JPS6253635B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fiber mat that can be bonded simultaneously with thermoforming during thermoforming.

It is well known that in the past, felts made of fiber materials, knitted raised products, etc. have been widely used for musical instrument case linings, automobile interior materials, etc. When attaching to the
Emulsion adhesives were used.

However, in recent years, due to advances in synthetic chemistry, hot-melt heat-sensitive adhesives have attracted attention, and applications in various fields have been developed, and they have come to be widely used for adhesive applications such as those mentioned above.

On the other hand, three-dimensional molded sheets and mats are made by impregnating or coating a flat sheet or mat material with a thermoplastic adhesive and then heat-forming it. For adhesion, after impregnating or coating with moldable resin, film-like,
The only method available was to use a reticulated hot melt adhesive to bond the product to the main body during heat molding.

This method has problems such as misalignment between the surface material and the adhesive sheet during thermoforming, and has the disadvantage of poor workability. Improvements were made to try to unify them.

However, no matter how much improvement is made, two steps are still inevitable: applying a moldable resin and attaching a heat-sensitive sheet to the back side to integrate, and no improvements have been achieved in the process. .

The present invention addresses the above-mentioned circumstances and aims to provide a fiber mat that can be heat-formed and bonded simultaneously in one step.

That is, in the present invention, when a three-dimensional structure is formed by heat molding, the surface fiber layer is not altered or deformed at all, but the intermediate binder layer reaches its softening point and deforms, making it easy to form a three-dimensional structure. At the same time, the adhesive layer on the back side reaches the melting point of the hot melt powder placed there, and features a new structure of fiber mat that can be easily adhered to pre-prepared undercussion material during heat molding. shall be.

Hereinafter, details of the fiber mat of the present invention will be explained with further reference to the accompanying drawings.

FIG. 1 schematically shows the cross-sectional structure of the fiber mat of the present invention, which includes a surface layer 1 consisting of a napped fiber layer, and a layer continuous to the surface layer 1 below the surface layer 1. a binder layer 2 made of a thermoplastic emulsion resin; a lower part of the binder layer 2;
That is, it consists of three layers, including an adhesive layer 3 made of a powdery heat-sensitive adhesive layered on the back side.

In the above three-layer structure, the fibers that make up the surface layer, the thermoplastic emulsion resin that makes up the binder layer, and the powdery heat-sensitive adhesive that makes up the adhesive layer are all polymeric materials, which will be described later. As such, they have different melting points and softening points.

Among these, the fibers that constitute the surface fiber layer 1 and substantially determine the layered structure of the fiber mat are spun by dissolving natural polymers such as viscose rayon, polyamide, polyester, acrylic, polypropylene, and vinylon, or synthetic fibers. Fibers obtained by spinning high molecular weight polymers are used and have a softening point of at least 140.
℃ or higher is a desirable condition in relation to the intermediate layer and adhesive layer during thermoforming.

Further, in order to form the intermediate layer 2, moldable thermoplastic resins mixed and impregnated into a layer approximately half the thickness of the mat formed in the layered body include vinyl chloride resin, vinyl acetate resin, polyethylene resin,
Examples include vinylidene chloride resin, high styrene SBR, and acrylic acid ester resin, and these are used alone or in the form of a copolymer thereof. These resins are polymers with a thermoplastic temperature, that is, a softening point of 100 to 130°C, and are liquid resin binders.

On the other hand, the type of heat-sensitive adhesive for the back adhesive layer 3 is as follows:
Polyethylene, EVA, modified nylon, modified ester, PVC, etc., all of which have a melting temperature of 120°C.
The following solid granular or powder adhesives are used, and the particle size is preferably about 50μ to 300μ.

Next, the fiber mat of the present invention having each composition structure as described above, unlike conventional fiber mats that can be molded and bonded, can be manufactured in one step. It can be obtained by layering a fiber mat using known means, and then coating the mat with an appropriately selected thermoplastic emulsion resin mixed with the hot melt adhesive powder from the back side. can. At this time, the thermoplastic emulsion resin enters through the interfiber spaces of the fiber mat and impregnates the fiber mat to about 1/2 in the thickness direction to form the intermediate layer 2, and the hot melt adhesive has a filter effect on the fiber mat. It stays on the back side and adheres to the fiber mat to form the adhesive layer 3. The amount of thermoplastic applied is in the range of 150 to 500 g/m ² such that the amount of adhesive remaining on the back side is in the range of 30 to 100 g/m ² , that is, 4:1 to 5:
Preferably, it is applied at a ratio of 1:1.

The resulting pine is then subjected to drying. Particularly in the above case, the conditions for the polymeric material forming each layer are important; When mixing powder or granular adhesive into the resin, it is preferable to use an adhesive whose melting or softening temperature is 20°C or more lower than that of the resin in order to make the subsequent heat molding more effective. , each component, ie, fiber, resin, and adhesive, is selected within that range, and the viscosity of the resin and adhesive is adjusted to coat the fiber mat from one side.

The fiber mat thus obtained has a layered structure as shown in FIG. The undercussion material is put into a mold prepared in advance and cooled under pressure to form a three-dimensional shape. Adheres to hard paper, etc.

FIG. 2 shows an embodiment in which the fiber mat of the present invention is heated, pressurized, and cooled in the above-mentioned mold.
2 and 3 are a fiber layer, a binder layer, and an adhesive layer, respectively, as in FIG. 1, 4 and 5 are upper and lower molds of a molding die, and 6 is an undercussion material. In the figure, the powdery heat-sensitive adhesive is melted and adhered to the undercussion material 6.

7 indicates the adhesive portion.

Although the present invention has been described above using three types of polymer materials, it is of course possible to use even more types of polymer materials within the scope of the present invention. Yes, various deformed structures are allowed.

More specific examples of the fiber mat of the present invention are listed below.

(Example 1) A fiber fleece with a web weight of 500 g/m ² was made with a ratio of 60% blue-colored polyester fibers of 30 d x 76 mm and 40% of dark blue-colored polyester fibers of 15 d x 64 mm. wire count
First, I made ^a flat needle felt by needling 150 needles/inch from the top and bottom using a No. 32 needle. After that, use a hook needle to pitch 5 from the back side.
A patterned patch with a depth of 15 mm was used to create a needle felt with a brushed appearance. A copolymer of ethylene vinyl acetate and acrylic is used as a thermoplastic emulsion resin that can be molded at 120°C on this felt-like fiber mat, and powder of ethylene vinyl acetate copolymer (EVA) with a melting point of 90°C is added to this felt-like fiber mat. The blended resin was mixed as a heat-sensitive adhesive and the viscosity was adjusted, and this blended resin was applied to the back side of the fiber mat, and the fiber mat was press-fitted with a pressure roll so that the thermoplastic resin was impregnated to the center of the fiber mat.

The amount of thermoplastic resin applied at this time was 200g/ ^m2 , and the amount of heat-sensitive adhesive powder remaining on the back side was 50g/ ^m2.
It was hot.

Next, it was thoroughly dried in a hot air dryer to produce a mat that can be bonded simultaneously with heat molding. After cutting this pine into specified dimensions, it is placed in a heating furnace with a heating temperature of 150℃ and left for 10 minutes.The pine is taken out with its middle layer softened and the back side molten.The undercussion material is prepared in advance. When the mat was put into a mold of a molding machine and cooled under pressure, it was able to sufficiently adhere to the under felt and obtain a molded mat with a three-dimensional structure.

The adhesive strength at this time was 250 g/5 cm width.

(Example 2) A fiber fleece with a web weight of 650 g/m ² was made by mixing 30% polypropylene 15d brown and 70% polyester 6d beige as fiber materials, and it was woven from the top and bottom using a wire size 32 needle. After making a flat needle felt by needle punching with 150 needles per 2.54 cm square, punch it with a hook needle to a depth of 7 with a pitch of 2 mm.
A loop-like fiber mat was created by pattern punching under mm conditions. Next, a moldable thermoplastic resin made of vinyl chloride and EVA copolymer, which exhibits plasticity at 100°C, was mixed with EVA powder that melts at 80°C, coated with a roll coater, and pressed into the center of the fiber mat.

The amount of thermoplastic resin at this time was 300 g/m ² and the amount of powder was 70 g/m ² . This pine was dried, cut, and molded under the following conditions.

Heating temperature: 140℃ Time: 10 minutes Pressure: 0.6Kg/cm ² Pressure time: 20 minutes (molding cooling time) As a result, we were able to obtain a product that was bonded at the same time as molding, and the strength of the bond with the hardboard at that time was
It was 400g/5cm wide.

As described above, the fiber mat of the present invention does not require the two steps of applying a moldable resin like conventional fiber mats and the step of applying a heat-sensitive adhesive to the back side and integrating the resin. It can be easily manufactured in one step, and during thermoforming, the surface fiber layer does not undergo any deformation due to the difference in melting point and softening point of the polymeric materials forming each layer, and the intermediate binder Three-dimensional molding is easy due to the layers, making it extremely useful for producing various molded products. Simultaneous adhesion is possible by melting a low-melting adhesive, making it suitable for a wide range of applications such as automobile interior materials and case linings. This is Matsuto.

[Brief explanation of the drawing]

Figure 1 is a schematic sectional view of the fiber mat of the present invention, Figure 2 is a schematic cross-sectional view of the fiber mat of the present invention;
The figure is a sectional view showing the form of molding during heat molding. 1... Surface fiber layer, 2... Intermediate layer, 3... Back adhesive layer.

Claims (1)

[Claims] 1 Consisting of a raised surface layer made of a first polymeric material fiber layer, and a second polymeric material formed on the lower surface of the surface layer by impregnating approximately the lower half of the thickness of the raised surface layer. It consists of a moldable thermoplastic emulsion resin intermediate layer and a hot-melt powder adhesive layer made of a third polymeric material attached to the lower surface of the resin intermediate layer, each of which has a melting point. The melting point of the second polymeric material is lower than that of the first fiber-forming polymeric material, and the melting point of the third polymeric material is different from that of the first fiber-forming polymeric material.
A fiber mat capable of simultaneous heat molding and bonding, characterized in that its softening point is lower than that of the second polymer material.