JPS6142937B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition that contains expandable graphite and has excellent fire resistance due to foaming action, as well as excellent moldability, mechanical properties, flexibility, water resistance, cold resistance, and fire resistance. In recent years, with the development of petrochemistry, many types of synthetic polymers have been widely used as interior materials for buildings, vehicles, etc., electrical and thermal insulation materials, and the like. However, these synthetic polymers are generally flammable, and therefore fires in buildings, vehicles, etc. tend to become large-scale and cause catastrophes. In addition, the insulation of the cables attached to fire prevention equipment breaks down due to a fire, and as a result, the power transport function is lost, making the fire prevention equipment ineffective and causing larger fires. Technology development has become a pressing issue. Recently, a fire protection paint composition containing expandable graphite has been developed, and when this paint is heated to a high temperature in the dry state of the paint, the expandable graphite expands and forms a heat insulating layer made of graphite. It has the effect of protecting protected objects from fire. However, known paints containing expandable graphite have a dry film with poor flexibility, and therefore, when applied to an object, the object may be deformed or bent, even temporarily, due to external force, etc. The paint film cracks and peels off partially. In particular, in the case of insulated cables, the cable undergoes several bends during manufacturing and installation, and even after installation, it is constantly deformed due to heat history, etc., so it is not recommended to protect it with the above-mentioned known paints. . A further important drawback of fire-protective paints is that they are not suitable for continuous production in factories of elongated bodies, such as insulated cables, pipes, having a layer of fire-protective compositions. The reason for this is that in order to form a fireproof composition layer using a paint, it is necessary to dry the paint, but this drying is extremely difficult to accomplish within a short period of time. The reason why the invention is directed to the development of moldable fire protection compositions is due in particular to the above-mentioned serious drawbacks of the known paints. By the way, the present inventors have discovered that only when expandable graphite and a specific polymer out of countless polymers are mixed in a specific quantitative ratio without using a liquid medium that is volatile at room temperature, The present invention was completed based on the discovery that it is possible to obtain a composition that does not have the disadvantages of the foamed fire protection paint and has excellent moldability. That is, the present invention comprises at least one type of chlorine-containing polymer selected from polyvinyl chloride and chlorinated polyethylene and expandable graphite, and the blending ratio is 10 to 150 parts by weight of expandable graphite per 100 parts by weight of the chlorine-containing polymer. The present invention relates to a foamed fire retardant composition. By the way, graphite has a structure in which carbon atoms are stacked in layers in a hexagonal network plane. In this layered structure, the bonds within the layer planes are very strong, but the bonds between the layer planes are weak, and relatively wide spaces remain between the layers, and under appropriate conditions, many types of compounds can form between the graphite layers. It is known that some graphite intercalation compounds are expanded by rapid heating and elongated in the C-axis direction. It is being The expandable graphite used in the present invention is such a graphite intercalation compound, and includes, for example, the following compounds. (1) Graphite acid sulfates obtained by anodizing graphite or coexisting with sulfuric acid under oxidizing conditions in the presence of nitric acid, chromic acid, potassium permanganate, manganese dioxide, perchloric acid, phosphoric acid, etc. Various inorganic acid salts (2) Sodium graphite (C ₆₄ Na), potash graphite (C ₈ K,
Various types of metallic graphite (C ₂₄ K, C ₃₆ K), etc. (3) Chlorinated graphite (C ₈ Cl) and bromine graphite (C ₈ Br) obtained by reacting graphite with halogen or halogen compounds at room temperature or higher temperatures. Various types of halogen graphite (4) such as graphite and certain metal halide compounds
Various metal halide graphitized compounds such as aluminum chloride graphitized products and ferric chloride graphitized products obtained by reacting at around ℃ (5) Graphite oxide (C ₃ O) obtained by forming covalent bonds with carbon atoms, Various carbon-covalent products such as graphite fluoride (CF). The detailed manufacturing method and properties of expandable graphite are described in detail in the following literature. 1 JP-A-54-38292 2 JP-A-52-109511 3 Published by Kanehara Publishing Co., Ltd., Chemistry of new industrial materials, Volume 8, Carbon and graphite products, Volume 49, 50,
pp. 101, 196, 199 4 Bericht d.Doutschen Chem Ges 24
(1891), p. 4085 5 Ibid. 63 (1930), p. 1249 6.
Allgemainen Hemy I (Zeitsschr f.
anorg.U.allgem.Chemie) 67 (1932), 340
Page 100℃ (preferably 150℃) of these expandable graphites
It is preferable to use a material that expands when heated above
10 times or more, preferably 40 times or more is used. The expandable graphite related to the present invention is generally fine to fine particles of 10 meshes or more, but
Preferably 20 to 100 meshes, more preferably
It is 40 to 80 meters. When the number of meshes exceeds 100, the foamability deteriorates, and when the number of meshes exceeds 10, the extrusion processability deteriorates. The amount of expandable graphite added is
The amount is 10 to 150 parts by weight, preferably 20 to 80 parts by weight, per 100 parts by weight. As described above, one of the characteristics of the composition of the present invention is that the amount of expandable graphite used is small and the chlorine-containing polymer is added in a large amount. Excellent flexibility, cold resistance, and foam fire resistance.
Therefore, a composition with excellent fire resistance is obtained. Moreover, each composition component is water resistant, so
The composition of the present invention also has excellent water resistance. If the amount of expandable graphite is 150 parts by weight or more, extrusion processability is improved.
Flexibility and cold resistance deteriorate, and conversely, if the amount is less than 10 parts by weight, foaming fireproofing properties deteriorate. The composition of the present invention uses at least one chlorine-containing polymer selected from polyvinyl chloride and chlorinated polyethylene as a polymer component, and this point is also one of the characteristics of the present invention. In other words, when using polymers other than these, such as polyethylene, a drip phenomenon occurs due to the high temperature during a fire before it can exert its fireproofing effect, and a sufficient fireproofing effect cannot be obtained. When polymers such as polychloroprene, chlorosulfonated polyethylene, polyepichlorohydrin, etc. are used, carbonization and foaming properties are poor, and therefore sufficient fireproofing effects cannot be obtained.
The chlorine content of the chlorinated polyethylene used in the present invention is usually 15 to 60% by weight, preferably 30 to 50% by weight. Polyvinyl chloride includes homopolymers of vinyl chloride, ethylene, vinyl acetate, etc.
Those containing other copolymerized components, such as vinyl chloride graftomers, but with a chlorine content of at least 15% by weight, may also be used. In the case of a homopolymer of vinyl chloride, it is preferable to soften it by adding a plasticizer, and the softening may be carried out using a conventional plasticizer in a conventional amount. Particularly preferred plasticizers are those known as flame-retardant plasticizers. Furthermore, the composition of the present invention does not use a liquid medium that is volatile at room temperature, has excellent extrudability, and has an extruded layer with excellent flexibility. In the composition of the present invention, fillers, plasticizers, anti-aging agents, which are usually added to rubbers, plastics, etc.
Pigments etc. may also be added. The composition of the present invention can be prepared by conventional methods such as rolling,
It is kneaded using a kneader such as a mixer, plasticator, or Banbury mixer, and then prepared by extrusion molding, injection molding, processing molding, calendering, or the like. Examples 1 to 3, Comparative Examples 1 to 6 The compositions of Examples 1 to 8 shown in Table 1 and the compositions of Comparative Examples 1 to 6 were mixed using two rolls. In Table 1, the amount of each component is shown in weight %. Each composition was tested according to the conditions shown in the extrusion process evaluation test method section below.
600VCV cable 3 x 3.5 mm ² (outer diameter 13.5 mm) was extruded coated to a thickness of 2 mm, and in addition to evaluating the extrusion processability at that time, the flexibility of the composition was evaluated using the obtained sample wire. The cold resistance, flame retardance, and non-drip properties of each composition were evaluated separately from the foaming fire resistance, water resistance, weather resistance, heat resistance, etc., and the results are shown in Table 1. The test method and evaluation criteria for each characteristic item are as described below.

【table】

[Table] [Test method for evaluating foaming fire retardant ability] Cut the sample wire to approximately 40 cm and hold it vertically. Use a Bunsen burner with an inner flame length of 40 mm and an outer flame length of 130 mm, so that the tip of the inner flame hits the lower end of the sample wire, and burn for 10 minutes. The foaming state and damage distance were observed, and the foaming fireproofing ability was tested according to the criteria shown in Table 2.

[Extrusion processability evaluation test method]

600VCV cable 3 x 3.5mm ² (outer diameter 13.5mm) and screw L/
Using an extruder with D: 15 and screw diameter: 50 mm, the extrusion was extruded to a thickness of 2 mm, and the extrusion conditions were ranked in 5 stages according to the criteria described below. In other words, those with substantially no variation in the discharge rate and the extruded coating having extremely good smoothness and gloss are excellent; Good, if the discharge rate fluctuates slightly but the smoothness is good, if the discharge rate fluctuates, it is difficult to extrude, and the smoothness is poor and the texture is rough, then the extrusion is difficult. What was possible was determined to be impossible. [Flexibility evaluation test method] Cut the sample wire to a length of about 50 mm and place it on a mandrel with an outer diameter of 12 cm, which is about 7 times the coating diameter, at room temperature.
Bending was repeatedly performed to determine the flexibility at that time and the number of times the extruded coating layer was bent until cracks appeared, and the flexibility was ranked in four stages according to the following criteria. In other words, those that have extremely good flexibility when bent and can be bent 70 times or more before cracks appear in the coating are considered excellent, and those that have good flexibility and can be bent 50 times or more are considered excellent. Good, those with poor flexibility and flexed 10 times or more were rated as acceptable, and those with very poor flexibility and flexed 9 or less times were rated poor. [Water resistance evaluation test method] Cut the sample wire to a length of about 70 cm, immerse it in a water tank controlled at 30°C with both ends sticking out above the water surface, leave it for 7 days, then take it out, dry it and see the above foaming. The foaming fire retardant ability was examined in accordance with the test method for evaluating fire retardant ability, and the water resistance was indicated based on the criteria shown in Table 3.

[Weather resistance evaluation test method]

Cut the sample wire to a length of about 30 cm and run it using a weather meter (Toyo Rika Kogyo WE-2) under the following conditions.
Type, light source; carbon arc (2 lights), temperature;
After 800 hours of exposure to a black panel thermometer at 60°C and a rainfall cycle of 120 minutes and 18 minutes of rain, the foaming fire-retardant ability was examined according to the above-mentioned foaming fire-retardant ability evaluation test method.
Weather resistance was expressed based on the criteria shown in the table. [Heat resistance evaluation test method] Cut the sample wire to a length of approximately 30 cm, leave it in a gear open temperature controlled at 70°C for 30 days, take it out, and test the foam fire retardant ability according to the above test method for evaluating foam fire retardant ability. Heat resistance was expressed based on the criteria shown in Table 3. [Cold resistance evaluation test method] The embrittlement temperature was measured according to JISK6723, and the cold resistance was expressed according to the criteria shown in the table below.

[Flame retardancy evaluation test method]

Oxygen index was measured according to JISK7201, and flame retardancy was indicated according to the criteria shown in the table below.

[Non-drip property evaluation test method]

A test piece with a thickness of 3 mm, width of 10 mm, and length of 150 mm is prepared and supported vertically. Set the flame length of the Bunsen burner to about 15 mm, place it so that the tip of the flame reaches the bottom edge of the test piece, and heat it for 1 minute. Items that do not continue to burn and melt and do not drip are acceptable. Items that continue to burn but melt and drip are not acceptable.

Claims (1)

[Claims] 1 Consists of at least one chlorine-containing polymer selected from polyvinyl chloride and chlorinated polyethylene and expandable graphite, the blending ratio of which is 100% of the chlorinated polymer.
A foamed fire protection composition having moldability of 10 to 150 parts by weight of expandable graphite. 2. The foamable composition according to claim 1, wherein the expandable graphite has a particle size of 20 to 100 mesh.