JP2004108752A - Gasket for refrigerator and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasket usable for a long period by laminating a thin protecting film layer on the abutment surface of the gasket to be mounted at the inner face peripheral edge of a front opening/closing door of any kind of refrigerator to produce less friction resistance with lighter operation in opening/closing the door, and its manufacturing method. <P>SOLUTION: A structural material for a gasket body to be mounted at the inner face peripheral edge of the front opening/closing door of the refrigerator is formed of a thermoplastic elastomer and the thin protecting film layer of a hard synthetic resin is laminated on the abutment member thereof. With the use as the hard synthetic resin a mixed synthetic resin formed by mixing a synthetic resin of a base material having smaller melting viscosity and higher fluidity with powder and particles of additives having greater melting viscosity and lower fluidity than the base material, a number of rugged coarse portions are formed on the surface of the thin protecting film layer by an extrusion molding machine. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a gasket for a refrigerator in which a thin protective film layer for reducing the frictional resistance for facilitating the opening and closing of the door is formed on the front side of a gasket attached to the inner peripheral edge of the front opening and closing door of various refrigerators, and a method of manufacturing the same. Things.
[0002]
[Prior art]
Conventional refrigerator gaskets are generally made of soft vinyl chloride, which is very easy to manufacture and inexpensive. However, the use of the soft vinyl chloride is a serious problem due to the generation of hydrogen chloride during incineration and environmental problems such as dioxin. In addition, there is a problem that a strong force is required to open the front door because the frictional resistance is large when the front door is opened.
[0003]
Due to the above problems, olefin-based and styrene-based thermoplastic elastomers are currently used for refrigerator gaskets. However, since the surface of the thermoplastic elastomer is very soft, there is a disadvantage that the surface is worn or a weak sound is generated when the refrigerator is opened and closed.
[0004]
[Problems to be solved by the invention]
The present invention has been made to solve the above-mentioned problems, and a hard synthetic resin having a hardness of 90 or more (JIS K7215A hardness) is provided on a surface side of a gasket main body provided on an inner surface of a front opening / closing door in contact with a refrigerator main body. It forms with. This hard synthetic resin is formed by laminating a thin thin protective film layer having abrasion resistance and a small friction coefficient.
In addition, if the outer surface of the thin protective film layer is smooth, the adhesion between the refrigerator and the front open / close door is increased, so that the opening / closing operation of the opening becomes very heavy and low noise is generated. In order to achieve this, a rough surface portion with irregularities is formed on the surface of the thin protective film layer.
[0005]
[Means for Solving the Problems]
According to the present invention, in order to achieve the above object, a gasket body to be sealed in the longitudinal direction is formed of a thermoplastic elastomer, and a thin protective film layer is laminated with a hard synthetic resin on a surface in contact with the gasket body. I do. As the hard synthetic resin of the thin protective film layer, the melt viscosity is small, and the high-fluidity base material synthetic resin has a higher melt viscosity than the base material synthetic resin, and the powders and particles of the low-flowability additive material. A mixture of the above synthetic resins is extruded to form a large number of uneven surface portions on the surface of the thin protective film layer.
Further, as the hard synthetic resin of the thin protective film layer, as a base material of a synthetic resin having a low melting point, powder of an additive having a higher melting point than the base material, synthetic resin of particles or mica, inorganic powder such as molybdenum, After extrusion molding of the mixed synthetic resin obtained by mixing the particles, a mixed synthetic resin is used which forms a large number of uneven surface portions on the surface of the thin protective film layer.
Further, the thermoplastic elastomer for forming the gasket body is injected into the first extruder, the hard synthetic resin for forming the thin protective film layer is injected into the second extruder, and then formed in one die. Is what you do.
[0006]
【Example】
The embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a longitudinal gasket main body (3) is mounted on an inner peripheral edge of a rotary front door (2) of a refrigerator (1).
On the gasket body (3), an insertion piece (5) to be inserted into the front opening / closing door (2) is formed projecting rearward. Further, a thin protective film layer (7) made of a hard synthetic resin is adhered and laminated on the surface of the contact portion (6) of the gasket body (3). As the hard synthetic resin forming the thin protective film layer (7), the melt viscosity is small, and the melt viscosity is larger than the synthetic resin of the base material and the low flowability is added to the synthetic resin of the base material having high fluidity. The thin protective film layer (7) is formed after extrusion molding with a mixed synthetic resin obtained by mixing powders and synthetic resins of particles, and a large number of uneven surface portions (R) are formed on the surface of the thin protective film layer (7). 8) (8) (8) ... are formed.
[0007]
Further, as the hard synthetic resin of the thin protective film layer (7), a powder of an additive having a higher melting point than the base material, a synthetic resin of particles or an inorganic material such as mica, molybdenum, etc. After extrusion molding of a mixed resin obtained by mixing powder and particles of the above, a large number of rough surface portions (8), (8), (8)... Are formed on the surface of the thin protective film layer (7). Things.
[0008]
Next, according to the manufacturing method of the embodiment shown in FIG. 5, the thermoplastic elastomer for forming the gasket body (3) is injected into the first extruder (15) to form the thin protective film layer (7). The mixed synthetic resin of the hard synthetic resin is injected into the second extruder (17), and then, through the respective flow pipes (20) and (20), the two are laminated inside the mold die (16) to form the thin protective resin. Simultaneously with the formation of the film layer (7), the operation of the second extruder (17) causes a large number of uneven surface portions (8), (8), (8),... On the surface of the thin protective film layer (7). It is formed integrally inside the mold die (16). Thereafter, the gasket body (3) passes through a cooling water tank (18), and is cut into a predetermined length by a take-off machine (19) by various methods.
[0009]
As shown in FIG. 4, an air chamber (11) is formed in the gasket body (3) adjacent to the magnet insertion chamber (9) in the longitudinal direction. Further, in the magnet insertion chamber (9), a thin protective film layer (7) provided with the above-described rough surface portion (8) on the inner peripheral surface thereof in order to make the magnet (10) slippery and easy to insert. (7) is adhered and laminated. Reference numeral (12) denotes a sealing piece, (13) denotes an upper rotating front opening / closing door, and (14) denotes a lower drawer front opening / closing door.
[0010]
Next, the material used in the present invention will be described in detail. The gasket main body (3) is made of a thermoplastic elastomer such as an olefin-based or styrene-based thermoplastic elastomer having a hardness of 85 or less (JIS K7215A hardness). It is a foam.
As the hard synthetic resin forming the thin protective film layer (7), an olefin-based synthetic resin such as polyethylene or polypropylene having a hardness of 90 or more (JIS K7215A hardness), a styrene-based synthetic resin, or a urethane-based synthetic resin is used. The thickness of the thin protective film layer (7) is preferably 0.05 mm or less in order to maintain the softness of the gasket body (3).
[0011]
Further, as the mixed synthetic resin of the hard synthetic resin of the uneven rough surface portions (8) and (8) formed on the surface of the thin protective film layer (7) of the present invention, first, the synthetic resin of the base material is melted. A low viscosity polyethylene having a flow rate of 0.5 g or more / 10 minutes (ASTM D1238 190 ° C.) is used.
In addition, as a powder or particle additive, a high-viscosity polyethylene having a melt flow rate of 0.1 g or less / 10 minutes (ASTM D1238 at 190 ° C.) is used.
[0012]
Next, at the time of extrusion molding, the low-viscosity polyethylene of the base material is in a completely molten state in the mold die (16), but the high-viscosity polyethylene of the additive material has a powder and particles exceeding the melting point. Is extruded while maintaining the shape of powder and particles to some extent without liquefaction. Therefore, after extrusion, a large number of uneven surface portions (8) (8) are formed on the outer surface of the thin protective film layer (7). ) Is what is formed.
[0013]
The following materials are used as the material of the mixed synthetic resin of the hard synthetic resin for forming the rough surface portions (8) and (8) on the outer surface of the thin protective film layer (7). That is, as a synthetic resin base material of a low melting point synthetic resin such as an olefin, styrenic or urethane type, as a synthetic resin having a low melting point, an olefin or styrene having a higher melting point than the base material is used. Powder, urethane-based, nylon-based, etc. powder and particle additives are mixed.
In the extruder, the synthetic resin of the base material having a low melting point is liquefied, but the powder and particles of the additive of the synthetic resin having a high melting point are numerous on the outer surface of the thin protective film layer (7) depending on the degree of melting. Is formed.
[0014]
Even when an additive of inorganic powder or particles such as molybdenum or mica is mixed, the powder or particles of the additive such as molybdenum or mica is extruded without melting during extrusion molding, and then a thin protective film layer (7) is formed. A large number of uneven rough surface portions (8) (8) on the outer surface of (1) are formed.
[0015]
【The invention's effect】
Since the present invention is configured as described above, when it is used as a gasket for a refrigerator, environmental problems such as dioxins are caused by replacing a constituent material of soft vinyl chloride such as a conventional gasket with a thermoplastic elastomer. In addition, the thermoplastic elastomer has an excellent effect on recyclability, weight reduction, and the like. Further, since the thin protective film layer is formed with a hard synthetic resin at the contact portion of the gasket, there is an effect that the wear resistance is improved and the durability of the gasket is improved. Further, as the hard synthetic resin of the thin protective film layer, the melt viscosity is small, and the synthetic resin of the base material having high fluidity has a higher melt viscosity than the synthetic resin of the base material, and the powder of the additive having low flowability, Using a mixed synthetic resin mixed with particles and forming a large number of uneven surface portions on the surface of the thin protective film layer by extrusion molding, the surface of the thin protective film layer can be extremely reliably formed at the time of extrusion molding. In addition, there is an excellent effect that a rough surface portion is formed, and the frictional resistance of the surface of the thin protective film layer is extremely reduced, and the opening and closing operation of the front opening and closing door is extremely light. Also, there is an effect of preventing generation of a weak sound or the like. Further, as a hard synthetic resin of the thin protective film layer of the gasket, a base material of a synthetic resin having a low melting point, a powder of an additive having a higher melting point than the base material, a synthetic resin of particles, or an inorganic powder such as molybdenum and mica By forming an uneven rough surface portion on the surface of the thin protective film layer after extrusion molding with a mixed synthetic resin mixed with particles, a rough surface portion can be easily and reliably formed by each material inside the extruder. At the same time, the gasket has an effect that opening and closing operations are remarkably light because the frictional resistance of the surface is small. In addition, by using two extrusion molding machines and passing them through the inside of one mold die, the surface of the contact portion of the gasket body and the thin protective film layer can be easily and simultaneously polymerized and laminated. There is also an effect that can be done.
[Brief description of the drawings]
FIG. 1 is a perspective view of an open state in which the present invention is mounted on an opening / closing door of a refrigerator.
FIG. 2 is a cross-sectional plan view taken along line AA of FIG. 1 of the present invention.
FIG. 3 is a longitudinal perspective view of the gasket of the present invention.
FIG. 4 is a vertical sectional side view of the gasket of the present invention.
FIG. 5 is a side view of the gasket of the present invention in which an operation process using two extruders is partially omitted.
DESCRIPTION OF SYMBOLS 1 Refrigerator 2 Front opening / closing door 3 Gasket 5 Insertion piece 6 Contact part 7 Thin protective film layer 8 Rough surface part 9 Magnet insertion room 10 Magnet 11 Air room 15 First extruder 16 Die die 17 Second extruder 18 Cooling water tank

Claims (4)

The longitudinally sealed gasket main body mounted on the inner peripheral edge of the front opening and closing door of the refrigerator is formed of a thermoplastic elastomer. A gasket for a refrigerator, comprising: As the hard synthetic resin of the thin protective film layer, the melt viscosity is low, and the synthetic resin of the base material having a high fluidity has a higher melt viscosity than the synthetic resin of the base material, and the powder and particles of the additive material having a low flowability are used. 2. The gasket for a refrigerator according to claim 1, wherein a large number of uneven surface portions are formed on the surface of the thin protective film layer after extrusion molding by using a mixed synthetic resin obtained by mixing a synthetic resin. As the hard synthetic resin of the thin protective film layer, as a base material of a synthetic resin having a low melting point, powder of an additive having a higher melting point than the base material, synthetic resin of particles or mica, inorganic powder or particles of molybdenum or the like are used. 2. The gasket for a refrigerator according to claim 1, wherein a large number of uneven surface portions are formed on the surface of the thin protective film layer after extrusion molding by the mixed synthetic resin. The thermoplastic elastomer for forming the gasket body is injected into the first extruder, the hard synthetic resin for forming the thin protective film layer is injected into the second extruder, and then polymerized inside one die. 4. The method for producing a gasket for a refrigerator according to claim 1, wherein the gasket is laminated.

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