JPH03220354A - Nonwoven fabric for cushioning and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject nonwoven fabric excellent in compression recovery, having a low repeated compression residual strain ratio and suitable for cushioning materials of furnitures, cars, beddings, etc., by blending a fiber having developed crimps with another fiber having a specified softening point. CONSTITUTION:With (A) 30-99wt.% polyester-based side-by-side type conjugated fiber, etc., in which latent crimps are developed, (B) 1-49wt.% polyester-based binder fiber having a softening point >=20 deg.C lower than that of the component (A) is blended and subjected to compression forming while heating, e.g. at a temperature where softening of the component (B) and development of the latent crimps of the component (A) are simultaneously realized, thus obtaining the objective nonwoven fabric having 10-49kg/m<3> apparent density and <=8% repeated compression residual strain ratio.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a nonwoven fabric for cushioning materials, and more specifically, a nonwoven fabric for cushioning materials that can be suitably used as cushioning materials for furniture, vehicles, bedding, etc. It is related to.

(Prior Art) Conventionally, as a nonwoven fabric for cushioning materials, a nonwoven fabric made of a large fineness obviously crimped fiber produced by a double punch method has been known. However, this nonwoven fabric usually has a problem in that it tends to be bulky. As a way to reduce bulk.

Although there is a method of increasing the needle punch density, the problem arises that productivity decreases. In addition, in this nonwoven fabric, since the fibers that make up the nonwoven fabric are arranged perpendicularly (horizontally) to the direction of the compression force, crimping fatigue, so-called sagging, occurs quickly, which is a performance evaluation item for cushioning materials made of urethane foam. The problem is that the repeated compression residual strain rate specified in JIS 6401 increases.

On the other hand, nonwoven fabrics manufactured by a thermal bonding method in which low-melting point fibers are mixed are known instead of the needle punch method. This nonwoven fabric uses actual crimped fibers and latent crimped fibers, and although the obtained nonwoven fabric has a large cyclic compression residual strain rate of about 10 to 15%, it has the problem that it tends to be bulky. are doing. As a way to reduce bulk.

There are nine different methods, including increasing the amount of low melting point fiber mixed, heat treatment at high temperatures, and changing the fineness.
With either method, the resulting nonwoven fabric becomes hard;
There is a problem that the repeated compression residual strain rate becomes large and the function as a cushioning material is lacking.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems in nonwoven fabrics manufactured by thermal bonding, has excellent compression recovery properties, has a low repeated compression residual strain rate, and is suitable for use in furniture, vehicles, bedding, etc. The object of the present invention is to provide a nonwoven fabric for cushioning material that can be suitably used as a cushioning material, and a method for manufacturing the same.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the inventors have found
We have arrived at the present invention. In other words, the present invention is as follows.

1.30% to 99% by weight of fibers with latent crimp, and 1% to 49% by weight of binder fibers having a softening point at least 20°C lower than the melting point of the fibers with latent crimp. 1. A nonwoven fabric for a cushioning material, which is a compression-molded nonwoven fabric containing: an apparent density of 10 to 49 kg/m'' and a repeated compression residual strain rate of 8% or less.

2. 30% or more by weight or more than 99% by weight of fibers with latent crimp
and 1% to 49% by weight of binder fibers having a softening point at least 20° C. lower than the melting point of the latent crimp fibers, and the web is passed through the following manufacturing process A or B. 1. A method for producing a nonwoven fabric for cushioning material, which comprises heat-treating the nonwoven fabric, cooling it below the softening point of the Neuinda fiber while maintaining the compressed state, and then taking out the formed nonwoven fabric.

Step A: The web is heated to a temperature at which the binder fibers soften and latent crimp occurs, and then compression molded at a temperature above the softening point of the binder fibers Step B: The web is heated at a temperature below the softening point of the binder fibers. The gist of the process is to compression mold the web and then heat the web to a temperature at which the binder fibers soften while maintaining the compressed state and latent crimp occurs.

Next, one aspect of the present invention will be explained in detail.

The nonwoven fabric for cushioning material of the present invention is 30% by weight or more and 99% by weight or more.
It is a compression-molded product containing fibers with latent crimp in an amount of 1% by weight or less and 49% by weight or less of binder fibers.

The fibers with latent crimp, which are one of the components of the nonwoven fabric for cushioning materials of the present invention, are polyester-based or polyolefin-based side-by-side type composite fibers. First, latent crimp is preferably expressed due to the difference in shrinkage during dry heat or wet heat treatment. The binder fiber, which is another constituent component, is a polyethylene-based or polypropylene-based fiber having a softening point at least 20° C. lower than the melting point of the fiber in which latent crimp has developed.

Isophthalic acid copolymerized polyethylene terephthalate, etc.
Alternatively, it is a core-sheath type conjugate fiber in which the sheath component is a low melting point polymer, or a side-by-side type conjugate fiber in which one component is a low melting point polymer.

The nonwoven fabric of the present invention is made from a web containing fibers with latent crimp of 30% to 99% by weight and binder fibers of 1% to 49% by weight,
When the web is heat-treated, the latent crimp fibers develop crimps and the binder fibers soften, resulting in compression molding with an apparent density of 10 to 49 kg/m'.

The nonwoven fabric for cushioning material of the present invention has an apparent density of 1O
~49 kg/m'' and a repeated compression residual strain rate of 8% or less. This repeated compression residual strain rate is described in JIS K 6401 (soft urethane foam for cushions).

After measuring the thickness of the nonwoven fabric, the nonwoven fabric was sandwiched between parallel flat plates and compressed at a compression rate of 60 times/min at room temperature to give a compressive strain rate of 50.
% compressive strain was continuously applied 80,000 times, the nonwoven fabric was taken out, left for 30 minutes, and its thickness was measured, and the difference in thickness was divided by the initial thickness and expressed as a percentage. It is something. Namely.

The repeated compression residual strain rate indicates how much the thickness after repeated compression has decreased with respect to the original thickness, and it can be said that the smaller this strain rate is, the better the performance of the nonwoven fabric is.

The nonwoven fabric for cushioning materials of the present invention contains 30% to 99% by weight of fibers with latent crimp, preferably 50% to 90% by weight, and at least 20% by weight below the melting point of the fibers with latent crimp. It contains binder fibers having a low softening point of 1% by weight or more and 49% by weight or less, preferably 5% by weight or more and 30% by weight or less. If the amount of fibers with latent crimp is less than 30% by weight and the amount of binder fibers is more than 49% by weight, the repeated compression residual strain rate of the nonwoven fabric will be higher than 8%, making it impossible to improve the cushioning properties, which is not preferable. .

The nonwoven fabric for cushioning material of the present invention has a repeated compression residual strain rate of 8% or less.

In order to reduce this compression residual strain rate to 8% or less.

It is necessary that the nonwoven fabric has an apparent density of 10 to 49 kg/m", preferably 20 to 30 kg/m'. If the apparent density of the nonwoven fabric is less than 10 kg/m', when the nonwoven fabric is compressed, Since the degree of freedom between the fibers constituting the nonwoven fabric becomes too large, the fatigue of crimp becomes rapid, and the repeated compression residual strain rate becomes higher than 8%, so that it cannot be suitably used as a cushioning material.

When the apparent density exceeds 49 kg/m', the degree of freedom between the fibers that make up the nonwoven fabric decreases, but because there is less space required for compression recovery, the entanglement between the fibers becomes stronger, resulting in a repeated compression residual strain rate of 8 % and becomes extremely thin compared to its original volume before repeated compression, so it cannot be suitably used as a cushioning material.

A method for producing a nonwoven fabric for cushioning material according to the present invention.

First, a web that is a raw material for a nonwoven fabric contains 30% to 99% by weight of latent crimp fibers, preferably 50% to 90% by weight, and at least 20° C. above the melting point of the latent crimp fibers. 1% or more and 49% by weight or less of binder fibers having a low softening point.

Preferably, 5% by weight or more and 30MN% or less is mixed.

Next, a web in which fibers having latent crimp and binder fibers are mixed is heated to a temperature at which the binder fibers are softened and latent crimp occurs.

A process of compression molding at a temperature above the softening point of the binder fiber (
Step A) or a step (Step B) of compression molding the web at a temperature below the softening point of the binder fibers and heating the web to a temperature at which the binder fibers soften while maintaining the compressed state and latent crimp occurs. Heat treated through.

When heat-treating a web in which fibers with latent crimp and binder fibers are mixed, the latent crimp of the fibers with latent crimp is facilitated to occur.

A net conveyor type hot air circulation heat treatment machine with alternating upper and lower blowing can be used. The air volume of this hot air circulation heat treatment machine is preferably about 15 to 50 rn''/min. In order to compression mold the nonwoven fabric, a movable belt-type pressing device with a cooling function is installed immediately after the heat treatment machine. .

As this belt-type pressing device, one consisting of a plurality of rollers can be used. At this time, the roller interval is preferably such that the compression ratio with respect to the bulk density of the web is 50 to 90%. Further, the heat treatment temperature is set to a temperature at which the binder fibers are softened and latent crimp occurs.

Usually, the temperature is 10 to 40°C higher than the melting point of the binder fiber. If the temperature is higher than 40°C, the binder fibers will melt.

The resulting nonwoven fabric becomes hard and loses its texture.
Undesirable.

Next, the heat-treated web is cooled down to below the softening point of the binder fibers while maintaining its compressed state, and then the formed nonwoven fabric is taken out to form a nonwoven fabric.

When cooling the web after heat treatment, it is necessary to cool the web to below the softening point of the binder fibers while maintaining the compressed state following the heat treatment.

When the compressed state is released and cooled, the repeated compression residual strain rate is 8% or less, excellent cushioning properties, and the apparent density is 1.
It was not possible to obtain a nonwoven fabric with a weight of 0 to 49 kg/m.
Undesirable.

In addition, in the present invention, it is also possible to use actually crimped fibers having crimps as part of the fibers having latent crimps. A nonwoven fabric according to the present invention can be obtained if the latent crimp fibers and binder fibers are each contained in the web in the above-mentioned weight percent ranges. Further, in the manufacturing process, the web may be compressed by heating and compressed and cooled using a mold or the like, or the nonwoven fabric of the present invention may be molded again. Furthermore, for example, it may be integrally molded into the shape of a vehicle seat, furniture, bedding, or the like.

(Example) Next, the present invention will be specifically described based on Examples. In addition, various characteristics in the examples were measured by the following methods.

Melting point (℃): Using a microscope melting point measurement device manufactured by Mettler, two fibers are placed on a hot stage so as to cross each other, and when the temperature is raised at a heating rate of 2℃/min, the intersection of the fibers deforms. and find the temperature at which it fuses.

This was taken as the melting point.

Softening point (°C): Using a Mettler microscope melting point measuring device, two fibers are placed on a hot stage so that they cross each other, and when the temperature is raised at a heating rate of 2°C/min, the intersection point of the fibers is Find the temperature at which deformation begins.

This was taken as the softening point. When the fibers were composed of two types of polymers with different softening points, the lower temperature was taken as the softening point.

Dimensions (thickness) (round): JIS K 6401-5
According to the method described in 2, using a measuring instrument with a minimum scale of 1 mm or less, measurements were taken at three or more locations without deforming the sample, and the average value was determined.

Apparent density (kg/m'): JIS K 6401
According to the method described in -5-3, measure the dimensions of the sample to determine the volume V (mm3), and use a scale with a weighing capacity of 0.1 g or less to calculate the mass M (g) of the sample to 0. Find up to .1g,
The apparent density D (kg/m') was calculated using the following formula.

D= (M/V)x106−−−−・−・−−1 ■Repetitive compression residual strain rate (%): JIS K 64
The thickness t of the sample piece was determined according to the method described in 01-5-6.

After measuring (am,), the same sample piece was sandwiched between parallel flat plates.

After continuously applying compressive strain with a compressive strain rate of 50% at room temperature 80,000 times at a compression rate of 60 times/min, the sample piece was taken out and left for 30 minutes, and its thickness t, (ma +
) is measured, and the repeated compression residual strain rate C is determined by the following formula 0.
(%) was calculated.

C= [: (to −t + ) /lo] xt
00 ■Compressive stress (kg): 5 c of nonwoven fabric
A sample piece cut into a size of m x 5 cm was prepared, and a compression test was performed on the sample piece using a compression tester to determine the compressive stress (
kg) was calculated.

Compression recovery rate (%): In the compression test, draw a compression curve as shown in Figure 1, and calculate the compression stress X + (kg) and areas A and B.
was determined, and the compression recovery rate (%) was calculated using the following formula (2).

Compression recovery rate = CB/ (A+B))X100 ■
Thermoformability: As shown in Fig. 2(i), the sample piece 1 was fixed to the jig 2 by bending it at an angle of 90 degrees, and was
After being heat-treated for a minute, it was left to cool at room temperature for 5 minutes.

After cooling, sample piece 1 is taken out from jig 2.

The angle θ (deg) of the thermoformed sample piece 1 as shown in FIG. 2 (2) was measured to evaluate thermoformability.

Example 1 70% by weight side-by-side type polyester composite fiber having a melting point of 256° C., a single fiber fineness of 2.5 denier, and a cut length of 51 mm was used as a fiber having latent crimp.

In addition, 30% by weight of core-sheath type polyester composite fibers with a softening point of 100°C, a single filament fineness of 4 deniers, and a cut length of 51 mm were used as the binder fibers, and were oriented in one direction by the carding method to reduce the bulk density. A web of 4.8 kg/m" was prepared, and this web was subjected to batch heat treatment using a hot air circulation dryer to develop the latent crimp of the fibers having the aforementioned latent crimp. The treatment conditions were as follows: Temperature: 145℃, air volume: 8m
1/min, and the processing time was 5 minutes. Simultaneously with the appearance of crimp,
The web was compressed in a dryer.

Next, the web is taken out from the dryer and cooled at room temperature to below the softening point of the binder fibers while maintaining the compressed state, and the ratio of the bulk density of the nonwoven fabric to the bulk density of the web is determined.
That is, a sheet-like heat-adhesive nonwoven fabric was obtained which was compression-molded to a compression ratio of 76%.

The obtained sheet-like thermally bonded nonwoven fabric had a thickness of 10 mm.

The apparent density was 20.0 kg/m''. The properties of this nonwoven fabric are shown in Table 1.

Example 2 The web having a bulk density of 4.8 kg/m' produced in Example 1 was compression molded at room temperature, and then heat-treated in the same manner as in Example 1 while maintaining the compressed state.

Latent crimp of fibers with latent crimp was developed.

Next, the web was taken out of the dryer and cooled at room temperature to below the softening point of the binder fibers while maintaining the compressed state, to obtain a sheet-like heat-adhesive nonwoven fabric compression-molded to a compression ratio of 76%.

The thickness of the obtained sheet-shaped thermally bonded nonwoven fabric was 10M.

The apparent density was 20.0 kg/m'. The properties of this nonwoven fabric are shown in Table 1.

Example 3 The web having a bulk density of 4.8 kg/m' produced in Example 1 was heat-treated using a net conveyor-type hot air circulation heat treatment machine with upper and lower alternate blowing, and the fibers with latent crimp were heated. Crimp developed. The processing conditions were a temperature of 145°C.
The air volume was 30 m'/min, the processing speed was 10 m/min, and the processing time was 1.5 minutes.

Then, following heat treatment, until the temperature of the web drops below the softening point of the binder fibers.

After the web is compression-molded using a movable belt-type holding device with a cooling function that has a pair of upper and lower belts arranged immediately after the heat treatment machine, the web is taken out from the holding device and kept in a compressed state. .

A sheet-like heat-adhesive nonwoven fabric was obtained by cooling to a temperature below the softening point of the binder fibers at room temperature and compression molding to a compression ratio of 75%.

The obtained sheet-like thermally bonded nonwoven fabric had a thickness of 11 mm.

The apparent density was 19.2 kg/m''. The properties of this nonwoven fabric are shown in Table 1.

Example 4 90% by weight of a side-by-side type polyester composite fiber having a melting point of 256° C., a single fiber fineness of 2 denier, and a cut length of 51 mm was used as a fiber having latent crimp.

In addition, 10% by weight of core-sheath type polyester composite fiber with a softening point of 100°C, a single fiber fineness of 2 denier, and a cut length of 51 mm is used as the binder fiber, and the bulk density is 4.1 kg.
A crosslay web of /m' was prepared, and in the same manner as in Example 1, this web was heat-treated using a hot air circulation dryer to develop the latent crimp of the fibers having the latent crimp. A bonded nonwoven fabric was obtained.

The processing conditions were a temperature of 165°C, an air flow rate of 50 m'/min, a processing lotus degree of 8 m/min, and a processing time of 1.9 minutes.

Next, following the heat treatment, the web was compression-molded using a moving belt-type presser with a cooling function in the same manner as in Example 3, and then the web was taken out from the presser and maintained in a compressed state. The mixture was then cooled to below the softening point of the binder fibers at room temperature to obtain a sheet-like heat-adhesive nonwoven fabric compression-molded to a compression ratio of 85%.

The resulting sheet-like thermally bonded nonwoven fabric had a thickness of 42 mm.

The apparent density was 27.3 kg/m'. The properties of this nonwoven fabric are shown in Table 1.

Example 5 90% by weight of a side-by-side type polyolefin composite fiber having a melting point of 163°C, a single filament fineness of 2 denier, and a cut length of 511III11 was used as a fiber having latent crimp.

In addition, 10% by weight of core-sheath type polyolefin composite fiber with a softening point of 123°C, single yarn fineness of 2 denier, and cut length of 51 rhymes is used as the binder fiber, and the bulk density is 5.3 kg.
/m'' crosslay web was prepared, and in the same manner as in Example 1, this web was heat-treated using a hot air circulation dryer to develop the latent crimp of the fibers having the latent crimp, and A bonded nonwoven fabric was obtained.

The processing conditions were a temperature of 140° C., an air flow rate of 50 m'/min, a processing speed of 10 m/min, and a processing time of 1.5 minutes.

Next, following the heat treatment, the web was compression-molded using a moving belt-type presser with a cooling function in the same manner as in Example 3, and then the web was taken out from the presser and maintained in a compressed state. The mixture was then cooled to below the softening point of the binder fibers at room temperature to obtain a sheet-like thermally bonded nonwoven fabric compression-molded to a compression ratio of 80%.

The obtained sheet-shaped heat-adhesive nonwoven fabric had a thickness of 39 mm.

The apparent density was 26.5 kg/m'. The properties of this nonwoven fabric are shown in Table 1.

Comparative Example 1 70% by weight of polyester fibers having a melting point of 256°C, a single filament fineness of 6 denier, and a cut length of 75 mm were used as actual crimped fibers, and a softening point of 100°C was used as a binder fiber.
A web with a bulk density of 6.5 kg/m was created by using 30% by weight of core-sheath type polyester composite fibers with a single fiber fineness of 4 denier and a cut length of 51 mm, and oriented in one direction by the carding method. In the same manner as in Example 3, this web was heat treated using a net conveyor type hot air circulation type heat treatment machine with upper and lower alternate blowing, to obtain a thermally bonded nonwoven fabric.The treatment conditions were as in Example 3. The conditions were the same.

Next, after the web is compression-molded using a moving belt-type presser with a cooling function, the web is taken out from the presser and cooled to below the softening point of the binder fibers at room temperature while maintaining the compressed state. The compression rate is 68%.
A sheet-like heat-adhesive nonwoven fabric was obtained by compression molding.

The obtained sheet-like thermally bonded nonwoven fabric had a thickness of 11 mm.

The apparent density was 20.3 kg/m'. The properties of this nonwoven fabric are shown in Table 1.

Example 6 60% by weight of side-by-side type polyester composite fiber having a melting point of 256° C., a single fiber fineness of 2.5 denier, and a cut length of 51 holes was used as a fiber having latent crimp.

In addition, 20% by weight of core-sheath type polyester composite fiber with a softening point of 100°C, a single yarn fineness of 2 denier, and a cut length of 51 mm is used as the binder fiber, and a polyester fiber with a single yarn fineness of 6 denier and a cut length of 75 m + n is used. Textile! 120
% by weight to create a crosslay web with a bulk density of 5.3 kg/m'', and in the same manner as in Example 1, this web was heat treated using a hot air flute dryer to A thermally bonded nonwoven fabric was obtained by developing latent crimp in the crimped fibers.The processing conditions were as follows.

The conditions were the same as in Example 4.

Next, following the heat treatment, the web was compression-molded using a moving belt-type presser with a cooling function in the same manner as in Example 3, and then the web was taken out from the presser and maintained in a compressed state. The mixture was then cooled to below the softening point of the binder fibers at room temperature to obtain a sheet-like heat-adhesive nonwoven fabric compression-molded to a compression ratio of 79%.

The obtained sheet-shaped thermally bonded nonwoven fabric has a thickness of 40 mm.

The apparent density was 21.4 kg/m''. The properties of this nonwoven fabric are shown in Table 1.

Comparative Example 2 20% by weight of a side-by-side type polyester composite fiber having a melting point of 256° C., a single fiber fineness of 2.5 denier, and a cut length of 51 mm was used as a fiber having latent crimp.

In addition, 20% by weight of core-sheath type polyester composite fiber with a softening point of 100°C, a single yarn fineness of 2 denier, and a cut length of 51 mm was used as the binder fiber. 60% polyester fiber by weight
A crosslay web with a bulk density of 5.4 kg/m'' was prepared, and heat treated in the same manner as in Example 4 to obtain a thermally bonded nonwoven fabric, which was then compression molded to a compression ratio of 75%. A sheet-like heat-adhesive nonwoven fabric was obtained.

The obtained sheet-shaped thermally bonded nonwoven fabric had a thickness of 40 mm.

The apparent density was 21.6 kg/rri''.

The properties of this nonwoven fabric are shown in Table 1.

Comparative example 3 Same as Example 6 except that the compression ratio was 48%.

A sheet-like thermally bonded nonwoven fabric was obtained by heat treatment and compression molding.

The thickness of the obtained sheet-shaped heat-adhesive nonwoven fabric was 41 marks.

The apparent density was 8.7 kg/m''. The properties of this nonwoven fabric are shown in Table 1.

Comparative example 4 Same as Example 6 except that the compression ratio was 92%.

A sheet-like thermally bonded nonwoven fabric was obtained by heat treatment and compression molding.

The obtained sheet-shaped thermally bonded nonwoven fabric had a thickness of 40 mm.

The apparent density was 56.3 kg/m''. The properties of this nonwoven fabric are shown in Table 1.

The nonwoven fabrics of Examples 1 to 5 in Table 1 develop latent crimp through heat treatment, so the repeated compression residual strain rate is as low as 8% or less, and the compression recovery rate is as high as about 61 to 69%. As is clear from the compressive stress of about 0.7 to 0.9 kg, it has appropriate flexibility.

The nonwoven fabric of Comparative Example 1 has the same thickness and the same apparent density as the nonwoven fabric of Example 3, but since latent crimp does not appear even after heat treatment, it fatigues quickly against compressive force and does not suffer from repeated compression residue. The strain rate is high at 8.2%, the compression recovery rate is also low at 56.0%, and the flexibility is poor.

The nonwoven fabric of Example 6 is a fiber with latent crimp.

It is made by mixing binder fibers and non-crimped fibers, but since it contains 60% by weight of fibers with latent crimp, latent crimp develops through heat treatment, resulting in moderate flexibility. have.

The nonwoven fabric of Comparative Example 2 is made of the same material as Example 6, but since only 20% by weight of fibers with latent crimp are mixed, there is little crimp developed by heat treatment and there is no residual strain due to repeated compression. The ratio is as high as 11.6%, and it cannot be used as a nonwoven fabric for cushioning materials.

The nonwoven fabric of Comparative Example 3 is also made of the same material as Example 6, but it has an extremely low apparent density of 8.7 kg/m', so it is soft and has a repeated compression residual strain rate of 8.9%.
This is so high that it cannot be used as a nonwoven fabric for cushioning materials.

The nonwoven fabric of Comparative Example 4 is also made of the same material as Example 6, but because the apparent density is too high at 56.3 kg/m'', the repeated compression residual strain rate is as high as 10.1%, making it difficult to use as a cushioning material. It cannot be used as a nonwoven fabric for other purposes.

(Effects of the Invention) The nonwoven fabric for cushioning materials of the present invention contains crimped fibers and binder fibers having a softening point lower than the melting point of the crimped fibers, and has excellent compression recovery properties. Excellent, low cyclic compression residual strain rate, suitable for furniture, vehicles,
It can be suitably used as a cushioning material for bedding and the like. and.

According to the manufacturing method of the present invention, the nonwoven fabric for cushioning material can be easily manufactured.

[Brief explanation of drawings]

Figure 1 is a diagram for explaining the method for determining compressive stress and compression recovery rate from the compression curve obtained in the compression test of nonwoven fabrics, and Figure 2 is a diagram for explaining the method for evaluating the thermoformability of nonwoven fabrics. It is. Room 1 supplies

Claims (3)

[Claims] (1) 30% to 99% by weight of fibers with latent crimp and 1% to 49% by weight of a binder having a softening point at least 20°C lower than the melting point of the latent crimp fibers; A nonwoven fabric for a cushion material, which is a compression-molded nonwoven fabric containing fibers, having an apparent density of 10 to 49 kg/m^3, and a repeated compression residual strain rate of 8% or less. (2) 30% by weight or more and 99% by weight of fibers with latent crimp
and 1% by weight or more and 49% by weight or less of binder fibers having a softening point at least 20° C. lower than the melting point of the latent crimp fibers, and the web is passed through the following manufacturing process A or B. 1. A method for producing a nonwoven fabric for a cushion material, which comprises heat-treating the nonwoven fabric for use in cushioning materials, and then taking out the formed nonwoven fabric after cooling to a temperature below the softening point of the binder fibers while maintaining the compressed state. Step A: The web is heated to a temperature at which the binder fibers soften and latent crimp occurs, and then compression molded at a temperature above the softening point of the binder fibers Step B: The web is heated at a temperature below the softening point of the binder fibers. A process in which the web is compressed and then heated while maintaining the compressed state to a temperature at which the binder fibers soften and latent crimp occurs. (3) A movable belt presser with a cooling function installed immediately after the heat treatment machine compresses the heated web and continuously cools it to below the softening point of the binder fibers while maintaining the compressed state. The method for producing a nonwoven fabric for cushioning material according to claim 2.