KR101388194B1 - Composition for an refrigerator gasket - Google Patents

Abstract

Provided is a refrigerator gasket composition comprising a mixture of an olefin/alpha-olefin copolymer (OAO) having a melting point of 100 °C or higher and a styrene block copolymer (SBC) as a polymer substrate and having a melt index (190 °C, 5 kg) of the polymer substrate of 0.01-15 g per ten minutes.

Description

Composition for an refrigerator gasket

The technology disclosed herein relates to a composition for a refrigerator gasket.

Currently, the refrigerator gasket is profile extrusion of a composition including additives such as fillers and stabilizers in a soft vinyl chloride resin (PVC), and at this time, the rubber is mixed with a ferrite inside the gasket to extrude and magnetize. It is made by inserting the rubber strip of the made strip shape and heat-sealed to a predetermined length.

The vinyl chloride resin may generate dioxin upon incineration, and the plasticizer used to process the vinyl chloride resin has a problem when used in a product having high contact potential with food as an environmental hormone component. Therefore, Korean Patent Publication No. 2003-0042229 and Japanese Laid-Open Patent Publication No. 2000-017142 have been trying to substitute other materials for the manufacture of refrigerator gaskets instead of vinyl chloride.

However, in the case of other resins except vinyl chloride resin, release extrusion is difficult, elasticity is not maintained for a long time, and there are problems such as insufficient durability and surface adhesiveness, which makes it difficult to replace vinyl chloride resin in the refrigerator gasket field.

On the other hand, according to the present inventors Patent No. 10-1263701 using an olefin block copolymer (OBC) and a thermoplastic polyurethane (TPU), the performance as a general refrigerator gasket is satisfactory, but there is a phenomenon that the TPU is discolored by UV, for a long time Because of its discoloration, it is difficult to use in appearance, and there is a hydrolysis phenomenon, so that a large amount of TPU cannot be used, and the amount of use is limited, so that there is a limit in improving the elasticity, which is an improvement target of the patent.

According to one aspect of the technology disclosed herein, a polymer substrate comprises a mixture of an olefin / α-olefin copolymer (OAO) having a melting point of at least 100 ° C., and a styrene block copolymer (SBC), wherein the polymer substrate is melted. A composition for refrigerator gaskets having an index (190 ° C., 5 kg) of 0.01 to 15 g / 10 min is provided.

According to another aspect of the technology disclosed herein, a mixture of an olefin random copolymer (ORC), an olefin block copolymer (OBC) and a styrene block copolymer (SBC) as a polymer substrate, wherein the melt index ( 190 ° C., 5 kg) is provided for a refrigerator gasket composition having 0.01 to 15 g / 10 min.

According to another aspect of the technology disclosed herein, a mixture of an olefin / α-olefin copolymer (OAO), and a styrene block copolymer (SBC) as a polymer substrate, wherein the melt index (190 ℃, 5 kg) is provided with a refrigerator gasket having 0.01 to 15 g / 10 minutes and a Shore A hardness of 60 to 80.

Hereinafter, the technique disclosed in the present specification will be described in more detail.

As described above, it is possible to release extrusion as a gasket material of the refrigerator and have a hardness of Shore A 60 to 80. As a soft material, it is difficult to find an alternative material except PVC. Soft materials for use in refrigerator gaskets include, for example, ethylene copolymers such as EVA, EMA, EBA, POE, and thermoplastic rubbers such as SBC (for example, SBS, SEBS, SEPS, etc.), 12-PB, TPU, TPEE Etc. are used, the following difficulties exist. Among them, Shore A 60 to 80 material with low melting point is difficult to extruding due to the product is warped due to the slow rate of solidification after exiting the die during extrusion. On the other hand, when a material capable of extruding due to its high melting point is used, the hardness is too high, so that softeners such as process oils for reducing the hardness are mixed. At this time, the elastic loss of the product due to the softener and the softener leak out to the surface of the product and the product becomes sticky, and the adhesiveness is deteriorated when the corner is melt-bonded. Many side effects were difficult to commercialize.

Therefore, according to the technology disclosed herein, a novel composition for a refrigerator gasket is provided. The composition for a refrigerator gasket disclosed herein may include a mixture of an olefin / α-olefin copolymer (OAO) and a styrene block copolymer (SBC) as a polymer substrate.

The melting point of the olefin / α-olefin copolymer is at least 100 ° C. or higher and the melt index (MI) (190 ° C. 5 kg) of the final mixed composition is from 0.01 to 15.0 g / 10 min, suitable for refrigerator gaskets.

The term "olefin / alpha-olefin copolymer" as used herein generally refers to a polymer comprising ethylene or propylene and alpha-olefins having two or more carbon atoms. The? -Olefin is an olefin having 2 or more carbon atoms and having a double bond at the terminal.

Preferably, ethylene or propylene accounts for the major mole fraction of the total polymer, i.e., ethylene or propylene accounts for at least about 50 mole percent of the total polymer. More preferably, the ethylene or propylene occupies at least about 60 mol%, at least about 70 mol%, or at least about 80 mol%, and the substantial remainder of the total polymer is preferably an alpha -olefin having at least three carbon atoms One or more other comonomers. For example, in the case of an ethylene / octene copolymer, the preferred composition comprises an ethylene content of at least about 80 mole percent of the total polymer, and an octene content of from about 10 to about 15 mole percent, preferably from about 15 to about 20 mole percent, .

The olefin /? - olefin copolymer may be a random copolymer or a block copolymer. Examples of OAO are Ethylene Alpha Olefin (EAO) or Propylene Alpha Olefin (PAO), and many products are commercially available. EAO includes Dow Chemical's Engage and Infuse, Mitsui's Tafmer, Exxon Mobile Exact, LG Chem's LG -POE, etc. PAOs include Dow Chemical's Versify, Mitsui's Notio, and Exxon Mobile's Vistamaxx. In most cases, they have a low melting point and cannot be used for release extrusion. Extrusion is possible when the melting point is 100 ° C or higher. However, most of these extruded OAOs have high hardness and are difficult to use as refrigerator gaskets. Therefore, it is necessary to blend other materials to satisfy the low hardness and viscosity of the molten resin required for release extrusion for use in refrigerator gaskets. In addition, in order for the OAO to be used in the refrigerator gasket, it is preferable that the airtightness of the gasket is maintained even after opening and closing operations of tens of thousands to several hundred thousand times. This requires considerable high elasticity. Therefore, in order to simultaneously solve the three requirements of low hardness, high elasticity and high viscosity during extrusion, and also to solve the melt adhesion, the inventors have completed the invention by using a styrene block copolymer (SBC).

This SBC also has a melt index (MI, 190 ° C, 2.16kg) of 5.0g / 10 minutes or more, so that the final MI is too high when blended with the OAO, so that it is difficult to use because it is not extruded, and MI (190 ° C, 2.16kg) is difficult to use. ) May be less than 5.0 g / 10 minutes, preferably less than 2.0 g / 10 minutes.

In order to improve the workability of the final mixture, a lubricant such as stearic acid, ethylene bis stearamide, or a mixture of silica (SiO ₂ ) is used to further lower the MI of the mixture or to increase the viscosity. Fillers such as, MgCO ₃ , CaCO ₃ , Talc, Al (OH) ₃ , Mg (OH) _2, and the like.

In addition to OAO and SBC, the polymer substrate may further include an ethylene copolymer (for example, EVA, EEA, EMA, EBA, ENMMA, POE, etc.) or a thermoplastic rubber (for example, 12-PB, TPU, TPEE, TPV, CPE, etc.). May be included.

The MI (190 ° C 5 kg) of the final mixed composition is preferably 0.01 to 15.0 g / 10 minutes, preferably 1.0 to 10.0 g / 10 minutes, more preferably 1.0 to 7.0 g / 10 minutes. If the MI (190 ℃, 5kg) of the final mixed composition is less than 0.01g / 10 minutes extruded too high pressure on the extruder high risk of damage to the machine and the extrusion amount is so small that it takes too long time to produce the desired product If the MI (190 ℃ 5kg) is more than 15g / 10 minutes, the viscosity of the mixture exiting the die of the extruder is low, the product is warped, the desired shape can not be obtained.

The use ratio of OAO to SBC is 10:90 to 90:10 by weight, preferably 15:85 to 85:15, more preferably 20:80 to 80:20, even more preferably 30:70 to 70: 30 is good. If the OAO is less than 10 and the SBC is more than 90, the surface of the product is sticky and the cooling is slow during corner bonding. It is lacking in shape and can be deformed in long term use.

In one embodiment, the olefin / α-olefin copolymer used in the composition for refrigerator gaskets is an olefin random copolymer (ORC).

The olefin random copolymer may be a form in which ethylene or propylene and one or more copolymerizable α-olefin comonomers are randomly polymerized.

When the ORC is a copolymer of ethylene and an? -Olefin, that is, an EAO, it may contain at least one copolymer of, for example, a C3-C20? -Olefin, a C3-C12? -Olefin or a C3-C8? -Olefin. Suitable alpha-olefins can be linear or branched (e.g., one or more C1-C3 alkyl branched chain or aryl groups). Specific examples are propene, butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, pentene, pentene having at least one methyl, ethyl or propyl substituent, hexene having at least one methyl, ethyl or propyl substituent Heptene having at least one methyl, ethyl or propyl substituent, octene having at least one methyl, ethyl or propyl substituent, nonenes having at least one methyl, ethyl or propyl substituent, ethyl, methyl or dimethyl substituted decene, . Particularly desired alpha-olefin comonomers are propylene, butene (e.g. 1-butene), hexene and octene (e.g. 1-octene or 2-octene). The ethylene content of such copolymers may be from about 60 mole percent to about 99.5 mole percent, in some embodiments from about 80 mole percent to about 99 mole percent, and in some embodiments from about 85 mole percent to about 98 mole percent. Likewise, the α-olefin content may range from about 0.5 mol% to about 40 mol%, in some embodiments from about 1 mol% to about 20 mol%, and in some embodiments, from about 2 mol% to about 15 mol%. The distribution of α-olefin comonomers is typically random and uniform over different molecular weight fractions forming ethylene copolymers.

When the ORC is a copolymer of propylene and an alpha -olefin, i.e., PAO, it may contain at least one copolymer of, for example, a C2-C20 alpha-olefin, a C2-C12 alpha-olefin, or a C2-C8 alpha-olefin. Suitable alpha-olefins can be linear or branched (e.g., one or more C1-C3 alkyl branched chain or aryl groups). Specific examples are ethylene, butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, pentene, pentene having at least one methyl, ethyl or propyl substituent, hexene having at least one methyl, Heptene having at least one methyl, ethyl or propyl substituent, octene having at least one methyl, ethyl or propyl substituent, nonenes having at least one methyl, ethyl or propyl substituent, ethyl, methyl or dimethyl substituted decene, . Especially desirable alpha-olefin comonomers are ethylene, butene (e.g., 1-butene), hexene and octene (e.g., 1-octene or 2-octene). The propylene content of such copolymers may be from about 60 mol% to about 99.5 mol%, in some embodiments from about 80 mol% to about 99 mol%, and in some embodiments from about 85 mol% to about 98 mol%. Likewise, the α-olefin content may range from about 0.5 mol% to about 40 mol%, in some embodiments from about 1 mol% to about 20 mol%, and in some embodiments, from about 2 mol% to about 15 mol%. The distribution of the -olefin comonomers is typically random and uniform over different molecular weight fractions forming the propylene copolymer.

The density of the ethylene /? - olefin copolymer (EAO) or propylene /? - olefin copolymer (PAO) may be a function of the length and amount of? -Olefins. That is, the longer the length of the -olefin and the larger the amount of the -olefin, the lower the density of the copolymer. Generally speaking, the higher the density of the copolymer, the better retain the three-dimensional structure and the lower the density of the copolymer, the better the elastomeric properties can be.

The ORC is chosen to have a density of 0.86 to 0.90 g / cc, in some embodiments about 0.861 to about 0.89 g / cc, and in some embodiments about 0.862 to about 0.88 g / cc.

In one embodiment, the olefin / α-olefin copolymer used in the composition for refrigerator gaskets is an olefin block copolymer (OBC).

The olefin block copolymer (OBC) is a multi-block copolymer. These are preferably polymers comprising two or more chemically distinct zones or segments (referred to as "blocks ") joined in a linear fashion, i.e. polymers which are polymerized rather than pendant or grafted, such as ethylene- or propylene- Lt; RTI ID = 0.0 > chemically < / RTI >

The olefin block copolymer (OBC) means an ethylene /? - olefin multiblock copolymer or a propylene /? - olefin multiblock copolymer. Wherein the olefin block copolymer comprises ethylene or propylene in the form of polymerizing at least one copolymerizable alpha -olefin comonomer and having a plurality of blocks or segments of two or more polymerized monomer units differing in chemical or physical properties, Chain. The content of olefin and? -Olefin in the OBC is the same as described for the ORC.

In some embodiments, the multi-block copolymer can be represented by the following formula:

(AB) n

N is an integer greater than or equal to 1, preferably greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, ; "A" represents a hard block or segment; "B" represents a soft block or segment. Preferably, A and B are connected in a linear manner, not in a branched or star manner. By "hard" segment is meant a block of polymerized units in which ethylene or propylene is present in an amount of at least 95 weight percent, in some embodiments at least 98 weight percent, in some embodiments. That is, the comonomer content in the hard segment is, in some embodiments, 5 wt% or less, and in other embodiments, 2 wt% or less of the total weight of the hard segment. In some embodiments, the rigid segments consist of all or substantially all of ethylene or propylene. By contrast, a "soft" segment is a segment of polymerized units wherein the comonomer content is at least 5 wt%, in various embodiments greater than or equal to 8 wt%, at least 10 wt%, or at least 15 wt% of the total weight of the soft segment in some embodiments Block. In some embodiments, the comonomer content in the soft segment is greater than or equal to 20 wt%, greater than 25 wt%, greater than 30 wt%, greater than 35 wt%, greater than 40 wt%, greater than 45 wt%, greater than 50 wt% Or more, or 60 wt% or more.

In one embodiment, the olefin block copolymer may have a density of 0.85 to 0.91 g / cc, or 0.86 to 0.88 g / cc.

In one embodiment, the olefin block copolymer has a melt index (MI) as measured by ASTM D1238 (190 ° C., 2.16 kg) of 0.01 to 30 g / 10 minutes, or 0.01 to 20 g / 10 minutes, or 0.1 to 10 g / 10 minutes, or 0.1 to 5.0 g / 10 minutes, or 0.1 to 1.0 g / 10 minutes, or 0.3 to 0.6 g / 10 minutes.

According to the composition for refrigerator gaskets disclosed herein, a styrene block copolymer (SBC) is blended with an olefin / α-olefin copolymer (OAO). Refrigerator gaskets in which the polymer base component is OAO alone may have low elasticity. Therefore, the composition for a refrigerator gasket simultaneously contains a styrene block copolymer component.

In a preferred embodiment, when the styrene block copolymer (SBC) is blended with the olefin / α-olefin copolymer (OAO), an olefin random copolymer (ORC) and an olefin block copolymer (OBC) can be used simultaneously as the OAO. Can be. At this time, when ORC alone and SBC are mixed, the melting point (mp) of ORC may be low, so that extrusion workability may be deteriorated, and the compression set of ORC may be low, resulting in poor shape retention. It may take time to cool down, which may reduce productivity. On the other hand, OBC alone and SBC may be mixed, but the OBC's elasticity is slightly low, the cold storage capacity of the refrigerator is somewhat lowered, the amount of electricity may be increased. In addition, the melting point (mp) is too high may take too long heating time when bonding corners may reduce the adhesive productivity. As a result, the best results can be obtained when combining ORC and OBC and mixing SBC.

When the olefin random copolymer (ORC) and the olefin random copolymer (OBC) are used together as the olefin / α-olefin copolymer, the weight of the olefin random copolymer is A1, and the weight of the olefin block copolymer is A2, When the weight of the styrene block copolymer is A3, the weight ratio of (A1 + A2): A3 may be 1: 4 to 9: 1, and the weight ratio of A1: A2 may be 1: 0.5 to 1: 6. . Preferably the weight ratio of A1: A2 may be 1: 0.8 to 1: 5.5, more preferably 1: 1 to 1: 5. If the ratio of OBC to the ORC in the weight ratio range is too small, extrusion workability or shape retention may be poor, and if the ratio of OBC is too large, the elasticity may be insufficient. In addition, if the ratio of SBC in the total olefin / α-olefin copolymer is too small, extrusion workability or shape retention may be poor, too large may reduce extrusion workability and corner adhesiveness.

The styrene block copolymer is styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butadiene-styrene block copolymer (SEBS), styrene-butylene-butadiene It may include one or more selected from the group consisting of styrene block copolymer (SBBS) and styrene-ethylene-propylene-styrene block copolymer (SEPS). More specific examples of such styrene block copolymers are described in EP 0 712 892 B1, WO 2004/041538 A1, USP 6,582,829 B1, US 2004/0087235 A1, US 2004/0122408 A1, US 2004/0122409 A1, and USP 4,789,699, 5,093,422 and 5,332,613.

The styrene block copolymer comprises at least two mono-alkenyl arene blocks, preferably two blocks of saturated conjugated dienes, preferably saturated polybutadiene blocks, having a residual ethylenic unsaturation of less than 20%. It may have a polystyrene block. In some embodiments branched or radial polymers or functionalized block copolymers are useful compounds, but preferred styrene block copolymers have a linear structure.

The total number average molecular weight of the styrene block copolymer is preferably 30,000 to 250,000 when the copolymer has a linear structure. Such block copolymers generally have an average polystyrene content of 10% to 65% by weight, more generally 10% to 40% by weight.

SEBS (S is styrene, E is ethylene, B is butylene) and SEPS (P is propylene) block copolymers useful in certain embodiments are available from Kraton Polymers, Asahi Kasei and Kuraray America.

The composition for a refrigerator gasket may include, for example, an ethylene-octene block copolymer and a styrene-ethylene-butylene-styrene block copolymer as a polymer substrate.

The refrigerator gasket may be manufactured by release extrusion of the composition for a refrigerator gasket disclosed herein. Refrigerator gasket manufactured using the composition for a refrigerator gasket disclosed in the present disclosure has an advantage of excellent extrusion workability, excellent elasticity, excellent corner adhesiveness, and no surface stickiness.

According to one embodiment, a mixture of an olefin / α-olefin copolymer (OAO) and a styrene block copolymer (SBC) is included as a polymer substrate, and the melt index of the polymer substrate (190 ° C., 5 kg) is 0.01 to 15 g. A refrigerator gasket is provided for / 10 minutes and a Shore A hardness of 60 to 80.

At this time, the olefin / α-olefin copolymer is preferably a melting point of 100 ℃ or more. As a preferred example, the olefin / α-olefin copolymer may be a copolymer of ethylene or propylene and octene.

A magnet may be included in the body of the refrigerator gasket. Preferably a rubber magnet may be included. The rubber magnet may be a strip made by extruding and magnetizing a mixture of magnetic powder and rubber. The magnet may facilitate the sealing of the refrigerator door.

The weight ratio of the olefin / α-olefin copolymer to the styrene block copolymer is 10:90 to 90:10, preferably 15:85 to 85:15, more preferably in order to secure proper physical properties such as elasticity and corner adhesion. 20:80 to 80:20, even more preferably 30:70 to 70:30.

Hereinafter, the technology disclosed herein will be described in more detail with reference to examples, but the spirit of the disclosed technology is not limited by the present embodiment.

<Examples>

EAO-1: Ethylene-Octene Random Copolymer (Dow Engage), Density: 0.885g / cc, Melting Point: 77 ℃

EAO-2: Ethylene-Octene Random Copolymer (Dow Engage), Density: 0.908g / cc, Melting Point: 104 ℃

EAO-3: Ethylene-Octene Block Copolymer (Dow Infuse), Density: 0.877g / cc, Melting Point: 122 ℃

EAO-4: Ethylene-Octene Random Copolymer (Dow Engage), Density: 0.865g / cc, Melting Point: 55 ℃

PAO-1: Propylene-Octene Random Copolymer (Dow Versify), Density: 0.865g / cc, Melting Point: 55 ℃

PAO-2: Propylene-Alphaolefin Random Copolymer (Mitsui Notio), Density: 0.866g / cc, Melting Point: 135 ℃

EVA-1: Ethylene Vinylacetate (VA content: 26%, MI: 2.5), Melting point: 71 ° C

SBC-1: Styrene Ethylene Buthylene Styrene (Styrene content, 30% MI (190 ℃, 2.16kg): 6.0)

SBC-2: Styrene Ethylene Butylene Styrene (Styrene content, 30% MI (190 ℃, 2.16kg): 0.2)

SBC-3: Styrene Ethylene Butylene Styrene (Styrene Content: 30%, MI (230 ℃, 2.16kg): 6.0)

TPU-1: Ester based TPU (Ester based TPU, Dongsung Hichem Grade 5080A)

EVA-1: Ethylene Vinylacetate (VA 26%, MI (190 ° C, 2.16 kg): 2.5)

(Performance evaluation)

1) Extrusion workability: After adjusting the cylinder temperature to 170 ° C. in an extruder in which a cylinder diameter of 100 mm and an L / D of 36: 1 are combined with a die of a refrigerator gasket shape, extrude the mixtures of Comparative Examples and Examples. Immediately after the extrudate comes out through the die, it passes through a chamber equipped with a freezer (set at a temperature of 100 ℃ and a pass time of 20 seconds) to obtain the desired shape and comprehensively judge the extrudeability.

2) Surface stickiness: touch test

3) Elasticity: The mixture was placed in a mold having a thickness of 2 mm, heated under pressure at 200 ° C. for 5 minutes, and cooled in a cold press for 5 minutes to obtain a mixture specimen having a thickness of 2 mm. Cut the mixture specimen into 2mm width and 100mm length, tape both ends of the specimen and make it round, leave it for 10 minutes, cut the tape, measure the time for the specimen to return to its original straight shape, and make it short. Ranked A, B, C, D, and E.

4) Shape maintainability: Cut the 2mm thick specimen into 10mm wide and 100mm long, hang it on a Demattia flexure tester, perform 200,000 bends, and change the shape according to the degree of deformation of the original specimen (planar). Numbered B, C, D, E.

5) Corner adhesiveness: Make the specimens 5mm thick and 100mm long, and contact the two specimens with both surfaces of the double-sided heater with a temperature of 250 ℃ to melt the surface, remove the heaters, and stick the specimens together for 1 second, 2 seconds, 3 After a second, 4, and 5 seconds, the A, B, C, D, and E were graded according to the degree of fastening of the adhesive.

6) Surface smoothness: The surface of the sample obtained through the extrusion workability test was visually observed, and A, B, C, D, and E were graded according to the goodness of the surface state.

7) Hydrolyzability (Promoting Test): After submerging the specimen of thickness 2mm in water at 50 ℃ for 7 days, take it out and dry it at 50 ℃ for 5 hours, measure the tensile strength of each specimen and measure the tensile strength of the original specimen. When the strength decreases within 5.0%, A, 5.1-10.0% B, 10.1-15.0% C, 15.1-20.0% D, and 20.1-25% E are indicated.

8) UV discolorability: A to E was indicated according to the color change after 8 hours using a C type UV lamp.

The results are shown in Table 1 below.

[Table 1]

A: Excellent, B: Excellent, C: Normal, D: Poor, E: Poor

Referring to Table 1, as described in Examples 1 to 13, a refrigerator gasket manufactured by release extrusion of a composition for a refrigerator gasket using OAO and SBC simultaneously as a polymer substrate has excellent compression workability, but has surface characteristics, shape retention, It has excellent corner adhesiveness and has very suitable properties as a gasket. On the other hand, even when the blend of OAO and SBC is used as a polymer substrate, only the melting point of less than 100 ℃ OAO is used, and the melt index (190 ℃, 5kg) is more than 15g / 10 minutes it can be seen that the extrusion workability is poor.

It can be seen that when the ORC and OBC are used together as the OAC as in Examples 10 to 13, the elasticity is excellent.

In addition, the refrigerator gasket made of this material does not cause hydrolysis due to contact of moisture by food in the refrigerator, and when used in a refrigerator equipped with an ultraviolet sterilizer, yellowing due to ultraviolet rays (UV) does not occur, thus resulting in elasticity and shape retention. Has the advantage of having.

From the above, various embodiments of the disclosed technology have been described for the purposes of illustration, and it will be understood that there are various possible variations without departing from the scope and spirit of the disclosed technology. And, the various embodiments disclosed are not intended to limit the spirit of the disclosed technology, and the true spirit and scope will be set forth in the claims below.

Claims (15)

delete delete delete delete delete delete delete As a polymer substrate, a mixture of an olefin random copolymer (ORC), an olefin block copolymer (OBC) and a styrene block copolymer (SBC),
The olefin random copolymer and the olefin block copolymer each have a structure of an olefin / α-olefin copolymer, and the olefin / α-olefin copolymer is composed of ethylene or propylene and an α-olefin having 3 or more carbon atoms. Copolymer,
Melting index (190 ℃, 5kg) of the polymer substrate is a composition for refrigerator gaskets of 0.01 to 15g / 10 minutes. As a polymer substrate, a mixture of an olefin random copolymer (ORC), an olefin block copolymer (OBC) and a styrene block copolymer (SBC),
Melt index (190 ℃, 5kg) of the polymer substrate is 0.01 to 15g / 10 minutes,
When the weight of the olefin random copolymer is A1, the weight of the olefin block copolymer is A2, and the weight of the styrene block copolymer is A3, the weight ratio of (A1 + A2): A3 is 1: 4 to 9: 1, wherein the weight ratio of A1: A2 is 1: 0.5 to 1: 6. 10. The method according to claim 8 or 9,
Refrigerator gasket composition further comprises an ethylene copolymer or a thermoplastic rubber in the polymer substrate. Olefin / α-olefin copolymer (OAO), and a mixture of styrene block copolymer (SBC) as a polymer substrate,
The olefin / α-olefin copolymer is a mixture of an olefin random copolymer and an olefin block copolymer, a melt index (190 ° C., 5 kg) of the polymer substrate is 0.01 to 15 g / 10 min, and Shore A hardness is 60 to 80 And a refrigerator gasket including a magnet therein. 12. The method of claim 11,
And a weight ratio of the olefin / α-olefin copolymer to the styrene block copolymer is 10:90 to 90:10. 12. The method of claim 11,
The olefin is ethylene or propylene, wherein the α-olefin is a olefin having 3 or more carbon atoms having a double bond in the refrigerator. 12. The method of claim 11,
The olefin / α-olefin copolymer is a refrigerator gasket is a copolymer of ethylene or propylene and octene. 15. The method according to any one of claims 11 to 14,
When the weight of the olefin random copolymer is A1, the weight of the olefin block copolymer is A2, and the weight of the styrene block copolymer is A3, the weight ratio of (A1 + A2): A3 is 1: 4 to 9: 1, wherein the weight ratio of A1: A2 is 1: 0.5 to 1: 6.