JPS6146590B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a multi-layered laying material having a well-balanced elasticity and rigidity.
The laying materials obtained by carrying out the present invention can be used as interior materials for automobile ceiling materials, door trims, rear shells, floor mats, instrument panels, luggage mats, seat bags, consoles, etc., and molded materials for package trays, hats, and wall materials. It is useful as

Needle punch carpets are less heavy, luxurious, and cushiony than tufted carpets, Wilton carpets, and bratsel carpets, but they are cheaper and some have moldability. Used as an interior material for automobiles. The following are known as needle punch carpets having moldability.

(i) Needle carpet obtained by impregnating a needled web with rubber lux and drying (ii) Fibers such as polyethylene terephthalate and wool, polyethylene (melting point 118°C), linear polyester (melting point 140°C), polypropylene (melting point 135
A fiber mat made of a low melting point fiber binder such as (~164℃) is needled to temporarily bind the fibers in the upper and lower layers of the web, and then heated to melt the fiber binder and bond other fibers. Punch carpet (iii) Needled web has a softening point of 100-140
Needle punch carpet obtained by impregnating aqueous emulsion of thermoplastic resin at ℃ and drying (iv) Needle punch carpet obtained by impregnating the needled web with rubber latex containing low density polyethylene powder and drying. Among these needle punch carpets (i) to (iv), (iii) and (iv) are preferable in terms of moldability, particularly (iii), and (i) and (ii) are preferable. Things have less type fidelity. On the other hand, from the viewpoint of cushioning properties, needle punch carpet (ii) is preferable.

Therefore, the reality is that a needle punch carpet that has both moldability (diameter fidelity) and cushioning properties has not yet been obtained.

In order to obtain a needle-punch carpet having both performances, the present inventor used a fiber binder as the fiber web and a web made of fibers having a melting point 40°C or more higher than the melting point of the fiber binder.
The fiber mat obtained by needling this has 20 to 65 parts that are not impregnated with the aqueous emulsion of thermoplastic resin.
After drying, it was heated and press-formed at a temperature higher than the melting point of the fiber binder and lower than the melting point or thermal deterioration temperature (350 to 400°C) of other fibers. It has been discovered that a carpet having both moldability and rigidity can be obtained (see Japanese Patent Application No. 186642/1986).

However, in this method, it is difficult with the current coating method to impregnate the resin emulsion uniformly, in other words, to a determined depth of the fiber mat with high precision, and the resulting needle punch carpet has poor fabric weight, rigidity, and cushioning. It was confirmed that there were differences in gender.

In view of the drawback of the impregnation method that leaves an unimpregnated layer of resin emulsion, the present inventor has discovered that by overlapping an emulsion-impregnated fiber mat and a fiber mat containing a fiber binder and bonding them together, the variation in basis weight can be reduced. This heading led to the present invention. That is, the present invention comprises 15 to 50% by weight of a thermoplastic resin fiber binder with a melting point of 100 to 200°C, 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 fiber binder. Carpet A made of needled fiber pine
and Needle Punch Carpet B, which is made by impregnating the entire surface of the carpet with an aqueous emulsion of a synthetic resin with a melting point of 80 to 180°C and drying the semi-dried mackerel.
This invention provides a method for manufacturing a multi-layered laying material, which comprises melting or softening the fiber binder of the layers and the synthetic resin of the emulsion of the needle punch carpet B, and then applying pressure to bond the carpets together. be.

In carrying out the present invention, the needle carpet A constituting one layer of the laying material has a melting point of 100 to 200.
A fiber mat consisting of 15 to 50% by weight of a thermoplastic resin fiber binder of 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 was needled. This product is manufactured by a known nonwoven fabric manufacturing method. i.e. 1.2-300 denier, fiber length 25
~150mm thermoplastic fiber binder 15~50
Weight%, 1.2~300 denier, fiber length 25~150mm
85-50% by weight of synthetic and/or natural fibers
The mixed fibers are thoroughly mixed and opened, and then fed to a web forming device, and the resulting web (fiber mat) is stacked so that the card formed from the mixed fibers has the desired fiber weight. The fibers are temporarily fixed by needling and intertwining the fibers.

The fiber binder is used in a proportion of 15 to 50% by weight, preferably 20 to 40% by weight of the fiber mat weight. If it is less than 15% by weight, the contribution to improving the rigidity and dimensional stability of the obtained nonwoven fabric will be small. On the other hand, if it exceeds 50% by weight, it becomes like microwave felt, hard and brittle with impaired fiber texture.

In addition, the raw material for the synthetic fiber, which is the other fiber that substantially constitutes the fiber mat, has a melting point that is 40°C or more, preferably 70°C or more higher than the melting point of the thermoplastic resin fiber binder such as polyethylene terephthalate or polyamide. A thermoplastic resin having a Further, as natural fibers, cotton, linen, wool, etc. are used.

Needle punch carpet, which constitutes the other layer of the underlay material, is made of thermoplastic resin with a softening point (glass transition point) of 80 to 180°C after needling the fiber mat made of the above synthetic fibers and/or natural fibers. After applying or impregnating the aqueous emulsion so that the resin solid content of the emulsion is 15 to 300% by weight based on the fiber weight of the fiber mat,
It is heated and dried at 250℃ to remove moisture.

The thermoplastic resin of the emulsion impregnated into the fiber mat has a moldable temperature range of 800 DEG C. or higher, preferably 100 DEG to 180 DEG C., and a particle size of 0.01 to 5 microns. Specifically, styrene/acrylic acid lower ester copolymers (ester has 2 to 6 carbon atoms), methacrylate/acrylic acid lower ester copolymers, vinylidene chloride copolymers (vinylidene chloride content is 85% by weight or more) ), thermoplastic resins such as styrene-diene copolymers.

Optimally, (a) polyn-propyl methacrylate (Tg 81
°C), polystyrene (100 °C), polyacrylonitrile (100 °C), polymethyl methacrylate (105
℃), polymethacrylic acid (130℃), polyitaconic acid (130℃), polyacrylamide (153℃), etc., as well as (b) vinyl monomers, which are the raw materials for these polymers. 50
-100% by weight, preferably 65-95% by weight, and other vinyl monomers such as 2-ethylhexyl acrylate (Tg -85°C), n-butyl acrylate (-54
℃), ethyl acrylate (-22℃), isopropyl acrylate (-5℃), 2-ethylhexyl methacrylate (-5℃), n-propyl acrylate (8℃), n-butyl methacrylate ( 20℃), vinyl acetate (30℃), t-butyl acrylate (45℃),
2-hydroxyethyl methacrylate (55°C), ethyl methacrylate (65°C), isobutyl methacrylate (67°C), vinyl chloride (79°C), etc. or vinylidene chloride (-18°C) 50% by weight or less, preferably 35 Aqueous emulsion of a copolymer with ~5% by weight [In this section (b), Tg shown in parentheses is the glass transition point of the homopolymer of these vinyl monomers or vinylidene chloride], ( c) Resin aqueous emulsion 50 with Tg +80~155℃
~97% by weight, preferably 55-95% by weight, and a resin aqueous emulsion with a Tg of -85°C to less than +80°C 50~
3% by weight, preferably 45 to 5% by weight, and the like.

Fillers such as calcium carbonate, iron oxide, ferrite, barium sulfate, etc. may be added to this emulsion to give the obtained nonwoven fabric a sense of weight, and fillers such as low-density polyethylene, polystyrene, ethylene, etc. may be added to give moldability.・It is also possible to blend a low resin powder such as vinyl acetate monomer.

Furthermore, the fibers constituting the fiber mat may be a mixture of 15 to 50% by weight of a low-melting point fiber binder and synthetic resin fibers or natural fibers having a melting point 40°C or more higher than the fiber binder (patent application (See No. 186642).

Examples of means for applying or impregnating the fiber mat with the emulsion include a liquid roll, a squeezing roll, a spray gun, and dipping. 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, producing a moldable nonwoven fabric. During this heating and drying process, some of the resin particles in the emulsion remain in the fiber mat in a particulate state, and some form a film, which strengthens the entanglement of the fibers and forms them into the fiber mat. Gives strength and rigidity.

Note that it is not necessary to dry the aqueous emulsion before the carpet impregnated with the emulsion and the carpet containing other fiber binders are introduced into the heating furnace. Drying solidification and heating melting can also be performed simultaneously.

Stacking of needle-punched carpets is usually done by guiding both carpets into a heating furnace by means of guide rolls, and by using pressure rolls in one carpet after the fiber binder has been melted, and in the other carpet after the emulsion resin particles have been melted. This is done by fusing both mats together. The heating is carried out at a temperature that melts the emulsion resin and the thermoplastic resin fibers of the fiber binder, but does not melt the synthetic fibers and natural fibers that have a melting point of 40°C or more higher than the melting point of the thermoplastic resin fiber binder, for example, 130 to 250°C.
℃, preferably 190-230℃. The melting of the fiber binder entangles the synthetic fibers and/or natural fibers into a three-dimensional structure, imparting shape retention, and the use of the fiber binder to bond the molten emulsion resin between different types of carpet becomes strong. .

The simplest laminated structure is a two-layer structure in which a needle punch carpet 1 containing a fiber binder and a needle punch carpet 2 impregnated with emulsion and dried are bonded together as shown in FIG. As shown in Figure 2, it may have a three-layer structure in which one carpet layer is provided on both sides of a carpet 2 impregnated with emulsion and dried, or
Each of these carpets 1 and 2 may have four or more alternately repeated layers. Furthermore, as shown in FIG. 3, the needle punch carpet 1 containing a fiber binder is obtained by needling a surface layer mat 1a made of colored virgin fibers and a back layer mat 1b made of recycled fibers. Good too. Furthermore, the needle punch carpets 1a, 1b and 2 may be bonded together by heating and pressing.

The multi-layered laying material that has been given moldability in this way is heated to a temperature higher than the melting point of the emulsion resin and the resin that made up the fiber binder, and then compression molded into the desired shape. A molded product with both cushioning properties and rigidity can be obtained. At this time, by layering decorative paper, polypropylene sheet, ABS leather sheet, polyvinyl chloride leather sheet, and nonwoven fabric and compression molding, it is possible to obtain a molded product whose surface is decorated with these sheets. If a reinforcing material such as a plywood board, resin felt, or cardboard is used in place of these sheets, a composite molded article in which the nonwoven fabric and these reinforcing materials are integrated can also be obtained.

In practicing the present invention, the thickness of each layer varies depending on the application. For trunk mats, luggage mats, and floor mats, needle carpet 1 containing a fiber binder has a wall thickness of 0.5 to 10 mm, emulsion-impregnated and dried needle punch carpet 2 has a wall thickness of 0.5 to 10 mm, and the overall wall thickness is 0.5 to 10 mm. is 1~
It is used so that it is 20mm. As ceiling materials, the former carpet has a thickness of 1 to 5 mm, the latter carpet has a thickness of 2 to 5 mm, and the total thickness is 3 to 10 mm.

According to the method of the present invention, it is possible to reduce variations in the basis weight of a laying material having a multilayer structure, and to obtain a laying material that has excellent rigidity, cushioning properties, and shape retention.

In addition to the above-mentioned use as an interior material for automobiles, this laying material can also be used as a flooring material in a house or as an anti-slip material pasted on the surface of a pallet deck board.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts and percentages in the examples are based on weight unless otherwise specified.

Example 1 Mixed fiber waste of 20% recycled polypropylene (melting point 164°C) fiber binder of 15 denier and approximately 100 mm fiber length and 80% recovered polyethylene terephthalate (melting point 264°C) fiber of 15 denier and fiber length 75 to 125 mm was stacked randomly. Fiber matte (320g/m ² )
was needled using 15-18-32-3RB needles at a rate of 50 needles per square inch, resulting in a wall thickness of approximately 3.2
Needle carpet 1 with an apparent density of 0.10 g/cm ³ was obtained.

On the other hand, a fiber mat (680 g/m ² ) obtained by needling a web randomly stacked with the recovered polyethylene terephthalate fiber waste was mixed with styrene (85%) - methyl acrylate (12%) - acrylic acid (3 %) Aqueous emulsion of terpolymer [resin average particle size 0.1μ, solids content 50%, resin softening point approximately 120℃] was applied to a resin content of 350g/ ^m2 , and then coated with Nipprol. The entire web was impregnated with the emulsion.

Next, the moisture of the emulsion was removed using a cylinder dryer (150℃), and the basis weight was 1030g/m ²
Needle punch carpet 2 was obtained.

The above carpets 1 and 2 are guided into a suction dryer (furnace temperature 200°C) in layers using guide rolls, and passed through the dryer for 5 minutes to remove the polypropylene fiber binder from carpet 1 and the carpet from 2. After melting the above terpolymer, using a cooling roll, apply a linear pressure of 0.2Kg/cm.
Both carpets 1 and 2 are bonded together, and then cooled to room temperature. The thickness of carpet 1 containing the fiber binder is approximately 2 mm, and the thickness of carpet 2 impregnated with emulsion and dried is approximately 3.5 mm. A two-layered laying material having a density of 0.29 g/cm ³ and a total wall thickness of approximately 5.5 mm was obtained.

This laying material has a basis weight of 1350g/ ^m2 ,
The apparent density was 0.25 g/cm ³ . In addition, the cushioning properties and rigidity are good, and when trying to peel off the gap between carpets 1 and 2, the fibers of carpet 1 peel off before the delamination occurs, and the bending strength measured by the following method is 320g/3cm. It was wide and warm. Measurement method [Bending strength] Fix one end of the sample piece (length 120 mm, width 30 mm) and use an Instron type testing machine at a point 100 mm in the vertical direction from the fixed point perpendicular to the sample piece at a rate of 50 cm/min. The bending resistance value was measured when a deformation load was applied.

[rigidity]

When a sample piece (length 250 mm, width 30 mm) is placed on two triangular supports 15 mm inside from both ends (span distance is 220 mm), the sinking distance of the center position of this sample piece is Those within the wall thickness were considered to have good rigidity, and those exceeding the wall thickness were considered to have poor rigidity.

[Cushion properties]

A sample piece (40 mm long and 40 mm wide) was placed on a table, and a pressure terminal of 10 mm long and 10 mm wide was placed in the center of the sample piece using an Instron type testing machine to apply a pressure of 0.1 Kg/cm ² . A product in which the pressure terminal returned upward when the pressure was released was considered to have cushioning properties.

Comparative example 1 20% recovered polypropylene (melting point 164°C) fiber with 15 denier and fiber length of 100 mm and 15 denier with fiber length
A fiber mat (1000 g/m ² ) made by stacking 75 to 125 mm of recycled polyethylene terephthalate (melting point 264°C) mixed fiber waste of 80% fiber is 50 pieces per square inch using 15-18-32-3RB needles. Needling was carried out at a ratio of

This needled web is heated with hot air at 200°C for 3 minutes to melt the polypropylene fibers, and while the polypropylene is still in a molten state, the web is compressed using a cooling roll to approximately 5.5
It was made into a web with a thickness of mm.

The physical properties of the needle punch carpet thus obtained are as follows.

Apparent density 0.18g/cm ^3Bending strength 0Kg/3cm width Tensile strength 84Kg/3cm width Rigidity Poor Cushionability Good comparative example 2 Fiber mat (100g) made of randomly stacked polyethylene terephthalate fibers of 15 denier and fiber length 75-125mm / ^m2 ) using a 15-18-32-3RB needle at a rate of 50 needles per square inch, and then 350g/m2 of the aqueous emulsion of the terpolymer used in Example 1 with a Ritzker roller. m ² (solid content), and then the entire fiber mat was impregnated with the emulsion using Niprol.

After heating this at 120℃ to remove moisture, it was heated for 60 seconds with a far infrared heater with a surface temperature of 180℃ to melt the terpolymer, and then compressed using a compression roll to obtain the following physical properties. I got a needle punch carpet.

Wall thickness: approx. 5.5mm Weight per unit area: 1350g/m ^2Apparent density: 0.25g/cm ^3Bending strength: 260g/3cm width Rigidity: Yes (but inferior to that of Example 1) Cushionability: Poor

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are all cross-sectional views showing an example of a laying material having a multilayer structure obtained by implementing the present invention. In the figure, 1 indicates a needle punch carpet containing a fiber binder, and 2 indicates a needle punch carpet impregnated with emulsion and dried.

Claims (1)

[Claims] 1 Fiber consisting of 15-50% by weight of a thermoplastic resin fiber binder with a melting point of 100-200°C and 85-50% by weight of synthetic or natural fibers having a melting point 40°C or more higher than the melting point of the fiber binder. Carpet A made by needling pine and has a melting point of 80~
After impregnating the entire surface of the carpet with an aqueous emulsion of synthetic resin at 180°C and layering it with semi-dry or dried needle punch carpet B, this layered carpet is applied to the fiber binder of the A layer and the needle punch B of the layer B. A method for manufacturing a multi-layered laying material, characterized by melting or softening the synthetic resin of the punch carpet emulsion and then applying pressure to bond the carpets together.