JPH02219616A - 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 changing the interval of the transfer belts and forcibly expanding a mat-shaped material being in such a state that thermoplastic resin has been melted. CONSTITUTION:A mat-shaped material being in such a state that a thermoplastic resin binder has been melted is compressed by a compressor 3 at the temp. higher than m.p. of thermoplastic resin. The intervals of fiber of the mat-shaped material are sufficiently impregnated with the binder by this compression. Further when thermoplastic resin is cooled and solidified in the case of compressing the mat-shaped material, the thickness thereof is unrecovered in the ensuing stage. Therefore the pressing rolls 3a, 3b are preferably heated. Then this mat- shaped material is transferred to a spreading part 14 by movement of the transfer belts 1a, 1b. Therein the upper and lower faces of the mat-shaped material are stuck to the inner faces of the transfer belts 1a, 1b and the interval between both transfer belts 1a, 1b is gradually spread. Therefore the thickness of the mat-shaped material is gradually increased in accordance with the movement of the transfer belts 1a, 1b.

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 a-fibers having high elasticity and a thermoplastic plastic material is heated, thereby melting the plastic material and forming the above-mentioned reinforced material. A method has been proposed in which a sheet material is expanded by removing stress from the fibers 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 was made in view of the above-mentioned drawbacks, and an object of the present invention is to continuously obtain a thermoformable composite material that can control the thickness, reduce variations in thickness, and has a higher porosity. The purpose of the present invention is to provide a method for manufacturing a thermoformable composite material that can be used.

(Means for Solving the Problems) The method for producing a thermoformable composite material of the present invention provides a method for producing a thermoformable composite material between a pair of transfer belts formed of a member having a property of thermoplastic resin adhering in a molten state and peeling off in a solid state. a step of supplying a mat-like material having a binder mainly composed of a thermoplastic resin and inorganic fibers 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 both transfer belts from both outer surfaces thereof, a step of increasing the thickness of the compressed mat-like material by gradually widening the interval between the pair of transfer belts, cooling the belt to peel the mat-like material from the inner surfaces of both transfer belts, thereby achieving the above object.

[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 200+*m, more preferably 10 to 10t)sm in terms of ease of forming a mat-like material. In particular, the length is 50mm
It is preferable that 70% by weight of the above is contained. In addition, as the thickness becomes thinner, the mechanical strength decreases, and as it becomes thicker, the bulk density increases, so 5 to 30μ
A range of m is preferred, more preferably 7 to 20 microns.

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 material, the length is preferably 5 to 200 m1, more preferably 20 to 100 mm, and the thickness is preferably 3 to 50 m, more preferably 20 m1. ~40μl.

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.
Metushini is preferred. Further, 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 one side of the mat. When using a mixture of different types of binders, The melting temperatures of these binders are preferably similar.

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 if the ratio increases, the porosity decreases.
When using a thermoplastic resin film as a binder, the total weight ratio of 74 pieces (D 1 /10 to 2/1
is preferable, and when using thermoplastic resin fibers or powder as the binder, 115 to 4/1 is preferable.

The higher the density of the mat-like material obtained in this way, the heavier it becomes, and the lower the density, the lower the mechanical strength.
0.01-0.2 g/c 3 is preferable, more preferably 0.03-0.07 g/c+s''. The overall porosity is preferably 70-98%. Also, in order to increase the strength (Needle punching is preferably performed at 1 to 50 locations per ICI2.

[Manufacture of aged formable composite material]

Next, a method for producing the aged formable composite material of the present invention will be explained.

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

This device is an endless belt-shaped transfer bell arranged in pairs (upper and lower).
The transfer device 1 includes a transfer device 1 having 1a and 1b, a heating device 2 disposed within the transfer device 1, a compression device 3, and a cooling device 5.

Each of the above transfer bells) la and lb are drive rolls 10. Turn rolls 15a, 15b and a plurality of guide rolls 11.
11..., and is configured to rotate and move by driving the drive roll IO. Each transfer bell) la, lb has substantially linear transfer portions 12a, 1
2b are provided to face each other, and a pair of transfer belts 1as
A mat-like material supply section 13 is formed between the transfer sections 12a and 12b. Then, °this transfer section 12a
, 12b are adapted to move in the same direction (arrow A direction).

The transfer bell) laSlb is made of a material that adheres to molten thermoplastic resin and does not adhere to solidified thermoplastic resin, such as Teflon belts and heat-resistant fibers such as glass fiber, carbon fiber, and aramid fiber. A Teflon-coated material, an aluminum plate, a steel plate coated with Teflon, etc. can be used.

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 is comprised of an upper press roll 3a and a lower press roll 3b which are disposed vertically 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 and lower press rolls 3a and 3b is such that the mat-like material passing between the upper and lower press rolls 3a and 3b is 0.5 to 30 kg/c+a. The pressure rolls 3a and 3b may be formed by M rolls, and the mat-like material may be heated and compressed at the same time.

At the rear position of the compression device 3 in the transfer direction, both transfer bells (1a, 1b) are provided with widening portions 14 that are inclined so as to widen the interval in the transfer direction.

That is, the turn roll lsa around which the upper transfer belt 1a is wound is disposed above the extension line of the upper pressure roll 3a, and the turn roll 15b around which the lower transfer belt lb is wound is placed above the lower pressure roll 3a. A pair of upper and lower turn rolls 15 are arranged below the extension line of the roll 3b.
The distance between a and 15b is the upper and lower press rolls 3a.

Therefore, both transfer belts la and ib are constructed so that the distance between them increases at a predetermined angle from the pressure rolls 3as and 3b to the turn rolls 15a and 15b. In addition, as the compression device 3, it may replace with a press roll and may be comprised with an endless track device.

A cooling device 5.5 is arranged at a rear position of the expansion part 14 in the transport direction. A cooling device 5.5 is connected to each transfer belt 1aSl.
b, and each transfer belt la
, Ib can be cooled.

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 Ib 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 bells (la and lb) 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, and for example, heating is preferably performed for 1 to 10 minutes at a temperature 10 to 70° C. higher than the melting temperature of the thermoplastic resin. Note that the mat-like material may be preheated before being supplied to the transfer device 1.

In this manner, the mat-like material in which the thermoplastic resin binder is in a molten state is compressed by the compression device 3 at a temperature equal to or 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 preferably 0.5 to 3 oxg/c12. 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 break the inorganic fibers. Further, if the thermoplastic resin is cooled and solidified during compression, the thickness of the mat-like material will not be restored in the next step, so it is preferable that the pressing rolls 3a and 3b are also heated.

Next, this mat-like material is transferred to the expanded portion 14 by the movement of the transfer bells (la, lb). Here, the upper and lower surfaces of the mat-like material are adhered to the inner surface of the transfer belt 1aSlb,
Since the distance between the two transfer belts la and lb is gradually widening, the thickness of the mat-like material gradually increases as the transfer belt Ias Ib moves.

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 bell) la, lb, and the solidified mat-like material is transferred. #IM from bell) la, lb, and thus the thermoformable composite material is taken out.

Note that a peeling member may be provided that slides into contact with the inner surface of each transfer belt 1aSlb at a position near the turn roll 15a11Sb.

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 having a curvature that closely follows the curvature of the mold. Can be done. The thickness of the thermoformable composite material may be determined as appropriate depending on the application, but it is generally 4 to 200 m thick, and particularly when used as an automobile ceiling material, it is 4 to 12 + *
m 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. In this apparatus, the conditions were as follows.

Mat-like material Ni glass fiber (diameter 11 μm 1 length SOam
) and polypropylene fiber (diameter 18 μm 1 length 5011
11% melting point 165℃) was defibrated and mixed at a weight ratio of 4:1, and needle punched (20 locations/cI++2) to form a mat with a thickness of 7cm, width of 1400mm, and density of 0.5g/c-. Created. Next, apply a thickness of 11 mm on both sides of this mat.
A mat-like material was obtained by laminating polyethylene films (melting point: 135° C.) each having a width of 0 μm and a width of 1450 t+s.

Transfer belt: An iron belt base material with a width of 1000 mm and a thickness of 1 m+s coated with Teflon was used.

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

Compression device: The upper and lower press rolls each consist of 5 rolls, each roll has a diameter of 30G+ub, roll shaft 10 (
lsms The roll temperature was 200°C, and the clearance between the upper and lower press rolls was set to 2.5 mm. Therefore, since each of the two transfer belts has a thickness of lam, the mat-like material is compressed by 0.5 mm4.

The distance between the pair of pressure rolls on the expanded portion of the transfer belt is set to 2.
5, the distance between the pair of turn rolls is 101 times, and the distance from the pressure roll to the turn roll is 8.3 m.
And so.

? The clearance between the pair of transfer belts in the six cooling devices is 8m.
Cooling (air cooling) was started when the thickness of the mat-like material reached +m (the thickness of the mat-like material was 6 mm), and air cooling was continued until the turn roll was reached. The length of this cooling section was 3 m.

In the above device, the thermoformable composite material peeled off from the surface of the transfer belt when the transfer belt reversed. The width of the thermoformable composite material obtained is 1400 mm, and the length is 1
It was cut into 800+m weight. The thickness of the thermoformable composite material is 7
(2) The density was 0°Ig/am3, and the porosity was 93%. In addition, when measuring the variation in thickness with a caliper, it was found to be 71I.
For the setting of 11, the measurement value of 20 points is 6.5 to 7.1 m
All points were in the range of m.

A mat-like material similar to that of the salt spatula and the example was fed to a press, and 220
After heating to ℃ and compressing, it is cooled to 25℃ to a thickness of about 0.
A 4m+m composite material was obtained. Cooling was performed in the apparatus of the example while compressing the transfer belt without widening the belt interval. The pressure during cooling was 3 Kg/cm.

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 5.311% by weight and the minimum thickness was 3.1 mm, and the average thickness of the 20 measurement points was 4.4 mm. In addition, the density of the thermoformable composite material is 0.16 g/cm3, 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 the mat-like material in the molten state of thermoplastic resin by changing the interval between the transfer belts. Since the material can be obtained and its thickness can be regulated by the inclination of the transfer belt, it is possible to continuously obtain a thermoformable composite material with less variation in thickness.

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 day of the day 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, 14... Expansion part of transfer belt, 5... Cooling device.

that's all

Claims (1)

[Claims] 1. A binder mainly composed of a thermoplastic resin and a thermoplastic resin between a pair of transfer belts formed of a member having the property of adhering in a molten state and peeling off in a solid state. supplying a mat-like material having inorganic fibers and heating it to a temperature equal to or higher than the melting point of the thermoplastic resin; and compressing both transfer belts from both outer surfaces thereof at a temperature equal to or higher than the melting point of the thermoplastic resin. a step of compressing the mat-like material by gradually widening the interval between the pair of transfer belts to increase the thickness of the compressed mat-like material; and a step of cooling the transfer belt and compressing the mat-like material onto the inner surfaces of both transfer belts. A method for producing a thermoformable composite material, comprising: exfoliating the material from the material.