Patent GB-445478-A (GB)
Title: Improvements in or relating to a method of carrying out reactions for the conversion of liquid materials into solid or semi-solid products
IPC: C08F20/12
Filed: 1934-10-09
Abstract: <PICT:0445478/IV/1> Methacrylic acid esters or mixtures thereof are polymerized to produce formed articles such as plates, bars or strips, by carrying out the polymerization in relatively narrow chambers which are subjected over most of their surface to the action of a temperature regulating medium, which may be gaseous or, preferably, liquid, and controlling the temperature of said medium. The temperature of the medium may be first adjusted so as to bring the contents of the chambers to the required temperature for carrying out the polymerization, e.g. 70 DEG  C., after which, if the reaction is exothermic, the heat of reaction may be conducted away by suitably controlling the temperature of the regulating medium.  Before introduction into the chambers the starting materials may be freed from bubbles, e.g. by evacuation, heating or boiling.  The reaction may be carried out in flat chambers, e.g. of metal, of say 2--3 mm. or up to 10 mm. or in some cases even greater thickness, which are subjected to the action of the temperature regulating medium on all faces or on their two flat sides.  A plurality of such chambers may be combined into a system of chambers separated by interspaces through which the temperature regulating medium circulates, or such a system may be built up from a plurality of frames.  After completion of the reaction, the product is removed from the chambers, e.g. by removing one side or one edge and allowing the plate to fall out. Removal of the products may be facilitated by providing between the reaction product and the walls a separating layer, e.g. of viscose, gelatine or glue or of paper or woven material preferably impregnated with glue or gelatine, which separating layers may be in the form of bags or envelopes which, after being filled with the material to be polymerized, may be closed by folding over the upper part, and in which the polymer may be subsequently stored or transported.  Instead of being flat, the chambers may be in the form of tubes of cylindrical, oval or square cross - section, which can be subjected over the whole or almost the whole of their surface to the action of a heating medium.  In the apparatus shown, the polymerization chambers are formed of frames b between heat regulating chambers a to which the regulating medium is supplied by pipes c and from which it is withdrawn by pipes d. The system is supported by rollers k on a frame or on rails f, and is pressed together between heads h, h<1> and the spindle g, whilst each pair of chambers may be connected by quick acting connections, e.g. hooks or chains.  The frames may be rectangular, oval, square or circular, and the side faces of the regulating chambers may be flat or may have raised or depressed portions to produce suitable shapes in the polymer, e.g. they may be grooved or fluted so as to enclose a tubular space.  The reaction chambers are filled through pipes e by suction or by application of pressure, and in the latter case the pressure may be maintained during polymerization.  The products may be employed in the form in which they are produced, e.g. as glass substitutes, or may be shaped into other forms, e.g. plates may be placed between metal plates of larger dimensions and subjected to heat and pressure to produce thinner plates of larger area.  The products may also be employed for the manufacture of safety glass.  Products in the form of rods may be cut into small plates of suitable thickness, e.g. 0,5 mm. to 1 cm., which may be placed between metal or glass plates and heated and pressed into thinner layers, e.g. of 0,05 to 0,2 mm. thickness, producing round or oval artificial glass discs or discs of splinterless glass for optical purposes, e.g. for protective spectacles or goggles.  In examples: (1) methacrylic acid ethyl ester, mixed with a softening-agent, e.g. isobutyl phthalate, and an accelerator, e.g. benzoyl peroxide, is heated in flat chambers 5 mm. thick at 70 DEG  C.; (2) a mixture of methacrylic acid ethyl and methyl esters with the addition of isobutyl phthalate is similarly polymerized in layers 10 mm. thick; (3) methacrylic acid ethyl ester alone is polymerized as in (1).  The Specification as open to inspection under Sect. 91 comprises the application of the process and apparatus to any reaction for the conversion of liquid materials into solid or semisolid products, e.g. the polymerization of unsaturated organic compounds such as esters of acrylic acid, vinyl acetate or styrene, or condensation reactions such as the manufacture of phenol-aldehyde condensation products.  In an additional example, vinyl acetate is polymerized as in (1) above.  An application of the process to the production of safety glass is described in which a monomeric or partially polymerized product is polymerized between two glass plates secured together by a strip of elastic yielding material (e.g. a rubber-like polymerization product, a polymerization product of methyl acrylate, paper or rubber) interrupted so as to provide an opening for the introduction of the liquid to be polymerized. Alternatively, a number of small elastic discs are placed at intervals round the edges of the space between the plates, and three of the edges are closed in a liquid tight manner, e.g. by means of paper.  Safety glass may also be produced by placing a comparatively thick sheet of polymerization product symmetrically between two sheets of glass of greater area and applying pressure until the polymerization product is compressed to a thinner sheet of area sufficient to fill the space between the plates.  This subject-matter does not appear in the Specification as accepted.ALSO:<PICT:0445478/III/1> The polymerization of methacrylic acid esters is carried out in relatively narrow chambers which are subjected over most of their surface to the action of a temperature regulating medium, which may be gaseous or, preferably, liquid.  The reaction chambers may be flat chambers, e.g. of metal, of say 2--3 mm. or up to 10 mm. or in some cases even greater thickness, and may be subjected to the action of the temperature regulating medium on all faces or on their flat sides.  A plurality of such chambers may be combined into a system of chambers separated by interspaces through which the temperature regulating medium circulates, or such a system may be built up from a plurality of frames.  In order to facilitate the removal of the product after the reaction, there may be provided between the reaction product and the walls a separating layer, e.g. of viscose, gelatine or glue or of paper or woven material preferably impregnated with glue or gelatine, which separating layers may be in the form of bags or envelopes which, after being filled with the material to be polymerized, may be closed by folding over the upper part.  Instead of being flat, the chambers may be in the form of tubes of cylindrical, oval or square cross-section, which can be subjected over the whole or almost the whole of their surface to the action of a heating medium.  In the apparatus shown in the drawings, the polymerization chambers are formed of frames b between heat regulating chambers a to which the regulating medium is supplied by pipes c and from which it is withdrawn by pipes d.  The system is supported by rollers k on a frame or on rails f, and is pressed together between heads h, h<1> and the spindle g, whilst each pair of chambers may be connected by quick acting connections, e.g. hooks or chains.  The frames may be rectangular, oval, square or circular, and the side faces of the regulating chambers may be flat or may have raised or depressed portions to produce suitable shapes in the polymer, e.g. they may be grooved or fluted so as to enclose a tubular space.  The reaction chambers are filled through pipes e by suction or by application of pressure.  The Specification as open to inspection under Sect. 91 comprises the application of the process and apparatus to polymerization reactions in general.  This subject-matter does not appear in the Specification as accepted.