JP2019109035A - Refrigerator door gasket - Google Patents

Abstract

To provide a light-weight refrigerator door gasket which achieves a small heat leak quantity.SOLUTION: A refrigerator door gasket 2 has: an attachment part 7 attached to a peripheral edge part 4 of a refrigerator door 1; a magnet holding part 8 which houses a magnet attracted to an opening peripheral edge of a refrigerator body storage chamber 3; and a thin bag-like part 9 which connects the attachment part 7 to the magnet holding part 8 in an expandable and contractable manner. The refrigerator door gasket 2 is formed by foam made of foamable vinyl chloride resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigerator door gasket, and more particularly to a refrigerator door gasket having a small amount of heat leakage.

  In recent years, the demand for reduction of consumption energy to refrigeration and refrigeration equipment such as a refrigerator and a vending machine has become strong, and efforts are being made to improve the cooling efficiency. One factor that hinders the cooling efficiency in the refrigeration device is the phenomenon that heat enters from the gap between the main storage room and the refrigerator door. In general, a gasket is provided at the periphery of the refrigerator door, and it is intended to suppress heat ingress by closing a gap with the opening edge of the refrigerator body storage room.

  FIG. 1 is a cross-sectional view showing a basic shape of a gasket of a refrigerator. A refrigerator door 1, a gasket 2 mounted on the refrigerator door, and a refrigerator body storage room 3 are shown in order from the top of the drawing. The refrigerator door 1 is in a state in which a gap is opened from the refrigerator body storage room 3.

  The refrigerator door 1 has a gasket attachment groove 5 along the peripheral edge 4. The refrigerator body storage chamber 3 has an opening edge 6 having magnetic response.

  The gasket 2 has a mounting portion 7 to the periphery of a relatively thick refrigerator door, a magnet holding portion 8 storing a magnet to be attracted to the periphery of the opening of the refrigerator main body storage room, the mounting portion and the magnet holding portion And a thin bag-like portion 9 for telescopically connecting them. The attachment portion 7 is formed with an arrow-shaped locking portion 10 so as to protrude. Then, the barbed locking portion 10 is pressed into the gasket mounting groove 5 of the refrigerator door 1 to fix the gasket 2.

  The refrigerator door gasket is required to have excellent thermal insulation in order to prevent heat from entering the refrigerator and dissipating internal cold air. Since the refrigerator door is frequently opened and closed over a long period of time, the refrigerator door gasket is required to be excellent in mounting strength and durability with respect to the refrigerator door while maintaining flexibility.

  Patent Document 1 discloses a method of reducing the amount of heat absorption of a heat insulation box for the purpose of saving power of a refrigerator or a showcase with regard to magnet packing of the refrigerator or the showcase (abstract). Specifically, it is described that a magnet packing for a refrigerator door excellent in heat insulation performance is manufactured by blending microballoons, which are hollow microspheres made of glass, with a vinyl chloride resin and extruding the deformed shape (( Paragraphs 0015 to 0016).

Unexamined-Japanese-Patent No. 5-118741

In the magnet packing of Patent Document 1, when carrying out profile extrusion, hollow microspheres made of glass mixed with vinyl chloride resin are caught or clogged in gaps, and the extruder does not operate normally, and thus the extrusion process Is difficult to progress smoothly. In addition, hollow microspheres do not have a sufficient heat insulating effect, and float on the surface of a molded product, resulting in a poor appearance of the product. Furthermore, the hollow microspheres do not bond well to the vinyl chloride resin, which reduces the mounting strength and durability of the magnet packing.
The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a refrigerator door gasket that is lightweight, has a small amount of heat leakage, and exhibits sufficient mounting strength and durability.

  According to the present invention, a thin wall is provided for telescopically connecting the mounting portion to the peripheral portion of the refrigerator door, a magnet holding portion storing a magnet to be adsorbed to the peripheral portion of the opening of the refrigerator main body storage room, and the mounting portion and the magnet holding portion. And a refrigerator door gasket comprising a foam of a foamable vinyl chloride resin composition.

  In one embodiment, the foam has a closed cell structure.

  In one embodiment, the foam has a foam rate of 15-40%.

  In one embodiment, the foam has a Shore A hardness of 60A to 75A.

  In one embodiment, the foamable vinyl chloride resin composition comprises 100 parts by weight of a vinyl chloride resin, 50 to 85 parts by weight of a plasticizer, 40 to 80 parts by weight of an inorganic filler, and 1.3 to 3 parts by weight of a foaming agent. And 2.4 to 5.5 parts by weight of an acrylic processing aid.

  The present invention also provides a refrigerator door having any of the above refrigerator door gaskets.

  The present invention also provides a refrigerator having the refrigerator door.

  According to the present invention, a refrigerator door gasket is provided that is lightweight, has a small amount of heat leakage, and exhibits sufficient mounting strength and durability. The refrigeration apparatus having the refrigerator door gasket of the present invention has high cooling efficiency and consumes low energy.

It is sectional drawing which shows the basic shape of the gasket of a refrigerator. It is an enlarged photograph which shows the refrigerator door gasket cross section of this invention. It is an enlarged photograph which shows the conventional refrigerator door gasket cross section.

  The refrigerator door gasket of the present invention comprises a foam of a foamable vinyl chloride resin composition. The foamable vinyl chloride resin composition is a composition containing a vinyl chloride resin, a plasticizer, an inorganic filler and a foaming agent, and preferably further containing a processing aid, a modifier and the like.

  As the vinyl chloride-based resin used in the present invention, any of those conventionally used as materials for foam molded articles can be adopted. For example, homopolymer of vinyl chloride monomer; Copolymer of a monomer and a polymerizable monomer other than a vinyl chloride monomer; a graft copolymer obtained by grafting a vinyl chloride monomer to a polymer other than a vinyl chloride resin; or a dry process of these And chlorinated vinyl chloride polymers obtained by post-chlorination using conventionally known methods such as a wet method, and the like, and further, mixtures of these polymers and copolymers are also included.

  When the average degree of polymerization of the vinyl chloride resin is too small, the mechanical strength, particularly the impact resistance, of the molded article decreases. On the other hand, if it is too large, the melt viscosity at the time of molding may be high, the temperature of the molding may be high, shear heating may be intense, and injection molding may be difficult, and foam defects may occur. Therefore, 400 to 2500 are preferable, and more preferably in the range of 1000 to 1400.

  The polymerizable monomer other than the vinyl chloride monomer is not particularly limited as long as it has a reactive double bond and can be copolymerized with the vinyl chloride monomer, for example, ethylene, propylene, Α-olefins such as butene-1; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; acrylic esters such as methyl acrylate and ethyl acrylate; methyl methacrylate, ethyl methacrylate, Methacrylic acid esters such as phenyl methacrylate; aromatic vinyls such as styrene and α-methylstyrene; halogenated vinyls such as vinylidene chloride and vinyl fluoride; N-substituted maleimides such as N-phenyl maleimide and N-cyclohexyl maleimide And the like, which may be used alone It may be used and 2 or more types may be used together.

  It does not specifically limit as polymers other than vinyl chloride type resin used for the said graft copolymer, For example, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-ethyl acrylate Copolymer, ethylene-ethyl acrylate-carbon monoxide copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, chlorinated polypropylene etc. These may be used alone or in combination of two or more.

  The said plasticizer will not be specifically limited if it is a plasticizer generally used when manufacturing a polyvinyl chloride resin molded object. Specifically, for example, phthalate plasticizers such as di-2-ethylhexyl phthalate, dibutyl phthalate, diheptyl phthalate and diisodecyl phthalate, fatty acid ester plasticizers such as di-2-ethylhexyl adipate, diisobutyl adipate and dibutyl adipate Epoxidized ester plasticizers such as epoxidized soybean oil, polyester plasticizers such as adipic acid esters and adipic acid polyesters, trimellitic acid ester plasticizers such as tri 2-ethylhexyl trimellitate, triisononyl trimellitate, trimethyl phosphate And phosphoric acid ester plasticizers such as triethyl phosphate; and process oils such as mineral oil. The plasticizer may be used alone or in combination of two or more.

  More specifically, for example, for polyester plasticizers, preferred viscosity is 2400 to 6000 (25 ° C., MPa · s), specific gravity is 1.050 to 1.150 (20/20 ° C.), and epoxidation The soybean oil has an epoxidation rate of 6.0% or more and an acid value of 0.5 or less (KOH mg / g).

  When the amount of the plasticizer added is small, the extrusion moldability tends to decrease, and when the amount is large, the obtained molded body becomes soft and the attachment strength tends to decrease. Therefore, the amount of the plasticizer added is in the range of 20 to 200 parts by weight, preferably 30 to 120 parts by weight, and more preferably 50 to 85 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

  The said inorganic filler will not be specifically limited if it is an inorganic filler generally used when manufacturing a polyvinyl chloride resin molded object. Specifically, for example, silica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, ferrites, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, base Magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, dononite, hydrotalcite, calcium sulfate, barium sulfate, gypsum fiber, calcium silicate, talc, clay, miw force, montmorillonite, bentonite, activated clay, Sebiolite, imogolite, sericite, glass fiber, glass beads, silica balun, aluminum nitride, boron nitride, silicon nitride, carbon black, graphite, carbon fiber, carbon balun, charcoal powder, various metal powders, potassium titanate, sulfuric acid Magnesium titanate zirconia lead, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, zinc borate, various magnetic powder, slag fibers, fly ash, and a dewatered sludge. The inorganic filler may be used alone or in combination of two or more.

  When the addition amount of the inorganic filler decreases, the hardness of the refrigerator door gasket tends to decrease and the attachment strength tends to decrease. When the addition amount increases, the extrusion molding becomes difficult, and the surface properties of the obtained molded article deteriorate, and the durability Sex tends to decrease. Therefore, the addition amount of the inorganic filler is in the range of 10 to 200 parts by weight, preferably 20 to 140 parts by weight, and more preferably 40 to 80 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

  The blowing agent used in the present invention is preferably of the thermal decomposition type. Specifically, for example, pyrolytic inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate, ammonium carbonate and the like; N, N'-dinitrosopentamethylenetetramine, N, N'-dimethyl-N, N'-di Nitroso compounds such as nitrosotephthalamide; azo compounds such as azodicarbonamide and azobisisobutyronitrile; and thermal decomposition type organic foaming agents such as benzenesulfonyl hydrazide and sulfonyl hydrazide compounds such as toluene sulfonyl hydrazide. These foaming agents may be used alone or in combination of two or more.

  The amount of the foaming agent added is 0.3 to 10 parts by weight, preferably 0.6 to 6 parts by weight, and more preferably 1.3 to 3 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. If the amount added is less than 0.3 parts by weight, it is difficult to obtain an effective foaming rate, and even if an amount exceeding 10 parts by weight is added, the corresponding effect can not be obtained and the foaming efficiency is poor. It is uneconomical.

  The acrylic processing aid used in the present invention is not particularly limited as long as it is an acrylic processing aid generally used for producing polyvinyl chloride resin molded articles. Specifically, for example, polymethyl methacrylate or a polymethyl methacrylate resin such as a copolymer of methyl methacrylate as a main component and ethyl acrylate, acrylonitrile, styrene or the like may be mentioned. Acrylic processing aids are generally those having a weight average molecular weight of greater than 2.5 million.

  By adding an acrylic processing aid to the vinyl chloride resin composition, the foam cells are dispersed uniformly, the heat insulation of the refrigerator door gasket is improved, and the tensile strength and the elongation rate are increased. The properties are improved, and the smoothness of the refrigerator door gasket surface is improved.

  The proportion of the above acrylic processing aid is 1 to 20 parts by weight, preferably 2 to 10 parts by weight, and more preferably 2.4 to 5.5 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

  A modifier, a stabilizer, a lubricant, an antifungal antibacterial agent, a pigment and the like may be appropriately added to the vinyl chloride resin composition of the present invention as needed to maintain hygiene and beauty and the like. it can.

  The refrigerator door gasket of the present invention is manufactured by extrusion molding a foamed vinyl chloride resin composition. Extrusion is carried out by melting and foaming at 130 to 170 ° C. with an extruder such as a single screw extruder or a twin screw extruder according to a conventional method, for example, passing a mold having a shape corresponding to the cross sectional shape shown in FIG. . Thereafter, the extruded molding is cooled to obtain the refrigerator door gasket of the present invention.

  The refrigerator door gasket of the present invention preferably has a foaming rate of 5 to 60%. If the foaming rate exceeds 60%, defects in the welding process are likely to occur, and communicating air bubbles are generated to deteriorate the thermal conductivity of the refrigerator door gasket. 10 to 50% is preferable and, as for the foaming rate of a refrigerator door gasket, 15 to 45% is more preferable.

  The refrigerator door gasket of the present invention preferably has a Shore A hardness of 60A to 75A. If the Shore A hardness is less than 60 A, the adhesion is low, burrs and warps are easily generated during molding, and the hardness is soft, so it is not suitable as an external part of a refrigerator because it is easily damaged by external force. It was not used. If the Shore A hardness exceeds 75 A, the door opening / closing force becomes low, which may cause sealing failure and heat leakage may increase. The Shore A hardness of the refrigerator door gasket is preferably 60A to 75A, and more preferably 65A to 73A.

  The refrigerator door gasket of the present invention is excellent in heat insulation, and excellent in strength and durability, and as a result of a durability test in which the refrigerator door is opened and closed 50,000 times or more, problems occur in the attachment portion, release force and holding force. do not do.

  Hereinafter, the present invention will be described based on examples, but is not limited thereby without departing from the scope of the invention.

<Manufacture of refrigerator door gasket>
The following materials were prepared as components of the foamable vinyl chloride resin composition.

[Table 1]

  The material is charged into an extruder, melted under the conditions of Table 2, passed through a mold having a shape corresponding to the cross-sectional shape shown in FIG. 1, and then the extruded product is cooled to obtain the refrigerator of the present invention. I got a door gasket.

  FIG. 2 is an enlarged photograph showing a cross section of the refrigerator door gasket of the present invention. Referring to FIG. 2, the closed cell bubble structure is confirmed except near the surface. FIG. 3 is an enlarged photograph showing a cross section of a conventional refrigerator door gasket. Referring to FIG. 3, it can be confirmed that air bubbles are substantially absent.

[Table 2]
Extruder: "φ75 single screw extruder" manufactured by Aoshima Kiki Co., Ltd. L / D = 25

Gasket extrusion molding operation:
First step: Charge and melt PVC for foaming into an extruder;
Second step: passing the mold and extruding the molding;
Third step: passing the extrudate through a mold for cooling and controlling foaming;
Fourth step: 45 ° square cut;
Fifth step: welding

  Then, the operation described below was performed to measure the performance of the obtained refrigerator door gasket. The blend ratio (parts by weight) of each material and the measurement results are shown in Table 2.

<Performance test>
1. Shore A Hardness Shore A hardness was measured in accordance with JIS K6253.

2. The foaming rate was calculated by the following formula.

  Foaming ratio (%) = (non-foamed ratio product specific gravity / foamed product specific gravity-1) × 100%

3. Heat leak amount A refrigerator door of a refrigerator "AQUA AQR-361E" (trade name) manufactured by Haier Asia Ltd. was prepared. Kind of refrigerator door is for cold storage (length 790 mm, width 600 mm, thickness 7 mm, cold storage capacity 197 liters, storage temperature 5 ° C), for vegetables room (long 440 mm, width 600 mm, thickness 7 mm, vegetables room capacity 69 liters There were three types: internal temperature 5 ° C.) and for the freezer (longitudinal length 440 mm, width 600 mm, thickness 7 mm, freezer volume 89 liters, interior temperature -18 ° C.).

  The gasket and the auxiliary packing on the inner periphery of the gasket were removed from the inner panel of the refrigerator door.

  The obtained refrigerator door was attached to the main body, and the heat leak amount (WH / h) of the refrigerator was measured. The measurement conditions and method of the heat leak amount are as follows.

  Heaters were installed in the refrigerator compartment, the vegetable compartment and the freezer compartment of the refrigerator. The heater device has a temperature control function of turning on and off the switch in accordance with the change of the ambient temperature so as to maintain the temperature in the partial chamber at the set temperature. Then, the refrigerator door was closed and the refrigerator was put into a temperature-controlled room.

  The temperature inside the temperature-controlled room was adjusted to -24 ° C. The temperature in the refrigerator (refrigerated compartment, freezer compartment and vegetable compartment) was adjusted to 10 ° C. After that, the temperature of the temperature-controlled room was maintained for 2 hours. In the meantime, when the heat in the refrigerator room leaks to the temperature-controlled room and the temperature in the room decreases, the heater device is turned on.

  The amount of power consumed (WH) was integrated by turning on the heater, and the values of the cold room, the freezer and the vegetable room were summed to obtain the heat leak amount (WH) in one refrigerator.

  The temperature in the refrigerator was adjusted to 16 ° C., 22 ° C. and 28 ° C., the same operation was performed at each temperature, and the heat leak amount (WH) of one refrigerator at each temperature condition was recorded.

  The heat leak amount (WH) of one refrigerator was recorded in the same manner as described above except that the temperature of the constant temperature room and the temperature in the refrigerator were changed as follows.

[Table 3]

4. Durability Conducted door opening and closing endurance test up to 50000 times. We measured the failure of each part, the amount of lowering the door, and the door opening power, and confirmed that there was no problem in practical use.

5. Appearance Visual inspection was performed. It was confirmed that there were no defects that would cause practical problems such as gasket breakage.

[Table 4]

1 ... refrigerator door,
2 ... refrigerator door gasket,
3 ... refrigerator body storage room,
4 ... rim,
5 ... Groove for attaching refrigerator door gasket,
6 ... opening edge,
7 ····· Attached to peripheral edge,
8 ... Magnet holding unit,
9 ... bag-like part,
10 ... arrow-like locking portion.

Claims (7)

  A thin bag-like portion that telescopically connects the mounting portion to the peripheral portion of the refrigerator door, a magnet holding portion storing a magnet to be attracted to the opening peripheral portion of the refrigerator main body storage room, and the mounting portion and the magnet holding portion A refrigerator door gasket comprising a foam of a foamable vinyl chloride resin composition.   The refrigerator door gasket according to claim 1, wherein the foam has a closed cell structure.   The refrigerator door gasket according to claim 1, wherein the foam has a foam rate of 15 to 45%.   The refrigerator door gasket according to any one of claims 1 to 3, wherein the foam has a Shore A hardness of 60A to 75A.   The foamable vinyl chloride resin composition comprises 100 parts by weight of a vinyl chloride resin, 50 to 85 parts by weight of a plasticizer, 40 to 80 parts by weight of an inorganic filler, 1.3 to 3 parts by weight of a foaming agent, and an acrylic processing aid 2 The refrigerator door gasket according to any one of claims 1 to 4, which contains 4 to 5.5 parts by weight.   The refrigerator door which has a refrigerator door gasket as described in any one of Claims 1-5.   The refrigerator which has a refrigerator door of Claim 6.