JPH02292015A - Manufacture of foam rubber molding - Google Patents

Abstract

PURPOSE:To manufacture a foam rubber molding capable of setting excellent dimensional accuracy of a molding and having less control loss by measuring the dimension of an extrusion molding extruded from an extruder, and increasing or decreasing the speed of a screw of the extruder on the basis of the increase of decrease of the dimension. CONSTITUTION:The tape base material 2 of a rubber material is held in a accommodation container 3, and then supplied into a hopper 4 on the upper part of an extruder 1. In the extruder 1, a cylinder 6 having a screw 5 inside is disposed, which extrudes a rubber material from the hopper 4. In the tip end of the extruder 1, a die 7 is attached thereon, which forms an extruded molding P extruded by the screw 5. Ahead of the extruder 1, an optical dimension measuring unit 8 is arranged for irradiating light on the extruded molding P and measuring successively the dimension thereof. And, ahead of the measuring unit 8, a microwave heating unit 10 having a conveyer 9 inside is placed, and the extruded molding P is heated, and thus cured, while moving on the conveyor 9. Furthermore, a hot air furnace 12 having a conveyor 11 is arranged thereon, and the extruded molding P is cured while moving thereon, thereby obtaining a cured molding Q.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the manufacture of foamed rubber molded products used as automobile seal parts such as weather strips, which are extruded by an extrusion method and then heated and vulcanized. It is about the method.

[Conventional technology]

Conventionally, elongated molded products of sponge rubber as foamed rubber have been extruded into a predetermined shape using an extruder, and then heated and heated using microwaves (UHF) or hot air while being conveyed by a belt.
It is vulcanized and molded by keeping it warm. in this case,
The dimensions of the vulcanized product are adjusted by measuring the dimensions of the vulcanized product, and when the dimensions deviate from the predetermined dimensions, the extruder screw rotation speed is adjusted accordingly. There is.

[Problem to be solved by the invention] However, the rubber material (kneaded dough) supplied to the extruder is
Because it is produced in batches and supplied to the extruder, the composition of the rubber material changes slightly each time the batch changes, resulting in variations in the dimensions of the extruded product extruded from the extruder and, by extension, the dimensions of the vulcanized product. However, since the process of heating and vulcanizing the extruded product is long, the method of adjusting the rotation speed of the extruder screw based on the variation in the dimensions of the vulcanized product cannot accommodate the variation due to batches of rubber materials. There was a problem in that the dimensions of the vulcanized product could not be set with high accuracy and control loss occurred.

An object of the present invention is to provide a method for manufacturing a foamed rubber molded product that allows the dimensions of a vulcanized molded product to be set with high precision even if the rubber material changes from batch to batch, and that reduces control loss.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a foamed rubber molded product in which a rubber material is extruded from an extruder into a predetermined shape by rotating a screw, and then heated and vulcanized. In the manufacturing method, the dimensions of the extruded product extruded in a predetermined shape from the extruder are measured, and based on the increase or decrease in the dimensions, the rotation speed of the screw of the extruder is similarly increased or decreased. We have adopted the method of letting

[Function] By adopting the above means, when the viscosity of the rubber material supplied to the extruder is low, the dimensions of the extruded product extruded from the extruder become small, and conversely, when the viscosity of the rubber material is high, the extrusion molding becomes smaller. As the dimensions of the product increase, there is a positive correlation between the viscosity of the rubber material and the dimensions of the extruded product. In addition, if the viscosity of the rubber material is low, it will easily foam and the dimensions of the vulcanized molded product will increase, whereas if the viscosity of the rubber material is high, it will be difficult to foam and the dimensions of the vulcanized molded product will become small. There is a negative correlation between and vulcanized molded products.

On the other hand, when the screw rotation speed is increased, the dimensions of the vulcanized molded product become thicker, and conversely, when the screw rotation speed is decreased, the dimensions of the vulcanized molded product become smaller. There is a positive correlation with the dimensions of the product.

In this way, there is a certain correlation between the dimensions of the extruded product, the viscosity of the rubber material, the rotation speed of the screw, and the dimensions of the vulcanized product, so the average value of the dimensions of the extruded product is measured, By changing the rotational speed of the screw based on the amount of change, even if the rubber material changes from batch to batch, the dimensions of the vulcanized product can be set with high precision by immediately responding to it, while reducing control loss. be able to.

〔Example〕

Embodiments embodying the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, at the rear of the extruder 1 (left side in FIG. 1), a tape base material 2 made of ethylene-propylene-diene copolymer rubber (EPDM) as a rubber material is placed in a storage container 3. It is stored and supplied from the upper part to the omper 4 above the extruder 1. Inside the extruder 1, a cylinder 6 having a screw 5 inside is disposed, and a hopper
The rubber material from 4 is extruded. A mold 7 is attached to the tip of the extruder 1, and is configured to shape the extruded product P extruded by the screw 5 into the shape shown in FIG. 2.

An optical dimension measuring device 8 is placed in front of the extruder 1 (on the right side in Figure 1) and continuously measures the dimensions (width) of the extruded product P by irradiating it with light. ing. A microwave heating device 10 having a conveyor 9 inside is disposed in front of the optical dimension measuring device 8, and the extruded product P is heated and vulcanized while moving on the conveyor 9. It has become. In front of the microwave heating device 1o, a hot blast furnace 12 having a conveyor 1l is disposed so that the extruded product P is heated and maintained at a constant temperature while moving on the conveyor 1l, and vulcanization is continued. It has become.

The vulcanized molded product Q conveyed through the conveyor 11 in the hot-blast stove 12 has a shape as shown in FIG. 2, and is used as a weather strip for window frame rubber of automobiles.

Now, the rubber tape-like base material 2, which is the raw material, is stored in the storage container 3.
It is fed into the hopper 4 of the extruder 1, and further extruded forward by the screw 5 in the cylinder 6 of the extruder 1. Then, by passing through a mold 7, it is formed into a shape approximately as shown in FIG. 2 and extruded. The extruded product P is vulcanized by being conveyed while being heated on the conveyor 9 in the microwave heating device 10, and then vulcanized by being conveyed while being heated on the conveyor 11 in the hot air stove 12. The process continues, and a product, which is a vulcanized molded product Q, is taken out.

There is a difference between the average dimension value X of the extrusion molded product P and the Mooney viscosity M of the rubber material supplied to the extruder, and as the Mooney viscosity M of the rubber material becomes smaller, the extrusion molded product P becomes softer.
If the Mooney viscosity M of the rubber material becomes smaller, and conversely the Mooney viscosity M of the rubber material increases, it will become harder and the dimensions of the extruded product P will increase, so there is a positive correlation and the following equation holds true.

X=0.3 2 8 6M+9.4 5・・・・・・■
However, M is 45-49.

In addition, the amount of change ΔR in the rotation speed of the screw 5 in the extruder 1
The difference between ΔY and the change in the average dimension of the vulcanized product Q is that when the rotation speed of the screw 5 is decreased, the dimensions of the vulcanized product Q are also reduced, and conversely, when the rotation speed of the screw 5 is increased, the size of the vulcanized product Q is decreased. Since the dimensions of the vulcanized product Q also increase, there is a positive correlation, and the following equation holds true.

ΔY = 0. ２ Although the size of P becomes smaller, it becomes easier to foam and the size of the vulcanized crystal Q becomes larger.On the other hand, when the Mooney viscosity M of the rubber material increases, it becomes harder and the size of the extruded product P becomes larger, but foaming becomes easier. Since the dimensions of the vulcanized product Q become smaller as a result, there is a negative correlation, and the following equation holds true.

Y=-0.257M+37.8...■Here,
Specifically, when the dimensions of the vulcanized product Q are set to 26.01, the average value X of the dimensions of the extruded product P is 24.53+am
When the diameter changes from 25.55 mm to 25.55 mm, it is considered that the Mooney viscosity M changes from 45.9 to 49.0 from the above equation (2). With respect to this change in Mooney viscosity M, the average value Y of the dimensions of the vulcanized molded product Q is 26. OOmm to 2
It is predicted that it will decrease to 5.21mm, and the amount of change ΔY is 0.
．． It will be 79mm. Therefore, from equation (2), ΔR is 3. 9
5 rpm, and it is sufficient to increase the rotational speed of the screw 5 by this amount.

In this way, there is a certain correlation between the dimensional average value X of the extruded product P, the amount of change ΔR in the rotation speed of the screw 5, and the average dimension value Y of the vulcanized product Q. Measure the average value X of the dimensions of product P, and based on the amount of change,
Since the rotational speed of Scrier 5 is controlled, even if the composition (physical properties) of the rubber material changes from batch to batch, it can quickly respond to the change and set the dimensions of the vulcanized product Q with high precision. can.

Furthermore, unlike the conventional method, there is no method of controlling the rotational speed of the scratcher 5 based on the amount of change in the dimensions of the vulcanized product Q that has gone through the long process of the microwave heating device 10 and the hot air stove 12. Therefore, control loss during the long process of using the microwave heating device 10 and the hot air stove 12 required for vulcanization can be reduced.

As described above, according to the method for manufacturing a foamed rubber molded product of this embodiment, even if the rubber material changes from batch to batch, the dimensions of the vulcanized molded product Q can be set with high accuracy, and control loss can be avoided. It's been a while.

The present invention is not limited to the above-mentioned embodiments, and can be modified as desired without departing from the spirit of the invention. For example, it can be configured as follows.

That is, the foamed rubber material may be any material that can be made into a foamed rubber molded article, and in addition to EP[)M, ethylene-propylene copolymer rubber (EPM) or the like may also be used.

[Effects of the Invention] According to the method for producing foamed rubber of the present invention, the dimensions of the vulcanized product can be set with high accuracy even if the rubber material changes from batch to batch, and there is an effect that control loss is less likely to occur. play.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are diagrams showing embodiments of the present invention,
Figure 1 is a schematic front view showing the manufacturing setup for foam rubber molded products;
FIG. 2 is a perspective view of a foamed rubber molded product as a vulcanized molded product. DESCRIPTION OF SYMBOLS 1... Extruder, 2... Tape base material as a rubber material, 5... Screw, P... Extrusion molded product, X...
Average dimensions of extruded products

Claims (1)

[Claims] 1. Rubber material (2) is transferred from the extruder (1) to the screw (5
), the extrusion molded product (P
), and based on the increase or decrease in the dimension (X), the rotation speed of the screw (5) of the extruder (1) is similarly increased or decreased. A method for manufacturing foam rubber molded products.