JP2019116076A - Multilayer mat and method of manufacturing multilayer mat - Google Patents

Abstract

To provide a multilayer mat hard to generate lag and exfoliation at an interlayer even if bending a mat, and tucking the mat into a gap having a definite distance, and capable of sufficiently exerting a function as a mat in the case of supporting an exhaust gas treatment body.SOLUTION: The multilayer mat 10 is obtained by laminating a plurality of mats composed of an inorganic fiber where an adhesive layer 13 for bonding the mats each other is formed between the mats, a plurality of holes 11b, 12b are formed on principal faces 11a, 12a by which respective mats face each other, and the inside of the holes 11b, 12b is filled with an adhesive composing the adhesive layer 13.SELECTED DRAWING: Figure 1

Description

The present invention relates to multilayer mats and methods of making multilayer mats.

The exhaust gas emitted from an internal combustion engine such as a diesel engine includes particulate matter (hereinafter also referred to as PM) such as soot. In recent years, it has been a problem that this PM harms the environment and human bodies. It has become. Further, since the exhaust gas also contains harmful gas components such as CO, HC, and NOx, there is also concern about the influence of the harmful gas components on the environment and the human body.

Therefore, as an exhaust gas purification apparatus for collecting PM in exhaust gas or purifying harmful gas components, a casing for containing an exhaust gas treating body made of porous ceramic such as silicon carbide or cordierite, and an exhaust gas treating body Various types of exhaust gas purification apparatuses have been proposed, each of which is composed of a holding sealing material made of an inorganic fiber assembly disposed between an exhaust gas treating body and a casing.

The holding sealing material prevents the exhaust gas treating body from being damaged by contact with the casing covering the outer periphery thereof due to vibration or impact caused by traveling of the automobile or the like, or the exhaust gas is discharged from between the exhaust gas treating body and the casing. It is disposed mainly for the purpose of preventing leakage and the like. Therefore, the holding sealing material is required to have a function of reliably holding the exhaust gas treating body by increasing the surface pressure generated by the repulsive force caused by the compression.

As such a holding sealing material and heat insulation, damping / vibration control, and a sound absorbing material, a holding sealing material consisting of a plurality of laminated mats in which materials of two or more layers are combined may be required. As a layer to be laminated, a combination of an intumescent mat and a non-intumescent mat, a combination of a plurality of mats having different intumescent properties, etc. may be mentioned.
Further, even when the mat is used as a soundproofing material or the like, it may be considered to combine two types of mats having different materials and characteristics in order to enhance the soundproofing performance.

Patent Document 1 includes a first layer, a second layer, and an adhesive interposed therebetween to bond the main surface of the first layer and the main surface of the second layer together. Disclosed is a multilayer mounting mat wherein the adhesive comprises at least one of inorganic colloidal particles having an average diameter of less than about 300 nm and an inorganic water soluble salt.

According to paragraph [0130] of the specification of Patent Document 1, “The adhesive is usually in the form of a liquid. However, some mat layers (eg, needle tacked or dry mounted without an organic binder) For the matte layer), it may be preferred that the adhesive is in the form of a gel, for example (1) removing water, (2) altering the pH, (3) adding a salt, or (4) It can be formed by adding a water-miscible organic solvent, the degree of gelation can be controlled by optimizing the viscosity, thereby reducing the absorption of the adhesive into the mat layer. " As described above, in Patent Document 1, an inorganic binder in the form of a gel which suppresses the absorption of the adhesive to the mat is used as an adhesive for bonding the mat.

JP 2009-539031 gazette

However, the multilayer mounting mat according to Patent Document 1 has the following problems.
That is, the gel adhesive hardly penetrates into the inside of the mat, and the mats are bonded only on the surface of the mat, so the multilayer mounting mat may be bent or pressed into a gap having a certain distance. At the time of carrying out, there is a problem that peeling or displacement is easily generated between layers, and the function as a mat used for a holding sealing material can not be sufficiently exhibited.

The present invention has been made in view of such problems, and it is difficult for displacement and peeling to occur between layers even when the mat is bent or the mat is pushed into a gap having a predetermined distance, and the exhaust gas treating body It is an object of the present invention to provide a multilayer mat and a method of manufacturing the multilayer mat, which can sufficiently exhibit the function required of the mat in the retention, the soundproofing material, and the like of the present invention.

The multilayer mat of the present invention is a multilayer mat in which a plurality of mats made of inorganic fibers are laminated,
Between the mats, an adhesive layer is formed to bond the mats together,
A plurality of holes are formed on the main surfaces of the mats facing each other,
The adhesive constituting the adhesive layer is characterized in filling the inside of the hole.

In the multilayer mat of the present invention, a plurality of holes are formed on the main surfaces of the mats facing each other, and the adhesive constituting the adhesive layer fills the inside of the holes. Even when the adhesive layer in the inside exerts an anchor effect and the multilayer mat is bent or a multilayer mat is pressed into a gap with a certain distance, for example, between the exhaust pipe and insulator cover, etc. It is hard to generate | occur | produce and can fully exhibit the function as a mat | matte in holding | maintenance etc. of an exhaust-gas-treatment body.
Further, in the multilayer mat of the present invention, since the adhesive layer is present between the mats, the heat transfer and the transmission of sound are interrupted, and the multilayer mat is excellent in heat insulation, soundproofness, vibration control and vibration resistance.

In the multilayer mat of the present invention, it is desirable that the plurality of holes formed in the mats facing each other be formed in a mutually offset state.
In the multilayer mat of the present invention, when the plurality of holes formed in the mats facing each other are formed in a mutually offset state, the multilayer mat may be bent or the multilayer mat may be inserted in a gap having a certain distance. Even when pressed in, the number of places where the anchor effect is exhibited increases, so stress does not concentrate easily, and displacement or peeling between the layers is less likely to occur.

In the multilayer mat of the present invention, in the cross section perpendicular to the main surface of the mat including the holes, the holes are preferably formed in a curved shape.
In the cross section perpendicular to the main surface of the mat including the holes of the multilayer mat of the present invention, when the holes are formed in a curved shape, the anchor effect is further increased, and misalignment or peeling between layers is more generated. It becomes difficult to do.

In the multilayer mat of the present invention, it is desirable that the adhesive penetrates to a depth of 0.1 to 5.0 mm from the surface of the mat.
In the multilayer mat of the present invention, when the adhesive penetrates to a depth of 0.1 to 5.0 mm from the surface of the mat, the mats present above and below the adhesive layer are adhered with a sufficient adhesive force. Thus, it is possible to prevent misalignment and peeling between layers.

In the multilayer mat of the present invention, when the adhesive does not penetrate only to a depth of less than 0.1 mm from the surface of the mat, the adhesive layer does not sufficiently adhere to the mat, and therefore, the misalignment or peeling between layers Is more likely to occur. On the other hand, when the adhesive penetrates to a depth of more than 5.0 mm from the surface of the mat, the proportion of the portion of the mat made of the inorganic fiber having flexibility becomes small, and a multilayer mat lacking flexibility is obtained. .

In the multilayer mat of the present invention, the adhesive layer preferably comprises an inorganic adhesive and / or an organic adhesive.
In the multilayer mat of the present invention, when the adhesive is made of an inorganic adhesive, it has heat resistance, so that the adhesive layer does not disappear even under high temperature, and high adhesive strength can be maintained.
In addition, when the adhesive is an organic adhesive, the multilayer mat can be pressed into a gap having a predetermined distance, and then the adhesive layer can be eliminated by heating, so that the multilayer mat is fully flexible as a whole. It can be done.

In the multilayer mat of the present invention, the inorganic adhesive is desirably at least one selected from the group consisting of an alumina sol and a silica sol.
In the multilayer mat of the present invention, the multilayer adhesive is a multilayer that adheres to a plurality of layers when the inorganic adhesive is at least one selected from the group consisting of an alumina sol and a silica sol, so that multilayer is less likely to peel or shift. It can be a mat.

In the multilayer mat of the present invention, it is desirable that the adhesive filling the inside of the holes is filled with the holes to a depth of 0.1 to 5.0 mm from the outermost surface of the mat.
In the multilayer mat of the present invention, when the adhesive filling the inside of the holes fills the holes to a depth of 0.1 to 5.0 mm from the outermost surface of the mat, the anchor effect becomes larger, and the interlayer It becomes a multilayer mat that is less likely to peel off or shift.
In the present specification, the outermost surface of the mat means the surface position of the mat closest to the opposing mat when the mat on which the adhesive layer is formed is cut in a direction perpendicular to the main surface of the mat and observed. .

In the multilayer mat of the present invention, when the adhesive filling the inside of the hole is less than 0.1 mm from the outermost surface of the mat, the depth of the adhesive filling the inside of the hole is too shallow Therefore, it is difficult for the anchor effect to be exhibited, and delamination and misalignment between layers are likely to occur. On the other hand, if the adhesive filling the inside of the holes is more than 5.0 mm from the outermost surface of the mat, the anchor effect of the adhesive layer filling the inside of the holes does not change much, and the adhesive needs It is uneconomical as the volume increases.

In the multilayer mat of the present invention, the number of holes per 100 cm ² of the main surface of the mat is desirably 1000 to 2500.
In the multilayer mat of the present invention, when the number per 100 cm ² of the main surface of the mat of the holes is 1000 to 2500, the anchor effect of the adhesive layer filling the inside of the holes is sufficiently exhibited, and more layers are formed It becomes difficult to generate peeling and gap.

In the multilayer mat of the present invention, when the number of holes per 100 cm ² of the main surface of the mat is less than 1000, the anchor effect of the adhesive layer filling the inside of the holes is hardly exhibited sufficiently. It becomes easy to generate peeling and gap. On the other hand, if the number of holes per 100 cm ² of the main surface of the mat exceeds 2500, the anchor effect of the adhesive layer filling the inside of the holes does not change much, and the cost for forming the holes increases. It becomes uneconomical.

In the multilayer mat of the present invention, the holes are preferably formed by needle punching.
In the multilayer mat of the present invention, when the holes are formed by needle punching, the holes are less likely to be peeled off or shifted by filling the holes with the adhesive layer, and inorganic fibers are formed by needle punching. By entanglement, it is possible to strengthen the entanglement of the inorganic fibers and to obtain a multilayer mat with high tensile strength.

In the multilayer mat of the present invention, the inorganic fibers are desirably at least one selected from the group consisting of alumina fibers, silica fibers, alumina-silica fibers, mullite fibers, biosoluble fibers and glass fibers.

In the multilayer mat of the present invention, when the inorganic fiber is at least one selected from the group consisting of alumina fiber, silica fiber, alumina-silica fiber, mullite fiber, biosoluble fiber and glass fiber, heat resistance, Properties such as wind resistance can be sufficiently satisfied.

The method for producing a multilayer mat according to the present invention is a method for producing the multilayer mat, wherein an adhesive is applied to the main surface including the holes of a mat of a plurality of inorganic fibers having a plurality of holes formed on the main surface. A surface adhesive layer forming step of forming an adhesive layer on the main surface of the mat and the inside of the hole by applying and drying, and a plurality of the surface adhesive layer on the main surface and the inside of the hole An interlayer adhesive layer for bonding surface adhesive layers to each other by further applying an adhesive to the main surfaces of mats which are to be opposed to each other by laminating and laminating a plurality of mats. And an interlayer adhesive layer forming step of forming

According to the method for producing a multilayer mat of the present invention, an adhesive is applied to the main surface including the holes of the mat consisting of a plurality of inorganic fibers having a plurality of holes formed in the main surface, and a surface adhesive layer The above-mentioned interlayer adhesive layer is further formed to form an adhesive layer consisting of a surface adhesive layer and an interlayer adhesive layer, so the adhesive penetrates the inside of the mat too much, and the mat itself It is possible to prevent the loss of flexibility and to form a multilayer mat having appropriate flexibility in which an adhesive layer is formed to bond the upper and lower mat layers with sufficient adhesion.

In the method of manufacturing a multilayer mat according to the present invention, when laminating the plurality of mats, the mats may be laminated so that the holes formed in the mats facing each other are arranged in a mutually offset state. desirable.

In the method of manufacturing a multilayer mat of the present invention, when laminating the plurality of mats, the mats are laminated such that the holes formed in the mats facing each other are arranged in a mutually offset position. The manufactured multilayer mat has a large number of places where the anchor effect is exhibited, and it is difficult for stress to be concentrated, so that displacement or peeling between the layers is less likely to occur.

In the method for producing a multilayer mat of the present invention, the adhesive layer preferably comprises an inorganic adhesive and / or an organic adhesive.

In the method for producing a multilayer mat of the present invention, when the adhesive layer is made of an inorganic adhesive, the adhesive layer has heat resistance, so the adhesive layer does not disappear even under high temperature, and high adhesive strength is achieved. Can be maintained.
In addition, when the adhesive is an organic adhesive, the multilayer mat can be pressed into a gap having a predetermined distance, and then the adhesive layer can be eliminated by heating, so that the multilayer mat is fully flexible as a whole. can do.

In the method of producing a multilayer mat of the present invention, the inorganic adhesive is desirably at least one selected from the group consisting of an alumina sol and a silica sol.

In the method for producing a multilayer mat of the present invention, when the inorganic adhesive is at least one selected from the group consisting of alumina sol and silica sol, by bonding a plurality of layers, peeling is more likely to occur and displacement occurs more It is possible to make it difficult to make a multilayer mat.

In the method of manufacturing a multilayer mat according to the present invention, it is desirable that the plurality of holes of the plurality of mats are formed by needle punching.

In the method of manufacturing a multilayer mat according to the present invention, if the plurality of holes of the plurality of mats are formed by needle punching, the holes are filled with the adhesive layer, whereby peeling or misalignment between layers is unlikely to occur. In addition, by intertwining the inorganic fibers by needle punching, the entanglement of the inorganic fibers can be strengthened and a multilayer mat having high tensile strength can be obtained.

FIG. 1 is a cross-sectional view schematically showing an example of the multilayer mat of the present invention. FIG. 2 is a cross-sectional view schematically showing another example of the multilayer mat of the present invention. 3 (a) to 3 (c) are cross-sectional views schematically showing the steps of the method for producing a multilayer mat of the present invention. 4 (a) to 4 (d) are explanatory views schematically showing a method of manufacturing a multilayer mat according to the first embodiment. 5 (a) to 5 (c) are explanatory views schematically showing a method of measuring the peel strength of the multilayer mat according to Example 1. FIG. FIG. 6 is a graph showing the evaluation results of peel strength. FIG. 7 is a photograph of the two mats after the peeling test of the multilayer mat according to Example 1 was performed. FIG. 8 is a photograph of the two mats after the peeling test of the multilayer mat according to Comparative Example 1 was performed. FIG. 9 is a photograph of the two mats after the peeling test of the multilayer mat according to Comparative Example 2 was performed.

(Detailed Description of the Invention)
Hereinafter, the multilayer mat of the present invention will be specifically described. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without departing from the scope of the present invention.

The multilayer mat of the present invention is a multilayer mat in which a plurality of mats made of inorganic fibers are laminated,
Between the mats, an adhesive layer for bonding the mats is formed, a plurality of holes are formed on the main surfaces of the mats facing each other, and the adhesive constituting the adhesive layer is the above-described adhesive. It is characterized in that the inside of the hole is filled.

FIG. 1 is a cross-sectional view schematically showing an example of the multilayer mat of the present invention.
In the multilayer mat 10 of the present invention shown in FIG. 1, two upper layer mats 11 and lower layer mats 12 made of inorganic fibers are laminated, and between the upper layer mat 11 and the lower layer mat 12, the adhesive layer 13 is formed. It is formed.

Further, a plurality of holes 11b and 12b are formed in the two main surfaces 11a and 12a where the upper layer mat 11 and the lower layer mat 12 face each other, and the adhesive constituting the adhesive layer 13 is the holes 11b and 12b. The inside of the is filled.

Therefore, the adhesive filling the inside of the hole exerts an anchor effect, and even when the multilayer mat 10 is bent or the multilayer mat 10 is pushed into a gap having a certain distance, misalignment or peeling occurs between the layers. It is difficult, and the function required as a mat can be sufficiently exhibited in the holding of the exhaust gas treating body, the soundproofing material and the like.

Although FIG. 1 shows a multilayer mat in which two mats are laminated, the number of mats to be laminated is not limited to two, and may be three, four, five, etc. Although it is good, two or three sheets are desirable.

Next, the mat constituting the multilayer mat of the present invention will be described.
The mat is made of inorganic fibers.
The inorganic fiber constituting the mat is not particularly limited, but is preferably at least one selected from the group consisting of alumina fiber, silica fiber, alumina-silica fiber, mullite fiber, biosoluble fiber and glass fiber .
When the above-mentioned inorganic fiber is at least one selected from the group consisting of alumina fiber, silica fiber, alumina silica fiber and mullite fiber, it is excellent in heat resistance, so when the mat is exposed to high temperature Even if it is present, no alteration or the like occurs and the function as a mat can be sufficiently maintained.

The alumina fiber may contain, for example, additives such as calcia, magnesia and zirconia in addition to alumina.
The composition ratio of alumina-silica fibers, a weight _{ratio, Al 2 O 3: SiO 2} = 60: 40~99: a desirably _{1, Al 2 O 3: SiO} 2 = 70: 30~74: 26 It is more desirable to have.

The glass fiber is a glassy fiber mainly composed of silica and alumina, and optionally containing calcia, titania, zinc oxide and the like in addition to alkali metals.

The average fiber length of the inorganic fibers is preferably 5 to 150 mm, and more preferably 10 to 80 mm.
If the average fiber length of the inorganic fibers is less than 5 mm, the fiber length of the inorganic fibers is too short, and the interlacing of the inorganic fibers becomes insufficient, and the multilayer mat is easily broken when mounted on a member having a curved surface. When the average fiber length of the inorganic fibers exceeds 150 mm, the fiber length of the inorganic fibers is too long, so the number of fibers constituting the mat decreases, and the density of the mat decreases. As a result, the shear strength of the mat is reduced.

It is desirable that an oil-like binder and an organic binder be attached to the inorganic fibers constituting the mat.
The organic binder can be attached to the inorganic fibers constituting the mat by attaching the organic binder in the organic binder-containing emulsion to the mat and drying it.
It does not specifically limit as an organic binder to be used, For example, the resin component or rubber component contained in an acrylic resin emulsion, acrylate type latex, rubber-type latex etc. is mentioned.
It does not specifically limit as an oil-like binder to be used, For example, a silicone oil is mentioned.

When an organic binder or an oil-like binder is attached to the above-mentioned inorganic fibers, the fibers are easily entangled, which can increase shear stress and the like. For example, when pushing a multilayer mat into a gap having a certain distance, misalignment occurs. And peeling hardly occur.

It is desirable that an inorganic binder component such as silica sol or alumina sol be attached to the inorganic fibers constituting the mat, if necessary.
By attaching an inorganic binder component such as silica sol or alumina sol, the inorganic fibers can be easily caught together, and the shear strength of the mat can be increased.

A plurality of holes are formed in the mutually opposing main surfaces of the laminated mats.
The method of forming the holes is not particularly limited. For example, the protrusions may be pierced into the mat or air may be jetted toward the mat using an air gun or the like. Although it may be used, a method of forming holes by needle punching is desirable.
In this case, the holes become through holes penetrating the mat. In addition, a needle punching process means the process which penetrates the mat | matte with the needle which has a barb in a front-end | tip part. A needle without barbs at the tip may be used.

When needle punching treatment is performed, not only through holes can be formed, but also inorganic fibers can be entangled, entanglement between inorganic fibers can be strengthened, tensile strength of the mat can be increased, and shape of the mat can be easily maintained. can do.

The holes may be so-called bottomed holes having a bottom or may be through holes, but are preferably through holes. When the through holes are formed, the depth of the holes filled with the adhesive can be made sufficiently deep, and an adhesive layer having a large anchor effect can be formed.

In the multilayer mat of the present invention, the number of holes per 100 cm ² of the main surface of the mat is desirably 1000 to 2500.
In the multilayer mat of the present invention, when the number per 100 cm ² of the main surface of the mat of the holes is 1000 to 2500, the anchor effect of the adhesive layer filling the inside of the holes is sufficiently exhibited, and more layers are formed It becomes difficult to generate peeling and gap.

Although the shape of the said mat | matte is not specifically limited, Flat form is desirable, and it is desirable that the thickness is 2-30 mm.
If the thickness of the mat is less than 2 mm, the thickness is too thin, and the holding ability to hold the exhaust gas treating body and the like is reduced. On the other hand, when the thickness of the mat exceeds 30 mm, the flexibility is reduced, the deformation of the member having a curved surface occurs, and the sound absorption, the vibration reduction and the vibration suppression function are significantly reduced.

In the multilayer mat of the present invention, as shown in FIG. 1 as well, it is desirable that the plurality of holes formed in mats facing each other be formed in a mutually offset state.
In the multilayer mat of the present invention, when the holes formed in the mats facing each other are formed in a mutually offset position, the multilayer mat is bent or the multilayer mat is pushed into a gap having a predetermined distance. Also in this case, since the number of places where the anchor effect is exhibited increases, it is difficult for stress to be concentrated, and it becomes difficult for displacement and peeling to occur between the respective layers.

Although the bulk density of the said mat | matte is not specifically limited, It is desirable that it is 0.05-0.30 g / cm < ³ >. When the bulk density of the mat is less than 0.05 g / cm ³ , the entanglement of the inorganic fibers is weak and the inorganic fibers are easily peeled off, so it is difficult to keep the shape of the mat in a predetermined shape. On the other hand, if the bulk density of the mat exceeds 0.30 g / cm ³ , the mat becomes hard, the mountability to a member having a curved surface decreases, deformation of other members occurs, sound absorption, vibration control, vibration control Function is significantly reduced.

Next, in the multilayer mat of the present invention, an adhesive layer for bonding mats will be described.
The adhesive layer is composed of an inorganic adhesive and / or an organic adhesive.

The inorganic adhesive is not particularly limited, and examples of the inorganic adhesive include sodium silicate, silica sol, alumina sol, zirconia sol, and sitania sol. Among the above-mentioned inorganic adhesives, at least one selected from the group consisting of alumina sol and silica sol is desirable.

In the multilayer mat of the present invention, the multilayer adhesive is a multilayer that adheres to a plurality of layers when the inorganic adhesive is at least one selected from the group consisting of an alumina sol and a silica sol, so that multilayer is less likely to peel or shift. It can be a mat.

Examples of the organic adhesive include an epoxy resin-based adhesive that can be dispersed in water, a polyvinyl acetate-based adhesive, a nitrile rubber-based adhesive, a phenol resin-based adhesive that can be dissolved in a solvent, and a vinyl acetate-based adhesive Chloroprene rubber adhesives, epoxy resin adhesives which cure by chemical reaction, acrylic resin adhesives, silicone rubber adhesives and the like can be mentioned.

When the adhesive is made of an organic adhesive, the multilayer mat can be pressed into a gap having a predetermined distance and then the adhesive layer can be eliminated by heating to form a multilayer mat having high flexibility as a whole. Can.

In the multilayer mat of the present invention, it is desirable that the adhesive filling the inside of the holes is filled with the holes to a depth of 0.1 to 5.0 mm from the outermost surface of the mat.
In the multilayer mat of the present invention, when the adhesive filling the inside of the holes fills the holes to a depth of 0.1 to 5.0 mm from the outermost surface of the mat, the anchor effect becomes larger, and the interlayer It becomes a multilayer mat that is less likely to peel off or shift.

In the multilayer mat of the present invention, the thickness of the thinnest part of the adhesive layer in the part not containing holes may be 0.1 to 2.0 mm, but is 0.3 to 2.0 mm. desirable. If the thickness of the thinnest part of the adhesive layer is 0.3 to 2.0 mm, the upper mat layer can be bonded with sufficient strength.

In addition, as shown in FIG. 1, in the multilayer mat 10, the plurality of holes 11b and 12b formed in the upper layer mat 11 and the lower layer mat 12 opposed to each other are formed in a mutually offset state. Is desirable.
When the plurality of holes 11b and 12b formed in the upper layer mat 11 and the lower layer mat 12 opposed to each other are formed in a mutually shifted position, the number of places for exhibiting an anchor effect is increased, so stress is generated. Is difficult to concentrate, and it is difficult for displacement and peeling to occur between each layer.

FIG. 2 is a cross-sectional view schematically showing another example of the multilayer mat of the present invention.
In the multilayer mat 20 of the present invention shown in FIG. 2, two upper layer mats 21 and lower layer mats 22 made of inorganic fibers are laminated, and between the upper layer mat 21 and the lower layer mat 22, the adhesive layer 23 is formed. It is formed.

A plurality of holes 21b and 22b are formed in the two main surfaces 21a and 22a where the upper layer mat 21 and the lower layer mat 22 face each other, and the adhesive constituting the adhesive layer 23 is the holes 21b and 22b. The inside of the is filled.

The multilayer mat 20 shown in FIG. 2 is different from the multilayer mat 10 shown in FIG. 1 in that a plurality of holes 21 b and 22 b are formed in a curved shape.
Thus, if the holes 21b and 22b are formed in a curved shape in the cross section perpendicular to the main surface of the multilayer mat 20 including the holes, the holes are easily hooked to the mat, so that the anchor effect is increased and each layer Makes it more difficult for displacement and peeling to occur.

Next, the method for producing the multilayer mat of the present invention will be described.
The method for producing a multilayer mat according to the present invention is a method for producing the multilayer mat according to the present invention described above, wherein the main surface including the holes of the mat comprising a plurality of inorganic fibers having a plurality of holes formed on the main surface. A surface adhesive layer forming step of forming an adhesive layer on the main surface of the mat and the inside of the pores by applying an adhesive on the surface and drying the surface adhesive on the main surface and the inside of the pores When laminating a plurality of mats having a layer, an adhesive is further applied to the main surfaces of the mats that are to be opposed to each other by the lamination, and the surface adhesive layers are adhered to each other by laminating a plurality of mats. And an interlayer adhesive layer forming step of forming an interlayer adhesive layer.

In the method for producing a multilayer mat of the present invention, first, a mat containing inorganic fibers is prepared.
The mat can be obtained by various methods, and can be produced, for example, by the following method.

First, a viscous mixture for spinning containing a raw material to be an inorganic substance such as alumina and silica is prepared, and then the mixture for spinning is spun to produce an inorganic fiber precursor, and subsequently, the inorganic fiber precursor is compressed. Then, a continuous sheet-like material having a predetermined size is produced, subjected to needle punching treatment, and then subjected to firing treatment, whereby a mat made of inorganic fibers can be produced.

3 (a) to 3 (c) are cross-sectional views schematically showing the steps of the method for producing a multilayer mat of the present invention.
In the method for producing a multilayer mat according to the present invention, the number of mats to be laminated is not particularly limited, and may be three or more. In FIG. 3, two mats are used as an example. Shows an example of producing a multilayer mat.

In the method of manufacturing a multilayer mat according to the present invention, as shown in FIG. 3A, first, as a surface adhesive layer forming step, two inorganic fibers in which a plurality of holes are formed in the main surfaces 11a and 12a. The adhesive is applied to the main surfaces 11a and 12a of the upper layer mat 11 and the lower layer mat 12 and dried to adhere the surface to the main surfaces 11a and 12a of the upper layer mat 11 and the lower layer mat 12 including the insides of the holes 11b and 12b. The agent layers 130a and 130b are formed.

It should be noted in the surface adhesive layer forming step that an adhesive having a high viscosity is used or an oil-like binder is attached to the fibers constituting the mat so that the adhesive does not penetrate deep inside the mat. This prevents the adhesive from penetrating inside, and forms surface adhesive layers 130a and 130b only on the portion close to the surface of the mat.

As drying conditions at the time of forming a surface adhesive bond layer, drying temperature is normal temperature -80 degreeC, and 120 to 180 minutes of drying time are desirable.

Next, as shown in FIG. 3B, when laminating two upper layer mats 11 and lower layer mats 12 having surface adhesive layers 130a and 130b on the main surfaces 11a and 12a as an interlayer adhesive layer forming step. An adhesive is further applied to one of the main surfaces 11a and 12a of the upper layer mat 11 and the lower layer mat 12 which will be mutually opposed by lamination, to form a coated layer 130c ', and two upper layer mats are formed. 11, the lower layer mat 12 is laminated, and the applied adhesive forms an interlayer adhesive layer 130c to which the surface adhesive layers 130a and 130b are adhered. Thereby, as shown in FIG. 3C, the adhesive layer 13 composed of the surface adhesive layers 130a and 130b and the interlayer adhesive layer 130c is formed between the two mats.
At this time, the coating layer 130 c ′ may be formed on both the two upper layer mats 11 and the lower layer mat 12.

In the method for producing a multilayer mat of the present invention, since the surface adhesive layers 130a and 130b are first formed, the adhesive force is applied to one or both of the main surfaces of the mats facing each other. In order to provide sufficient strength, even if the adhesive is applied, the adhesive can be prevented from penetrating deep into the mat or deep inside the holes, and adhesion of an appropriate thickness The agent layer 13 can be formed.

As drying conditions after an adhesive bond layer formation process, drying temperature is normal temperature -80 degreeC, and drying time is desirable for 24 to 72 hours.
The number of mats to be laminated is not particularly limited, but two or three are desirable.
Thereafter, if necessary, a cutting step of cutting the multilayer mat into a predetermined shape may be performed.

The multilayer mat of the present invention holds a heat insulating material or soundproofing material such as each member of a vehicle or equipment, a heat insulating material serving as soundproofing, a holding sealing material for holding an exhaust gas purification filter of a diesel engine vehicle, and an exhaust gas purification catalytic converter It can be used as a holding sealing material etc.

Below, the effect of the multilayer mat of this invention is demonstrated.
(1) In the multilayer mat of the present invention, a plurality of holes are formed on the main surfaces of the mats facing each other, and the adhesive constituting the adhesive layer fills the inside of the holes. The adhesive layer inside the hole exerts an anchor effect, and even when the multilayer mat is bent or the multilayer mat is pushed into a gap having a certain distance, it is difficult for displacement and peeling to occur between layers, and the exhaust gas treating body In holding etc., the function as a mat can fully be exhibited.

(2) In the multilayer mat of the present invention, when the holes formed in the mats facing each other are formed in a mutually shifted position, the multilayer mat may be bent or a multilayer may be formed in a gap having a certain distance. Even when the mat is pushed in, the number of places exerting the anchor effect is increased, so that stress is hard to concentrate, and displacement and peeling are less likely to occur between the layers.

(3) In the multilayer mat of the present invention, when the holes are formed in a curved shape in a cross section perpendicular to the main surface of the mat including the holes, the anchor effect is further enhanced, and the misalignment between the layers Peeling is less likely to occur.

(4) In the multilayer mat of the present invention, the inorganic adhesive is used, and the inorganic adhesive is at least one selected from the group consisting of an alumina sol and a silica sol by bonding a plurality of layers. Can be a multilayer mat that is less likely to peel or shift.

(5) In the method for producing a multilayer mat of the present invention, an adhesive is applied to the main surface including the holes of the mat consisting of a plurality of inorganic fibers having a plurality of holes formed in the main surface, and a surface adhesive By forming an interlayer adhesive layer after forming the layer, the adhesive penetrates too much into the inside of the mat and the mat itself can be prevented from becoming hard and losing its flexibility, the upper and lower mats It can be a multilayer mat with adequate flexibility in which an adhesive layer is formed to adhere the layers with sufficient adhesion.

(Example)
Hereinafter, the example which indicated the present invention more concretely is shown. The present invention is not limited to these examples.

Example 1
(A) Needle Punched Mat Preparation Step A needle punched mat was prepared according to the following procedure.
(A-1) Spinning step Inorganic fibers after firing of an aqueous solution of basic aluminum chloride prepared so that the Al content is 70 g / l and Al: Cl = 1: 1.8 (atomic ratio) The silica sol is blended so that the composition ratio in this case is Al ₂ O ₃ : SiO ₂ = 72: 28 (weight ratio), and an appropriate amount of organic polymer (polyvinyl alcohol) is further added to prepare a solution for alumina fiber precursor Was prepared.
The obtained mixture was concentrated to form a spinning solution, and the spinning mixture was spun by a blowing method to prepare an alumina fiber precursor having an average fiber diameter of 5.1 μm.

(A-2) Compression step The alumina fiber precursor obtained in the above step (a-1) was laminated and compressed to prepare a laminated sheet.

(A-3) Needle punching treatment step The needle punching treatment is performed continuously on the laminated sheet obtained in the above step (a-2), and the density of needle marks is 21 pieces / cm ^2. Was produced.

(A-4) Firing step The needle punching treated body obtained in the above step (a-3) is continuously fired at a maximum temperature of 1250 ° C., and an inorganic fiber containing 72 parts by weight of alumina and silica: 28 parts by weight A sintered sheet comprising The average fiber diameter of the inorganic fiber was 5.1 μm, and the minimum value of the inorganic fiber diameter was 3.2 μm. The sheet-like material thus obtained had a bulk density of 0.15 g / cm ³ and a basis weight of 1050 g / m ² .

(A-5) Silicone oil adhesion process A silicone oil is adhered to the surface of the sheet for the purpose of preventing scattering of fibers, reducing bromination during combustion and water repellency, and cut into dimensions of 600 mm × 400 mm for adhesion It was a mat. Two bonding mats were prepared.

(B) Adhesive solution preparation process First, an alumina sol (Nissan Chemical Industry Co., Ltd.) is prepared by diluting food dye blue manufactured by Kyoritsu Foods Co., Ltd. with tap water and adjusting the pigment concentration to 1.4%. A trade name: 520-A (solids concentration: 20 wt%) was prepared to have a ratio of colored water: alumina sol = 1: 25.9, and the adhesive solution was prepared by stirring.

(C) Surface Adhesive Layer Forming Process FIGS. 4A to 4D are explanatory views schematically showing a method of manufacturing a multilayer mat according to the first embodiment.
The adhesive solution is put into a spray gun, and as shown in FIG. 4 (a), the solid content weight is 173.5 g / m on one main surface 31a of the two adhesive mats 31 and 32 with less unevenness. ^The adhesive solution 35 was sprayed by a spray gun 36 so as to be ² to form a coated layer, and the coated layer was stored in a drying rack for 3 hours or more, and was naturally dried to form a surface adhesive layer 330a. The thickness of the surface adhesive layer 330a was 30 mm. In FIG. 4A, of the two bonding mats 31 and 32, only one bonding mat 31 is shown.

(D) Coating step of adhesive solution for interlayer adhesive layer Next, the adhesive mat 31 having the surface adhesive layer formed thereon is taken out from the drying rack, and the adhesive solution prepared in the adhesive solution preparing step is Using the spray gun contained, as shown in FIG. 4 (b), on the side on which the surface adhesive layer 330 a of the bonding mat 31 is formed and on the side on which another surface adhesive layer is formed, The adhesive solution 35 was sprayed by a spray gun 36 so that the solid content weight was a uniform coating amount of 365.0 g / m ² to form a coated layer, and then cut to a width of 5 cm at one end of the coated surface The vinyl sheet 37 was placed.

(E) Bonding step Next, as shown in FIG. 4C, the other bonding mat 32 is also taken out from the drying rack, and the surface adhesive layer of the bonding mat 32 and the bonding that has been coated are completed. The two bonding mats 31 and 32 are pasted together so that the coating layer of the mat 31 comes into contact, and as shown in FIG. 4D, the weight 38 is set to have a gravity of 0.045 kPa. The multi-layer mat according to Example 1 on which an adhesive layer consisting of an interlayer adhesive layer and a surface adhesive layer was formed was finished by carrying on the drying shelf for 10 seconds and naturally drying for at least 48 hours or more.

(Comparative example 1)
(A) Bonding Mat Preparation Step The steps (a-1) to (a-5) were performed in the same manner as in Example 1 to prepare two bonding mats.

(B) Adhesive solution application step Next, the adhesive solution prepared in the same manner as in Example 1 is put into a spray gun, and the solid content weight is 173.5 g on one surface of the one bonding mat having less unevenness. The coating layer was formed by spraying with a spray gun so as to be 1 / m ² and placed in an oven set at 80 ° C. for about 60 minutes.
After drying, the adhesive mat on which the adhesive layer is formed is taken out and cooled, and then a spray gun containing the adhesive solution prepared in the above adhesive solution preparation step is used to spray on the side on which the adhesive layer is formed. After forming the coating layer by spraying the adhesive solution so that the solid content weight becomes a uniform coating amount of 365.0 g / m ^{2 by} a gun to form a coating layer, the width of 5 cm is applied to one end of the coating surface as in Example 1. The cut vinyl sheet was placed.

(C) Bonding process After that, another mat not coated with adhesive is laminated on the mat finished coating and bonded, and the weight set to 0.045 kPa is set for 10 seconds. The product was placed and placed in an oven set at 80 ° C. for about 180 minutes to complete the production of the multilayer mat according to Comparative Example 1.

(Comparative example 2)
(A) Sheet-Making Mat Preparation Step (a-1) Mixed Liquid Preparation Step First, the composition ratio of the inorganic fiber after firing to the basic aluminum chloride aqueous solution is Al ₂ O ₃ : SiO ₂ = 72: 28 (weight The silica sol was blended so as to obtain the ratio, and an appropriate amount of organic polymer (polyvinyl alcohol) was further added to prepare a mixed solution.
The obtained mixture was concentrated to a spinning mixture, and the spinning mixture was spun by a blowing method to produce an inorganic fiber precursor. Next, the obtained inorganic fiber precursor was compressed to produce a continuous sheet. Thereafter, the sheet-like material was placed in a heating furnace and subjected to a baking treatment to produce an inorganic fiber aggregate.
Next, the inorganic fiber aggregate is wet-opened using a mixer, an organic binder of 9% by weight in terms of solid content is added to the fiber, and an inorganic binder of 1% by weight in terms of solid content is added to the fiber, It stirred. Thereafter, a coagulant was added and the mixture was stirred to prepare a mixture.

(A-2) Dewatering Step Next, the mixed solution was poured into a molding machine having a mesh for filtration formed on the bottom, and then water in the mixed solution was dewatered through the mesh to prepare a raw material sheet. .

(A-3) Heating and pressurizing step Subsequently, the obtained raw material sheet is taken out from the molding machine, compressed to a thickness of 8 mm using a press, and simultaneously heated to 150 ° C. by a hot plate and hot air ventilation. It was dried by heating and cut to a size of 600 mm × 400 mm to make a mat for bonding. At that time, the amount of fibers was adjusted so that the weight per unit area would be 1500 g / m ² . Two bonding mats were prepared.

(B) Adhesive Solution Coating Step and Bonding Step Thereafter, in the same manner as in Comparative Example 1, the adhesive solution coating step and the bonding step were carried out to produce a multilayer mat according to Comparative Example 2.

(Measurement of peel strength by tensile test)
5 (a) to 5 (c) are explanatory views schematically showing a method of measuring the peel strength of the multilayer mat according to Example 1. FIG.
First, as shown in FIG. 5A, the vinyl sheet 37 was removed from the multilayer mat 30 according to the first embodiment. Next, as shown in FIG. 5 (b), a mat 30A of 210 mm × 80 mm in size including the non-adhered portions 301 and 302 of 5 cm in width intentionally made of a vinyl sheet 37 was cut out. .
Next, as shown in FIG. 5C, using a tensile test (product name: 5967 manufactured by Instron Corp.), one non-adhered portion 301 is clamped to the clamp 41 above the tester, and the tester lowers. The peel strength was measured by clamping the other non-adhered portion 302 to the clamp 42 and pulling at a crosshead speed of 1 cm / min. The above test was conducted until the entire surface was broken, and the peel strength was evaluated by recording the maximum load at the time of the test.
The peel strength was similarly measured for the multilayer mats according to Comparative Example 1 and Comparative Example 2.

FIG. 6 is a graph showing the evaluation results of peel strength.
Moreover, FIG. 7 is the photograph which image | photographed 2 sheets of mats after performing the peeling test of the multilayer mat which concerns on Example 1, and FIG. 8 is after performing the peeling test of the multilayer mat which concerns on the comparative example 1. FIG. 9 is a photograph of the two mats after the peeling test of the multilayer mat according to Comparative Example 2 was performed.

As shown in FIG. 6, while the peel strength of the multilayer mat according to Example 1 was as high as 4.86 N, the peel strength of the multilayer mat according to Comparative Example 1 was 0.98 N, and Comparative Example 2 was The peel strength of the multilayer mat according to Example 1 was 2.53 N, and the peel strength of the multilayer mat according to Example 1 was sufficiently high as compared with Comparative Examples 1 and 2.

Further, as apparent from comparison of FIGS. 7 to 9, the multilayer mat according to Example 1 does not peel off at the adhesive layer portion but peels off at the mat portion because the adhesive layer has high strength. On the other hand, in the multilayer mats according to Comparative Examples 1 and 2, peeling occurred in the portion of the adhesive layer because the peeling strength of the adhesive was insufficient.

Thus, in comparison with the multilayer mats according to Comparative Examples 1 and 2, the multilayer mat according to Example 1 has high peel strength, and bends the multilayer mat or presses the multilayer mat into a gap having a predetermined distance. Also in the case, it was found that misalignment and peeling were less likely to occur between layers.

10, 20, 30 Multilayer Mats 11, 21, 31 Upper Mats 11a, 12a, 21a, 22a, 31a Main Surfaces 11b, 12b, 21b, 22b Holes 12, 22 Lower Mats 13, 23 Adhesive Layers 31, 32 Adhesive Mats 35 adhesive solution 36 spray gun 37 plastic sheet 38 outer cover 41, 42 grip 301, 302 non-adhered parts 130a, 130b, 330a surface adhesive layer 130c interlayer adhesive layer 130c 'coated layer

Claims (15)

A multilayer mat in which a plurality of mats made of inorganic fibers are laminated,
Between the mats, an adhesive layer is formed to bond the mats together,
A plurality of holes are formed on the main surfaces of the mats facing each other,
The multilayer mat characterized in that an adhesive constituting the adhesive layer fills the inside of the holes. The multilayer mat according to claim 1, wherein the plurality of holes formed in the mats facing each other are formed in a state in which the positions are shifted from each other. The multilayer mat according to claim 1, wherein the holes are formed in a curved shape in a cross section perpendicular to the main surface of the mat including the holes. The multilayer mat according to any one of claims 1 to 3, wherein the adhesive penetrates to a depth of 0.1 to 5.0 mm from the surface of the mat. The multilayer mat according to any one of claims 1 to 4, wherein the adhesive layer comprises an inorganic adhesive and / or an organic adhesive. The multilayer mat according to claim 5, wherein the inorganic adhesive is at least one selected from the group consisting of alumina sol and silica sol. The multilayer mat according to any one of claims 1 to 6, wherein the adhesive filling the inside of the holes fills the holes to a depth of 0.1 to 5.0 mm from the outermost surface of the mat. The multilayer mat according to any one of claims 1 to 7, wherein the number of the holes per 100 cm ² of the main surface of the mat is 1000 to 2500. The multilayer mat according to any one of claims 1 to 8, wherein the holes are formed by needle punching. The inorganic fiber is at least one selected from the group consisting of alumina fiber, silica fiber, alumina-silica fiber, mullite fiber, bio-soluble fiber and glass fiber according to any one of claims 1 to 9. Multilayer mat. A method of manufacturing a multilayer mat according to any one of claims 1 to 10, wherein
Adhesive is applied to the main surface of the mat and the inside of the holes by applying an adhesive to the main surface including the holes of the mat made of a plurality of inorganic fibers having a plurality of holes formed on the main surface and drying the adhesive. A surface adhesive layer forming step of forming an adhesive layer;
When laminating a plurality of mats having the surface adhesive layer on the main surface and the inside of the holes, an adhesive is further applied to the main surfaces of the mats to be opposed to each other by lamination, and a plurality of mats are formed An interlayer adhesive layer forming step of forming an interlayer adhesive layer bonding the surface adhesive layers to each other by laminating, and a method of producing a multilayer mat. The method for manufacturing a multilayer mat according to claim 11, wherein when laminating the plurality of mats, the mats are laminated such that the holes formed in the mats facing each other are arranged in a mutually offset position. The method for producing a multilayer mat according to claim 11 or 12, wherein the adhesive layer comprises an inorganic adhesive and / or an organic adhesive. The method for producing a multilayer mat according to claim 13, wherein the inorganic adhesive is at least one selected from the group consisting of alumina sol and silica sol. The method of manufacturing a multilayer mat according to any one of claims 11 to 14, wherein the plurality of holes of the plurality of mats are formed by needle punching.

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