JPH0146625B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a material that has both rigidity and shielding properties that can be deep drawn and is useful as an interior material for automobile ceiling materials, door trims, rear shells, seat bags, trunk parts, etc. The present invention relates to a method for manufacturing nonwoven fabric. [Prior art] Conventionally, the above-mentioned interior materials include resin felt made of phenol-aldehyde condensation resin filled with fibers,
Materials that can withstand temperatures of over 100°C are used, such as foamed synthetic resin, polypropylene composites, and polypropylene cardboard. Among these materials, resin felt has excellent rigidity, heat-resistant shape retention, dimensional stability, and shielding properties, but has the drawbacks of poor moldability, impact resistance, and lightness. Furthermore, polypropylene cardboard has excellent rigidity and light weight, but on the other hand, it is poor in deep drawing, and because it uses a corrugated member, its strength is directional. Furthermore, foamed synthetic resins such as polystyrene are excellent in lightness, but have the drawbacks of poor moldability and bending resistance, and also have problems with appearance after molding.
No material has been obtained that satisfies all of the performance requirements for interior materials, namely, rigidity, appropriate flexibility, lightness, dimensional stability, heat-resistant shape retention, and moldability. On the other hand, fibers such as polyethylene, polypropylene, and low contact point (140℃) polyester are used as a fiber binder, and a fiber mat made of synthetic fibers is needled to temporarily bind the fibers of the upper and lower layers of the web, and then heated. Melting the above fiber binder,
Methods for producing resilient nonwoven fabrics by bonding other synthetic fibers are known. Although this nonwoven fabric is lightweight and flexible, it lacks moldability and rigidity, so it is useful as an interior material for flat areas, but is not useful as an interior material for areas with complex shapes. In addition, needle punched cloth has a softening point of 100 to 130℃.
After coating or impregnating an aqueous emulsion of a thermoplastic resin, the nonwoven fabric is heat-dried to remove moisture, and the nonwoven fabric is further heated and press-molded to obtain an automobile interior material. be. This interior material has the advantage that it can be installed in places with complex shapes. The fixation of the fibers of this nonwoven fabric is due to the entanglement of the fibers by needle punching and the adhesion of the emulsion resin to the fibers, but the apparent density of the nonwoven fabric to which the emulsion is applied and impregnated is 0.08~
Since it is bulky at 0.13 g/cm ² , it has the disadvantage that the filling effect with emulsion resin is poor. Furthermore, since the filling effect is insufficient, there is a drawback that the shielding performance is inferior. The present inventor first developed a method for producing a nonwoven fabric using thermoplastic resin to overcome the drawbacks of poor dimensional stability and rigidity of the latter moldable nonwoven fabric without reducing its lightness, heat-resistant shape retention, and air permeability. After needling a fiber mat consisting of 15 to 50% by weight of binder fibers and 85 to 50% by weight of synthetic fibers or natural fibers having a melting point 40°C or more higher than the melting point of the thermoplastic resin, the mat is The thermoplastic resin binder fibers are heated at a temperature that melts the thermoplastic resin binder fibers but not the synthetic fibers or the natural fibers, and then the thermoplastic resin binder fibers are heated while the thermoplastic resin binder fibers remain in the molten state. Compress the fiber mat to reduce the apparent density of the mat
An aqueous emulsion of thermoplastic resin with a moldable temperature range of 80 to 180°C is adjusted to 0.15 to 0.50 g/cm ² and added to the compressed fiber mat in a proportion of the resin hardness of the emulsion to the fiber weight of the fiber mat. The type is
Provided is a method for producing a moldable nonwoven fabric, characterized in that the nonwoven fabric is obtained by coating or impregnating it to a concentration of 15 to 300% by weight, and then heating and drying at 60 to 250°C to remove moisture. 1986-87353). This method uses a combination of a thermoplastic fiber binder and a resin emulsion to improve the rigidity of the nonwoven fabric, as well as bonding the fibers together to improve dimensional stability. A major feature of this method is that it compresses and expels a portion of the air, making it possible to increase the filling rate of the emulsion resin into the mat, thereby improving the rigidity of the nonwoven fabric. However, although this moldable nonwoven fabric has excellent moldability, dimensional stability, air permeability (sound absorption), and improved rigidity, it has poor water shielding properties due to its air permeability. Furthermore, depending on the application, higher rigidity,
Some require water impermeability. We previously proposed a carpet made of resin-backed nonwoven fabric with a foam sheet adhered to the back side as a material with excellent water impermeability and rigidity. (Akira Jigan
(See Nos. 57-170656 and 57-195731) However, this method requires a backing layer formation step and a foam sheet bonding step, and
In order to prevent the foam sheet from breaking due to bending, it is necessary to further laminate a non-foam sheet to the foam sheet. Furthermore, since the resin layer directly forms the surface layer, there are problems in terms of appearance. [Specific means for solving the problems] The present invention was made with the aim of improving the performance of the laying material proposed above, that is, improving shielding performance, improving rigidity, and improving appearance. This problem has been solved by combining expandable resin particles such as expandable polystyrene resin particles, an aqueous resin emulsion, and a nonwoven fabric as a backing material. That is, as shown in FIG. 1, the emulsion is made by superimposing a nonwoven fabric 2 made of a thermoplastic resin fiber binder with a melting point of 60 to 200°C and a basis weight of 6 to 200 g/m ² on the surface of a nonwoven fabric 1 for the lower layer. On top of this, foamable thermoplastic resin particles 3 are placed, and on top of this, nonwoven fabric 4 for the upper layer is placed.
are superimposed to form a laminate 5 having a structure in which expandable thermoplastic resin particles are sandwiched between the nonwoven fabric for the upper layer and the nonwoven fabric for the lower layer, this laminate is needle punched to intertwine the upper and lower layers, and then the needle Provided is a method for producing a laying material, which comprises applying and impregnating a punched nonwoven fabric laminate with an aqueous resin emulsion, and then heating the applied surface to foam the expandable thermoplastic resin particles and drying the aqueous resin emulsion. It is something to do. (Nonwoven fabric) As the nonwoven fabric as the rug material in the present invention, needle punch carpets made from natural and resin fibers such as wool, nylon, polyacrylonitrile, polyacetate, and polypropylene are used. This needle punch carpet is a web obtained by needling a fiber mat made of synthetic fibers and/or natural fibers, and is manufactured by a known nonwoven fabric manufacturing method. i.e. 1.2~300
Thoroughly mix fibers with denier and fiber length of 25 to 150 mm.
The opened fibers are fed to a web forming device, and the web (fiber mat and/or this web) obtained by stacking the cards formed from the mixed fibers to the desired fiber weight is vertically It is temporarily fixed by needling and intertwining the fibers. Moreover, non-woven fabrics that have not been needled can also be used. For example, the web itself obtained from the card may be used. If some of these fibers (15 to 50% by weight of fibers based on the weight of the pine) are replaced with a resin fiber binder having a low melting point of 80 to 200°C, the strength of the resulting laying material will be further improved. As such a fiber binder, short fibers (15 to 40 mm in length) of resin such as polyethylene, polypropylene, linear polyester, and low molecular weight co-condensed polyamide are used. The raw materials for the synthetic fibers constituting the fiber mat include polyethylene terephthalate, polyamide, etc., which have a melting point of 40% higher than the melting point of the thermoplastic resin fiber binder.
A thermoplastic resin having a melting point higher than 70°C, preferably 70°C or higher (specifically 200 to 280°C) is used. Further, as natural fibers, cotton, linen, wool, etc. are used. The basis weight of the nonwoven fabric for the upper layer is 100 to 1000 g/m ² , preferably 250 to 500 g/m ² , and the basis weight of the nonwoven fabric for the lower layer is 100 to 1000 g/m ² , preferably 300 to 750
g/ ^m2 . (Nonwoven Fabric of Fiber Binder) The nonwoven fabric 2 of thermoplastic resin fiber binder is made of polyethylene, polypropylene, linear polyester, polyamide, etc., with a melting point of 60 to 200°C, preferably 90 to 170°C, a denier of 2 to 12, and a fiber length of 2-8
6 to 200 g/m ² , preferably 20 to 60 g/m 2 obtained by intertwining resin fibers of mm in size by spunbonding method.
A breathable material with a basis weight of ^m2 , and a wall thickness of 5 to 500 mm.
It is micron. In addition, this fiber binder is made by melting pellets of resin such as polypropylene, polyester, polyamide, etc. using an extruder and extruding them in a continuous shape through a die with many thin holes, which is then carried by the wind so that the individual fibers do not converge. It may also be produced by pulling it out, depositing it on a screen below the die, and pulling it off with a winder. Such fiber binder nonwoven fabric has many gaps through which water can pass, and is manufactured by Diabond Industries Co., Ltd.
The product name of Meltron W is PAY-200 and PAS-200 for polyamide-based products, ES-500 for polyester-based products, and Y7 for ethylene-acetic acid copolymer-based products, manufactured by Mitsui Petrochemical Industries, Ltd. ), polypropylene-based ones are Syntex PK-
103, PK-106, PK-404, PK-408, etc. Polyethylene-based products are available under Admel's product names, and similar non-woven fabrics are available from Kureha Sen'i Co., Ltd.
DYNAC product name LNS-0000, LNS-2000,
It is sold with grade names such as ES-00, B-1000, B-2000, and B-3000. This fiber binder nonwoven fabric 2 is superimposed on the surface of the lower layer nonwoven fabric 1, and foamable resin particles 3 are placed on top of the nonwoven fabric 2 for lower layer.
are arranged in a layered manner, and the lower layer nonwoven fabric 4 is superposed on top of the lower layer nonwoven fabric 4 to form a laminate 5. By needling this laminate 5, the fibers of the upper and lower nonwoven fabrics become entangled, and the expandable resin particles are stably fixed. The presence of this fiber binder nonwoven fabric 2 prevents the foamable resin particles 3 from being buried in the fiber mat of the lower layer nonwoven fabric 1. That is, the wave of the nonwoven fabric for the lower layer obtained from the card is bulky and has a fiber density of 0.08 to 0.17 g/cm ³
Since the foamed resin particles are small, that is, have large gaps and are not flat, the foamable resin particles are buried in the fiber mat of the needle-punched nonwoven fabric and cannot be used effectively. In order to prevent this burying, a nonwoven fabric made of a fiber binder with a high fiber density of 0.08 to 0.2 g/cm ³ and fine fibers obtained by a spunbond method or the like is used. Of course, this fiber binder nonwoven fabric 2 may also be sandwiched between the foamable resin particles and the upper layer nonwoven fabric 4. The use of this fiber binder nonwoven fabric, like the low melting point fiber binder in the top and bottom nonwoven fabrics, melts and serves to fix the fibers. (Expansible thermoplastic resin particles) Expandable thermoplastic resin particles include those with a particle size of about 0.1 to 3 mm, such as expandable polystyrene, expandable α-methylene/styrene copolymer, expandable polyethylene, and expandable polypropylene. is used. Among these, expandable polystyrene particles having a particle size of 1.5 mm or less are preferred because they are inexpensive. If the particle size is large, handling becomes difficult, and
The laminate is easily destroyed during needling. The expandable resin particles 3 are preferably arranged in a layered manner as much as possible between the nonwoven fabrics 1 and 4, as shown in FIG. (Aqueous Resin Emulsion) As a backing material, an aqueous resin emulsion that functions as a backing material for fiber mats and for adhesion of foam particles is an aqueous emulsion of a resin having a glass transition point of -65°C to +150°C, such as polyvinyl acetate, Vinyl chloride/vinylidene chloride copolymer, styrene/
Butadiene copolymer rubber, styrene/methyl methacrylate copolymer, styrene/n-butyl acrylate copolymer, ethylene/vinyl acetate copolymer,
Latexes such as styrene/n-butyl acrylate/acrylic acid copolymer, vinylidene chloride/acrylonitrile/acrylic acid copolymer, and aqueous emulsions may be used alone or in mixtures. In terms of flexibility of the non-woven fabric layer of the laying material, aqueous resin emulsion or latex with a glass transition point of 20°C or lower is preferable; conversely, in order to impart rigidity and moldability to the non-woven fabric layer of the laying material, a glass transition point of 80°C is preferred. A resin/fat aqueous emulsion having a temperature of 0.degree. C. or higher is preferred. Aqueous emulsions with a glass transition point of 80°C or higher include (a). Poly n-propyl methacrylate (Tg 81℃), polystyrene (100℃), polyacrylonitrile (100℃), polymethyl methacrylate (105℃), polymethacrylic acid (130℃), polyitaconic acid (130℃), poly Acrylamide (153℃)
In addition to aqueous emulsions of homopolymers such as (b). 50 to 100% by weight, preferably 65 to 95% by weight of vinyl monomer, which is the raw material for these polymers, and other vinyl monomers such as 2-ethylhexyl acrylate (Tg - 85℃), acrylic acid n. Butyl (-54℃),
Ethyl acrylate (-22℃), isopropyl acrylate (-5℃), 2-ethylhexyl methacrylate (-5℃), n-propyl acrylate (8℃)
), n-butyl methacrylate (20℃), vinyl acetate (30℃), ethyl methacrylate (65℃), vinyl chloride (79℃), etc. or vinylidene chloride (-18℃), etc.
°C) Aqueous emulsion of a copolymer with 50% by weight or less, preferably 35 to 5% by weight It is the glass transition point of coalescence], (c). Resin aqueous emulsion with Tg +80-155°C 50-97% by weight, preferably 55-95
% by weight and 50 to 3% by weight, preferably 45 to 5% by weight of an aqueous resin emulsion having a Tg of -85°C to less than +80°C. The resin solid content concentration of aqueous emulsion is usually 20~
60% by weight, and the diameter of the dispersed resin particles is
It is 10μ (microns) or less, preferably 0.05 to 1.0μ. Examples of aqueous resin emulsions having a glass transition point of 20°C or lower include (i) 2-ethylhexyl acrylate, n-butyl acrylate, ethyl acrylate, isopropyl acrylate, 2-ethylhexyl methacrylate, n-propyl acrylate; , n-butyl methacrylate, vinylidene chloride, ethylene, butadiene 20-100% by weight (ii) Vinyl acetate, ethyl methacrylate, vinyl chloride, n-propyl methacrylate, styrene, acrylonitrile, methacrylic acid Monomer selected from methyl, acrylic acid, itaconic acid, acrylamide, methacrylamide 80% by weight or less (iii) Monomer selected from diacetone acrylamide, maleic anhydride, diethylene glycol diacrylate 0 to 5% by weight Examples include emulsion polymers. In order to impart a sense of weight to the resulting nonwoven fabric, inorganic fillers and pigments such as calcium carbonate, iron oxide, ferrite, and barium sulfate can also be blended into this emulsion. The aqueous resin emulsion can be applied to the needled laminate 3 by sandwiching foamable resin particles between nonwoven fabrics by spraying, dipping, brushing, a foam coating machine,
This is done using a roll or the like. The amount of bucking material applied is 30 to 1000 g/m ² (solid content), preferably 80 g/m 2 (solid content).
~300g/ ^m2 . Generally, the total weight of the aqueous resin emulsion is 20 to 100% by weight (solid weight) of the weight of the nonwoven fabric. Generally, in order to completely impregnate the fiber mat with the emulsion, the applied emulsion is squeezed using squeeze rolls. The emulsion can be applied from one or both sides of the fiber mat. The fiber mat coated and impregnated with the emulsion is heated to 60-250°C to remove moisture, and the laying material is manufactured. During this heating and drying process, some of the expandable thermoplastic resin particles exist in the fiber mat in the form of foam particles, and some of them fuse together to form a foam sheet, giving the laying material moldability. Provides rigidity and shielding properties. Heat drying of the applied emulsion and foaming of the expandable resin particles can be carried out by any method. For example, heating cylinders, infrared heating machines,
Although a hot air dryer, a suction dryer, etc. can be used, it is preferable to use a hot air dryer. Moreover, drying can be performed at 80 to 180°C. In order to prevent fiber deterioration and to sufficiently perform foaming, it is preferable to use hot air at 100 to 140°C. By this heating, the foamable resin particles are expanded approximately 5 to 50 times, and the foam particles with a particle size of 0.5 to 4.5 mm or each other are fused to form a foam sheet, and the resin emulsion is installed in a fiber mat with backing. Ru. Further, when a fiber mat containing a fiber binder is used as the nonwoven fabrics 1 and 4, the fiber binder is melted when the emulsion is heated and dried, and the intertwining of the fibers in the fiber mat becomes stronger. (Effects) The laying material of the present invention has significantly improved rigidity and shielding properties due to the presence of the foam. Further, by heating the laying material to a temperature at which the foam melts and press-molding the laying material, the laying material can be shaped into a desired shape. Hereinafter, the present invention will be explained in more detail with reference to Examples. Manufacturing example of needle punch carpet 1 Nonwoven fabric for upper layer Plain type needle punch carpet made of polyester fiber and polypropylene fiber (80% polyester fiber, basis weight 350 g/m ² , density
0.117g/cm ³ ) was used. Example 2 Non-woven fabric for lower layer: Fiber mat made by randomly stacking 15 denier polyester fibers and polypropylene fibers (melting point 164°C) with a fiber length of approximately 100 mm (area weight 500 g/m ² ,
Needle-punched carpet (density 0.962 g/cm ³ ) with 15-18-32-3RB needles at a rate of 50 per square inch (80% polyester fiber ) was obtained. These needle-punch carpets were used as raw rug nonwoven fabrics in the following Examples and Comparative Examples. Example 1 Mitsui Petrochemical Industries Co., Ltd.
Co., Ltd.'s polypropylene fiber binder nonwoven fabric "Syntex PK-110" (product name, basis weight 50g/ ^m2 ,
(denier: 0.13 g/cm ³ , fiber diameter: 3 denier), and on top of this, expandable polystyrene particles (containing 5.5% by weight of butane) with an average particle size of 0.33 mm are arranged at a ratio of 170 g/m ² , and on top of that The needle-punched carpets for the upper layer were superimposed to form a laminate, and then needling was performed from the side of the nonwoven fabric for the upper layer to intertwine the nonwoven fabric fibers of the upper and lower layers. Next, an acrylic water-based emulsion "Acronal YJ-1650D" manufactured by Mitsubishi Yuka Verdice Co., Ltd. (trade name, resin solid content 50%, particle size 0.2 microns, film forming temperature) was applied to the entire surface of this laminate as a packing material. 7℃) in an amount of 250g/m ² (solid content),
The emulsion was then impregnated into the needle punch carpet using Niprol. Then, the emulsion-impregnated needle punch carpet was heated with hot air at 130°C for 15 minutes to remove moisture and foam the expandable polystyrene particles.
A paving material was produced comprising a layer of polystyrene foam particles having a bulk density of approximately 0.18 g/cm ³ and a particle size of less than 1.5 mm. Furthermore, this laying material was heated to 140℃ to soften the resin film and polystyrene foam of the backing layer, and then molded using a cooling press mold by applying a pressure of 20 kg/cm ² for 1 minute to form the interior floor of an automobile. manufactured carpets for Comparative Example 1 A material was laid in the same manner as in Example 1, except that the expandable polystyrene particles were not sandwiched between the upper and lower nonwoven fabric layers (the finished thickness was 6 mm).
The obtained product was further molded to obtain a carpet for an automobile interior floor. Example 2 Acronal as a resin aqueous emulsion
Instead of YJ-1650D, Mitsubishi Yuka Verdate Seat
Co., Ltd. acrylic ester/styrene copolymer emulsion “Acronal YJ-7082D” (product name, resin Tg approx. 120℃, solid content 50%, resin particle size approx.
A laying material having the physical properties shown in Table 1 was obtained in the same manner except that a material (0.3 micron) was used. In addition, this laying material was heated to 140°C to soften the resin film and polystyrene foam of the packing layer, and then molded using a cooling press mold by applying a pressure of 10 kg/cm ² for 1 minute to form the interior floor of an automobile. manufactured carpets for Comparative Example 2 A laying material having the physical properties shown in Table 1 was obtained in the same manner as in Example 2, except that the expandable polystyrene particles were not used. In addition, the evaluation of the carpet is based on the following method. Three-point bending strength: A sample piece (length 150 mm, width 50 mm) is supported with a span of 100 mm, and a deformation load is applied perpendicularly to the sample piece at a rate of 50 mm/min at the center point of the sample using an Instron type testing machine. The maximum bending resistance value was measured when a load was applied. Impermeability: Conforms to JIS A-6910 water permeability test. The water head is set to 250mm, and the judgment is made after 12 hours. ×: Water did not penetrate through the back surface and remain. △: Water bleeding is observed on the back side. ○: No water bleed is observed on the back side. 【table】

[Brief explanation of drawings]

FIG. 1 is a sectional view of a laminate used for carrying out the present invention. In the figure, 1 is a nonwoven fabric for the lower layer, 2 is a fiber binder nonwoven fabric, 3 is expandable polystyrene particles, 4 is a nonwoven fabric for the lower layer, and 5 is a laminate.

Claims (1)

[Claims] 1. The surface of the nonwoven fabric for the lower layer has a melting point of 60 to 200°C,
A nonwoven fabric made of a thermoplastic resin fiber binder with a basis weight of 6 to 200 g/m ² is layered, foamable thermoplastic resin particles are layered on top of the nonwoven fabric, and a nonwoven fabric for the upper layer is layered on top of this to form the nonwoven fabric for the upper layer and the nonwoven fabric for the lower layer. A laminate with a structure in which expandable thermoplastic resin particles are sandwiched between nonwoven fabrics is formed, and this laminate is needle-punched to intertwine the upper and lower layers, and then an aqueous resin emulsion is applied to this needle-punched nonwoven fabric laminate. 1. A method for producing a laying material, which comprises coating and impregnating the material, then heating the coated surface to foam the expandable thermoplastic resin particles, and drying the aqueous resin emulsion. 2. A needle-punched nonwoven fabric in which the lower layer nonwoven fabric is composed of 15 to 50% by weight of a resin fiber binder with a melting point of 80 to 180°C and 85 to 50% by weight of resin fibers or natural fibers having a melting point of 40°C or more higher than the fiber binder. The manufacturing method according to claim 1, characterized in that: 3. The manufacturing method according to claim 1, wherein the expandable thermoplastic resin particles are expandable polystyrene particles having a particle size of 1.5 mm or less. 4. The manufacturing method according to claim 1, wherein the expandable thermoplastic resin particles are used in an amount of 10 to 200 parts by weight per 100 parts by weight of the nonwoven fabric. 5. The manufacturing method according to claim 1, wherein the aqueous emulsion resin is applied to the nonwoven fabric laminate at a solid content of 30 to 1000 g/m ² . 6 The basis weight of the nonwoven fabric for the upper layer is 100 to 1000 g/ ^m2 , and the basis weight of the nonwoven fabric for the nonlayer is 100 to 1000g/ ^m2.
The manufacturing method according to claim 1, characterized in that: