KR20230142032A - Gasket rubber composition and heat-expandable flame retardant gasket by using the same - Google Patents

Abstract

The present invention relates to a rubber composition for a gasket and a flame-retardant expansion gasket using the same. More specifically, the present invention relates to a rubber composition for a gasket of a specific composition, which contains thermally expandable graphite that significantly expands and foams in volume above a predetermined temperature, thereby preventing fire. Even if a fire occurs, the gasket itself not only does not burn and does not generate toxic gases, but also prevents the spread of flames and harmful gases in the event of a fire and exhibits excellent airtightness, so it can continuously demonstrate high flame retardancy.

Description

Rubber composition for gaskets and flame retardant expansion gasket using the same {GASKET RUBBER COMPOSITION AND HEAT-EXPANDABLE FLAME RETARDANT GASKET BY USING THE SAME}

The present invention relates to a rubber composition for gaskets and a flame-retardant expansion gasket using the same, and more specifically, to a rubber composition containing ethylene-propylene-diene-based rubber, neoprene-based rubber, chlorinated polyolefin-based resin and flame retardant in a specific composition, It relates to a thermally expandable flame retardant gasket that ensures high flame retardancy and environmental friendliness by preventing the spread of flames and harmful gases in the event of a fire by providing expanded graphite whose volume expands significantly when the temperature rises above a predetermined temperature.

Fire door gaskets used in buildings are placed in fire doors, sashes, windows, and/or glass gaps to prevent water leaks, soundproofing, and windbreaks. These gaskets are mainly made of synthetic rubber, polyvinyl chloride (PVC), or Ethylene-Propylene-Diene Monomer (EPDM)-based rubber. In particular, EPDM-based materials (especially black) are used for approximately 90%. It is used more than %.

Meanwhile, when a fire occurs in a building, the gasket also ignites, and in the case of conventional rubber gaskets, it generates halogen-based toxic gas that is toxic to the human body and can cause serious damage to people inside the building. In addition, when the gasket cannot withstand the heat caused by the fire and disappears, a gap is created. This gap opens the path of the flame and spreads the flame to surrounding buildings, causing secondary damage.

Gaskets developed to date mainly use EPDM, a general rubber material. However, EPDM rubber is vulnerable to fire due to its dielectric properties, so using a gasket made of EPDM rubber may cause serious safety problems in the event of a fire. Nevertheless, non-flame retardant rubber gaskets are being used in all construction areas.

The present invention was developed to solve the problems of the prior art described above. The gasket itself is non-combustible even in the event of a fire, and when a fire occurs, when exposed to flame or heat, it expands significantly and foams to fill the gap. The technical task is to provide an eco-friendly rubber composition for gaskets that can continuously maintain excellent durability and airtightness by preventing the spread of flame and heat.

Another technical problem of the present invention is to provide a heat-expandable, flame-retardant, flame-tight gasket manufactured using the above-described rubber composition for gaskets.

Other objects and advantages of the present invention can be more clearly explained by the following detailed description and claims.

In order to achieve the above-mentioned technical problem, the present invention is an ethylene-propylene-diene (EPDM)-based rubber; Neoprene-based rubber; Chlorinated polyolefin resin; inorganic filler; flame retardants; and process oil, and provides a rubber composition for a gasket including 5 to 15 parts by weight of expanded graphite based on 100 parts by weight of the composition.

For example, the expanded graphite expands 100 to 300 times when heated to 150°C or higher, and may have a particle size of 60 to 300 mesh and a carbon component of 95% by weight or more. there is.

For one embodiment of the present invention, the ethylene-propylene-diene (EPDM)-based rubber includes at least three types, including an oil-free first ethylene-propylene-diene-based rubber; Non-oil-containing second ethylene-propylene-diene rubber; And it may include an oil-containing third ethylene-propylene-diene-based rubber.

For example, the first ethylene-propylene-diene rubber has a Mooney viscosity (ML1+4, 125°C) of 15 to 35 and an ENB (ethylidene norbornene) content of 4.5 to 4.5. 12% by weight, the ethylene content is 50 to 80% by weight, and the second ethylene-propylene-diene rubber has a Mooney viscosity (ML1+4, 125°C) of 45 to 65, The content of ethylidene norbornene (ENB) may be 4.5 to 12% by weight, and the content of ethylene may be 50 to 80% by weight.

For example, the third ethylene-propylene-diene rubber has a Mooney viscosity (ML1+4, 125°C) of 40 to 70 and an ENB (ethylidene norbornene) content of 3.0 to 3.0. It is 10% by weight, and the ethylene content may be 60 to 90% by weight.

For one embodiment of the present invention, the mixing ratio of the first ethylene-propylene-diene-based rubber, the second ethylene-propylene-diene-based rubber, and the third ethylene-propylene-diene-based rubber is 4 to 6: It may be a weight ratio of 0.3 to 2.5:3 to 5.

For one embodiment of the present invention, the neoprene rubber may have a Mooney Viscosity (ML1+4) of 35 to 55.

For one embodiment of the present invention, the chlorinated polyolefin-based resin may include at least one chlorinated polyethylene resin having a chlorination degree of 5 to 40% by weight.

For example, the inorganic filler includes calcium carbonate (CaCO ₃ ), talc, magnesium carbonate, clay, talc, barium sulfate, silica, mica, titanium oxide, carbon black, graphite, and carbon nanotubes. , graphite, wollastonite, and nanosilver.

For one embodiment of the present invention, the flame retardant may include a metal hydroxide-based first flame retardant; Antimony-based secondary flame retardant; Halogen-based third flame retardant; It may include at least one of:

For one embodiment of the present invention, the metal hydroxide-based first flame retardant may be at least one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, and potassium hydroxide.

For one embodiment of the present invention, the halogen-based third flame retardant may be at least one selected from the group consisting of decabromine and chlorinated paraffin.

For one embodiment of the present invention, the use ratio of the first flame retardant, the second flame retardant, and the third flame retardant may be 50 to 90: 3 to 20: 7 to 30 by weight.

For one embodiment of the present invention, the process oil may be at least one of paraffinic oil or naphthenic oil.

For one embodiment of the present invention, the composition includes 20 to 50 parts by weight of ethylene-propylene-diene (EPDM)-based rubber, based on 100 parts by weight of the composition; 1 to 15 parts by weight of neoprene-based rubber; 1 to 15 parts by weight of chlorinated polyolefin resin; 3 to 30 parts by weight of inorganic filler; 20 to 60 parts by weight of flame retardant; 5 to 15 parts by weight of expanded graphite; and 1 to 20 parts by weight of process oil.

For one embodiment of the present invention, the composition includes pigments, colorants, moisture absorbents, slip agents, antioxidants, lubricants, anti-aging agents, foaming agents, cross-linking agents, cross-linking aids, processing aids, vulcanizing agents, binders, coupling agents, heat stabilizers, And it may further include one or more additives selected from the group consisting of UV stabilizers.

In addition, the present invention provides a flame retardant expansion gasket using the above-described rubber composition for gaskets.

For one embodiment of the present invention, the flame retardant expansion gasket may be applied to at least one of fire doors, windows, chassis, and glass.

According to one embodiment of the present invention, a rubber composition for a gasket containing ethylene-propylene-diene-based rubber, neoprene-based rubber, chlorinated polyolefin-based resin, and flame retardant in a specific composition has a volume that significantly expands when the temperature rises above a predetermined temperature. By mixing thermally expandable expanded graphite, not only does the gasket itself not burn and generate no toxic gases even if a fire occurs, but it also prevents the spread of flames and harmful gases in the event of a fire, thereby realizing high flame retardancy and eco-friendliness. .

In addition, the present invention replaces conventional flame retardants containing substances hazardous to the human body (e.g., Pb, Cd, Hg, Cr, PBBs/PBDEs, etc.) with eco-friendly materials, thereby demonstrating high flame retardancy and at the same time complying with domestic environmental regulations and strengthening overseas regulations. All environmental standards can be met.

Furthermore, in the present invention, by sealing the gap between the window and glass sash of a general building using the above-described flame-retardant rubber gasket, not only does it block the spread of flames in the event of a fire by preventing air from entering from the outside, but also prevents the spread of flames in the event of a fire. By preventing smoke and smoke from escaping, it is possible to easily secure a time and place for people to evacuate.

The effects according to the present invention are not limited to the contents exemplified above, and more diverse effects are included in the present specification.

1 to 5 are flame retardancy evaluation test reports of the flame retardant expansion gasket specimen manufactured in Example 1 of the present invention, respectively.

Hereinafter, the present invention will be described in detail. However, it is not limited to the following content, and each component may be variously modified or selectively mixed as needed. Therefore, it should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

As used herein, the term “composition” includes reaction products and decomposition products formed from the materials of the composition, as well as mixtures of materials comprising the composition. As used herein, the term “polymer” also refers to a polymeric compound prepared by polymerizing monomers, whether of the same or different types. Accordingly, “polymers” as used herein include homopolymers (used to refer to polymers prepared from only one type of monomer, with the understanding that trace impurities may be incorporated into the polymer structure), and interpolymers, as hereinafter defined. Includes all.

Also, as used herein, the term "PHR" (upper or lower case) refers to the weight of constituents per 100 parts of one or more ethylene-propylene-diene interpolymers (copolymers). The term “parts” with respect to the amount of an ingredient refers to parts by weight of the ingredient in the composition.

In addition, throughout the specification, when a part is said to "include" a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary. In addition, throughout the specification, “above” or “on” means not only the case where it is located above or below the object part, but also the case where there is another part in the middle, and it must be in the direction of gravity. It does not mean that it is located above the standard. In addition, in the present specification, terms such as “first” and “second” do not indicate any order or importance, but are used to distinguish components from each other.

Additionally, as used herein, “preferred” and “preferably” refer to embodiments of the invention that may provide certain advantages under certain circumstances. However, under the same or different circumstances, other embodiments may also be preferred. Additionally, mention of one or more preferred embodiments does not mean that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

<Rubber composition for gasket>

The rubber composition for a gasket according to an embodiment of the present invention is a composition for forming a flame-retardant rubber gasket.

Here, a gasket is a general term for a thin plate-shaped piping material inserted into the joint surface of an object to maintain airtightness. For example, between the entrance door (fire door) of a building and the door frame, sash and window, window and glass, and sash. It is used as a sealing material to airtight the chassis, glass gaps, etc.

For example, the rubber composition for gaskets includes ethylene-propylene-diene (EPDM)-based rubber; Neoprene-based rubber; Chlorinated polyolefin resin; inorganic filler; flame retardants; Process oil is included, and expanded graphite, which significantly expands and foams in volume above a predetermined temperature, is included within a predetermined content range. If necessary, typical additives required for the gasket composition may be further included.

Hereinafter, the composition of the rubber composition for a gasket according to one embodiment will be examined in detail as follows.

Ethylene-propylene-diene (EPDM)-based rubber

In the rubber composition for gaskets of the present invention, ethylene-propylene-diene (EPDM)-based rubber is a base resin that forms a flame-retardant rubber gasket, and plays a role in controlling the density of the entire polymer to express the main physical properties of the base resin.

Ethylene-propylene-diene (EPDM)-based rubber is a terpolymer in which a diene monomer with a carbon-carbon double bond (C=C) is introduced into ethylene and propylene, and diene, the third component, is used to cross-link the rubber. Provides a crosslinking point using sulfur, which is the most common method. The properties of this EPDM-based rubber depend not only on the content ratio of ethylene and propylene, but also on the type and content of diene. Here, dienes include 5-ethylidene-2-norbornene (ENB), dicyclopentadiene (DCPD), and 1,4-hexadiene (HD), of which ENB is widely applied. This EPDM-based rubber has a low degree of unsaturation, so it is very resistant to oxidation and ozone, and has stable insulating properties even at high temperatures. Since it has excellent injection properties by allowing sufficient fillers and plasticizers to be added, weather resistance, insulation resistance, and heat resistance are required. It is applied to various fields. In addition, since the elastomer rubber composed of ethylene-propylene-diene monomer has high flame retardancy, it does not burn because no residual flame is generated in the event of a fire, and thus flame retardancy can be significantly increased.

Conventional gasket compositions mainly use one type of EPDM rubber alone. As more flame retardants are added to one type of EPDM rubber, flame retardancy and foamability improve, but bonding strength decreases, causing problems such as breakage of extrusion. do.

In contrast, in the present invention, by mixing three types of EPDM-based rubbers with different physical properties by adjusting them to a predetermined content ratio, bonding strength can be increased and workability can be improved without deteriorating flame retardancy and foamability. Specifically, in the present invention, the ethylene-propylene-diene (EPDM)-based rubber includes: an oil-free first ethylene-propylene-diene-based rubber; Non-oil-containing second ethylene-propylene-diene rubber; and an oil-containing third ethylene-propylene-diene rubber are mixed together, and their mixing ratio is adjusted to a predetermined range. Here, the first EPDM-based rubber and the second EPDM-based rubber are high diene-based rubber, and the third EPDM-based rubber serves to increase the bonding force between rubber molecules, increase elongation, and demonstrate excellent workability. .

The first to third ethylene-propylene-diene-based rubbers according to the present invention each contain at least two types of monoolefin monomers (carbon atoms 2 to 10, preferably 2 to 4), and at least one type of poly-unsaturated olefin ( It may be a terpolymer derived from 5 to 20 carbon atoms. Here, the monoolefin monomers may each be CH ₂ =CH-R (R is H or an alkyl group of C ₁ to C 1 ₂ ), and may preferably be ethylene and propylene. In addition, the poly-unsaturated olefin may be straight chained, branched, cyclic, bicyclic, bridged ring, etc., and is preferably nonconjugated diene. ) can be. Preferred examples of the first to third ethylene-propylene-diene rubbers are terpolymers containing ethylene/propylene/diene, where the diene is ENB (ethylidene norbornene).

For example, the first ethylene-propylene-diene rubber has an ENB (ethylidene norbornene) content of 4.5 to 12% by weight, an ethylene content of 50 to 80% by weight, and a Mooney viscosity ( Mooney viscosity, ML1+4, 125℃) may be 15 to 35. Preferably, the content of ENB (ethylidene norbornene) is 5 to 10% by weight, the content of ethylene is 50 to 70% by weight, and the Mooney viscosity (ML1+4, 125°C) is 20 to 35. It can be. Additionally, the weight average molecular weight (Mw) of the first EPDM-based rubber may be 10,000 to 100,000 g/mol, specifically 30,000 to 80,000 g/mol, and more specifically 40,000 to 60,000 g/mol. If the physical properties of the first EPDM-based rubber are lower than the above-mentioned range, shape recovery is disadvantageous, and if it exceeds the above-mentioned range, it may cause work defects due to poor flow during extrusion molding or may require a long processing time. It may take some time. An example of the first commercialized EPDM-based rubber product that satisfies the above-mentioned physical properties is KEP-330 from Kumho Polychem.

For another specific example, the second ethylene-propylene-diene rubber has an ENB (ethylidene norbornene) content of 4.5 to 12% by weight, an ethylene content of 50 to 80% by weight, and a Mooney viscosity of (Mooney viscosity, ML1+4, 125℃) may be 45 to 65. Preferably, the content of ENB (ethylidene norbornene) is 5 to 10% by weight, the content of ethylene is 50 to 70% by weight, and the Mooney viscosity (ML1+4, 125°C) is 50 to 65. It can be. Additionally, the weight average molecular weight (Mw) of the second EPDM-based rubber may be 10,000 to 100,000 g/mol, specifically 30,000 to 80,000 g/mol, and more specifically 40,000 to 60,000 g/mol. The Mooney viscosity of the second EPDM-based rubber is higher than that of the above-mentioned first EPDM-based rubber, making it relatively hard and easy to blend with diene-based rubber, thus providing excellent workability. An example of a commercialized second EPDM-based rubber product that satisfies the above-mentioned physical properties is KEP-350 from Kumho Polychem.

For another specific example, the third ethylene-propylene-diene rubber has an ENB (ethylidene norbornene) content of 3.0 to 10% by weight, an ethylene content of 60 to 90% by weight, and a Mooney viscosity of (Mooney viscosity, ML1+4, 125℃) may be 40 to 70. Preferably, the content of ENB (ethylidene norbornene) is 4 to 8% by weight, the content of ethylene is 65 to 80% by weight, and the Mooney viscosity (ML1+4, 125°C) is 40 to 65. It can be.

The third EPDM-based rubber is an oil extended rubber, which is a mixture of synthetic rubber and a predetermined petroleum emulsion and is added to increase the elongation rate. The oil contained in this third EPDM-based rubber refers to extender oil, which is distinguished from process oil (process oil), which will be described later. Extender oil is an oil added for volume increase and plasticization in the rubber manufacturing process, and may be one or more of common aromatic, paraffinic, and naphthenic oils known in the art, and specifically, paraffinic white oil. , it may be paraffin-based process oil, naphthenic-based process oil, aromatic-based process oil, etc. The content of oil contained in the third EPDM-based rubber may be 30 to 70 parts by weight (per hundred rubber, phr) based on the total weight of the rubber, but is not particularly limited thereto. If the physical properties of the third EPDM-based rubber according to the present invention are lower than the above-mentioned range, the vulcanization time during extrusion may be delayed, which may cause problems such as non-vulcanization and shape defects, and if it exceeds the above-mentioned range, the vulcanization time may be delayed. If it is too fast, scorch may occur in the product due to over-vulcanization. In fact, high molecular weight EPDM rubber has poor mixing workability, but the third EPDM-based rubber can ensure good mixing workability by containing oil in the above-mentioned range. An example of a second commercialized EPDM-based rubber product that satisfies the above-mentioned physical properties is KEP-960 from Kumho Polychem.

For example, the mixing ratio of the first EPDM-based rubber, the second EPDM-based rubber, and the third EPDM-based rubber may be 4 to 6: 0.3 to 2.5: 3 to 5 by weight. Preferably, the weight ratio is 4.5 to 5.5:0.5 to 1.5:3.5 to 4.5, and more preferably, the weight ratio is 5:1:4. When the above-mentioned mixing ratio is satisfied, not only is foamability excellent, but the bonding force is weak and extrusion may be difficult. If the above-mentioned mixing ratio is exceeded, the bonding force is excellent and extrusion processability is excellent, but foaming may be difficult.

In the present invention, at least three types of ethylene-propylene-diene (EPDM)-based rubber mixtures including the above-described first to third ethylene-propylene-diene-based rubbers are prepared according to KS M 6518: 2016. The tensile strength measured according to the standard may be 5.5 to 7.0 MPa, and the elongation may be 4.8×10 ² to 6.0×10 ² . Preferably, the tensile strength is 5.7 to 6.5 MPa and the elongation is 4.8×10 ² to 5.5×10 ² .

In the present invention, the content of at least three types of ethylene-propylene-diene (EPDM)-based rubber is not particularly limited, and for example, is 20 to 50 parts by weight based on the total weight (e.g., 100 parts by weight) of the rubber composition. may be, preferably 30 to 45 parts by weight. When the content of the ethylene-propylene-diene-based rubber falls within the above-mentioned range, it exhibits excellent durability, resilience, and heat resistance, and at the same time increases the bonding force between rubber molecules, enabling high flame retardancy and expression of various colors. For example, in the present invention, the content of the first ethylene-propylene-diene-based rubber may be 10 to 30 parts by weight based on the total weight (e.g., 100 parts by weight) of the rubber composition, and the second ethylene-propylene- The content of the diene-based rubber may be 1 to 15 parts by weight, and the content of the third ethylene-propylene-diene-based rubber may be 5 to 25 parts by weight.

Neoprene-based rubber

The rubber composition for gaskets of the present invention includes neoprene-based rubber.

Neoprene-based rubber is a polymer of chloroprene, and has weather resistance, chemical resistance, and flame retardancy that ordinary rubber does not have. It has strong adhesion and is mainly used in areas containing chlorine, such as rubber adhesives, ships, construction, and electric wires.

The neoprene-based rubber may be a typical neoprene rubber known in the art, and may be polymerized using, for example, acetylene or butadiene as a starting material.

For example, the neoprene-based rubber may have a Mooney Viscosity (ML1+4) of 35 to 60, specifically 40 to 55. If the pattern viscosity of neoprene-based rubber is less than 35, it is not advantageous for mixing with raw rubber, and if it exceeds 60, processability is reduced, so it is preferable to have a pattern viscosity in the above-mentioned range.

In addition, the neoprene-based rubber may be a highly crystalline resin, and the solid content (solid content excluding moisture) may be 1% to 10% based on the total weight of the neoprene-based rubber resin. If the solid content is outside the above-mentioned range, it is difficult to smoothly carry out a polymerization reaction with a polymer emulsion, etc., and the intended effect of the present invention due to the addition of neoprene-based rubber cannot be achieved, which is not desirable.

In the present invention, the content of neoprene-based rubber is not particularly limited, and may be, for example, 1 to 15 parts by weight, preferably 2 to 10 parts by weight, based on the total weight (e.g., 100 parts by weight) of the rubber composition. am. When neoprene-based rubber falls within the above-mentioned content range, extrudability and bonding properties can be improved without deteriorating flame retardancy.

Chlorinated polyolefin resin

The rubber composition for a gasket of the present invention contains a chlorinated polyolefin-based resin for the purpose of reinforcing adhesion and impact properties.

The chlorinated polyolefin-based resin may be any conventional resin known in the art without limitation, and for example, chlorinated polyethylene resin, chlorinated polypropylene resin, or all of these may be used.

For example, the chlorinated polyolefin-based resin may include at least one type of chlorinated polyethylene resin in which some of the hydrogen in the resin is replaced with chlorine and the chlorination degree is 5 to 40% by weight.

Here, the degree of chlorination refers to the weight occupied by chlorine relative to the total weight of the chlorinated polyolefin resin as part of the hydrogen in the molecule of the resin is replaced with chlorine. Specifically, it is more preferable to use a chlorination degree of 5 to 40% by weight, more specifically, a chlorination degree of 20 to 30% by weight because it can exhibit better adhesive strength.

In the present invention, by mixing at least two types of chlorinated polyolefin-based resins with different physical properties by adjusting them to a predetermined content ratio, bonding strength can be increased and workability can be improved without deteriorating flame retardancy and foamability. Specifically, in the present invention, CPE135 and C6235 can be used together as examples of commercialized chlorinated polyolefin resins, and in this case, their mixing ratio may be 1:0 to 1.5 weight ratio.

In the present invention, the content of the chlorinated polyolefin-based resin is not particularly limited, and may be, for example, 1 to 15 parts by weight, preferably 3 to 10 parts by weight, based on the total weight (e.g., 100 parts by weight) of the rubber composition. It is wealth. When the chlorinated polyolefin-based rubber falls within the above-mentioned content range, it can exhibit excellent bonding properties without deteriorating flame retardancy.

inorganic filler

In the rubber composition for a gasket of the present invention, an inorganic filler is used to improve the physical bonding force of the rubber composition and to increase processability and reinforcement properties. In addition, it can perform the function of controlling the content of EPDM-based rubber by adjusting the content of the inorganic filler.

The inorganic filler may be any ingredient known in the art without limitation, and examples include calcium carbonate (CaCO ₃ ), talc, magnesium carbonate, clay, talc, barium sulfate, silica, mica, titanium oxide, carbon black, Examples include graphite, metal oxide, carbon nanotubes, graphite, wollastonite, or nanosilver. The above-mentioned ingredients can be used alone or in combination of two or more. Preferably, calcium carbonate or talc may be used, and more preferably, calcium carbonate may be used. Calcium carbonate (CaCO ₃ ) can serve as a flame retardant auxiliary function.

The form of the inorganic filler is not particularly limited, and for example, either particle or fiber form can be used. When using particulate inorganic fillers, the average particle diameter (d50) of these inorganic fillers may be 0.1 to 20 ㎛, specifically 0.01 to 5 ㎛. Additionally, the inorganic filler may be coated or uncoated with a surface treatment agent such as a coupling agent.

In the present invention, the content of the inorganic filler is not particularly limited, and for example, may be 3 to 30 parts by weight, preferably 5 to 15 parts by weight, based on the total weight (e.g., 100 parts by weight) of the rubber composition. there is. When the content of the inorganic filler falls within the above-mentioned range, mechanical properties such as heat resistance and chemical resistance and processability are excellent.

flame retardant

In the rubber composition for gaskets of the present invention, the flame retardant improves the flame retardancy of the gasket and prevents the gasket from burning easily or generating toxic gas in the event of a fire.

The flame retardant may be any flame retardant component known in the art, that is, inorganic or organic, without limitation. For example, organic systems such as phosphorus-based, nitrogen-based, and halogen-based; Inorganic types such as metal hydroxide type, antimony type, molybdenum type, and zinc borate type; Or a combination thereof can be used.

According to one embodiment of the present invention, the flame retardant is a metal hydroxide-based first flame retardant; Antimony-based secondary flame retardant; and at least one of a halogen-based third flame retardant. Preferably, a metal hydroxide-based first flame retardant, an antimony-based second flame retardant, and a halogen-based third flame retardant are used together, more preferably at least two types of first flame retardants, antimony-based second flame retardants, and at least two types of flame retardants. A third flame retardant is used in combination.

The metal hydroxide-based first flame retardant is not particularly limited, and may be, for example, one or more selected from the group consisting of aluminum hydroxide, magnesium hydroxide, and potassium hydroxide. Preferably, aluminum hydroxide and magnesium hydroxide are used together.

Aluminum hydroxide [Al(OH) ₃ ] is a representative inorganic flame retardant. It is non-toxic (halogen-free) and has low smoke properties. As the temperature of the polymer decreases, it plays a role in suppressing combustion. In particular, aluminum hydroxide causes an endothermic reaction when a fire occurs, so it reduces the temperature rise and suppresses the movement of combustion. It can also improve the heat resistance of the gasket by assisting the function of a flame retardant. This aluminum hydroxide is a product of a combustion reaction and generates moisture and metal oxides, which are incombustibles, thereby blocking contact with oxygen, which is the cause of combustion, and can further improve the fire resistance of the gasket. In addition, magnesium hydroxide [Mg(OH) ₂ ] can improve the scratch resistance of products and suppress the generation of toxic gases and smoke.

The antimony-based second flame retardant is not particularly limited, and conventional antimony-containing flame retardants known in the art can be used. Preferably, antimony trioxide is used. Antimony trioxide is a white crystalline powder of sheep oxide that turns yellow when heated and becomes metallic antimony when reduced with hydrogen gas or charcoal. It is used as a flame retardant adjuvant, improves flame retardancy when used in polymer resin products, and is a halogen flame retardant. When mixed with , flame retardancy increases.

Additionally, the halogen-based third flame retardant is not particularly limited, and conventional antimony-containing flame retardants known in the art can be used. For example, one or more types selected from the group consisting of decabromine and chlorinated paraffin can be used, and decabromine and chlorinated paraffin are preferably used together.

In the present invention, the usage ratio of the first metal hydroxide-based flame retardant, the second antimony-based flame retardant, and the third halogen-based flame retardant is not particularly limited, and may be, for example, a weight ratio of 50-90:3-20:7-30. When the first to third flame retardants are mixed at a predetermined content ratio, the six major heavy metals that are standard for domestic and overseas environmental regulations [e.g., cadmium (Cd), lead (Pb), mercury (Hg), hexavalent chromium (Cr), It is possible to provide a gasket material with excellent flame retardancy without being subject to environmental regulations for [two types of brominated flame retardants (PBBs, PBDEs)].

In addition to the first to third flame retardants described above, common nitrogen-based flame retardants or phosphorus-based flame retardants known in the art may be additionally mixed. Examples of such nitrogen-based flame retardants include at least one of ammonium phosphate, ammonium carbonate, triadine compound, melamine cyanurate, or guanidine compound, and examples of the phosphorus-based flame retardant include melamine polyphosphate, ammonium polyphosphate, and diammonium. It may be at least one of phosphate, monoammonium phosphate, polyphosphate amide, phosphate amide, melamine phosphate, or red phosphate.

In the present invention, the content of the flame retardant is not particularly limited and may be, for example, 20 to 60 parts by weight, preferably 30 to 50 parts by weight, based on the total weight (e.g., 100 parts by weight) of the rubber composition. When the content of the flame retardant falls within the above-mentioned range, the flame retardancy and mechanical properties of the composition can be developed simultaneously.

expanded graphite

The rubber composition for a gasket of the present invention includes expandable graphite for the purpose of maintaining tighter airtightness by thermally expanding above a predetermined temperature.

The expanded graphite can be used as conventional thermally expanded graphite known in the art. For example, natural flaky graphite can be used by chemically treating it with an acidic material and drying it by infiltrating an acidic compound between the layers of the graphite.

Expanded graphite is a halogen-free flame retardant that exfoliates faster than its initial volume when exposed to high temperatures and forms a low-density thermal insulation layer on the heated surface to prevent the polymer from burning further. Additionally, since expanded graphite itself is non-combustible, it is applied to a variety of non-combustible or flame-retardant products. In particular, in the case of the gasket of the present invention equipped with thermally expanded foamed graphite, the space between the door frame and fire door (entrance door) of the building in which the gasket is installed, the space between the sash and the window, the window and the glass, the sash and the sash, and the glass gap are airtight, They can be firmly supported and in surface contact. Accordingly, in the event of a fire, loss of life and property damage can be minimized by blocking the loss and spread of flames and harmful gases.

For example, the expanded graphite expands 100 to 300 times when heated to 150°C or higher, and may have a particle size of 60 to 300 mesh and a carbon component of 95% by weight or more. More specifically, it can expand 200 to 300 times when heated to 150°C or higher, and can have a particle size of 100 to 300 mesh and a carbon content of 97% by weight or more.

In the present invention, the content of expanded graphite is not particularly limited and may be, for example, 5 to 15 parts by weight, preferably 7 to 15 parts by weight, based on the total weight (e.g., 100 parts by weight) of the rubber composition. . When the content of expanded graphite falls within the above-mentioned range, in addition to excellent flame retardant effect, a tight airtight effect can be continuously maintained through significant thermal expansion when the temperature rises above a predetermined temperature.

process oil

In the rubber composition for a gasket of the present invention, the process oil serves to provide fluidity to the rubber composition and is used as a softener to reduce the hardness of the thermoplastic elastomer.

Specifically, process oil refers to oil (process oil, processing oil) added in the process of kneading the composition using a roller or Banbury mixer. These process oils are added during the processing of rubber products to improve elasticity and plasticity, thereby improving the dispersion of fillers, and are also used to save heat and time by facilitating overall workability such as mixing molding.

As the process oil, oils commonly used in combination with the specific rubber of the composition according to the present invention can be used without limitation. For example, naphthenic oil, paraffinic oil, olefinic oil, aromatic oil, mineral oil, vegetable oil, or synthetic oil derived from petroleum fractions in the art may be used. The above-mentioned ingredients may be used alone or at least two or more oils may be used in combination.

For one embodiment of the present invention, the process oil may be at least one of paraffinic oil or naphthenic oil, and preferably may be paraffinic oil. These paraffinic oils are most effective in improving fluidity and preventing deterioration of flame retardancy.

In addition, the process oil has a kinematic viscosity at 40°C of 95 cSt to 150 cSt, a flash point may be 220°C to 300°C, and preferably, a kinematic viscosity at 40°C of 110 cSt to 120 cSt, The flash point may be 250°C to 270°C. If it has the above-mentioned physical properties, mixing during extrusion is advantageous and sufficient fluidity can be provided.

For example, the paraffinic oil may have a weight average molecular weight (Mw) of 400 to 1,200 g/mol, specifically 600 to 900 g/mol. Additionally, the specific gravity (15/4°C) may be 0.75 to 0.95, specifically 0.85 to 0.9.

In the present invention, the content of the process oil is not particularly limited and, for example, may be 1 to 20 parts by weight, preferably 2 to 10 parts by weight, based on the total weight (e.g., 100 parts by weight) of the rubber composition. . If the content of process oil is less than the above-mentioned range, the hardness of the composition increases and fluidity decreases, causing processing problems, and if it exceeds the above-mentioned range, the hardness is excessively lowered and mechanical properties such as heat resistance and chemical resistance are significantly reduced. It may deteriorate, and it is difficult to provide flame retardancy.

additive

In addition to the above-mentioned components, the rubber composition for a gasket of the present invention can use additives known in the art without limitation as long as they do not impair the effect of the invention.

Non-limiting examples of additives that can be used include pigments, colorants, moisture absorbents, slip agents, antioxidants, lubricants, anti-aging agents, foaming agents, cross-linking agents, cross-linking aids, processing aids, vulcanizing agents, binders, coupling agents, heat stabilizers, or There are UV stabilizers, etc. These can be used alone or two or more types can be used together.

These additives may be appropriately included within a range that does not impair the physical properties of the rubber composition, and for example, may be 0.001 to 20 parts by weight, preferably 0.1 to 15 parts by weight, based on the total weight of the gasket rubber composition. It could be wealth.

Looking at the composition of usable additives in detail, they are as follows.

Pigment is included for the purpose of developing a desired color in the gasket. In particular, conventional gaskets using EPDM-based rubber were mainly produced using black carbon. In contrast, in the present invention, at least three types of EPDM-based rubber, neoprene-based rubber, and chlorinated polyolefin-based resin that increase the bonding force between rubber molecules are mixed in a predetermined range, and ordinary pigments are added to provide various colors including black as well as gray. Colored gasket products can be provided. These pigments are divided into organic pigments and inorganic pigments. The content and physical properties of the pigments included in the composition vary depending on the color of the pigment, and the light inflow and outflow blocking properties of the final gasket vary accordingly. Taking this into consideration, it is appropriate to use a pigment of an appropriate color.

The pigment may be any of organic pigments, inorganic pigments, metallic pigments, pearls, etc. commonly used in gasket compositions without limitation, and may be used alone or in combination of two or more. More specifically, one type or a mixture of two or more types selected from the group consisting of black titanium dioxide, bismuth vanadate, cyanine green, carbon black, white carbon, iron oxide, iron sulfur oxide, navy blue, and cyanine blue can be used. The average particle size (particle diameter) of the pigment is not particularly limited, but is preferably approximately 10 ㎛ or less. The content of the pigment is not particularly limited, but may be about 0.1 to 5 parts by weight based on the total weight of the gasket rubber composition. Additionally, various dyes known in the art can be used as colorants without limitation.

Antioxidants (antioxidants) are also called antioxidants because they prevent aging of organic polymer materials and play the same role as antioxidants in preventing oxidation. These anti-aging agents act to stop the chain reaction of auto-oxidation caused by oxygen, which is a major factor in the aging phenomenon. Such anti-aging agent may be at least one of phenol-type, phosphite-type, thioether-type, and amine-type antioxidants. Non-limiting examples of anti-aging agents that can be used include hindered phenols, bisphenols, and thiobisphenols; substituted hydroquinone; tris(alkylphenyl)phosphite; dialkylthiodipropionate; phenylnaphthylamine; substituted diphenylamine; 4,4'-bis(a,a-dimethylbenzyl) diphenylamine, octylated diphenylamines, dialkyl, alkylaryl , and diaryl substituted p-phenylene diamine; monomeric and polymeric dihydroquinolines; 2-(4-hydroxy-3,5-t-butylaniline)-4,6-bis(octylthio)1,3,5-triazine, hexahydro-1,3,5-tris-β-( 3,5-di-t-butyl-4-hydroxyphenyl)propionyl-s-triazine, 2,4,6-tris(n-1,4-dimethylpentylphenylene-diamino)-1,3 ,5-triazine, tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, nickel dibutyldithiocarbamate, 2-mercaptolylimidazole and zinc thereof. It may be salt, petroleum wax, etc.

Blowing agents are useful in producing foam structures. As such a blowing agent, decomposable chemical blowing agents, inorganic blowing agents, or all of them known in the art can be used in combination. The inorganic foaming agent includes ammonium carbonate, sodium bicarbonate, anhydrous sodium nitrate, etc. In addition, a chemical foaming agent is a substance that decomposes at elevated temperatures to form gas or vapor and foams the polymer into a foam. Non-limiting examples include azodicarbonamide, azodiisobutyro-nitrile, barium azodicarboxylate, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, N,N'-dinitrosopentamethylenetetramine, benzenesulfonehydrazide, 4,4-oxybenzene sulfonyl semicarbazide, p -Toluene sulfonyl semicarbazide, p,p'-oxybis-(benzenesulfonyl hydrazide), 3,3'-disulfone hydrazide-diphenyl sulfone, azobisisobutyronitrile, azobisformamide etc. The above-described foaming agents may be used alone or in a mixture of two or more.

As a mold release agent, a fluorine-containing polymer, silicone oil, metal salt of stearic acid, metal salt of montanic acid, montanic acid ester wax, or polyethylene wax can be used. Additionally, a benzophenone type or amine type weatherproofing agent can be used as a weathering agent. Titanium dioxide (TiO ₂ ) or carbon black can be used as a sunscreen, and talc or clay can be used as a nucleating agent. In addition, as a moisture absorbent, one or more selected from the group consisting of silica types such as sillitin and calcium oxide (CaO) may be used in consideration of preventing the generation of bubbles on the surface of the foam.

Processing aids help the mixing agents to be uniformly dispersed during the process of mixing the rubber composition and play a role in controlling the adhesion of the rubber composition. In addition, it lowers the pattern viscosity, improving mill release properties and mold release properties. Examples of processing aids that can be used may be fatty acids or waxes.

Crosslinking aids are used to increase crosslinking speed and increase crosslinking density by preventing side chain reactions. As an example of a crosslinking aid, compounds such as metal oxide, metal halide, or stearic acid can be used. Specific examples include ZnO, SnCl ₂ , steric acid, zinc stearate, etc. there is.

The vulcanizing agent may be any crosslinking agent capable of curing the elastomer without substantially decomposing and/or hardening the thermoplastic polymer, and may be used in embodiments of the present invention. Preferred crosslinking agents are phenolic resins because phenolic resin curing systems provide a better balance of properties than other curing systems. Other curing agents that can be used include, but are not limited to, peroxides, azides, poly(sulfonyl azides), aldehyde-amine reaction products, vinyl silane graft moieties, hydrosilylation, substituted ureas, substituted guanidines; substituted xanthate; substituted dithiocarbamate; Sulfur-containing compounds such as thiazole, imidazole, sulfenamide, thiuramidisulfide, paraquinonedioxime, dibenzoparaquinonedioxime, sulfur; and combinations thereof.

Slip agents are used to improve productivity by improving release properties from molds during gasket injection, and to improve part performance by improving wear resistance. These slip agents may be long-acting slip agents, fast-acting slip agents, or combinations thereof known in the art, and specific examples include polydimethyl siloxane (PDMS), oleamide, and erucamide. ), oleyl palmitamide, stearly erucamide, ethylene bis oleamide, etc.

In addition, it may further include an ultraviolet absorber (e.g., triazine-based), a light stabilizer (e.g., HALS), a surfactant, an antifoaming agent (e.g., dimethylpolysiloxane), a neutralizer, a stabilizer, an antistatic agent, an antibacterial agent, etc.

The method for producing the rubber composition for gaskets according to the present invention is not particularly limited, and methods known in the art can be applied without limitation. As an example of this manufacturing method, EPDM-based rubber, neoprene-based rubber, chlorinated polyolefin-based resin, inorganic filler, flame retardant, expanded graphite, process oil, and other additives mixed as necessary are prepared by conventional methods known in the art. After configuring them accordingly, they can be prepared by mixing and stirring them at a specific ratio.

More specifically, the rubber composition for a gasket is prepared by mixing at least one type of chlorinated polyolefin-based resin, weighing and mixing at least three types of EPDM-based rubber and neoprene-based rubber, and adding inorganic substances, flame retardants, expanded graphite, and It can be manufactured by adding process oil and other additives and mixing them in a rubber mixer, then extruding the rubber and vulcanizing it.

At this time, conventional methods can be used to mix the composition, for example, single-screw and twin-screw extruders, super-mixers, banbury-mixers, various kneaders, and rolls. A kneading device such as this may be used.

For a specific example, the rubber composition for a gasket may include 20 to 50 parts by weight of ethylene-propylene-diene (EPDM)-based rubber, based on 100 parts by weight of the composition; 1 to 15 parts by weight of neoprene-based rubber; 1 to 15 parts by weight of olefin chloride resin; 3 to 30 parts by weight of inorganic filler; 20 to 60 parts by weight of flame retardant; 5 to 15 parts by weight of expanded graphite; and 1 to 20 parts by weight of process oil, and, if necessary, may further include other additives satisfying a total of 100 parts by weight.

The rubber composition for a gasket of the present invention configured as described above may have a viscosity of 30 to 50 cps at 25°C, specifically 35 to 45 cps. By adjusting the viscosity to an appropriate range, excellent workability and fairness can be achieved.

The rubber composition for gaskets of the present invention, composed as described above, has physical properties such as flame retardancy, heat resistance, durability, recovery (elasticity), chemical resistance, and processability, and can be easily molded by injection molding, extrusion molding, etc., which are characteristics of general thermoplastic resins. It can be molded. Accordingly, gaskets and molded products made from the rubber composition for gaskets of the present invention can be usefully applied to various fields. For example, it can be applied to molded products provided in interior and exterior building parts, for example, sealing parts of fire doors (entrance doors), and more specifically, between the door frame and fire doors (entrance doors) of buildings where gaskets can be installed, sashes and windows, It can be applied to separated spaces such as windows and glass, sash to sash, and glass gaps. In addition, it can be applied as a gasket for electronic parts, automobile parts, medical supplies, household goods, office supplies, leisure goods, and household goods.

<Flame retardant expansion gasket>

In addition, the present invention provides a molded product using the above-described gasket rubber composition, preferably a flame retardant expansion gasket.

Here, the molded product refers to all molded products manufactured through various molding processes such as injection molding, blow molding, extrusion molding, and thermoforming using the above-described rubber composition. Specifically, it may be a molded product provided for building interior and exterior materials, various electrical and electronic components, or automobile parts. In particular, it may be a molded product used in building interior and exterior materials, such as between the door (fire door) and the door frame, sash and window, window and glass, sash and sash, glass gap, etc. A fire door flame retardant gasket that is disposed in the separation space and functions as a sealing member is preferable.

The flame retardant expansion gasket according to the present invention may be manufactured according to a conventional method known in the art, and may be carried out as in the following example. This manufacturing method is not limited to the following method or sequence, and the steps of each process may be modified or selectively mixed as needed.

An example of the method for manufacturing the flame retardant expansion gasket includes (i) a first mixture manufacturing step ('S10 step') of mixing the above-described gasket rubber composition and then aging it; (ii) a secondary mixture manufacturing step ('S20 step') of mixing the primary mixture and then maturing it; (iii) extrusion molding the secondary mixture ('S30 step'); and (iv) vulcanizing the result obtained in step (iii) while passing it through a vulcanization equipment ('S40 step'); and a foaming step ('S50 step') of crosslinking and foaming the result of step (iv).

The first mixture preparation step ('S10 step') is mixing the rubber composition of the present invention including EPDM-based rubber, neoprene-based rubber, chlorinated polyolefin-based resin, inorganic filler, flame retardant, expanded graphite, process oil, and other additives. This is the stage of maturing. For example, after mixing at least one type of chlorinated polyolefin-based resin, at least three types of EPDM-based rubber and neoprene-based rubber are weighed and mixed, and inorganic substances, flame retardants, expanded graphite, process oil, and other additives are added to the prepared mixture. Add and mix.

For a specific example of this S10 step, the above-described rubber composition is put into a Banbury-mixer (e.g., 22-inch roll) and then uniformly mixed while applying a temperature of 150 to 200 ° C., specifically 170 to 185 ° C. Disperse and cool. To stabilize the thermal history of the raw materials, it is preferable to ripen and dry at a temperature within 20°C for 12 to 36 hours, specifically 20 to 26 hours.

Next, in the secondary mixture manufacturing step ('S20 step'), the primary mixture is put into a kneader (e.g., 18 inch row), and then secondary dispersion and Mix and ribbon work. After cutting it to a certain size in a two-roll mill within 80℃ and within 5 minutes considering the input of the sheet and extruder, it is aged for more than 12 hours, specifically about 20 to 26 hours, at a temperature within 20℃ to stabilize the secondary mixture. Drying is preferred.

In step S20, a crosslinking agent and a crosslinking accelerator known in the art may be added to the above-mentioned primary mixture. For example, considering the crosslinking reaction temperature in a kneader, it is preferable to mix within 80°C and within 10 minutes.

Thereafter, the mixture prepared in step S20 is extruded using an extruder ('step S30').

For example, in step S30, extrusion molding is performed after attaching a mold to a ㆈ90 extruder. This extrusion molding is carried out in various forms (tube-inner diameter × outer diameter, sheet-width × thickness) in consideration of KS standards. It is desirable to maintain the extrusion temperature within 80°C considering the crosslinking temperature.

Next, it is vulcanized while passing through an extruder and a vulcanization facility (vulcanization tank) to obtain the physical properties of rubber ('S40 step').

To give a specific example of step S40, a glass bead heated to 200 to 250°C, specifically 220 to 240°C, provided inside a vulcanization facility (vulcanization tank) of approximately 35 m, is allowed to pass for approximately 100 m.

Afterwards, the extruded molded product is crosslinked and foamed.

This foaming step ('S50 step') may be accomplished by crosslinking and foaming the mixture prepared through the secondary mixture preparation step ('S20 step'), cooling, pulling, and winding. The molding temperature in the foaming step ('S50 step') can be within a temperature of 110 to 180°C, taking into account the decomposition temperature of the crosslinking agent and foaming agent. In this process, control of the crosslinking-foaming speed has a significant impact on the cell structure. do.

In step S50, the pulling process and winding process may use a conventional take-up machine and a winding machine known in the art, respectively. Here, the take-up machine pulls the vulcanized molded product at a constant speed, and the winder is a process of wrapping the take-up product to an appropriate length and packaging it.

The flame retardant expansion gasket of the present invention manufactured through the above-described process is installed on the interior and exterior materials of a building, etc. to seal the space between the door (fire door) and the door frame, between the sash and the window, between the window and the glass, between the sash and the sash, and between the glass gaps. It exhibits secondary airtightness, and by containing expanded graphite, which significantly expands in volume, it can continuously exhibit secondary airtightness that prevents the spread of flames and harmful gases in the event of a fire. Accordingly, excellent flame retardancy, extrusion processability, graphite expandability, and eco-friendliness can be secured at the same time. Specifically, the flame retardant expansion gasket according to an embodiment of the present invention can satisfy the physical property conditions (i) and (ii) below. (i) The flame resistance of the specimen measured according to the UL-94 standard is V-0 or higher, and (ii) the hazardous substances (Hg, Pb, Cd) according to the IEC 62321-4, IEC 62321-5, and IEC 62321-6 standards. , Cr, PBBs/PBDEs) (see Table 5 below).

The flame retardant expansion gasket according to the present invention includes interior and/or exterior material components for buildings that require excellent flame retardancy, durability, heat resistance, processability, wear resistance, and restoration, electronic components, automobile parts, medical supplies, household goods, office supplies, and leisure goods. and household goods, etc. For a specific example, the space between the door (fire door) and the door frame of the building's interior and exterior materials, between the sash and the window, between the window and the glass, between the sash and the sash, and between the glass gaps is first sealed, and in the event of a fire, the space is thermally expanded to prevent flames and harmful gases by 2. It can be used as a flame retardant thermally expandable gasket for airtight sealing and blocking. However, it is not particularly limited to this.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are only intended to aid understanding of the present invention and do not limit the scope of the present invention to the examples in any way.

[Example 1]

The physical properties of each component used in the examples and comparative examples herein are shown in Table 1 below. The rubber composition for the gasket and the gasket of Example 1 were respectively prepared using EPDM-based rubber, neoprene-based rubber, chlorinated polyethylene-based resin, inorganic filler, flame retardant, expanded graphite, process oil, and other additives according to the composition in Table 2 below. did.

Specifically, after mixing two types of chlorinated polyethylene resins, three types of EPDM-based rubber and neoprene-based rubber were added and mixed. Next, the inorganic filler and flame retardant were added and mixed in a rubber mixer, then the rubber was extruded and a vulcanization process was performed.

In the case of the rubber composition for a gasket of Example 1, not only was the shape of the gasket maintained during operation, but workability was good. In addition, the gasket manufactured in Example 1 showed excellent flame retardancy and environmental friendliness in terms of flame retardancy and toxicity.

[Example 2]

The rubber composition for a gasket of Example 2 was prepared in the same manner as Example 1, except that one type of chlorinated polyethylene resin was used instead of two types of chlorinated polyethylene resin, and the content of the composition was changed as shown in Table 1 below. and gaskets were manufactured, respectively.

In the case of the rubber composition for a gasket of Example 2, not only was the shape of the gasket maintained during operation, but workability was good. Additionally, the gasket manufactured in Example 2 showed excellent flame retardancy and environmental friendliness in terms of flame retardancy and toxicity.

composition Detailed specification
EPDM rubber
(A) A-1 1st EPDM
[(ML1+4, 125℃=28, ENB content=7.9 wt%, ethylene content=57 wt%] A-2 2nd EPDM
[(ML1+4, 125℃=56, ENB content=7.9 wt%, ethylene content=57 wt%] A-3 3rd EPDM
[(ML1+4, 125℃=49, ENB content=5.7 wt%, ethylene content=70 wt%] Neoprene type
Rubber (B) B Neoprene rubber (EM40, Mooney viscosity = 48) Chlorinated polyolefin resin (C) C-1 Monochlorinated polyethylene (CPE135) C-2 Polyethylene chloride (C6235) Inorganic filler (D) D calcium carbonate Flame retardant (E) E-1 Al(OH) ₂ E-2 Mg(OH) ₂ E-3 Antimony trioxide E-4 Decabromine E-5 Chlorinated paraffin Expanded Graphite (F) F expanded graphite Process oil (G) G Paraffinic oil Additives (I) I Activated zinc stearic acid

Example Comparative example One 2 One 2 3 4 5 EPDM series
rubber A-1 15 17 21 22 23 23 22 A-2 3 4 - - 5 - - A-3 10 15 16 17 10 11 10 Neoprene type
rubber B 4 5 - - - 5 - Chlorinated polyolefin resin C-1 3 3 - - - - 2 C-2 3 - - - - - 5 inorganic filler D 5 5 5 5 5 5 5 flame retardant E-1 14 13 14 13 13 12 14 E-2 13 12 13 12 12 11 11 E-3 2 One 3 3 4 4 3 E-4 3 2 6 5 6 6 5 E-5 5 3 - - - - - expanded graphite F 10 10 10 10 10 10 10 process oil G 5 5 7 8 7 8 8 additive I 5 5 5 5 5 5 5 Total (parts by weight) 100 100 100 100 100 100 100

[Comparative Example 1]

Except that the composition was changed as shown in Table 1, the rubber composition for the gasket and the gasket of Comparative Example 1 were manufactured in the same manner as in Example 1.

Specifically, in the case of Comparative Example 1, in which two types of EPDM-based rubber were mixed without using chlorinated polyethylene resin and neoprene-based rubber, and then inorganic filler, flame retardant, expanded graphite, process oil, and additives were added, foaming occurred during the rubber mixing operation. The bonding strength of graphite decreased, and due to this bonding problem, it was difficult to maintain the shape of the product extruded with the gasket. However, the flame retardancy was relatively good.

[Comparative Example 2]

Except that the composition was changed as shown in Table 1, the rubber composition for the gasket and the gasket of Comparative Example 2 were manufactured in the same manner as in Example 1.

Specifically, in the case of Comparative Example 2, in which two types of EPDM-based rubber are mixed without using chlorinated polyethylene resin and neoprene-based rubber, and then inorganic filler, flame retardant, expanded graphite, process oil, and additives are added, the rubber mixing operation is It was smooth, and extrusion with the gasket was also good. However, due to bonding problems, it was difficult to maintain the shape of the gasket product, and productivity problems and flame retardancy did not reach the target values.

[Comparative Example 3]

Except that the composition was changed as shown in Table 1, the rubber composition for the gasket and the gasket of Comparative Example 3 were manufactured in the same manner as in Example 1.

Specifically, In Comparative Example 3, in which three types of EPDM-based rubber were mixed without using chlorinated polyethylene resin and neoprene-based rubber, and then inorganic filler, flame retardant, expanded graphite, process oil, and additives were added, the bonding power of the flame retardant during extrusion molding was low. As a result, it was confirmed that the bonding of the molding was significantly reduced and the surface was very rough.

[Comparative Example 4]

Except that the composition was changed as shown in Table 1, the rubber composition for the gasket and the gasket of Comparative Example 4 were manufactured in the same manner as in Example 1.

Specifically, in the case of Comparative Example 4, in which two types of EPDM-based rubber are mixed without the use of chlorinated polyethylene resin and then inorganic fillers, flame retardants, expanded graphite, process oil, and additives are added, they are blended with neoprene and combined with a flame retardant. It was confirmed that there was an effect of improving flame retardancy and extrudability, but the thermal expansion of expanded graphite was somewhat reduced, resulting in a negative effect on volume expansion during combustion.

[Comparative Example 5]

Except that the composition was changed as shown in Table 1, the rubber composition for the gasket and the gasket of Comparative Example 5 were manufactured in the same manner as Example 1.

Specifically, in the case of Comparative Example 5, in which two types of EPDM-based rubber were mixed without the use of neoprene-based rubber and then inorganic fillers, flame retardants, expanded graphite, process oil, and additives were added, the extrusion processability was good, but the flame retardancy was good. When judging mainly on physical properties, it was confirmed to be the lowest among all comparison subjects.

[Experimental Example 1. Physical property evaluation (1)]

The physical properties of gasket specimens manufactured using the rubber compositions of Examples 1 to 2 and Comparative Examples 1 to 5 were analyzed as follows.

The test methods and results used at this time are shown in Tables 3 and 4, respectively.

Test methods and evaluation standards Flame retardant Determination is made by directly burning the cross section of the extruded specimen with a torch for 2 minutes and then measuring the degree and time of digestion of the specimen. ○: No flame after direct combustion.
△: Flame generation after direct combustion (flame duration: 10 seconds or less)
Х: Flame generation after direct combustion (flame duration: more than 10 seconds, less than 30 seconds) extrusion
Processability After assembling the mold of the extruder, the surfaces of the discharged products are visually compared to each other and determined as follows. ○: The shape and surface of the product are smooth and the discharge performance is smooth.
△: The product shape has a rough surface and good discharge properties.
Х: The shape of the product is not properly formed and the bonding strength is reduced. Graphite extensibility After measuring the initial thickness of the extruded specimen, the cross-section of the specimen was directly heated with a torch for 2 minutes, and then the volumetric expansion of the specimen was measured and determined as follows. ○: Expansion of more than 3 times (≥ 300%) compared to the initial thickness of the specimen
△: Expansion of 1.5 to 2 times (150 to 200%) compared to the initial thickness of the specimen.
Х: Expansion less than 1.5 times (≤150%) compared to the initial thickness of the specimen

Example 1 Example 2 Comparative example
One Comparative example
2 Comparative example
3 Comparative example
4 Comparative example
5 Flame retardant ○ ○ × × △ △ × Extrusion processability ○ ○ △ ○ × ○ ○ Graphite extensibility ○ △ △ △ △ △ ×

As shown in Table 4 above, in the case of the specimens of Comparative Examples 1 to 5 that did not contain the essential components of the present invention, extrusion workability and bonding strength were reduced, making continuous extrusion difficult during the extrusion process, and the extruded product Since the surface was also unsatisfactory, we had no choice but to lower the flame retardancy. In contrast, it was confirmed that the specimen of Example 1-2, which had a composition optimized for a predetermined mix, had excellent processability, bondability, and high flame retardancy at the same time.

[Experimental Example 2. Flame retardancy determination]

The flame retardancy of the gasket specimen manufactured using the rubber composition of Example 1 was determined as follows.

The flame retardancy evaluation of the specimen was conducted at the Korea Testing and Research Institute (KTR), and the test method used and the results are shown in Figures 1 to 5 below.

As shown in Figures 1 to 5 below, it was confirmed that the specimen of Example 1 of the present invention optimized with a predetermined mixture not only secured high flame retardancy, but was also environmentally friendly and had excellent processability and bondability. Accordingly, it was found that it can be usefully applied as a flame retardant expansion gasket that maintains airtightness between aluminum windows, sash and glass, and also prevents the spread of flame and harmful gases through thermal expansion in the event of a fire.

Claims (18)

Ethylene-propylene-diene (EPDM)-based rubber;
Neoprene-based rubber;
Chlorinated polyolefin resin;
inorganic filler;
flame retardants; and
Contains process oil,
A rubber composition for a gasket comprising 5 to 15 parts by weight of expanded graphite based on 100 parts by weight of the composition. According to paragraph 1,
The expanded graphite expands 100 to 300 times when heated to 150°C or higher, and has a particle size of 60 to 300 mesh and a carbon component of 95% by weight or more. According to paragraph 1,
The ethylene-propylene-diene (EPDM)-based rubber includes at least three types,
Non-oil-containing first ethylene-propylene-diene rubber;
Non-oil-containing second ethylene-propylene-diene rubber; and
A rubber composition for a gasket comprising an oil-containing tertiary ethylene-propylene-diene rubber. According to paragraph 3,
The first ethylene-propylene-diene rubber has a Mooney viscosity (ML1+4, 125°C) of 15 to 35, an ENB (ethylidene norbornene) content of 4.5 to 12% by weight, and ethylene (ethylene). The content is 50 to 80% by weight,
The second ethylene-propylene-diene rubber has a Mooney viscosity (ML1+4, 125°C) of 45 to 65, an ENB (ethylidene norbornene) content of 4.5 to 12% by weight, and ethylene (ethylene). A rubber composition for a gasket having a content of 50 to 80% by weight. According to paragraph 3,
The third ethylene-propylene-diene rubber has a Mooney viscosity (ML1+4, 125°C) of 40 to 70, an ENB (ethylidene norbornene) content of 3.0 to 10% by weight, and ethylene (ethylene). A rubber composition for a gasket having a content of 60 to 90% by weight. According to paragraph 3,
The mixing ratio of the first ethylene-propylene-diene-based rubber, the second ethylene-propylene-diene-based rubber, and the third ethylene-propylene-diene-based rubber is 4 to 6: 0.3 to 2.5: 3 to 5 weight ratio. , Rubber composition for gaskets. According to paragraph 1,
The neoprene rubber is a rubber composition for a gasket having a Mooney Viscosity (ML1+4) of 35 to 55. According to paragraph 1,
The rubber composition for a gasket, wherein the chlorinated polyolefin resin includes at least one chlorinated polyethylene resin having a chlorination degree of 5 to 40% by weight. According to paragraph 1,
The inorganic fillers include calcium carbonate (CaCO ₃ ), talc, magnesium carbonate, clay, talc, barium sulfate, silica, mica, titanium oxide, carbon black, graphite, carbon nanotubes, graphite, wollastonite, and A rubber composition for a gasket that is at least one selected from the group consisting of nano silver. According to paragraph 1,
The flame retardant may include a metal hydroxide-based first flame retardant; Antimony-based secondary flame retardant; Halogen-based third flame retardant; A rubber composition for a gasket comprising at least one of the following. According to clause 10,
A rubber composition for a gasket, wherein the metal hydroxide-based first flame retardant is at least one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, and potassium hydroxide. According to clause 10,
A rubber composition for a gasket, wherein the halogen-based third flame retardant is at least one selected from the group consisting of decabromine and chlorinated paraffin. According to clause 10,
The rubber composition for a gasket wherein the first flame retardant, the second flame retardant, and the third flame retardant are used in a weight ratio of 50 to 90:3 to 20:7 to 30. According to paragraph 1,
A rubber composition for a gasket, wherein the process oil is at least one of paraffin-based or naphthenic oil. According to paragraph 1,
Based on 100 parts by weight of the composition,
20 to 50 parts by weight of ethylene-propylene-diene (EPDM)-based rubber;
1 to 15 parts by weight of neoprene-based rubber;
1 to 15 parts by weight of chlorinated polyolefin resin;
3 to 30 parts by weight of inorganic filler;
20 to 60 parts by weight of flame retardant;
5 to 15 parts by weight of expanded graphite; and
A rubber composition for a gasket comprising 1 to 20 parts by weight of process oil. According to paragraph 1,
The composition is one selected from the group consisting of pigments, colorants, moisture absorbents, slip agents, antioxidants, lubricants, anti-aging agents, foaming agents, cross-linking agents, cross-linking aids, processing aids, vulcanizing agents, binders, coupling agents, heat stabilizers, and UV stabilizers. A rubber composition for a gasket further comprising one or more additives. A flame retardant expansion gasket using the gasket rubber composition according to any one of claims 1 to 16. According to clause 17,
Flame retardant expansion gasket applied to at least one of fire doors, windows, sashes, and glass.

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