JPS6136790B2 - - Google Patents

Description

[Detailed description of the invention]

[] Object of the Invention The present invention relates to a chlorinated polyethylene composition that is based on chlorinated polyethylene and has good electrical conductivity and excellent flame retardancy. More specifically, the present invention relates to a chlorinated polyethylene composition comprising chlorinated polyethylene, carbon black, a chlorine-containing organic compound, antimony oxide, and a hydrous inorganic compound. [] Background of the Invention Rubber compositions having electrical conductivity are widely used as antistatic materials for electrical materials such as switches or connectors of electrical appliances, heating elements, and packaging materials. Many types of conductive rubber compositions are known, which are generally obtained by adding a conductive substance (for example, carbon black, metal powder, conductive polymer) to various rubbers. however,
Metal powder has a high specific gravity, so when adding metal powder to obtain a rubber composition with excellent electrical conductivity, mechanical properties (for example, tensile strength) will decrease due to the addition of a large amount of metal powder. Not practical. From the above, many conductive rubber compositions are made by adding carbon black (eg, acetylene black, conductive furnace black) to rubber. However, in order to incorporate carbon black into rubber and impart sufficient electrical conductivity, a considerable amount of carbon black must be incorporated. For example, to reduce the volume resistivity of rubber (for example, styrene-butadiene rubber) to 10 ⁵ Ω・cm or less, carbon black is added to 100 parts by weight of rubber.
Approximately 100 parts by weight must be blended. The reality is that when a large amount of carbon black is blended in order to improve electrical conductivity, not only does moldability deteriorate, but the resulting molded product does not have mechanical properties that can withstand practical use. Further, as described above, many of the conductive rubber compositions contain a large amount of carbon black, so it is very difficult to impart flame retardancy to them. on the other hand,
In order to impart only flame retardancy to rubber without imparting electrical conductivity, a commonly used flame retardant consisting of a halogen-containing organic compound (for example, chlorinated paraffin) and antimony trioxide is blended. It is well known that this can be achieved by However, it is very difficult to impart flame retardancy to conductive rubber compositions. The reason for this is that even if flame retardance is imparted by adding, for example, halogen-containing organic compounds and antimony trioxide, the actual flame retardant test (Underwriters Laboratories, Bretan 94, USA, hereinafter referred to as UL-94 method) When exposed to a flame, the carbon black chars and glows violently, leaving a lingering flame that lingers and ignites when it comes in contact with other combustible materials. Furthermore, even if a considerable amount of flame retardant is added, the same tendency as above does not disappear, and it is difficult to compensate for the drawbacks. Furthermore, even if flame retardance can be imparted to a conductive rubber composition by adding a considerable amount of flame retardant, the electrical conductivity of the rubber decreases due to, for example, a decrease in the blending ratio of carbon black. Therefore, it is impossible to obtain a rubber composition that has good electrical conductivity and excellent flame retardancy. Furthermore, since a large amount of an expensive flame retardant is used, the composition is not only expensive, but also has the drawback that the molded product thereof does not have mechanical properties that can withstand practical use. [] Constitution of the Invention From the above, the present inventors have discovered that chlorinated polyethylene has the characteristics of high loading property and halogen-containing polymer (rubber). As a result of various searches to obtain a chlorinated polyethylene composition that does not have the disadvantages of (A) 30 to 200 parts by weight of carbon black, (C) halogen-containing organic A chlorinated polyethylene composition comprising a total of 5 to 30 parts by weight of the compound and antimony oxide and (D) at least 5 parts by weight of a hydrous inorganic substance based on 100 parts by weight of the carbon black not only has good electrical conductivity but also They discovered that it also has excellent flame retardancy, and arrived at the present invention. [] Effects of the Invention The composition of the present invention not only has the effects (characteristics) as described above, but also has the following effects despite containing a large amount of carbon black etc. (high loading). are doing. (1) Excellent formability (2) Good mechanical strength (e.g. tensile strength, tear strength). By crosslinking, mechanical strength can be further improved. (3) Excellent flexibility. (4) Good workability (for example, processability). [] Detailed description of the invention (A) Chlorinated polyethylene The chlorinated polyethylene used in the present invention is obtained by chlorinating polyethylene powder or particles in an aqueous suspension, or by chlorinating polyethylene dissolved in an organic solvent. (preferably by chlorination in aqueous suspension). In general, amorphous or crystalline chlorinated polyethylene with a chlorine content of 20 to 50% by weight is preferred, and amorphous chlorinated polyethylene with a chlorine content of 25 to 45% by weight is particularly preferred. The polyethylene is obtained by homopolymerizing ethylene or copolymerizing ethylene with at most 10% by weight of α-olefin (generally having at most 6 carbon atoms). Its density is generally between 0.910 and 0.970 g/cc.
Moreover, its molecular weight is 50,000 to 700,000. In producing the composition of the present invention, only chlorinated polyethylene may be used, but other types of polymeric substances that are miscible with chlorinated polyethylene may also be blended. The polymeric substances include ethylene-propylene-diene ternary copolymer rubber (EPDM), natural rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, styrene-butadiene copolymer rubber (SBR), Examples include rubbers such as acrylonitrile-butadiene copolymer rubbers (NBR) and butadiene homopolymer rubbers [generally having a Mooney viscosity (ML ₁₊₄ ) of 10 to 150]. In addition, other polymeric substances include the above-mentioned polyethylene, vinyl chloride resin containing vinyl chloride as the main component (degree of polymerization, 400-1800), methyl methacrylate resin containing methyl methacrylate as the main component, and acrylonitrile-styrene copolymer resin. Examples include resin-like substances such as. These rubber-like and resin-like materials are described in the "Synthetic Rubber Handbook" edited by Kambara et al. (Asakura Shoten, published in 1962), the "Plastic Handbook" edited by Murahashi et al. (Asakura Shoten, published in 1968), etc. It is well known. When these polymeric substances are blended, the blending ratio is at most 50 parts by weight based on the chlorinated polyethylene. (B) Carbon black Furthermore, the carbon black used in the present invention generally has a specific surface area of 20 to 1800 as measured by low temperature nitrogen adsorption method and BET method.
m ² /g and pore volume are 1.5 to 4.0 as measured by mercury intrusion method in the pore radius range of 30 to 7500 A°.
cc/g. Examples of the carbon black include channel black, acetylene black, rubber compounded carbon black manufactured by the furnace black method, and other conductive carbon blacks. Regarding these carbon blacks, please refer to "Carbon Black Handbook" (edited by Carbon Black Association) (Tosho Publishing Co., Ltd., published in 1972), "Handbook of Carbon Black" (edited by Rubber Digest Co., Ltd.),
Their manufacturing methods and physical properties are well known from publications such as "Plastic Compounded Chemicals" (Rubber Digest Co., published in 1972) and the aforementioned "Synthetic Rubber Handbook". Among these carbon blacks, Conductive carbon black (generally has a specific surface area of 600~
1200 m ² /g) is suitable because it has a large effect of imparting electrical conductivity to chlorinated polyethylene and can impart high electrical conductivity to chlorinated polyethylene with a relatively small amount. (C) Halogen-containing organic compound and antimony oxide (1) Halogen-containing organic compound The halogen-containing organic compound used in the present invention is widely known as a flame retardant. Representative examples include tetrachlorophthalic anhydride, chlorinated paraffin, chlorinated bisphenol A, brominated bisphenol S,
Chlorinated diphenyl, brominated diphenyl,
Mention may be made of chlorinated naphthalenes, tris(β-chloroethyl) phosphate and tris(dibromobutyl) phosphate. (2) Antimony oxide Furthermore, the antimony oxide used in the present invention is generally used as a flame retardant aid for the halogen-containing organic compound. Representative examples include antimony trioxide and antimony pentoxide. These halogen-containing organic compounds and antimony oxide are well known from the above-mentioned "Handbook of Chemicals Compounded with Rubber and Plastics." (D) Water-containing inorganic substance The water-containing inorganic substance used in the present invention contains 10 to 80% by weight of bound water and has a true specific gravity of 1.0 to 5.0. Typical examples of hydrated inorganic substances are hydrates of metals of Groups A, B, and B of the periodic table and salts containing these metals. The hydrated inorganic substances include magnesium hydroxide, calcium hydroxide, aluminum hydroxide (Al ₂ O ₃ · nH ₂ O), hydrated gypsum, kaholin clay, calcium carbonate, hydrotalcite, basic magnesium carbonate, and boric acid. Examples include compounds that have water in their molecules, such as magnesium and precipitated barium sulfate. These water-containing inorganic substances are poorly soluble in water, and 100
The solubility of cc in water at a temperature of 20℃ is
Generally, the amount is 10 g or less, preferably 1 g or less, and particularly preferably 0.1 g or less. Suitable hydrous inorganic substances include aluminum hydroxide,
Mention may be made of hydrated gypsum, magnesium hydroxide, calcium carbonate, basic magnesium carbonate, precipitated magnesium sulfate and calcium. (E) Blending ratio (mixing ratio) The blending ratio of carbon black to 100 parts by weight of chlorinated polyethylene is 30 to 200 parts by weight, preferably 40 to 180 parts by weight, particularly 50 to 150 parts by weight.
Parts by weight are preferred. Further, the blending ratio of the halogen-containing organic compound and antimony oxide to 100 parts by weight of chlorinated polyethylene is 5 to 30 parts by weight in total, preferably 10 to 30 parts by weight, and particularly preferably 10 to 25 parts by weight. be. The blending ratio of antimony oxide to the amount of halogen element in 100 parts by weight of a halogen-containing organic compound is generally
100 to 600 parts by weight, preferably 100 to 400 parts by weight, especially from the viewpoint of flame retardancy and bleedability.
150 to 400 parts by weight are preferred. The important point of the present invention is that in addition to the usual flame retardant formulation consisting of carbon black and ordinary flame retardants (halogen-containing organic compounds and antimony oxide), it has good electrical conductivity and is highly flame retardant (UL-944). In order to impart V-O), at least 5 parts by weight of a water-containing inorganic substance is added to 100 parts by weight of the carbon black, preferably 7 to 20 parts by weight. In producing the composition of the present invention, chlorinated polyethylene, carbon black, halogen-containing organic compound, antimony oxide, and hydrated inorganic substance may be used alone or in combination of two or more. (F) Mixing method, molding method, etc. Although the composition of the present invention can be obtained by uniformly blending the above substances, fillers and plasticizers commonly used in the rubber and resin industries are also added. Additives such as oxygen, ozone, heat and light (ultraviolet) stabilizers, lubricants and colorants may be added depending on the intended use of the composition. In addition, sulfur vulcanizing agents, sulfur-releasing compound-based vulcanizing agents, amine-based vulcanizing agents, organic peroxide-based crosslinking agents and organic peroxide-based crosslinking co-agents commonly used in the rubber and resin industries. Additives may be added depending on the intended use of the composition. When producing the composition of the present invention, the blending (mixing) method may be to use a mixer commonly used in the art such as an open roll, dry blender, Banbury mixer, and kneader. Among these mixing methods, in order to obtain a more uniform composition, two or more of these mixing methods may be applied (for example, after mixing in advance with a dry blender, the mixture may be mixed using an open roll. how to). In producing the composition of the present invention, all the ingredients may be mixed at the same time, but some of the ingredients may be mixed in advance and then other ingredients may be mixed into the resulting mixture ( For example, a method in which chlorinated polyethylene, a halogen-containing organic compound, antimony oxide, and a water-containing inorganic substance are mixed in advance, and then the resulting mixture is mixed with carbon black). The composition of the present invention may be molded into a desired shape using a molding machine commonly used in the rubber industry, such as an extrusion molding machine, an injection molding machine, a compression molding machine, or a calendar molding machine. In addition, a method of manufacturing a molded product while vulcanizing (crosslinking) it by adding chlorinated polyethylene or the above-mentioned composition and vulcanizing (crosslinking) it in the rubber technology field, that is, a method of simultaneously proceeding vulcanization and molding, is applied. It may be formed into a desired shape. The composition of the present invention not only has high flame retardancy as described above, but also high electrical conductivity (10 ³ Ω·cm or less). Furthermore, the brittleness, hardness, and mechanical properties of commonly used conductive rubber moldings have been significantly improved.
From these points, the composition of the present invention has extremely great practical value. [] Examples and Comparative Examples The present invention will be explained in more detail below using Examples. In addition, in Examples and Comparative Examples, "parts" are based on weight. The flame retardancy test was measured according to the UL-94 method. The specimens used were 1/16 inch thick, 5 inches long, and 1/2 inch wide. In addition, the volume resistivity test is performed using a resistance meter (manufactured by Takeda Riken Co., Ltd., product name: Digital Multimeter).
TR-6856), the resistance of the test piece was measured using a test piece with a thickness of 2 mm in an atmosphere of a temperature of 25° C. and a humidity of 60%, and was calculated according to the following formula. Volume resistivity (Ω·cm)=S×R/t Here, S is the electrode area of the specific resistivity measuring electrode, R is the resistance value of the specimen, and t represents the thickness of the specimen. In addition, in the bending test, a sheet with a thickness of 2 mm, a width of 10 mm, and a length of 100 mm was wrapped around a cylinder (diameter 10 mm), and the cracks on the surface observed with the naked eye were ranked into three levels according to the following criteria. Shown. Rank Degree of surface cracks 〇 No cracks at all △ Slight cracks × Large cracks and cracks Examples 1 to 5, Comparative Examples 1 to 5 Ethylene-butene-1 containing 3.0% by weight of butene-1 A copolymer (density 0.950 g/cc, average molecular weight approximately 200,000) is chlorinated in an aqueous suspension to produce amorphous chlorinated polyethylene [chlorine content 31.5% by weight, Mooney viscosity (ML ₁₊₄ ) 120 , hereinafter referred to as "CPE"]
was manufactured. CPE, styrene produced as above
Butadiene copolymer rubber (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name Solprene 1206, styrene content 20% by weight, Mooney viscosity (ML ₁₊₄ ) 60, hereinafter referred to as "SBR"), or chloroprone rubber (manufactured by Showa Neoprene Co., Ltd., Product name: Neoprene, W, Mooney viscosity (ML ₁₊₄ )
47, hereinafter referred to as "CR"] or a mixture thereof (the amounts are shown in Table 1-1), tribasic lead sulfate.
10 parts by weight, 5 parts by weight of chlorinated paraffin (not added in Comparative Example 1), antimony trioxide (hereinafter referred to as "Sb ₂ O ₃ ", the amount of which is shown in Table 1-1), Alumina trihydrate having a crystal structure (true density 2.42 g/cc, particle size 3 to 20 microns, hereinafter referred to as "Al ₂ O ₃ 3H ₂ O"), the blending amount is
Furnace Black (as shown in Table 1), average particle size of approximately 30 millimeters, manufactured by Cabot Co., Ltd., trade name Vulcan XC-72, density approximately 1.8 g/cc,
surface area 220 m ² /g, hereinafter referred to as "C-1", the amount of compounding is shown in Table 1-1], triallyl isocyanurate (hereinafter referred to as "TAIC", the amount of compounding is shown in Table 1-1)
) and 2,5-di-methyl-2,5-
Di-(tertiary-butylperoxy)hexane (hereinafter referred to as "peroxide", the amount of compounding is shown in Table 1-1) was heated for 20 minutes using an open roll whose surface temperature was set in advance to 50℃. The mixture was kneaded and formed into a sheet. Among the sheets obtained as described above, some of the sheets were pressed for 5 minutes at a temperature of 70°C and a pressure of 100 kg/cm ² to create a sheet (Example 1,
2, Comparative Examples 1, 2, 4 to 6). Other sheets obtained by the above kneading were pressed for 10 minutes at a temperature of 180°C and a pressure of 100 kg/cm ² to create crosslinked sheets (Examples 3 to 5,
Comparative Example 3). The sheets obtained by pressing or crosslinking as described above were subjected to flame retardancy tests, resistance measurements, and bending tests. The results are shown in Table 1-2.

【table】

[Table] Examples 6 to 10, Comparative Examples 7 to 11 Instead of C-1 used as the carbon black in Examples 1 to 5 and Comparative Examples 1 to 6, Ketschen Black (manufactured by Akzo Chemie, Netherlands, product) was used as carbon black. Famous emblem black, density 1.8g/cc,
The surface area was 1195 m ² /g, hereinafter referred to as "C-2"], and the blending amounts of the other ingredients were changed as shown in Table 2-1, but the conditions were the same as in Example 1. and created a sheet for each. Among the sheets obtained as described above, some sheets were pressed in the same manner as in Example 1 to create sheets (Examples 6 and 7, Comparative Examples 7, 8, 10,
11). Other sheets obtained by the above kneading were crosslinked in the same manner as in Example 3 to create sheets (Examples 8 to 10, Comparative Example 9). The physical properties of each sheet obtained by pressing or crosslinking as described above were measured. The results are shown in Table 2-2.

【table】

[Table] Examples 11 to 15, Comparative Examples 12 to 16 Instead of C-1 used as carbon black in Examples 1 to 5 and Comparative Examples 1 to 6, carbon fiber (manufactured by Nihon Kynor Co., Ltd., trade name Kynor 16BT) was used as the carbon black. , hereinafter referred to as "C-3"),
Kneading was carried out in the same manner as in Example 1, except that the amounts of the other ingredients were changed as shown in Table 3-1.
I created a sheet for each. The sheet obtained as described above was pressed in the same manner as in Example 1 to create a sheet. The physical properties of each sheet obtained were measured. The results are shown in Table 3-2.

【table】

【table】

[Table] Examples 16 to 19 Magnesium hydroxide [particle size 0.2 to 5 microns, surface area 1.45 m ² /g, Mg(OH) ₂ ], hydrated instead of the alumina trihydrate used in the examples Gypsum [particle size 0.2-5 microns, surface area 1.50 m ² /g,
CaSO ₄ 2H ₂ O], calcium carbonate (particle size 1.7 microns, surface area 1.78 m ² /g, CaCO ₃ ) and basic magnesium carbonate [particle size 5 microns or less, surface area 6
A sheet was prepared by kneading in the same manner as in Example 1, except that 15 parts by weight _{of each of 9 m 2} ^/ g Mg ₄ (OH) ₂ (CO ₃ ) 3.3H ₂ O] was added. Each of the obtained sheets was pressed under the same conditions as in Example 1 to create a sheet. When the flame retardancy test of each sheet obtained was conducted, it was found to be V-0, and when a bending test was conducted, no cracks appeared on the surface of any of the sheets. Table 4 shows the volume resistivity of each sheet.

[Table] Examples 20 to 23 Instead of the chlorinated paraffin used as the halogen-containing organic compound in Example 1, chlorinated polyphenyl, chlorinated diphenyl, brominated polyphenyl, and tris(β-chloroethyl) phosphate [hereinafter referred to as "compound ( A sheet was prepared by kneading in the same manner as in Example 1, except that 5 parts by weight of each of A) were added. Each of the obtained sheets was pressed under the same conditions as in Example 1 to produce a sheet.
When the obtained sheets were subjected to a low solubility test, they were found to be V-0. A bending test was also conducted, and no cracks appeared on the surface of any of the samples. Table 5 shows the volume resistivity of each sheet.

[Table] From the above Examples and Comparative Examples, the composition of the present invention not only has superior flame retardancy compared to styrene-butadiene copolymer rubber and chloroprene rubber, but also shows no cracking in the bending test. It is clear that there is no problem (that is, there is excellent flexibility). Furthermore, it is clear that the composition of the present invention has excellent electrical conductivity and flame retardancy, with both properties being well balanced.

Claims (1)

[Scope of Claims] 1 (A) based on 100 parts by weight of chlorinated polyethylene, (B) 30 to 200 parts by weight of carbon black, (C) a total of 5 to 30 parts by weight of a halogen-containing organic compound and antimony oxide, and (D) A chlorinated polyethylene composition comprising at least 5 parts by weight of a hydrous inorganic substance based on 100 parts by weight of the carbon black.