Anti-leakage non-woven fabric for foam molding

Abstract

The invention discloses an anti-leakage non-woven fabric for foam molding, which is characterized by comprising a first short fiber and a second short fiber, the first short fibers are bi-component short fibers; a waterproof layer is attached to the surface of the second short fiber. The present invention relates to an anti-leakage non-woven fabric for foam molding, which, when used as a reinforcing material for foam molding, has excellent performance in the aspect of following a mold, in particular, is capable of following a mold having depth irregularity, and is capable of suppressing the bleeding of a foam component in a foam molded body using such a mold.

Description

Technical Field

[0001] The invention relates to an anti-leakage non-woven fabric for foaming molding, belonging to the technical field of non-woven fabrics. Background Art

[0002] Polymer foam material is a kind of solid / gas composite material with a resin as the matrix and a large number of bubbles inside the material. It can be regarded as a solid / gas composite material with gas as the filling material. Foam material is light in weight, high in specific strength and has functions such as cushioning, sound absorption and heat preservation. It is widely used in yachts, high-speed railways, automobiles, packaging, aerospace, home appliances, wind turbine blades and other fields. Polyurethane foam material is used as a cushioning material for vehicle seats, etc. For example, an additional material such as a non-woven fabric layer is provided in the foam material of the vehicle seat cushion to prevent the stiffness of the cushion material from decreasing and to prevent the friction between the cushion material and the spring from generating noise.

[0003] When the foaming material is foamed, the non-woven fabric used for the reinforcement material is also pressed to match the shape of the foaming mold. Then the molded body is placed in the mold, the foaming components are poured, and the foaming is carried out under heat and pressure. When the foam is poured or foamed, the foam may penetrate the non-woven reinforcement material and seep out. Since the foamed body is used as a cushioning material for the vehicle seat, friction noise will be generated when the seeping foam rubs against the spring. Therefore, the reinforcement non-woven fabric needs to solve the problem of wine seepage.

[0004] As mentioned above, the reinforcing material nonwoven fabric is pressed into the mold shape of the foam body, and the reinforcing material nonwoven fabric is required to have high ductility, so that it is made to match the shape of the foam body mold during compression molding. It is necessary to have a foaming molded body with an uneven shape, and when preparing the foaming molded body, it is necessary to use a mold with an irregular depth. In this mold with an irregular depth, if the reinforcing material nonwoven fabric can not fully follow the mold, a foaming molded body with uniform thickness cannot be produced. And the reinforcing material nonwoven fabric can be partially thinned or torn. Therefore, it is necessary to prepare a nonwoven fabric that can cope with the occurrence of partial thinning or tearing of the reinforcing material nonwoven fabric when having an irregular mold. Summary of the invention

[0005] The purpose of the present invention is to provide a leakage-proof nonwoven fabric for foam molding, so that the nonwoven fabric will not be partially thinned or torn when used as a reinforcing material, and can also well prevent the leakage of foaming components in a deeply uneven mold.

[0006] To solve the above technical problems, the purpose of the present invention is achieved as follows:

[0007] The present invention relates to a leakage-proof nonwoven fabric for foam molding, which is characterized in that it comprises first short fibers and second short fibers; the first short fibers are bicomponent short fibers; and a waterproof layer is attached to the surface of the second short fibers.

[0008] On the basis of the above solution and as a preferred solution of the above solution: the second short fibers are waterproof short fibers.

[0009] On the basis of the above solution and as a preferred solution of the above solution: the first short fibers and the second short fibers are reinforced by needle punching.

[0010] On the basis of the above scheme and as a preferred scheme of the above scheme: the first short fiber is a core-sheath structure, including a core layer and a sheath layer, the core layer is a high melting point component, and the sheath layer is a low melting point component.

[0011] On the basis of the above scheme and as a preferred scheme of the above scheme: the weight ratio of the high melting point component to the low melting point component is 30-70:70-30.

[0012] On the basis of the above scheme and as a preferred scheme of the above scheme: the materials of the first short fibers and the second short fibers are polyester, polyethylene and polypropylene.

[0013] On the basis of the above scheme and as a preferred scheme of the above scheme: the length of the first short fiber and the second short fiber is 20-75 mm.

[0014] On the basis of the above scheme and as a preferred scheme of the above scheme: the weight mixing ratio of the first short fibers and the second short fibers is 20-80:20-80.

[0015] The beneficial effects of the present invention are as follows: the anti-leakage non-woven fabric for foam molding involved in the present invention, when used as a reinforcing material for foam molding, has excellent performance in following the mold, especially in being able to follow the mold with deep irregularities, and in the foam molded body using this mold, the seepage of the foam component can be suppressed. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with specific embodiments.

[0017] The present invention relates to a leakage-proof nonwoven fabric for foam molding, comprising a first short fiber and a second short fiber. The leakage-proof nonwoven fabric used as a reinforcing material is a nonwoven fabric formed by interweaving the first short fiber and the second short fiber. There is no particular restriction on the method of interweaving the first short fiber and the second short fiber, and a known nonwoven fabric production method can be applied. The first short fiber and the second short fiber can usually be reinforced by a needle punching method to form a nonwoven fabric.

[0018] The first short fibers are bicomponent short fibers, including a high melting point component and a low melting point component. The low melting point component melts after heating and partially bonds with other fibers to form a nonwoven fabric. In the leakage-proof nonwoven fabric used as a reinforcing material, when the leakage-proof nonwoven fabric is pressed and formed into a predetermined three-dimensional shape, the low melting point component in the first short fibers melts due to heating, thereby bonding with other fiber parts constituting the leakage-proof nonwoven fabric. Therefore, a stable three-dimensional shape can be formed.

[0019] The structure of the bicomponent staple fiber can be a core-sheath structure or a side-by-side structure. Further, in this embodiment, the bicomponent staple fiber is a staple fiber with a core-sheath structure, wherein the core is a high melting point component and the sheath is a low melting point component.

[0020] There is no particular restriction on the weight ratio of the high melting point component and the low melting point component in the bicomponent staple fiber. The weight ratio of the high melting point component and the low melting point component is generally 30-70:70-30. When the weight ratio is within this range, the ductility of the bicomponent staple fiber, especially the ductility at high temperature, is easier to follow the mold. Further, in this embodiment, it can be preferably 60:40.

[0021] In this embodiment, the low melting point of the low melting point component means that the melting point is lower than the temperature of compression molding, or the melting point is 90-150°C; the high melting point of the high melting point component means that the melting point is higher than the temperature of compression molding, or the melting point is 200-300°C.

[0022] The second staple fiber has at least a surface portion of a waterproof layer. There is no particular limitation on the method for forming the waterproof layer. Specific methods for forming the waterproof layer include, for example, performing a waterproof treatment after the first staple fiber and the second staple fiber are interwoven to form a nonwoven fabric. Alternatively, the waterproof staple fiber is used as the second staple fiber and interwoven with the first staple fiber to form a nonwoven fabric. The waterproof staple fiber is formed by performing a waterproof treatment on the staple fiber to form a waterproof layer on the fiber surface. The waterproof treatment can be performed by silicon treatment and fluorine treatment on the fiber or the nonwoven fabric.

[0023] There is no particular restriction on the material of the first staple fiber and the second staple fiber, and the material used can be polyester, polyethylene or polypropylene. In the present embodiment, polyester is selected as the material. And the first staple fiber and the second staple fiber can be of the same material or different materials. In addition, the high melting point component and the low melting point component used can be of the same material or different materials. The core and the sheath of the two-component staple fiber of the core-sheath structure can be of the same material or different materials. Specifically, in the present embodiment, the two-component staple fiber of the core-sheath structure is composed of high melting point polyester and low melting point polyester.

[0024] The length of the first staple fiber and the second staple fiber is usually 75 mm or less, but there is no particular limit on the length reduction, but it is usually 20 mm or more, preferably 30 mm. Within this length range, the entanglement of the first staple fiber and the second staple fiber can be increased, and the tensile length of the nonwoven fabric can be increased. The fiber fineness of the first staple fiber and the second staple fiber is 8 dTex or less, preferably 4 dTex or less. There is no particular limit on the lower limit of the fiber fineness, but it is usually above 3 dTex. The length or fineness of the first staple fiber and the second staple fiber can be the same or different.

[0025] The weight mixing ratio of the first short fibers and the second short fibers is 20-80:80-20; preferably 30-70:70-30, and more preferably 35-65:65-35. The upper and lower limits of the weight mixing ratio of the fibers can be any values ​​within the above numerical range. If there are too many first short fibers, the nonwoven fabric as an added material will adhere to the mold during the pressing process. If the first fibers are insufficient, the rigidity of the foamed material after press molding is insufficient, and the three-dimensional shape of the foamed body is unstable.

[0026] By configuring the above-mentioned first short fiber and second short fiber, the rate-free cloth as a reinforcing material has high ductility, especially ductility at high temperature, and has excellent formability in maintaining shape when heated and cooled. Specifically, in a high-temperature tensile test, the reinforcing material preferably has a strength of 100N / 5cm or less at 75% elongation, preferably 90N / 5cm or less. In addition, in a high-temperature tensile test, the reinforcing material preferably has a tensile strength of 60N / 5cm or more between 75% elongation and break, preferably 70N / 5cm or more, and more preferably 80N / 5cm or more. When the strength at 75% elongation and the difference between the strength at 75% elongation and the tensile strength are within the above range, the elongation at high temperature is high, and the possibility of exudation is small even in a mold with deep irregularities. "Strength and tensile strength at 75% elongation in a high-temperature tensile test" are values ​​measured by the method and conditions of a 140°C tensile test.

[0027] The strength of the reinforcing material at 5% elongation should be above 10N / 5cm, or above 15N / 5cm. When the strength at 5% elongation is within the above range, the reinforcing material is subjected to stamping. The "strength at 5% elongation" is tested by the method and conditions of the 25°C tensile test.

[0028] The strength at 75% elongation and the difference between the strength at 75% elongation and the tensile strength can be appropriately adjusted by the needling method on the mixing ratio of the two-component short fibers in the raw fiber, the needling density and the needle depth. For example, when the mixing ratio of the two-component short fibers in the raw fiber is increased, the strength at 75% elongation can be reduced, and the difference between the strength at 75% elongation and the tensile strength can be increased. In addition, when the needling density and the needle depth are adjusted by the needling method, the tensile strength can be increased, and the difference between the strength at 75% elongation and the tensile strength at break can be increased.

[0029] The nonwoven fabric as a reinforcing material may also include one or more other fibers in addition to the first staple fiber and the second staple fiber, as long as it does not interfere with the effect of the present invention. Examples of other fibers include known antibacterial fibers, flame retardant fibers, and hygroscopic heat-generating fibers. The blending ratio (by weight) of other fibers in the fiber raw material is generally 5 to 40%, preferably 10% to 30%. The upper limit and lower limit of the mixing ratio can be any value within the above numerical range.

[0030] The nonwoven fabric as the reinforcing material has a nonwoven fabric layer formed by interweaving the first and second short fibers. The reinforcing material may consist of only the nonwoven fabric layer, and may include other layers as long as it does not interfere with the effects of the present invention.

[0031] When the nonwoven fabric is used as a reinforcing material for foaming, there is no particular restriction on the material and type of the foaming material. In the present embodiment, it includes polyurethane. Specifically, the foaming material is a cushioning material, more specifically, a cushioning material for a vehicle seat. The foamed body is usually obtained by compression molding the reinforcing material to match the mold shape of the foamed body, arranging the molded body in the mold, pouring the foaming component, and then foaming the foaming component.

[0032] The foamed molded body is obtained by press molding the reinforcing material. In stamping molding, as long as the reinforcing material can be molded, there are no particular restrictions on the method and conditions. Stamping molding is usually performed using a mold. In addition, the press molding can be cold press molding (press molding for heating materials) or hot press molding (press molding for heating molds). Specifically, a method for obtaining a molded body can be obtained by, for example, comprising the steps of heating the main reinforcing material and press molding the heated main reinforcing material.

[0033] The raw materials used in this embodiment are:

[0034] (1) Bicomponent fiber

[0035] A bicomponent polyester fiber (fineness: 4.0 dTex, length: 5.1 cm) contains 50% by mass of a low-melting polyester (melting point: 110° C.) as a low-melting component and 50% by mass of a high-melting polyester (melting point: 260° C.) as a high-melting component.

[0036] (2) Waterproof fiber

[0037] Fibers (fineness: 2.0 dTex, length: 5.1 cm) obtained by coating high melting point polyester fibers (melting point: 260°C) with fluorinated oil and treating with water.

[0038] (3) Other fibers

[0039] High melting point polyester fiber (melting point: 260°C) (thickness: 2.0 dTex, length: 5.1 cm).

[0040] The raw material fibers consisting of (1) bicomponent fibers, (2) waterproof fibers and (3) other fibers are formed into a cotton web by a carding machine. The cotton web layers are cross-laminated by a web laying device to form a laminated web. By needle-punching the laminated web and interweaving the above fibers, a reinforcing material for a needle-punched nonwoven fabric, i.e., a needle-punched nonwoven fabric, is produced. Table 1 shows the blending ratio (weight standard) of (1) bicomponent fibers, (2) waterproof fibers and (3) other fibers.

[0041] The evaluation method is:

[0042] A.Thickness, weight, density

[0043] The thickness and gram weight of the actual sample and the comparative sample were measured. In addition, the air permeability of the actual sample and the comparative sample was measured according to the test conducted according to the JIS L1906 method. The results are shown in Table 1.

[0044] B. Tensile test

[0045] The properties of the reinforcement material were tested using a tensile testing machine at 25°C and 140°C. The results are shown in Table 1.

[0046] The tensile test at 25°C was carried out according to the following procedure. A rectangular specimen with a length of 200 mm and a width of 50 mm was cut out from the reinforcement of the physical sample and the comparative sample. As the test piece, the flow direction of the manufacturing process (hereinafter referred to as the "MD direction"). The specimen, its longitudinal direction (tensile direction) and the direction perpendicular to the MD direction (hereinafter referred to as the "CD direction"). Prepare each specimen so that the longitudinal direction is achieved. A chuck with a width of 20 mm is connected to each end of the specimen, and the gauge length is set to 100 mm. The tensile test was carried out at a tensile speed of 100 mm / min, and the tensile strength (N / 50 mm) when the specimen was elongated by 5%, 30%, 50%, 75% and 100% was measured, and the tensile strength at break (N / 50 mm) and elongation at break (mm) were measured. The tensile test in the MD direction was carried out 3 times, the tensile test in the CD direction was carried out 3 times, and a total of 6 tensile tests were carried out. The arithmetic average of the 6 measured values ​​was used as the tensile strength (maximum load) and elongation at break for each time. When the gauge length before the test is L0 (=100 mm) and the gauge length after rupture (elongation at break) is L, the elongation φ (%) is calculated as φ={(L-L0) / L0}×100.

[0047] The tensile test was carried out at 140°C according to the following procedure. A rectangular specimen with a length of 200 mm and a width of 50 mm was cut from the reinforcement of the physical sample and the comparative sample by the same method as the 25°C tensile test. Two heating clamps with a pair of clamping parts and a width of 25 mm were prepared. The two heating clamps were placed side by side and fixed with a fixture so that they would not be separated from each other. The total width of the clamping part was 50 mm. When the cushion seat was glued to the inner side of the clamp part and the pair of clamp parts were closed, the pair of clamp parts did not contact, and a gap of 3 mm to 5 mm was formed between the pair of clamps. Two curling rods were raised to 140°C, the center of the specimen was clamped in the tensile tester, and kept for 10 seconds. As mentioned above, since the total width of the kneading part was 50 mm, the specimen was also heated to a width of 50 mm. In addition, since there was a gap between the pair of clamps, each clamp part of the curling iron did not contact the specimen. After 10 seconds, a tensile test was conducted using the same method and conditions as the 25°C tensile test (excluding the force at 5% elongation) while the test piece was clamped.

[0048] C. Waterproof test

[0049] The test was conducted according to "JIS L1092 spray test". The number of tests for each example and comparative example was N=3.

[0050] D. Sponge exudation evaluation

[0051] The reinforcement materials of the real sample and the comparative sample are press-molded to match the mold shape for the foamed molded body (compatible with the shape of the back of the front seat of the car near the headrest support mounting part). Thereafter, the molded reinforcement material is placed in the mold for the foamed molded body, the polyurethane as the foaming component is poured, and the foaming component is foamed under heat and pressure to produce the real sample and the comparative sample of the foamed molded body, that is, the cushioning material. The manufactured foamed molded body (N=5) was visually inspected to see if there was any oozing on the back of the reinforcement material. In addition, the foamed molded body was placed on the rear side of the front seat of the car near the headrest support mounting part, and the squeaking sound was confirmed by pressing the hand or body of a person on the foamed molded body. These results are shown in Table 1.

[0052] Table 1 Test results of properties of nonwoven fabrics as reinforcement materials

[0053]

[0054]

[0055] In Table 1, “-” indicates that the elongation of some specimens was less than 100%, and therefore there was no measurement result of “100% tensile load”.

[0056] As can be seen from Table 1, in the reinforcement of the example, polyurethane impregnation was not observed on the back side and no squeaking sound of the spring was generated. On the other hand, in the reinforcement of the comparative example, polyurethane impregnation was observed on the back side and the spring made a squeaking sound when placed on a vehicle as a cushioning material. In addition, the waterproof level was lower than that of the example. These results show that the reinforcement of the physical sample is excellent in suppressing the exudation of the foaming component.

[0057] In addition, it can be seen from Table 1 that the reinforcing material has lower elongation strength, high tensile strength and elongation, and excellent ductility at both room temperature (25°C) and high temperature (140°C) compared with the reinforcing material of the comparative example. In particular, in the reinforcement of the physical sample, the 75% elongation strength in the high temperature (140°C) tensile test is lower than that of the control example, while the 75% elongation strength is significantly different from the tensile strength in the high temperature tensile test (Example: 91.9N / 5cm, Comparative Example: 49.7N / 5cm). This result shows that the reinforcing material of the specimen has excellent performance in terms of heating formability and shape retention during cooling, and therefore, has excellent performance in tracking a mold with deep irregularities.

[0058] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A leakage-proof nonwoven fabric for foam molding, characterized in that: It comprises a first short fiber and a second short fiber; the first short fiber is a bicomponent short fiber; and a waterproof layer is attached to the surface of the second short fiber.

2. The anti-leakage nonwoven fabric for foam molding according to claim 1, characterized in that: The second short fibers are waterproof short fibers.

3. The anti-leakage nonwoven fabric for foam molding according to claim 1, characterized in that: The first short fibers and the second short fibers are reinforced by needle punching.

4. The anti-leakage nonwoven fabric for foam molding according to claim 1, characterized in that: The first short fiber is a core-sheath structure, including a core layer and a sheath layer, the core layer is a high melting point component, and the sheath layer is a low melting point component.

5. The anti-leakage nonwoven fabric for foam molding according to claim 4, characterized in that: The weight ratio of the high melting point component to the low melting point component is 30-70:70-30.

6. The anti-leakage nonwoven fabric for foam molding according to claim 1, characterized in that: The materials of the first short fibers and the second short fibers are polyester, polyethylene and polypropylene.

7. The anti-leakage nonwoven fabric for foam molding according to claim 1, characterized in that: The lengths of the first short fibers and the second short fibers are 20-75 mm.

8. The anti-leakage nonwoven fabric for foam molding according to claim 1, characterized in that: The weight mixing ratio of the first short fibers to the second short fibers is 20-80:20-80.

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