JPH02219615A - Production of thermally moldable composite material - Google Patents

Abstract

PURPOSE:To continuously produce the thermally moldable composite material which is large in porosity with less irregularity in thickness by forcibly expanding the mat-shaped material being in such a state that thermoplastic resin has been melted, by a spreader with magnets utilized therefor. CONSTITUTION:A mat-shaped material being in such a state a binder has been melted is compressed by a compressor 3 at the temp. higher than the m.p. of thermoplastic resin. The intervals of fiber of the mat-shaped material are sufficiently impregnated with the binder by this compression. Then this mat- shaped material is transferred until spreader 4 in accordance with movement of the transfer belts 1a, 1b. Therein the transfer belt 1a of the upside is attracted to a magnet 6a of the upside and therefore moved while it is guided by a guiding roll 4a of the upside. The transfer belt of the underside is attracted to a magnet 1b of the underside and therefore moved while it is guided by a guiding roll 4b of the underside. Therefore the interval between both transfer belts 1a, 1b is gradually spread in accordance with the movement of belts 1a, 1b. As a result, the thickness of mat-shaped material stuck to the inner faces of both transfer belts 1a, 1b is gradually increased.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a thermoformable composite material mainly composed of inorganic fibers, which are bonded together with a binder whose main component is a thermoplastic resin. The present invention relates to a method for producing a thermoformable composite material that can continuously obtain a thermoformable composite material.

(Prior art) Conventionally, in order to produce a thermoformable composite material, a sheet-like material made of reinforcing fibers having high elasticity and a thermoplastic plastic material is heated to melt the plastic material and form the reinforcing fibers. A method has been proposed in which a sheet material is expanded by removing stress and then compression molded (
(Japanese Unexamined Patent Publication No. 62-161529).

According to this method, the thickness of the sheet-like article can be increased using the elastic restoring force of the reinforcing fibers, so that the composite material can be molded with good moldability during compression molding.

(Problem to be Solved by the Invention) However, in the conventional method, in order to restore the thickness of the sheet-like product, it is done only by the restoring force of the reinforcing fibers, so depending on the degree of heat applied, etc. Another drawback is that the thickness varies depending on the product, and furthermore, it has not been possible to further increase the porosity of the sheet material.

Therefore, if an attempt was made to use the obtained sheet-like material as it is, for example, as a sound absorbing member or a heat insulating member, the properties thereof would be insufficient and it would not be possible to further reduce the weight.

The present invention has been made in view of the above-mentioned drawbacks, and it is possible to control the thickness, reduce thickness variations, and continuously obtain a thermoformable composite material with a higher porosity. The purpose of the present invention is to provide a method for manufacturing a thermoformable composite material that can be manufactured using a thermoformable composite material.

(Means for Solving the Problems) The method for producing a thermoformable composite material of the present invention is a thermoplastic resin that is made of a member that has the property of adhering in a molten state and peeling off in a solid state, and that can be attracted to a magnet. A step of supplying a mat-like material having a binder mainly composed of a thermoplastic resin and inorganic fibers between the pair of conveyor belts and heating it to a temperature equal to or higher than the melting point of the thermoplastic resin; A step of compressing the mat-like material by compressing the belt from both sides with a compression device, and a pair of magnets each disposed on the outside of both transfer belts at a position rearward in the transfer direction of the transfer belt from the compression device. By adsorbing each transfer belt with
increasing the thickness of the compressed mat by widening the distance between the pair of transfer belts; cooling the transfer belt to peel the mat from the inner surfaces of both transfer belts;
, thereby achieving the above objective.

[Creation of mat-like material]

The mat-like material has a binder whose main component is a thermoplastic resin and inorganic fibers.

Examples of the inorganic fibers used in the present invention include one or more of glass fibers, rock wool, ceramic fibers, carbon fibers, etc. Among them, glass fibers are preferred. The inorganic fiber is preferably one obtained by defibrating an inorganic fiber strand in which a large number of filaments are bundled. The length of the inorganic fibers is preferably 5 to 20 G+am, more preferably 10 to 100 G+am, from the viewpoint of ease of forming a mat-like material. In particular, length 50
It is preferable that 70% by weight of particles having a diameter of mm or more is contained. In addition, as the thickness becomes thinner, the mechanical strength decreases, and as it becomes thicker, the weight ≦ and the bulk density increases, so 5 to 3
The heel range is preferably 0 μm, more preferably 7 to 20 μm.
It is.

The binding material that partially binds the inorganic fibers is polyethylene,
The main component is a thermoplastic resin such as polypropylene, saturated polyester, polyamide, polystyrene, polyvinyl butyral, or polyurethane. The form of this binding material can be any form such as fiber, powder, film, etc.
Each of them is used in a suitable form depending on the method for manufacturing the thermoformable composite material.

When the binder is used as fiber, it is mixed with inorganic fibers to form a mat-like material.

For example, feeding inorganic fiber strands to a card machine,
The strands are defibrated into filaments and mixed with thermoplastic resin fibers to produce a mat-like product. Regarding the dimensions of the thermoplastic resin fiber, from the viewpoint of forming a mat-like object, the length is preferably 5 to 200 weight, more preferably 20 to 100 mm, and the thickness is preferably 3 to 50 μm, more preferably It is 20 to 40 μm.

When the binder is used as a powder, it can be used together with inorganic fibers to form a mat like a fibrous binder, or it can be used with air after forming a mat with the inorganic fibers. A mat-like material is formed by being press-fitted into a mat by spraying or the like and held therein. Alternatively, after a mat is formed from inorganic fibers or inorganic fibers and thermoplastic resin fibers, a dispersion or emulsion of thermoplastic resin powder may be sprinkled onto the mat and dried. The diameter of the thermoplastic resin powder is between 50 and 100 mm when it is added in powdered form.
Metsushi is preferred. Furthermore, when the powder is added in a dispersed state or as an emulsion, the diameter may be smaller.

When the binder is used as a film, a mat-like material is formed by laminating it on a mat made mainly of inorganic fibers.

Binder materials having different forms as described above may be used in combination. For example, a mat is formed from inorganic fibers alone or from the inorganic fibers and a fibrous and/or powdered thermoplastic resin binder,
A mat-like material may be formed by laminating one or more thermoplastic resin films on at least one surface of the mat. When using a mixture of different types of binders, it is preferable that the melting temperatures of these binders are as similar as possible.

Regarding the ratio of the inorganic fibers to the binder, if the amount of the binder decreases, the number of bonded parts decreases and the mechanical strength of the thermoformable composite material decreases, and conversely, if the amount increases, the porosity decreases.
When using a thermoplastic resin film as a binder, the weight ratio is preferably 1/10 to 2/1 of the total weight of the mat-like material, and when using thermoplastic resin fibers or powder as a binder, the weight ratio is preferably 1/10 to 2/1 of the total weight of the mat-like material. ~4/1 is preferred.

The density of the mat-like material obtained in this way increases as the density increases;
It is preferably 0.01 to 02 g/c+*3, more preferably 0.03 to 0.07 g/c+m''. The overall porosity is preferably 70 to 98%. Also, in order to increase the strength, needle Punching may be performed, and preferably needle punching is performed at 1 to 50 locations per 1 cm.

[Manufacture of aged formable composite material]

Next, a method for manufacturing the thermoformable composite material of the present invention will be explained.

The present invention can be carried out using the apparatus shown in FIG.

This device includes a transfer device 1 having a pair of upper and lower endless belt-shaped transfer belts 1aSlb, a heating device 2, a compression device 3, a transfer belt expansion device 4, a cooling device 5,
It is equipped with

Each of the transfer belts la, it) is wound around a drive roll lO and a plurality of guide rolls 11, 11, . . . and is configured to be rotated by the drive of the drive roll lO. Each of the transfer belts la, lb is provided with substantially linear transfer portions 12a, 12b facing each other, and the pair of transfer belts la, ib have transfer portions 12aS12.
A mat-like material supplying section 13 is formed between b. The transfer parts 12a and 12b are moved in the same direction (
It is designed to move in the direction of the arrow.

Transfer bells) la and lb are made of a material to which molten thermoplastic resin adheres, solidified thermoplastic resin does not adhere, and which attracts magnets, such as belts mainly made of iron or nickel. It is possible to use a base material whose outer surface is coated with a release agent such as Teflon or silicone, or a belt base material whose outer surface is coated with a thin aluminum plate.

In order to heat the thermoplastic resin of the mat-like material supplied into the transfer device 1, the heating device 2 has a heating temperature set at a temperature higher than or near the melting temperature of the thermoplastic resin used for the mat-like material. has been done. Preferably, the heating device 2 is one that heats the entire body using hot air from a dryer, or one that uses radiation heating using a far-infrared heater, an infrared heater, or the like.

The compression device 3 has an upper press roll 3a and a lower press roll 3b arranged above and below with a small gap in between. The upper and lower press rolls 3as and 3b each have a large number of rolls, and the gap between the upper roll 3a and the lower roll 3b is such that the mat-like material passing between the upper and lower rolls 3a and 3b has a large number of rolls.
It is set so that a pressure of 12 g/cI acts on 0. The pressing rolls 3a, 3b may be formed by heating rolls, and the mat-like material may be heated and compressed at the same time. In addition, as the compression device 3, it may replace with a press roll and may be comprised with an endless track device.

A transfer belt expanding device 4 is disposed at a rear position of the compression device 3 in the transfer direction. The expanding device 4 has an upper guide roll 4a, a lower guide roll 4b, and magnets 6as 6b, which are composed of a plurality of rolls.

The gap between the upper guide roll 4a and the lower guide roll 4b is set larger than the gap between the upper and lower compression rolls 3a, 3b, so that the pressure gap between the pair of transfer bells 3a, 3b is reduced. From the guide roll 4a.

It gradually widens as it moves toward the 4b side.

The distance between the upper and lower guide rolls 4a, 4b is set to approximately match the desired thickness of the thermoformable composite material. Furthermore, among the guide rolls 4as and 4b, the first rolls 4a' and 4b' are adjustment rolls that can be adjusted vertically, and by changing the interval between these adjustment rolls 4a'' and 4b°, thermoforming can be performed. The thickness of the composite material can be gradually increased.

Although electromagnets and permanent magnets can be used as the magnets 6a and 6b, electromagnets are particularly preferred because their attraction force can be adjusted. Further, since the magnets are used at high temperatures, it is preferable to wind a cooling coil around the magnets 6a and 6b to cool them.

A cooling device 5 is disposed at a rear position in the transfer direction of the transfer bells (Ia, lb) of the expanding device 4. The cooling device 5 is disposed on the outside of each transfer belt (laSlb), and is capable of cooling each transfer belt (la, lb). The cooling device 5 may be either an air-cooled type or a water-cooled type.

Next, a method for manufacturing a thermoformable composite material of the present invention will be explained using the apparatus having the above configuration.

The mat-like material obtained above is supplied to the supply section 13 between the pair of transfer bells (la) and Lb shown in FIG.

The mat-like material is heated by the heating device 2 while the mat-like material is being transferred to the compression device 3 as the two transfer belts las ib move. The heating temperature of the heating device 2 is preferably a temperature higher than that at which all the thermoplastic resin of the mat-like material melts, for example, 10 to 70°C higher than the melting temperature of the thermoplastic resin.
Preferably, the mixture is heated at a high temperature for 1 to 10 minutes. Note that the mat-like material may be preheated before being supplied to the transfer device 1.

The mat-like material in which the binder is in a molten state is compressed by the compression device 3 at a temperature higher than the melting temperature of the thermoplastic resin. By this compression, the binder is sufficiently impregnated between the fibers of the mat-like material. The compressive strength here is 0.
5 to 30 kg/cm2 is preferable.

If the compressive strength is too lower than the above range, resin impregnation will be insufficient, and if the pressure is too high than the above range, the pressure may damage the inorganic fibers. In addition, if the thermoplastic resin is cooled and solidified during compression, the thickness of the mat-like material will not recover in the next step, so the pressure rolls 3a, 3
Preferably, b is also heated.

Next, this mat-like material is transferred to the spreading device 4 along with the movement of the transfer belt LAS lb. Here, since the upper transfer belt (la) is attracted to the upper magnet 6a, it moves while being guided by the upper guide roll 4a, and the lower transfer belt lb is attracted to the lower magnet 6b. Therefore, it moves while being guided by the lower guide roll 4b. Therefore, as the transfer belt las lb moves, both transfer belts 1a
, Lb gradually widens, and as a result, the thickness of the mat-like material adhered to the inner surfaces of the side transfer belts la, lb gradually increases.

Next, each transfer bell (la, lb) and the mat-like material are cooled by the cooling device 5, and the binding material of the mat-like material is solidified and no longer adheres to the transfer belts la, Lb, and the solidified mat-like material is removed from the transfer belt. ) la, lb, and the thermoformable composite material is thus removed.

The obtained thermoformable composite material has inorganic fibers bound together with a binder at their intersections, has many voids throughout the mat, and has internal voids on the surface of the mat. A large number of pores are formed that communicate with the voids in the pores. This thermoformable composite material has good heat formability, and can be easily molded into a desired shape by simple processing means such as pressing, to obtain a molded product with a curvature that follows the curvature of the mold. The thickness of the thermoformable composite material may be determined as appropriate depending on the application, but it is generally 4 to 200 m1, and particularly 4 to 12 m when used as a ceiling material for automobiles.
is preferred.

(Example) Hereinafter, the present invention will be explained in detail based on examples.

A thermoformable composite material was produced from the mat-like material shown below using the apparatus shown in FIG. The conditions for the apparatus were as follows.

Mat-like material glass fiber (diameter 11 μm, length 50 mm)
) and polypropylene fiber (diameter 18 μm, length 50 mm
, melting point 165° C.) were defibrated and mixed at a weight ratio of 4:1, and needle punched (20 locations/c+n2) to create a mat with a thickness of 7 m1As and a width of 1400 mm. The density of this mat was 0.5 g/am3, of which the density of glass fiber was 0.4 g/cm3, and the density of polypropylene fiber was O,Ig/c+*'. Next, polyethylene films (melting point: 135°C) each having a thickness of 110 μm and a width of 1450 mm were laminated on both sides of this mat to obtain a mat-like product.

A transfer belt was used in which an aluminum plate with a width of 1500 am and a thickness of 1 mm was riveted to the outer surface of an iron plate with a thickness of 1 mm.

The heating device was a hot air oven heated to 220° C., and it took 1.5 minutes to reach the compression device. The temperature of the mat-like material had reached 200°C.

The compression rolls on the upper and lower sides of the compression device consist of 5 rolls.
The diameter of each roll is 30011111% Roll axis 100m
＋＊.

The roll surface is 1700mm, and the clearance between the upper and lower compression rolls is 45+*m. Therefore, since the thickness of the two transfer belts is 4cm, the thickness of the mat-like material is 0.5cm.
+nl is compressed.

Expanding device: An iron device with a magnetic force of 0.5 g/cm2 was used. The spacing between the adjustment rolls was set to 7 mm.

Cooling device: Air cooling (outside temperature 25°C).

In the above device, the thermoformable composite material delaminated from the surface of the transfer belt when the transfer belt reversed.

The width of the thermoformable composite material obtained was 1400 mm,
The length was cut into pieces of 1800 m. The thickness of the thermoformable composite material is 7 tals, the density is Q, Ig/am3, and the porosity is 9
It was 3%. Also, when I measured the variation in thickness with a caliper, the measured value at 20 points was 6.5 to 7 against the setting of 7■.
．． All points were eaten within a 1mm radius.

A mat-like material similar to that of the Arashi Viper Plate Example was supplied to the press, and 220
After heating to and compressing the mixture, it was cooled to 25°C using a cooling roll to obtain a composite material having a thickness of approximately 0.4+a+a. A cooling roll was provided at the location of the cooling device of the example, and the mat-like material was cooled while being compressed. The pressure of the cooling roll was 31 g/am.

Next, when this material was heated to 200° C. for press molding, a thermoformable composite material with increased thickness was obtained. When the thickness of the thermoformable composite material was measured at 20 points, the maximum thickness was 5.3 mm and the minimum thickness was 3.1 mm.
The average thickness at point 0 was 4.4 mrx. In addition, the density of the thermoformable composite material is O, 16g70m3, and the porosity is 89
%Met.

As described above, it was confirmed that the thermoformable composite material obtained by the present invention has a constant product thickness with little variation.

(Effects of the Invention) As described above, the present invention forcibly expands a mat-like material in a molten state of thermoplastic resin using an expanding device using a magnet. Since the material can be obtained and its thickness can be controlled by the expanding device, thermoformable composite materials with less variation in thickness can be continuously obtained.

The resulting thermoformable composite material has sufficient strength and heat resistance because the inorganic fibers are partially bound by a thermoplastic resin binder, and a higher porosity than conventional materials has been achieved. It is also possible to achieve further weight reduction.

4. Of, M■ FIG. 1 is a schematic diagram of the apparatus used in the present invention.

1...transfer device, las lb...transfer belt, 2
... Heating device, 3... Compression device, 4... Expansion device, 5... Cooling device, 6a, 6b... Magnet.

that's all

Claims (1)

[Claims] 1. A thermoplastic resin is mainly used between a pair of transfer belts formed of a member that has the property of adhering to a thermoplastic resin in a molten state and peeling off in a solid state, and can be attracted to a magnet. A step of supplying a mat-like material having a binder and inorganic fiber as components and heating it to a temperature higher than the melting point of the thermoplastic resin, and a step of heating both transfer belts at a temperature higher than the melting point of the thermoplastic resin. A process of compressing the mat-like material by compressing it from both outer surfaces with a compression device, and transferring it with a pair of magnets respectively disposed on the outside of both transfer belts at a position rearward in the transfer direction of the transfer belt from the compression device. A step of increasing the thickness of the compressed mat-like material by widening the distance between the pair of transfer belts by adsorbing the belts, and a step of cooling the transfer belts and peeling off the mat-like material from the inner surfaces of both transfer belts. A method for producing a thermoformable composite material comprising: