Abstract: A method for making removable, reusable adhesive products from soft, solvent-free rubber compositions is disclosed. The rubber compositions are packed together by molding them into thin coatings between a release film and a porous substrate to allow curing. The resultant product has highly desirable bonding and release properties on smooth and porous surfaces. Product applications included are automotive windshield covers, home window insulation curtains, photograph mounting boards, and indoor sign-making backgrounds.

Abstract: A plastics shaping mold comprising a layer of hardened resin material fixedly superposed on a metal mold and defining an uneven shaping surface for forming an uneven surface pattern on plastic articles. The plastics shaping mold is prepared by a method comprising the steps of superposing a resin material in a fluid state on a master in sheet form defining an uneven surface inverse to the uneven shaping surface to be formed, allowing the resin material to harden and removing the master, thereby to form the layer of hardened resin material defining the uneven shaping surface.

Abstract: A method of manufacturing bricks with smooth surfaces includes the steps of providing a mould container with a movable bottom, washing the mould container, placing a layer of releasing material in the mould container, filling the mould container with clay and trimming off the container. Only the bottom of the container is filled with a releasing material and the bottom of the container is moved so that it is virtually outside of the mould container.

Abstract: A method of molding and vulcanizing more than 40 rubber products successively by using a curing bladder, which has been treated at the surface thereof with a silicone composition including:(a) 100 parts by weight of a polyorganosiloxane composed mainly of polydimethylsiloxane with a viscosity at 25.degree. C. of from 3,000 to 5,000,000 cst,(b) from 30 to 300 parts by weight of a polymethylhydrogensiloxane with a viscosity at 25.degree. C. of from 10 to 70 cst,(c) from 2 to 25 parts by weight of a finely powderous silica, and,(d) from 0 to 30 parts by weight of an organic acid salt of one or more of metals selected from the group consisting of zinc, magnesium, manganese and cobalt.

Abstract: A method of producing a crosslinked, uniformly foamed article of a polypropylene resin is provided. The polypropylene resin containing a crosslinking agent and a foaming agent is extruded through a long-land die which is provided with a choking die at an intermediate portion thereof; a lubricant is provided on the inner surface of the long-land die; the crosslinking agent is decomposed in the front stage of the long-land die; and the foaming agent is decomposed in the rear stage of the long-land die.An ethylene-propylene random copolymer resin which contains 2 to 10 wt. % of ethylene and has a melt flow rate of 5 g/10 minutes or more at 230.degree. C. and a melt expansion ratio of 1.4 of less at 190.degree. C. is used as the polypropylene resin.

Abstract: A process which comprises (i) the generation of release surfaces by application to predetermined areas of a solid surface of a solution, suspension or dispersion of a release agent and a supercritical fluid that vaporizes from the release agent, (ii) the deposition of a mass onto the release surface containing the release agent, and (iii) the separation of the mass or a product derived from the mass from such surface covered by the release agent. Novel apparatus for carrying out the process are described.

Abstract: A method of coating on a melt contact surface such as that of an injection sleeve for casting, a plunger end face or a mold cavity comprises a step of charging the soot and the melt contact surface with opposite electrical polarities to thereby cause an electrodeposition of the charged soot on the melt contact surface. A preferred apparatus for the soot coating comprises means for producing an air stream surrounding a combustion gas stream including the soot and forming an air curtain for preventing the sprayed soot from scattering.

Abstract: The present invention relates to a disposable concrete forming apparatus. The apparatus includes an elongate, tubular and rigid form having at least one inner wall surface defining an enclosure in which concrete can be poured and allowed to harden. The apparatus further includes a flexible liner of predetermined thickness which lines the inner surface to preclude formation of form lines on the hardened concrete that correspond to markings on the inner wall surface of the rigid form. The flexible liner has at least one outside wall surface for each inner wall surface and is movable between a compressed position permitting insertion of the liner into the enclosure and a normal expanded position with the outside wall surface pressing against the inner wall surface of the rigid form. As a result, no gap is present between the inner wall surface and the outer wall surface.

Abstract: A method of producing cylindrical objects with one or more lobes in which the bore surfaces are completely protected by a surface layer of abrasion resistant and/or corrosion resistant alloy and which protective layer is free of any contamination by the metal of the substrate. A hard, wear resistant, and corrosion resistant nickel-based alloy is especially suitable as lining material for surface of cylindrical products, such as housings or shells used in extrusion and injection molding devices for processing halogenated resins or rubbers. The alloys will preferably also contain 0.5 to 5% silicon and 1 to 4% boron. Also disclosed is a method of producing cylindrical objects with one or more lobes in which the bore surfaces are completely protected by a surface layer of abrasion resistant and/or corrosion resistant alloy, such as the above-described metal-based alloy.

Abstract: Process for molding and vulcanizing tires and other rubber articles, in which in a press with the aid of a bladder negative shapes are pressed into the tire blank under high pressure and vulcanization is performed, the surface of the bladder having applied thereon a solvent which swells the surface, the swollen bladder being provided with a cross-linked, hardened, tightly adhering, elastic release agent film bonded to the bladder by chemical interactions before carrying out molding and vulcanization to prevent sticking of the molded and vulcanized tire to the bladder, the film comprising more than one thin coating each of which is produced by coating the bladder with an organic solvent solution comprising a mixture of a silicon release agent and a moisture or heat curable silicone rubber and curing the coated mixture through exposure to moisture or heat, and conducting at least 300 molding and vulcanizing cycles without recoating the bladder with the release agent film.

Abstract: Elastomer structures having exposed controlled surface release characteristics can be made by coating at least a portion of their surface with a releasing composition comprising (a) a chlorosulphonated polymer; (b) a reinforcing filler and (c) a green tackifying agent. Optionally, these compositions can also contain a chemical curing system and one or more volatile solvent/diluent viscosity-reducing vehicle. In a specific example, the coating are applied to flexible structures used in machines for the manufacture of articles having natural tack due to their rubber or elastomer content.

Abstract: A process for imparting releasing property to a mold which comprises applying to the mold a composition comprising:(A) (1) a fluorine-containing urethane compound represented by the formula ##STR1## and/or (2) a fluorine-containing urethane compound represented by the formula ##STR2## and/or (3) a fluorine-containing urethane compound represented by the formula ##STR3## and (B) at least one of members selected from the class consisting of silicone oil, silicone varnish, wax and a highly fluorinated organic compound and the mold release composition used for the process.

Abstract: A method of making precision low cost molds by applying a plurality of layers of material to a pattern. The method includes providing a pattern of the part to be formed; orienting the pattern on a surface plate in a molding dam; applying a release coating to the surfaces; applying a thin resin layer to form the mold surface; applying a layer of fiber reinforced tooling resin to the thin resin layer; applying an epoxy-dry plaster bonding layer to the tooling resin; inserting a reinforcement framework into the dam; and applying bulk casting plaster to complete the body of the mold.

Abstract: The invention is directed to the method, products and apparatus for the manufacture of a high optical quality sheet of plastic comprising a polyurethane layer having energy-absorbing properties obtained by reactive pouring or reactive pulverization of the reaction components.In accordance with the invention, the polyurethane layer is treated, while it is in a state of ongoing polymerization corresponding to an NCO/CH ratio of less than 0.7, with water in a liquid or vapor form and then subsequently, after rolling with an interpolated film, stocking and unrolling, the layer is subjected to heat treatment.

Abstract: Disclosed herein are a process for producing a carbonaceous thin plate comprisingdisposing a composite material comprising a carbonaceous raw material which is carbonized and solidifies after being softened by heating and paper-like substances which are carbonized without melting between the pressing-surfaces of a heating press, so as to sandwich said carbonaceous raw material between said paper-like substances and to contact said paper-like substances with each of the pressing-surfaces of said heating press,press-molding said composite material by raising a temperature of said heating presscontinuously heating the thus press-molded composite material under a pressure, thereby carbonizing the thus press-molded composite material, andcalcining the thus carbonized material under a reduced-pressure or in an inert gas.

Abstract: A mold forming method in which a pattern is made of an organic material such as foamed polystyrene and at least a portion of the outer or inner surface of the mold pattern is covered by a thin coating, and surrounded with a mold material. The pattern is then dissolved by a solvent, leaving the coating undissolved. The coating is finally removed by a solvent contained in a slip which is poured into the cavity provided with the coating.

Abstract: A solid film lubricant composition for hot glass contacting surfaces of glass handling equipment and metal molds used in manufacturing glass articles. The solid film lubricant composition is a solution of a solvent, graphite, a solvent-soluble, further curable organopolysiloxane, and NaOH to make the solution alkaline. The solution is easily sprayed on hot glass contacting surfaces such as the interior of the molds to form a coating that is curable at room temperature.

Abstract: Process for lubricating a surface for the manufacture of a glass object, in which a layer of lubricant is periodically deposited on the surface.This layer of lubricant is produced with the aid of a source of heat such as an oxyfuel flame having a temperature higher than 2000.degree. K. through which there is injected during a given period of time a gaseous hydrocarbon or a mixture of gaseous hydrocarbons comprising at least 15% of a constituent in respect of which the ratio fo the number oc carbon atoms to the number of hydrogen atoms C/H is higher than 0.75. The rate of injection of the hydrocarbon through the flame and the temperature of the latter are controlled in such manner as to obtain a porous layer of carbonaceous particles capable of burning in the air when they are deposited on the glass object when the latter is still hot.

Abstract: Polymeric articles made of, for example, polyethylene and copolymers of ethylene, are made more adherent to paint or dyes by first nitrating the polymer, then shaping or forming it in a mould having a polar surface and finally, cooling it in contact with that surface, or extruding a nitrated polymer onto a polar surface and allowing to cool in contact with that surface.

Abstract: Barriers used for separating silicone pressurizing medium from articles during curing, thereby protecting the article from silicone contamination. A composite precursor is substantially encapsulated by a barrier coating that is capable of substantially separating the composite precursor from silicone polymers at elevated temperatures during curing. The barrier coating is also capable of being chemically removed from the composite precursor subsequent to its cure without substantially damaging the composite. Composites are molded by protecting a composite precursor from a silicone pressurizing medium during curing utilizing a barrier coating. The method comprises encapsulating a composite precursor with a coating that is substantially capable of separating the composite precursor from silicone polymers at elevated temperatures. The coating is also capable of being chemically removed from the composite without damaging the composite.

Abstract: Detergent bars (soap or non-soap) are stamped or imprinted using a die or dies having a modulus of elasticity in the range 5.times.10.sup.5 to 1.times.10.sup.7 Nm.sup.-2. This gives reduced adhesion of detergent to die, reduced die-blocking and consequently reduced marring of bars. Preferably each such die has a facing layer of elastomer so as to achieve the desired low modulus of elasticity which preferably is distinctly less than that of the detergent.

Abstract: A mold for molding an optical disc includes a first mold member having a recess, and a second mold having a body and a plate-like sintered ceramic member secured to the body and having a flat seat surface. The recess and the flat seat surface jointly provides a mold cavity when the first and second mold members are mated together. A disc-shaped thin stamper is adapted to be seated on and detachably secured to the flat seat surface. The ceramic member is made of a ceramic material having Rockwell hardness (A-Scale) of not less than 90, so that the flat seat surface is not subjected to undue damage for a prolonged period of time.

Abstract: A process for producing polyurethane foam articles is described, in which the article is produced in the conventional manner by foaming in a mould and a release agent is applied to the mould surface prior to filling with the foam-producing components. According to the invention, a solvent-free, aqueous release agent is used in combination with one or more alkali metal and/or ammonium salts of higher fatty acids and one or more higher alcohols and the combination is applied in the hot state, preferably at a temperature of at least 75.degree. C. to the mould surface. In addition, an additive is described, which is suitable for performing the process according to the invention and contains one or more alkali metal and/or ammonium salts of higher fatty acids, one or more higher alcohols and otherwise water.

Abstract: The present invention provides a method for producing silicone rubber moldings composed of a uniform, smooth and hard exterior layer and a relatively soft interior portion. In accordance with this method the surfaces of the mold cavity are coated with an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms before the curable organosiloxane used to form the interior portion of the molding is injected into the mold cavity and cured.

Abstract: Coated, reinforced composites are prepared by a process in which(i) a liquid composition comprising a photocurable residue and a residue having at least one epoxide group or phenolic hydroxyl group is applied to the surface of a mould,(ii) the composition is exposed to actinic radiation until it solidifies,(iii) reinforcement and a thermosettable composition are applied to the solidified layer, this composition containing an epoxide resin or a phenolic resin,(iv) the assembly is heated to form a cured moulding, and(v) the moulding is removed from the mould.

Abstract: Molds for injection molding are produced by providing a primary mold core, coating the primary mold core with a water-resistant coating layer, applying on the water-resistant coating layer a separating layer, spraying a metal shell on the separating layer, arranging a rear filling on the shell so as to form a tool part, and supplying water to the water-soluble layer so as to remove the tool part.

Abstract: A method of assembling a refrigerator having an outer metal casing, an inner plastic liner and foamed-in-place thermal insulation between the casing and liner bonding them together including a high stress area in the liner that can cause the liner to crack due to a difference in expansion and contraction relative to the outer metal casing. The method comprises forming the metal casing, vacuum forming the liner from plastic material, placing at least one elongated slot open at one end and closed at the opposite end in the liner located in the high stress area, placing the liner inside the casing in spaced relationship thereto, and foaming the space between the casing and liner to bond them together.

Abstract: A binder/release system for the preparation of molded articles, especially lignocellulosic composites, which utilizes in combination with isocyanate-based binders a fatty material as an internal and/or external release agent, the fatty material being at least one polymerized fatty acid and/or at least one polycarboxyl compound containing a polymeric fatty radical(s).

Abstract: A process for producing molded articles, especially molded polyurethane foam articles, wherein the mold is treated with an aqueous release agent or a concentrate of one or more release-active substances in organic solvent. The release agent is preheated, e.g. by an atomizer supplied with hot pressurized air, prior to being applied to the mold. The process enables the efficient use of water-base release agents and thus reduces the emission of harmful organic solvents into the atmosphere.

Abstract: A decorative speaker cover and a method for fabricating a speaker cover for use in a ceiling or wall comprising panels, the speaker cover having an appearance which blends with other panels so that it conceals the presence of a speaker system while providing satisfactory transmission of sound from the speaker system. The decorative speaker cover is fabricated by first forming a mold liner suitable for generating a facsimile of a ceiling or wall panel. Next, the mold liner is placed in a molding container and a closed cell expandable foam system is uniformly spread over the mold liner so that the foam rises vertically. The thickness of the resulting cast is reduced to a dimension below which acoustic transmission loss is not discernable by human ears.

Abstract: A process for producing a hollow fiber mass transfer module with a number of hollow fibers sealed into a housing is improved according to the invention with regard to the development of a desirable flow space in the surface area of the hollow fibers by the fact that a spacing material is applied to the outsides of the hollow fibers before their insertion into the housing (2). The thickness of the material is chosen to conform to the desired separation of the hollow fibers. The hollow fibers are arranged substantially parallel and inserted as a bundle into the housing and are fixed with the grout. The spacing material can have a layered or particulate and granular form. A hollow fiber mass transfer module produced by the process pursuant to the invention has hollow fibers suitably arranged at uniform mutual spacings.

Abstract: A method and apparatus for foam molding packaging using a staged vacuum system to place a plastic sheet used as a release agent in conformity with the surface of the mold is provided. A mold having a complex image divides the mold image into separate and distinct sections. A plastic sheet is placed loosely over the mold in covering relation to the image and a vacuum is drawn on the surfaces of the separate and distinct sections of the mold image in a staged sequence to cause the plastic sheet to conform to the surfaces of the mold image on the mold.

Abstract: A method for molding high water, high resiliency (HR) polyurethane foam articles is disclosed wherein a silicone mold release composition is used to treat the surfaces of a mold. The composition imparts release characteristics to the mold which last through multiple molding cycles, allow recoating with said composition and allows the production of defect-free foam articles. The composition consists essentially of a high and a low molecular weight hydroxyl endblocked polydimethylsiloxane, a siloxane crosslinker having SiH functionality, a catalyst and an inert solvent.

Abstract: A method and apparatus of foam molding packaging using a positive vertical mold is provided in which a vertical mold with sides having channeled vertical flap areas is automatically covered with a plastic sheet. Brushes, assisted by a vacuum assure the plastic sheet conforms to the mold including the flap areas. An open-ended carton having upper and lower flaps is placed over the mold so that the lower flaps are disposed vertically and cover the vertical flap areas. Foam precursors are dispensed into the carton and its top sealed to allow foaming within the carton. The carton is then removed from the mold with the foam cushioning fully formed therein including the carton flaps which cover the top of the article to be packaged therein.

Abstract: The present invention is directed to a process for the continuous production of elongate hollow bodies or inner linings for such hollow bodies, from a liquid material wherein the peripheral surface of a mandrel rotating about a horizontal or slightly inclined shaft is covered with a separating film and the liquid material is applied to said separating film and the resulting hollow body is continuously drawn from the mandrel in the axial direction of the shaft while observing the solidification speed of the material, the improvement wherein the separating film is applied to the mandrel in the axial direction of the shaft and to an apparatus for the use therein.

Abstract: An improved window gasket assembly and the apparatus and associated method for reaction injection molding such as assemblies, as well as other molded articles, are disclosed. The gasket is preferably integrally molded from an elastomeric material such as urethane onto a substantially transparent window panel. The gasket and window assembly can then be mounted and secured directly to vehicle body panel opening, for example, with adhesives, thereby eliminating the need for discrete mechanical fasteners. In a preferred embodiment of the invention, an improved aftermixer and gating apparatus includes a mixing body in which a flowable multi-constituent molding material is separated into a number of generally serpentine mixing passageways and reunited in a common mixing cavity before being conveyed through a fan-gate passageway to the mold cavity.

Abstract: An improved procedure for manufacture of optical replication products comprising the use of a thin amorphous coating of carbon as a protective coating which also facilitates release during replication, between master and replication members. Particular attention is given to controlling the compressive forces of the carbon layer to provide good mechanical coatings on suitable optical surfaces. Thereafter, the replicated members may themselves be coated with the carbon as a protective coating only or for further use as a release-promoting "submasters".

Abstract: Disclosed are biodegradable tenacious compositions comprising a biodegradable lubricating oil and a biodegradable resinous component selected from the group consisting of colophonium-containing resins, colophonium and mixtures thereof. Also disclosed are methods for using such compositions and articles coated therewith.

Abstract: Disclosed is a method of fabricating a prosthetic member (112) having personalized features of the patient, and being formed to provide an individualized fit to the patient's extremity (18). A rigid jacket (30, 32) is first formed around the uninsured foot (10) and the amputated extremity (18). The limb characteristics are impressed into an alginate (44) lining within the jackets (30, 32). A stone material poured into the alginate lining (44) forms stone models (48, 50) of the patient's limbs. A wax preliminary model (64) is scuplted in the likeness of the stone foot model (48) and used to form final stone mold halves (100, 102). The contour of the stone extremity model (50) is adjusted according to the tissue texture of the patient to provide an individualized fit. A gelatinous silicone is injected inside the final mold (100, 102) and allowed to form around the extremity model (50) to thereby provide the body of the prosthetic member (112) and the conformal sleeve (132 ).

Abstract: A process for the production of a safety pane comprising a sheet of glass and at least one polyurethane-based layer having energy-absorbent properties. The polyurethane-based layer having energy-absorbent properties is formed directly on the sheet of glass by the reactive injection, under a pressure between 2 and 10 bars, between said sheet of glass and a rigid countermold, of a reactive mixture of an isocyanate component having a viscosity under 5000 centipoises at 40 degrees C. and a polyalcohol component, with the isocyanate component containing at least one aliphatic or cycloaliphatic diisocyanate, or a prepolymer of these isocyanates, with the polyalcohol component containing at least one long difunctional polyalcohol having a molecular mass between 500 and 4000 and at least one short diol as a chain extending agent.

Abstract: The invention is directed to a process for dotting molding tools with droplets of liquid or suspended lubricant in the production of shaped articles in the pharmaceutical, food, or catalyst fields. Pressurized lubricant solutions or suspensions and pressurized gas are alternately passed through capillaries, in conjunction with alternating single-substance nozzles, in such a way that drops are formed on the nozzle surface, in between the jets of gas, and are then detached form this surface and directed to specific zones of pressing tools. The apparatus comprises fast-acting valves for the brief release of pressurized gases and lubricant liquids or suspensions. The delivery lines of a gas valve and a liquid valve combine upstream of a capillary, and single-substance nozzles are mounted at the end of the capillaries.

Abstract: A process is disclosed for fabricating a free-standing thin or thick film structure. One embodiment of the process includes the steps of providing a substrate of a first refractory material, forming a layer of carbon on the substrate, and depositing a film of a second refractory material on top of the layer of carbon. This sandwich structure is heated in an oxidizing ambient to cause the oxidation of the carbon layer leaving the second refractory material as a free-standing film.

Abstract: The present invention relates to a method of manufacturing a release paper characterized in that a mixture of polyolefin and a silicone release agent compatible therewith comprising a reaction product of polymethyl hydrogen siloxane, vinyl group-containing poly-dimethyl siloxane and at least one of olefins or polyolefins having one or more double-bonds is extruded onto a substrate of paper, fabric, film etc., the laminate is heat treated for the release agent contained in the mixed layer of the above-mentioned laminate to bleed onto the surface of the mixed layer to be thus localized and the localized release agent is fixed by curing.The release agent's compatibility with the polyolefin, and this film forming and stretching properties are improved, and since the release agent of high concentration is localized and fixed by curing on the surface of the release agent layer, only a small amount of the release agent is needed.

Abstract: A method of processing hydrocolloid adhesive material includes the steps of extruding a sheet of the hydrocolloid adhesive material from a vacuum extruder, applying a liner of release material to at least one side of the sheet, under pressure, and while the sheet is at an elevated temperature and maintaining the liner and the sheet under tension during cooling of the sheet.

Abstract: Process for manufacturing of molded objects by hot-pressing lignocellulose-containing materials with polyisocyanates as binders while using an agent to release the molded article from the surface of the metal press used. A mixture of the organosilicon compounds is applied onto the surface of the cauls or molds which faces the material to be pressed, and cured at a temperature from 100.degree. to 200.degree. C., preferably in the presence of known curing catalysts. The mixture of organosilicon compounds comprising(a) 20 to 65 weight percent of a silicone resin of the general formula ##EQU1## in which R.sup.1 is a low molecular weight alkyl radical with 1 to 4 carbon atoms,a has a value of 1 to 1.7,b has a value of 0.3 to 1.0;(b) 30 to 65 weight percent of an .alpha.,.omega.-methylsiloxanediol with an average molecular weight of 1,000 to 20,000;(c) 5 to 15 weight percent of a silicate ester of the general formula ##EQU2## in which R.sup.

Abstract: A method for molding articles where a composition is used to treat at least one shape determining face of a mold to impart durable release characteristics to said face which last through multiple molding cycles. The compositions comprise by weight 20 parts of primarily hydroxyl endblocked polydimethylsiloxane, 2 to 10 parts of alkyltriacetoxysilane, 20 to 80 parts of nonreactive organic solvent, and, optionally, 0.001 to 2 parts organometallic catalyst.

Abstract: A molding process for producing a molded plastic product with a resin coating layer formed on its surface, which comprises electrostatically coating a powdery resin composition on the inner surface of a mold, filling and molding a plastic material in the mold to form a molded plastic product, and plasticizing, under compression, said powdery resin composition by the heat of the filled plastic material and/or by the heat for molding the filled plastic material, to form a resin coating layer securely bonded to the surface of the molded plastic product by anchor effect.

Abstract: The present invention concerns a process for a thin sheet molding of a thermoplastic resin easily and economically and also the thin oriented sheet molding prepared by such a process. Its specific feature resides in the steps of lubricating the inner surface of die, laying over one another thermoplastic resin blanks while being not adhered to each other in a die, compressing the layered structure at a temperature higher than the glass transition temperature of the thermoplastic resin blanks and separating the oriented molded products from each other.

Abstract: A process for solvent casting acrylic films having superior properties by casting a solution comprising an organic solvent and a polymer system of one or more acrylic polymers onto a carrier, removing the solvent thereby forming the film on the carrier, and stripping the film from the carrier, is disclosed.The polymer system comprises at least one polymer having the following properties: Total Elongation (%) of about 120-250; Tear Resistance of about 4.5-12.5 g/mil (which is about 177-492 mg/micron); Tensile Strength of about 4500-5000 lbs/in.sup.2 (about 317-387 kg/cm.sup.2); Molecular Weight (amu) of about 250,000-500,000; Acid Content (%) of about 0.05-5.0; and Tucon hardness (Knoop No.) of about 6-12.The acrylic film has Total Elongation, Tensile Strength, Tear Resistance, Acid Content and Tucon hardness in the aforesaid ranges, and is substantially free of reactive groups, such as hydroxy groups. The residual solvent in the film is (weight %) about 0-3.

Abstract: A dry wall interlocking building block system includes a method of manufacturing moulds for casting building blocks, in which master forms corresponding in shape and size to the required blocks are cast from a cold-pouring compound in collapsible core-boxes, and in which a mould is built up around the master forms (7) by securing the forms to a casting table (8), placing metal liner plates (9) against the sides of the forms, filling the spaces around the liner plates with a similar cold-pouring compound, allowing the compound to set, and withdrawing the forms to leave a plurality of mould cavities. The mould can then be mounted in a block making machine for large scale casting of concrete blocks in the mould cavities. One feature of the preferred mould is that the liner plates are detachable, countersunk bolts (10) having been fitted in holes in the liner plates (9) prior to filling the spaces around the plates. The invention also includes a two-recess building block cast in the above mould.