JPS5933822B2 - Manufacturing method of magnetic gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic gasket used, for example, in a refrigerator door.

The conventional magnetic gasket, as shown in Figure 1,
It is constructed by inserting a magnet 1 made of flexible synthetic resin or rubber, barium ferrite, etc. into a magnet bag-shaped portion 3 of a gasket body 2 made of flexible soft vinyl chloride or the like.

In this case, the magnet 1 is attached to the bag-like part 3 of the gasket body 2.
When inserting the gasket into a gasket, the gap is extremely small and the insertion work is difficult, and the magnet moves within the bag-shaped part 3 when the door is opened and closed, so the inner surface of the bag-shaped part 3 of the gasket body 2 is worn out and the magnetic Due to the magnetic force between the body 4 and the magnet 1, when the door is opened and closed, the corners 5 and 6 of the bag-shaped part 3 that are in contact with the magnetic body 4 are repeatedly subjected to concentrated stress, which may cause them to break due to fatigue. Furthermore, in crystalline resins such as vinyl chloride, molecular chains are aligned in the extrusion direction. That is, because it has the property of orientation, its tensile strength is strong in the extrusion direction, but weak in the direction perpendicular to the extrusion direction. Therefore, the bag-shaped portion 3 of the gasket body 2 also had a tendency to be easily torn in the longitudinal direction.
The manufacturing method of the present invention is a novel method for manufacturing a magnetic gasket that can improve all of the above-mentioned conventional drawbacks.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacturing method of the present invention will be described below with reference to the accompanying drawings showing the state in which the manufacturing method of the present invention is implemented. During extrusion molding of the gasket body 10 made of flexible resin such as soft vinyl chloride, only the bag-shaped portion 11 is made into the state shown by the dotted line in FIG. 2 by using a vacuum sizing mold or by blowing compressed air. By expanding and forcibly stretching the resin, the molecular structure of the resin is oriented in a direction perpendicular to the extrusion direction and molded. After inserting a string-like magnet 12 formed by a separate extruder into the bag-shaped part 11 stretched and formed in this way, it is passed through a constant temperature oven or by blowing hot air. ,
Only the stretched bag-shaped portion 11 contracts and tightly adheres to the outer periphery of the magnet 12. When the magnet 12 is inserted into the magnetic gasket formed as described above,
Since the bag-like part 11 has been enlarged by stretching, the insertion work is not only significantly easier, but also the bag-like part 11 is contracted by heat after being inserted and is tightly attached to the magnet 12, thereby sealing the movement of the magnet 12 when the door is opened and closed. , the wear between the magnet 12 and the inner surface of the bag-shaped portion 11 is eliminated. Furthermore, stretching in the direction perpendicular to the extrusion direction changes the arrangement of the molecules of the synthetic resin, improving the tear strength in the longitudinal direction of the bag-like part 11 of the gasket body, which can cause damage to the gasket due to fatigue when opening and closing the door. It improves destruction.
As described above, in the manufacturing method of the present invention, only the bag-like part is stretched during molding of the gasket body forming the continuous bag-like part, and after the magnet is inserted, heat is applied to the bag-like part to stretch only the bag-like part. This is characterized by the fact that it shrinks and holds the magnet and gasket body together, which not only greatly simplifies the manufacturing process of the magnet gasket molded in this way, but also prevents damage to the gasket bag-shaped part. This has an excellent effect that can be considered as an improvement.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional magnetic gasket, and FIG. 2 is a cross-sectional view of a magnetic gasket showing a state in which the manufacturing method of the present invention is implemented. 10...Gasket body, 11...Bag-shaped portion, 12...Magnet.

Claims (1)

[Claims] 1. When molding the gasket body that forms a continuous bag-like part, only the bag-like part is stretched, and after inserting a string-shaped magnet, heat is applied to the bag-like part to cause only the bag-like part to shrink. A method for manufacturing a magnetic gasket, characterized by integrally holding a magnet body and a gasket body.