JP3373210B2 - How to make mat-like products - Google Patents

Abstract

In a method for making a fibrous product from separate particles, an air flow (A) is used for forming a mat on an advancing forming platform (1). The particles are bonded to form the mat by means of thermally activatable binder material brought to the mat forming site such that it upon being activated through the action of heat bonds the particles to each other in the mat. Said binder material is brought to an activated state already in air flow (A) carrying the particles onto forming platform (1) by setting temperature of the air flow sufficiently high. The material forming the base of the mat in the particles is constituted of a material activatable at a higher temperature than the thermally activatable binder material.

Description

Detailed Description of the Invention   The present invention relates to a method for manufacturing a mat.

International Publication No. WO 82/03359 is
Disclosed is a method for making a formable mat from wood fibers such that the wood fibers are twisted together with the heat-bondable binder fibers that bond the wood fibers together. This mat is formed by using a dry method in a movable belt by so-called air flow (air flow), which carries fibers on the air flow belt and passes through the mat. The mat thus formed is then provided with a temperature high enough to soften the binder fibers made of a thermoplastic material into an adhesive state for bonding the wood fibers together. The gluing process of gluing the mat by passing through an oven is followed.

The use of wood fibers and other cellulosic fibers derived from plants for the production of textiles is abundantly available, easy to handle as material, non-healthy and recyclable. It is attractive when natural materials are a problem. Fibrous mats made from these fibers are also effective thermal insulators. However, this is a property that causes problems with the manufacture of the product if the aforementioned processes are to be used. When the product is processed in an oven, it is necessary to spend a considerable amount of time in the oven in order to allow the heat to also pass inside the mat-shaped product in order to bond the fibers. If the goal is to make a product of significant thickness, set the furnace time excessively to ensure that the mat adheres properly in the center of the mat when leaving the furnace. It will need to be long. Alternatively, a large increase in temperature could be envisaged, as this would cause the matte to melt either due to the melting of the thermoplastic fibers contained therein, or due to the complete dissolution as spherical drops which would not allow the fibers to adhere. They fall apart and lead to damage to the surface structure of the product. Obviously, the above process is also not feasible in terms of energy consumption.

In order to eliminate such disadvantages, Finnish patent application No. 922421 discloses a method and a device which can even make a very thick fibrous mat of wood fibers with excellent thermal insulation capacity. In this technique, a thermoplastic binder fiber, which acts as a heat-activated binder material and is twisted with plant-based cellulosic fibers, sets the temperature of the air flow high enough to form a platform. Already activated, ie softened, in the air flow that carries the fibers to. This does not impair the insulating properties of this fiber. The thermoplastic binder fibers already bond the wood fibers to one another during the production of the mat. As a matter of fact, it is basically possible to deposit the desired amount of new fibers that bind into the mat on the upper surface of the preformed mat at the site of mat production, so that it is very thick. Even the production of mats will be easier.

Although the above method is limited to the use of cellulosic fibers, this method does
e) Materials are composed of particles that are activated at higher temperatures than binder materials such as mineral fibers (“rock wool” or glass fibers) or other thermoplastic fibers, instead of cellulosic fibers that are not activated by heat. It has also been found suitable for the production of products that can.

The present invention is described in detail in the following description with reference to the accompanying drawings.

1 is a side sectional view of a mat-forming assembly included in an apparatus used in the method of the present invention, FIG. 2 is a cross-sectional view of the assembly shown in FIG. 1, and FIG. FIG. 4 is an enlarged view of details included in the aggregate shown in FIG. 1, and FIG. 4 schematically shows an operation principle regarding the entire device.

FIG. 1 shows a mat-forming assembly including a supply mechanism 11 for separated particles. This feeding mechanism is a vertical device known per se for guiding particles by air flow.
It may have either 11a or a horizontal conveyor 11b at the inlet end which may be provided with pretreatment means known per se. At the bottom end of the supply mechanism 11, a supply roll 2 having pins in a dense pattern for expression is provided. Opposite the surface of the supply roll 2 is a horizontal narrow slit orifice at the end of the first air passage 3. Below this slit orifice, the inlet for the second air passage 4 is arranged, forming a constriction point between its bottom wall and the surface of the supply roll 2. Downstream of this constriction is an air chamber 6 which extends obliquely downwards and expands, the lower end of which is blocked by an air-permeable forming platform 1. Opposite the formation platform 1 is a collection chamber 10.

The forming platform 1 is formed from a seamless belt, encircles and extends the cylinder, and is mounted transversely to the chamber 6. Downstream of chamber 6,
The forming platform intersects the second air chamber 8 and forms the bottom surface of the second air chamber.

The inlet end of the first air passage 3 is equipped with mutually parallel fans 12 for creating a uniform air flow across the entire width of the duct 6. These fans 12 are shown in FIG.
Is indicated by a broken line in. The duct 13 which serves as the inlet end of the second air passage 4 is also equipped with a fan 13, which is mounted in the second air passage 4 so as to blow the air heated by the heater 7. . The heater 7 can be, for example, a conventional gas burner.

In the mat formation process of this apparatus, the previously produced separated particles (that is, the separated individual particles) forming the basic structure of the mat are sent to the supply roll 2 by the supply mechanism. . FIG. 4 shows the subsequent mat forming process in more detail. The rotating supply roll 2 is for picking up and further transporting particles,
The pin shown in Figure 4 as the outermost layer of the feed roll
Includes 2a. Then, in the direction of rotation of the feed roll, the fibers are located at the ends of the first air passage 3 and are horizontal slit orifices extending across the width of said roll.
Reach range 3a. The high-speed air flow A1 discharged from the slit orifice releases particles from the supply roll 2 while the second air passage 4 is formed in the constriction point 2b between the bottom wall of the inlet 4a and the surface of the supply roll 2. Carry the particles across the inlet 4a. After passing the constriction point, the particles are completely released from the supply roll 2 and proceed into an air chamber 6 having a cross section extending in the direction of travel and having a width which is constant and corresponds to the width of the mat to be manufactured. This opening or spreading of the chamber is achieved in such a way that the front and rear wall surfaces extending axially of the supply roll 2, i.e. in the lateral direction of the mat to be manufactured, are separated from each other.

The second air passage 4 is used to send air as an air flow A2 into the inlet 4a. This second
The temperature of the air flow A2 is higher than the temperature of the first air flow A1 supplied through the first air passage 3. As a result of the ejector effect caused by the constriction point 2b, this air flow A2 merges into the air flow A1 and mixes with it, resulting in an air flow A which carries the particles to the outlet end of the air chamber 6. The feed rate of this higher temperature air flow A2 mixes with the particles to the extent that the temperature of the air flow A carrying the particles in the air chamber 6 allows the particles to adhere to the mat. Was done,
Sufficient to cause activation of the binder material which is activated by heat. However, this temperature is below the activation temperature of the separating particles forming the support of the mat so that no substantial change occurs in this material. The particles carried by the air flow A are (i) a composition in which a binder is present on the surface of, for example, fibrous particles made of the material forming the support of the mat as described below, or (ii) The binder is, for example, in the form of fibrous particles as described below, and the particles made of the material forming the support of the mat and the particulate binder are both separate particles and mixed. May be In the specification, the particulate binder may be referred to as particles. The binder material that can be activated by this heat is
Since it moves exposed in the air flow A in the naked state, it is considerably affected by the heat of the air. Particles of the material forming the support are formed on the forming platform 1
Above, they are adhered to each other by the bonding material. The outlet or trailing end of the air chamber 6 is blocked by a forming platform 1 which traverses the chamber and is of woven wire fibers or similar air permeable flat material. be able to. At the entrance of the conveyor, i.e. downstream of the front wall of the air chamber,
The bottom striking particles make up a rapidly bonded mat, with a continuous increase in thickness. Mats that are glued in exactly the same way are stacked on top of it. Since the created mat is porous in nature, the air flow A passes through the mat and the forming platform 1 below it and into the opposite collection chamber 10.

FIG. 1 shows the next step of the mat. A packing cylinder 14 is mounted downstream of the chamber 6 in the direction of movement of the forming platform 1, the distance of this packing cylinder from the forming platform 1 being adjustable. This packing cylinder prevents air from the air chamber from passing from the top of the mat in the conveying direction of the forming platform 1. Downstream of this packing cylinder, the forming platform 1
The mat is carried into a second air chamber 8 placed on the forming platform 1. At the upper end of the air chamber 8,
An air passage 9 is provided. Second air chamber 8
In the direction of the air flow supplied from the air passage 9 has a shape that is widened or open towards the forming platform 1, ie the chamber walls located on the inlet and outlet sides of the forming platform are separated from each other. . For example, the pressure of the air flow B supplied into the chamber can be used to further compress the mat to the desired degree to give the desired value for the density of the mat. Thus, the air flow is routed through the porous mat and the forming platform 1 supporting it from below into the second collecting chamber 15 located on the opposite side. Therefore, the temperature of the air flow B supplied into the second air chamber 8 is such that the binder fibers are in contact with the matting fibers to shape or form the mat to a desired density with permanent deformation. The temperature is such that it remains softened so that it can be deformed. Second
Downstream of the chamber 8 of the mat, the mat is transferred from the forming platform 1 onto the conveyor 16 and the bonded mat-like product (hereinafter sometimes referred to as the product) is transported and advanced for further processing.

If a particularly low-density product is desired, the additional treatment performed by the second air chamber 8 can be dispensed with. The product density can also be controlled already during the mat formation process by the flow velocity of the air flow A traveling through the air chamber 6, said flow velocity being the force that the fibers penetrate through the mat structure. Is forming.

FIG. 4 schematically illustrates one possible arrangement for air flow in the present invention. The air flow is circulated so that the mat-forming air flow or flow A reaching the collection chamber 10 is directed into the first air passage 3 by a fan 12. During this time, the air flow is such that the temperature of the first air flow A1 discharged from the air passage 3 through the slit orifice 3a becomes lower than the temperature at which the binder material can be activated. Have time to cool. Thus, this air flow A1 only serves to release the particles from the supply roll 2, but it can also be used for preheating, whereby the air flow A2 leaving the air passage 4 is brought to a particularly high temperature. do not have to. The air flow A2 is sent from the heater 7 into the second air passage 4 by the fan 13. The air passage 4 has an air passage 9 connected to the second air chamber 8.
A part of the heated air flow A1 sent by the fan by this air passage is withdrawn as an air flow B for the next treatment of the mat. This also ensures that in the next treatment the temperature of the air flow B is sufficiently high, and that the air passage is sourced from the air passage 4 which only contains heated air flow. Therefore, its temperature is actually higher than that of the air chamber 6. However, since the material is surrounded by the mat support material contained within the particles and is not exposed to this air as much,
This air does not harm the material, while the air flow rate per unit area is kept very low due to the size of the chamber 8.

The air flow B received in the second collection chamber 15 on the other side of the forming platform 1 circulates and returns to the heater 7 by means of an air passage 18. Chamber 8 also receives air carried from chamber 6 with the mat. This air is a collection room
It passes through 15 and merges with the exhaust flowing to the heater 7. A portion of the air traveling in the first air passage 3 is forced out through the duct 17 in order to maintain the air balance. this is,
This is supplemented by sending not only circulating air but also supplemental air from the outside to the heater 7. It is possible to circulate the air from the duct 17 to the heater 7, but the extent of this circulation is determined by the impurities that accumulate in the air during the mat manufacturing process.

Further, FIG. 4 is a system diagram showing a conventional measurement and control device for setting the temperature of the air flow as desired.

All possible product shapes, from flexible mats to rigid plates, can be envisaged for products made according to the invention.

In this method, any particles that are activated at a temperature in which they become adherent to each other can be utilized as particles that form the support structure of the mat. Such particles can be molten materials such as molten minerals (“rock fibers” or rockwool fibers or glass fibers) or fibers made from thermoplastic materials. The density of the mat is influenced by the choice of fiber grade and ratio, but other types of particles can be used as long as they are particles capable of forming a mat by air flow.

An example of a heat-activatable binder material that can be used is a thermoplastic material such as a thermoplastic polymer, such as polypropylene or polyester. When the thermoplastic material softens under the influence of heat, it is activated into an adhesive state. It is also possible to use a conjugate material that comprises a polymer that softens on the surface of the particles at lower temperatures. Particles, such as conjugated fibers, can be used as a binder material to bind other particles forming the support, or as the particles forming the support themselves, and are active at higher temperatures. The material to be converted serves as the material forming the support of the mat.

The temperature of the air flow A flowing in the air chamber 6 can be set according to the activation temperature of the binder material, which is the temperature at which the binder material softens to an adhesive or tacky state. In the case of the thermoplastic polymer material used, it is in the range of 100 to 200 ° C. The activation temperature of the material forming the support is higher than this temperature. Therefore, a thermoplastic material that melts at a higher temperature can be used as the support material, and a thermoplastic material that melts at a lower temperature can be used as the binder material. The mat structure can also be controlled by selecting the ratio of thermoplastic binding material to support material. The raw material underlying the structure of the product consists of the support material, which preferably constitutes the majority of the total mass of the mat.

Weight-made mat, per unit area 40 g / m ² to 30
Be in the range of 00g / m ^2, density of 18kg / m ³ ~400g /
It can be in the range of m ³ .

The obtained product can be used for various purposes such as heat insulating materials, filters, various interior materials for buildings and vehicles, depending on the type of particles, the thickness and rigidity of the mat. In the form of a semi-finished product that can be pressure-molded again by heat,
It can also be used for various purposes. The resulting product can also be post-treated to enhance its properties.

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B27N 3/00-3/28

Claims (10)

(57) [Claims] 1. An air flow (A) is used to form a mat from particles on an advancing forming platform (1) in which the particles are thermally activated binder. A method for producing a mat which is adhered to each other by means of a binder, which carries the particles onto a forming platform (1) by setting the temperature of the air flow (A) high enough. Already activated in an air flow (A), the particles consisting of a material that is activated at a temperature higher than the binder and higher than the air flow (A), The binder is used together with the particles in the air flow (A).
A method for manufacturing a mat, characterized in that it is supplied to a forming platform (1) according to. 2. A method for producing a mat according to claim 1, characterized in that the binder is on the surface of the particles which are directed onto the forming platform (1). 3. The mat according to claim 2, wherein the particles are fibrous, and a binder is present on the surface of the particles, and the particles and the binder form a conjugate fiber. Method for manufacturing. 4. The mat according to claim 1, wherein the binder is particulate, and the particles adhered to each other by the binder and the particulate binder are separate. the method of. 5. The method for producing a mat according to claim 4, wherein both the particles and the particulate binder are fibrous. 6. The air flow (A) is a mixture of a first air flow (A1) and a higher temperature second air flow (A2). 2. The temperature of is increased to a temperature at which the binder is activated.
A method for producing the mat according to one of the items 1 to 5. 7. After the mat is formed on the forming platform (1) by the air flow (A), the mat is supported on the side opposite to the flowing direction of the air flow (A), Process for producing a mat according to one of claims 1 to 6, characterized in that a stream (B) of a gaseous medium is passed through the mat. 8. A method for producing a mat according to claim 7, characterized in that the flow (B) of the gaseous medium exerts pressure on the mat to increase its density. 9. A first air flow (A1) and a hotter second air flow (A2) are supplied through their own air passages (3,4), said air flow (A) After forming the mat and passing through the forming platform (1), a part of the air flow (A) passing through the forming platform (1) is an air passage of the first air flow (A1). 9. For producing a mat according to one of claims 6-8, characterized in that (3) is fed and circulated for preheating of its first air flow (A1). Method. 10. The part of the second air flow (A2) traveling through the air passage (4) forms at least part of the flow (B) of the gaseous medium through the mat. Method for producing a mat according to one of claims 7-9.