JPH0292510A - Preparation of composite packing - Google Patents

Abstract

PURPOSE:To make it unnecessary to make the vol. of semi-molded item larger than the vol. of a molding space and to attempt thereby to improve the yield of a material by filling a discontinued part of a semi-molded item such as a tube or semi-cylinders with a molten material which is the same material as a material constituting a coating layer pressed in a molding space through a path. CONSTITUTION:Each mold 10, 11 and 19 is heated up to around the m.p. of a material constituting a tube 4 or semi-cylindrical bodies 6 and 6 which is to be a coating layer 2 and pellets made of the same material are filled in a feeding space 21, where the pellets are melted. While a top force 10 and a bottom force 11 are separated each other, a composite packing raw material 9 is placed on a recessed part 13 formed on the upper face of the bottom force 11. The recessed part 13 of the upper face of the bottom force and a recessed part 12 of the bottom face of a top force are jointed together and the composite packing raw material 9 is heated in a molding space 14. A press mold 19 inserted in a recessed part of the cylinder 18 is lowered and the molten material in the feeding space 21 is pushed in the molding space 14 through a path 20. Discontinued part of the tube 4 or semi-cylindrical bodies 6 and 6 are filled thereby with the molten material pressed-in.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The method for manufacturing composite packing according to the present invention relates to an improvement in the method for manufacturing a packing for maintaining sealing properties in areas where chemical resistance is required. .

(Prior art) As shown in Fig. 2, an elastic rubber ring 1 is used as a packing to be attached to a seal part that requires chemical resistance.
A composite packing 3 in which the periphery is covered with a coating layer 2 having chemical resistance such as fluororesin is widely used.

As a method for manufacturing such a composite packing 3, a method such as that disclosed in Japanese Patent Application Laid-Open No. 63-60811 has been known.

This publication discloses two manufacturing methods,
In either method, the surface of a core material made of an elastic material such as a rubber ring 1 is covered with a semi-molded body made of a material such as a fluororesin that constitutes a covering layer 2, and a composite packing 3 which is a completed product is formed. After forming a composite packing material with a slightly larger volume than that of the composite packing material, this composite packing material is fitted into the recesses formed on the opposing surfaces of the first mold and the second mold, and a molding space surrounded by both recesses is created. The composite packing material is compressed while being heated to around the melting temperature of the material (fluororesin, etc.) forming the coating layer, thereby forming the composite packing 3.

When making the composite packing material 9, as shown in Fig. 3,
A closed annular rubber ring 1 with a semicircular arc cross section
By sandwiching it between a pair of half cylinders 6.6, or as shown in Fig. 4,
By inserting the rubber string 5 forming the rubber ring 1 into the inside of the tube 4 forming the coating layer 2, and by shifting the seam 8 of the tube 4 and the seam 8 of the rubber string 5, both members 4. 5 into a ring shape.

As a method for making composite packing 3 from composite packing material 9 formed as described above, Japanese Patent Application Laid-Open No. 63-60811
The publication discloses two methods as mentioned above, and in the first method, as shown in FIG. The two recesses 12 and 12 are fitted into recesses 12.
．． The composite packing material 9 is compressed in a molding space 14 surrounded by a molding space 13 while being heated to around the melting temperature of the material such as fluororesin forming the coating layer 1.

In the vicinity of the recess 12 formed on the upper surface of the lower mold 11, grooves 15 and 15 are formed concentrically with the recess 12 to prevent fluorine from melting due to heating and compression and protruding from the molding space 14. It is designed to collect resin, etc.

In the case of the second method, as shown in FIG. 6, the upper mold 10 and the lower mold 11 are engaged with each other in the concave portion 12.13, and the two molds 10.11 are butted against each other. case,
Fine voids 17.17 are formed around the molding space 14, and the fluororesin and the like protruding from the molding space 14 are collected by the voids 17.17.

In both the first and second methods as described above, the upper mold 1
When the composite packing material 9 is heated and compressed in the molding space 14 formed between the lower die 11 and the lower die 11, the coating layer 2 is compressed.
A semi-cylindrical body made of a material such as fluororesin 6.6
, or a part of the tube 4 is melted, and this molten resin is applied to the joints between the half cylinders 6 and 6, and the joints 7 of the tubes 4.
etc., fill in discontinuities. The surplus of the molten resin other than that used to fill the discontinuous portion is poured into the groove 15.15 (
(in the case of Fig. 5), or air gap 17.17 (in the case of Fig. 6)
and solidifies there.

Then, the upper mold 10 and the lower mold 11 are separated, and the composite packing 3 in which the rubber ring 1 is covered with the coating layer 2 is taken out. The burrs caused by the material such as fluororesin entering the groove 15.15 and the gap 17.17 and solidifying are then removed.

(Problems to be Solved by the Invention) However, in the case of the conventional method for manufacturing composite packing as described above, the following disadvantages occur.

That is, in the case of the first method shown in FIG. 5, in order to send surplus molten resin to the groove 15.15 through the seam between the upper mold 11 and the lower mold 12, the heating temperature of the composite packing material 9 is lowered. It becomes necessary to strictly control the pressurizing force, pressurizing time, the volume of the tube 4 and the semi-cylindrical body 6, 6, etc., making it difficult to obtain a composite packing of good quality and resulting in poor product yield.

In addition, in the case of the second method shown in Figure 6, it is not necessary to regulate the heating temperature, pressurizing force, and pressurizing time as strictly as in the case of the first method, and the yield of the product will not deteriorate. However, unless the volume of the tube 4 and semi-cylindrical body 6.6 is strictly controlled,
Not only does this increase the number of exposed parts, resulting in a poor material yield, but it also takes time to remove the upper mold 10 and lower mold 11, resulting in poor workability and increased product costs.

The method of manufacturing composite packing of the present invention solves the above-mentioned disadvantages.

(Means for Solving the Problems) The method for manufacturing composite packing of the present invention is to cover the surface of a core material made of an elastic material with a semi-molded body made of a material forming a covering layer to form a composite packing material. , this composite packing material is fitted into recesses formed in opposing surfaces of a first mold and a second mold, and the composite packing material and the coating layer are placed in a molding space surrounded by both recesses. At the same time, a material made of the same material as the material forming the coating layer is heated to around the melting temperature of the material forming the coating layer, and a material made of the same material as the material forming the coating layer is heated into the forming space through a passage formed in either the first or second mold and leading to the forming space. A molten material is press-fitted to close any discontinuities in the semi-molded body.

(Function) In the method of manufacturing a composite packing of the present invention configured as described above, the discontinuous portion of the semi-molded body such as the tube or the half-cylinder body is press-fitted into the molding space through the passage. It is filled with a molten material of the same material as the material forming the coating layer. Since the first and second molds are heated to near the melting temperature of the material forming the coating layer, the molten material press-fitted into the molding space and the material forming the semi-formed body mix with each other and are cooled and solidified. After that, the semi-molded body originally existing in the molding space and the molten material press-fitted later become integrated.

Therefore, unlike in the conventional manufacturing method described above, it is not necessary to make the volume of the semi-molded body larger than the volume of the molding space, and the yield of the material is improved.

(Example) Next, the present invention will be explained in more detail while explaining the illustrated embodiment.

FIG. 1 is a sectional view of a pressure molding apparatus for carrying out the method of the invention.

This pressure molding device consists of an upper mold 10 and a lower mold 11,
Annular recesses 12.13 each having a semicircular cross section are formed at opposing positions of each mold 10.11.

Further, a cylinder recess 18 is formed on the upper surface of the upper mold 10, and a press mold 19 is tightly fitted into the cylinder recess 18. Furthermore, a plurality of passages 20 are provided between the inner surface of the cylinder recess 18 and the recess 12 formed on the lower surface of the upper mold 10.
．． 20, and a supply space 21 surrounded by the cylinder recess 18 and the end face of the mold 19 is formed in the recess 1 on the lower surface of the upper mold 10.
2 and a recess 13 on the upper surface of the lower mold 11
4, it is connected.

The composite packing material 9 as shown in FIG. 3.4 is heated and molded by a molding device consisting of the molds 10, 11, and 19 configured as described above to form the composite packing material 3 as shown in FIG. 2.
In this case, each of the molds 1O111 and 19 is made of the material (
For example, fluororesin) is heated to around the melting temperature, and
The supply space 21 is filled with pellets 22 made of the same material (fluororesin), and the pellets 22 are melted within the supply space 21.

When the composite packing material 9 is heat-formed to form the composite packing 3 after the above preparation work is completed, first, the composite packing material 9 is formed on the upper surface of the lower mold 11 with the upper mold 10 and the lower mold 11 separated from each other. A composite packing material 9 as shown in FIG. 3 or 4 is placed on the recessed portion 13. Note that the composite packing material 9 is preformed into a shape that matches the recess 13 in advance.

In this way, once the composite packing material 9 is placed in a predetermined position, the upper mold 10 and the lower mold 11, which had been separated from each other until then, are brought closer together, and the recess 13 on the upper surface of the lower mold and the recess 12 on the lower surface of the upper mold The composite packing material 9 is heated in the molding space 14 surrounded by both recesses 12, 13.

At the same time, the cylinder recess 18 formed in the upper mold 10
The mold 19 fitted in the mold 19 is lowered, and the molten material present in the supply space 21 is passed through the passages 20, 20 into the molding space 1.
Push it to 4.

As a result, the tube 4 (
A discontinuity in a half-formed body, such as a half-cylinder 6.6 (see FIG. 4) or a half-cylindrical body 6.6 (see FIG.
4 is filled with molten material that is forced into the hole.

The upper mold 10 and the lower mold 11 surrounding the molding space 14 have a coating layer 2
The molten material, which is heated to around the melting temperature of the material such as fluororesin that forms the tube 4 or semi-cylindrical body 6.6 for forming the tube 4 and which is press-fitted into the molding space 14, and the tube 4.
Alternatively, since the material forming the semi-cylindrical body 6.6 is the same, the molten material press-fitted into the molding space 14 later and the material forming the semi-molded body such as the tube 4 or the semi-cylindrical body 6.6 are the same. are mixed with each other, and after cooling and solidifying, the semi-formed bodies such as the tube 4 or half-cylindrical body 6.6 that originally existed in the molding space 14 and the molten material press-fitted later become one, forming a composite packing. No. 3 coating layer 2 is constituted.

In the case of the present invention, as described above, since the molten material is press-fitted into the molding space 14 later, the molten material generated by the melting of the semi-molded body such as the tube 4 or the semi-cylindrical body 6.6, There is no need to close the discontinuous portion of the semi-molded body. For this reason, as in the case of the conventional manufacturing method described above, a composite packing material 9 is made of a rubber ring 1 or a rubber string 5 and a semi-molded body such as a tube 4 or a semi-cylindrical body 6.6. It is no longer necessary to make the volume of the molding space larger than the volume of the molding space 14 (the external dimensions of the semi-formed body can be made smaller than the internal dimensions of the molding space 14), Since there is no occurrence of fraying, the yield of materials is improved.

In addition, since the necessary and sufficient amount of molten material for filling the gap is press-fitted from the supply space 21 into the molding space 14 through the passage 20.20, the gap does not remain unfilled and a high-quality composite is produced. Packing can be produced stably and product yields are improved.

Next, an experiment conducted by the present inventor will be explained.

The tube 4, which was a semi-molded product, was made of PFA and had an outer diameter of 4.0 ml11 and an inner diameter of 3.0 mm.

This tube 4 was heated to 300°C and the inner diameter was 44 m.
A rubber string 5 having a diameter of 2.9 mm was inserted into the tube 4 to form a composite packing material 9 as shown in FIG. 4.

This composite packing material 9 is stored in the molding space 14 of a molding device as shown in FIG.
, the lower mold 11 and the press mold 19 are heated to 330° C., and the molten resin produced by melting the pellet in the supply space 21 is press-fitted into the molding space 14, and after being left as it is for 10 minutes, the cooling breath is applied. As a result of pressure shaping by m (not shown), a high-quality composite packing 3 in which the periphery of the rubber string 5 was completely covered with PFA was obtained.

Similar experiments were conducted with the heating temperature of each mold 10, 11, 19 being 350° C., and as a result, composite packings of good quality were also obtained.

Furthermore, as a semi-molded body, we used a semi-cylindrical body 6.6 made of FEP and having a semicircular arc cross section as shown in Fig. 3, and as a result of conducting exactly the same experiment, we found that it was still a good quality composite body. Got packing.

In addition, in the above explanation, the case where the composite packing 3 having a circular cross section and an annular shape as a whole is manufactured is explained, but it is possible to make the composite packing 3 by changing the shape of the rubber ring 1, the tube 4, or the semi-cylindrical body 6. It is also possible to make a composite packing having a rectangular cross section or a composite packing 3 having a rectangular frame shape as a whole.

(Effects of the Invention) Since the method for producing composite packing of the present invention is configured and carried out as described above, it is possible to stably produce products of good quality and improve the yield of products. Instead, it is possible to reduce or even eliminate the flaws formed on the surface due to the resin material forming the coating layer, so it is possible to improve the yield of the material and reduce the cost of the product.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a pressure forming apparatus for carrying out the method of the present invention, FIG. 2 is a cross-sectional view showing an example of a composite packing made by the method of the present invention, and FIG. A sectional view showing the first example of the configuration of the packing material, FIG.
A plan view showing an example, FIG. 5 is a sectional view of a pressure molding apparatus used when implementing the first example of the conventional manufacturing method, and FIG. 6 is a cross-sectional view of a pressure molding apparatus used when implementing the second example It is a sectional view of a pressure molding device. : Covering layer, 3: Composite backing 5: Rubber string, 6: Semi-cylindrical body, : Composite packing material, 1 12.13: Recess, 14 17: Gap, 18, 20: Passage, 21: Part 1: Rubber ring, 2 ring, 4: tube, 7.8: seam, 9゛0: upper mold, 11: lower mold, : molding space, 15: groove, cylinder recess, 19: press mold, feeding space, 22: pellet. Mitsubishi Cable Industries Co., Ltd. Kozo (1 idiot)

Claims (1)

[Claims] (1) After forming a composite packing material by covering the surface of the core material made of an elastic material with a semi-molded body made of the material forming the covering layer, this composite packing material is divided into a first mold and a second mold. The above-mentioned composite packing material is fitted into the recesses formed on the opposing surfaces of the two recesses, and the composite packing material is placed within the molding space surrounded by both recesses.
The material forming the covering layer is heated to around the melting temperature of the material forming the covering layer, and the material forming the covering layer is heated to about the melting temperature of the material forming the covering layer, and is introduced into the forming space through a passage formed in either the first or second mold that leads to the forming space. A method for producing a composite packing, in which a molten material of the same material as the above is press-fitted to close the discontinuous portion of the semi-formed body.