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    Retractable blade unit for projectiles
    61.
    发明授权
    Retractable blade unit for projectiles 失效
    项目可回收叶片单元

    公开(公告)号：US3602459A

    公开(公告)日：1971-08-31

    申请号：US3602459D

    申请日：1969-07-14

    Applicant: SNIA VISCOSA

    Inventor： PESARINI MARIO ,  GALEAZZI PIERO ,  TOSTI CARLO

    IPC: F42B10/14 ,  F42B13/32

    CPC classification number: F42B10/14

    Abstract: A retractable tail unit for guiding projectiles, which unit includes an idle bushing mounted in the rear part of the cylindrical body of the projectile. The bushing has the same diameter as the outer diameter of convergent and divergent composite body portions of said cylindrical body, all being axially aligned with said body. A plurality of substantially trapezoidal shaped blades are pivot mounted at one end on a pivot pin mounted slantwise on the bushing, with the blades in their ''''closed'''' position lying flat tangentially to coextensive portions of the bushing and of the convergent portion of the cylindrical body of the projectile, and parallel to the axis thereof. The blades, when in their ''''closed'''' position, are contained within a circular ring area or recess defined by or between a combination of the body of the convergent portion and of the bushing, and by the outer diameter of the cylindrical body of the projectile. The center of gravity of these blades, as a result of the axial acceleration in the initial launching stage, is so displaced as to cause a moment on the blades which effects the opening and the extension of each blade about the slanting or canted pivot pin, the blades thus placing themselves radially with respect to the axis of the cylindrical body of the projectile, at the desired attachment angle.

    Process for preparation of spinnable solutions of acrylonitrile polymers or copolymers having a high-acrylonitrile content
    67.
    发明授权
    Process for preparation of spinnable solutions of acrylonitrile polymers or copolymers having a high-acrylonitrile content 失效
    制备具有高丙烯腈含量的丙烯腈聚合物或共聚物的可纺丝溶液的方法

    公开(公告)号：US3379670A

    公开(公告)日：1968-04-23

    申请号：US65933067

    申请日：1967-08-09

    Applicant: SNIA VISCOSA

    Inventor： DEMETRIO CORRADI ,  ALBERTO PASIN

    IPC: C08F20/42 ,  C08F20/44 ,  C08G18/10 ,  C08J9/24 ,  C09D175/04

    CPC classification number: C08G18/10 ,  C08F2/36 ,  C08F20/42 ,  C08F20/44 ,  C08J9/24 ,  C09D175/04 ,  C08G18/8061 ,  C08L27/04

    Abstract: Spinnable solutions of polyacrylonitrile, or of copolymers containing over 85% by weight of acrylonitrile, are produced by polymerization of the monomer(s) in dimethyl formamide in at least two sequential stages, in the first of which the polymerization is carried out at 60 DEG to 65 DEG C. until reaching not less than 30% and not more than 40% conversion of the monomer(s), while in the second stage or the following stages the polymerization is carried on under controlled temperature conditions until reaching a higher conversion, the amount of dimethyl formamide and catalyst required to attain said higher conversion being divided into as many fractions as there are stages and one of said fractions being individually added at the beginning of each stage. The final conversion attained is desirably in the range 70 to 80%. The temperature conditions may be controlled by carrying out the process under sub-atmospheric pressure, in which case the polymerization is terminated by increasing the pressure and distilling off unreacted monomer(s). In the examples, the polymerization is carried out in two stages. In Examples 1 and 3 copolymers of acrylonitrile, sodium allyl sulphonate and methyl methacrylate are prepared and in Example 2 a copolymer of acrylonitrile, sodium allyl sulphonate and ethyl acrylate. Lauroyl peroxide is used as catalyst and thiourea dioxide is present in the reaction solutions of Examples 1 and 2.

    Abstract translation: 聚丙烯腈或含有超过85重量％丙烯腈的共聚物的可纺溶液是通过在至少两个连续阶段中将二甲基甲酰胺中的单体聚合制备的，其中第一个聚合反应在60℃进行 至65℃，直到达到不少于30％且不超过40％的单体转化率，而在第二阶段或后续阶段，聚合在受控温度条件下进行直至达到更高的转化率， 达到所述较高转化率所需的二甲基甲酰胺和催化剂的量被分成与阶段相同的分数，并且在每个阶段开始时分别加入一个所述级分。 所得到的最终转化率优选为70〜80％。 可以通过在亚大气压下进行该方法来控制温度条件，在这种情况下，通过增加压力并蒸发未反应的单体终止聚合。 在实施例中，聚合分两个阶段进行。 在实施例1和3中，制备丙烯腈，烯丙基磺酸钠和甲基丙烯酸甲酯的共聚物，在实施例2中是丙烯腈，烯丙基磺酸钠和丙烯酸乙酯的共聚物。 月桂酰过氧化物用作催化剂，二氧化硫脲存在于实施例1和2的反应溶液中。

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