JPH0411372B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a composite extrusion molding method in which a plurality of materials such as rubber and resin are separately supplied and extruded together. For example, this method is suitable for making a rubber hose with an airtight inner layer and a durable outer layer, or for extruding objects of different materials and shapes into one at the outlet.

<Prior Art> It is well known to carry out multiple extrusion molding using multiple extruders and a central discharge head (Japanese Patent Laid-Open No. 54-58762, etc.).

The front cutting heat generating machine, commonly known as the shear head, has been developed in recent years, and compared to the conventional method of heating rubber and resin from the outside using electric heat to reach the vulcanization and crosslinking temperature, it generates heat evenly from within. Because the equipment was simple, it came to be widely used in molding material supply devices (Japanese Patent Application Laid-Open No. 59-49952, etc.).

However, the heat generation conditions are complex and the temperature rises rapidly, so advanced on-site technology is required to control the temperature.

The multi-extrusion molded product produced by multiple extruders and central discharge heads must be passed through a vulcanization and crosslinking line, heated to the required temperature, and reacted for the required time to strengthen it.

Since the above-mentioned line uses hot air as a high-frequency current, the outer periphery is mainly heated, and it is difficult for the heat to reach the inside of the material, which has poor thermal conductivity.

Therefore, the present applicant quickly installed a shear heating device in the extruder, used this to heat only the inner layer of a product with different inner and outer layers, such as a rubber hose, to around the required temperature at the same time as extrusion molding, and added a normal layer on top of this inner layer. They developed and put into practical use a method in which the outer layer is coated using an extrusion molding machine, and then passed through a vulcanization and crosslinking line to heat the outer layer to the required temperature.

<Problems to be Solved by the Invention> This conventional method is a common sense method for achieving the required temperature in two steps because it is a two-layered product, and it is meaningful because it can be used by making use of the existing vulcanization and crosslinking lines. However, the high frequency current and hot air that are the heat sources for the above line are significantly more expensive than those using shear heat generation.

The inventors have developed such a composite product in one step.
In other words, the challenge was to develop a new method that would heat each material to its respective vulcanization and crosslinking temperatures and extrude it all at once using just a combination of an extruder and a shear heating machine.

<Means for solving the problems> The composite extrusion molding method for rubber and resins of the present invention includes the following:
Multiple types of rubber or resin are kneaded by each extruder at a pressure and temperature that does not cause vulcanization or crosslinking reactions, and then pushed into each shear heating machine. By temperature control based on the size of the gap with the inner wall of the heating machine and the rotation speed of the mandrel, each pushed-in material is heated to its respective reaction temperature and immediately sent to each receiving port of the central discharge head, and the inside of the central discharge head is heated. Then, each material is bonded in the desired arrangement and desired cross-sectional shape at the above-mentioned reaction temperature, discharged as a composite material in the desired shape, and immediately sent to a conventional vulcanization and crosslinking line. The method is characterized in that only cooling is prevented, and the temperature of each material constituting the composite material is maintained near the initial reaction temperature for a required period of time.

<Function> Conventionally, there has been an idea to add a shearing heat generator to an extrusion molding machine and extrude the material heated to near the vulcanization and crosslinking temperature from the molding section. However, it is extremely difficult to control the temperature of materials using shear heat generation, and the fluctuation range is large, so it is generally said that adding a shear heat generator can reduce heat consumption in the vulcanization and crosslinking lines rather than not adding a shear heat generator. It remained in use.

As partially disclosed in Japanese Patent Application Laid-Open No. 59-49952, the present applicant has intensively researched and developed temperature control for shear heat generators, and as a result, has developed a method for vulcanization and crosslinking lines that utilize shear heat generation as in the past. Rather than using a time-consuming preheating method to bring the material to the required temperature, we have developed an on-site technology that allows the material to be completely controlled to the required temperature using only a shear heating device.

This invention is a new composite molding method made possible by the field technology, and by adding a shear heating machine to each extruder, which conventionally sent extruded material to each receiving port of a central discharge head, each Since materials are combined at the required vulcanization and crosslinking temperatures, the vulcanization and crosslinking lines, which were traditionally the main role in temperature control, have been downgraded to mere temperature maintenance means.

<Example> FIG. 1 is a cross-sectional explanatory diagram of an apparatus according to an embodiment of the present invention, in which the extruder described above is 1, its screws are 1a,
A material input port is designated as 1b, a shear heating device is designated as 2, its mandrel is designated as 2a, a central discharge head is designated as 3, its material receiving ports are designated as 4 and 4', material passages are designated as 5 and 5', and discharge port is designated as 6. The motor that rotates the screw 1a and the mandrel 2a is M, and the extrusion molded product is W. Product W is in this case a double hose whose cross section is shown in FIG.

The extruder 1 and shear heating machine 2 shown in the figure are both the most common examples. Temperature control of the shear heating machine 2 is complicated, but mainly the mandrel 2a and the heating machine 2
It is controlled by the size of the gap with the inner wall of the mandrel 2a and the rotation speed of the mandrel 2a. FIG. 3 shows an XX cross section of the discharge side cylindrical portion 3a of the concentrated discharge head 3. Inside the outer cylinder of the discharge-side cylinder part 3a, there is a cylindrical partition wall 3b that separates both material passages, and in the center thereof, a short core material 3c that matches the inner diameter of the product hose is supported by support arms 7 that are distributed. has been done. Both materials, which are separated from the inside and outside by the cylindrical partition wall 3b, are narrowed down by the mouthpiece 6a of the discharge port 6 and joined inside and outside, and are discharged as a composite material in a desired shape, and sent to a conventional vulcanization and crosslinking line (not shown). The temperature of each component of the composite material (product W) is maintained at around the initial reaction temperature for a required period of time by the feeding and its heat-insulating action, and the reaction is completed. Since there is a permissible range for the reaction temperature and required time, it is sufficient to prevent cooling in the above line.

The passages from the material receiving ports 4, 4' of the discharge head 3 to the annular passages 5, 5' in the discharge side cylindrical part 3a are as follows:
This is left to the designer, but since it does not have the fluidity of an aqueous solution, care must be taken to ensure that there are no spots where the material stagnates. In the illustrated embodiment, the material on the inner circumferential side of the hose, that is, the material entering from the receiving port 4, is made into one straight passage, and the material on the outer circumference is divided into several passages.

The embodiment of FIG. 5 is the same as that of FIGS. 1 and 2,
This is an example in which an extruder 1 and a shear heating machine 2 are arranged in parallel so that the floor space of the factory can be used effectively.

The central discharge head 3, which has the role of receiving a plurality of materials and combining them into a desired arrangement and cross-sectional shape, must have a material passage and a discharge port designed according to the implementation conditions.

As an example W' of an extruded product that is not cylindrical, FIG. 6 shows a cross section of a central discharge head 3 used to make a gap filler for an automobile body, commonly known as a weather strip, as shown in FIG.

The material entering from the receiving port 4 is made into a circular arc cross section as shown in the upper part of Fig. 7 in the passage 5, and the material coming from the receiving port 4' is made into a plate-like cross section as shown in Fig. 7 in the passage 5'. . Both are pressed together at the mouthpiece 6a of the discharge port 6, and are integrated into a desired cross-sectional shape and exit.

Although two embodiments have been described above, it goes without saying that the embodiments of the present invention can be varied and applied in various ways by the designer using known techniques depending on the implementation conditions, and can also be applied by combining three or four types of materials. Things are also easy.

<Effects of the Invention> The present invention is capable of preheating only the inner layer material, which is difficult to heat in the vulcanization and crosslinking lines, to approximately the required temperature when making an extrusion molded product that is a composite of two or more types of rubber and resin. This paved the way for the shear heating machine, which had only been used for a limited time, to be used as a heating control means for the first time to completely raise the vulcanization and crosslinking temperature to the central discharge head.

By arranging combination sets of extruders and shear heat generators equal to the number of materials to be composited, and concentrating the materials to the central discharge head, each material is extruded in the desired arrangement and in the desired cross-sectional shape.

When composited and then heated in a vulcanization and crosslinking line, the outer layer material becomes high temperature and the inner layer material becomes low temperature.
According to this invention, since both the inner layer and the outer layer can be composited at exactly the required temperature, the quality is improved, and since they are composited at a higher temperature than in the past, the integration bond strength is also strengthened.

In addition to the above quality improvement, according to this invention,
The heating process of the conventional vulcanization and crosslinking lines is not required, and only the heat retention process is required, which simplifies the manufacturing process, saves heating energy, and reduces the equipment area.

[Brief explanation of drawings]

Fig. 1 is a plan sectional view of an embodiment of the present invention, Fig. 2 is a perspective view thereof, Fig. 3 is a sectional view taken along line XX in Fig. 1, and Fig. 4 is a cross-sectional view of the molding machine shown in Figs. 1 and 2. Product cross section,
FIG. 5 is a plan sectional view showing an application example of the embodiment shown in FIGS. 1 and 2, FIG. 6 is a sectional view of the concentrated discharge head of another embodiment, and FIG. 7 is a sectional view of the extruded product using the discharge head. . 1... Extruder, 2... Shear heating machine, 3... Centralized discharge head.

Claims (1)

[Scope of Claims] 1. A plurality of types of rubbers or resins are kneaded by respective extruders at pressures and temperatures that do not cause vulcanization and crosslinking reactions, and then pushed into respective shear heat generators to produce each of the above-mentioned shear heat generators. The temperature is controlled mainly by the size of the gap between the mandrel and the inner wall of the heat generating machine, and by the rotation speed of the mandrel, to raise the temperature of each pushed material to the above-mentioned reaction temperature and immediately send it to each receiving port of the central discharge head. Inside the concentrated discharge head, each material is joined in the desired arrangement and desired cross-sectional shape under the above-mentioned reaction temperature, discharged as a composite material in the desired shape, and immediately subjected to conventional vulcanization, A composite of rubber and resin, which is fed to a crosslinking line, where the temperature of each material constituting the composite material is maintained at around the initial reaction temperature for a required period of time by preventing only cooling. Extrusion method.