公开(公告)号：US4554173A

公开(公告)日：1985-11-19

申请号：US521115

申请日：1983-08-08

申请人： Syunichi Fujimura ,  Eisuke Oda ,  Miyuki Hagiwara ,  Youske Morita

发明人： Syunichi Fujimura ,  Eisuke Oda ,  Miyuki Hagiwara ,  Youske Morita

IPC分类号： B05D3/02 ,  B05D7/22 ,  H01B3/44 ,  H01B7/295 ,  H01B13/14 ,  B05D5/12

CPC分类号： H01B7/295 ,  B05D3/0254 ,  B05D7/20 ,  H01B3/441

摘要： A method for manufacturing a flame-retardant insulated wire and cable for use in nuclear power stations, comprises the steps of: extruding on a conductor or cable care to a predetermined thickness a composition consisting of 100 parts by weight of a basic polymer such as a thermoplastic resin or a rubber which can be crosslinked by an organic peroxide-based crosslinking agent, at least 10 parts by weight of a halogenated acenaphthylene or a condensate thereof, and 0.5 to 10 parts by weight of an organic peroxide; and heating a resultant wire or cable for crosslinking in the absence of water and at a temperature higher than the decomposition temperature of the organic peroxide.

摘要翻译： 一种制造用于核电站的阻燃绝缘电线电缆的方法，包括以下步骤：将导体或电缆护套挤出至预定厚度，该组合物由100重量份的碱性聚合物组成，例如 热塑性树脂或可通过有机过氧化物类交联剂交联的橡胶，至少10重量份卤化苊或其缩合物和0.5-10重量份有机过氧化物; 并加热所得的电线或电缆用于在不存在水的情况下和在高于有机过氧化物的分解温度的温度下进行交联。

公开(公告)号：US4065594A

公开(公告)日：1977-12-27

申请号：US470020

申请日：1974-05-15

申请人： Hikaru Shii ,  Eisuke Oda

发明人： Hikaru Shii ,  Eisuke Oda

IPC分类号： B29C33/00 ,  B29C43/00 ,  B29C43/24 ,  B29C55/18 ,  B29D7/00 ,  H01B13/10 ,  B29D7/14

CPC分类号： H01B13/103 ,  B29D7/00 ,  Y10S428/91 ,  Y10T428/24124

摘要： A method for preparing sheet-like, cord-like and other forms of product having excellent physical and chemical properties by mechanically pressing filmy or fibrous oriented materials of crystalline polyolefin, utilizing the pressure sensitivity of said materials.This invention relates to a method of preparing sheetlike, cord-like and other forms of polyolefin product having prominent physical and chemical properties and more particularly to a method of providing effective sheets for insulation of oil-filled power cables. Such insulation sheet is generally an oil-impregnated type whose main material is formed of pulp. However, such oil-impregnated insulation sheet which has a relatively large dielectric loss is not adapted for insulation of ultra-high voltage power cables. Recent tendency toward application of ultra-high voltage power cables demands an insulation material having a far less dielectric loss than has been allowed in the past. With ultra-high voltage cables, reduction of transmission loss requires the factors .epsilon. and tan .delta. of an insulation material to be minimized.Oil-impregnated insulation paper can be appreciably saved from dielectric loss by deionizing treatment, but under certain limitations. Namely, an attempt to reduce dielectric loss by digesting of pulp necessarily leads to the partial destruction of the cellulosic structure of the pulp and in consequence the fall of mechanical strength of insulation paper, though the factor tan .delta. of said insulation paper may be decreased. Therefore, this process is practically undesirable.From the above-mentioned point of view, an attempt has recently been made to use a synthetic fiber insulation sheet mainly formed of polyolefin and indicating an extremely small value of tan .delta.. However, polyolefin fiber raises problems not only with resistance to heat and oil demanded of such type of insulation material but also with the fabricating processes. A polyolefin fiber sheet is generally prepared by forming hot-drawn and fibrillated polyolefin fibers into a sheet by applying adhesive or by fusing said fibers under heat and pressure utilizing the thermal fusibility thereof. However, application of adhesive not only complicates the forming process and reduces the resistance to heat and oil and the electric properties of the adhesive used, though a good fibrous insulation sheet may be obtained, but also fails to improve the resistance to heat and oil of raw polyolefin itself. On the other hand, in the case of thermal fusion of polyolefin fibers, a high degree of thermal stretching of raw fibers causes thermal shrinkage during fabrication under heat and pressure and loss of dimensional stability, failing to provide a desired product. Though thermal fusion under high pressure may eliminate noticeable thermal shrinkage, a product obtained can not be released from pressure until it is fully cooled, with the resultant fall of productivity. Moreover, a product thus prepared generally takes the form of solid film presenting too large oil flow resistance to be used as insulation material for oil-filled power cables.Increase of the molecular weight or cross linking of polyolefin can indeed somewhat improve resistance to heat and oil but decreases the workability of polyolefin.It is accordingly the object of this invention to provide a method of preparing an insulation material free from the defects of prior art product simply by applying mechanical pressure, without using any adhesive or thermal fusion.The present inventors have studied the relationship between the fine structure and the physical properties of crystalline polyolefin and discovered that oriented materials of polyolefin having the later described particular fine structure have pressure sensitivity. This invention has been accomplished by said discovery to provide a method of preparing insulation material firmly formed into an integral mass simply by applying mechanical pressure.The appended drawing presents the melting curve of polyolefin as measured by differential scanning calorimeter (hereinafter abbreviated as "DSC"), showing the melting behavior of oriented materials of polyolefin used in the method of this invention.The raw oriented materials of polyolefin used in the method of this invention should meet the following three requirements:a. The oriented material presents a prominent superheated state when thermally melted. In other words, "K" (explained below) determined from the melting curve obtained by DSC is smaller than 70% or preferably 60%.b. The value of the long period "L" determined from the scattering intensity curve obtained by measuring small angle X-ray scattering is larger than 350 A, or preferably 500 A.c. The oriented material has a higher crystallinity "C" than 70% or preferably 80%.It should be noted that the values of K, L and C are determined by the following processes respectively:K: The melting curve of the oriented materials of crystalline polyolefin used in the present invention determined by DSC shows a form indicated by 1 in FIG. 1. When measured again after cooling the sample, the melting curve presents a form indicated by 3. A base line 2 is drawn below the curve 1 and an area defined by the curve 1 and the base line 2 is designated as S. A temperature represented by the peak point of the curve 3 is indicated by T.sub.1. That portion of the above-mentioned area S which corresponds to a lower temperature than T.sub.1 is denoted by S.sub.1. Then K is expressed by the following equation:K = S.sub.1 /S .times. 100determination by DSC was carried out under the condition in which samples weighing 3 to 10mg were tested with the heating rate set at 5 to 15 .degree. C/min.L: The long period L is calculated by applying the Bragg's equation to the peak point of the scattering intensity curve obtained by measuring small angle X-ray scattering. This measurement was carried out under the following conditions:X-ray source: Roterflex RU-3 made by Rigaku Denki Co., Ltd.Target: CopperTube voltage: 50 KVTube current: 80 mAFocus: Point focusFilter: NiSmall angle X-ray scattering apparatus: Manufactured by Rigaku Denki Co., Ltd.1st slit: 0.1 .times. 112nd slit: 0.05 .times. 11Counting slits: 0.1 .times. 11 and 0.02 .times. 15Scanning rate: 4'/minCounter: Proportional counterMeasuring Temperature: Room temperatureC: The density of the oriented materials of polyolefin used in the present invention is measured at 30.degree. C using a density gradient tube. The crystallinity of said materials is calculated by the following equation:1/.rho. = (1 - .OMEGA..sup.c)/.rho..sub.a + .OMEGA..sup.c /.rho..sub.cwhere:.rho..sub.a = density of amorphous region of the polyolefin.rho..sub.c = density of crystalline region of the same.OMEGA..sup.c = crystallinity.rho. = density being measuredAs mentioned above, the first requirement of the oriented materials of polyolefin used in the method of this invention is that K is smaller than 70%. However, the formability of the oriented materials into integral mass is not merely governed by K but by L and C as well. In case L is smaller than 350 A even when K is smaller than 70% or in case C is smaller than 70% even when K is smaller than 70% and L is larger than 350 A, the oriented materials will not be made into integrated mass at a lower level than the thermal distortion temperature and not have prominent resistance to heat and oil.After all, the oriented materials of polyolefin which meet the above-mentioned requirements for K, L and C at the same time can be made adaptable for use in the method of this invention.Accordingly, the raw films or fibers that meet the above three requirements, used in the method of this invention are prepared from crystalline polyolefin such as polyethylene, isotactic polypropylene, polybutene-1 and poly-4-methyl-pentene-1. As used herein, the term "oriented materials of polyolefin" includes split-yarns obtained from films, monofilaments, and fibers prepared by cutting said monofilaments or split-yarns into short pieces.The above-mentioned oriented materials of polyolefin are easily provided by the present inventors' process set forth in their U.S. Pat. No. 3,823,210. Said process consists of first forming polyolefin film by extrusion, drawing said film to a considerable extent in the direction of extrusion at as low temperature as possible, applying a tensile stress to a uniaxially stretched film thus obtained and, under this condition, extracting soluble fractions from said film in a solvent for polyolefin at a temperature close to the dissolution temperature.The raw oriented materials of polyolefin according to this invention are characterized in that they can be easily made into a desired integral product simply by applying mechanical pressure without adhesive or heat as is the case with the prior art in which highly oriented materials are made by hot drawing. Accordingly, the product of this invention truthfully displays the properties of the raw oriented materials of polyolefin, namely, prominent resistance to oil and heat, high dimensional stability and excellent electrical properties.The oriented materials of polyolefin according to this invention are characterized in that the small-angle X-ray scattering pattern presents discrete scattering on the meridium arising from an extremely large value of long period L and also intense diffuse scattering on the equator due to fibrillation of the oriented materials. Referring to the latter type of scattering, the intensity of diffuse scattering at an angle corresponding to the peak intensity on the meridium (namely, a vertical direction of the pattern) and at the same angle on the equator (namely, in a horizontal direction of the pattern) is 60 to 120% of the intensity of discrete diffraction.The oriented materials of polyolefin usable in the method of this invention have a tensile strength generally ranging from 5 to 10 (g/d), or about twice that of the prior art polyolefin films or fibers. K determined by DSC makes little difference whether before or after the mechanical pressure is applied according to the method of this invention. This holds true with C. However, L after application of mechanical pressure often cannot be observed between the fine structure is changed by the pressure.The above-mentioned mechanical pressure is applied by pressing a mass of raw oriented films or fibers made into a desired form against the surface of, for example, metal material. When a sheet-like product is manufactured, the raw oriented materials are superposed in the direction of orientation, arranged in parallel or at right angles to each other or at random, and thereafter subjected to rolling or press work, for example, on rolls used in ordinary metal work or emboss rolls. When a cord-like product is formed, the raw oriented materials are aligned in the direction of orientation and squeezed through a drawing die.If the pressing surface of, for example, rolls is fitted or coated with buffer material such as, cloth, paper, rubber, plastic sheet or film, then uniform pressure can be applied to the work, thus offering advantage in preparing a sheet-like product.Mechanical pressure applied in manufacturing the product of this invention is generally chosen to range between 50 and 1000 kg/cm.sup.2 or preferably between 500 and 800 kg/cm.sup.2.When a mechanical pressure is applied within the above specified range, the rate of reduction in the thickness or diameter of the shaped materials falls within the range of 5 to 50%. The apparent density of the product of this invention thus prepared ranges in almost all cases between the density of crystalline region of polyolefin and 40% of the density of the amorphous region thereof. Said apparent density falls within the range of 0.342 to 1.00 for high density polyethylene, 0.340 to 0.938 for isotactic polypropylene, 0.348 to 0.95 for polybutene-1 and 0.335 to 0.813 for poly-4-methylpentene-1.Though mechanical pressure according to the method of this invention is generally applied at room temperature, it is advised to apply such level of temperature as does not give rise to the thermal shrinkage of the raw oriented materials of polyolefin, namely, a temperature higher than the temperature at which glass transition takes place and lower than the temperature at which thermal distortion arises. The reason is that a higher temperature at which thermal distortion arises causes change in K, L and C of the oriented materials of polyolefin due to thermal shrinkage thereof and prevents said oriented materials from being formed into an integral body even when mechanically pressed, and that a lower temperature at which glass transition takes place renders the raw oriented materials brittle and results in the occurrence of cracks in a product obtained. Therefore, preferred temperature for application of the above-mentioned mechanical pressure ranges between 20.degree. and 80.degree. C for high density polyethylene, 20.degree. and 90.degree. C for isotactic polypropylene, 20.degree. and 90.degree. C for polybutene-1, and 20.degree. and 160.degree. C for poly-4-methyl-pentene-1.When the raw oriented materials of this invention consisting of ordinary polyolefin fibers are further blended with, for example, pulp in an amount of not more than 50% by weight, then a mixed paper-like sheet is provided. It is also possible to mix a small amount of inorganic powder or any other material with the subject raw oriented materials.Cross-linking obviously elevates the physical and chemical properties of the product of this invention as in the prior-art polyolefin products. This cross-linking may be effected either by a chemical process using known organic peroxides or by ionizing radiation. However, the latter radiation cross-linking process is more preferred to maintain the dimensional stability of a product obtained.Products prepared by application of the method of this invention include not only sheets, cords, ropes or other elongate articles but also useful industrial materials such as electric insulation material, wrapping paper for heavy objects, writing or printing paper.

摘要翻译： 利用所述材料的压力敏感性，通过机械压制结晶聚烯烃的薄膜或纤维取向材料制备具有优异物理和化学性质的片状，绳状和其它形式的产品的方法。