% modulus per basis weight 100 g / m ² = nonwoven fabric 10% modulus when stretched (N / 5 cm) ÷ {nonwoven fabric basis weight (g / m ² ) / 100}
(7) Non-woven fabric thickness (mm):
Ten samples of 10 cm x 10 cm are taken equally in the width direction of the needle punch product sheet, measured in units of 0.01 mm in thickness with a pressing load of 20 g / cm ² according to JIS-L1906, and the decimal of the average value Calculated by rounding off the third place.
(8) Non-woven fabric density (g / cm ³ ):
The nonwoven fabric density was calculated by the following formula, and the third decimal place was rounded off. Nonwoven fabric density (g / cm ³ ) = {Nonwoven fabric basis weight (g / m ² ) / 10000} ÷ {Nonwoven fabric thickness (mm) / 10}
Examples 1-2
Polyethylene terephthalate having an intrinsic viscosity of 0.66 and a melting point of 262 ° C. is dried at 180 ° C. for 6 hours and then melted in an extruder having a temperature of 285 ° C., and then measured with a metering pump in the spinning M / C width direction. The melt spinning was performed through the arranged spinneret, cooled by a chimney, and pulled and refined at a spinning speed of 5000 m / min by an ejector installed below the spinneret. At this time, the single fiber fineness was 3.54 dtex and 5.66 dtex. Subsequently, the impact plate was subjected to impact charging to open the fibers, and then the fibers were collected on a mesh type moving conveyor to obtain a sheet having a basis weight of 280 g / m ² .
Three sheets of this sheet were laminated, and 0.015 ml of a surfactant having a pure concentration of 5.0% by weight was adhered per 1 g of the sheet using a spraying device, and the number of needles was 150 each with a needle depth of 15 mm with a needle punch M / C. After punching needle / cm ² , heat treatment at 175 ° C. was performed for 5 minutes and compressed to 0.14 g / cm ³ with a calender roll at 120 ° C. to obtain a nonwoven fabric.
As shown in Table 1, when the single fiber strength and the nonwoven fabric characteristics of the obtained nonwoven fabric were investigated, the surface of the constituent fibers had 0.0125 / μm ² or more of irregularities having a diameter of 0.50 μm to 3.33 μm ( FIG. 1: Example 2 Fiber surface reference), a nonwoven fabric useful as civil engineering material having high modulus and high strength.

Comparative Examples 1-2
According to the same method as in Examples 1 and 2, polyethylene terephthalate having an intrinsic viscosity of 0.66 and a melting point of 262 ° C. was dried at 180 ° C. for 6 hours, and then melted in an extruder having a temperature of 285 ° C. Weighed with a pump, melt spun through a spinneret arranged in the spinning M / C width direction, cooled with a chimney, pulled and refined at a spinning speed of 5000 m / min with an ejector installed below the spinneret. At this time, the single fiber fineness was 3.54 dtex and 5.66 dtex. Subsequently, the impact plate was subjected to impact charging to open the fibers, and then the fibers were collected on a mesh type moving conveyor to obtain a sheet having a basis weight of 280 g / m ² .
Three sheets of this sheet were laminated, and 0.015 ml of a surfactant having a concentration of 5.0% by weight was adhered per 1 g of the sheet with a spray device, and the number of needles was 150 / side with a needle depth of 15 mm with a needle punch M / C. A needle punched nonwoven fabric was obtained so as to be cm ² .
As is apparent from Table 1, the 10% modulus per unit weight of 100 g / m ² of the obtained nonwoven fabric satisfies 80 to 120 N / 5 cm in the longitudinal direction of the sheet and 25 to 35 N / 5 cm in the width direction. On the fiber surface, the irregularities having a diameter of 0.50 μm to 3.33 μm were less than 0.0125 / μm ² (see FIG. 2: Comparative Example 2 Fiber Surface Photograph), which was insufficient.

  INDUSTRIAL APPLICABILITY The present invention can be used as a high modulus nonwoven fabric such as civil engineering materials, marine materials, industrial materials, and building materials that have high modulus and high strength and are difficult to be plastically deformed.

2 is an electron micrograph showing the shape of the fiber used in Example 2. FIG. 4 is an electron micrograph showing the shape of the fiber used in Comparative Example 2.

Claims (5)

A component fiber having a single fiber fineness of 3.3 to 13.2 dtex is obtained by applying a needle punching treatment after attaching 0.010 to 0.020 ml of a surfactant having a concentration of 1 to 10% to 1 g of the fiber sheet. Originally entangled and integrated long fiber nonwoven fabric, it is subjected to heat treatment at 130 ° C to 200 ° C after needle punching, and the surface of the fiber constituting the nonwoven fabric has 0 to 0. .0125 pieces / [mu] m ² to 0.05 pieces / [mu] m ² possess a density 0.10~0.20g / cm ^3, a basis weight 400~1200g ^{/ m} 2, and basis weight 100 g / ^{m 2} per 10% modulus nonwoven A non-woven fabric characterized by having 60 to 140 N / 5 cm in the longitudinal direction and 20 to 40 N / 5 cm in the width direction. The nonwoven fabric according to claim 1, wherein the nonwoven fabric has a tensile strength per unit weight of 100 g / m ² of 200 to 700 N / 5 cm in the longitudinal direction and 100 to 500 N / 5 cm in the width direction. The nonwoven fabric according to claim 1 or 2 , wherein the fibers constituting the nonwoven fabric are polyester fibers. After melt spinning the thermoplastic resin and collecting the fibers pulled at a high speed of 4000 m / min to 6000 m / min on a net to form a sheet, the sheet has a needle density of 45 to 200 / cm ² . In a condition where the needle depth is 5 to 20 mm, a surfactant having a concentration of 1 to 10% is attached to the sheet in an amount of 0.010 to 0.020 ml with respect to 1 g of the sheet, and after needle punching treatment, 130 ° C. to A method for producing a non-woven fabric, which is subjected to heat treatment at 200 ° C. and further compressed to a density of 0.10 to 0.20 g / cm ³ with a calender roll heated to 100 ° C. to 150 ° C. The said thermoplastic resin is a polyester-type resin, The manufacturing method of the nonwoven fabric of Claim 4 characterized by the above-mentioned.