JP2010174393A - Urethan-reinforcing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a urethane-reinforcing material without developing gaps or the blooming of a foaming agent by getting used to a deformation range in the process of foaming, without causing a squeaking noise even bonded with a bottom receiving spring when being used as a cushion, and easily molded as one unit without requiring a cutting process or pre-molding process on molding. <P>SOLUTION: The urethane-reinforcing material is a stretchable nonwoven fabric consisting mainly of crimping conjugated short fibers, and having the characteristics of 80-300 g/m<SP>2</SP>unit weight, 1.0-15.0 N/5 cm 50% tension stress, and 100% or more of elongation at break. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is disposed at the bottom of a foamed molded product such as polyurethane used as a cushioning material for vehicle seats, etc., and prevents abnormal noise generated by friction between the polyurethane foam and the spring material. The present invention relates to a urethane reinforcing material that prevents bleeding and has an excellent reinforcing effect.

  Foam molded products such as soft polyurethane foam are generally used as cushioning materials for vehicle seats, etc., and the bottom of such foam molded products generates a squeak noise when in direct contact with a seat spring, resulting in local stress. In order to avoid damage and damage, a reinforcing material is usually provided.

  Conventionally, such a reinforcing material is a combination of cold chill and slab urethane, or a coarse blanket. The slab urethane is placed in contact with the foam molding die surface, and after the cold chill is placed inside, the urethane liquid is injected. However, it was produced as a polyurethane foam in-mold foam-molded product with a reinforcing layer backed by heating and pressurizing and foaming.

However, since there was a difficulty that the cold chill was difficult to follow the molded shape of the molded product, the use of a nonwoven fabric as a reinforcing fabric was developed and used, and the basis weight formed with fibers having a fiber diameter of 2 to 20d. and 40~70g / m bulky substrates ² coarse, is formed by fibers having a fiber diameter 2～10D, reinforcements basis weight consisting of a thin dense nonwoven 40 and 80 g / m ² (see Patent Document 1) and, applying a spunbonded nonwoven fabric or the like porosity from 90 to 94% of the bulky nonwoven fabric and the upper and lower layer basis weight 30 to 200 g / m ^2, the basis weight at 20 to 100 g / m ² porosity of 87 to 91% Reinforcing material in which a dense nonwoven fabric is laminated and integrated as an intermediate layer (see Patent Document 2), and further comprises a crimped continuous fiber and is partially thermocompression bonded to a basis weight of 50 to 200 g / m ² and a thickness of 0.5 to 2 0.0 mm non-woven reinforcing material (see Patent Document 3) Such as by laminating a short fiber web on fabric consisting tape yarn reinforcements laminated and integrated by needle punching (see Patent Document 4) have been proposed.

JP-A-6-136651 JP-A-6-171003 JP 2000-62061 A JP 2000-94457 A

  However, each of the reinforcing materials according to the above proposals has a certain effect, but there is a problem with large deformation of the irregularities in the molding process of urethane foam, and the correspondence is different, for example, the spunbond method The non-woven fabric base fabric made of the above is inferior in deformation followability, so it can be handled by cutting. In the case of the short fiber structure having relatively good deformation followability, the base fabric is molded before foaming urethane, and then foamed urethane. At present, the molding process is performed.

  In view of the actual situation as described above, the present invention has a urethane reinforcement that can be integrally molded at one time without the need for a cutting or pre-molding process at the time of molding, especially in the molding process of urethane foam, without foaming out of the foamed urethane. The purpose of this project is to develop a material to find a material and to provide a reinforcing material suitable for it.

That is, the present invention suitable for the above object is a non-woven fabric mainly composed of crimped composite short fibers, and has a weight per unit area of 80 to 300 g / m ² and a 50% elongation stress of 1.0 to 15. It is characterized by having a property of 0.0 N / 5 cm and a breaking elongation of 100% or more.

  Here, the crimped composite short fiber used in the present invention is preferably a composite short fiber composed of 60/40 to 40/60 of a high melting point component and a low melting point component of a polyester resin. In addition, you may mix other short fibers, such as a part water-repellent short fiber.

  When the reinforcing material of the present invention is used so as to be in contact with the surface of the foam molding die, when the urethane stock solution is injected and heated and pressurized for foaming, the foaming liquid does not bleed out and causes partial elongation when mounted on the die. In addition, it fits into the deformation area of the unevenness in the process of foaming, has good gripping properties, does not cause the displacement of the nonwoven fabric, and produces a squeak noise even when directly contacting the seat receiving spring when used as a seat cushion. Not only does this occur, but when the weight per unit area is low, mixing of water-repellent short fibers prevents the occurrence of seepage of the urethane liquid and has the effect of improving wear. In addition, there is no need for cutting or pre-molding when molding, and an implementation effect is also expected that enables stable integral molding at once.

Hereinafter, specific embodiments of the reinforcing material of the present invention will be described in detail. The reinforcing material of the present invention is a non-woven fabric mainly composed of crimped composite short fibers as described above, and has a weight per unit area of 80 to 300 g / m ² and a 50% elongation stress of 1.0 to 15.0 N / It is composed of a stretchable nonwoven fabric having the characteristics of 5 cm and elongation at break of 100% or more. In these cases, the crimpable composite short fiber as the main material is not necessarily limited to the same type of fiber, and may be a mixed fiber of different types of crimped composite short fibers. There is no limit. However, when water-repellent short fibers and the like are mixed, the mixing ratio is preferably in the range of 3/97 to 40/60. The basis weight range is in the range of 80 to 300 g / m ^2. However, when other short fibers such as water-repellent short fibers are included, a low basis weight range of 80 to 120 g / m ² is sufficient. , Have an effect. Hereinafter, each element of the above configuration will be described in turn.
(1) Crimpable composite short fiber The crimpable composite short fiber, which is the main material of the reinforcing material of the present invention, is a composite fiber of polyester, nylon, polyethylene, and polypropylene with a high melting point component and a low melting point component. Although it is possible, blending by a combination of a high melting point resin of a polyester resin and a modified low melting point polyester resin is particularly suitable, and a combination blending by a melting point difference of the modified low melting point resin is also possible. Specific examples include composite fibers of a polyester resin (melting point of about 270 ° C.) and a low melting point polyester resin (melting point difference of about 20 to 100 ° C.).

  These are usually composite fibers with a side-by-side, eccentric core-sheath structure, and the blending ratio of the high melting point component and the low melting point component is preferably in the range of 60/40 to 40/60, and the fineness of the fiber is 1.0 to A range of 10.0 decitex (dtex) is preferred. If the fineness is less than 1 dtex, the fiber layer becomes dense, and if it exceeds 10 dtex, the fiber layer becomes coarse.

In addition, when a single-component short fiber other than the short fiber, for example, a water-repellent short fiber to be described later, is mixed with the crimped composite short fiber, the crimp development property and crimp characteristics are reduced by the amount of the mixed fiber. Since there is a tendency, it is necessary to select the ratio according to the crimp characteristic for the fiber mixing ratio.
(2) Water-repellent short fibers for blended fibers Next, the water-repellent short fibers blended into the crimped composite staple fibers as necessary are fibers obtained by subjecting a normal fiber made of polyester resin to a water-repellent treatment with silicon or fluorine. And the treatment causes the fibers to exhibit a low coefficient of friction. Therefore, the degree of water repellency can be replaced by the coefficient of friction, and the range is usually about 0.05 to 0.20.

In this case, the fineness of the water-repellent short fibers is preferably in the range of 1.0 to 10.0 decitex (dtex) like the crimped composite short fibers. In addition, in order to impart water repellency to the nonwoven fabric constituting the reinforcing material, it is necessary to consider the mixing ratio of the water-repellent short fibers exhibiting the low friction coefficient, and the mixing ratio is usually in the range of 3 to 40% by mass. The amount is preferred. If the amount of mixed fibers is less than 3% by mass, the water repellency of the folded non-woven fabric will be reduced, so that it will be difficult to prevent the urethane from seeping out. Although the effect is sufficient, the stress at the time of 50% elongation of the nonwoven fabric characteristic as a reinforcing material is 1.0 or less, the moldability is deteriorated, and it is not preferable from the viewpoint of cost.
(3) Preparation of non-woven fabric As described above, the main component of the crimped composite short fiber or the mixed staple fiber of different types of crimped composite fiber is mixed with the water-repellent short fiber as necessary. A non-woven fabric used as a base material is prepared. In preparing the nonwoven fabric, a carding process is applied to the above-mentioned crimped composite short fiber or a staple fiber mixed with different types of crimped composite short fibers. After the web is entangled between the fibers by needle punching, the crimped composite short fiber is crimped by continuously heat-treating it through a heat treatment machine (causing web shrinkage). Then, the required stretchable nonwoven fabric in which crimps are expressed is obtained by adjusting the thickness of the nonwoven fabric through a heat roll.

Here, as the basis weight by weight of the nonwoven fabric good range of 80~300g / m ² as described above, when the basis weight mass is less than 80 g / m ^2, there is no problem in molding, but exudation of urethane foam resin Even if mixed with water-repellent short fibers that are effective in preventing this, the effect cannot be obtained, which is not preferable. In addition, in the case of a crimpable composite short fiber that hardly contains other short fibers, the basis weight range is 100 to 300 g / m ² , which is effective, but a part of the crimpable composite short fiber is water-repellent. In the case of mixing fibers and the like, the mixing ratio of the fibers is limited to 3 to 40% by mass, but the basis weight range is 80 to 120 g / m ² , which is sufficiently effective.
(4) Properties of the nonwoven fabric The nonwoven fabric obtained as described above is considered to have properties suitable for use as a reinforcing material. In the nonwoven fabric mainly composed of the crimped composite short fibers, the mass per unit area is 80 g / In the range of m ^{2 to} 300 g / m ² , it is important to have characteristics that 50% elongation stress is 1.0 to 15.0 N / 5 cm and elongation at break is 100%.

  When the 50% elongation stress of the nonwoven fabric is less than 1.0 N / 5 cm, in order to mold urethane foam, the nonwoven fabric is attached to the mold, the urethane foam liquid is injected, and the nonwoven fabric is attached in the molding process. Occasionally partial elongation causes poor handling, and in the process of urethane foaming during mold processing, the gripping property of the deformation area of the concaves and convexes is deteriorated, and the nonwoven fabric is liable to be displaced. If the stress exceeds 15.0 N / 5 cm, there is no problem in the handling property of mounting on the mold, but it is not preferable because the deformation of the unevenness becomes insufficient in the process of urethane foaming in the mold processing and the resulting uneven shape is deteriorated. . Also, the breaking elongation of the nonwoven fabric should be 100% or more, and if the breaking elongation of this nonwoven fabric is less than 100%, non-uniform deformation is likely to occur due to deformation of the entire nonwoven fabric and partial deformation of the unevenness in mold processing. Therefore, it is not preferable. Examples of the present invention will be described below together with comparative examples.

Example 1
90% by mass of polyester / low-melting polyester composite fiber with a fineness of 2.2 decitex and a fiber length of 51 mm (melting point of the low-melting polyester: 250 ° C.), and a polyester / low-melting polyester composite with a fineness of 2.2 dtex and a fiber length of 51 mm Fiber (melting point of low-melting polyester: 232 ° C.) 10% by mass of short fibers are uniformly mixed (weight per unit area: about 70 g / m ² ), then carded, needle depth of 10 mm, number of driven 110 / A cm ² needle was processed, and subsequently a crimping treatment was continuously performed with a heat treatment machine at a temperature of 170 ° C. and a residence time of 30 seconds. The obtained non-woven fabric was highly stretchable and had a mass per unit area of 101 g / m ² and a thickness of 0.76 mm.

Example 2
Polyester / low-melting polyester composite fiber with a fineness of 2.2 decitex and a fiber length of 51 mm / low-melting polyester composite fiber (melting point of the low-melting polyester: 250 ° C.) 30% by mass, and a polyester / low-melting polyester composite with a fineness of 2.2 dtex and a fiber length of 51 mm Fiber (melting point of low melting point polyester: 232 ° C.) 70% by mass of short fibers are uniformly mixed (weight per unit area: about 70 g / m ² ), then carded, needle depth of 10 mm, number of driven 120 / A cm ² needle was processed, and subsequently a crimping treatment was continuously performed with a heat treatment machine at a temperature of 160 ° C. and a residence time of 30 seconds. The obtained non-woven fabric was highly stretchable and had a mass per unit area of 107 g / m ² and a thickness of 1.04 mm.

Example 3
A polyester / low-melting polyester composite fiber having a fineness of 2.8 decitex and a fiber length of 51 mm (low-melting polyester melting point: 250 ° C.) 95% by mass, and a surface of the fiber length of 51 mm was coated with silicon at a fineness of 2.2 decitex Polyester fiber (melting point: 262 ° C.) having a friction coefficient μs between the fibers of 0.151 (melting point: 262 ° C.) 5% by mass (basis mass: 66 g / m ² ) is uniformly mixed and carded, and then the needle depth Was 10 mm and the number of driven needles was 110 / cm ² , and subsequently a crimping treatment was continuously performed with a heat treatment machine at a temperature of 170 ° C. and a residence time of 30 seconds. The obtained non-woven fabric was highly stretchable and had a mass per unit area of 107 g / m ² and a thickness of 1.00 mm.

Example 4
90% by mass of polyester / low-melting polyester composite fiber with a fineness of 2.2 decitex and a fiber length of 51 mm (melting point of the low-melting polyester: 250 ° C.), and a polyester / low-melting polyester composite with a fineness of 2.2 dtex and a fiber length of 51 mm Fiber (melting point of low-melting polyester: 232 ° C.) 10% by mass of short fibers are uniformly mixed (weight per unit area: about 100 g / m ² ), then carded to give a needle depth of 10 mm, and the number of driven 120 / cm The needle processing of No. ² was performed, and subsequently, a crimping treatment process was performed with a heat treatment machine at a temperature of 170 ° C. and a residence time of 30 seconds. The obtained non-woven fabric was highly stretchable and had a basis weight of 141 g / m ² and a thickness of 1.01 mm.

Example 5
90% by mass of polyester / low-melting polyester composite fiber with a fineness of 2.2 decitex and a fiber length of 51 mm (melting point of the low-melting polyester: 250 ° C.), and a polyester / low-melting polyester composite with a fineness of 2.2 dtex and a fiber length of 51 mm Fiber (melting point of low-melting polyester: 232 ° C.) 10% by mass of short fibers are uniformly mixed (weight per unit area: about 146 g / m ² ), then carded to give a needle depth of 10 mm, and the number of driven wires is 110 / cm The needle processing of No. ² was performed, and subsequently, a crimping treatment process was performed with a heat treatment machine at a temperature of 170 ° C. and a residence time of 30 seconds. The obtained non-woven fabric was highly stretchable and had a mass per unit area of 204 g / m ² and a thickness of 2.13 mm.

Comparative Example 1
50% by mass of polyester / low melting point polyester composite short fiber having a fineness of 2.2 dtex and a fiber length of 51 mm (melting point of low melting polyester: 250 ° C.), and a fiber having a fineness of 2.2 dtex and a fiber length of 51 mm coated with silicon -Polyester fiber (melting point 262 ° C) having a coefficient of friction between fibers of 0.151 (melting point 262 ° C) 50% by mass (weight per unit mass 42g / m ² ) is uniformly mixed and carded, and then at the needle depth Needle processing was performed to 10 mm and the number of driven electrodes was 110 / cm ² , and subsequently, crimping treatment was continuously performed with a heat treatment machine at a temperature of 170 ° C. and a residence time of 30 seconds. The obtained non-woven fabric was highly stretchable and had a mass per unit area of 65 g / m ² and a thickness of 0.59 mm.

Comparative Example 2
90% by mass of polyester / low-melting polyester composite fiber with a fineness of 2.2 decitex and a fiber length of 51 mm (melting point of the low-melting polyester: 250 ° C.), and a polyester / low-melting polyester composite with a fineness of 2.2 dtex and a fiber length of 51 mm Fiber (melting point of low-melting polyester: 232 ° C.) 10% by mass of short fibers are uniformly mixed (weight per unit area: about 271 g / m ² ), then carded to give a needle depth of 10 mm, and the number of driven 120 / cm ² Subsequently, the crimping treatment was performed continuously with a heat treatment machine at a temperature of 170 ° C. and a residence time of 50 seconds. The obtained non-woven fabric was highly stretchable, the basis weight was 382 g / m ² , and the thickness was 3.30 mm.

Comparative Example 3
A nonwoven fabric A is obtained by preliminarily thermocompression bonding a web having a basis weight of 72 g / m ² made of polyester fiber having a fineness of about 3.0 dtex manufactured by the spunbond method by carding with a hot roll at 170 ° C. It was. Similarly, a nonwoven fabric B was obtained by preliminarily thermocompression bonding a web having a weight per unit area of 40 g / m ² by calendering with a 200 ° C. hot roll. The obtained non-woven fabrics A and B were laminated, and needle processing was performed at a needle depth of 14 mm and the number of driven 50 / cm ² to obtain a laminated non-woven fabric. The obtained nonwoven fabric had a basis weight of 114 g / m ² and a thickness of 1.20 mm.

  For each nonwoven fabric obtained by the above examples and comparative examples, urethane foam resin is injected and added according to a conventional method, and foam molding is performed. The obtained molded product exudes to the sample surface of the polyurethane resin and observes the adhesion state. The evaluation was determined. The results are shown in Table 1 below. In the evaluation, each sample, characteristics, and exudation of foamed urethane were evaluated according to the following measurement method.

Measurement method Weight per unit area: g / m ²
A 500 mm × 500 mm sample piece is cut out from the sample, and the mass is measured to a unit of 0.1 g. The mass is quadrupled and expressed in g / m ² . The average value of N = 3 (measured three times) is rounded off and expressed as an integer.

Thickness: mm
A 50 mm × 50 mm sample piece was cut out from the sample, measured at three points with a dial gauge having a contact area of 5 cm ² and a pressing pressure of 20 g, and expressed in mm. The average value of N = 3 is rounded off to the nearest decimal point.

Friction coefficient of short fiber: μs
Measured in accordance with JIS standard JIS L1015-8.13.

Measuring instrument: Radar friction tester Cylinder outer diameter: 8mm
Instrument: Torsion balance 靜 Friction coefficient (μs) = 0.733log (W / (W-m))
W: Load applied to both ends of the fiber (N)
m: Reading of torsion balance (N)
Tensile strength at break n = 3 samples of 5 cm × 30 cm are taken in both the longitudinal and transverse directions. Using Tensilon manufactured by Toyo Bald-In Co., Ltd., the tensile strength at break was measured at a gripping interval of 20 cm and a pulling speed of 20 cm / min, and expressed as an average value.

50% elongation stress: N / 5cm
N = 3 samples of 5 cm × 30 cm are taken in both the vertical and horizontal directions. Using Tensilon manufactured by Toyo Bald Inn Co., Ltd., the stress at the 10 cm point was measured at a gripping interval of 20 cm and a pulling speed of 20 cm / min, and expressed as an average value.

Evaluation of seepage of urethane foam Set a sample in a mold for foam molding (including some irregularities), add urethane foam as usual, and perform polyurethane foam molding under heat and pressure to form a flexible polyurethane foam. An in-mold foam molded product was created. The obtained molded article oozed out to the sample surface of the polyurethane resin and observed the adhesion state, and the following evaluation was determined.

Uniform deformation of the non-woven fabric on the uneven surface of the sample, no bleeding, no adhesion problems ○
The sample does not exude, but the uneven nonwoven fabric does not deform uniformly △
The deformation of the non-woven fabric of the uneven part of the sample is uniform, but there is a seepage.
The deformation of the uneven nonwoven fabric of the sample is non-uniform and oozes out. ×

Claims (2)

A non-woven fabric mainly composed of crimped composite short fibers, having a weight per unit area of 80 to 300 g / m ² , a 50% elongation stress of 1.0 to 15.0 N / 5 cm, and a breaking elongation of 100%. A urethane reinforcing material having the characteristics described above.   The urethane reinforcing material according to claim 1, wherein the crimpable composite short fiber is a composite short fiber comprising a blend of 60/40 to 40/60 of a high melting point component and a low melting point component of a polyester resin.