JPS6030772B2 - Method for manufacturing multilayer bulky nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves adding a curing agent to an emulsion of an initial to intermediate reactant to form a thermosetting resin for a fibrous web of two or more layers formed using different fiber types and weaving degrees. The present invention relates to a method for producing a multilayer bulky nonwoven fabric by applying a binder containing a catalyst and the like and processing it by an impregnating method.

One of the conventional methods for manufacturing multilayer bulky nonwoven fabrics is to vary the types and grades of the constituent fibers and develop them into a web, which is then stacked in predetermined layers to form a multilayer web. Next, it is sandwiched between upper and lower steel plates and led to a bond soaking tank.
The material is impregnated with a binder liquid mainly consisting of a thermoplastic resin emulsion, excess liquid is removed using a squeezing roll, and the material is dried and heat treated.

However, in this case, the multilayer laminated fiber web completely loses its bulkiness during formation, and is finished with a thickness that is compressed by the squeezing roll. It is impossible to obtain a nonwoven fabric with a varying density gradient or a nonwoven fabric with a sandwich structure in which each layer has a different density. Therefore, in order to produce multi-layer bulky non-woven fabrics, the type of fibers and
A web with a relatively small amount of fibers with a different weave is formed, and a binder liquid is sprayed from the surface to bond and fix the fibers of the web while maintaining the bulkiness of the web as it was when it was formed. Roll it up once. Next, a method has been considered in which a plurality of these layers are stacked as appropriate, and then impregnated with a binder liquid mainly composed of synthetic rubber or thermoplastic resin emulsion to integrally bond each layer to form a multilayer bulky nonwoven fabric. . However, this manufacturing method is not continuous, the work is complicated, and the process of spraying the binder liquid causes the machine to become dirty and material loss is severe, wrinkles occur easily during lamination, and the surface smoothness is not good, resulting in a high rate of product failure. In addition, in order to maintain bulk, the webs that have been temporarily fixed by spraying the binder are impregnated with a binder liquid in order to stack and bond them together. In addition to the bonding agent that sticks to the surface where it was temporarily fixed in advance, the impregnated bonding agent that bonds between the layers causes more bonding agent to stick to the laminated surface than to the inside of each fiber layer. There are problems such as the formation of thin layers where the laminated layers are clearly separated by visual inspection, which affects the perforation performance. Therefore, there has been a strong desire for a continuous manufacturing method using a forgery method that allows continuous manufacturing in one step as a relatively simple manufacturing process. The present invention solves these problems, simplifies the manufacturing process, is inexpensive, is manufactured continuously in one step, has a bulky, multilayered structure, and is separated by aggregation of a binder between the laminated layers with different layer densities. The present invention provides a method for producing a bulky nonwoven fabric that does not form layers.

That is, the present inventor has constructed a multilayer bulky nonwoven fabric in which the single-layer fiber web constituting each layer uses one or more types of single or mixed fibers, and each has the same or different grades. A curing agent, catalyst, etc. are added to a bisphenol A glycidyl ether type epoxy resin emulsion as an initial or intermediate reactant emulsion to form a thermosetting resin in a multilayer web formed by laminating two or more layers of fiber webs. The fibers are impregnated and filled with a binder, dried, and heat treated to solidify the binder and bond the fibers together, resulting in bulky and porous properties.The fibers and grade of each layer can be arbitrarily changed. By forming a bulky nonwoven fabric that is integrally bonded, the bulky nonwoven fabric can be constructed by gradually varying the apparent density and voids, thereby making it possible to continuously produce a multilayer bulky nonwoven fabric using the infiltration method. The most important point to keep in mind when producing such a bulky multilayer nonwoven fabric is that, unlike the conventional nonwoven fabric that uses a single-layer uniformly mixed fiber web, the bulky multilayer structure does not have a high degree of weave or fiber type. Obtaining a uniform distribution of the binder to prevent the migration phenomenon of the binder during the drying process after impregnation of the binder to laminate multiple layers of different fiber webs, i.e., the mutual adhesion of the fibers between each web layer. Gender becomes an issue. Therefore, in order to obtain a multilayer bulky nonwoven fabric with uniform binder distribution and good interlayer adhesion without clearly distinguishing each layer, the difference in fiber weave between each layer should be within 1:5 times, preferably within 1:3. In addition, when the laminated web forms multiple layers, for example, it consists of two layers AB, the fibers used for layer B are mixed into the fiber web of layer A, and the fibers used for layer B are mixed into the fiber web of layer A.
It is preferable to use a fiber web in which the fibers of layer A are mixed in the fiber web of the layer.

Next, a nonwoven fabric is made using a binder mainly consisting of an emulsion of an initial or intermediate reactant that forms the thermosetting resin used in the present invention, and another using a binder mainly consisting of an ordinary thermoplastic resin emulsion. Comparing the difference in finished thickness when manufactured, if we assume that the apparent thickness when a certain weight of web is passed through a squeezing roll using simple water as the soaking liquid and dried is 1. When a certain amount of a binder mainly consisting of a thermoplastic resin emulsion is deposited, the thickness remains approximately 0.1 to 0.3, and the initial or intermediate reactant emulsion forming the thermosetting resin of the present invention is The thickness is 0 when a certain amount of the main binder is attached.
．． 45-0. This can be expressed as a comparative value of friendship.

That is, the thickness is 1.5 to 7 times the thickness when using a binder mainly composed of a thermoplastic resin emulsion. This is because the adhesive force is slow to develop when the binder is based on the initial or intermediate reactants that form the thermosetting resin, and after the thickness of the web is restored by drying and evaporation of water in the drying process, the epoxy resin is then heated. Such bulkiness is probably obtained because the bonding between the fibers occurs at the same time as the melt reaction hardening. In addition, when these binders are used, and the ratio of binder adhesion to the fibers is less than 5%, the bulkiness that has been developed is so unstable that it cannot be maintained with a slight pressure applied from the outside. If it exceeds 100%, the nonwoven fabric product will become extremely hard, resulting in an unfavorable texture and texture.At the same time, the large amount of binder will increase adhesive strength, resulting in insufficient thickness development, which is actually disadvantageous. It's coming.

Therefore, a solid content concentration of 5 to 50% is appropriate. The manufacturing method of the present invention will be explained in more detail below with reference to Examples. Example 1 As a lower layer web, polyester fibers of 3 denier and cut length 51 and fibers of 6 denier and cut length 51 were mixed at a mixing ratio of 80:20, and a fiber web with a fiber weight of 80 was prepared. As an intermediate layer web, a thin layer of polyester fibers of 3 denier, cut length 51 ribs and 6 denier, cut length 51 side fibers are mixed at a mixing ratio of 50:50, and the fiber weight is 100 layers/end. Furthermore, as an upper layer web, polyester fibers of 3 denier, cut length 51 ribs and fibers of 6 denier, cut length 51 side are mixed at a mixing ratio of 40:60, fiber weight 100.
Evening/Layering that fiber web.

The upper, middle, and lower web layers are sequentially laminated to form a laminated mat.The structure of these continuous webs is a fiber mat in which each layer has a different fiber composition by a commonly known lamination method. It can be used as a type of object. In Fig. 1, 1 shows a cross section of a mat-like material in which these three web layers are laminated, 2 is an upper layer web, 3 and 4 are intermediate and lower layer webs, respectively, and show how the fibers are piled up due to the difference in fiber composition. It represents something. In order to prevent the three-layer fiber mat from losing its shape, it was sandwiched between upper and lower wire meshes and impregnated with a binder liquid having the following composition, which is an emulsion of an early to intermediate reactant to form a thermosetting resin.

Digly Sisy Ether. Bisphenol A emulsion (trade name Epomik A-13 Mitsui Kanebo Epoxy K.
K) 10 anchors hardener-modified polyamide. Amine (trade name Epomik B-15 Mitsui Kanebo Epoxy K.K) 22 parts water Total solids concentration
Remove the 20% excess liquid with a squeezing roll and place it on a wire mesh conveyor.
It was dried for 0.7 minutes and then heat-treated at 140° C. for 6 minutes to obtain a nonwoven fabric having a cross section as shown in FIG.

Although the bulk is considerably reduced from the fiber mat made of laminated webs in Fig. 1, it still has sufficient porosity or voids, and the interlayer between the upper layer 6 and the middle layer 7 is the same as when the web is laminated. The thickness of the lower layer 8 is considerably reduced compared to that of the web, and the difference between the upper and middle layers is clearly visible. The dry resin adhesion amount of this product was 20%, and the product weight was 336 cm/18 cm in total thickness. Assuming that the amount of bonding agent attached is the same in all layers, the thickness of the upper and middle layers is approximately 16 ribs, so the apparent density of this layer is 0.
．． 0.015/cc, whereas the thickness of the lower layer is about 2 skins, so its density is approximately 0.048/cc. It is a bulky multi-purpose L nonwoven fabric with two layers of different densities. be. When this product was used as an air filter, the initial ventilation resistance was 12 Aq/2 skin/sec, and the average dust collection efficiency was 56% when measured by the discoloration method at a wind speed of 2 W/sec.

For comparison, Figure 3 shows the same fiber laminated mat as described in the above example, impregnated with a binder liquid of the following composition mainly consisting of a thermoplastic resin emulsion, butajesose styrene copolymer emulsion, and heat-treated in the same manner. It is something that Butadiene-styrene copolymer emulsion (trade name Crossrene SA-2 Gogata Pharmaceutical K.K.) 10 eaves Water-soluble melamine resin (trade name Sumitex M-3 Sumitomo Chemical K.K.) 1$ Miyako Catalyst ( Product Name: Sumitex Accelerator ACX
36 m/cc, thickness of 5 fences, density of 0.06 W/cc, cross section as shown in Figure 3, the difference in density between the upper middle layer and the lower layer is not noticeable, forming a flat and delicate layer, and the initial ventilation Resistance is uneven skin Aq/
2 skins/sec, making it unsuitable for use as an air filter. Example 2 As the lower layer web, 80% of polyester fibers of 3 denier and 51 length and 20% of 6 denier and 51 length were thoroughly mixed through a mixer, and then processed into a carding machine with a fiber amount of 80 mm/mm. A web is formed, and the upper layer web is made of polyester fibers of 3 denier, 50% of which have a cut length of 51 ribs, 50% of which has a cut length of 6 denier and 51 ribs, and a fiber amount of 100 mm.The web is laminated on the lower layer web. It was then impregnated with a binder liquid having the following composition.

Digly Sisy Ether. Bisphenol A emulsion (trade name Epomik A-3 Mitsui Kanebo Epoxy K.
K) Part 10 hardener-modified polyamide. Amine (trade name Epomik B-15 Mitsui Kanebo Epoxy K.K) 22 parts water Total solids concentration
Remove the excess liquid with a squeezing roll and place it on a wire mesh conveyor.
It was dried for 0q07 minutes and then heat treated at 140°C for 6 minutes.

Dry resin adhesion amount (D.P.U) 30%, product weight 234
Evening/end, the thickness of the middle upper layer of 14 ribs is about 12 and the density is 0.011ta'cc, the thickness of the lower layer is about 2 skin and the density is 0.
．． 052 evening/cc and bulky with different densities,
A nonwoven fabric without a segmented layer due to the aggregation of the binder between the laminated eyebrows was obtained. Ventilation resistance 11. A filter suitable for passing through dust and dust furnaces for buildings and factories was obtained at a speed of 2 m/sec. The product with this structure, which was treated in the same way as above with a thermoplastic resin compound, had a product weight of 234 mm/cm and a thickness of 7 mm.
The kite wasn't bulky. Example 3 As the lower layer web, 50% of polyester fibers of 6 denier, 51 length and 50% of 3 denier 51 length were thoroughly mixed through a mixing machine, and then a web with a fiber content of 100 t' was made using a carding machine. The intermediate layer web is made of 20 denier nylon fibers, cut long ribs, and the fiber amount is 100 mm.The upper layer web is made of the same fiber as the lower layer web and is laminated with the 100 mm web. .

These three layers of laminated mats, top, middle, and bottom, were impregnated with the same binder solution as in Example 2 and heat-treated. Figure 4 shows a cross section of the nonwoven fabric thus obtained, showing that the upper layer 9 and the lower layer 11 have layers that are denser than the intermediate layer 10, and are sandwich-like with no dividing layer due to the concentration of binder between the laminated layers. It became a structure. The weight of the product is 390mm/cc, and the thickness of the upper and lower layers is approximately 3 ribs each on the 16th side, so the approximate apparent density is 0.043mm/cc for the upper and lower layers, and the thickness of the middle layer. Since IQ was boiled, it was 0.013 m/cc.
As described above, the present invention has two layers composed of a binder made by adding and blending a curing agent and a catalyst to an emulsion of initial or intermediate reactants forming a thermosetting resin, and fibers having different types, weaves, and composition ratios. By using the above multilayer web and using binder impregnation and filling methods such as bond filling, horizontal roll, and spray filling, a binder mainly consisting of a thermoplastic polymer emulsion is used. A bulky multi-layer non-woven fabric that cannot be obtained by the non-woven fabric manufacturing method using a binder using the bonding method is formed, and by arbitrarily changing the type of fibers and the degree of weaving between each layer of the multi-layer, the apparent density or voids in each layer can be reduced. Unlike bulky non-woven fabrics made by conventional spray methods or non-woven fabrics soaked and bonded using conventional water-soluble or solvent-based thermosetting resins, adhesive strength between each layer and between fibers is strong. A nonwoven fabric with an integrated bulky multilayer structure that is uniformly and firmly bonded to the inner layer of the web is obtained, and bulkiness is previously imparted by spraying as in the conventional bulky nonwoven fabric manufacturing method, and then several sheets are laminated and bonded by immersion bonding. It is characterized by the fact that non-vertical fabrics with a bulky multi-layered structure and different apparent densities between layers can be easily and continuously manufactured in one process without the need for complicated processes. It has excellent chemical resistance, water resistance, and oil resistance, and has significantly improved resistance to applied pressure.It has a multilayer structure, so it has excellent dust collection efficiency as a gas or liquid furnace cloth, and has a large internal furnace overvolume. It exhibits the effect of being durable for long-term use, and furthermore, when the method of the present invention is used, the economic effect due to the reduction in the manufacturing process is extremely large.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of a laminated mat made by laminating webs with different weave degrees of fibers to obtain the product of the present invention, and FIG.
FIG. 4 is a cross-sectional view of a nonwoven fabric product obtained by treatment with a binder liquid. 1...Fiber laminated mat (unbonded state), 2...
... Upper layer web (unbonded state), 3... Middle layer web (unbonded state), 4... Lower layer web (unbonded state), 5... Bulky porous nonwoven fabric with two-layer structure, 6...
... Upper layer part, 7... Middle layer part, 8...
...Lower part, 9...Upper part, 10...
...Middle layer part, 11...Lower layer part. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Bisphenol A glycidyl ether type epoxy is added as an emulsion of an initial or intermediate reactant to form a thermosetting resin to a multilayer web formed by laminating two or more layers of fiber webs formed by combining fiber types, finenesses, and blending ratios. A resin emulsion is impregnated with a binder containing an amine curing agent and a catalyst, passed through a squeezing roll so that the solid content of the binder is 5 to 100% of the total fiber weight, and then dried. , heat treatment is applied to dry and evaporate water, and as the epoxy resin melts, the thickness of the fiber layer is restored to approximately its original thickness, and at the same time, the fibers constituting the web and each fiber layer are unified by reaction hardening of the molten resin. A method for producing a multilayer bulky nonwoven fabric, which comprises bonding and fixing the fabric, and forming a density gradient in which the densities of the fiber layers of the bonded integrated fiber layers are different so that no segmented layer is created between the layers due to the aggregation of the binder.